Dichotic verbal processing in Down's syndrome children having qualitatively different speech and language skills.

A dichotic word task was used to contrast the speech-perceptual functioning of two groups of Down's syndrome children having qualitatively different speech and language skills to that of nonretarded subjects. Although the 20 nonretarded subjects showed an average 23% right-ear effect on the task, the average ear effect for 29 Down's syndrome subjects was essentially zero. The pattern of phonemic processing of 15 Down's syndrome subjects having better speech and language resembled that of the nonretarded subjects; however, the pattern of 14 Down's syndrome subjects having poorer speech and language was atypical. Place of articulation and voicing of phonemes appeared frequently to have different affects in the latter group in the determination of which dichotic words were reported. Although the group having better speech and language had slightly higher MAs and IQs than the poorer group, MAs and IQs were not related to ear-preference scores.