Dichotic consonant-vowel (CV) perception in normal and learning-impaired children

Two experiments were performed using dichotic presentation of the consonant-vowel (CV) syllables [pa], [ba], [ta], [da], [ka], and [ga]. The stimuli were constructed with no temporal offsets between channels (+/-2 msec) and with temporal offsets of 30, 60, and 90 msec between channels. Data were analyzed for ear asymmetry (right ear advantage), double-correct responses (auditory capacity), and the effects of temporal offsets (the lag effect). In experiment 1, 32 normal children (mean age at entry = 6 yrs 6 mos) were evaluated once each year over a 4-yr period. Results showed no significant change in ear laterality over the 4 yrs. However, there was a significant, age-related increase in auditory capacity. None of the subject groups showed a significant lag effect. In experiment 2 results from 17 children (mean age = 9.3 yrs) enrolled in a school for learning disability who were identified as having significant auditory processing problems were compared to age- and sex-matched normal controls. Results failed to show a significant group difference for ear asymmetry, auditory capacity, or the lag effect. Case studies are presented comparing two learning-disabled children with two normal children matched for age and sex to illustrate the results for the learning-impaired population. Overall, findings indicate that the dichotic CV syllables test has limited prognostic value in identifying auditory processing dysfunction in children classified as having "learning disability."