Focal persistent disturbances of cortical rhythm. Decoding the electroencephalogram (EEG) indicators of the brain

MONITORING OF CHILDREN WITH IDENTIFIED EPILEPTIC FORM ACTIVITY ON EEG AND NOT SUFFERING EPILEPSY
Panyukova I.V.
Children's City Clinical Hospital No. 9, paroxysmal conditions room, Yekaterinburg
According to world literature, epileptiform activity is detected in 1.9-4% of children without epileptic seizures during a routine electroencephalographic study. Most often, regional patterns are recorded, mainly in the form of DND. Generalized epileptiform activity is much less common.

In 2009, 115 children with identified epileptiform changes on the EEG were sent to the paroxysmal conditions room of Children's Clinical Hospital No. 9 for consultation. An EEG was done for headaches, hyperactivity, attention deficit, delayed speech development, cerebral palsy, and sleep disorders.

Some children underwent a repeated EEG study, and, if possible, video-EEG sleep monitoring, since in some cases only conclusions about epileptiform disorders on the EEG were presented, or the recording of the study was insufficiently informative or of insufficient quality.

During the study of EEG and repeated studies, epileptiform activity was confirmed in 54 patients. In other cases, myogram, ECG, rheogram artifacts, polyphasic complexes, paroxysmal activity, etc. were described as “epileptiform activity.”

In most cases, epileptiform activity was recorded in boys – 59% (32 children).

The age of children with identified disorders ranged from 5 to 14 years. Most often, epileptiform activity was recorded at the age of 5–8 years and was represented by DEND. Generalized peak-wave complexes were recorded in 3 patients.

In most cases (41), epileptiform activity in the form of DED had a low index of representation and was continuous in only 4 patients.

The structure of diagnoses of children with identified epileptiform activity was as follows: cerebroasthenic syndrome (30); autonomic dysfunction syndrome (6); attention deficit hyperactivity disorder (6); cerebral palsy (5); epileptiform cerebral disintegration (3); consequences of a neuroinfection (2); consequences of severe head injury (2). Some children underwent additional examination (CT, MRI of the brain).

Neuroimaging revealed the following disorders in this group:

Congenital arachnoid cyst of the temporal lobe – 2

Periventricular leukomalacia – 3

Cerebral atrophy – 2

For some children, taking into account neuroimaging data and the presence of epileptiform activity on the EEG, anticonvulsant therapy is recommended for 3-6 months with subsequent EEG monitoring.

Valproic acid drugs were prescribed to 6 children (20-25 mg/kg body weight) and 4 children were prescribed trileptal (25 mg/kg). Trileptal is prescribed to children with identified cerebral cysts of the temporal lobe and cerebral palsy (hemiparetic form).

During the year of observation of children in this group, no seizures were recorded. Further observation of these patients and monitoring of electroencephalographic disorders is necessary for the purpose of possible correction of non-epileptic disorders associated with epileptiform activity.
TACTICAL ALGORITHMS IN THE WORK OF THE EEG-VIDEO MONITORING OFFICE OF A SPECIALIZED NEUROLOGICAL DEPARTMENT
Perunova N.Yu., Safronova L.A., Rylova O.P., Volodkevich A.V.
Regional Children's Center for Epilepsy and Paroxysmal Conditions

CSTO No. 1, Ekaterinburg
Electroencephalographic video monitoring (EEG-VM), which allows synchronizing EEG and video information, visualizing epileptic seizures, making clinical-electroencephalographic comparisons and clarifying the form of the disease, is currently the most informative method for standard diagnosis of epilepsy and non-epileptic paroxysmal conditions

At the CSCH No. 1 in Yekaterinburg, the EEG-VM office was created in 2002. There are still no standards for conducting EEG-VM studies in Russia, so many technological approaches were developed by the office staff independently.

During the year in the EEG-VM room for the period 2002-2009, an approximately constant number of children and adolescents under the age of 18 were examined (1028-1162). Children staying in the hospital of CSCH No. 1 made up 58%, outpatients - 42%. Among all those examined, 14.6% were children of the first year of life.

As a result of EEG-VM, the diagnosis of epilepsy was excluded in 44% of those examined. The reasons for examination in this group of patients were: vegetative-vascular dystonia with syncopal paroxysms, hyperkinetic syndrome, paroxysmal sleep disorders, migraine, motor stereotypies, conversion disorders, infantile masturbation.

The diagnosis of epilepsy was established or confirmed in 56% of those examined. Epilepsy in this group was assessed as generalized in 61% of cases, and as partial in 39%.

Based on many years of experience in conducting EEG video monitoring studies in children and adolescents, we have proposed some special technological approaches or tactical algorithms.

Conducting the study while awake in most patients includes a standard set of functional tests (opening and closing the eyes, rhythmic photostimulation in various frequency ranges, phonostimulation, hyperventilation). A sensitization test for photosensitivity epilepsy is performing RFS immediately after waking up. Depending on the characteristics of the course of the disease, special methods of provocation can be used - playing, tactile provocation, watching television (for television epilepsy), exposure to a sharp sound (for startle epilepsy), reading complex text (for reading epilepsy). Patients with pseudoepileptic seizures may be exposed to provocative influences during conversation. Monitoring of young children while awake and patients with impaired consciousness is usually carried out without the use of functional tests (with the exception of RFS when indicated).

A study in the sleep state in most cases turns out to be quite informative when recording 1-2 cycles of daytime sleep after preparation by sleep deprivation. Studies in the state of night sleep (8 hours) are carried out with exclusively nocturnal nature of attacks, differential diagnosis of epileptic seizures and paroxysmal sleep disorders, behavioral disorders with the inability to sleep during the day. The office has the technical capabilities and experience in conducting long-term studies (24-48 hours), however, the need for such studies arises, in our opinion, only in special situations (for example, during clinical trials). Polygraphic research is technically possible using this diagnostic complex and is carried out if necessary - for example, when diagnosing epileptic breathing disorders.

We believe that the EEG-VM office should belong only to the clinical service and be located on the territory of a specialized department (to avoid untimely provision of assistance in the development of epileptic seizures, especially their series and statuses). Adequate interpretation of data can only be carried out by doctors with basic training in neurology - epileptology, who have also received training in neurophysiology (EEG). An individual approach to the doctor’s development of a program or tactical examination algorithm for each patient allows one to obtain the maximum amount of diagnostic information.

FOCAL EPILEPSY IN YOUNG CHILDREN:

EXPERIENCE OF TRILEPTHAL THERAPY
Perunova N.Yu., Volik N.V.
Regional Children's Clinical Hospital No. 1, Yekaterinburg
Focal epileptic seizures in infancy are difficult to identify due to the peculiarities of their clinical phenomenology; they are often detected only during EEG video monitoring. In this regard, one gets the erroneous impression that focal forms of epilepsy are rare in children of the first year of life. Meanwhile, if among epilepsies with onset in the first year of life, West syndrome accounts for 39-47%, then the share of symptomatic and cryptogenic focal epilepsies accounts for 23-36% (Caraballo et al., 1997; Okumura et al., 2001).

The etiological factors of symptomatic focal epilepsies with onset in infancy include primarily cerebral dysgenesis (focal cortical dysplasia, pachygyria, polymicrogyria, schizencephaly, neuronal heterotopia, hemimegalencephaly), the neuroimaging diagnosis of which is hampered by the incompleteness of myelination processes in young children. The development of symptomatic focal epilepsies in infancy is also possible against the background of the consequences of perinatal hypoxic-ischemic brain damage with focal gliosis, mesial temporal sclerosis, Sturge-Weber syndrome, tuberous sclerosis, and brain tumors.

The semiology of partial seizures in infancy often includes motor phenomena (tonic or clonic, involving the face, 1 or 2 limbs, half the body), as well as versive manifestations (deviation of the eyes, head). Possible vegetative symptoms (pallor or redness of the face, mydriasis, tachypnea or apnea), nodding, various types of automatisms (oroalimentary, facial, complex gestures).

Data from EEG video monitoring studies show combinations of epileptic seizures in accordance with the localization of the focus (Rather J.P. et al., 1998). The complex of frontal seizures in infants includes tonic postures, nodding, cessation of activity, myoclonus of the eyelids, gestural automatisms, and complex motor behavior. “Rolandic” seizures are manifested by unilateral or bilateral hypertonicity of the limbs, partial clones, and lateralized motor phenomena. Temporal lobe seizures include cessation of activity, staring, and oroalimentary automatisms. Finally, occipital seizures are characterized by deviation of the eyes, oculoclonus, myoclonus of the eyelids, sometimes “gazing” and late oral automatisms; prolonged epileptic blindness is possible.

Interictal changes in the EEG initially manifest themselves as rhythmic slowing, frequency-amplitude asymmetry, and sometimes regional slowing. Epileptiform activity may appear later than seizures and manifests itself in the form of spikes, sharp waves, as well as “sharp-slow wave” complexes that are polymorphic in shape and amplitude (unilateral, bilateral, multifocal).

Treatment of symptomatic and cryptogenic focal epilepsies of infancy requires maximum activity. Unfortunately, the range of anticonvulsants approved in Russia for use in young children and available (valproate, carbamazepine, barbiturates, benzodiazepines) is insufficient.

The use of the drug Trileptal®, the use of which is allowed for children from the age of 1 month, makes a significant contribution to the treatment of focal epilepsies of infancy. The recommended initial daily dose is 8-10 mg/kg (divided into 2 doses), the titration rate is 10 mg/kg per week, the maximum daily dose is 55-60 mg/kg. Convenient for administration to young children is an oral suspension (60 mg/ml, 250 ml in a bottle).

We have obtained our own positive clinical experience of using trileptal suspension in young children with focal epilepsy. During 2009 In the early childhood department of the CSCH No. 1, 73 children with epilepsy were treated. 15 children with partial epileptic seizures (20.5%) were prescribed Trileptal with dose adjustment, then therapy was recommended to take home. The children's ages ranged from 1 to 13 months.

In 1 observation, partial epilepsy was regarded as cryptogenic, and the child was prescribed Trileptal monotherapy.

14 patients had symptomatic forms of epilepsy. In 11 cases, these were symptomatic partial epilepsies against the background of severe or moderate perinatal brain damage, most often of hypoxic origin. The clinical picture included simple partial motor seizures, versive, oculomotor seizures, and tonic spasms. During EEG video monitoring, regional epileptiform activity was recorded.

In 3 patients, epileptic encephalopathies were detected against the background of cerebral dysgenesis (lissencephaly, agyria - 2 cases) and tuberous sclerosis (1 case). There was significant delay in motor and mental development. Epilepsy manifested itself as infantile spasms with a focal component - a version of the head, torso, freezing, and rolling eyes. During EEG-VM, multiregional or diffuse epileptiform activity was recorded.

All 14 patients received a combination of depakine and trileptal (suspension) 30-40 mg/kg. In all observations, a decrease in the frequency of attacks and good tolerability of therapy were noted.

ASSESSMENT OF SPATIAL SYNCHRONIZATION OF BIOELECTRICAL PROCESSES OF THE BRAIN BY BIPOLAR EEG LEADS AND ITS IMPORTANCE FOR PREDICTION OF SURGICAL TREATMENT OF EPILEPSY
Pestryaev V.A.,* Lavrova S.A.,** Zolotukhina A.R.,* Rastyagaeva O.L.*
*Department of Normal Physiology, USMA,

**Sverdlovsk Regional Oncology Center, Yekaterinburg
Purpose of the work: to create an indicator of the state of processes of spatial synchronization of bioelectrical activity of the brain (BEA GM) based on the analysis of EEG spectra of bipolar leads and to study the possibility of its use to assess the risks of developing epileptization of brain tissue during the surgical treatment of epilepsy.

Group 1 consisted of 32 patients with frontal and frontotemporal forms of epilepsy after surgical treatment of epilepsy (patients with positive (75% reduction in the frequency of attacks) and negative outcomes, and patients with right- and left-sided localization of the pathological focus were separately analyzed. Group 2 consisted of 24 healthy student volunteers. Based on the power spectra of bipolar EEG leads that do not have common points, correlation coefficients between the spectra of their harmonics were calculated, which, by analogy with the coefficients of cross-correlation analysis, were called similarity coefficients (CS). in the studied groups was observed for the CS calculated between leads F3-F7/C3-T3 and C3-T3/T5-P3 in the left hemisphere and F4-F8/C4-T4 and C4-T4/T6-P4 in the right hemisphere, respectively. between these leads and were further considered as particular characteristics (CS 1 and CS 2) of the state of spatial synchronization of the BEA GM, especially since we were talking about symmetrical leads of the left and right hemispheres. The use of two particular indicators of the state of spatial synchronization of the BEA GM for each hemisphere, which have approximately the same information value, but not the same values, required a reasonable compromise between them - the introduction of a generalized indicator. As such a generalized indicator of the state of spatial synchronization (SPS) of the BEA GM, the norm of the vector was calculated, the coordinates of which were partial indicators: SPS = (KS 1 2 + KS 2 2) 1/2, i.e. - square root of the sum of squares of partial indicators.

In group 2, all SPS values ​​for both hemispheres were less than 1 (average values ​​- 0.80 for the left hemisphere and 0.84 for the right), and after GW the tendency towards their decrease prevailed (0.79 for the left hemisphere and 0.80 for right). In group 1, the average SPS indicators, especially in the hemisphere of the lesion localization, were significantly increased - 1.03 in the left hemisphere with left-sided localization of the lesion and 0.97 in the right hemisphere with right-sided localization. After GV, the prevailing tendency was for their further increase - 1.09 in the left hemisphere with left-sided localization of the lesion and 1.06 in the right hemisphere with right-sided localization.

In the hemisphere contralateral to the lesion, along with increased values ​​of the SPS indicator after breastfeeding, there was a sufficient number of cases with normal values ​​of SPS (less than 1), characteristic of the control group with clearly normal functioning of the mechanisms regulating the spatial synchronization of the BEA GM. This made it possible to consider the value of the SPS indicator after GV in the hemisphere opposite to the localization of the focus of pathological activity as a criterion for the state of the regulatory mechanisms of spatial synchronization of BEA GM: exceeding 1 is a sign of a risk factor contributing to the development of further postoperative epilepsy of brain tissue. Comparative probabilistic analysis showed that in the presence of this sign, the relative risk of lack of a positive effect from surgical intervention increases by 2.5 times.

Epileptic seizures or dystonic attacks, difficulties in differential diagnosis
Rakhmanina O. A., Levitina E. V.

