Dichotic ear advantages in adults with Down's syndrome predict speech production errors.

Intellectually challenged adults, with and without Down's syndrome (DS), pointed to drawings of animals following the dichotic presentation of animal names. Although there were no reliable ear differences between the 2 groups, there was tremendous between-persons variability within the group of participants with DS. Moreover, left-ear advantages in persons with DS were associated with more speech production errors when participants either read or repeated a string of 1 syllable words. This was not true for control participants. The relationship between ear advantage and speech errors in persons with DS could reflect their unique pattern of cerebral specialization and brain development.