Neuropsychological findings in a young adult with congenital bilateral perisylvian syndrome: A case report

Polymicrogyria is a congenital brain malformation characterized by an excessive number of small gyri formed in distinct areas of the cerebral cortex. The perisylvian variant, also known as congenital bilateral perisylvian syndrome (CBPS), is believed to occur in the context of post-migrational trauma during gestational development. Due to the heterogeneity and low prevalence of CBPS, few case studies have characterized its neuropsychological sequelae. We describe an illustrative case study of a 20-year-old young adult male with intellectual and expressive language impairments. Patient's history was notable for significantly delayed developmental milestones such that he was never able to speak beyond single words/syllables. He experienced his first seizure at the age of 6 and, at the time of the evaluation, he was experiencing breakthrough seizures despite being on anti-seizure medication. Given limited expressive language abilities, a bottom-up approach was utilized wherein abilities were assessed iteratively. Data were broadly consistent with moderate-to-severe intellectual disability with deficits in basic and higher-order language globally influencing domains such as spatial attention, working memory and visual learning/recall. He benefited from recognition cues. Motor testing revealed bilaterally impaired strength and fine motor speed/dexterity that were non-lateralized. Collateral report indicated that he required significant support in adaptive functioning and prompting to complete even basic Activities of Daily Living (ADLs). Although fairly brief, this evaluation largely utilized measures that did not require expressive language. This case further highlights the challenges in characterizing cognitive abilities in CBPS patients who fall on the severe end of the spectrum and also have a concomitant history of epilepsy.