International League Against Epilepsy Catagorization
The numerous epileptic seizure types are most commonly defined and grouped according to the scheme proposed by the International League Against Epilepsy (ILAE). Dallas Brain Changers does NOT diagnose Epilepsy and understands this is a complicated and controversial subject.
- Some patients cannot be given a recognized syndromic diagnosis.
- Seizure types and syndromes change as new information is obtained.
- Complete and detailed descriptions of ictal phenomenology are not always necessary.
- Multiple classification schemes can, and should, be designed for specific purposes (e.g. communication and teaching; therapeutic trials; epidemiological investigations; selection of surgical candidates; basic research; genetic characterizations).
This diagnostic scheme is divided into five parts, or Axes, organized to facilitate a logical clinical approach to the development of hypotheses necessary to determine the diagnostic studies and therapeutic strategies to be undertaken in individual patients:
Axis 1: Ictal phenomenology – from the Glossary of Descriptive Ictal Terminology can be used to describe ictal events with any degree of detail needed.
Axis 2: Seizure type – from the List of Epileptic Seizures. Localization within the brain and precipitating stimuli for reflex seizures should be specified when appropriate.
Axis 3: Syndrome – from the List of Epilepsy Syndromes, with the understanding that a syndromic diagnosis may not always be possible.
Axis 4: Etiology – from a Classification of Diseases Frequently Associated with Epileptic Seizures or epilepsy syndromes when possible, genetic defects, or specific pathological substrates for symptomatic focal epilepsies.
Axis 5: Impairment – this optional, but often useful, additional diagnostic parameter can be derived from an impairment classification adapted from the WHO ICIDH-2.
Definitions of Key Terms
Epileptic Seizure Type: An ictal event believed to represent a unique pathophysiological mechanism and anatomical substrate. This is a diagnostic entity with etiological, therapeutic, and prognostic implications. (new concept)
Epilepsy Syndrome: A complex of signs and symptoms that define a unique epilepsy condition with different etiologies. This must involve more than just the seizure type; thus frontal lobe seizures per se, for instance, do not constitute a syndrome. (changed concept)
Epilepsy Disease: A pathological condition with a single specific, well-defined etiology. Thus Progressive myoclonus epilepsy is a syndrome, but Unverricht-Lundborg is a disease. (new concept)
Epileptic encephalopathy: A condition in which the epileptiform abnormalities themselves are believed to contribute to the progressive disturbance in cerebral function. (new concept)
Benign epilepsy syndrome: A syndrome characterized by epileptic seizures that are easily treated, or require no treatment, and remit without sequelae. (clarified concept)
Reflex epilepsy syndrome: A syndrome in which all epileptic seizures are precipitated by sensory stimuli. Reflex seizures that occur in focal and generalized epilepsy syndromes that are also associated with spontaneous seizures, are listed as seizure types. Isolated reflex seizures can also occur in situations that do not necessarily require diagnosis of epilepsy. Seizures precipitated by other special circumstances, such as fever or alcohol withdrawal, are not reflex seizures. (changed concept)
Focal seizures and syndromes: Replaces the terms partial seizures and localization-related syndromes. (changed concept)
Simple and complex partial epileptic seizures: These terms are no longer recommended, nor will they be replaced. Ictal impairment of consciousness will be described when appropriate for the individual seizures, but will not be used to classify specific seizure types. (new concept)
Idiopathic epilepsy syndrome: A syndrome that is only epilepsy, with no underlying structural brain lesion or other neurological signs or symptoms. These are presumed to be genetic and are usually age-dependent. (unchanged term)
Symptomatic epilepsy syndrome: A syndrome in which the epileptic seizures are the result of one or more identifiable structural lesions of the brain. (unchanged term)
Probably symptomatic epilepsy syndrome: Synonymous with, but preferred to, the term cryptogenic, used to define syndromes that are believed to be symptomatic, but no etiology has been identified. (new term)