Effect of Envelope Enhancement on Speech Reception and Late Latency Response Measures in Subjects with Auditory Dys-Synchrony

Abstract

Auditory neuropathy is a disorder characterized y the impairment of the peripheral auditory function with the preservation of OHCs (Starr, et al. 1996; Berlin et al., 1998 ;) It is known fact that these individuals have problem with speech discrimination. Aim: To compare the effect of envelope enhancement on speech perception and LLR in subjects with auditory neuropathy, with those associated with normal hearing. Method: 11 VCV syllables were recorded using an adult male voice by using PRAAT software. These syllables were further mixed up in preset proportion of speech noise to make it in 10 dB SNR condition. In perceptual testing the subjects task was to repeat the stimuli is heard, in both for quiet as well as 10 dB SNR condition for non enhanced and enhanced stimuli, whereas objective recording was done using only one stimulus /da/, where latency, amplitude and morphology of LLR were recorded in quiet condition fr non enhanced and enhanced stimulus. The testing was done for AN/AD subjects as well as age and gender matched subjects with normal hearing. Results: analysis was done using SPSS version 15, which revealed that there is decease in latency and better amplitude in both groups with enhancement, but it was not significant for all the peaks. Mean and standard deviation are given for each analysis. Conclusions : The envelope enhancement did tend to decrease the latency and increase the amplitude of LLR, but the effect was not much significant for all the peaks, hence more advanced study with better control over the variables is advocated.