MRI findings in the parents and siblings of specifically language-impaired boys.

Four families that include a specifically language-impaired (SLI) boy were studied to test the hypothesis that developmental language disorders are biologically transmittable. A majority of the parents of the SLI boys had experienced communication difficulty (i.e., difficulty with speech, language, or academic skills) as children. Evidence of communication difficulty was paired on an individual basis with neuroanatomical data obtained through quantitative analysis of magnetic resonance imaging scans. Atypical perisylvian asymmetries were documented in a majority of the parents and were frequently associated with a history of communication difficulty. Atypical perisylvian asymmetries and disordered language skills were also documented for siblings of SLI boys. These findings suggest that atypical perisylvian asymmetries reflect a transmittable, biological factor that places some families at risk for language impairment.