Abstracts

Rationale: Despite recent advances in the therapeutic options for the treatment of epilepsy, chronic epilepsy still represents 20-30% of the total. Several small studies have looked at different patterns of seizure frequency in chronic epilepsy but little attention has been paid to the impact of aetiology on subsequent seizure patterns Methods: We sought to determine the relative frequency of different seizure patterns in a cohort of patients attending a tertiary referral centre and to determine whether epileptic syndrome or aetiology was predictive of any particular seizure pattern. All participants had by definition chronic active epilepsy. Data was obtained by administration of a patient questionnaire and chart review. Seizure pattern was defined as 1) continuous frequent seizures, 2) intermittent burst pattern 3) infrequent intermittent or 4) continuous frequent seizures of at least five years duration followed by terminal remission. Seizure type and epileptic syndrome were noted in addition to all relevant investigations. Results: To date, 170 suitable patients have been identified. Of these 56% were male with an age range of 16 to 78 years. The majority (61%) had severe epilepsy (defined as a seizure of greater then 1 a month). Patients with partial epilepsy predominated with cryptogenic partial epilepsy being the most common epileptic syndrome. Hippocampal sclerosis (12%) was the most identified lesion. While 64% of patients identified had had continuous seizures since the time of diagnosis, a significant proportion (25%) of those with refractory epilepsy had had at least one period of significant seizure freedom in the past. Conclusions: A higher proportion then expected of those with chronic epilepsy, had a significant period of remission underlying the heterogeneity of seizure patterns in those with chronic epilepsy.