Abstracts

Rationale: Benign focal epilepsy of childhood with centrotemporal spikes (BECTS) is a common epilepsy syndrome in children. Majority of seizures occur after falling asleep, or just before waking up. Many children will have spontaneous resolution of seizures during the second decade of life, and overall long-term seizure outcome is considered as benign. EEGs in BECTS are characterized by sleep potentiated spikes seen in central and temporal EEG leads, with characteristic morphology, often with a tangential dipole. The natural history and clinical significance of the spikes are not established. When clinical seizures are seen, spikes are very frequent. Spikes may be a biomarker of the clinical course, as spikes may resolve or decrease later in adulthood when seizures resolve. In this study, we quantified the centrotemporal spikes in typical BECTS, and assessed associated factors such as gender, and prophylactic antiepileptic medications.Methods: Over a period of 2 years, retrospectively reviewed patients with BECTS continuously from July 2010 to June 2012, who had EEG studies during awake and sleep. All patients were identified based on clinical seizure semiology and EEG findings with sleep potentiated centrotemporal spikes. Children who had structural brain abnormalities, focal neurological deficits, known other neurological disorders and pre-existing developmental delay were excluded, as such may suggest underlying encephalopathy beyond typical BECTS. EEG was recorded using standard 10-20 international system, and sections with electrode artifact from movement were removed. Recording from the stage I and stage II sleep were extracted for spike quantification. Clinical information was assessed for demographics, and antiepileptic medications at the time the EEG was obtained. When spikes were seen in bilateral hemispheres, spike frequency was assessed for each hemisphere. Results: We reviewed EEGs of 22 patients with BECTS (mean age 9.0 +/-1.8 years), including 13 boys (mean age 9.5 +/- 2.0 years), 9 Girls (mean age 8.4 +/- 1.5 years). 5 had bilateral centrotemporal spikes. 12 were on antiepileptic medications (mean age 9.3+/- 1.5 years), 11 of which were treated with oxcarbazepine alone, and one boy was treated with combination of oxcarbazepine and levetiracetam. Children who were not taking any antiepileptic medication at the time of the EEG, had a mean age of 8.8 +/- 2.2 years. The mean spike frequency in stage I was 22.3 +/- 19.7 spikes /min, and in stage II was 24.7 +/- 15.8 spikes / min, similar between the two stages. When the group was subdivided by gender and treatment with antiepileptic medication, the spike frequency was similar between the two groups (table). Conclusions: In BECTS, children often present with clinical seizures, around 8-9 years of age. At that time, the spikes are seen a frequency of 22-25 / min as above, in stages I and II of sleep. From our study, similar spike frequency is seen in stage I and stage II of sleep, with no obvious difference between genders and treatment with oxcarbazepine. Further larger prospective studies will be necessary to confirm such trend.