Abstracts

The current ILAE epilepsy classification has been criticized because in a general neurology setting, the majority of the patients fall into unspecific categories. Even if a specific syndrome can be diagnosed, important information pertinent to the management of the individual patient (e.g. etiology, seizure types) will not be revealed. We compared the current ILAE epilepsy classification with a 5-dimensional patient-oriented epilepsy classification developed in our institution. This system classifies the epilepsies by specifying the epileptogenic zone, seizure type(s), etiology, severity, and related medical conditions.
Seventy adult and 100 pediatric patients from Cleveland Clinic epilepsy database, and 30 adult patients from the database of an epileptologist working in the Cleveland Metro Health Center were randomly selected. Their charts were reviewed independently by two different investigators and classified according to both the ILAE and the patient-oriented classification. Inter-rater reliability was assessed, and in cases of discrepancies a final consensus among all authors was obtained.
The classification was based on examination by an epileptologist (all patients), routine EEG (80 adults/89 children), cranial MRI (63 adults/75 children), on video-monitoring (21 adults/41 children), and/or epilepsy surgery (4 adults/8 children).
Only 4 adults and 19 children were diagnosed with a specific epilepsy syndrome according to the ILAE classification. All other patients fell into unspecific categories.
The patient-oriented classification showed that 64 adults and 56 children had focal epilepsy. In 34 adults and 45 children, the epileptogenic zone was localized to a focal brain region, or lateralized only (30 adults/ 5 children). The other patients had generalized epilepsy (14 adults/21 children) or it remained unclear if the epilepsy was focal or generalized (16 adults/14 children). 23 adults and 36 children had two or more seizure types. The most frequent seizure type was a generalized simple motor seizure (66 adults/52 children). Etiology was determined in 40 adults and 45 children. Hippocampal sclerosis was the most frequent etiology in adults (10%) and cortical dysplasia (9%) in children. 7 adults and 31 children had at least daily seizures, 17 adults and 26 children had rare or no seizures. The most frequent related medical conditions were psychiatric disorders and mental retardation. Inter-rater agreement was high (kappa-values of 0.8-0.9)
Specific epilepsy syndromes included in the current ILAE classification are rare even in a tertiary epilepsy center. Most patients are included in unspecific categories. In contrast to that, all patients can be classified in the 5-dimensional patient-oriented classification providing all essential information for the management of the patients with a high degree of interrater reliability. Therefore, it seems to be more suitable for clinical use.