Effect of Compression Ratio on Speech Recognition Scores in Subjects with Sensorineural Hearing Loss

Abstract

Compression ratio is the amount of compression provided by the hearing aid once the compression circuit is activated. This study examined the effect of varying compression ratio on speech recognition scores in subjects with sensori-neural hearing loss. Listeners with 1nild-to­ moderately severe sensori-neural hearing loss participated. The test material was phonetically balanced word list in Kannada (Yathiraj & Vijayalakshmi,2005). The speech recognition scores were obtained with PB words in quite condition at 45 dB and 80 dB presentation levels. The compression ratio was varied from 1.0 to 4.0. Results indicated that as compression ratio increased from 1.0 to 4.0 the speech recognition scores are decreased. The speech recognition scores also decreased when speech was presented at higher presentation levels i.e., at 80 dB. These results suggest that high compression ratios and high presentation levels would interact to reduce speech recognition.