Epilepsia, 46(12):1937–1942, 2005 Blackwell Publishing, Inc. C  2005 International League Against Epilepsy Levetiracetam Efficacy in Epileptic Syndromes with Continuous Spikes and Waves during Slow Sleep: Experience in 12 Cases Alec Aeby, Nathalie Poznanski, Denis Verheulpen, Catherine Wetzburger, and Patrick Van Bogaert Department of Pediatric Neurology, Erasme Hospital, Universit´ e Libre de Bruxelles (ULB), Brussels, Belgium Summary: Purpose: To assess the add-on efficacy of leve- tiracetam on the EEG, behavior, and cognition of children with continuous spikes and waves during slow sleep (CSWS). Methods: Charts of children with behavioral and/or cogni- tive deterioration associated with CSWS who received levetirac- etam at 50 mg/kg/day as add-on treatment were retrospectively reviewed. Awake and sleep EEG recordings and detailed neu- ropsychological and behavioral assessments were available at baseline and 2 months after levetiracetam initiation. In children showing clinical and/or electrophysiological improvement after 2 months, levetiracetam was continued with a new evaluation at 1 year. Results: Twelve patients were included (9 cryptogenic and 3 symptomatic cases). Seven patients (58.3%) showed improve- ment of EEG record. Among these seven patients, neuropsy- chological evaluation was improved in three, and in the other four patients, not testable because of severe cognitive impair- ment, behavior was improved. Two patients improved in neu- ropsychological evaluation despite the lack of EEG improve- ment. Eight patients (66.6%) continued levetiracetam treatment after 2 months. After 1 year, four patients were still on levetirac- etam, two because sustained effect on EEG and behavior and the two others because improvement in neuropsychological test- ing despite unchanged EEG. Levetiracetam was discontinued in the other four patients because of neuropsychological or behav- ioral deterioration associated with CSWS pattern, between 9 and 11 months after treatment initiation. Conclusions: This retrospective study suggests that levetirac- etam has a positive effect on the EEG, the behavior, and the cognition of patients with epilepsy and CSWS. Additional stud- ies are warranted in order to assess the place of this drug in these epileptic conditions. Key Words: Epilepsy—Drug treatment—Children—Levetiracetam—Continuous spikes and waves—Sleep—Electrical status epilepticus—Cognitive im- pairment. Epileptic syndromes with continuous spikes and waves during slow sleep (CSWS) represent a wide spectrum of epileptic conditions associated with cognitive dysfunction that have the EEG pattern of CSWS as common feature. This spectrum encompasses the Landau–Kleffner syn- drome (LKS) and epileptic syndromes with some kind of neuropsychological deterioration together with strong activation of spike and wave discharges during nonrapid eye movement (NREM) sleep stage (1–8). There is strong evidence, in these epileptic conditions, that cognitive func- tioning may dramatically improve if epileptic activity is reduced with antiepileptic drugs (AED) (1, 9–12). Levetiracetam appears to be a good candidate for phar- macological studies in epilepsies with CSWS. Studies published on the use of levetiracetam in epileptic children have shown an excellent pharmacokinetics and tolerability profile, with little deleterious effects on cognitive function and no known pharmacokinetic interactions. Levetirac- Accepted June 25, 2005. Address correspondence and reprint requests to Dr. Alec Aeby at Pe- diatric Neurology, Erasme Hospital, 808 route de Lennik, 1070 Brussels, Belgium, E-mail: alec.aeby@ulb.ac.be etam has proved his efficacy in partial seizures. Moreover, case series suggest efficacy in some types of generalized seizures (13–18). A decrease of interictal epileptiform dis- charges induced by levetiracetam has been shown in the “genetic absence epilepsy rat of Strasbourg” model (19) and on neocortical slices obtained from patients treated by surgery for refractory epilepsy (20). A positive effect of levetiracetam on interictal epileptiform activity recorded by EEG has been reported in adult epileptic patients (21– 23) and in children with ADHD together with improve- ment of attention (24). Recently, reports have suggested that levetiracetam may be useful in CSWS (25,26). The aim of this study was to assess retrospectively the add-on efficacy of levetiracetam on the EEG, the behavior, and the cognition of a cohort of children with CSWS. PATIENTS AND METHODS In our hospital, patients who are suspected to show the CSWS pattern undergo a systematic comprehensive as- sessment including (1) anamnesis and neurological exam- ination; (2) neuropsychological evaluation adapted to the 1937