Comparison of Envelope Perception between Syllabic and Dual Compression Hearing Aid Processed Kannada Chimeric Sentences

Abstract

Introduction: Temporal envelope cues and temporal fine structure cues are essential for perception of speech. However, tonal language employ more of TFS cues and non-tonal language employ envelope cues for perception. The native speakers of Kannada use envelope cues for speech perception. Perception might vary depending on the compression characteristics and the number of processing channels in hearing aid users. So, it is important to understand the effect of compression system and processing channels on perception of envelope cues.

Objective: To compare the perception of envelope cues: across different frequency bands; between syllabic and dual compression, between an eight channel and sixteen channel hearing aids, using hearing aid processed Kannada chimeric sentences.

Methods and Materials: Sentence identification task was carried out in thirty native adult Kannada speakers with normal hearing acuity. Stimuli used was hearing aid processed Kannada chimeric sentences prepared with standardised sentence identification test in the Kannada language through Hilbert transformation and processed using 2 hearing aids of eight and sixteen processing channels in syllabic and dual compression programs.

Results: Perception of envelope cues were not significantly different using chimeric sentences processed using syllabic and dual compression system, where as it was significantly different while using chimeric sentence processed using 8 and 16 channel hearing aids.

Conclusion: Dynamic characteristics of compression system such as fast and slow acting have no effect on perception of envelope cues in native Kannada speakers, whereas number of signal processing channels need to be considered while evaluating the perception of envelope cues.