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Degree

Doctor of Philosophy, Ohio State University, Speech and Hearing Science, 2002.

Abstract

Occupational hearing conservation regulations neither address issues related to speech intelligibility in noise for normal-hearing or hearing-impaired workers, nor do the regulations comment on the safety of hearing aid use by hearing-impaired workers. Do certain types of hearing protection devices (HPDs) allow for better speech intelligibility than others? Would use of hearing aids with earmuffs provide better speech intelligibility for hearing-impaired workers? Is this method of accommodation safe? To answer these questions, a method for evaluating speech intelligibility with HPDs was developed through a series of pilot tests. The test method allows for evaluation of both normal-hearing and hearing-impaired listeners. Speech intelligibility for normal-hearing listeners who wore uniformly attenuating earmuffs was found to be significantly better than for the same listeners who wore conventional earmuffs. Hearing-impaired listeners were tested with each type of earmuff and while wearing their own hearing aids in combination with each earmuff. Unlike the normal hearing listener group, the hearing-impaired listener group did not exhibit better speech intelligibility with the uniformly attenuating earmuffs than with the conventional earmuffs. However, earmuffs worn in combination with hearing aids allowed for significantly better speech intelligibility than with either earmuff alone. To determine the safety of hearing aid use under earmuffs, a model was developed to predict occupational noise exposure for the aided-protected worker. Data from real ear measures with an acoustic mannequin was found to be in agreement with model predictions.

Keywords

hearing conservation; hearing aids; earmuffs; speech intelligibility in noise

Advisor

Lawrence L. Feth

Pages

179p.

Document number: osu1038964671
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=osu1038964671

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