International training course on epilepsy. Clinical forms and classification of epilepsy /International Educations Course of Epilepsy. The clinical forms of epilepsy and their classification /

Epilepsy is a severe chronic disease characterized by recurrent, spontaneous seizures. The disease can be of a traumatic nature (occurs as a result of injury) or diencephalic (appears as a result of damage to the diencephalic structure of the brain).

In modern neurology, there are a large number of qualifications for epilepsy, which are based on the clinical and electroencephalographic manifestations of epileptic seizures. To record them, EEG and video monitoring are used.

The Yusupov Hospital offers a comprehensive diagnosis of epilepsy using these and other studies. By accurately identifying the type of disease, epileptologists select an individual treatment regimen that is most effective for a particular form of epilepsy. Modern medical equipment, innovative therapeutic techniques and an individual approach provide high treatment results – patients’ health status significantly improves, and the development of new epileptic seizures is prevented.

Classification of the disease

Epilepsy can be congenital (idiopathic) or acquired (symptomatic).
Symptoms of congenital epilepsy appear already in childhood or adolescence. The disease is characterized by a benign course and a favorable prognosis. The right approach to therapy can ensure complete elimination of the need to take medications. This form of pathology is not accompanied by damage to the brain matter. The excitability of the brain is explained by an increase in the electrical activity of neurons. Seizures of congenital epilepsy can lead to complete loss of consciousness.

Congenital epilepsy develops due to genetic defects in brain structures. As a result, the brain is constantly in convulsive readiness, since an attack can happen suddenly at any moment. The development of congenital epilepsy can be triggered by the following factors:

• birth injuries;
• hypoxia, fetal asphyxia;
• intrauterine infections during pregnancy.

Acquired epilepsy is a more complex and severe illness that can occur in people of any age and is difficult to treat. The disease occurs as a result of pathological changes in the brain caused by exposure to certain external factors. During an epileptic seizure, the patient does not lose consciousness, but cannot control a certain part of the body that was affected by the attack.

Acquired epilepsy occurs as a result of the influence of unfavorable factors on the brain, which in turn leads to the formation of an epileptic focus that generates an excess electrical impulse.

ILAE Classification 2021

From the point of view of a practicing physician, a classification is needed that distinguishes between epileptic seizures, forms of epilepsy, and epileptic syndromes. In turn, they highlight various specific reasons, for example, etiology, phenomenology of attacks, level of consciousness, etc. A detailed diagnosis is made, on the basis of which a treatment algorithm is built. The 2021 ILAE classification follows approximately this principle.

The 2021 ILAE classification distinguishes between two classifications—epileptic seizures [2] and forms of epilepsy [3]. This is caused by the presence of aspects in the disease itself (epilepsy) that go beyond the scope of convulsive manifestations (epileptic seizures).

The creators of the classification had to radically change the terminology in comparison with the previous classification, because they sought to make it understandable to various specialists. It was necessary to take into account ethical, linguistic, information and other requirements. It had to be applicable to different age groups.

The 2021 ILAE Working Classification of Epileptic Seizures has a basic and an extended version.

Figure 1 shows the 2017 ILAE working seizure classification.

One of the grounds for the proposed classification is the “focality” or “generalization” of the onset. A “focal” seizure originates from neural networks limited to one hemisphere. If it then becomes widespread, it may become "bilateral tonic-clonic" (now used instead of "secondary generalized"). In contrast, a generalized seizure quickly involves the neural networks of both hemispheres. It is necessary, however, to immediately explain the entire convention of such a division. The term “focal” originates in neuroanatomy (a focus of abnormal electrical activity in a certain area of ​​the cortex of one of the hemispheres of the brain). The term “generalized” comes from neurophysiology (a discharge of pathological epileptic activity on the electroencephalogram (EEG), recorded during an attack in all leads simultaneously). Thus, the division of attacks into “focal” and “generalized” is carried out according to different principles.

An additional difficulty is introduced by the insufficient understanding at the present stage of the pathogenesis of epilepsy in general and the patterns of spread of pathological excitation in the structures of the brain in particular (this is what explains the high percentage of failures in epilepsy surgery - the focus of epilepsy and the path of spread of pathological activity are located in the wrong place or not only where doctors think).

Despite significant progress compared to previous classifications, not all aspects remain clear to the clinician, especially the division of attacks into generalized and with unknown onset.

The 2021 ILAE Seizure Classification Update retained the same terminology from the 2001 ILAE glossary where possible, but introduced a number of new terms [4].

Terminology is always a subject of debate. In this case, the following innovations have been made: the term “partial” has been replaced with “focal”. Simple (without loss of consciousness) and complex (with loss of consciousness) partial seizures have disappeared. They became known as “focal with impaired awareness” and “focal without impaired awareness.” Instead of “secondary generalized tonic-clonic convulsions” - “focal seizure with transition to bilateral tonic-clonic.”

The doctor, inexperienced in psychological terminology, was completely confused about “consciousness” and “awareness.” The following terms are no longer used: “partial”, “simple partial”, “complex partial”, “mental”, “dyscognitive”, “secondary generalized tonic-clonic”. It must be taken into account that when translating any term into Russian, the meaning intended by the English-speaking author may be distorted.

The 2021 ILAE classification of epilepsy [3] is three-level (seizure type, epilepsy type, epileptic syndrome). The ideal option is to make a diagnosis at all levels and determine the etiology of epilepsy.

Figure 2 shows the structure of the 2017 ILAE classification of epilepsy. At the first level, having established that a seizure is epileptic, the doctor must determine its type in accordance with the classification of types (focal, generalized, unspecified).

At the second level, the type of epilepsy is determined based on the 2014 ILAE definition of epilepsy (focal, generalized, combined, unspecified). If it is impossible to identify the epileptic syndrome, i.e., transition to the third level, the type of epilepsy is the final diagnosis.

The third level is epileptic syndrome, which is a complex concept that includes the type of attack, characteristic signs on the EEG, frequent dependence on age, and provoking factors. There are currently no recognized or unrecognized ILAE syndromes (i.e., there are no “right” (eg, childhood absence epilepsy) or “wrong” (eg, Jeavons syndrome) syndromes—a wise decision by ILAE members).

The fourth level is establishing the etiology of epilepsy. An etiological diagnosis can be made at each stage of diagnosis.

The classification of epilepsy types according to their blocks does not fully correspond to the classification of seizure types. Among the types there are focal and generalized, which, as we have discussed, are actually difficult to differentiate. In the types of epilepsy, in the absence of “combined” seizures, “combined” epilepsy appears. Like a black mark, in all classifications there is the term “unspecified”, which is opposed to other types (in fact, due to the very limited understanding at the present stage of the etiology, pathogenesis and genetics of epilepsy, it is possible, without pretense, to classify most of the cases of the disease as “unspecified” ).

Local epilepsy

When diagnosing epilepsy, it is important for specialists to understand whether the seizure affects one of the brain hemispheres or the entire brain, thus identifying the type of seizure - partial or generalized.
Local (focal, partial) epilepsy can be simple or complex. With complex seizures, patients' consciousness is impaired, but with simple ones this does not happen. Simple seizures in local epilepsy are characterized by a variety of manifestations, which depend on the localization of epileptic activity in a particular area of ​​the cerebral cortex. Simple focal seizures are characterized by the occurrence of clinical convulsions in a certain part of the body and their further spread to neighboring areas.

Simple partial seizures can be:

• tonic – they are characterized by the patient adopting a forced posture and muscle tension. After a seizure, the muscles involved are temporarily weakened;
• sensory – patients experience illusions, hallucinations, any part of the body may become numb or tingling;
• vegetative - during attacks, piloerection, sweating, rapid heartbeat, and a feeling of a lump in the throat appear. With such seizures, patients experience a variety of mental disorders.

During complex seizures, patients' consciousness is impaired and they do not respond to external stimuli.
The duration of such an attack is usually from 30 to 90 seconds, after which drowsiness and fatigue appear. Complex seizures of local epilepsy must be distinguished from absence seizures. In the first case, the source is a focus of pathological activity, and the other is a primarily generalized seizure. The duration of focal seizures is often longer and they are characterized by confusion. Absence seizures are not accompanied by a similar phenomenon. The development of local epilepsy seizures is caused by focal damage to the cerebral cortex; they require different treatment than absence seizures.

New international classifications of epilepsies and epileptic seizures ILAE, 2021

In the winter of 2021, the International League Against Epilepsy (ILAE) updated the classification of this disease for the first time since 1989. Over the past 28 years, medical science has made huge leaps forward. There have been significant advances in understanding the basic aspects, genetics, diagnosis, clinical presentation, treatment and prognosis of epilepsy; this required a revision of the classifications already familiar and loved by every neurologist. Let's look at the key changes. According to the ILAE (2014) definition, “epilepsy is a disease of the brain corresponding to any of the following conditions:

• At least two unprovoked (or reflex) epileptic seizures with an interval of more than 24 hours;
• One unprovoked (or reflex) epileptic seizure and a probability of recurrent seizures corresponding to the overall risk of relapse (equal to or greater than 60%) after two unprovoked epileptic seizures in the next 10 years;
• Diagnosis of epileptic syndrome."

