Effect of Spectral Bandwidth and Spectral Integration on Speech Perception in Listeners with Normal Hearing, Cochlear Hearing Loss and Auditory Dys-Synchrony

Abstract

The present study aimed at finding whether the type of hearing loss has any effect on the bandwidth required to achieve minimum amount of speech identification scores with low and high center frequencies and also ability to integrate information from these two bandwidths. Participants included 29 individuals with normal hearing,12 individuals with cochlear hearing loss and 17 individuals with auditory dys-synchrony. Two CSBs (Criterion Speech bandwidth) were obtained for all the participants. The first one for the low center frequency of 500 Hzand the second one for the higher center frequency of 2500 Hz. To determine the spectral integration abilities,words having both the CSBs were presented to the participants. Results showed that individuals with auditory dys synchrony failed to achieve criterion score even at maximum bandwidth at 500 Hz center frequency. All the three groups differed significantly from each other for the normalized bandwidth required to achieve minimum speech identification scores (normalized CSB) at 2500 Hz. Individuals with auditory dys-synchrony showed significantly lower spectral integration scores from the other two groups and they showed two types of spectral integration scores. One group showed reduced spectral integration scores compared to the criterion score obtained at 2500 Hz center frequency. Another group showed marginal improvement. It was seen that individuals with cochlear hearing loss were as good as normal hearing individuals in their ability to combine the information across different frequency bands.