Rett syndrome associated with continuous spikes and waves during sleep.

Major speech impairment is a cardinal feature of Rett syndrome. Epilepsy, of variable presentation, is also frequently described. We report a girl who presented rapid speech regression while EEG showed continuous spikes and waves during slow sleep. The clinical picture was consistent with Rett syndrome, confirmed by MECP2 mutation R133C. We hypothesized that speech regression was partially related to nocturnal epileptic activity. Several antiepileptic drugs were used unsuccessfully but valproic acid was accompanied by improvement of verbal fluency, social interaction and manual abilities as measured by the Quebec Scale of Adaptive Behaviors and the Rett syndrome adapted Kerr scale. Continuous spikes and waves during slow sleep are unexpected in the early stages of Rett syndrome. This report suggests that it might contribute to the clinical impairment, in particular communicative capabilities, and that adequate antiepileptic treatment may be beneficial.