The epileptic spectrum in the congenital bilateral perisylvian syndrome. CBPS Multicenter Collaborative Study.

We studied the frequency, clinical and EEG characteristics, and outcome of the epileptic syndrome in 31 patients with a congenital neurologic syndrome characterized by pseudobulbar palsy, cognitive deficits, and bilateral perisylvian polymicrogyria. Seizures were present in 27 of 31 patients (87%) and usually began between the ages of 4 and 12 years; they commonly consisted of atypical absence, atonic/tonic, and generalized tonic-clonic seizures. Partial attacks were present in 26%. EEG demonstrated generalized spike and wave abnormalities and, less frequently, multifocal discharges, predominantly in centro-parietal regions. Seizures were poorly controlled in 65%, with the remaining patients well controlled. Seven patients underwent callosotomy, which resulted in seizure improvement. This study indicates that the epileptic spectrum in this syndrome is broad but follows predictable patterns. Callosotomy is a valuable treatment strategy in those with intractable drop attacks.