Effects of Coordinated Compression and Pinna Compensation Features on Horizontal Localization Performance in Hearing Aid Users

Abstract

Hearing-impaired listeners localize sounds better unaided than aided. Wide dynamic range compression circuits operating independently at each ear in bilateral fittings, and microphone positions of different hearing aid styles, have been cited as a reason. Two hearing aid features, inter-ear coordinated compression (IE) and pinna compensation (PC), were developed to mitigate the compromised aided localization performance. This study examined the effect of IE and PC on aided localization performance in the horizontal plane with hearing-impaired listeners. A single-blind, repeated-measures design was used. A total of 10 experienced hearing aid users with bilaterally symmetrical sensorineural hearing loss who had previously participated in localization training were evaluated. Localization performance was measured using 12 loudspeakers spaced 30° apart on the horizontal plane. Aided performance was evaluated using a behind-the-ear hearing aid at four settings: omnidirectional microphone (Omni), Omni microphone with the PC feature, Omni microphone with IE, and Omni microphone with the PC feature and IE together. In addition, unaided localization performance was measured. Significant improvement in the localization accuracy was measured for sounds arriving from the back when comparing the PC with the Omni conditions. The use of IE reduced the magnitude of errors for some listeners for sounds originating from ±90°. The average reduction in the errors was 7.3°. This study confirmed that the use of the PC feature improved localization for sounds arriving from behind the listener. The use of IE may improve localization for some listeners for sounds arriving from the sides.