GOU VPO Tyumen State Medical Academy of Roszdrav

GLPU TO Regional Clinical Hospital No. 2

Tyumen
9 children (6 boys and 3 girls) with generalized symptomatic dystonia were examined. The distribution of children by age was as follows: 3 children under the age of 1 year, 3 children - from 1 to 2 years, 1 child each - 3 and 4 years old, and 1 child 8 years old. An analysis of the causes of dystonia showed that 8 of these children had severe perinatal damage to the central nervous system with subsequent development of cerebral palsy, and 1 child had a chromosomal abnormality (deletion of the short arm of chromosome 5). All children had pathology of the antenatal period in the form of: gestosis (3), threat of miscarriage (4), intrauterine infection (3), polyhydramnios (1), chronic fetoplacental insufficiency (1), anemia (4) and frequent acute respiratory viral infections with fever in mothers (1). All these factors led to a pathological course of the intrapartum period: acute asphyxia (5), prematurity (2), intracranial birth injury (1), intraventricular hemorrhage (2), while delivery was carried out by cesarean section only in 2 cases. All children had a severe course of the early neonatal period: in 5 - artificial ventilation (14.6±11.3 days), convulsive syndrome (3), meningoencephalitis (2), sepsis (1), anoxic cerebral edema (1) . During this period, 1 child suffered a severe traumatic brain injury, brain contusion with subarachnoid hemorrhage. CT/MRI of the brain revealed multiple structural defects: hydrocephalus (4 children, 2 of them with HPS); porencephalic cysts (3); periventricular leukomalacia (2); total subcortical leukomalacia – 1; cerebellar hypogenesis, Dandy-Walker anomaly (1), lobe atrophy (2), vascular malformation (1); cerebral dysgenesis (1). A child with a chromosomal abnormality had malformations of other organs (congenital heart disease, hydronephrosis, thymomegaly). A similar pattern of attacks allowed us to suspect dystonic attacks in all 9 children: “arching” sometimes with a torsion component, opening the mouth, sticking out the tongue. Consciousness is not lost, often a painful reaction in the form of a cry and provocation by a change in body position or touch during examination. Clinically, six of the 9 children had previously been diagnosed with epilepsy and had been unsuccessfully selected for antiepileptic treatment. When we conducted video-EEG monitoring at the time of the attack, these children did not reveal epileptiform activity. 3 children actually suffered from epilepsy in parallel: West syndrome (2), symptomatic focal epilepsy (1). At the same time, in 2 patients with remission of seizures within 1 year and at the time of the onset of the above-described conditions, the issue of recurrence of epileptic seizures or the appearance of dystonia was resolved. In 1 child, single flexor spasms persisted, which simplified the diagnosis of dystonia on the one hand; on the other hand, the question arose about the transformation of West syndrome into focal epilepsy. When conducting video-EEG monitoring at the time of dystonia, these 3 children also had no epileptiform activity. All 9 children were added to antidystonic therapy (Nacom, clonazepam, baclofen, Mydocalm) with a partial or significant positive effect. Thus, symptomatic dystonia in children was more common under the age of 4 years. With them, young children experience a combined effect of several pathological factors leading to severe damage to the central nervous system. Carrying out differential diagnosis of dystonia using video-EEG monitoring is necessary to ensure appropriate treatment for this category of patients.
ELECTROENCEPHALOGRAPHIC PATTERN OF BENIGN EPILEPTIFORM DISORDERS OF CHILDHOOD IN CHILDREN WITH SEVERE SPEECH IMPAIRMENTS
Sagutdinova E.Sh., Perunova N.Yu., Stepanenko D.G.
GUZ SO, DKBVL, “Scientific and Practical Center Bonum”, Yekaterinburg
Objective: To clarify the frequency of occurrence and main characteristics of the electroencephalographic pattern of benign epileptiform disorders of childhood (BED) in children with severe speech disorders without epileptic seizures.

Materials and methods: The study involved 63 children aged from 2 years 10 months to 4 years 6 months with severe impairments of expressive speech (OSD level 1), who had perinatal hypoxic-ischemic encephalopathy and did not currently have or have a history of epileptic seizures. Children with speech impairments due to severe neurological, mental, somatic diseases, genetic syndromes and hearing impairment were excluded from the study. All children underwent one-hour video EEG monitoring in a state of wakefulness and natural sleep on a Comet electroencephalograph (Grass-Telefactor, USA). Using visual assessment of EEG and video material, the presence and main characteristics of epileptiform activity were analyzed.

Results and discussion: The electroencephalographic pattern of benign epileptiform disorders of childhood was exclusively subclinical in nature and was recorded in 12 children (19%). Thus, the frequency of its occurrence among children with severe expressive speech disorders significantly exceeds the general population indicator, which, according to various authors, is 1.9-4%. During wakefulness and sleep, the DND pattern was recorded in 8 children (66.6%). An increase in the index of epileptiform activity during the transition from wakefulness to sleep was observed in only one child (8.3%). In 4 children (33.4%), this pattern was recorded only in the sleep state. Children with severe speech impairments were characterized by bilateral localization of the DND pattern (8 children, 66.6%), unilateral, predominantly left-sided localization was noted only in 4 patients (33.4%). The vast majority of children had a low or moderate index of epileptiform activity (11 children, 91.7%), and only one child (8.3%) had an index rated as high. The predominant localization of the DEND pattern was observed in the central-temporal regions of the brain (8 children, 66.6%), localization only in the central regions was observed in 2 children (16.7%) and with the same frequency this pattern was recorded in the temporo-parietal areas of the brain (2 children, 16.7%).

Conclusions: Thus, children with severe speech impairments are characterized by a higher frequency of occurrence of the subclinical electroencephalographic pattern DEND with a predominant bilateral localization in the central-temporal regions of the brain, with a low or medium index, than in the general population, without a significant increase in the sleep index. Considering the presence of a proven genetic predisposition, which manifests itself in the form of impaired maturation of neurons in the cerebral cortex, both during the formation of the DED pattern and in primary speech disorders in children, we can assume some commonality in the genetic mechanisms of these pathological conditions. Further prospective studies are needed to evaluate the impact of the subclinical electroencephalographic pattern of DEND on the course and outcome of speech disorders, the risk of developing epilepsy and the need for antiepileptic therapy in children with severe speech disorders.

PRACTICAL ASPECTS OF THE WORK OF THE CHILDREN'S CITY EPILEPTOLOGICAL CENTER OF THE CITY OF KAZAN
Sivkova S.N., Zaikova F.M.

Over the last decade, much attention has been paid to the creation of a specialized epileptological service for children and adolescents in different regions of Russia. The Republic of Tatarstan was no exception. In 2000, a room for the diagnosis and treatment of epilepsy and paroxysmal conditions was organized at the Children's City Hospital 8. The office has become the most important link in the organization of medical care for children suffering from epilepsy in Kazan.

Purpose of the work: to show the practical experience of the office in providing specialized advisory assistance to children with epilepsy.

Methods: Compare data from the practical work of the children's city epileptological service in the city of Kazan in 2000 and 2009.

Results obtained: In 2000, all patients registered in the office were divided into only two epilepsy groups, depending on the type of epileptic seizure: epilepsy with Grand mal seizures - 89.6% and epilepsy with Petit mal seizures - 10 .4%. The group of patients with focal forms of epilepsy was not identified then. At that time, the leading position in treatment was occupied by phenobarbital - 51%; carbamazepine – 24%; valproic acid preparations – 18%. New generation drugs have not yet been used in therapy.

In 2009, the situation changed dramatically. 889 children with epilepsy observed in an epileptology office were divided into main groups according to forms of epilepsy, according to the 1989 International Classification of Epilepsies and Paroxysmal Conditions. The data are displayed as follows: idiopathic focal forms accounted for 8%; idiopathic generalized – 20%; symptomatic focal – 32%; symptomatic generalized – 8%; presumably symptomatic (cryptogenic) focal – 29%; undifferentiated – 3%. The range of antiepileptic drugs used has also changed in accordance with global trends in the field of epileptology. Currently, valproic acid preparations are used more often - 62%; carbamazepines 12%. The group of new antiepileptic drugs included: topiramate – 12%; lamotrigine – 3%; keppra – 5%; trileptal – 3%. The proportion of patients receiving phenobarbital therapy decreased significantly to 1.5%. The overwhelming number of patients are treated with monotherapy – 78%. 16% of patients receive 2 antiepileptic drugs. Clinical remission was achieved in 72% of children. Attacks continue despite regular treatment in 17% of cases. Most often, this group consists of patients with focal forms of epilepsy who are on combination therapy with several drugs. 3% of patients report irregular use of antiepileptic drugs.

Conclusions: monitoring patients in a specialized epilepsy center makes it possible to correctly diagnose a specific form of epilepsy in each specific case, prescribe adequate antiepileptic therapy in accordance with international standards for the treatment of epilepsy, increases the effectiveness of epilepsy treatment and, accordingly, improves the quality of life of patients and their families.

TREATMENT OF FOCAL FORMS OF EPILEPSY IN CHILDREN WITH ANTI-EPILEPTIC DRUGS

DIFFERENT GENERATIONS
Sivkova S.N., Zaikova F.M.
MUZ "Children's City Hospital 8", Kazan
Modern antiepileptic therapy can achieve an effect in the treatment of epilepsy in 70-80% of patients. However, 20-30% of children continue to have epileptic seizures. The use of drugs of different pharmacological groups and generations makes it possible to prescribe the most effective treatment both in monotherapy and in combination of several antiepileptic drugs.

The purpose of this work is to demonstrate the comparative effectiveness and tolerability of topiramate, lamotrigine and phenobarbital in the treatment of focal forms of epilepsy in children.

Materials and methods. The study included three groups of patients aged from 6 months to 17 years, with symptomatic focal forms of epilepsy - 79 people (82%) and presumably symptomatic (cryptogenic) focal forms of epilepsy - 17 people (18%). Patients received treatment with phenobarbital group drugs (34 patients) at a dose of 1.5 to 12 mg/kg/day; topiramate (31 patients) at a dose of 2.8 to 17 mg/kg/day and lamotrigine (31 patients) at a dose of 0.5 to 6 mg/kg/day.

Results obtained. A positive effect in treatment (complete relief of attacks or a reduction in their frequency by 50% or more) was achieved in 27 (87%) receiving topiramate; in 22 (71%) patients receiving lamotrigine and in 13 (38%) patients receiving phenobarbital. Topiramate showed no significant difference when used at either low doses (78%) or high doses (83%). Lamotrigine was more effective at doses greater than 3 mg/kg/day (78%) versus lower doses (62%). Higher efficacy of phenobarbital was observed at doses less than 5 mg/kg/day (59%) compared with higher doses (42%).

Side effects were reported in 16 patients (52%) receiving topiramate. Of these, aggravation of attacks was noted in 1 case (3%). In this case, the drug was discontinued. Other undesirable effects included the appearance of salts in the urine, lethargy, drowsiness, and decreased appetite. In the group of patients receiving lamotrigine, adverse effects were noted in 10 patients (32%). Of these, in 2 cases (6%) an allergic reaction was observed in the form of pinpoint rash and angioedema, and in 2 cases (6%) an increase in attacks was recorded; Because of this, the drug was discontinued. In patients receiving phenobarbital therapy, side effects were observed in 16 patients (47%) and were more often associated with the effect of the drug on cognitive functions (aggression, irascibility, disinhibition, drowsiness, fatigue).

Conclusions. New generation antiepileptic drugs (topiramate and lamotrigine) have shown greater effectiveness and good tolerability compared to phenobarbital in the treatment of focal forms of epilepsy in children of different age ranges. Thus, rational antiepileptic therapy will reduce both the number of seizures in children with epilepsy and the level of side effects traditionally observed when prescribing outdated antiepileptic drugs.

USE OF TRILEPTAL IN PATIENTS WITH RESISTANT FOCAL EPILEPSY
Sorokova E.V.
Antiepileptic Center of Municipal Clinical Hospital No. 40, Ekaterinburg
The study group included 25 patients aged 18 to 38 years with resistant temporal lobe epilepsy, observed at the Antiepileptic Center of City Clinical Hospital No. 40 in Yekaterinburg. Of these, 13 patients were diagnosed with mesial temporal sclerosis, the rest were observed with cryptogenic forms. The frequency of attacks ranged from 8 per month to 10 per day; focal attacks predominated in the clinic - in 14 patients, in the rest - in combination with secondary generalized ones.

It should be noted that all patients were diagnosed with a resistant form, since all received polytherapy with anticovulsants in high therapeutic dosages; 2 patients underwent surgical intervention.

15 patients were transferred to monotherapy with trileptal in doses of 2400-2700 mg/day, the rest received a combination of trileptal with finlepsin or carbamazepine.

During EEG monitoring, regional epileptiform activity was recorded in 10 patients, and with secondary generalization in 8 patients.

Catamnesis averages 1.5 years. Remission occurred in 8 patients, 8 of whom took only Trileptal. Significant improvement (reduction of attacks by more than 75%) – in 11 patients. Trileptal was discontinued in 1 patient due to the appearance of a rash. In general, the drug was well tolerated, and 5 patients remained on the same therapy even in the absence of a significant reduction in the number of attacks. 10 patients noted a decrease in irritability, tearfulness, anxiety, and improved sleep and mood while taking trileptal. Blood tests showed a clinically insignificant decrease in hemoglobin in 2 patients. The absence of epileptiform changes in the dynamics of the EEG was noted in 7 patients, in 2 - positive dynamics in the form of a decrease in epileptiform activity. Thus, in case of resistant temporal lobe epilepsy, Trileptal has established itself as a highly effective anticonvulsant with good tolerability and a pronounced normothimic effect; combination with other carbamazepines is possible and also clinically successful.

ON THE ISSUE OF IMPROVING DISPENSARY OBSERVATION OF PATIENTS WITH EPILEPSY AND PAROXYSMAL CONDITIONS

Sulimov A.V.
MU Children's City Clinical Hospital No. 9, Ekaterinburg
Epilepsy is one of the most common brain diseases. According to the results of numerous studies by neurologists and psychiatrists, the disease is detected much more often in children than in adults. About 70% of all forms of epilepsy begin in childhood. Thus, epilepsy can be considered a childhood disease, and, given the polymorphism of the disease, a number of authors use the definition - childhood epilepsy.

A fairly widely accepted point of view is that the younger the child is at the time of seizures, the more pronounced the hereditary predisposition. The onset of the disease sometimes occurs unexpectedly for the patient and his environment at any age, even in the presence of factors affecting the central nervous system in fairly distant age periods.

When collecting an anamnesis, the life characteristics of both the patient himself and his relatives, the so-called risk factors for the development of various pathologies, are revealed. The study of epilepsy in children allows us to find out in more detail than in adults the course and type of seizure and the dynamics of the development of the disease. Among the identified conditions preceding the onset of epilepsy, special emphasis is placed on the presence of diseases of the “epileptic circle”: affective-respiratory attacks, fainting, stuttering, febrile seizures, sleepwalking, abdominal colic, etc. The very concept of “diseases of the epileptic circle” is ambiguously accepted by researchers in epileptology , but practitioners identify patients with these conditions from the general population as a risk group.

A number of works (V.T. Miridonov 1988,1989,1994) have identified two variants of the development of epilepsy in children. The first is characterized by the onset of the disease with the appearance of an epileptic seizure, the second option involves the onset of epileptic seizures to replace non-epileptic paroxysms. According to the authors’ observations, two-thirds of observations correspond to the traditional variant and one-third corresponds to the development of the disease according to the “second” type. Noting the role of hereditary factors in the occurrence of epileptic seizures, emphasis is constantly placed on the fact that when analyzing the health status of relatives in patients with various variants of the development of the disease, 1/3 revealed indications of paroxysmal conditions, both in the first and second groups.

Epilepsy lasts on average about 10 years, although for many the period of active seizures is significantly shorter (less than 2 years in more than 50%). A significant number (20-30%) of patients suffer from epilepsy throughout their lives. The nature of attacks is usually determined at the initial stage of their onset, and this, along with other prognostic factors, makes it possible to provide fairly high accuracy in predicting the outcome of the disease within several years after its onset. At the same time, transformation of seizures in children is acceptable as the brain “matures,” with a decrease in the process of growth in the tendency to generalize. This primarily affects generalized tonic-clonic seizures; their differentiation into primary and secondary generalized ones can be carried out after long-term observation of patients. In these clinical cases, neurophysiological and intrascopic research methods occupy a significant place.

Electroencephalography (EEG) occupies a leading place among neurophysiological methods. EEG allows not only to differentiate the form of a seizure, to establish the localization of the epileptic focus, but also to determine the effectiveness of drug therapy and routine measures. The introduction of “routine” EEG into everyday medical practice, not to mention EEG monitoring, makes it possible to evaluate the reaction of the child’s brain to the course of the disease over time.

