A clinically recognizable neuronal migration disorder: congenital bilateral perisylvian syndrome. Case report with long-term clinical and EEG follow-up.

Congenital bilateral perisylvian syndrome (CBPS) is a recently described, neuronal migration disorder, characterized by pseudobulbar palsy, epilepsy and mental retardation and bilateral perisylvian dysplasia. A 15-year-old boy was diagnosed with CBPS according to the typical clinical, and magnetic resonance imaging (MRI) features. The patient was suffering from atypical absence seizures, repeating daily in spite of antiepileptic drug therapy, since age 7 years. He had also experienced rare generalized tonic-clonic seizures and complex partial seizures. Neurological examination showed severe restriction of tongue movements, severe dysarthria, dysphagia, facial diplegia, mild pyramidal signs and moderate mental retardation. A computed tomographic (CT) scan demonstrated bilateral perisylvian enlargement. The diagnosis was corrected with MRI after six years. Frequent irregular generalized spike and wave abnormalities and focal sharp and slow waves over the posterior regions of both hemispheres were shown by electroencephalograms (EEG). The patient was treated with Na-Valproate, carbamazepine and lamotrigine but did now show any significant change in seizure frequency in the eight-year follow-up period. Intractable seizures, mental retardation and particularly congenital pseudobulbar palsy suggest this congenital entity. Those patients who exhibit these typically clinical features, must have MRI.