Verbal and cognitive sequelae following unilateral lesions acquired in early childhood.

Eight left-hemisphere lesioned children and eight right-hemisphere lesioned children between 18 months and 8 years of age were compared to control subjects on a battery of intelligence and language measures. Both left- and right-lesioned subjects had lower IQ scores than their controls, yet most functioned within the normal range or higher. Lexical comprehension and production were depressed in both subject groups and appeared to be depressed to a greater degree in right-lesioned subjects than in those with left lesions. In contrast, syntactic production in left-lesioned subjects was markedly deficient in comparison to controls as well as right-lesioned subjects. Although both subjects and controls included children with articulation errors, the number of misarticulating children and misarticulated sounds was greatest in the left-lesioned group. Finally, fluency disorders were observed in both right- and left-lesioned subjects but were not observed in controls. The study provides further evidence that the right and left hemispheres are not equipotential for language and that left-hemisphere lesions acquired early in childhood impair syntactic development to a greater degree than do right-hemisphere lesions.