Of the intrascopic diagnostic methods that allow intravital visualization of the brain, neurosonography, computed tomography and magnetic resonance imaging come to the fore.

Brain imaging is performed for the following purposes:

a) determining the etiology of the disease;
b) predetermination of the forecast;
c) providing patients with knowledge about their own illness;
d) determination of genetic recommendations;
e) providing assistance in planning the operation.

According to various authors, the introduction of neuroimaging methods has changed the ratio of symptomatic and idiopathic forms of epilepsy in favor of the former. All this suggests that a number of terms used in modern classifications will be dynamically revised, with the introduction of new diagnostic technologies into practice. Changes in approaches to the formulation of diagnosis and treatment tactics will change both the duration and principles of dispensary observation of patients with epilepsy at different age periods.

The introduction of modern diagnostic technologies into practice in combination with traditional methods makes it possible to identify children at risk for the development of epilepsy. Excluding, in everyday life, situations that provoke the development of the disease: overheating, lack of sleep, intense physical activity and conducting dynamic monitoring of the results of neurophysiological research methods with minimal drug correction will reduce the risk of developing the disease. This setting is most relevant in pediatric neurology, since emerging current issues of preventive vaccinations and visits to children's groups should have uniform approaches from doctors of various specialties.

In Yekaterinburg since 1996 a specialized appointment with a pediatric neurologist was organized for patients with epilepsy and paroxysmal conditions on the basis of the advisory clinic of the children's city clinical hospital No. 9. Over time, the diagnostic capabilities of the consultant expanded, but this also expanded the range of tasks assigned to this specialist. Solving medical, methodological, and expert issues by an epileptologist allows one to prolong the remission of the disease in patients. At the end of 2009 the dispensary group of patients with epilepsy (age up to 18 years) in Yekaterinburg amounted to 1200 people, the dispensary group “non-epileptic paroxysms” - 800. This differentiated approach to patients with paroxysmal conditions was introduced in 2005, this made it possible to have a clearer picture in the structure of overall morbidity, so and the number of disabled children. This greatly facilitated the solution to the issue of providing patients with antiepileptic drugs and made it possible to solve a wide range of social problems.

Clinical-electrophysiological and

neuropsychological characteristics of patients

with epileptic encephalopathies and

symptomatic focal epilepsy

from DEPD to EEG
Tomenko T.R. ,* Perunova N.Yu. **
*OGUZ SOKPB Children's Mental Health Center

**Regional Children's Center for Epilepsy and Paroxysmal Conditions

Regional Children's Clinical Hospital No. 1

Ekaterinburg
Purpose of the work: to conduct a comparative analysis of clinical, electroencephalographic disorders and features of higher mental functions in children with epileptic encephalopathies and symptomatic focal epilepsy with benign epileptiform patterns of childhood (BEPD) on the EEG to determine the specificity and prognostic significance of this type of epileptiform activity.

Materials and methods: 29 patients with various forms of epilepsy were examined: 12 children with pseudolennox syndrome (PLS), 8 with epilepsy with electrical status epilepticus of slow-wave sleep (EESM) and 9 with symptomatic focal epilepsy (SFE).

The study included an assessment of clinical, genealogical, neurological, neurophysiological and neuroradiological data. Children aged 7 years and older underwent neuropsychological testing using a modified method of neuropsychological diagnosis and correction for developmental disorders of higher mental functions (Skvortsov I.A., Adashinskaya G.I., Nefedova I.V., 2000). The speech therapist assessed the patients' school skills (writing, reading and arithmetic). Patients with moderate to severe mental retardation were excluded from the neuropsychological examination. To determine the level of intelligence using D. Wexler's method (children's version), the children were tested by a psychologist. Patients with cognitive and behavioral disorders were examined by a psychiatrist.

To determine the index of epileptiform activity (EA), an algorithm for digitizing graphic elements was developed using Microsoft Excel. We took values ​​up to 29% as a low EA index, values ​​from 30-59% as average, and a high index of epileptiform activity corresponded to a value of more than 60%. The latter value, in our opinion, was characterized by the term “continued epileptiform activity”, since a high representation of DEPD was noted at all recording epochs, reaching up to 100% in some of them during slow-wave sleep.

Results: The study revealed that in symptomatic focal epilepsy with DEPD, the EEG showed exclusively motor focal and secondary generalized seizures associated with the sleep-wake cycle, of low and medium frequency (from several episodes per year to 1 time per week). Epileptiform activity during sleep was predominantly unilateral or bilateral independent (66%). The epiactivity index of wakefulness and sleep corresponded to low and average values ​​(up to 60%). The prognosis for the course of epilepsy in relation to seizures was favorable - remission or a reduction in the frequency of seizures by 75% was achieved in all patients on an average dose of monotherapy. However, these patients had a complicated obstetric history, severe cognitive deficits (88%) and delayed motor development (75%) (p

We made comparisons between the character, epiactivity index, neurological status, morphological changes in the brain and level of intelligence in patients with epileptic encephalopathies and symptomatic focal epilepsy. It turned out that in patients, bilateral bilateral synchronous epileptiform activity during wakefulness was significantly more likely to take on a continued diffuse character during sleep (p

Patients with focal neurological symptoms were significantly more likely to have a high EA index (more than 60%) during sleep, compared to patients with diffuse neurological symptoms (p

Among patients with mental retardation, significantly more often (p

According to the data obtained, there was no relationship between the EA index and the level of intelligence. Thus, patients with a normal level of intelligence had an average value of the EA index in sleep (49.4±31.1%), with a borderline level - (49.6±31.7%), and children with a low level - (52.2±33 ,9%).

According to CT and MRI data, 75% of patients in this group showed structural changes in the brain in the form of internal and external hydrocephalus, arachnoid cysts of the temporal and parietal lobes, asymmetric expansion of the lateral ventricles, cysts of the septum pellucidum and myeloradiculomeningocele. The presence of morphological changes in the brain in children with epileptic encephalopathies and symptomatic focal epilepsy contributed to the bilateral spread of epileptiform activity during sleep (p

During antiepileptic therapy, 14 (56%) patients showed positive dynamics in the form of remission or reduction in seizures by 75%. Of these, 5 patients with symptomatic focal epilepsy achieved remission with valproate monotherapy. However, despite the positive dynamics regarding seizures, a decrease in the EA index according to EEG video monitoring was observed in only 4 patients. All children continued to have cognitive and behavioral impairments.

Using neuropsychological techniques, 12 children were tested: with pseudolennox syndrome (6), epilepsy with electrical status epilepticus of slow-wave sleep (2) and symptomatic focal epilepsy (4) with an equal distribution by gender, aged 7 to 11 years. In half of the children examined, disorders of all higher mental functions were identified to varying degrees. The highest percentage of errors was observed in tests for kinesthetic (100%), spatial (100%), dynamic (92%) praxis, visual gnosis (100%), visual (92%) and auditory-speech memory (92%), and in subtest “drawing” (100%). Academic skills suffered significantly: reading in 80%, counting in 60%, writing in 80%.

According to the topical localization of higher mental functions, in patients with epileptic encephalopathies and symptomatic focal epilepsy, functional deficiency of the left hemisphere was observed to the greatest extent (p

Thus, the lateralization of the zone of functional neuropsychological defect and epiactivity coincided. No match in terms of topical localization was obtained.

According to the results of the D. Wexler test, 4 of the examined patients had normal intelligence, 4 had borderline intelligence, and 4 had mild mental retardation. Patients were divided by level of intelligence and compared by the number of incorrectly performed neuropsychological tests. Children with borderline intelligence and mental retardation made significantly more errors, compared with patients with a normal level of intelligence, in the following tests: visual gnosis (p

Thus, the factors influencing the neuropsychological profile of patients with pseudolennox syndrome, epilepsy with electrical status epilepticus of slow-wave sleep and symptomatic focal epilepsy are the level of intelligence, the presence of a history of delayed motor and speech development.

TACTICS OF SURGICAL TREATMENT OF PATIENTS WITH SYMPTOMATIC EPILEPSY WITH SERIAL AND STATUS COURSE OF SEIZURES

Shershever A.S.,* Lavrova S.A.,* Cherkasov G.V.,* Sorokova E.V.**

*GBUZ SO "Sverdlovsk Regional Oncology Center", Ural Interterritorial Neurosurgical Center named after. prof. D.G. Schaefer.

* City Clinical Hospital No. 40, Ekaterinburg
Any neurosurgical intervention, the main goal of which is to reduce epileptic seizures, can be regarded as surgical treatment of epilepsy.

Surgical operations (examples): excision of epileptogenic brain tissue, cortical topectomy, lobectomy, multilobectomy, hemispherectomy, and certain operations such as amygdala-hippocampectomy; callosotomy and functional stereotactic intervention; other functional procedures such as multiple dissection under the pia mater.

Based on our experience in surgical treatment of more than 1000 patients with epilepsy over the period 1964-2009. an algorithm for the intraoperative period was developed.

In the operating room, an EEG is recorded before the start of anesthesia.

Under general anesthesia, a scalp EEG is performed before the procedure begins. A compromise that suits the neurosurgeon, anesthesiologist and neurophysiologist is the III EEG stage of anesthesia according to Courtin.

EEG + ECoG is performed before the start of resection or stereotactic destruction of the conduction pathways of the epileptic system.

If the ECoG data coincides with the data on the localization of epileptogenic foci, a staged ECoG is performed with resection of the foci, or multiple subpial transsection, or stereotactic destruction - stimulation of each target point through the inserted electrode with EEG recording.

If there is a threat of kindling development, it is necessary to deepen anesthesia to level IV - VI EEG stage of anesthesia according to Courtin.

The results were encouraging. The effectiveness of surgical treatment in combination with antiepileptic therapy was higher in patients with resistant epilepsy than in those receiving only conservative therapy.

Epidemiology and risk factors for paroxysmal conditions
Yakhina F.F.
Consultative and diagnostic office for epilepsy and paroxysmal conditions, Kazan
The two main causes of episodic loss of consciousness are syncope and epilepsy. In order to establish their prevalence and pathogenetic connection with various diseases, a clinical and epidemiological study of the unorganized population of Kazan was carried out. 1000 (men - 416, women - 584) people aged 15-89 years were examined. During the door-to-door examination, various studies were taken into account (general and biochemical blood and urine tests; ECG; Dopplerography of the vessels of the brain, heart and extremities; fundus of the eye; ECHO, EEG; MRI/CT, ​​etc.). To determine the vegetative status, a questionnaire with a score was used [Vein A.M., 1988].

The material was processed on an IBM PC 486 computer using the Paradox database and the statistical software package Statgraf (Statistical Graphics System).

It was found that epilepsy in adults in the general population of Kazan occurred in 0.5%. Tonic-clonic seizures occurred 1.5-2 years after severe traumatic brain injury in the parietal region in persons with a depressed fracture and plastic surgery. Moreover, all registered were men aged from 50 to 89 years. Presyncope and syncope were noted in 15.3% and occurred in a wide age range from 15 to 89 years. In this subgroup there were more women than men by 1.4 times.

Various diseases and borderline conditions in people with epilepsy did not differ from those in the general population (p>0.05). All patients had severe neurological deficits, and autonomic disorders occurred with the same frequency as in the general population (60% and 56.0%, respectively). In the comparison group, the likelihood of developing presyncope/syncope increases in the presence of cardiovascular, pulmonary and genitourinary diseases, neurological and endocrine pathology, and increased meteosensitivity. In epilepsy there is no such dependence.

It can be concluded that in the general population of Kazan, epilepsy in adults is registered in 0.5%, and fainting in 15.3%. Among patients with epilepsy, men predominate, and among those with syncope, women predominate. Epilepsy is more common in people over 50 years of age. Fainting can occur at any age, and the likelihood of their occurrence increases in the presence of somatic pathology.
APPLICATION
HISTORY OF STUDYING EPILEPSY AND DEVELOPMENT OF CARE FOR PATIENTS WITH EPILEPSY IN SVERDLOVSK-YEKATERINBURG
Shershever A.S., Perunova N.Yu.

The formation and development of neurosurgery in the Urals is directly related to the study of issues of surgical treatment of epilepsy. In the twenties, M.G. Polykovsky described the Kozhevnikov epilepsy syndrome for the first time in the Urals, and already in the thirties D.G. Schaeffer performed the first neurosurgical interventions for this disease. At that time, the Gorsley operation was most widely performed, and if at first the area of ​​those parts of the motor cortex that were related to the limb covered by hyperkinesis was routinely removed, then later EcoG was used to localize the epileptic focus.

Further study of the pathogenesis and clinical picture of this disease showed that damage to the motor cortex is not always the leading factor determining the clinical picture of epilepsy. It was found that thalamocortical reverberant connections are essential for the implementation of hyperkinesis and epileptic seizures. This served as the basis for stereotactic interventions on the ventrolateral nucleus of the visual thalamus (L.N. Nesterov).

During the Great Patriotic War and in the immediate post-war period, the clinic team paid a lot of attention to the surgical treatment of traumatic epilepsy (D.G. Shefer, M.F. Malkin, G.I. Ivanovsky). During these same years, the clinic dealt with the issues of hypothalamic epilepsy (D.G. Shefer, O.V. Grinkevich), and the clinic of epileptic seizures in brain tumors was studied (Yu.I. Belyaev). All these works created the prerequisites for further expansion of research on the problem of epilepsy surgery.

Since 1963, comprehensive work on the study of epilepsy began at the Department of Nervous Diseases and Neurosurgery of the Sverdlovsk State Medical Institute. At the Hospital of Veterans of the Patriotic War, where the department was then located, consultations were held, and research work was actively carried out.

In February 1977 By order of the Ministry of Health of the RSFSR No. 32m-2645-sh, an epileptological center was created in the neurosurgical clinic of City Clinical Hospital No. 40 (which has been the base of the Department of Nervous Diseases and Neurosurgery of the SSMI since 1974), later named the Sverdlovsk Regional Neurosurgical Antiepileptic Center (SONPEC).

With the opening of a permanent appointment with a neurologist-epileptologist in 1982. (Perunova N.Yu.) advisory assistance to patients with epilepsy became more accessible, 2.5-3 thousand consultations were carried out per year.

Since 1996 the organization of specialized epileptological appointments began - at the Children's Multidisciplinary Hospital No. 9 (1996, Panyukova I.V.), Regional Clinical Hospital No. 1 (1997, Shmeleva M.A., Tereshchuk M.A., Vagina M.A.) , Regional Children's Clinical Hospital No. 1 (1999, Rylova O.P., Zhukova T.A., Grechikhina A.I.), City Psychiatric Dispensary (2000, Danilova S.A., Baranova A.G.), Center for Mental Health of Children and Adolescents of the Regional Psychiatric Hospital (2006, Tomenko T.R.). At currently functioning receptions, 13-14 thousand qualified consultations can be carried out during the year for patients with epilepsy and paroxysmal conditions.

In 2002 in the neurological department of the CSCH No. 1, an EEG video monitoring room was organized, the first in the Ural region (Perunova N.Yu., Rylova O.P., Volodkevich A.V.). In 2004 On the same basis, the Regional Children's Center for Epilepsy and Paroxysmal Conditions was created (Safronova L.A., Perunova N.Yu.).

Conducting EEG of daytime and night sleep and EEG video monitoring for children and adults has also become available at other medical institutions: Scientific and Practical Rehabilitation Center "Bonum" (2005, Sagutdinova E.Sh.), Center for Mental Health of Children and Adolescents (2007, Tomenko T.R.).

