THE EFFECT OF LOW FREQUENCY HEARING AID RESPONSE ON FOUR MEASURES OF SPEECH PERCEPTION
Abstract
The relationship between low frequency amplification, listener preferences and speech intelligibility was investigated. Subjects were six individuals with mild to moderate sensorineural hearing loss. They used magnitude estimation procedures to make judgments of the quality and intelligibility of a speech passage while listening through three different hearing aids. The Speech Perception in Noise test and the California Consonant Test were also administered while the subjects wore the same three hearing aids. Electroacoustic measures demonstrated the hearing aids to be essentially identical except for low frequency response. All tasks were completed at three sound pressure levels, 90 dB, 100 dB and 110 dB SPL, measured in the subjects' ear canals. Results indicated that both quality judgment and intelligibility judgment procedures were reliable and that they were effective in differentiating among the three hearing aids. A strong correlation was found between the two procedures. Listener hearing aid preferences were related to presentation level and degree of low frequency hearing loss. They did not exhibit a general preference for a single hearing aid. The SPIN test and the CCT did not consistently differentiate among the hearing aids. The correlation between these tests was relatively weak. The SPIN test results were largely unaffected by presentation level, but the CCT evidenced a strong level dependence. The results offered no indication that listeners preferred hearing aid characteristics which degraded speech intelligibility. It was concluded that either quality or intelligibility judgments constitute an effective and valid means of differentating low frequency hearing aid response.
Degree
Ph.D.
Subject Area
Audiology
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