The first change affected the epilepsy classification system itself (Fig. 1).

Figure 1 | Algorithm for classification of epilepsy.

4 diagnostic levels were identified:

• At the first stage (level), the type of attack is determined.
• At the second stage (level), you should decide on the type of epilepsy.

It is worth clarifying here that the type of epilepsy diagnosed at this stage can become the final diagnosis if the doctor is not able to move to the next level - identifying the epileptic syndrome (usually in a situation where it is not possible to carry out the necessary methods of examining the patient) . If the necessary research methods are at the disposal of a specialist, then the transition to the third stage (level) is carried out.

• The third stage (level) is to establish the epileptic syndrome. What is epi syndrome ? A complex concept that includes the type of attack, characteristic signs on the EEG, frequent dependence on age, provoking factors and, in some cases, a certain prognosis. Epi syndrome often does not correspond to the etiology of epilepsy, but determines the tactics of patient management.
• The fourth stage (level) is to establish the etiology of epilepsy. According to the new classification, all epilepsies are divided into structural, genetic, infectious, metabolic, immune and unknown etiology. The etiological diagnosis should be considered at every stage of diagnosis, which may lead to significant changes in treatment.

The second change concerned the terminology regarding epileptic encephalopathy. According to the ILAE, epileptic encephalopathy is a condition in which epileptiform activity on the EEG contributes to cognitive and behavioral impairment. Moreover, both global and selective defects can increase over time. At the same time, syndromes related to encephalopathies can be either genetic (for example, Dravet syndrome) or acquired (West syndrome). So what is the essence of change in this context? Previously, it was believed that epileptic encephalopathies are accompanied by massive epileptiform activity, which is recorded on the EEG. But with the same Dravet syndrome, developmental disorders in the first 2 years of a child’s life precede the appearance of “massive epileptic volleys” and epileptic seizures.

Therefore, ILAE proposed using the term “developmental encephalopathy and epileptic encephalopathy,” which emphasizes the important role of the mutation in the development of cognitive deficits in children, and not just the dominant role of “massive” epileptimorphic activity. The term "developmental encephalopathy and epileptic encephalopathy" can be used in whole or in part if the situation requires it.

In addition to the above, the International League Against Epilepsy advises be withdrawn from use. This term in the new classification is replaced by the terms “self-limiting” and “responsive to pharmacotherapy”, which should be used in appropriate cases. In this case, “self-limited epilepsy” refers to the likely spontaneous resolution of the syndrome. The latest change also affected the classification of types of epileptic seizures (Fig. 2, 3), which is as important as the classification of epilepsy, since often the type of seizure directly indicates specific therapy. Also, a clear distinction between the types of epileptic seizures allows the doctor to specifically focus his attention on the mechanisms of development of various types of epileptic seizures.

Figure 2 | New classification of epileptic seizures.

Figure 3 | New classification of epileptic seizures (extended version).

This allows patients to be grouped by treatment approach, since AEDs are often approved for specific seizure types. The instructions for working with the classification provide a table of correspondence between old and new terms in the description of the types of epileptic seizures (Fig. 4).

Figure 4 | Old-new terminology of epi-attacks.

In the previous classification, its construction was based on an anatomical principle based on the identification of various attacks characteristic of the activation of a particular area of ​​the brain. At the moment, after numerous studies, the basis was based on a pathophysiological principle that characterizes epilepsy as a disease of neuronal networks, and not a symptom of local brain damage. An epileptic seizure is the development of transient signs and/or symptoms caused by abnormal excessive or synchronous neuronal activity of the brain. In summary, the following changes were made to the new classification:

• Exclusion from the classification of the term “partial” attack and replacement with “focal”;
• Introduction of the term “mindfulness” to characterize focal seizures. What does ILAE mean by the term mindfulness ? The patient who has suffered an attack is subsequently able to remember it and talk about the events that occurred during the attack;
• The following terms have been removed: “dyscognitive”, “simple and complex partial”, “secondary generalized”, “mental” ; instead of “secondary generalized” the term “focal with evolution into bilateral tonic-clonic” ;
• A focal seizure with preserved consciousness corresponds to the previous term "simple partial seizure ". A focal seizure with impaired consciousness corresponds to the previous term "complex partial seizure" . Impaired consciousness during any period of the attack makes it a focal attack with impaired consciousness;
• New types of focal and generalized seizures have been introduced: Focal - with automatisms, cessation of activity, hyperkinetic, vegetative, cognitive and emotional.
• Generalized - absence seizure with eyelid myoclonus, myoclonic absence seizure, myoclonic-atonic seizure and clonic-tonic-clonic seizure.

NB! By focal seizure, ILAE experts mean an epileptic seizure that develops from the neural networks of one hemisphere; under generalized - an attack that develops at some point in the neuronal network of one hemisphere, but with subsequent rapid involvement of bilaterally widespread neuronal networks. Consciousness and its disturbances remain a key feature for grouping focal ILAE attacks. However, the old classification used characteristics such as awareness and responsiveness to describe the disorder of consciousness. In the new classification, attention was also paid to self-awareness, that is, a person’s ability to distinguish himself as an individual in relation to other people. Responsiveness is not the same as awareness, since in some patients, during an attack, the lack of reactions is due to immobility, but at the same time they are able to perceive and remember what is happening around them. Experts clarify that retrospective assessment of consciousness using all 3 characteristics can be difficult, therefore, as mentioned above, the term “intact/impaired awareness” was introduced. Noteworthy is the inclusion in both sections (“focal” and “generalized” seizures) of epileptic spasms. This emphasizes the well-known fact that epileptic spasm can be both focal and generalized. Also included in both sections are tonic, clonic, myoclonic and atonic seizures, since according to the mechanism of development they are both focal and generalized.

When using the seizure classification, you can stop at any part of the classification. For example, an attack can be focal or generalized without further specification (when it is not possible to describe the attack in more detail). You can omit the term “without motor manifestations” (“non-motor”) and immediately use the terms “focal sensory”, “focal cognitive”, “focal emotional” and “focal vegetative” attack. A seizure with motor manifestations may be described as “focal motor,” “focal tonic,” or “generalized tonic.” And finally, the authors of the classification understand that not every epileptic seizure can be placed within its framework, therefore, the group “other type of attack” can be added to each category.

Sources

1. Scheffer IE et al. ILAE classification of the epilepsies: Position paper of the ILAE Commission for Classification and Terminology //Epilepsia. – 2021. – T. 58. – No. 4. – pp. 512-521.
2. Fisher RS ​​et al. Operational classification of seizure types by the International League Against Epilepsy: Position Paper of the ILAE Commission for Classification and Terminology //Epilepsia. – 2017. – T. 58. – No. 4. – pp. 522-530.
3. Fisher RS ​​et al. Instruction manual for the ILAE 2017 operational classification of seizure types //Epilepsia. – 2021. – T. 58. – No. 4. – pp. 531-542.

Generalized epileptic seizure

In a generalized epileptic seizure, both hemispheres of the brain are involved, so there are no precursors to its development. Generalized epileptic seizures are divided into the following types:

• typical absence seizures - they are characterized by short attacks of impaired consciousness, during which the patient’s gaze freezes or stops. At the end of the seizure, there is no confusion. Lack of treatment threatens multiple repetitions of absence seizures. As a rule, they begin to appear in childhood and continue into adulthood;
• atypical absence seizures - attacks are characterized by a pronounced beginning and end, long duration, mental retardation and motor impairment;
• clonic seizures – myoclonic jerks occur;
• myoclonic seizures – patients develop short, sudden convulsive twitches. The attack typically involves the head, neck, upper and lower extremities. Such attacks can be isolated or combined with other seizures;
• tonic seizures – bilateral short attacks of muscle tension develop in the limbs and torso;
• atonic seizures – the patient’s muscles suddenly and briefly lose their tone. There is a sudden drooping of the head or a fall of the patient. Despite the fact that consciousness is restored quite quickly, such seizures threaten to cause injury;
• generalized epileptic seizures - patients completely lose consciousness, their tonic tension in the muscles of the trunk, arms and legs disappears. Most often, the seizure is preceded by a piercing scream, the appearance of which is associated with the expulsion of air through the closed vocal cords. The muscles tense, after which a convulsive attack begins, which is characterized by severe muscle tension, which can be accompanied by fractures and dislocations. After an attack, a person has a headache and drowsiness.

