Effect of Compression Type and Number of Channels on Speech Perception in Quiet in Listeners with Different Audiogram Configurations

Abstract

Background and Aim: The flexibility to control the gain in different frequency regions by setting compression parameters in a larger number of compression channels in hearing aids will be advantageous to individuals with a sloping audiogram. The objective of the study  was to compare the aided speech identification scores and speech quality ratings in quiet for three aided conditions (i.e. 4-channel, 8-channel, and 16-channel), with syllabic and dual compression, at two input levels (60 dB SPL and 80 dB SPL) in individuals with flat, gently sloping, and steeply sloping sensorineural hearing loss. Methods: The participants were 36 native speakers of Kannada adults with sensorineural hearing loss. In a repeated-measures design, aided speech identification  score for sentences in quiet and speech quality ratings were obtained at two input levels (60 dB SPL and 80 dB SPL) with three hearing aids (having 4-, 8-, & 16- channels), programmed for dual and syllabic compression settings. Results: The results revealed that there was no significant difference in the aided speech identification scores and speech quality ratings, in different aided conditions, in the three groups. Conclusion: There was no additional perceptual benefit in quiet with an increase in the number of channels (from 4 to 16) in hearing aids, either in syllabic or dual compression, at conversation speech level or loud speech level, in individuals with different audiogram configurations. Keywords: Multichannel compression; syllabic compression; dual compression; audiogram configuration; speech identification score; speech quality rating