The congenital bilateral perisylvian syndrome: imaging findings in a multicenter study. CBPS Study Group.

Objective: To describe the neuroimaging findings and the clinical features in patients with the congenital bilateral perisylvian syndrome.

Methods: Evaluation including history, general and neurologic examinations, electroencephalogram, chromosomal studies, and imaging data were reviewed in 31 patients. Pathologic material was available in two patients.

Results: All patients had similar neurologic dysfunction, primarily pseudobulbar paresis. Dysarthria and severe restriction of tongue movements were present in all. Motor milestones were delayed in 75% of the patients and language milestones in all. Mild to moderate intellectual deficits were documented in 75% of patients (full-scale IQ = 70). Pyramidal signs were observed in 70%. Seizures were present in 87% and were intractable to medical therapy in half of this group. MR revealed bilateral perisylvian and perirolandic malformations with exposure of the insula. The malformations were symmetrical in 80% of cases. Pathologic correlation revealed four layered polymicrogyria in the affected areas.

Conclusions: The congenital bilateral perisylvian syndrome is a homogeneous clinical-radiologic entity. The underlying abnormality is probably polymicrogyria.