Congenital perisylvian dysfunction – is it a spectrum?

Aim  This study examines the overlap between children with bulbar cerebral palsy (Worster–Drought syndrome [WDS]) and perisylvian polymicrogyria. Method  A total of 121 children (81 males, 40 females; mean age 5y 5mo, SD 3y 6mo; age range 1mo–15y 4mo) were studied using retrospective clinical data and magnetic resonance imaging. In all, 70 children had WDS with normal perisylvian imaging, 31 had congenital bilateral perisylvian polymicrogyria (CBPP), and 20 had congenital unilateral perisylvian polymicrogyria (CUPP). Results  All groups shared aetiological markers (male sex, congenital contractures, low familial incidence, excess antenatal events). There was a common phenotype of pseudobulbar palsy with mild limb pyramidal signs in all children with WDS, 90% of those with CBPP, and one-third of those with CUPP, often also associated with learning disability*, epilepsy, and behavioural difficulties. A further 15% of children with CUPP acquired this phenotype through an epileptic encephalopathy. Pseudobulbar palsy rather than polymicrogyria was more predictive of additional impairments other than epilepsy. Interpretation  We propose that congenital perisylvian dysfunction is a spectrum encompassing the WDS phenotype and perisylvian polymicrogyria imaging abnormalities. As with other prenatal brain abnormalities, there is not necessarily concordance between imaging and clinical findings, although the phenotype is often more severe to manifest imaging abnormality. Clinical phenotype is the best indicator of prognosis. Epileptic encephalopathy can cause an acquired form of perisylvian dysfunction where there is.