Cued dichotic listening with right-handed, left-handed, bilingual and learning-disabled children

This study used cued dichotic listening to investigate differences in language lateralization among right-handed (control), left-handed, bilingual, and learning-disabled children. A sample of 60 subjects ranging in age from 7-13 yr were administered a CVC dichotic paradigm with three experimental conditions (free recall, directed left, directed right). A three-factor ANOVA design conducted on the data revealed that control, bilingual, and learning-disabled children produced the expected REA suggestive of left hemisphere dominance for language processing whereas left-handed children produced an LEA suggestive of right hemisphere superiority for language processing. The cued attention data derived from groups as well as from individual subjects suggested that in comparison with control children, left-handed children were greatly susceptible to attentional manipulation similar to learning-disabled children only in the opposite hemisphere. Bilingual children were found to have a REA much like control children although recall accuracy was depressed. Further, lambda (lambda) analyses conducted on individual subjects indicated that the magnitude and degree of perceptual asymmetry varied widely among individuals of various anomaly groups. These findings lend support to the hypothesis that attentional factors play a larger role in unilateral processing for some anomalous groups of children (i.e. left-handers and learning-disabled) while not affecting others (i.e. controls and bilinguals).