Abstracts

Rationale: Benign focal epileptiform discharges (BFEDs) with sleep-activated diphasic, high-voltage, typically centro-temporal spikes are present on EEG in 1-2% of healthy children. BFEDs may present in the setting of benign epilepsy with centro-temporal spikes (BECTS) or as an independent EEG feature. The EEG frequently normalizes by adolescence and seizures in BECTS stop, but the specific evolution over time is unknown. Methods: All pediatric routine EEGs from 1995-2004 were reviewed for BFEDs and charts of patients with BFEDs were reviewed for patient demographics, repeat EEGs, and clinical seizure presentation. BECTS was defined as (a) seizures consisting of typical brief hemifacial seizures associated with speech arrest, drooling, and preservation of consciousness or with gurgling/grunting noises with loss of consciousness and terminating in vomiting or (b) nocturnal secondarily generalized seizures. Descriptive data and Fisher’s exact test was used for analysis. Results: BFEDs were found on EEGs in 213 children. Ninety-nine charts were available for review of which 54 patients had BECTS. Two patients had concurrent focal spike and waves, while another patient had concurrent generalized spike and waves. Mean age of clinical seizure onset was 6.8 years in BECTS patients (range 1.8-11.5 years) with the mean age of the first EEG with BFEDs being 7.8 years (range 3-11 years). The mean age of first EEG with BFEDs in the BFED-only group was 8.5 years (p=0.044). Forty-one children with BECTS (75.9%) had more than one clinical seizure. Mean length of clinical seizures was 1.8 years (range 0-8 years) with mean age of seizure cessation being 8.6 years (range 3.2-16.0 years). Repeat EEGs were done in 30 patients (55.6%) with a mean of 2.4 EEGs done per child. The mean length of time between first and last EEG was 51.7 months (range 1-107 months). Eleven patients had repeat EEGs (36.7%) that were normal. Two other patients had EEGs that evolved into focal spike and waves (one of which initially normalized), while another patient had an EEG that evolved into generalized spike and waves (EEG initially normalized as well). Of the patients with other concurrent epileptiform discharges, two patients had follow-up EEGs that normalized. The other patient did not have a follow-up EEG. The mean age at which the first EEG showed no BFEDs was 12.1 years (range 8-16 years) in children with BECTS versus 12.6 years in children with BFEDs only (p=0.058). Mean length of clinical follow-up was 33.5 months (range 0-142 months) with 14 children (25.9%) having no follow-up. Conclusions: Although follow-up EEGs were performed inconsistently in this retrospective study, BFEDs disappeared in more than 1/3 of our BECTS patients, over an average time of 4.3 years. More than half also had BECTS (most having more than one seizure) lasting almost 2 years on average. On average, BFEDs appeared at 8 years and disappeared at 12 years irrespective of the presence or absence of seizures or other concurrent epileptiform discharges. A better understanding of the natural course of BFEDs and BECTS may be helpful for improved management.