Abstracts

Rationale: Patients with Continuous Spikes and Waves during Sleep (CSWS) respond to high-dose diazepam therapy but there is limited data on response to other benzodiazepines. The aim of this study is to test whether high-dose clobazam treatment leads to improvement in patients with CSWS.Methods: We retrospectively evaluated patients with CSWS before and after treatment with high-dose clobazam at two tertiary pediatric hospitals. We included patients 2-21 years admitted to long-term EEG (>18 hours) monitoring unit for clinical suspicion of cognitive regression together with frequent discharges on EEG (at least 50% spike percentage during slow wave sleep) and treated with high-dose clobazam (1 mg/kg before sleep and subsequently 0.5 mg/kg nightly). Patients continued treatment for three months. Immediately before treatment and 3 months after treatment we evaluated seizure frequency as well as interictal epileptiform activity during non-REM sleep using spike percentage (percentage of one second bins with at least one spike wave in it) and spike frequency (total number of spike waves/100 sec). Results: Seven patients (4 males) with a median (p25-p75) age of 7.8 (6.9-9.7) years were included. Spike percentage improved from a median (p25-p75) of 84 (55-95) at baseline to 63 (42-90) 3 months after treatment. Spike frequency improved from a median (p25-p75) of 138 (60-155) at baseline to 80 (60-177.5) 3 months after treatment. Seizure frequency decreased from a median (p25-p75) of 0 (0-12) at baseline to 0 (0-0) 3 months after treatment. According to parent report, three patients showed some behavioral improvements at three-month follow-up. Three patients had mild drowsiness during high-dose clobazam treatment. One additional patient discontinued clobazam due to agitation one day after initiation and was not included in our analyses.Conclusions: We found a reduction of seizure frequency and improvement of epileptiform activity in patients with CSWS treated with high-dose clobazam. Ongoing data collection and correlation with neuropsychological outcome will assist in determining the consistency of these findings in other patients with CSWS.