Classification of epileptic seizures

Selected chapters from a lecture by E.D. Belousova

"Classification of epileptic seizures"

New concept

An epileptic seizure type is a seizure event that represents a unique pathophysiological mechanism and is associated with a specific anatomical substrate. Diagnostic group with its etiological, therapeutic and prognostic aspects Types of epileptic seizures and provoking factors for reflex seizures

• Self-limited types of seizures:

Generalized Focal (no division into simple and complex)

• Continuous types of seizures
• Provoking stimuli for reflex epilepsies

Self-limited epileptic seizures

• Generalized
• Focal

Terminological changes in the new ILAE diagnostic scheme

The term “partial” has been replaced by the term “focal” (considered synonymous)

A focal seizure is one “whose initial manifestations indicate initial activation of only part of one hemisphere.”

Terminology changes in the new ILAE diagnostic scheme Generalized seizures are those “whose initial presentation indicates more than minimal involvement of both hemispheres of the brain”

Generalized time-limited epileptic seizures

Tonic-clonic (including variants with onset from the clonic or myoclonic phase)

Clonic seizures:

• Without tonic features (features)
• With tonic features

Typical absence seizures (typical absence seizures) Atypical absence seizures Generalized tonic-clonic seizures

• Loss of consciousness
• Widespread muscle tension leading to clonic twitching
• Symmetry of clinical and encephalographic manifestations
• Post-ictal disturbances of cerebral metabolism and suppression of activity

Generalized tonic-clonic seizure

• Might be like that from the start
• May result from spreading epileptic activity from a focal seizure
• Can develop directly from another generalized seizure (tonic, clonic, myoclonic and absence seizure)

Duration of GTCS

• On average 1 minute
• If it is secondary generalized - up to 2 minutes

Phases of a generalized tonic-clonic seizure

• prodromal phase
• pre-tonic-clonic phase
• tonic-clonic phase
• early post-ictal phase
• post-attack recovery phase

Prodromal symptoms of GTCS

• Are not auras
• Can be observed several hours and even days before the attack
• These include headache, mood changes, anxiety, irritability, drowsiness, decreased attention, sleep disturbances, changes in appetite, myoclonus, dizziness, etc.

Pretonic-clonic phase of GTCS

• Isolated myoclonus or short clonic contractions are often observed (even with secondary generalization)
• There may be a turn of the head and eyes to the side, which does not always have localization significance

Tonic-clonic phase

• tension of the axial muscles and abduction of the eyeballs upward
• tonic tension extends to the limbs - raising and abducting the arms and flexion, adduction and external rotation of the legs
• then a period of tonic extension with forced exhalation (scream)
• gradually symmetrical twitching of the limbs

Tonic-clonic phase A short phase of flexor spasm is followed by a longer period of tonic extension, at which point the mouth closes and there may be injury to the tongue. At the same moment - a forced exhalation and sometimes a short cry. Tonic-clonic phase

• Blood pressure and heart rate may double
• Excessive sweating
• A gradual transition from their tonic phase to clonic with an intermediate period of “vibration” - tremor with a frequency of 8 Hz, then its slowdown - clonia

Tonic-clonic phase

• Each contraction leads to a short atony, gradually the periods of atonia become longer, and the contractions become less frequent.
• Towards the end of the clonic attack with a frequency of 1 Hz

Post-ictal phase

• Resumption of breathing
• Pupil dilation
• Tonic contraction of masticatory muscles and limbs
• At the onset of tonic contraction, involuntary urination

Post-ictal phase

• Gradual awakening with confusion and automatic behavior.
• Muscle weakness, headache
• Normalization of skin color, individual petechiae

Complications of GTCS:

• oral trauma: injury to the tongue, lips or cheek;
• abrasions, petechiae (including in the sclera);
• traumatic brain injury - skull fractures, brain contusions, epi- and subdural hematomas;
• vertebral compression fractures - 5 - 15% (between T3-T8 and thoracolumbar region). Asymptomatic in 80% of patients.
• aspiration pneumonia - due to tracheobronchial secretions, saliva and due to recurgitation of gastric contents;

Complications of GTCS:

• pulmonary edema - rare, relieved by oxygen inhalation;
• sudden death syndrome;

Seizure and post-seizure EEG during GTCS

• It is difficult to assess, since it is completely replaced by muscle and motor artifacts
• After the last clonic contraction, the EEG may be isoelectric or low-amplitude delta activity. The suppression phenomenon lasts up to two minutes. Triphasic waves or burst suppression may be present.
• The frequency and amplitude of the rhythm gradually increase and it normalizes approximately 30 minutes after GTCS. Slowing after an attack can last up to 24 hours.

Generalized clonic seizures

Combined with repeated bilateral clonic twitching of the limbs, sometimes they pass into the tonic phase and a clonic-tonic-clonic attack develops

Typical absence seizures are short (seconds) generalized epileptic seizures with a sudden onset and sudden end. Two components of absence are required: 1) disturbance of consciousness (clinically) 2) generalized spike-wave discharge with a frequency of 3 to 4 Hz (less than 2.5 Hz)

Typical absence seizures are a clinical and encephalographic concept. May be the only type of seizure (DAE), may be a rare and not the main type of seizure (JME). Unlike other types of attacks, they have selective sensitivity to AEDs. Drugs that are effective for focal seizures can aggravate absence seizures. What are typical absence seizures? Typical absence seizure

• Impairment of consciousness during absence seizure can be complete, incomplete and invisible (requires testing of cognitive functions).
• Absence seizures are often associated with other symptoms, autonomic disturbances, and regional (mouth and eye) or more widespread myoclonus (head, limbs, trunk)

Complex absence is a simple absence +

• clonic component (eyelids or corner of the mouth)
• atonic component (the head drops to the chest or objects fall out of the hands)
• tonic component (increased tone of flexors or extensors)
• automatisms (oroalimentary or in the hands)
• with vegetative symptoms

Classic absence seizure, characteristic of DAE (10 seconds) Atypical absence seizures are found only in the structure of severe symptomatic or cryptogenic epilepsies in children with learning difficulties, who also suffer from other types of seizures such as atonic, tonic and myoclonic. In atypical absence seizures, the beginning and end are not so sharp , as with a typical absence seizure, and more pronounced changes in muscle tone are noted Epileptic syndromes with atypical absence seizures

• Lennox-Gastaut syndrome
• Electrical status epilepticus during slow-wave sleep
• Myoclonic-astatic epilepsy

Atypical absence seizure

• May be atonic or tonic
• Tonic tension mainly in the muscles of the neck and face
• The degree of atony can be different (with severe atony, the child falls)
• Eyelid clones, autonomic manifestations, or automatisms may be present
• The degree of impairment of consciousness varies
• Duration from 5 to 20 seconds

Atypical absence seizure

• It is difficult to determine the beginning and end of an attack and its frequency (as a rule, attacks are observed in mentally retarded children; they are characterized by a more gradual beginning and end than typical absence seizures)
• The frequency of attacks ranges from several per day to continuous.

Atypical absence seizure

• EEG pattern - generalized spike-wave discharge with a frequency of less than 2.5 Hz
• The discharge is often asymmetrical, including irregular spike waves and slow waves
• As a rule, the main bioelectrical activity of the EEG is also changed in atypical absence

Generalized self-limited epileptic seizures

• Myoclonic absence seizures
• Tonic seizures
• Spasms
• Myoclonic seizures
• Massive bilateral myoclonus
• Myoclonus eyelids
• with absence seizures
• no absence seizures

Generalized self-limited epileptic seizures

• Myoclonic-atonic seizures
• Negative myoclonus
• Atonic attacks
• Reflex seizures in generalized epileptic syndromes

Myoclonic absence

• Impairments of consciousness of varying severity
• Myoclonic contractions of the shoulders, arms and legs against the background of tonic tension
• Tonic tension and myoclonus may be asymmetrical, the head may turn to the side
• Absence duration is from 8 to 60 seconds

Generalized tonic seizures

• axial
• axorisomelic
• global

Tonic axial seizure

• involvement of the muscles of the trunk, neck, masticatory and facial muscles
• there may be a brief holding of breath
• sometimes an attack of minor severity - raising the eyelids and averting the eyes

Tonic axial seizure most often occurs during sleep

Tonic axorisomelic seizures

• The same symptoms as with tonic axial, but
• + involving the proximal arms (shoulders rise, arms turn outward and spread apart) and, less commonly, legs

Global tonic seizure

• involvement of axial and limb muscles
• flexion of the arms at the elbow joints, pronation of the forearms, flexion of the hands and fingers, tonic flexion or extension of the legs
• often - falling

Generalized tonic attack

• May begin either suddenly or gradually, sometimes with massive bilateral flinching
• Duration from 10-15 seconds to 1 minute
• Consciousness is lost, but is restored as soon as the epileptic discharge stops
• Post-ictal stupor is short

Generalized tonic attack

• The structure of the attack may have a vibration component (several rapid clonic twitches) towards the end of the tonic tension
• If the attack is global, the patient may fall
• Autonomic symptoms - tachycardia, facial flushing, dilated pupils, apnea
• Sometimes after the tonic phase - gesture automatisms

Generalized tonic seizures

• Rare in idiopathic forms
• Often found in Lennox-Gastaut syndrome, in the structure of progressive myoclonus epilepsy
• Their frequency will increase during sleep (nonREM sleep phase), and may be observed in clusters upon awakening

Generalized tonic seizures may resemble GTCS, but:

• no opisthotonus posture;
• clonic contractions are single;
• post-ictal stupor is short;
• the attack is generally shorter

EEG changes during a generalized tonic seizure

• Fast activity or fast rhythms with a frequency of 9 - 10 seconds or more of small amplitude
• As the attack progresses, the frequency decreases and the amplitude increases EEG during a tonic attack

Spasm A short strong contraction of the axial muscles (flexion, extension or mixed). Duration - a fraction of a second, serial (from 5 to 50 attacks in a series), several series per day, often upon awakening. They can be symmetrical or asymmetrical, with deviation of the head or eyes to the side, or only half of the body is involved in spasm. The spasm can only be manifested by briefly moving the eyes upward. The series may be preceded by a stop in the child's activity. The child often cries after each cry.

