Effect of Hearing Aid Channels on Acoustic Change Complex

Abstract

The objective of the present study was to find the effect of varying the number of channels of a hearing aid on the Acoustic change complex (ACC) in individuals with sloping hearing loss and to verify the same using the speech identification scores. The ACC was obtained from individuals with normal hearing and those with sloping sensorineural hearing loss in response to /si/ stimulus, the comparison in ACC wave forms were then made betweenthese two groups. The ACC obtained across two. four and eight channel hearing aids with the same make and manufacturer were compared. A high frequency content speech identification test was done as a behavioral correlation measure. The results showed that ACC latencies in response to the fricative portion Isl were delayed in individuals with sloping hearing loss. Between the two, four and eight channels, there were no significant differences found in terms of latency, amplitude, morphology or speech identification scores. The electro physiological findings were found to poorly correlate with the behavioral speech identification measure. Therefore it was concluded that naturally produced speech tokens, representing different acoustic cues, like frication and vowel steady states can evoke distinct neural response patterns, and cortical evoked potentials elicited by /si/ stimulus can be reliably recorded in individuals with and without hearing aids. There was no significant difference in perception found between the two, four and eight channels.