Cognitive functioning in bilateral perisylvian polymicrogyria (BPP): clinical and radiological correlations

Introduction. Bilateral perisylvian polymicrogyria (BPP) is a malformation of cortical development, frequently associated with severe dysarthria or anarthria. BPP patients are therefore often labelled as severely retarded, but a detailed neuropsychological
profile has not been reported to date.
Aim. To determine relation of BPP with exceptionally low inteligence if any and correlation between the extent of the cortical desorganization abd documented cognitive deficits.
Material and method. Material included 14 adult patients with bilateral perisylvian polymicrogyria. Clinical, neuroradiological and neuropsychological data was evaluated. Correlations between degree of cortical desorganization based on radiological scale and cognitive functioning were analysed.
Results. Among 14 patients only 4 was mentally retarded, all of them severely. Early age at seizure onset correlated positively with Performance IQ scores (p < 0,05) and negatively with the extent of the lesion (p < 0,01). Receptive and expressive language skills were found to be equally poor. Frontal lobe function and memory abilities were relatively well preserved.
Conclusions. In patients with bilateral perisylvian polimicrogyria some aspects of cognitive function correllated with the extent of the cortical desorganization. Only a minority of patients had extremely low intelligence.