Background: Subtle disorders of neuronal migration occur in the brains of some dyslexic patients who presented developmental language disorder (DLD) during early childhood.

Objective: To investigate a possible neuroanatomical substrate based on neuroimaging evaluation in children with DLD.

Methods: The authors obtained psychological assessment, language evaluation, neurologic examination, and neuroimaging investigation. Inclusion criteria were as follows: children should be at least 4 years of age; primary complaint of language delay; normal hearing; IQ >70; and an informed consent form signed by parents or guardians. Exclusion criteria were severe motor and cognitive handicap.

Results: Fifteen children met all inclusion criteria. Ages ranged from 4 to 14 years and 11 were boys. Six patients presented diffuse polymicrogyria (PMG) around the entire extent of the sylvian fissure on MRI, and they had severe clinical manifestation of DLD: they did not speak at all or had mixed phonologic-syntactic deficit syndrome. Six children presented PMG restricted to the posterior aspects of the parietal regions, and they had a milder form of DLD: mainly phonologic programming deficit syndrome. The other three children had different imaging findings.

Conclusions: Developmental language disorder can be associated with polymicrogyria and the clinical manifestation varies according to the extension of cortical abnormality. A subtle form of posterior parietal polymicrogyria presenting as developmental language disorder is a mild form of perisylvian syndrome.