The Sound Quality Perceived through the Hearing Aid in Relation to the Electroacoustic Characteristics

Abstract

Sound quality perceived through a hearing aid was investigated by factor analysis to find out dimensions in perceived sound quality and to explore their relation to electroacoustic characteristics of the hearing aid.
Sixteen cases with moderate and moderately severe sensorineural hearing losses were studied. They judged quality of test sounds perceived through the hearing aid under 27 different electroacoustic conditions (3 saturation sound pressure levels×3 frequency response characteristics ×3 acoustic gains). The test sounds consisted of various kinds of speech and daily life sounds.
Results were summerized as follows; (1) By means of factor analysis of sound quality, four dimensions were obtained, and the dimensions were interpreted as factors of ‘fullness’, ‘calmness’, ‘distinctness’ and ‘true to nature’; (2) Adjustments of either the SSPL or the acoustic gain had relation with each of four factors; (3) Adjustments of the frequency response related only to the factor of ‘distinctness’; (4) Grade of harmonic distortion, related mainly to the factor of ‘distinctness’.
These results are very useful for fitting hearing aids to cases with sensorineural hearing losses.