Spasm The most common age of onset of spasms is from 3 to 12 months, peaking at the age of 6 months. Spasms can occur immediately after birth or after 12 months, including adulthood. EEG spasm - high amplitude slow wave or low amplitude fast rhythms. In some cases, focal activity may be recorded that precedes, follows, or occurs during a series of seizures. Myoclonic seizures are those in which the main component is single or repeated epileptic myoclonus

Myoclonus

• Sudden, involuntary, short (lightning-fast) muscle contraction of central origin.
• The amplitude can vary from small (no movement in the joint) to large (leads to movements of the limbs, head and torso)

Myoclonus may be

• generalized (whole body)
• focal (body part)
• regional (two or more body parts)
• in individual muscles and muscle groups
• bilateral and unilateral
• single or repeated
• rhythmic or arrhythmic

Myoclonus may be

• positive (muscle contraction)
• negative (inhibition of muscle contraction)
• both against the background of preserved consciousness and with its impairment (with massive myoclonus)

Myoclonus can be generated at the level:

• cerebral cortex
• cerebellum
• brain stem
• pinna brain

Myoclonus may be

• epileptic
• non-epileptic

Epileptic myoclonus One that is accompanied by depolarization

Seizure EEG High amplitude discharge of multiple fast spikes followed by a slow wave Massive bilateral myoclonus A generalized type of seizure that consists of a single or series of axial jerks of the entire body, but mainly the upper extremities, accompanied by a generalized spike-wave or polyspike-wave discharge. The main type of seizure in benign myoclonic epilepsy, Dravet syndrome and juvenile myoclonic epilepsy.

Myoclonus of the eyelids with absence seizures

• A type of seizure with myoclonic contractions of the eyelids and short absence seizures. Mainly triggered by closing the eyes and flashing lights.
• Occurs in symptomatic, probably symptomatic and idiopathic epileptic syndromes.
• Most authors believe that eyelid myoclonus with absence seizures is a distinct idiopathic epileptic syndrome, genetically determined, age-dependent, in children with normal intelligence, and possibly lifelong (seizures continue into adulthood)

Myoclonus of the eyelids occurs in the first seconds of the discharge on the EEG and consists of repeated, often rhythmic, fast (4-6 Hz) myoclonic contractions of the eyelids. Myoclonus can be of different amplitudes and strengths, their number in an attack is also different (usually more than three contractions). As a rule, there is a tonic tension of the eyelids, upward movement of the eyes and their vertical twitching, simultaneously with twitching of the eyebrows and head; the head and eyes can be moved to the side. Myoclonus of the eyelids may be associated with myoclonus of the arms. A myoclonic-atonic attack is a special variant of myoclonus, when a wince is immediately followed by a loss of muscle tone. Manifested by falling after a start. The main type of attack in myoclonic-astatic epilepsy is a generalized spike, and atonia is a generalized slow wave. Some attacks are accompanied by a series of spikes, followed by slow waves with a frequency of about 3 Hz, lasting no more than 1 second. Negative myoclonus is a movement disorder characterized by a sudden and abrupt stop in muscle activity. At this moment, the EMG shows a short period of silence (less than 500 ms), before which myoclonus is not recorded. Can be observed in physiological and pathological conditions

Epileptic negative myoclonus is a cessation of muscle activity (without previous myoclonus), tied in time to a spike on the EEG. It is never the only type of seizure, combined with partial seizures, with absences and with atonic seizures, tonic and GTCS, with spasms.

Epileptic negative myoclonus

• Can be observed in rolandic epilepsy, electrical status epilepticus during the slow-wave sleep phase, in children and adults with symptomatic epilepsies (mitochondrial encephalopathies, consequences of anoxia during childbirth, vascular malformations, PME, neuronal migration disorders
• May be a complication of AED therapy (cases have been described where myoclonus was induced by carbamazepine, oxcarbazepine, phenytoin, lamotrigine and valproic acid)

Atonic attack

An attack characterized by a sudden loss or decrease in muscle tone, which can be fragmented, tied to a specific segment of the body (limb, jaw, head) or massive, leading to a fall. Atonia or decreased muscle tone is not preceded by myoclonus or tonic tension

Atonic attacks

• Usually considered to be a generalized type of seizure, but may also result from a focal (frontal) discharge
• Generalized atonic attack is rare

There are two types of atonic attacks:

• Short (if there is a loss of consciousness, it is very short, and the child can get up immediately after the fall)
• Prolonged atonic attacks (akinetic attacks) - loss of consciousness and generalized atony lasting from 1 to several minutes (the patient lies unconscious and motionless)

Seizure pattern of generalized atonic seizure

• Generalized polyspike-wave discharge, loss of muscle tone usually occurs in a slow wave.
• Low- or high-amplitude fast activity, flattening of the curve, or burst of polyspikes followed by spike-wave activity

Atonic attacks can occur when

• Lennox-Gastaut syndrome
• Myoclonic-astatic epilepsy
• Atypical benign partial epilepsy of childhood

Changes in the new ILAE diagnostic scheme There is no division of focal seizures into simple and complex Focal sensory seizures

• With elementary sensory symptoms (eg, occipital and parietal epilepsies)
• With experiential sensory symptoms (eg, attacks occurring at the junction of the temple, crown and occiput)

Simple partial epileptic seizures with somatosensory symptoms

• numbness, tingling, tickling, "pins and needles"
• disturbances in temperature (burning, cold), pain sensitivity, inability to move in a certain way. body parts
• spread like an epileptic march from distal to proximal parts
• observed predominantly contralateral to the lesion

Simple focal epileptic seizures with somatosensory or specific sensory symptoms

• somatosensory
• visual (amaurosis, illusions, simple and complex hallucinations)
• auditory (sounds - grinding, creaking, auditory hallucinations)
• olfactory (smell, usually unpleasant)
• gustatory (sensations of bitter, sour, sweet)
• attacks of dizziness

Focal motor seizures

• With elementary clonic motor symptoms
• With asymmetrical tonic motor symptoms (eg, seizures associated with the supplementary motor cortex)
• With typical (temporal lobe) automatisms (eg, seizures associated with the medial temporal lobe)
• With hyperkinetic automatisms
• With focal negative myoclonus
• With inhibitory motor symptoms

Focal seizures (slide 3)

• Seizures associated with the posterior neocortex
• Neocortical temporal lobe seizures
• Gelastic seizures
• Hemiclonic seizures
• Secondary generalized seizures
• Reflex seizures in focal epileptic syndromes

Seizures associated with the posterior neocortex are divided into

• Seizures originating in the occipital lobe
• Seizures originating in the parietal lobe

Seizures originating in the occipital lobe

Subjective symptoms: elementary visual hallucinations, amaurosis, sensation of movement of the eyeballs, diplopia Objective symptoms: eye deviation, nystagmus, blinking Seizures arising in the occipital lobe Typical for benign occipital epilepsies of childhood, celiac disease with calcifications in the occipital lobe and for malformations

Seizures originating in the parietal lobe

Subjective symptoms - paresthesia, pain, feeling that the limb does not belong to the patient (rarely), dizziness (temple-vertex), taste hallucinations (can also occur with a focus in the anterior temporal lobe), sensation of body movement, with a focus in speech dominant hemispheres various disorders of reading, writing and speech Objective symptoms - a variant of the spread of excitation Secondary generalized seizure Prolonged (continuous) epileptic seizures

• Generalized status epilepticus
• Focal status epilepticus

Generalized status epilepticus

• Generalized tonic-clonic status epilepticus
• Clonic status epilepticus
• Absence status epilepticus
• Tonic status epilepticus
• Myoclonic status epilepticus