Work to improve surgical approaches in the treatment of epilepsy continues at the Sverdlovsk Regional Oncology Center, the Ural Interterritorial Neurosurgical Center named after. prof. D.G. Schaefer. (Shershever A.S., Lavrova S.A., Sokolova O.V.).

The list of dissertations on the problem of epilepsy defended by specialists from Sverdlovsk-Ekaterinburg illustrates the above.

CANDIDATE DISSERTATIONS:

1. 
   Belyaev Yu.I. Epileptic seizures in a brain tumor clinic (1961)
2. 
   Ivanov E.V. Stereotactic method in the diagnosis and treatment of temporal lobe epilepsy (1969)
3. 
   Bein B.N. The importance of EEG activation in the diagnosis and surgical treatment of temporal lobe epilepsy (1972)
4. 
   Boreyko V.B. Mental disorders in indications and long-term results of surgical treatment of patients with temporal lobe epilepsy (1973)
5. 
   Myakotnykh V.S. Course of focal epilepsy (according to long-term follow-up) (1981)
6. 
   Nadezhdina M.V. Dynamics of focal epileptic activity in patients with temporal lobe epilepsy (1981)
7. 
   Klein A.V. Histological and ultrastructural changes in neurons and synapses in the epileptic focus in patients with temporal lobe epilepsy (1983
8. 
   Shershever A.S. Prognosis of epilepsy after operations on the temporal lobe (1984)

1. 
   Perunova N.Yu. Comparative assessment of variants of the course of the main forms of idiopathic generalized epilepsy (2001)
2. 
   Sorokova E.V. An integrated approach to the treatment of drug-resistant forms of partial epilepsy (2004)
3. 
   Tereshchuk M.A. Clinical features and quality of life of patients with cryptogenic partial and idiopathic forms of epilepsy (2004)
4. 
   Agafonova M.K. Features of the course of epilepsy in pregnant women (2005)
5. 
   Sulimov A.V. The influence of factors of the perinatal period on the development and course of partial epilepsy in school-age children (2006).
6. 
   Lavrova S.A. Electrophysiological criteria for predicting the results of stereotactic epilepsy surgery (2006)
7. 
   Koryakina O.V. Clinical and immunological features of the course of epileptic paroxysms in children and the rationale for immunocorrective therapy (2007)
8. 
   Tomenko T.R. Clinical, encephalographic and neuropsychological characteristics of children with benign epileptiform childhood patterns (2008)

DOCTORAL DISSERTATIONS:

1. Nesterov L.N. Clinic, issues of pathophysiology and surgical treatment of Kozhevnikov epilepsy and some diseases of the extrapyramidal system (1967)

2. Belyaev Yu.I. Clinic, diagnosis and surgical treatment of temporal lobe epilepsy (1970)

3. Scriabin V.V. Stereotactic surgery for focal epilepsy (1980)

4. 
   Bein B.N. Subclinical and clinical disorders of motor function in patients with epilepsy (1986)
5. 
   Myakotnykh V.S. Cardiovascular and neurological disorders in patients with initial epileptic manifestations (1992)

1. 
   Shershever A.S. Ways to optimize surgical treatment of drug-resistant epilepsy (2004)
2. 
   Perunova N.Yu. Improving the diagnosis and organization of medical care for idiopathic generalized forms of epilepsy (2005)

INFORMATION ABOUT THE NON-PROFIT PARTNERSHIP “EPILEPTOLOGISTS OF THE URAL”
The non-profit Partnership “Epileptologists of the Urals” was created on the initiative of a group of epileptologists from Yekaterinburg (decision on state registration dated October 16, 2009, main state registration number 1096600003830).

The goal of the Partnership in accordance with the concepts of the World League Against Epilepsy (ILAE), the International Bureau of Epilepsy (IBE), and the Global Company “Epilepsy from the Shadows” is comprehensive organizational and methodological assistance in the development of care for patients with epilepsy in the Ural region.

The subjects of activity of the NP "Epileptologists of the Urals" are: the formation and implementation of research programs on epilepsy in the region; creation and maintenance of the Partnership website; organizing and conducting thematic conferences, lectures, educational seminars; preparation and implementation of thematic scientific-methodological, educational and popular literature; support for the introduction into practice of modern methods of diagnosis, treatment, rehabilitation of patients with epilepsy; assistance in providing patients with epilepsy with quality medical care, including medications; promoting educational work on the problems of epilepsy, as well as the implementation of international agreements on problems related to treatment, social rehabilitation and improving the quality of life of patients with epilepsy; attracting the attention of government authorities and society as a whole to the problems of patients with epilepsy.

The meeting of founders elected Doctor of Medical Sciences to the Council of the NP “Epileptologists of the Urals”. Perunova N.Yu. (Chairman), Doctor of Medical Sciences Professor Shershever A.S., Ph.D. Sulimov A.V., Ph.D. Sorokova E.V., Ph.D. Tomenko T.R. (secretary).

NP "Epileptologists of the Urals" - address for correspondence:

620027, Ekaterinburg, Sverdlova st. 30-18.

M.t. 89028745390. E-mail: perun@ mail. ur. ru(Perunova Natalia Yurievna)

Email: epiur@ yandex. ru(Tomenko Tatyana Rafailovna)

N.A. Ermolenko 1, A.Yu. Ermakov 2, I.A. Buchneva 3

1 -Voronezh State Medical Academy named after. N.N. Burdenko;
2 -Moscow Research Institute of Pediatrics and Pediatric Surgery of Rosmedtekhnologii;
3 - Voronezh Regional Children's Clinical Hospital No. 1

The discovery of a new category of epilepsies arising from local cortical dysfunction, with regional epileptiform discharges on the EEG and a benign prognosis for seizure resolution, is considered the most interesting contribution to epileptology in the last 50 years (Fejerman N. et al., 2007). The electroencephalographic correlate of these states are age-dependent patterns, morphologically representing a three-phase electric dipole with a period of an acute wave of more than 70 ms, followed by a slow wave and constant activation during sleep (Panayiotopoulos C.P., 2005). EEG patterns, known in the literature as “rolandic spikes” (Lundberg S. et al., 2003) or “benign focal epileptiform discharges of childhood” (Panayiotopoulos C.P., 2005), tend to be grouped in series, and in some cases occupy a significant part EEG recordings, recording almost continuously. Despite the use of the word “benign” in the name of a single complex, continued activity of DERD patterns can be the cause of mental, communicative, cognitive, behavioral and social disorders in children. Long-term persistent focal or diffuse epileptiform activity in the form of DERD patterns with a high index of representation on the EEG during sleep causes a functional rupture of neuronal connections, has an adverse effect on brain development during the critical period of synaptogenesis and causes neuropsychological disorders, even in the absence of epileptic seizures (Zenkov L R., 2007; Aarts J., 1984; Gobbi G., 2002). Therefore, these conditions are diagnosed late and have a poor prognosis.

Purpose The present study was to determine the clinical and neurophysiological features of epilepsy in children associated with continued epileptiform activity during sleep, and approaches to the rational treatment of these conditions.

Patients and methods

A preliminary screening examination was carried out on 1862 children aged 2 to 18 years who were admitted to the specialized psychoneurological department of the State Healthcare Institution “VODKB No. 1” for epileptic seizures and diseases of the nervous system not accompanied by epileptic seizures in the period from 2004 to 2007.

The patients were examined using a clinical method, including examination of neurological status, neuropsychological testing using A.R. methods. Luria, Toulouse-Pieron and Wechsler tests, as well as video-EEG monitoring (for the purpose of long-term continuous recording of EEG and patient behavior). Video-EEG monitoring was carried out using a computer complex of an electroencephalograph-analyzer “Encephalan 9”, Medicom MTD, Taganrog using 19 channels according to the international “10–20” system and an additional polygraphic ECG channel. The duration of continuous recording varied from 4 to 8 hours. When recording epileptiform activity during sleep, the spike-wave saturation index (SWI/SWI) was calculated (Patry G. et al., 1971; Tassinari C.A. et al., 1982). Neuroradiological examination was carried out on a Siemens magnetic resonance imaging scanner (with a magnetic field voltage of 1.5 Tesla).

Results

During the examination, DERD were detected in the background EEG recording and during sleep in 229 (12.3%) patients, including 190 (22.6%) patients with a verified diagnosis of epilepsy (n=840) and 39 (3, 8%) patients with neurological pathology (n=1022), not accompanied by epileptic seizures (Table 1).

Table 1. Frequency of occurrence of EEG changes with the DERD pattern in patients with various nosological forms

In children with cerebral palsy (CP), epilepsy and brain malformations, EEG patterns of DERD were recorded in 10.3%, 22.6% and 52% of cases, respectively, which was 2–10 times higher than the general population values ​​(Panayiotopoulos C.P., 2005 ; Covanis A., 2009).

In patients with cerebral palsy, the hemiparetic form was found in 46% of cases, which significantly exceeds the general population frequency of occurrence of this form of cerebral palsy - up to 13% in the population of patients with cerebral palsy (Ermolenko N.A., 2006).

In 122 patients (53%), there was a combination of epileptic seizures and/or cognitive disorders with prolonged (diffuse or regional) epileptiform activity in the form of SERD patterns during slow-wave sleep (SWS), occupying from 30% to 100% of the recording epoch.

Based on neuroradiological examination data, all children with PEMS (n=122) were divided into 2 groups: the first group (group I; n=62) consisted of patients who had no structural changes in the brain and focal neurological symptoms - idiopathic option (ratio of girls and boys - 1.1:1); the second group (group II; n=60) included patients with focal structural changes in the brain and/or with focal neurological symptoms - symptomatic variant (ratio of girls to boys - 1:1.2).

In group II patients, various brain malformations were verified in 22% of cases; in 19% of patients arachnoid cysts were found in the area of ​​the lateral fissures, which are difficult to differentiate from polymicrogyria according to MRI (Alikhanov A.A., 2000), in 53.7% of cases atrophic changes were detected due to strokes, periventricular leukomalacia, and intrauterine infections; in 5.6% of patients, changes on MRI were not verified, but a pronounced neurological deficit was detected in combination with impaired development of cognitive functions. The ILAE Commission on Classification and Terminology (2001) recommends that these cases be treated as probably symptomatic (Engel J., 2001). No predominant localization of focal changes in brain regions was identified, but significantly more often (p<0,05) они обнаруживались в левой гемисфере по сравнению с правой (в 35,3% (n=18) и в 25,5% (n=13) случаев соответственно).

Based on the history, clinical course and results of video-EEG monitoring in patients with continued epileptiform activity during sleep (n=122), the following nosological forms were verified: benign focal epilepsy of childhood with central temporal spikes (18.9% ( n=23) cases); benign occipital epilepsy of childhood with early onset (4.8% (n=6) patients); symptomatic focal epilepsy (14.6% (n=18) of patients); epilepsy with electrical status epilepticus of slow-wave sleep (42.2% (n=52) of patients), including idiopathic (35% (n=18) and symptomatic (65% (n=34)) variants; epileptiform cognitive disintegration (17.1% (n=21) patients); Landau-Kleffner syndrome (1.6% (n=2) patients).

Normal background bioelectrical activity was significantly more often observed in patients of group I compared to group II (47% (n=29) and 20% (n=12), p<0,05 соответственно). В бодрствовании у пациентов в двух группах достоверно чаще регистрировалась региональная продолженная эпилептиформная активность с индексом от 15 до 85% (46% случаев) по сравнению с диффузной (24% больных), мультифокальной (20% пациентов) и унилатеральной (10% детей) активностью. У всех обследованных пациентов отмечалось усиление эпилептиформной активности во сне с появлением диффузной продолженной активности в 40% случаев и достоверным увеличением индекса эпилептиформной активности более 85% - у 41% пациентов, индексом 30–80% - у 59% больных.

Fronto-central-temporal regional accentuation of PEMS (77% (n=43) of patients) was recorded significantly more often (p<0,05), чем теменно-затылочная и затылочная (14% (n=8) пациентов), лобная (9% (n=5 случаев) и центрально-височная (5% (n=3) детей). В 5% (n=6) случаев было зарегистрировано перемещение (шифт) эпилептиформной активности из одной гемисферы в другую при последующих записях ЭЭГ, без достоверной разницы между группами I и II. Смещение региона в пределах одной гемисферы отмечалось в 6% (n=7) случаев. У 11,6% пациентов зарегистрировано несовпадение региональной продолженной эпилептиформной активности на ЭЭГ со стороной локализации очаговых структурных изменений в головном мозге, выявленных при нейровизуализации.

Cognitive disorders of varying severity were verified in 89% of patients included in the study. 11% of children had autistic behavior disorder without a significant difference between groups I and II (13% and 8%, respectively). Patients in group II were significantly more likely, compared to patients in group I, to have more severe cognitive disorders with total impairment of the development of all higher mental functions (60% and 24%, respectively, p<0,05), а также «преморбидная» задержка их формирования с раннего возраста (у 50%), с резким нарастанием когнитивного дефицита после появления эпилептических приступов и/или продолженной эпилептиформной активности на ЭЭГ.

Epileptic seizures were absent throughout the entire observation period in 24.6% (n=30) of patients. Patients in group I showed a predominance of focal motor seizures (100% compared to 61%, p<0,05), связанных со сном (78% против 41%, p<0,05). Однако гемиклонические (22% в сравнении с 11%, p<0,05) и вторично-генерализованные судорожные приступы (30% в сравнении с 9%, p<0,05) чаще отмечались у пациентов группы II (рис. 1) и достоверно чаще возникали в бодрствовании, по сравнению с больными группы I (35% в сравнении с 17%, p<0,05). Ингибиторные моторные эпизоды отмечались у 23% (n=21) детей, достоверно чаще у больных в группе I, чем в группе II (76% (n=16) и 24% (n=5) соответственно, p

It has been established that the long-term prognosis of the disease (3 years after the start of treatment) is determined by the following factors: duration of epileptiform activity, age of onset of the disease, severity of cognitive impairment before treatment and the effectiveness of antiepileptic therapy during the first year. The onset of the disease before 3 years of age, continued epileptiform activity during sleep that persists for more than 1 year, premorbid delay in the formation of cognitive functions, as well as the absence of clinical-electroencephalographic remission during the first year of therapy significantly worsen the prognosis of the disease. For such parameters as the frequency and nature of epileptic seizures, the nature and persistence of inhibitory symptoms, the index of epileptiform activity on the EEG during sleep and changes in MRI, no statistically significant relationship with the long-term prognosis of the disease was found.

Analysis of the effectiveness of antiepileptic therapy in the first year of treatment revealed a higher effectiveness of duotherapy compared to monotherapy, due to a significantly higher rate of achieving clinical electroencephalographic remission (23% compared to 12%, p<0,05). Наиболее эффективными оказались комбинации вальпроатов с этосуксимидом и леветирацетамом, при этом, клинико-электроэнцефалографическая ремиссия была достигнута в 30–75% случаев (табл. 2). В лечении эпилепсии с эпилептическим электрическим статусом медленного сна был наиболее эффективен леветирацетам: на фоне приема леветирацетама в монотерапии у всех детей (n=3) зарегистрирована клинико-электроэнцефалографическая ремиссия. Однако сопоставление данных по эффективности для сравнения с вальпроатами не представляется возможным из-за малого числа наблюдений.

In patients receiving carbamazepine (n=25) in initial monotherapy (n=16) and duotherapy (n=9), deterioration of the condition was noted in the form of aggravation and atypical evolution, followed by the formation of resistance to AEDs in 64% (n=16) cases.

