A functional magnetic resonance Imaging study of left hemisphere language dominance in children

Background: Functional magnetic resonance imaging is a noninvasive method of assessing language dominance in a pediatric population. Objective: To determine the pattern of receptive language lateralization in healthy children. Design: We used functional magnetic resonance imaging to assess an auditory language task in 11 children (7 girls, 4 boys; mean age, 8.5 years). Participants alternately rested and listened to descriptors of nouns presented auditorily, naming the object described silently. Asymmetry indices ([left - right)/(left + right)]) were calculated for a priori-determined regions of interest. Results: The results showed strong activation bilaterally, with greater activation on the left in the superior and middle temporal gyri. Other areas of activation included the cuneus, the left inferior temporal gyrus, the prefrontal area, and the left fusiform and lingual gyri. Regions of interest analysis of individual scans showed additional activation in the left frontal lobe. Asymmetry indices showed strong left lateralization of the inferior frontal gyrus, middle frontal gyrus, and the Wernicke region. Conclusions: Hemispheric lateralization was clearly demonstrated in 8 children. As in adults, left hemisphere lateralization of receptive language is present at age 8 years.