Focal status epilepticus

• Epilepsy partialis continua Kozhevnikov
• Aura continua
• Limbic status epilepticus (psychomotor status)
• Hemiconvulsive status with hemiparesis

Epilepsy partialis continua Kozhevnikov Almost constant rhythmic muscle contractions that occur in some limited part of the body and persist for hours, days and even years. The frequency of contractions is 1-2 per second. Contractions may persist during sleep. In 60% of cases they are combined with other attacks (VHTS and complex focal ones). Focal brain damage (tumors, vascular abnormalities, infections) Kozhevnikov's partialis continua epilepsy EEG may demonstrate focal spikes and slowing in the central regions, but this is not a specific encephalographic pattern Kozhevnikov's partialis continua epilepsy is observed in children with

• infections (for example, subacute measles encephalitis, viral encephalitis or meningoencephalitis);
• cortical dysplasia;
• mitochondrial diseases (especially MELAS syndrome and Alpers disease);
• tumors;
• inborn defects of metabolism

Aura continua

The term limits conditions with subjective experiences without visible motor components of type 4:

• somatosensory
• with special symptoms (visual, auditory, dizziness, gustatory and olfactory)
• with predominantly autonomic symptoms
• Abdominal aura continua has been described in children

Limbic status epilepticus (psychomotor status)

Epileptic state that lasts at least 30 minutes with a variety of clinical symptoms, behavioral disturbances, and psychosis-like symptoms, especially complex hallucinations, and impairment of consciousness (at least intermittently) Hemiconvulsive status with hemiparesis

The first symptom of this syndrome is sudden prolonged hemiconvulsions (status) in a child without previous seizures at the age of 5 months. up to 4 years, sometimes associated with fever. The status is followed by the development of hemiplegia (in more than 80% of cases it remains constant). After 1-3 years, focal epilepsy develops (hemiconvulsions-hemiplegia-epilepsy syndrome) Provoking stimuli for reflex epilepsies

• Visual: flashing light, color, pattern, etc.
• Thinking
• Music
• Food
• Praxis
• Reading
• Somatosensory
• Proprioceptive
• Hot water
• Fright

Types of epilepsy. Seizure symptoms

The classic manifestation of epilepsy is the presence of seizures.
They arise unexpectedly and do not always depend on environmental factors. In certain cases, it is possible to predict the occurrence of an attack based on the patient’s complaints of general malaise. He may be tormented by headaches, poor sleep, lack of appetite, and irritability. During an attack, convulsions occur, during which the head is thrown back, the limbs and torso are stretched, breathing is held, and the veins of the neck swell. Such convulsions are called tonic, their duration is about 20 seconds. They are followed by clonic convulsions, which manifest themselves in jerking movements. This phase lasts up to 3 minutes. The patient may experience foaming at the mouth mixed with blood, this is due to the accumulation of saliva in the mouth and possible biting of the cheek or tongue.

Modern medicine knows many types of epilepsy. There are main types of epilepsy:

• absence epilepsy. Characterized by a lack of reaction to events happening around;
• Rolandic epilepsy. It is characterized by numbness of the skin, spasms of certain parts of the body, and excessive salivation. Mostly boys aged 8-10 years are affected;
• myoclonic epilepsy. Characterized by the presence of epileptic seizures, myoclonus (muscle contractions), sometimes mental disorders are noticeable;
• post-traumatic epilepsy. Characterized by the presence of seizures as a result of traumatic brain injury;
• alcoholic epilepsy. Typical for people suffering from alcohol addiction. Manifested by convulsions and loss of consciousness. After the seizure ends, the patient may fall asleep for several hours;
• epilepsy of newborns;
• temporal lobe epilepsy. It is chronic in nature with gradual progression;
• epilepsy in children. Seizures may not be related to epilepsy. Careful diagnosis is necessary;
• non-convulsive epilepsy. Characterized by the absence of symptoms expressed by convulsions. It manifests itself as a lack of reaction to external stimuli, a blank look, and loss of consciousness.

Epilepsy, regardless of type, requires careful treatment.
Diagnosis and treatment of epilepsy is carried out by epileptologists at the Yusupov Hospital. Make an appointment

Status epilepticus

Status epilepticus is said to occur when seizures are repeated multiple times, so often that consciousness does not have time to recover between them.
Patients experience impaired hemodynamics and respiratory function, and twilight consciousness appears. Convulsive attacks are accompanied by soporous and comatose states, seriously threatening the life of the epileptic. In the tonic phase, a spasm of the respiratory muscles occurs, and apnea appears with the characteristic symptoms listed above. There is an appearance of increased and shallow breathing associated with hypoxia, which is accompanied by hypocapnia. With this condition, epileptic activity increases and the duration of the seizure increases.

Patients who have fallen into a coma suffer from pharyngeal respiratory paralysis with loss of the pharyngeal reflex. In the respiratory tract, salivary secretion accumulates, as a result of which breathing worsens and cyanosis occurs. Hemodynamics change, heart rate increases, blood pressure increases, myocardial ischemia develops, metabolism is disrupted, resulting in metabolic acidosis, and intracellular respiration is disrupted.

Diagnostics

If you have epilepsy attacks, you should immediately seek help from a neurologist.
The Yusupov Hospital has an epileptologist who specializes in this disease. The doctor will conduct diagnostics using modern equipment. At the Yusupov Hospital, the following examination methods are used for this: encephalography, neurosonography, MRI, CT, Dopplerography of cerebral vessels, ultrasound if necessary. The doctor will determine the exact form and cause of the disease and prescribe appropriate treatment.

It is important to follow the exact recommendations of your doctor to achieve the maximum effect of treatment. According to statistics, with the correct course of treatment, attacks will soon decrease and soon disappear altogether.

Institute of Child Neurology and Epilepsy

1. Epilepsy and epileptic syndromes associated with a specific localization of the epileptic focus (focal, local, partial epilepsy): 1.1. Idiopathic locally caused epilepsy (associated with age-related characteristics). 1.2. Symptomatic locally caused epilepsy. 1.3. Cryptogenic locally caused epilepsy.

2. Generalized epilepsy and epileptic syndromes: 2.1. Idiopathic generalized epilepsy (associated with age-related characteristics). 2.2. Generalized cryptogenic or symptomatic epilepsy (associated with age-related characteristics). 2.3. Generalized symptomatic epilepsy and epileptic syndromes: 2.3.1. Generalized symptomatic epilepsy of nonspecific etiology (associated with age-related characteristics). 2.3.2. Specific syndromes.

3. Epilepsy or epileptic syndromes that cannot be classified as focal or generalized: 3.1. Epilepsy or epileptic syndromes with generalized and focal seizures. 3.2. Epilepsy or epileptic syndromes without specific manifestations characteristic of generalized or focal seizures.

4. Special syndromes: 4.1. Seizures associated with a specific situation. 4.2. Single seizures or status epilepticus.

Symptomatic refers to epileptic syndromes with a known etiological factor. As the name implies, symptomatic epilepsy is one of the symptoms of another disease of the nervous system: tumors, dysgenesis, metabolic encephalopathy, a consequence of hypoxic-ischemic brain damage, etc.

Cryptogenic (from the Greek criptos - hidden) forms of epilepsy are called syndromes with an unrefined, unclear etiology. Cryptogenic forms are purported to be symptomatic, but current neuroimaging techniques have failed to detect structural abnormalities in the brain (136). Today, most authors are inclined to believe that it is more correct to interpret cryptogenic forms of epilepsy as “probably symptomatic.” This thesis is reflected in the classification of epileptic syndromes proposed in 2001.

There are also partial, generalized forms and syndromes that have features of both generalized and partial.

Separately, idiopathic forms of epilepsy are distinguished . The concept of idiopathic epilepsy comes from the Greek words “idios” (own) and “patos” (painful) and means that this form of epilepsy is caused by dysfunction of the brain itself. According to Delasiauve (122), one of the first to propose the term idiopathic epilepsy at the beginning of the 19th century, cases with no signs of organic brain damage should be included in this group. Tissot (298) first suggested in 1770 that in idiopathic epilepsy “there is a predisposition of the brain to seizures.”

In the structure of idiopathic forms of epilepsy, there is a division into idiopathic partial and idiopathic generalized epilepsy syndromes.

Treatment

Epilepsy is a serious stress that is experienced by both the patient’s loved ones and himself.
A person experiences constant fear, waiting for each new attack, and as a result he develops depression. Therefore, neurologists at the Yusupov Hospital make every effort to help patients suffering from epilepsy, selecting treatment with the most modern antiepileptic drugs that can prevent the development of new seizures. In the fight against the disease, epileptologists at the Yusupov Hospital adhere to the following therapeutic principles:

• early start of treatment;
• continuity;
• complexity;
• continuity;
• individual approach.