Complete pharmaco-induced regression of continued epileptiform activity of DERD patterns was observed in 29% (n=35) of cases, 2 times more often in patients of group I - 37% (n=23) compared to patients of group II - 20% (n=12). The average age of disappearance of continued epileptiform activity of DERD patterns during treatment was 8.4–1.2 years, with no significant difference between groups I and II (8.3–1.6 and 8.7–1.7 years, respectively).

Table 2. Duotherapy in patients (n=52) with continued epileptiform activity in the form of EEG patterns on EEG during sleep

AEP	Number of children	Clinical remission	Clinical electroencephalographic remission	Lack of dynamics	Deterioration
Valproate + ethosuximide	31 (57%)	13 (42%)	9 (29%)	8 (26%)	1 (3%)
Valproate + levetiracetam	4 (7%)	1 (25%)	3 (75%)	-	-
Levetiracetam + topiramate	1 (2%)	1(100%)	-	-	-
Valproate + topiramate	6 (11%)	1 (17%)	-	5 (83%)	-
Carbamazepine + benzodiazepines	1 (2%)	1 (100%)	-	-	-
Valproate + benzodiazepines	1 (2%)	1 (100%)	-	-	-
Valproate + Carbamazepine	8 (15%)	-	-	1 (12,5%)	7 (87,5%)
Total	52 (100%)	18 (35%)	12 (23%)	14 (27%)	8 (15%)

Discussion

The electroencephalographic pattern of DERD, discovered for the first time in patients with rolandic epilepsy (Loiseau P. et al., 1961, 1967), was also detected in patients with various neurological pathologies; including in patients with symptomatic focal epilepsy, in whom structural changes in the brain in 41% of cases were localized in epileptogenic zones, and, thus, could be an independent source of epileptogenesis with the DERD pattern. The risk of epilepsy associated with PEMS in children with cerebral palsy, especially with hemiparetic forms, and brain malformations exceeds general population values ​​by 2–10 times. At the same time, in patients with a structural defect of the brain, “double pathology” cannot be excluded (Mukhin K.Yu., 2005), which is based on the universal mechanism of focal cortical dysfunction (Doose H. et al., 1989). A more benign course of idiopathic forms of epilepsy with the DERD pattern has been proven compared to symptomatic ones.

A five-year follow-up of patients with continued epileptiform activity of DERD patterns with an index of at least 30% during sleep showed evolution into epileptic encephalopathy in 66% of cases: in 49% of cases - into epilepsy with electrical status epilepticus in sleep and in 17% - into cognitive epileptiform disintegration. Thus, a spike-wave index of more than 30% on the sleep EEG in children, even without clinical manifestations of epileptic seizures, serves as an indication for the prescription of antiepileptic drugs.

It has been proven that initial therapy and the timing of its administration are crucial for the long-term prognosis regarding the preservation or restoration of cognitive functions in children and adolescents. The most effective are combinations of valproate with ethosuximide or levetiracetam in duotherapy.

Literature:

1. Alikhanov A.A. Methods of neuroimaging in the diagnosis of epilepsy in children // Epileptology of childhood: a guide for doctors / ed. A.S. Petrukhina. - M.: Medicine, 2000. - P. 407–501.
2. Duke V. Data processing on a PC in examples - St. Petersburg: Peter, 1997. - 240 p.
3. Ermolenko N.A. Variants of psychoneurological development in normal and pathological conditions in children of the first five years of life: abstract of thesis. dis. ...Dr. med. Sci. - Voronezh, 2006. - 47 p.
4. Mukhin K.Yu., Petrukhin A.S., Mironov M.B., Kholin A.A., Glukhova L.Yu., Pilia S.V., Volkova E.Yu., Golovteev A.L., Pylaeva O .A. Epilepsy with electrical status epilepticus of slow-wave sleep: diagnostic criteria, differential diagnosis and treatment approaches. - M., 2005. - 32 p.
5. Covanis A. Panayiotopoulos syndrome // Epilepsy in modern medicine: proceedings of the conference. - M., 2009. - P. 250–258.
6. Doose H., Baier W.K.. Benign partial epilepsy and related conditions: Multifactorial pathogenesis with hereditary impairment of brain maturation // Eur. J. Pediat. - 1989. - V. 149. - P. 152–158.
7. Engel J.Jr.. A proposed diagnostic scheme for people with epileptic seizures and with epilepsy: Report of the ILAE Task Force on Classification and Terminology // Epilepsia. - 2001. - V. 42. - P. 796–803.
8. Fejerman N., Caraballo R., Definition of syndromes, seizure types and nosologic spectrum. / In: Fejerman N., Caraballo R. (Eds). Benign focal epilepsies in infancy, childhood and adolescence. - France: John Libbey, 2007. - 266–15.
9. Lundberg S., Eeg-Olofsson O. Rolandic epilepsy: a challenge in terminology and classification // Eur J Paediatr Neurol. - 2003. - V. 7. - P. 239–241.
10. Panayiotopoulos C.P. Benign childhood focal seizures and related epileptic syndromes / In: C.P. Panayiotopoulos The Epilepsies: Seizures, Syndromes and Management. - 2005. - P. 223–269.
11. Patry G., Lyagoubi S., Tassinari C.A. Subclinical electrical status epilepticus induced by sleep in children // Neurol. - 1971. - V. 24. - P. 242–252.
12. Tassinari C.A., Bureau M., Dravet C., Roger J., Daniele-Natale O. Electrical status epilepticus during sleep in children (ESES) / In: Sterman M.B., Shouse M.M., Passouant P. (eds). Sleep and epilepsy. - San Diego: Academic Press, 1982. - P. 465–479.

The concept of “rhythm” in EEG refers to a certain type of electrical activity corresponding to a certain state of the brain and associated with certain cerebral mechanisms. When describing a rhythm, its frequency is indicated, typical for a certain state and region of the brain, amplitude and some characteristic features of its changes over time with changes in the functional activity of the brain.

1. Alpha(a) rhythm: frequency 8-13 Hz, amplitude up to 100 µV. It is registered in 85-95% of healthy adults. It is best expressed in the occipital regions. The a-rhythm has the greatest amplitude in a state of calm, relaxed wakefulness with eyes closed. In addition to changes associated with the functional state of the brain, in most cases spontaneous changes in the amplitude of the a-rhythm are observed, expressed in an alternating increase and decrease with the formation of characteristic “spindles” lasting 2-8 s. With an increase in the level of functional activity of the brain (intense attention, fear), the amplitude of the a-rhythm decreases. High-frequency, low-amplitude irregular activity appears on the EEG, reflecting desynchronization of neuronal activity. With a short-term, sudden external irritation (especially a flash of light), this desynchronization occurs abruptly, and if the irritation is not of an emotiogenic nature, the a-rhythm is restored quite quickly (after 0.5-2 s). This phenomenon is called “activation reaction”, “orienting reaction”, “a-rhythm extinction reaction”, “desynchronization reaction”.
2. Beta rhythm: frequency 14-40 Hz, amplitude up to 25 µV. The beta rhythm is best recorded in the area of ​​the central gyri, but also extends to the posterior central and frontal gyri. Normally, it is expressed very weakly and in most cases has an amplitude of 5-15 μV. The beta rhythm is associated with somatic sensory and motor cortical mechanisms and produces an extinction response to motor activation or tactile stimulation. Activity with a frequency of 40-70 Hz and an amplitude of 5-7 μV is sometimes called the y-rhythm; it has no clinical significance.
3. Mu rhythm: frequency 8-13 Hz, amplitude up to 50 µV. The parameters of the mu rhythm are similar to those of the normal a rhythm, but the mu rhythm differs from the latter in physiological properties and topography. Visually, the mu rhythm is observed only in 5-15% of subjects in the Rolandic region. The amplitude of the mu rhythm (in rare cases) increases with motor activation or somatosensory stimulation. In routine analysis, the mu rhythm has no clinical significance.

Types of activity that are pathological for an adult awake person

• Theta activity: frequency 4-7 Hz, amplitude of pathological theta activity >40 μV and most often exceeds the amplitude of normal brain rhythms, reaching 300 μV or more in some pathological conditions.
• Delta activity: frequency 0.5-3 Hz, amplitude same as theta activity.

Theta and delta oscillations may be present in small quantities on the EEG of an adult awake person and are normal, but their amplitude does not exceed that of the a-rhythm. An EEG containing theta and delta oscillations with an amplitude of >40 μV and occupying more than 15% of the total recording time is considered pathological.

Epileptiform activity is a phenomenon typically observed on the EEG of patients with epilepsy. They arise from highly synchronized paroxysmal depolarization shifts in large populations of neurons, accompanied by the generation of action potentials. As a result of this, high-amplitude, acute-shaped potentials arise, which have appropriate names.

• Spike (English spike - tip, peak) is a negative potential of an acute form, lasting less than 70 ms, with an amplitude >50 μV (sometimes up to hundreds or even thousands of μV).
• An acute wave differs from a spike in that it is extended in time: its duration is 70-200 ms.
• Sharp waves and spikes can combine with slow waves to form stereotypical complexes. Spike-slow wave is a complex of a spike and a slow wave. The frequency of the spike-slow wave complexes is 2.5-6 Hz, and the period, respectively, is 160-250 ms. Acute-slow wave - a complex of an acute wave and a slow wave following it, the period of the complex is 500-1300 ms.

An important characteristic of spikes and sharp waves is their sudden appearance and disappearance and a clear difference from background activity, which they exceed in amplitude. Acute phenomena with appropriate parameters that are not clearly distinguished from background activity are not designated as sharp waves or spikes.

Combinations of the described phenomena are designated by some additional terms.

• Burst is a term used to describe a group of waves with a sudden appearance and disappearance, clearly different from background activity in frequency, shape and/or amplitude.
• A discharge is a flash of epileptiform activity.
• An epileptic seizure pattern is a discharge of epileptiform activity typically coinciding with a clinical epileptic seizure. The detection of such phenomena, even if it is not possible to clearly assess the patient's state of consciousness clinically, is also characterized as an “epileptic seizure pattern.”
• Hypsarrhythmia (Greek “high-amplitude rhythm”) is a continuous generalized high-amplitude (>150 μV) slow hypersynchronous activity with sharp waves, spikes, spike-slow wave complexes, polyspike-slow wave, synchronous and asynchronous. An important diagnostic feature of West and Lennox-Gastaut syndromes.
• Periodic complexes are high-amplitude bursts of activity, characterized by a constant form for a given patient. The most important criteria for their recognition are: close to constant interval between complexes; continuous presence throughout the entire recording, subject to a constant level of functional brain activity; intra-individual stability of form (stereotyping). Most often they are represented by a group of high-amplitude slow waves, sharp waves, combined with high-amplitude, pointed delta or theta oscillations, sometimes reminiscent of epileptiform acute-slow wave complexes. The intervals between complexes range from 0.5-2 to tens of seconds. Generalized bilateral synchronous periodic complexes are always combined with profound disturbances of consciousness and indicate severe brain damage. If they are not caused by pharmacological or toxic factors (alcohol withdrawal, overdose or sudden withdrawal of psychotropic and hypnosedative drugs, hepatopathy, carbon monoxide poisoning), then, as a rule, they are a consequence of severe metabolic, hypoxic, prion or viral encephalopathy. If intoxication or metabolic disorders are excluded, then periodic complexes with high certainty indicate a diagnosis of panencephalitis or prion disease.

Variants of the normal electroencephalogram of an adult awake person

The EEG is essentially uniform across the entire brain and symmetrical. The functional and morphological heterogeneity of the cortex determines the characteristics of the electrical activity of various areas of the brain. The spatial change in EEG types of individual brain regions occurs gradually.

In the majority (85-90%) of healthy adults, with their eyes closed at rest, the EEG shows a dominant a-rhythm with maximum amplitude in the occipital regions.

In 10-15% of healthy subjects, the amplitude of oscillations on the EEG does not exceed 25 μV; high-frequency low-amplitude activity is recorded in all leads. Such EEGs are called low-amplitude. Low-amplitude EEGs indicate the predominance of desynchronizing influences in the brain and are a normal variant.

In some healthy subjects, instead of the alpha rhythm, activity of 14-18 Hz with an amplitude of about 50 μV is recorded in the occipital regions, and, like the normal alpha rhythm, the amplitude decreases in the anterior direction. This activity is called the “fast a-variant.”

Very rarely (0.2% of cases), regular, close to sinusoidal, slow waves with a frequency of 2.5-6 Hz and an amplitude of 50-80 μV are recorded on the EEG with eyes closed in the occipital regions. This rhythm has all the other topographic and physiological characteristics of the alpha rhythm and is called the “slow alpha variant.” Not being associated with any organic pathology, it is considered as borderline between normal and pathological and may indicate dysfunction of diencephalic nonspecific brain systems.

Electroencephalogram changes in the sleep-wake cycle

• Active wakefulness (during mental stress, visual tracking, learning and other situations requiring increased mental activity) is characterized by desynchronization of neuronal activity; low-amplitude, high-frequency activity predominates on the EEG.
• Relaxed wakefulness is the state of the subject resting in a comfortable chair or on a bed with relaxed muscles and closed eyes, not engaged in any special physical or mental activity. Most healthy adults in this condition show a regular alpha rhythm on the EEG.
• The first stage of sleep is equivalent to dozing. The EEG shows the disappearance of the alpha rhythm and the appearance of single and group low-amplitude delta and theta oscillations and low-amplitude high-frequency activity. External stimuli cause bursts of alpha rhythm. Duration of the stage is 1-7 minutes. Towards the end of this stage, slow oscillations with an amplitude appear
• The second stage of sleep is characterized by the appearance of sleep spindles and K-complexes. Sleepy spindles are bursts of activity with a frequency of 11-15 Hz, predominant in the central leads. The duration of the spindles is 0.5-3 s, the amplitude is approximately 50 μV. They are connected With median subcortical mechanisms. The K-complex is a burst of activity typically consisting of a biphasic high-amplitude wave with an initial negative phase, sometimes followed by a spindle. Its amplitude is maximum in the area of ​​the crown, duration is not less than 0.5 s. K-complexes occur spontaneously or in response to sensory stimuli. At this stage, bursts of polyphasic high-amplitude slow waves are also occasionally observed. There are no slow eye movements.
• The third stage of sleep: spindles gradually disappear and delta and theta waves with an amplitude of more than 75 μV appear in an amount from 20 to 50% of the time of the analysis epoch. At this stage it is often difficult to differentiate K-complexes from delta waves. Sleep spindles may disappear completely.
• The fourth stage of sleep is characterized by waves with a frequency
• During sleep, a person occasionally experiences periods of desynchronization on the EEG - so-called rapid eye movement sleep. During these periods, polymorphic activity with a predominance of high frequencies is recorded. These periods on the EEG correspond to the experience of a dream, a drop in muscle tone with the appearance of rapid movements of the eyeballs and sometimes rapid movements of the limbs. The occurrence of this stage of sleep is associated with the work of the regulatory mechanism at the level of the pons; its disturbances indicate dysfunction of these parts of the brain, which is of important diagnostic significance.

Age-related changes in the electroencephalogram

The EEG of a premature baby up to 24-27 weeks of gestation is represented by bursts of slow delta and theta activity, occasionally combined with sharp waves, lasting 2-20 s, against a background of low-amplitude (up to 20-25 μV) activity.

In children 28-32 weeks of gestation, delta and theta activity with an amplitude of up to 100-150 μV becomes more regular, although it may also include bursts of higher amplitude theta activity, interspersed with periods of flattening.

