Effects of Unilateral Hearing Loss on Speech-Evoked Auditory Brainstem Responses and Reading: A Preliminary Study.

PURPOSE
The purpose of this study was to determine whether the speech-evoked auditory brainstem responses (sABRs) obtained by stimulating the ear with normal sensitivity in children with unilateral hearing loss (UHL) were different from that of children with normal hearing (NH), and to explore correlations between the sABR findings and measures of reading.


METHOD
Eleven children with UHL and 11 children with NH were tested via the BioMARK sABR protocol using the syllable /da/; latency and amplitudes of Waves V, A, C, D, E, F, and O were measured. Participants also were tested on the Phonemic Synthesis Test (PST) and the Woodcock Reading Mastery Test-Revised (WRMT-R), particularly the Reading Readiness, Basic Skills, and Comprehension subtests.


RESULTS
Multivariate analysis of variance testing showed a significantly higher amplitude for Wave A for the NH group as compared to the UHL group. Separate ANOVAs also found significantly lower scores for the UHL group compared to the NH group on Basic Skills and Comprehension subtests of the Woodcock. Significant positive Spearman rho correlations were found for the UHL group between wave amplitudes for V, A, and O and the Reading Readiness score, and between wave amplitudes for V, A, D, and O and the Reading Comprehension score. A significant correlation also was found between the Total Reading score and wave amplitudes for V and A. No such correlations were found between wave amplitude and Woodcock scores for the NH group. Further testing of the UHL data found significant relationships between the pure-tone average of the hearing loss ear and the Basic Skills, Comprehension, and Total Reading scores from the WRMT-R. There was also a significant correlation between the PST score and Wave C amplitude.


CONCLUSION
There may be a connection between speech encoding and measures of reading in children with UHL.