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THE EFFECTS OF NOISE, AGE, SENSORINEURAL HEARING LOSS AND SPEAKERS UPON WORD RECOGNITION
Abstract
Much is known about the nature and causes of certain types of hearing loss. Although different etiologies of hearing loss may produce similar threshold impairments, as seen on the pure tone audiogram, their effects on the ability to discriminate speech and speakers under less than optimal listening situations are not well defined. It is well established that measures of speech intelligibility obtained in quiet do not provide an accurate assessment of this ability in everyday listening situations. Thus, the purpose of the present investigation was to assess the speech discrimination abilities of normal hearing and hearing impaired listeners in both quiet and noise, in order to study the effects of hearing loss, noise and speakers on speech understanding and speaker intelligibility. Initially, speech discrimination ability was assessed for elderly and young normal hearing individuals in quiet and in noise at comfortable listening levels, using a male and female speaker who were found to produce significant differences in intelligibility in noise in a previous study (Gengel & Kupperman, 1980) of young normal hearing listeners. A significant speaker interaction was found in noise between groups, where the elderly group obtained higher speech discrimination scores with the male speaker and the young, normal hearing group obtained higher scores with the female speaker. The overall performance of the elderly group was significantly poorer than that of the normal hearing group in both quiet and noise. Three additional groups of listeners (acoustic trauma, filtered normal hearing and unfiltered normal hearing) were then assessed and another (female) speaker and softer noise presentation level were included to further investigate speaker and noise interactions. The results obtained indicate that the overall performance of acoustic trauma, filtered normal hearing, and elderly listeners in noise is similar and that the performance of young normal hearing groups in noise is significantly different from these hearing impaired groups. Although differences in group performance scores were apparent, the greater variability of test scores obtained in noise limits the prediction of discrimination ability in noise on the basis of hearing loss. In addition, it was determined that the pure one audiogram did not predict discrimination performance by speaker in noise, although the relationship between performance in noise and high frequency hearing loss was confirmed. Significant speaker interactions were also noted in noise for the three additional subject groups tested. In general, consistent speaker differences were obtained for all groups in noise. The hearing impaired groups obtained higher discrimination scores in noise with the male speaker and the normal hearing groups obtained higher discrimination scores with one of the female speakers. However, the acoustic trauma group did not conform to this general trend of the hearing impaired listeners in the higher noise level condition. The results obtained support the need for the standardization of speaker and conditions for the clinical assessment of speech discrimination performance in noise. Three vocal parameters (intensity, fundamental frequency, and word duration) were assessed for each of the three speakers and correlated with the error scores extracted from 18 of the 50 words presented which produced the greatest dispersion of differences between speakers. Although significant differences were found between speakers for each of the three parameters measured, they were not found to be highly related to the differences in speech intelligibility produced. However, the interactive effects of a speaker's vocal pitch and a listener's hearing loss are postulated. The implications of this investigation and the directions of future research are discussed.
Subject Area
Audiology
Recommended Citation
MARKS, MAURA GREENBERG, "THE EFFECTS OF NOISE, AGE, SENSORINEURAL HEARING LOSS AND SPEAKERS UPON WORD RECOGNITION" (1981). Doctoral Dissertations Available from Proquest. AAI8201358.
https://scholarworks.umass.edu/dissertations/AAI8201358