In children older than 32 weeks of gestation, functional states begin to be visible on the EEG. In quiet sleep, intermittent high-amplitude (up to 200 μV and above) delta activity is observed, combined with theta oscillations and sharp waves and interspersed with periods of relatively low-amplitude activity.

In a full-term newborn, the EEG clearly distinguishes between wakefulness with eyes open (irregular activity at a frequency of 4-5 Hz and an amplitude of 50 μV), active sleep (continuous low-amplitude activity at 4-7 Hz with superimposition of faster low-amplitude oscillations) and quiet sleep characterized by bursts high amplitude delta activity in combination with spindles of faster high amplitude waves interspersed with low amplitude periods.

In healthy premature infants and full-term newborns, alternating activity during quiet sleep is observed during the first month of life. The EEG of newborns contains physiological acute potentials, characterized by multifocality, sporadic occurrence, and irregular pattern. Their amplitude usually does not exceed 100-110 µV, the frequency of occurrence is on average 5 per hour, the main number of them is confined to restful sleep. Relatively regularly occurring sharp potentials in the frontal leads, not exceeding 150 μV in amplitude, are also considered normal. A normal EEG of a mature newborn is characterized by the presence of a response in the form of EEG flattening to external stimuli.

During the first month of life of a mature child, the alternating EEG of quiet sleep disappears; in the second month, sleep spindles appear, organized dominant activity in the occipital leads, reaching a frequency of 4-7 Hz at the age of 3 months.

During the 4-6th month of life, the number of theta waves on the EEG gradually increases, and delta waves decrease, so that by the end of the 6th month the rhythm with a frequency of 5-7 Hz dominates on the EEG. From the 7th to the 12th month of life, the alpha rhythm is formed with a gradual decrease in the number of theta and delta waves. By 12 months, oscillations dominate, which can be characterized as a slow alpha rhythm (7-8.5 Hz). From 1 year to 7-8 years, the process of gradual displacement of slow rhythms by faster oscillations (alpha and beta range) continues. After 8 years, the alpha rhythm dominates on the EEG. The final formation of the EEG occurs by 16-18 years.

Limit values ​​of the frequency of the dominant rhythm in children

The EEG of healthy children may contain excessive diffuse slow waves, bursts of rhythmic slow oscillations, discharges of epileptiform activity, so that from the point of view of traditional assessment of the age norm, even in obviously healthy individuals under the age of 21 years, only 70-80 can be classified as “normal”. % EEG.

From 3-4 to 12 years of age, the proportion of EEG with excess slow waves increases (from 3 to 16%), and then this figure decreases quite quickly.

The reaction to hyperventilation in the form of the appearance of high-amplitude slow waves at the age of 9-11 years is more pronounced than in the younger group. It is possible, however, that this is due to less clear performance of the test by younger children.

Representation of some EEG variants in a healthy population depending on age

The already mentioned relative stability of the EEG characteristics of an adult remains until approximately 50 years of age. From this period, a restructuring of the EEG spectrum is observed, expressed in a decrease in the amplitude and relative amount of the alpha rhythm and an increase in the number of beta and delta waves. The dominant frequency after 60-70 years tends to decrease. At this age, in practically healthy individuals, theta and delta waves also appear visible during visual analysis.

Electroencephalographic monitoring (EGG monitoring) is today the main research method, the purpose of which is to register a paroxysmal event in order to make a differential diagnosis between epileptic and non-epileptic conditions, for example, parasomnias, syncope, stereotypies and others.

Widespread use of the EEG monitoring method in the first half of the 90s. made literally revolutionary changes in the diagnosis of epilepsy and made it possible to recognize clinically complex seizures. It became clear that many types of seizures do not fit into the classical picture described in medical textbooks, which led to a revision of views on the diagnosis and treatment of patients.

An EEG is prescribed to obtain answers to the following questions:

• What is the nature of seizures - epileptic or non-epileptic? (what disease to treat)
• What form of epilepsy? (how to treat correctly, what medications)
• What is the location of the attack? (raising the question of the advisability of surgical treatment if medication is ineffective)
• How does the treatment proceed? (change, cancel medications)

Before we begin to answer these questions, it is necessary to understand the origin of this method, and then come to the fruits, the results of many years of research, which have grown in abundance on this powerful trunk.

2. Concepts defining VEEG

The main concepts that can be identified when analyzing the concept of video-EEG monitoring are EEG and epilepsy.

Let's remember the definition of epilepsy: epilepsy is one of the common chronic diseases of the brain. By definition, epilepsy is a chronic disease of the brain characterized by repeated unprovoked attacks of impairment of motor, sensory, autonomic, mental or mental functions resulting from excessive neural discharges (ILAE, 1989).

Electroencephalography is a method for studying the bioelectrical activity of the brain, based on determining the difference in electrical potentials generated by neurons during their life. The recording electrodes are positioned so that all major parts of the brain are represented in the recording. The resulting recording - EEG - is the total electrical activity of millions of neurons, represented primarily by the potentials of dendrites and nerve cell bodies: excitatory and inhibitory postsynaptic potentials and partially by the potentials of dendrites and nerve cell bodies. That is, EEG is a kind of visualized result of the functional activity of the brain.

Here it would probably be worth paying some attention to the anatomy of the neuron and its physiology.

A neuron is the main cell of the central nervous system. The shapes of neurons are extremely diverse, but the main parts are unchanged in all types of neurons: the body and numerous branched processes. Each neuron has two types of processes: an axon, along which excitation is transmitted from a neuron to another neuron, and numerous dendrites (from the Greek tree), on which axons from other neurons end in synapses (from the Greek contact). The neuron conducts excitation only from the dendrite to the axon.

The main property of a neuron is the ability to excite (generate an electrical impulse) and transmit (conduct) this excitation to other neurons, muscle, glandular and other cells.

Neurons in different parts of the brain perform very diverse jobs, and accordingly, the shape of neurons from different parts of the brain is also diverse.

Many years of research in the field of neurophysiology have led to the conclusion that the following electrical events are inherent in neurons and can contribute to the total bioelectrical activity of the brain (EEG): postsynaptic excitatory and inhibitory potentials (EPSP, IPSP), and propagating action potentials (AP). EPSPs and IPSPs arise either in the dendrites or on the soma of the neuron. APs are generated in the axon hillock area and then spread along the axon.

Neuron. Excitatory and inhibitory PSPs, action potential.

Conventional spontaneous EEG, its basic rhythms arise as a result of the spatial and temporal summation of postsynaptic potentials (PSP) of a large number of cortical neurons. The time characteristics of the summation process are quite slow compared to the duration of the AP.

A certain degree of synchronization is set by various subcortical structures that act as a “pacemaker” or pacemaker. Among them, the thalamus plays the most significant role in the generation of EEG rhythms.

Action potentials of cortical neurons do not play a significant role in the generation of basic EEG rhythms because they are very short. The decisive role of PD in the formation of EEG patterns occurs in situations where a significant number of neurons are synchronized and simultaneously produce bursts or “bursts” of PD. This mode is typical for paroxysmal events, for example, for epileptic seizures, and then the morphology of EEG waves is largely determined by action potentials. In this case, the sharp components of the EEG (spikes, sharp waves) do not reflect individual action potentials, but rather the entire “packet” of action potentials. This is how many epileptiform EEG patterns are formed, the best known of which is the spike-wave complex. It should be noted that a similar model is also applicable in explaining the genesis of physiological acute EEG components.

Thus, both postsynaptic potentials and action potentials take part in the generation of EEG. The basic rhythm of the EEG is determined by gradual changes in postsynaptic potentials due to the spatial and temporal summation of individual PSPs in large populations of neurons that are relatively synchronized and under the influence of the subcortical pacemaker. Paroxysmal events, synchronizing a significant number of neurons that produce bursts of action potentials, are responsible for the formation of many epileptiform EEG phenomena, in particular spike-wave complexes.

Electroencephalography actually studies this entire process.

2.2. History of EEG studies

The study of electrical processes in the brain began with D. Reymond in 1849, who showed that the brain, like nerves and muscles, has electrogenic properties.

Electroencephalographic research was started by V.V. Pravdich-Neminsky, who published the first electroencephalogram recorded from the brain of a dog in 1913. In his research he used a string galvanometer. Pravdich-Neminsky also introduces the term electrocerebrogram.

The first human EEG recording was obtained by the Austrian psychiatrist Hans Berger in 1928. He also proposed to call the recording of brain biocurrents "electroencephalogram».

As computer technology improved, in 1996, a method of outpatient polygraphic recording was implemented using a 17-channel electroencephalograph (16 EEG channels and 1 ECG channel) using a portable personal computer (laptop).

And finally, by the end of the 20th century, several types of EEG techniques were available in the arsenal of epilethological and neurophysiological services: routine EEG, Holter EEG and VEEG.

EEG has become a “razor blade”, the most high-quality and informative method for diagnosing a form of epilepsy and allows you to register the clinical-electroencephalographic correlate of an epileptic attack, which makes it possible to establish a more accurate diagnosis and prescribe a rational regimen of anti-epileptic therapy.

3. Conducting an EEG. View from 3 positions

EEG monitoring can be considered from 3 positions: the patient, the doctor who is conducting the study at the moment, and from the doctor who deciphers the video-EEG monitoring after the fact.

As a preface, it’s worth simply mentioning the indications and contraindications for this study (Avakyan)

Indications:

• Diagnosis of epilepsy and epileptic syndromes.
• Paroxysmal conditions of unknown origin, raising suspicion of epilepsy.
• Pharmacoresistant seizures (in order to identify pseudoepileptic paroxysms or clarify the form of epilepsy).
• Monitoring the effectiveness of treatment.
• Drug remission (objective statement of remission).
• Preparation for discontinuation of anticonvulsant therapy.
• Presurgical examination.
• Subclinical epileptic activity.
• Progressive cognitive and behavioral disorders in children.
• First seizure.

Contraindications:
There are no contraindications to performing an EEG.

3.1. VEEG laboratory design

The essence of the VEEG method is the continuous recording of the EEG signal and video image of the patient for a long time. The minimum duration of the study is 15 minutes, the maximum is not limited (up to 7-14 days). A prerequisite is perfect synchronization of the video image and EEG in time.

The basis of the EEG monitoring system is a multichannel signal amplifier, which has the ability to record 19-32-64-128-channel EEG, ECG channel, respiration sensor, electromyographic and electrooculographic channels.

The corresponding recording sensors are connected to the amplifier. EEG electrodes are attached for long-term recording using a special cap or adhesive paste. The design of the electrode system allows the patient to move around the room, does not cause inconvenience and makes the examination comfortable.

Signals from the amplifier are sent via wired or wireless communication to a computer workstation.

The video image is recorded using digital video cameras; their number can be arbitrary; most systems provide the possibility of using 1-2 cameras.

The results are processed by studying a synchronous EEG image and a video image; the image scrolling speed is chosen arbitrarily. The EEG processing program includes spectral and coherence analysis capabilities, three-dimensional dipole localization programs, and other computer analysis options.

The video-EEG monitoring department should include 3 main units:

1. patient room equipped with video cameras, microphone, patient button for recording events;
2. room for recording stations and personnel monitoring and monitoring the patient.
3. a room for doctors (residency), where stations for viewing and analyzing recorded data are located. An important requirement for VEEG equipment is the ability to view and process previously recorded studies or current ones without interrupting the current study.

3.2. Installation diagrams, patient preparation and start of the study

The doctor conducting the study places electrodes either built into the cap or sticks each electrode in turn according to its place. In normal practice, EEG recording electrodes are placed according to the international “10 -20” system.

In accordance with the “10 -20” system, three measurements of the subject’s skull are taken:

1. longitudinal size of the skull - measure the distance along the skull between the transition point of the frontal bone into the bridge of the nose (nasion) and the occipital protuberance;
2. transverse size of the skull - measure the distance along the skull through the crown (vertex) between the external auditory canals of both ears;
3. the length of the head circumference, measured at the same points.

Electrodes located along the midline are marked with a Z index; the leads on the left side of the head have odd indices, and those on the right have even indices.

Leads in the “10 -20” system:

• frontal (F1, F2., F3 F4, Fz);
• frontal poles (Fp1, Fp2);
• central (C1, C2, C3, C4, Cz);
• parietal (P1, P2 P3 P4, Pz);
• temporal (T1, T2, T3, T4, T5, Tz);
• occipital (O1, O2, 0z).

Fastening and application of electrodes is carried out in the following order:

1. The electrodes are connected to the amplifier. To do this, the electrode plugs are inserted into the electrode sockets of the amplifier.
2. Use a cotton swab dipped in alcohol to degrease the areas intended for placing electrodes.
3. Immediately before placing each electrode, electrode gel is applied to the surface in contact with the skin. It must be remembered that the gel used as a conductor must be intended for electrodiagnostics.
4. The patient is put on a helmet/hat with built-in surface electrodes or each surface electrode separately and secured with a special glue - collodion. The practice of needle electrodes is now being abandoned according to recent research by scientists in the USA and Great Britain. The locations of the electrodes are determined according to the electrode arrangement system. It must be remembered that the applied electrodes should not cause discomfort in the patient.
5. In accordance with the designations indicated on the amplifier panel, the electrodes are installed in the places provided by the system, paired electrodes are located symmetrically.

After proper installation and calibration, the VEEG study itself begins. In today's practice, VEEG studies are used 4-5 hours long (morning/day/evening), 9-10 hours long (night), 24 hours long or more (Holter VEEG monitoring). The most common today are short VEEG studies (60%), followed by night studies - 36%, Holter studies - 4-5%

Premedication before the study, as a rule, is not carried out, since the administration of drugs not included in the treatment regimen can change the EEG picture, which will not allow assessing the true parameters of the bioelectric activity of the brain.

Sleep EEG is of fundamental importance in the diagnosis of epilepsy. According to leading experts, "registration of an EEG during one minute of light sleep provides more information for diagnosing epilepsy than an hour of study while awake."

4. Concepts of norm and pathology in VEEG

4.1. VEEG standards

Alpha rhythm. The rhythm with a frequency of 8-13 Hz with an average amplitude of 50 μV (15-100 μV), is maximally expressed in the posterior (occipital) leads with eyes closed. The appearance of modulations of the alpha rhythm (“spindles”) is possible, consisting of a periodic increase and decrease in the amplitude of the waves. The severity of the alpha rhythm depends on many conditions, which must be taken into account when analyzing the EEG. The presence of the alpha rhythm on the EEG and its regularity decrease when opening the eyes, recording in a state of anxiety, during active mental activity (problem solving), and also during sleep. In women during menstruation, its frequency may increase. It has been established that in a healthy adult, the frequency of the alpha rhythm is quite stable and is genetically determined.

Mu (rolandic, arched) rhythm. The rhythm is arched, alpha frequency (usually 8-10 Hz). The amplitude does not exceed the alpha rhythm (usually somewhat lower); is registered in the central regions of 20% of healthy adults. In children, this rhythm begins to be well defined from the age of 3 months, better in girls. It does not respond to opening the eyes, but is blocked on one side when performing movements in the contralateral limb. It has little diagnostic value, even with its significant enhancement or pronounced asymmetry.

Beta rhythm. Rhythm with a frequency of more than 13 Hz, an average amplitude of 10 μV; maximally expressed in the anterior sections. The typical beta rhythm frequency is normally 18-25 Hz, a less common rhythm frequency is 14-17 Hz and extremely rarely - over 30 Hz. In 70% of healthy people, the amplitude of the beta rhythm does not exceed 10 μV; and only 3% exceed 20 µV. The beta rhythm is most pronounced in the fronto-central leads. Beta activity increases somewhat during the period of drowsiness, when falling asleep (stage I sleep), during FBS and sometimes upon awakening. During the period of deep sleep (stages III, IV of the slow-wave sleep phase), its amplitude and severity decrease significantly.

