4aEA8. Evaluation of the perception of input-referred noise in hearing aids.

Session: Thursday Morning, December 5

Time: 10:00

Author: Lidia W. Lee
Location: Dept. of Communicative Disord., Northern Illinois Univ., DeKalb, IL 60115
Author: Earl R. Geddes
Location: Knowles Electronics, Inc., Itasca, IL 60413


Hearing-aid circuitry noise has been a major complaint among hearing-aid users, especially among those who have normal hearing at low-frequencies. The purpose of this study is to examine the spectral distribution of the noise-tolerance range for hearing-impaired listeners. The primary purpose of this study is to determine the upper and lower fences of the permissible equivalent input noise (in dB SPL) of a hearing aid. First the audiometric threshold is evaluated, then the just-audible noise level (JAL) and the just-objectionable noise levels (JOL), measured in dB SPL at the eardrum, are determined in quiet using normal hearing and hearing impaired listeners. Given the audiometric threshold, various prescriptions can then be applied to obtain the target gain values. The JOL minus the prescribed gain values (Rx) and the JAL minus Rx represent the maximum input noise level an individual will tolerate and the just-noticeable input noise level, respectively. These data will be useful as specifications of input referred noise for hearing-aid components. The mean and standard deviation of input referred JOL and JAL, in one-third octave bands, for normal-hearing and hearing-impaired listeners will be reported. [Work supported by Knowles Electronics, Inc.]

ASA 132nd meeting - Hawaii, December 1996