Long-term evolution of neuropsychological competences in encephalopathy with status epilepticus during sleep : a variable prognosis

PURPOSE: The aim of this study was to evaluate the long-term cognitive outcome in children with continuous spikes and waves during slow wave sleep (CSWS syndrome). METHODS: We reviewed the neuropsychological tests of 25 children diagnosed with CSWS between 1987 and 2010 and with a mean follow-up of 13.5 years. KEY FINDINGS: Cognitive performances worsened during CSWS in virtually all patients. Seven patients (28%) with nonlesional epilepsy had a positive outcome; three patients (12%) showed persistence of motor deficit without involvement of cognitive functions; and seven patients (28%) who presented a long duration of CSWS (mean = 28.1 months) had a negative cognitive outcome. In 6 patients (24%) with structural or metabolic disorders before CSWS onset cognitive outcomes did not change; 2 patients (8%) had a negative outcome irrespective of the duration or presence of other neurologic disorders before CSWS onset. Forty-four percent of children with CSWS demonstrated permanent cognitive impairment. SIGNIFICANCE: The long-term outcome of CSWS syndrome is variable and seems to depend on treatment response, disease duration, and underlying etiology.