A persistent increase in the amplitude of beta activity above 25 μV, especially with its spread to the posterior leads, is a sign of pathology, however, it is not nosologically specific. Traditionally, increased beta activity (“excessive fast”) has been associated with the ongoing epileptic process.

Theta rhythm. A rhythm with a frequency of 4-7 Hz, in amplitude, usually exceeding the main activity of the background recording. Occurs in varying degrees of severity on the EEG in all healthy children. Theta activity begins to be recorded in the central regions already from 3 weeks of age, gradually increasing with age and reaching a maximum at 4-6 years. At this age, the theta rhythm is dominant on the EEG in children. Most researchers believe that in adolescents and young adults, when awake with their eyes closed, low-amplitude theta activity (not exceeding background amplitude) at a frequency of 6-7 Hz with a bifrontal predominance is normal if it does not exceed 35% of the background recording.

4.2. Recording in a dream

Sleep is a powerful activator of epileptiform activity. It is important for a neurologist, and even more so an epileptologist, to be able to identify the phases and stages of sleep. It is known that epileptiform activity is observed mainly in stages I and II of slow-wave sleep, while during “delta sleep” and during the FBS period it is most often suppressed.

Currently, the classification of Dement & Kleitman as modified by Recbtshaffen & Kales (1968) is used to differentiate the stages of sleep. According to this classification, 2 phases of sleep are distinguished: the slow-wave sleep phase (FMS) and the rapid eye movement sleep phase (REM),

FMS (in English literature - non-REM sleep) develops against the background of a weakening influence of the activating cortex, ascending reticular formation and increased activity of synchronizing inhibitory structures.

In FMS there are 4 stages.

Stage I sleep (drowsiness) characterized by a moderate slowing of the main activity on the EEG. It is manifested by the gradual disappearance of the alpha rhythm and the appearance of rhythmic theta activity in the central and fronto-central region. Periodic rhythmic high-amplitude slow activity with a frequency of 4-6 Hz may appear in the frontal leads. The duration of stage I sleep in a healthy person is no more than 10-15 minutes.

Stage II of sleep (sleep spindle stage). The following phenomena are observed. 1. A characteristic sign of stage II sleep is the appearance of “sleep spindles” or sigma rhythm. This phenomenon is a rhythmic spindle-like burst of increasing and decreasing amplitude with a frequency of 12-16 Hz and an amplitude of 20-40 μV, mainly in the central parietal regions. The duration of “sleep spindles” ranges from 0 to 2 seconds. High-amplitude and long-lasting (about 3 seconds) sleep spindles with a predominance in the frontal leads are usually a sign of pathology.

Stage III sleep characterized by an increase in the amplitude and number of slow waves, mainly in the delta range. K-complexes and sleep spindles are recorded. Delta waves occupy up to 50% of the recording during the EEG analysis period. There is a decrease in the beta activity index.

Stage IV sleep characterized by the disappearance of “sleep spindles” and K-complexes, the appearance of high-amplitude (at least 50 μV) delta waves, which at the time of EEG analysis account for more than 50% of the recording. Stages III and IV of sleep are the deepest sleep. They are united under the general name “delta sleep”.

In the REM sleep phase (paradoxical sleep, REM sleep), there is a weakening of the influence of the inhibitory reticular formation and an increase in desynchronizing activating mechanisms. When entering the FBS, beta activity increases. This phase of sleep is characterized by the appearance on the EEG of a desynchronization pattern in the form of irregular activity with single low-amplitude theta waves, rare groups of slow alpha rhythm and sharp “sawtooth” waves. FBS is accompanied by rapid movements of the eyeballs and a diffuse decrease in muscle tone. It is during this phase of sleep that healthy people dream. The onset of sleep from the REM phase or its occurrence less than 15 minutes after falling asleep is a sign of pathology.

Normal sleep for adults and children consists of alternating a series of cycles of FMS and FBS. FMS is most pronounced in the first half of the night and occupies 75% of all sleep. In the second half of the night, the FBS (dream phase) is most represented, which occupies about 25% of night sleep. The duration of one sleep cycle in young children is 45-55 minutes; for adults 75-100 minutes. During the night, a healthy person experiences from 4 to 6 sleep cycles.

4.3. Slow wave activity.

Slow wave activity. This term includes activity on the EEG in the form of a slower rhythm compared to age-related norms. According to the international classification, the following variants of slow wave activity are distinguished:

1. slowdown of basic activity;
2. periodic slowdown;
3. continued deceleration.

Slowdown of the main activity is stated when the main rhythms have slower frequency characteristics compared to the age norm: at 1 year - frequency less than 5 Hz, at 4 years - less than 6 Hz, at 5 years - less than 7 Hz, at 8 years and older - less than 8 Hz

Intermittent slowdown. Periodic slowing can be irregular and rhythmic, generalized and regional. Severe periodic rhythmic generalized slowing (usually with a predominance in the frontal leads) is sometimes observed in generalized forms of epilepsy. Irregular regional slowing (usually in the temporal leads) may be an indirect EEG sign of partial epilepsy or local organic brain damage.

Continued deceleration is noted if this pattern occupies about 90% of the recording, and there is no reaction to external stimuli. It is always a pathological sign and indicates a progressive focal destructive lesion of the brain. In this case, slow-wave activity reflects a change in cortical electrogenesis caused by an anatomical defect in the nonironal networks. It can be combined with a normal or slow basic rhythm; occurs along one of the leads (for example, the left temporal) or throughout the entire hemisphere. As a rule, it is represented by theta (less often delta) activity of low amplitude, which does not respond to exogenous stimuli.

4.4. Provoking tests

Provoking tests. Background recording of bioelectrical activity of the brain is carried out in a state of passive wakefulness of the patient with his eyes closed. In order to identify EEG disorders, provoking tests are used. The most significant of them are the following:

1. Opening and closing eyes.
2. Hyperventilation.
3. Rhythmic photostimulation.
4. Phonostimulation.
5. Sleep deprivation.
6. Stimulation of mental activity.
7. Stimulation of manual activity.

Let's look at the first ones in detail.

Eye opening-closing test serves to establish contact with the patient. At the same time, the medical worker makes sure that the patient is conscious and follows instructions. This test allows us to identify the reactivity of the alpha rhythm and other types of activity to opening the eyes. Normally, when the eye opens, the alpha rhythm, normal and conditionally normal slow-wave activity is blocked. On the contrary, a lack of pattern response to eye opening is usually a sign of pathological activity. Blocking of occipital peak-wave activity during eye opening in patients with benign occipital Gastaut epilepsy is an important differential feature from symptomatic occipital epilepsy. It should be remembered that in some forms of photosensitivity epilepsy, epileptiform activity on the EEG occurs at the moment of closing the eyes. This may be due to the disappearance of gaze fixation when the eyes are closed. This phenomenon was described by Panayiotopoulos (1998) and was called “fixation off” or photosensitivity.

Hyperventilation actually carried out in children after 3 years. Duration from 3 minutes for children to 5 minutes for adults. Hyperventilation should not be performed at the very end of the EEG recording, since pathological activity often appears some time after the end of the test. The main purpose of hyperventilation is to detect generalized spike-wave activity, and sometimes to visualize the attack itself (usually absence seizure). Regional epileptiform activity appears less frequently. According to the observations of Blago-sklonova N.K. and Novikova L.A. (1994), the appearance of paroxysmal bursts of slow waves during hyperventilation is characteristic of healthy children and adolescents and is a variant of the norm. According to Daly & Pediey (1997), the pathological response to hyperventilation involves only the appearance of peak-wave activity or marked asymmetry in patterns on the EEG. It is fundamentally important that any other reaction, including the appearance of delta activity, is an individual version of the norm. Thus, according to modern views, the assessment of paroxysmal generalized (often with bifrontal predominance) rhythmic theta-delta activity during hyperventilation as a hypothetical “dysfunction of meso-diencephalic structures” is untenable. Such an assessment of essentially normal patterns has no clinical significance and leads to terminological confusion and unnecessary worry for both neurologists and patients themselves.

Rhythmic photostimulation(RFS) is the most important test for identifying pathological activity in photosensitivity forms of epilepsy. The classic technique of Jeavons & Harding (1975) is used. The strobe lamp should be located 30 cm from the patient's closed eyes. It is necessary to use a wide range of frequencies, starting from 1 flash per second and ending with a frequency of 50 Hz. The most effective in detecting epileptiform activity is standard XRF with a frequency of 16 Hz. The following reactions to RFS are possible:

• No obvious reaction.
• Rhythm acquisition: the appearance of oscillations in the EEG is synchronous with flashes during RFS.
• Photomyoclonic response: With RFS, there is a “fluttering” of the eyelids and twitching of the psriocular muscles (myoclonic hyperkinesis) synchronously with flashes of light. This is reflected on the EEG as a distinct “rhythmic myographic artifact” in the anterior leads.
• Photoparoxysmal response: the appearance of epileptiform activity during RFS; short discharges of generalized fast (4 Hz and higher) polypeak-wave activity occur more often. According to the classification of photosensitive epilepsy (Binnie et al., 1992), a form of photosensitive epilepsy is distinguished, in which seizures occur exclusively in laboratory conditions during XRF during an EEG study. The most typical occurrence of myoclonic paroxysms involving the muscles of the face, shoulder girdle and arms, synchronously with flashes of light. In everyday life there are no attacks, even when exposed to household factors RFS (flickering light). As a rule, this form of epilepsy is detected accidentally when patients are referred for an EEG study for reasons unrelated to epilepsy. Most authors do not recommend the use of AEDs for this form, and the very classification of such cases as epilepsy is questionable. The photoparoxysmal response highly reliably correlates with the presence of photosensitive epilepsy.

4.5. Artifacts

Artifacts are any graph elements on the EEG that are not a reflection of the electrical activity of the brain. They are divided into mechanical and bioelectric. Mechanical artifacts can be instrumental, electrode or electrical. The most common artifact is due to “interference” from the alternating current network (lack of grounding, use of various medical equipment nearby) in the form of sinusoidal oscillations of a frequency of 50 Hz.

Bioelectric artifacts are classified as follows:

1. Myogenic artifacts. The most common type of artifact. High-frequency oscillations of the myogram are recorded, usually predominant in the temporal leads. They are most often caused by tension in the chewing muscles, facial muscles, and neck muscles. The artifact from fasciculatory tremor resembles an arched mu rhythm and is observed maximally in the frontotemporal leads. Glossokinetic artifact occurs during rhythmic movements of the tongue, for example during speaking or sucking (feeding infants during an EEG study).
2. Cardiac and respiratory artifacts. An electrode located on a large vessel can cause an artifact resembling a graph element of a rheoencephalogram. Electrocardiographic potentials may be recorded on the EEG, which must be distinguished from benign epileptiform disorders of childhood. These potentials predominate on the electroencephalogram during electrocerebral inactivation (brain death). Artifacts caused by chest excursion (often during hyperventilation) are also encountered.
3. Oculographic artifacts. Associated with the activity of m. orbicularis oculi and are usually recorded in the frontal leads. Occurs with rhythmic blinking (thyroid hyperkinesis), nystagmus.
4. Artifacts caused by changes in skin resistance. Changes in skin resistance can be caused by various biochemical processes in the body. Most often, this type of artifact occurs when patients become agitated during an EEG study, which is accompanied by severe sweating.

At the same time, the doctor performing monitoring must be able to differentiate these artifacts. If, for example, the artifact does not go away over time, it is necessary to check the electrode for proper connection with the amplifier and the patient and, if necessary, replace/adjust it.

5. Epileptiform activity

Epileptiform activity is characterized by the appearance of sharp waves or peaks on the EEG, which differ sharply from the main background activity and occur predominantly in individuals suffering from epilepsy. The classification of EEG disorders adopted by the American Neurophysiological Association adheres to strict terminology in designating pathological phenomena. In classification the term is generally accepted "epileptiform activity", due to its exclusive application to electroencephalographic phenomena.

According to the classification of EEG disorders, there are 9 interictal (interictal) and two seizure (ictal) epileptiform patterns.

Interictal epileptiform changes:

• peaks ( spikes);
• sharp waves;
• benign epileptiform disorders of childhood (BEND, “Rolandic” complexes);
• peak-slow wave complexes;
• peak-slow wave complexes 3 Hz;
• slow peak-slow wave complexes;
• multiple peaks (polyspikes);
• hypsarrhythmia;
• photoparoxysmal response (photoparoxysmal reaction).

Ictal epileptiform changes:

• EEG of the attack;
• EEG status.

Let's consider all the indicated variants of epileptiform disorders on the EEG:

1. Peaks ( spikes)- an epileptiform phenomenon that is different from the main activity and has a peak shape. The peak period ranges from 40 to 80 ms. This is a specific epileptiform pattern that is observed within various forms of epilepsy (generalized and partial). Single peaks are extremely rare; they usually precede the appearance of waves. According to the basic principles of electrophysiology, the appearance of spikes on the EEG reflects the processes of excitation of cortical neurons, and slow waves reflect the processes of inhibition.

2. Sharp wave- an epileptiform phenomenon, different from the main activity, the period of which is 80-200 ms. According to a number of authors, this pattern is rarely observed in healthy people, and is highly specific for epilepsy. Sharp waves, as well as peaks, can be recorded in the form of regional, multiregional and generalized phenomena. An acute wave can occur either in isolation (especially in partial forms of epilepsy) or preceding a slow wave. It should be remembered that sharp waves, like peaks, can represent normal physiological phenomena: benign epileptiform sleep transits (BETS), Wicket potentials, 14 and 6 Hz positive spikes and some others.

3. Benign epileptiform disorders of childhood (BED) is an epileptiform phenomenon that is represented as a stereotypical electric dipole consisting of a sharp wave followed by a slow wave. The amplitude of the negative pole is 150-300 μV, often 2 times greater than the positive one. The total period of the complex is 80-120 ms. This pattern is easily recognizable due to its typical morphology, reminiscent of QRST waves on an ECG [Mukhin K. Yu. et al., 2001]. DEND complexes are characterized by a tendency towards their grouping (doublets, triplets, etc.), as well as an increase in their representation and amplitude during the slow-wave sleep phase. Benign epileptiform disorders of childhood occur mainly between the ages of 3 and 14 years and are a characteristic pattern in idiopathic partial forms of epilepsy. With the onset of puberty, their severity decreases, and in most cases they gradually disappear after 14-15 years. It is assumed that this EEG pattern is age-dependent and genetically determined with autosomal dominant inheritance with low penetrance and variable expressivity.

4. Peak-slow wave complexes— represent a pattern consisting of a peak followed by a slow wave. Most often, peak-slow wave complexes are recorded in the form of generalized discharges, the representation and amplitude of which are enhanced in the FMS, during GV and RFS. This EEG pattern is highly specific for idiopathic generalized forms of epilepsy in childhood and adolescence. However, according to Doose & Baier (1987), in 10-17% of cases, generalized peak-slow wave complexes can be found in clinically healthy individuals, mainly in relatives of probands with absence forms of epilepsy.

In the form of single patterns, peak-slow (or acute-slow) wave complexes are found in cryptogenic and symptomatic forms of partial epilepsy.

