Speech processing for hearing aids for moderate bilateral sensorineural hearing loss

Abstract

Binaural dichotic presentation can be used for reducing the effects of increased temporal and spectral masking associated with sensorineural loss and for improving speech perception by persons with moderate bilateral loss. Speech processing schemes based on adjustable gain filtering, spectral splitting with perceptually balanced comb filters, temporal splitting with trapezoidal fading and inter-aural switching period of 20 and 40 ms, and combined splitting with cyclically swept comb filters with cycle time of 20, 40, and 80 ms were implemented. Experimental evaluation was carried out through listening tests involving recognition of randomly presented words by hearing impaired subjects, for establishing the effect of processing schemes and parameters. Binaural filtering always resulted in improvement. Maximum number of subjects showed large improvement with spectral splitting. Temporal splitting was better with 20 ms switching, while the combined splitting gave best improvements for cycle time of 40 ms.

Reverberation canceling wireless aid for hearing impaired

“…[5]. Since the requirements on the hearing aid vary patient to patient, there are several issues which need further attentions in order to provide better quality from user point of view, such as:…”

Multi-band frequency compression for reducing the effects of spectral masking

“…Several studies have been reported on binaural dichotic presentation, using a pair of comb filters with complementary magnitude responses for spectral splitting, to reduce the effects of spectral masking for persons with moderate bilateral sensorineural hearing impairment (Lyregaard 1982;Lunner et al 1993;Chaudhari and Pandey 1998;Cheeran and Pandey 2004;Kulkarni et al 2006). For monaural hearing, effect of increased spectral masking may be reduced by multi-band frequency compression.…”