Specific language impairment: linguistic and neurobiological aspects.

Specific language impairment (SLI) occurs when children present language maturation, at least 12 months behind their chronological age in the absence of sensory or intellectual deficits, pervasive developmental disorders, evident cerebral damage, and adequate social and emotional conditions. The aim of this study was to classify a group of children according to the subtypes of SLI and to correlate clinical manifestations with cortical abnormalities. Seventeen children with SLI were evaluated. Language assessment was based on standardized test (Peabody) and a non-standardized protocol, which included phonological, syntactical, semantical, pragmatical and lexical aspects of language. All children, except one, had abnormal MRI. Thirteen children presented perisylvian polymicrogyria. The MRI findings in the remaining three patients were: right frontal polymicrogyria, bilateral fronto-parietal atrophy, and hypogenesis of corpus callosum with Chiari I. The data show that patients with posterior cortical involvement tended to present milder form of SLI (no sign of articulatory or bucofacial praxis disturbance), while diffuse polymicrogyric perisylvian cortex usually was seen in patients who presented severe clinical manifestation, mainly phonological-syntactic deficit. In conclusion, SLI may be associated with perisylvian polymicrogyria and clinical manifestation may vary according to the extent of cortical anomaly.