Effect of Different Compression Procedures on Aided Speech Identification Scores in Individuals with Varying Degrees of Hearing Loss

Abstract

The aim of the present study was to·determine the effect of different .types of compression on aided speech identification scores (ASJS) in a group of individuals with hearing impairment of varying degrees. The ASIS were determined at two presentation levels (40 and 70 dB HL) in a quiet environment, for three types of compression ( i.e., Dual compression only, Syllabic compression only and a combination of both Dual and Syllabic compression across thefrequency channels). Ten ears in ·each degree of hearing loss (Moderate, Moderately Severe, and Se.vere), a total of 30 ears, were taken in the present study. ASIS were determined by using phonemically balanced word list developed by Yathiraj and Vijayalakshmi (2005). The results of the present study indicated that there was a significant improvement in ASIS for the compression procedure in which a combination of the two procedures was used. However, there was no significant difference when any one of the compression procedures was used individually in all thefrequency channels across various degrees of hearing loss. This indicates that the consonant to vowel ratio is more enhanced in the combined compression procedure than when only one of the compression procedures is used. There was also a significant improvement for a higher presentation level when compared to a lower presentation level irrespective of the compression procedure used. This could be attributed to the better audibility of the speech.