Spatial release from speech-on-speech masking in adult hearing aid users

Abstract

Although it is well documented that spatially separating speech maskers from a target speech source normally results in a release from masking, little is known about this effect in hearing aid users. The current study addressed the interaction between spatial release from masking, reverberation, age, and amplification in a multitalker soundfield experiment. The listeners had symmetric sensorineural hearing loss and were experienced users of bilateral hearing aids. The task was to identify the speech of a target talker located directly in front of the listener (0 deg azimuth) in the presence of two masker talkers co-located with the target or spatially separated at ±90 deg azimuth. In this symmetric spatial configuration of sound sources, there was not an overall difference in target-to-masker ratio (T/M) at either ear during stimulus presentation, thus eliminating any ‘‘better ear’’ advantage. Reverberation was varied by physically changing the sound absorption characteristics of the sound booth in which the experiments were conducted. Four listening conditions were tested: unaided, bilateral aided, unilateral aided-right, and unilateral aided-left. In general, the hearing aid users demonstrated less spatial release than normal-hearing listeners although there were large inter-subject differences across the different aided conditions. [Work supported by NIH/NIDCD and AFOSR.]