Treatment of patients with epilepsy in the neurology clinic of the Yusupov Hospital is aimed at achieving the following goals:

• preventing the development of new epileptic seizures;
• relief of pain during attacks;
• reducing the frequency of epilepsy attacks;
• stopping medications or reducing side effects from their use;
• training relatives of an epileptic in the correct handling of the patient;
• conducting socio-neurological rehabilitation to improve the patient’s quality of life;
• the use of complex therapy for patients suffering from epilepsy and related diseases.

The Neurology Clinic of the Yusupov Hospital provides comprehensive, regular and long-term treatment for epileptic seizures.
It consists of dehydration, anticonvulsant, restorative and resorption procedures. Before starting treatment, a team of neurologists and diagnosticians at the clinic determine the type of epileptic seizures and the etiology of epilepsy. For drug therapy, the most optimal drug is selected, the dosage of which is constantly increased until the attacks completely stop. If taking the drug does not achieve the desired result, additional medications are prescribed.

The effectiveness of therapy largely depends on the actions of the patient himself - his compliance with all the recommendations of the attending physician. Interruption of the drug may result in status epilepticus.

In the neurology clinic of the Yusupov Hospital, during the treatment of epilepsy, doctors with extensive experience in treating all types of diseases use the latest technologies and the latest generation antiepileptic drugs. To conduct diagnostics and consult a neurologist or epileptologist at the Yusupov Hospital, you must make an appointment by phone or on the clinic’s website.

The presence of a modern classification of epileptic seizures and epilepsies is an indispensable condition for effective practical work and scientific activity in the field of epileptology. The classification is necessary for physician judgment, education, prognosis, presurgical evaluation of patients with drug-resistant epilepsy, clinical trials of antiepileptic drugs (AEDs), epidemiological studies and, finally, to ensure understanding between the different specialists involved in the evaluation and treatment of patients with epilepsy ( neurologists and psychiatrists, geneticists, neurosurgeons, general practitioners, social workers, etc.).

The modern classification of epileptic seizures and syndromes should undoubtedly reflect the current level of knowledge in epileptology, be logical and understandable, easy to use and flexible (i.e., it should be possible to change it when new knowledge becomes available).

The debate about what the classification should be is not new. J. Jackson also wrote that there are two opposing trends in creating a classification of diseases, including epilepsy: one is towards simplification, the other is towards complication of classification. A simple classification is needed by some specialists, a complex one by others. J. Jackson clearly explained this contradiction using the example of a gardener and a botanist. For a gardener, all plants are divided into herbs, flowers, shrubs and trees. This simple division is enough for him to successfully work in the garden. A botanist’s attitude towards plants is more complicated: in addition to the banal division into large groups, he is also interested in particulars - species, subspecies, etc. A botanist needs such a complex classification for his work, for example, for plant breeding [1]. The same thing happens when creating a classification of such a heterogeneous group of diseases as epilepsy. On the one hand, a general practitioner who does not specialize in epileptology should be able to diagnose epilepsy at the patient’s bedside (without resorting to additional diagnostic methods) and prescribe adequate treatment. On the other hand, medical specialists working in large level 4 epileptology centers, with the help of special knowledge and modern diagnostic technologies (high-field and high-resolution magnetic resonance imaging (MRI), positron emission tomography (PET), long-term video-electroencephalography (EEG) monitoring, magnetoencephalography) can formulate an accurate diagnosis for rare forms of epilepsy, if necessary, confirming it with molecular genetic research data. It is obvious that scientists conducting genetic research in the field of epilepsy need one classification, epidemiologists another, social workers a third, etc. Unfortunately, this is a basic contradiction between a large amount of knowledge and a rather rigid system in which it needs to be placed, not yet overcome.

For more than two decades, the International Classification of Epilepsies and Epileptic Syndromes, adopted in 1989, has been used in practical and scientific activities. In this classification, epilepsies were divided into partial and generalized, and at the second level, each of the main groups was divided into symptomatic, cryptogenic and idiopathic. In addition to the two main sections, epilepsies with signs of partial and generalized, and a section “Specific syndromes” were distinguished, which included febrile seizures, seizures with metabolic disorders, isolated seizures or isolated status epilepticus. The International Classification of Epilepsies and Epileptic Syndromes (1989) is well known to practitioners and is described in detail in many domestic monographs on epilepsy [2-4]. Undoubtedly, since its creation there have been significant changes in the understanding of the basic aspects, genetics, diagnosis, clinical picture, treatment and prognosis of epilepsy. It has become obvious that the International Classifications of Epilepsies and Epileptic Seizures (1989) are outdated and need to be revised. The International League Against Epilepsy (ILAE), whose important contribution to epileptology is the development and implementation of classifications and terminology, decided in July 1997 that it was necessary to revise previous classifications of epileptic seizures and epilepsies. In 2001, ILAE published a draft “Diagnostic scheme for people with epileptic seizures and epilepsy” [5], and in 2010 in the journal “Epilepsia” - “Revisiting the terminology and concept of organization of epileptic seizures and epilepsies”, in which “new terminology and new concepts complement the old classification and bring it into line with the modern understanding of epilepsies in clinical practice” [6]. Due to the difficulties of creating a classification, it was proposed to classify epilepsies according to “a mobile scheme in different ways depending on the tasks (by age, by etiology, by type of seizures and EEG features).” Subsequently, many positions of the document were revised and found their completion in the new classification. All this time, active work was going on to discuss various aspects for everyone who wanted to participate in the discussion on the ILAE website, after which in the summer of 2021 the discussion on the website was closed. Two outcome documents were published in 2021: The ILAE Classification of Epilepsies: A Position Paper of the ILAE Commission on Classification and Terminology [7] and the ILAE Working Classification of Seizure Types: A Position Paper of the ILAE Commission on Classification and Terminology [ 8]. This review presents the main content of both classifications, deliberately without commenting on their provisions and terminology.

According to the ILAE definition (2014) [9], “epilepsy is a disease of the brain corresponding to any of the following conditions:

1. At least two unprovoked (or reflex) epileptic seizures with an interval of more than 24 hours.

2. One unprovoked (or reflex) epileptic seizure and a probability of recurrent seizures corresponding to the overall risk of relapse (equal to or greater than 60%) after two unprovoked epileptic seizures in the next 10 years.

3. Diagnosis of epileptic syndrome.”

New classification of epilepsies

The classification contains several levels, which is due to the large variability of available methods for examining patients with epilepsy in the world. At the first stage (level), the type of attack is determined: focal, generalized or with an unknown onset (see the section “Classification of epileptic seizures” for more details).

At the second stage (level), you should decide on the type of epilepsy: focal, generalized or combined focal and generalized, or unknown.

For generalized epilepsy

characterized by the presence of generalized spike-wave activity on the EEG, a spectrum of seizures, including absences, myoclonic, atonic, tonic and tonic-clonic seizures. Diagnosis is made based on clinical manifestations and typical interictal discharges.

Focal epilepsies

- these are epilepsies with one or more foci, as well as epilepsies involving one hemisphere of the brain. They are characterized by a whole spectrum of clinical manifestations and focal epileptiform discharges on the EEG.

Combined generalized and focal epilepsies

- epilepsy with focal and generalized types of seizures, while the activity on the EEG can be of any kind: both focal and generalized discharges can be recorded. A classic example of such epilepsy is Dravet syndrome [7].

The type of epilepsy diagnosed at the second stage can become the final diagnosis if the clinician is not able to move to the next level - identifying the epileptic syndrome (usually in a situation where the doctor does not have the necessary methods for examining the patient). As an example, a fairly common situation of temporal lobar epilepsy without changes in the interictal EEG is given. In such a situation, the diagnosis “focal epilepsy of unknown etiology” may be considered sufficient. Another example is the presence of a generalized tonic-clonic seizure in a 5-year-old child with generalized spike-wave activity on the EEG (the diagnosis of “generalized epilepsy” is eligible). Or a clinical situation when a 20-year-old girl with focal seizures with impaired consciousness and absences, as well as focal and generalized activity on EEG and normal MRI of the brain, can be diagnosed with “combined focal and generalized epilepsy” [7].

Unclassified epilepsy

(unknown) - epilepsy in which it is impossible to determine whether it is focal or generalized, and EEG data is not available or is not very informative.

The third stage (level) is to establish the epileptic syndrome [7]. Epileptic syndrome

is a set of characteristics, including the type of attack, EEG and neuroimaging data, it often has an age-dependent nature, provoking factors, chronological dependence and, in some cases, a certain prognosis. There may be characteristic comorbidity - intellectual and psychiatric disorders. The syndrome may also have associated etiological, prognostic and therapeutic implications. It often does not correspond to the etiology of epilepsy, but determines the tactics of treatment and monitoring of the patient. There are quite a few well-described epileptic syndromes (infantile absence epilepsy, West syndrome, Dravet syndrome, etc.), but ILAE has never attempted to classify them.

