Continuous spikes and waves during slow sleep: a 30 months follow-up study of neuropsychological recovery and EEG findings.

An eight-year-old boy is reported who presented with a progressive mental deterioration in the years following a nocturnal asymmetrical generalized tonic-clonic seizure. The diagnosis of continuous spikes and waves during slow sleep (CSWS) was made. Once a month a sleep recording was made during twenty-two consecutive months and detailed neuropsychological studies were made over a period of 30 months. Intensive antiepileptic treatment resulted in the disappearance of the CSWS and in a recovery from intellectual-, language- and behavioural disturbances. The good results were still present at a follow-up examination 30 months later.