5. Peak-slow wave complexes with a frequency of 3 Hz- represent a regular discharge of generalized patterns consisting of single spikes followed by a slow wave with a frequency of 2.5 to 3.5 Hz. According to the classification of EEG disorders, to classify patterns into this group, the duration of these complexes must be more than 3 seconds. The frequency of complexes during a discharge is not constant. At the beginning of the discharge it is 3-4 Hz, while towards the end it decreases to 2.5-2.25 Hz. Characteristic is the amplitude predominance of patterns in the frontal leads. NREM sleep causes activation of peak-wave complexes. In this case, the duration of discharges during sleep is shortened and at the same time a slight slowdown in the frequency of complexes is possible. This EEG pattern is characteristic of absence forms of epilepsy, especially childhood absence epilepsy. A discharge duration of peak-wave complexes of more than 3 seconds is highly likely to be an ictal phenomenon of typical absence seizures.

6. Slow peak-slow wave complexes- represent irregular discharges of peak (and more often - sharp wave)-slow wave complexes, with a frequency of less than 2.5 Hz. According to the classification of EEG disorders, the duration of these complexes should be more than 3 seconds. The complexes consist of bi- and triphasic negative sharp waves with a period of 150-200 ms. and the following high-amplitude (300 -400 μV) negative slow waves. They are bilaterally synchronous, however, in some cases their amplitude asymmetry and initial asynchrony are possible. A characteristic feature of this pattern is the tendency to increase the severity of changes during FMS.

7. Polypeaks (multiple peaks)- are defined as a group of generalized bilaterally synchronous, successive 3 or more frequency peaks from 10 Hz and above. Each group of polyps can end with a slow wave (polypeak-wave complexes). Generalized polyps are a specific pattern for myoclonic forms of epilepsy, such as juvenile myoclonic epilepsy, benign myoclonic epilepsy of infancy. However, this pattern can also occur in partial forms of epilepsy, in patients with Lennox-Gastaut syndrome, as well as in cases of progressive epilepsy with myoclonus (Lafora disease, Unferricht-Lundborg disease, etc.).

8. Hypsarrhythmia- an epileptiform pattern characterized by irregular diffuse continuous high-amplitude (>300 μV) slow-wave activity (1-3 Hz), against the background of which multiregional peaks and sharp waves are recorded. In some cases, a transient short-term flattening of this activity is possible (up to bioelectrical silence). This variant of hypsarrhythmia was called the burst-suppression pattern by Ohtahara (1978). In some cases (symptomatic variant of West syndrome), hypsarrhythmia significantly dominates in one of the hemispheres, combined with persistent regional adhesions in this zone. Sleep significantly modifies hypsarrhythmia: during FMS, the amplitude and presentation of epileptiform changes increases and becomes periodic, while in REM sleep it decreases or disappears completely.

9. Photoparoxysmal response. Characterized by the appearance of epileptiform activity, both generalized and regional (mostly, in the occipital regions of the cerebral cortex), which appears upon presentation of rhythmic photostimulation of various frequencies. The maximum response is observed at an RFS frequency of about 16 Hz with eyes closed. It is better revealed during reference editing. The photoparoxysmal response can continue after the end of light stimulation, which is typical for photosensitivity forms of epilepsy: primary photosensitivity epilepsy, idiopathic photosensitivity occipital epilepsy, Unferricht-Lundborg disease and some others.

10. Ictal EEG patterns. EEG seizure - a sudden change in bioelectrical activity, regional or diffuse, associated with an epileptic seizure. In many cases, for the differential diagnosis of ictal and interictal epileptiform disorders on the EEG, the only method is video-EEG monitoring. However, the short duration of the occurrence of some patterns (for example, discharges of generalized peak-wave complexes, lasting 1-2 seconds) does not always make it possible to accurately record the presence of an attack, synchronously with it. In these cases, a number of authors recommend using the term "subclinical epileptiform disorders on the EEG". The EEG pattern of a seizure can occur both generalized and regional. This is a highly specific phenomenon for epilepsy, even if it occurs without clinical symptoms. If there are paroxysms of unknown etiology in the clinic, this pattern proves their epileptic nature.

11. EEG status determined in the case of continued epileptiform seizure EEG patterns or frequently repeated seizure EEG patterns without restoration of the normal rhythm of the background recording between them. It should be noted that status EEG may not correlate with clinical symptoms of status epilepticus. A classic example of this is electrical status epilepticus of slow-wave sleep; a severe form of epilepsy with severe cognitive impairment, in which the frequency and severity of epileptic seizures may be minimal or there may be no seizures at all. Thus, even highly specific seizure EEG and status EEG patterns should only be considered in context with clinical data. Features of ictal EEG in various types of epileptic seizures within individual forms of epilepsy will be discussed in the following chapters.

6. Decoding and conclusion of EEG

Thus, we approached the interpretation of EEG abnormalities

These recommendations are not strict rules. They relate primarily to standard EEG. When describing more specialized recordings (neonatal recordings, electrocerebral silence), the presentation of technical details should be more complete - in accordance with ACNS standards (1 - "Minimum Technical Requirements (MTR) for Performing Clinical EEG"; 2 - "Minimal Technical Standards for Pediatric Electroencephalography "; 3 - "Minimum Technical Standards for EEG Recording in Suspected Cerebral Death").

The VEEG report should consist of 3 main parts:

1. introduction,
2. description,
3. interpretation, including
1. impression (opinion) regarding normality or degree of abnormality,
2. correlation of EEG data with the clinical picture.

1. Introduction.

The introduction should begin with a description of any special preparation, if any, undertaken prior to enrollment.

2. Description.

The description of the EEG should include all characteristics of the recording, including normal and abnormal, presented in an objective manner, avoiding as much as possible statements about their significance.

The goal is a complete and objective report that will allow other EEG specialists to reach a conclusion regarding the normality or degree of abnormality of the recording as described—without having to review the original EEG. This conclusion may differ from the original conclusion because it is subjective to a certain extent.

The description begins with the background activity, the dominant activity, its frequency, quantity (constant, transient), location, amplitude, symmetry or asymmetry, whether it is rhythmic or irregular. The frequency must be specified in Hz or cycles per second. In order to standardize the report, it is recommended to determine the amplitude in leads that include adjacent electrodes according to the 10-20 scheme. It is desirable, but not necessary, to estimate the amplitude in microvolts. This will avoid terms such as "low", "medium" and "high". Nondominant activity—frequency, quantity, amplitude, location, symmetry or asymmetry, rhythmicity or lack thereof—should be described using the same units of measurement as for dominant activity.

If tests were carried out, reactions to opening and closing the eyes, as well as voluntary, purposeful movements should be described. A description of the indication of symmetry or asymmetry, completeness or incompleteness, stability or instability is included.

Abnormal recordings, neonatal recordings, or recordings only during sleep, may not contain a clear dominant rhythm. In such cases, other types of activity (amplitude, frequency, etc.) must be described in any order. If the recording demonstrates significant interhemispheric asymmetry, characteristics for each hemisphere should be presented separately (dominant, non-dominant activity).

Background activity should be followed by a description of violations that are not related to background activity. The description includes: type of disorder (spikes, sharp waves, slow waves), prevalence (diffuse, local), topography or localization, symmetry, synchrony (intra- and interhemispheric), amplitude, temporal characteristics (continuous, periodic, episodic, or paroxysmal ) and the number of anomalous patterns. The number of abnormalities is described in a subjective manner because clinical EEG cannot accurately measure the number or ratio.

If the anomaly is episodic, attention should be paid to the absence or presence of periodicity between episodes, rhythmicity or irregularity of the pattern within each episode. It is necessary to provide a time range for the duration of the episodes.

Descriptions of activation procedures should include a statement about their quality (eg, good, fair, or poor hyperventilation, duration of sleep, sleep stages that were achieved during the study). It is necessary to indicate the type (glissando, step-by-step) photostimulation and stimulation frequency range. The effects of hyperventilation and photostimulation are described, including normal and abnormal responses. If hyperventilation or photostimulation was not performed, the reason must be stated. Because the referring physician assumes that these procedures are used by default, he may expect a description of their results—even if the need for them was not explicitly stated in the referral.

There is no need to indicate the absence of certain characteristics, with the exception of normal ones, such as low-amplitude fast activity, sleep spindles, etc. Phrases such as “absence of focal pathology” or “no epileptiform disorders” can only be used in the interpretation section - if there is obvious or the intended request of the referring doctor. They should not be used descriptively.

Artifacts should be described only in cases of doubt (e.g., there is still a possibility that they reflect cerebral activity) or when they are unusual in nature, interfere with the interpretation of the recording, and also when they have some diagnostic value (e.g., myokymia, nystagmus, etc. ).

3. Interpretation.

(I) Impression- this is the subjective opinion of a specialist about the degree of normality of the recording. The description of the recording is intended primarily for the electroencephalographer who uses it for subsequent inference, or another expert, and must be detailed and objective. The impression, on the other hand, is written primarily for the referring physician, and therefore should be as concise as possible. Most clinicians assume from previous experience that reading a detailed description does not provide them with significantly new information and therefore limit their interpretations. If it is too large and appears irrelevant to the clinical picture, the clinician may lose interest, ultimately reducing the usefulness of the entire EEG report. If a recording is considered abnormal, it is advisable to indicate the degree of abnormality to facilitate comparison between repeated studies. Since this part of the report is somewhat subjective, the degree of violation may vary from laboratory to laboratory. However, each laboratory should clearly define the criteria for the degree of impairment and strictly follow them.

After determining the degree of violations, it is necessary to indicate the reasons on the basis of which the conclusion is based. If there are several types of violations, it is advisable to limit yourself to a list of two or three main violations that are most typical for a given record. If you list all the violations, the most significant ones “dissolve” in the text and the significance of the conclusions is lost. If data from previous EEG recordings are available, it is necessary to include their comparison with the results of this study.

(II) Clinical correlation is an attempt to show how EEG data fits (or not) into the overall clinical picture. It can vary depending on who it is addressed to. For an addressee far from neurology or EEG, it should be more thorough and verified.

If the EEG is abnormal, it indicates cerebral dysfunction, since the EEG is a reflection of cerebral function. However, the phrase “cerebral dysfunction” may sound unnecessarily threatening and should only be used when the impairment is classified as “more than mild” and when there is sufficient clinical information to consider such a conclusion realistic in a given clinical context. In other cases, sentences like “The recording indicates mild irregularity in cerebral function” are acceptable. Certain EEG patterns are supportive for more or less specific clinical situations; delta focus may indicate a structural lesion in the appropriate clinical context; certain types of spikes or sharp waves support potential epileptogenesis. If the EEG abnormality is consistent with clinical information that provides a diagnosis or suspicion of a similar condition, it may be stated that the EEG findings are consistent with or confirm the diagnosis.

Digital methods of recording, generating and transmitting a report make it possible, if necessary, to include short sections of a real recording in the report, including examples of violations.

7. VEEG monitoring in assessing the effectiveness of anticonvulsant therapy

One of the main criteria for objectifying the effect of antiepileptic drugs is the change in the bioelectrical activity of the brain, recorded using EEG.

These changes are of a different nature and depend on the form of epilepsy and the therapy used.

In addition to the effect of anticonvulsants on epileptic activity, they also influence the pattern of background rhythmic activity. The changes in background rhythm that occur with long-term use of benzodiazepines and barbiturates are well described.

With the progressive course of the disease, an increase in the index of epileptic activity in the focus is noted.

Another marker of negative dynamics is the appearance of additional foci of epileptic activity. They can be dependent on the primary focus or exist independently.

Characteristics of the progradient course of the disease include the appearance of the phenomenon of secondary bilateral synchronization (SBS).

EEG criteria reflecting the positive effect of AEDs include: a decrease in the paroxysmal index in the focus, a decrease in the number of epileptic foci and regression of the VBS effect.

Dynamic VEEG studies during the period of discontinuation of therapy make it possible to assess the risk of recurrence of attacks with high accuracy.

8. Effectiveness of EEG monitoring

The reliability of the referral diagnosis “Epilepsy” was analyzed in primary patients admitted to the epileptology hospital (Scientific Center for Medical Care for Children, Moscow Department of Health).

The study group consisted of 1154 patients aged 0 to 18 years. All patients underwent the following examination methods: assessment of neuropsychic status, video-EEG monitoring lasting 6 hours or more, and, in most cases, MRI of the brain.

Results: The diagnosis of epilepsy was reliably confirmed in 643 patients (56%); in 240 (20.8%) patients, electroencephalographic patterns of epilepsy were not obtained, but the diagnosis was left as is, taking into account medical history and other examination methods; in 133 patients (11.5%) the diagnosis of “epilepsy” was removed; 46 (4%) patients were diagnosed with parasomnias; 39 (3.4%) had pseudoepileptic (psychogenic) seizures; 8 (0.7%) had tics; The group of patients of 45 (3.9%) people included children with affective-respiratory paroxysms, Tourette's syndrome, syncope, choreoathetosis/dystonia, migraine, autism, Munchausen syndrome, and masturbation.

Thus, in 23.2% (267) of patients the diagnosis of epilepsy was excluded. The most common paroxysmal conditions mimicking epilepsy were parasomnias and psychogenic seizures. We must also not forget about a large group (11.5% - 133 patients) of absolutely healthy children, the erroneous diagnosis of “epilepsy” in whom, in most cases, was associated with an incorrect interpretation of behavioral reactions characteristic of a particular age. In the vast majority of these cases, the reasons for overdiagnosis of epilepsy were insufficiently complete and accurate collection of anamnesis, incorrect interpretation of EEG results, and in some cases, psychological pressure from the patient’s relatives on the doctor.

9. Conclusion

Successful treatment of epilepsy directly depends on a timely and correct diagnosis. The use of uninformative diagnostic methods at the initial stage of treatment of epilepsy leads to difficulties in selecting adequate therapy and progression of the disease. In the EEG, this manifests itself in the form of the appearance of multiple secondary foci of epileptic activity, the development of the phenomenon of secondary bilateral synchronization in focal forms and a significant increase in the index of generalized discharges in generalized forms of epilepsy.

Often, the presence of epileptic seizures in a patient, despite their obvious curability, prompts the doctor to unreasonably introduce social restrictions and use polypharmacy in treatment.

On the other hand, unfounded statements of remission in patients with epilepsy also have unfavorable consequences for the patient, since clinically “invisible” types of seizures or epileptiform activity on the EEG persist.

The absence of changes in the recorded fragment of the waking EEG lasting up to 30 minutes (ILAE recommendations) may create a false impression of positive dynamics during treatment. Based on the data obtained, the doctor may erroneously state clinical-encephalographic remission. On the other hand, the detection of epileptic activity on the control dynamic EEG against the background of selected therapy may contain a fragment of epileptic activity, which the doctor mistakenly interprets as “negative dynamics”. In some cases, in short fragments of recording, EEG characteristics may appear as “normal” while seizures persist. At the same time, an objective analysis of the continued recording indicates that the nature of the patient’s bioelectrical activity did not change significantly. Errors in interpretation are associated with the alternation of normal and pathological EEG fragments.

It can be argued that an objective interpretation of EEG changes can only be carried out during VEEG monitoring.

The introduction of VEEG monitoring into the diagnostic and dynamic examination algorithm allows, using objective clinical and neurophysiological criteria, to timely diagnose the disease, assess the patient’s condition at different stages of treatment, optimize therapeutic tactics and avoid diagnostic errors in patients with epilepsy and epileptic syndromes.

Analysis of long-term follow-up of patients with epilepsy (adults and children) made it possible to develop and implement in specialized departments and offices a highly reliable, comprehensive clinical and neurophysiological approach to the differential diagnosis of epilepsy and convulsive syndromes, significantly improving the quality of therapy in this complex group of patients.