Despite the lack of classification of syndromes, among generalized epilepsies there is a generally recognized and frequently occurring subgroup - idiopathic generalized epilepsies.

These include childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy and epilepsy with isolated generalized tonic-clonic seizures.
The Greek term " idios
" translates as "oneself", "one's own", "personal" and implies some kind of genetic etiology. Within the framework of the new classification, this group could be called “genetic generalized epilepsies,” but doctors expressed a desire to preserve the usual terminology, so it was decided to use both names of the subgroup.

Another distinguished group of syndromes is age

(a more accurate translation of “self-limited” from the English self-limited)
focal epilepsy
. These include benign epilepsy of childhood with centrotemporal spikes (synonyms - age-dependent epilepsy with centrotemporal spikes, Rolandic epilepsy), Panayotopoulos syndrome, Gastaut syndrome, as well as individual frontal lobe, temporolobar, and parietal lobe epilepsies with onset in adolescence and even in adulthood.

The fourth stage (level) is to establish the etiology of epilepsy. According to the new classification, all epilepsies are divided into structural, genetic, infectious, metabolic, immune and unknown etiology.

Structural epilepsies

- epilepsies in which a structural defect is likely to be the cause of the epilepsy.
As an example, epilepsy is given that develops after injury, stroke, infection, against the background of a malformation of the brain. Epilepsies caused by hippocampal sclerosis, hypothalamic hamartoma and atrophy characteristic of Rasmussen's syndrome are especially significant, since neurosurgical intervention is effective for them. It is emphasized that structural epilepsies can be both genetic and acquired. Thus, a malformation of the brain in the form of polymicrogyria can be caused by both a mutation in the CPR56
and intrauterine cytomegalovirus infection. In a situation where epilepsy is both genetic and structural (for example, epilepsy in tuberous sclerosis), both terms (“genetic” and “structural”) have a right to exist.

Genetic epilepsy.

The concept of genetic epilepsies is that the disease is caused by a specific mutation.
This cannot always be confirmed by genetic testing; sometimes the statement is based on family history (for example, there is an autosomal dominant pattern of inheritance). Most known mutations causing epilepsy show clinical heterogeneity, and most genetic epilepsy syndromes show genetic heterogeneity. If there is a complex type of inheritance, which involves mutations in many genes in combination with or without the influence of environmental factors, we can talk about genetic predisposition (a factor insufficient for the development of epilepsy). Among the environmental factors mentioned are lack of sleep, stress and infections. Statement of the genetic etiology of epilepsy does not mean inheritance of the disease. Many mutations that cause the development of both severe and non-severe epilepsies are de novo
, and, therefore, the prognosis for further childbearing in such families is favorable. But the patient himself, who has this mutation, can pass it on by inheritance.

Infectious epilepsies

- conditions that are a direct consequence of a specific infectious disease; their clinical picture is dominated by epileptic seizures. Epileptic seizures in the acute period of meningitis or encephalitis are not epilepsy. Infectious etiology is considered the most common. In certain regions of the world, epilepsy can be caused by neurocysticercosis, tuberculosis, HIV infection, subacute sclerosing panencephalitis, toxoplasmosis and other intrauterine infections, including the Zika virus. Epilepsy can develop after an infection has ended, for example after viral encephalitis. Establishing an infectious etiology is important, as this is followed by specific therapy.

Metabolic epilepsy

are a direct result of a known or suspected metabolic disorder, with epilepsy dominating the clinical picture. These are often well-known metabolic disorders such as uremia, porphyria, amino acid metabolism disorders, and pyridoxine-dependent seizures. Metabolic epilepsy can be acquired or genetic. Specific therapy is also possible with it.

Immune epilepsies

- a direct consequence of immune disorders and the main clinical manifestation of the disease. This diagnosis is possible when there is evidence of autoimmune inflammation in the central nervous system. Examples are NMDA receptor antibody encephalitis and limbic encephalitis. Specific therapy (immunocorrection) is also possible.

It should be noted that the autoimmune mechanisms underlying such epileptic syndromes, such as Rasmussen's syndrome, form structural epilepsy. In turn, infectious agents often induce autoimmune processes that lead to brain damage with clinical manifestations in the form of epilepsy (thus, epilepsy combines infectious, autoimmune and structural etiologies). This is observed in a number of acquired cases of Duke-Davidoff-Masson syndrome, manifested by cerebral hemiatrophy, seizures, hemiparesis, facial asymmetry and learning difficulties, as well as in Febrile infection-related epilepsy syndrome - FIRES) or the so-called destructive encephalopathy of school-aged children (Devastating epileptic encephalopathy in school-aged children - DESC). These facts certainly complicate the classification.

Changes in terminology

According to the ILAE, epileptic encephalopathy is a condition in which epileptiform activity on the EEG contributes to cognitive and behavioral impairment. In this case, a global or selective defect may increase over time. In terms of severity of manifestations, epileptic encephalopathies represent a spectrum of conditions and can be observed in any type of epilepsy and at any age. Syndromes related to epileptic encephalopathies can be either genetic (monogenic cases of West syndrome, Dravet syndrome, etc.) or acquired (for example, the same West syndrome resulting from hypoxic-ischemic encephalopathy of newborns or an infectious lesion in the postnatal period) . Many epileptic encephalopathies are accompanied by “massive” epileptiform activity on the EEG, and a decrease in this activity may lead to improved development of the child.

However, in a number of monogenic epilepsies, developmental regression or developmental “plateau” (a state when new skills are not acquired) in a child may be preceded by both epileptic seizures and epileptiform activity on the EEG. Thus, with Dravet syndrome, in the first two years of a child’s life, there is, as a rule, no “massive” epileptiform activity, and the delay in psychospeech development is already obvious. Therefore, the term “developmental and epileptic encephalopathy” is proposed; thereby emphasizing that the mutation itself (and not just “massive” discharges) leads to intellectual disability and speech disorders. In this regard, it is considered entirely legitimate to use terms without mentioning epilepsy, for example “STXBP1 encephalopathy” or “KCNQ2 encephalopathy”.

The ILAE Terminology and Classification Commission advises avoiding the use of the term “benign” as well as the terms “malignant” and “catastrophic” in relation to epilepsies. It is known that so-called “benign” epilepsies during their active course can cause transient or long-term cognitive deficits (for example, Rolandic epilepsy), and can also be associated with sudden death syndrome in epilepsy.

New classification of types of epileptic seizures

The classification of seizure types is no less important than the classification of epilepsies and also serves to ensure understanding between the different specialists involved in the evaluation and treatment of patients with epilepsy. In addition, the classification allows patients to be grouped by treatment approach, since AEDs are often approved for specific seizure types. Sometimes the type of seizure directly indicates a specific therapy (for example, epileptic spasms in tuberous sclerosis). The classification allows researchers to focus their attention on the mechanisms of development of different types of epileptic seizures and, finally, gives patients terms to describe their illness.

ILAE notes the shortcomings of the classification of seizures (1981) and indicates the following reasons for its revision [8]:

1. Some types of seizures cannot be classified as either focal or generalized (for example, epileptic spasms and tonic seizures are both focal and generalized).

2. Some types of seizures without a clear onset cannot be classified in the 1981 system.

3. It was necessary to move away from assessing the preservation or impairment of consciousness as the only characteristic of a focal seizure, although this is an important classification feature.

4. Some terms are not universally accepted and are not widely used (eg, dyscognitive, psychiatric, partial, simple and complex partial seizures).

5. Some important seizure types were not included in the previous classification.

The previous classification was based on an anatomical principle, distinguishing frontal-lobar, temporo-lobar, parietal-lobar, occipital-lobar, diencephalic and brainstem seizures. Modern studies of the pathophysiological mechanisms of the development of seizures show that epilepsy is a disease of neuronal networks, and not a symptom of local brain damage. From this point of view, an attack can begin both in the neural network of the neocortex and in the thalamocortical or limbic neuronal network. Despite the fairly rapid accumulation of knowledge in this area, our understanding of neural networks still remains incomplete and therefore cannot serve as the basis for a new classification. The creators of the classification sought to make it accessible not only to doctors, but also to patients and their relatives, and also to cover patients of any age, except the neonatal period. At the moment, a special group of specialists has been created who are developing a classification of neonatal epileptic seizures.

An epileptic seizure is the development of transient signs and/or symptoms caused by abnormal excessive or synchronous neuronal activity of the brain [10].

Seizure type—characteristics relevant for interaction in clinical practice, teaching, and research. The mention of seizure type should serve as an indication of a specific unit, sometimes with subgroups and variants. For specific purposes, stakeholders (patients, families, clinicians, researchers, epidemiologists, teachers, insurers, regulators, support groups, and journalists) can include the seizure characteristics they need. For example, a pharmacologist can group attacks by sensitivity to drugs, a surgeon - by anatomy and the possibility of successful surgery, neurophysiologists and neuroresuscitators - by the characteristics of ictal EEG patterns [8].

