Effect of Number of Channels of Hearing Aids on the Speech Perception in Individuals with Different Degrees of Sloping Hearing Losses

Abstract

Single-channel hearing aids amplify sound alike across all the frequencies whereas Multi-channel hearing aids amplify different frequency components of sound differentially. The reports in the literature are equivocal regarding the effect of increasing the number of channels of hearing aid on speech perception by individuals with hearing impairment. Some studies have found improvement, some worsening and various other studies have shown improvement only up to a limited number of channels. However, these studies have neither specifically targeted the sloping hearing loss population, who are most likely to benefit from increasing number of channels nor have they used high frequency word lists to check for the performance change. So, the present study aimed at determining the effect of number of channels of hearing aids on the speech perception in individuals with different degrees of sloping hearing losses using the conventional as well as high frequency word lists. The participants in the study included 30 post-lingual Kannada speaking individuals with hearing impairment in the age range of 18 to 55 years. They were equally divided into three groups based on the configuration of hearing loss (flat, ski-slope and precipitous slope). The degree of hearing loss was between mild and severe hearing loss. Results revealed increase in the speech perception scores with increase in the number of channels of the hearing aid. The effects were more pronounced for the sloping hearing loss configurations where better results were noticed with 8-channel hearing aid. So, it can be said that individuals with high frequency sloping hearing loss configurations are likely to benefit with multi-channel compression hearing aids, especially with more than 4-channel systems.