Cerebral configurations among the parents and siblings of language-disordered boys.

Abstract

Four families that include a specifically language-impaired (SLI) boy served as subjects of this study. The background and behavioral characteristics of these subjects indicated that a majority of the parents and siblings of the language-disordered boys also experienced difficulty with speech, language, and academic skills. This information was paired with neuroanatomical data obtained through quantitative analysis of magnetic resonance imaging (MRI) scans. Atypical perisylvian asymmetries, a characteristic previously associated with developmental language disorders in children, were documented in the majority of the parents of language-disordered boys (p < .05). Atypical perisylvian asymmetries in these parents were closely associated (p = .84) with a positive history for difficulty with speech, language, or academic skills. The presence of these behavioral and biological characteristics in the parents of SLI boys is consistent with the hypothesis that language disorders are biologically transmittable. Siblings in one of the four families had documented impairments of language skills. These subjects also had atypical perisylvian asymmetries. An additional sibling from a second family had atypical perisylvian asymmetries. The presence of atypical perisylvian asymmetries in multiple family members suggests that atypical perisylvian asymmetries reflect biological factors that place some families at risk for language impairment. The pattern of atypical perisylvian asymmetries documented in this study reflect a probable disturbance of prenatal brain development. Measurement of cerebral areas in addition to the perisylvian demonstrated that the hypothesized effects on the developing brain were bilateral and widespread. These features are in contrast to the neuroanatomical profile typically associated with cases of acquired language disorder, which typically result from damage to the left perisylvian area in a premorbidly normal brain.