3aPP12. A comparison of the effects of active noise reduction and conventional hearing protectors on auditory perception in normal and hearing-impaired listeners.

Session: Wednesday Morning, May 15

Time: 11:00

Author: Sharon M. Abel
Author: Deborah L. Spencer
Location: Dept. of Otolaryngol., Mount Sinai Hospital, 600 University Ave., Toronto, ON M5G 1X5, Canada


The relative benefit of active noise reduction (ANR), compared with conventional hearing protection, was assessed. Two groups of normal-hearing subjects, differing in age, and one group with bilateral sensorineural hearing loss participated. Subjects were tested with the ears unoccluded, and fitted with E-A-R foam plugs, E-A-R HI-FI plugs, Bilsom Viking muffs, and Peltor 7004 muffs with ANR capability. The E-A-R foam plug provided the highest, and the E-A-R HI-FI plug the lowest, real-world sound attenuation, from 250 Hz to 8 kHz. The Bilsom and Peltor muffs were midway and virtually identical. ANR reduced sound levels by an additional 10 dB at 250 Hz. In normal listeners, protectors improved word recognition in noise but there was no difference due to the device. In impaired listeners, performance in quiet was significantly better with the ears unoccluded or fitted with the E-A-R HI-FI plugs than with the other conventional devices. ANR was midway. In noise, performance was relatively best with ANR and worst with the ears unoccluded. Within group, there were no differences in either duration of frequency difference limens, across conditions. Protected frequency DLs were significantly greater for the impaired group. The results support considering both hearing status and task in assessing hearing protectors. [Work supported by National Defence Canada.]

from ASA 131st Meeting, Indianapolis, May 1996