4pPP18. Auditory brain-stem responses in adults with chronic conductive hearing loss.

Session: Thursday Afternoon, May 16

Author: Michael O. Ferguson
Author: Raymond D. Cook
Author: Joseph W. Hall III
Author: John H. Grose
Author: Harold C. Pillsbury
Location: Div. of Otolaryngol., Head and Neck Surgery, Univ. of North Carolina, 610 Burnett-Womack, CB# 7070, Chapel Hill, NC 27599


The ABR is a brief latency, electrophysiologic response that reflects synchronous neuronal activity from the auditory-nerve and brain-stem structures. Investigations have shown that children with early conductive impairment exhibit abnormalities in their ABR, suggesting that the nervous system has an element of plasticity during critical periods of development. However, no similar research has been undertaken on adults to determine whether ABR abnormalities associated with chronic conductive impairment also exist in this population. This study addresses that question by investigating the ABR in a group of adults with chronic conductive loss and a control group of normal-hearing adults. The goal was to determine whether chronic conductive hearing loss in adults would result in similar abnormal ABR measurements as seen in the juvenile population. Subjects were evaluated by comparing ABR interpeak latencies between waves I and III and waves I and V. In addition, interaural latency differences were assessed in cases of unilateral disease. Preliminary results suggest that ABR abnormalities associated with conductive impairment are present. Specifically, in the cases of unilateral disease,there is a significant difference between ears in the waves I--V interpeak latency which is independent of audiometric asymmetry. These data may indicate that an element of plasticity exists in the mature auditory system. [Work supported by NIH NIDCD.]

from ASA 131st Meeting, Indianapolis, May 1996