As noted by R. Fisher et al. [8], at the moment there is not enough data to create a scientific classification, so it is primarily of a practical nature. In summary, the following changes were made to the classification:

1. The term “partial” seizures has been replaced by the term “focal”.

2. To classify focal attacks, the term “awareness” was introduced.

3. Some terms in the description of attacks have been removed - “dyscognitive”, “simple partial”, “complex partial”, “mental” and “secondary generalized”.

4. New focal types of seizures have been introduced - with automatisms, cessation of activity, hyperkinetic, vegetative, cognitive and emotional.

5. It is indicated that atonic, clonic, myoclonic, tonic seizures and epileptic spasms can be both focal and generalized.

6. The term “focal with evolution into bilateral tonic-clonic” replaced the term “secondary generalized” in the description of the attack.

7. New types of generalized seizures have been introduced - absence with eyelid myoclonus, myoclonic absence, myoclonic-atonic seizure and clonic-tonic-clonic seizure.

8. It is stated that seizures of unknown onset may have certain features that help to classify them.

When assessing epileptic seizures, it is first necessary to understand what the initial nature of the manifestations of the attack is - focal or generalized. According to ILAE definition, focal

called an epileptic seizure that develops from the neural networks of one hemisphere.
Generalized
- an attack that develops at some point in the neuronal network of one hemisphere, but with subsequent rapid involvement of bilaterally widespread neuronal networks. Clinicians are well aware that some generalized seizures (eg, absence seizures) are more localized in a specific part of the brain and are essentially bilateral rather than generalized. For some seizures (for example, epileptic spasms), video-EEG monitoring is necessary to determine their type: focal or generalized.

Focal seizures can be associated with a variety of symptoms, features, and behaviors, but ILAE has retained disorders of consciousness as a key feature for grouping focal seizures. Meanwhile, consciousness is a complex phenomenon that includes both subjective and objective aspects. Estimated indicators of consciousness usually include indicators of awareness (awareness, synonym - awareness), response (responses), memory and self-awareness (a sense of oneself as an individual, different from other people). The 1981 classification emphasized awareness and response, but not memory of the event (seizure). Indeed, retrospective assessment of state of consciousness can be difficult. Therefore, in the new classification, awareness is chosen as a relatively simple characteristic of consciousness to assess.

The new classification of attacks includes the following terms: “with intact awareness”, “with impaired awareness”, which means the preservation or disturbance of self-awareness and perception of the external environment during an attack. In this context, awareness characterizes the perception and knowledge of the events that occurred during the attack, and not the knowledge of whether there was an attack or not. But globally this refers to the preservation of consciousness during an attack or its disorder. In practice, the term “intact awareness” means that a patient who has had an attack is subsequently able to recall it and provide a supporting description. However, it should be remembered that in rare cases, attacks can manifest as isolated transient epileptic amnesia with preserved awareness, and the classification of an amnestic attack as focal with impaired awareness requires clear documentation by attentive observers. Awareness may be designated as unclear if its state cannot be specified.

A focal attack may or may not be accompanied by disturbances in response (synonyms - reactivity, ability to respond, maintaining an active state). Responsiveness is not the same as awareness, since in some patients, during an attack, the lack of reactions is due to immobility, but at the same time they are able to perceive and remember what is happening around them. In addition, responsiveness is often not assessed during an attack. For these reasons, responsiveness was not chosen as the primary characteristic for seizure classification. But assessment of the response, if carried out, can serve as a reliable criterion for objectifying the state of consciousness during attacks.

Awareness is not a classification criterion for generalized-onset seizures, since most of them are accompanied by impaired awareness or complete loss of consciousness. It is recognized that awareness and responsiveness may be at least partially preserved during some types of generalized seizures, such as brief absence seizures, including absence seizures with eyelid myoclonus and myoclonic absence seizures.

A focal "conscious" seizure is identical to the former term "simple partial" seizure. The focal "unconscious" seizure is identical to the "complex partial" seizure from the previous classification. There are focal attacks with motor symptoms (motor) and without motor symptoms. Instead of the obsolete, according to the creators of the classification, term “secondary generalized partial” seizure, a new term “focal to bilateral tonic-clonic” seizure is introduced. It is emphasized that the term reflects the fact of the spread of activity, not being any unique type of attack, and is highlighted because it is a common and important symptom. This is followed by a more detailed description of the focal seizure, if possible (Table 1).

Table 1. New classification of types of epileptic seizures [8]

Additional characteristics of focal seizures are too varied to classify and they are not described as separate seizure types [11]. The authors of the classification emphasize the importance of additional characteristics of seizures. Thus, when describing motor attacks, we can say that the attack was hypomotor or Jacksonian, or with a boxer pose. These are important characteristics of the attack, but not the type of attack [11]. The term "aura" has been widely used in the past and may continue to be used, but it is misleading because it is considered the "prelude" of a seizure, when in fact it is a focal epileptic seizure. Therefore, it is proposed not to use this term as a classification term [8].

Generalized seizures are divided into two groups: with motor manifestations (motor) and absence seizures. Further division is similar to the 1981 classification, but with the addition of a myoclonic-atonic seizure (characteristic of myoclonic-astatic epilepsy or Duse syndrome), myoclonic-tonic-clonic seizure characteristic of juvenile myoclonic epilepsy, myoclonic absence seizures (epilepsy with myoclonic absences or Tassinari syndrome ) and absence seizures with myoclonus of the eyelids (Jeevons syndrome). It should be noted that, compared to the previous classification, there is no division of typical absence seizures into simple and complex. The degree of impairment of consciousness (awareness) is not indicated in the name (classification) of generalized seizures, although it is known that it can be partially preserved in short absence seizures and preserved in myoclonic seizures. Generalized seizures may have asymmetric presentation, leading to diagnostic difficulties [8]. It should be noted that, in contrast to juvenile myoclonic epilepsy with myoclonic-tonic-clonic seizures, other idiopathic generalized epilepsies, such as epilepsy with isolated generalized tonic-clonic seizures, as well as juvenile absence epilepsy, are characterized by non-tonic-clonic seizures (the classic term ), namely clonic-tonic-clonic. The primary short clonic phase is usually not noticed, although it is identified by video-EEG monitoring. Bilateral attacks that initially began in the tonic phase are, as a rule, secondary generalized or so-called “pseudogeneralized” in nature.

Noteworthy is the inclusion in both sections (“focal” and “generalized” seizures) of epileptic spasms. This emphasizes the well-known fact that epileptic spasm can be both focal and generalized. In the classification, the spasm is called epileptic, and not infantile, since it has been proven that it can develop at any age, and not just in infancy. Also included in both sections are tonic, clonic, myoclonic and atonic seizures, since according to the mechanism of development they are both focal and generalized.

When using the seizure classification, you can stop at any part of the classification. For example, an attack can be focal or generalized without further specification (when it is not possible to describe the attack in more detail). You can omit the term “without motor manifestations” (“non-motor”) and immediately use the terms “focal sensory”, “focal cognitive”, “focal emotional” and “focal vegetative” attack. An attack with motor manifestations may be described as “focal motor”, “focal tonic” or “generalized tonic” [8, 11].

The term “attack of unknown onset”

(“unknown onset” seizures”). It can occur with or without motor manifestations. As an example, the first tonic-clonic seizure in an adult patient is given (sometimes it occurs in the absence of eyewitnesses). If its focal onset is subsequently clarified, it will be reclassified as “focal to bilateral tonic-clonic seizure”; if its generalized nature is proven, then it will be classified as “generalized.” tonic-clonic."

“unclassified attack” was introduced

- an attack with an unknown onset, unclear symptoms (motor or no motor symptoms) and no data on awareness. If any of the details of the attack are known, then this is mentioned in the description.

The authors of the classification understand that not every epileptic seizure can be classified into a classification, so the group “other type of seizure” can be added to each category.

The International Classification of Diseases, 10th Revision, uses outdated terminology when describing seizures, including the terms “petit mal” and “grand mal.” It is planned that the new International Classification of Diseases, 11th revision, will focus on etiology and syndromes, without touching on the types of epileptic seizures, so the new classification of seizures will not contradict it [8, 11].

The instructions for working with the classification [11] provide a table of correspondence between old and new terms in the description of the types of epileptic seizures. In table 2 shows only the most significant of these correspondences.

Table 2. Correspondence of old and new terms in the description of epileptic seizures [11, modified]

The publication questions the appropriateness of the widely used term “convulsions,” which refer to any motor activity during an attack without clearly describing it. This term is not used in the new classification, but there is an understanding of the fact that it will exist in the public consciousness for a long time.

Thus, the new classification of types of epileptic seizures does not provide for fundamental changes, but, in the authors’ opinion, “has greater flexibility and clarity in determining the types of seizures” [8].

The authors declare no conflict of interest.