Speech Perception in Noise Using Directional Microphones in Open-Canal Hearing Aids

Abstract

Individuals with impaired hearing find it difficult to understand speech in the presence of background noise--a problem addressed effectively by directional microphones. As open-canal fittings have become increasingly popular in the recent past, so has the debate about the effective directional benefit available from these devices. This study investigates the benefit of directional microphones in two commercially available open-canal behind-the-ear hearing aids using the Hearing in Noise Test (HINT). Sixteen individuals, between 50 and 85 year of age, with high-frequency bilateral sensorineural hearing loss and no previous hearing aid experience participated in this study. Data Collection and Analysis: Individuals were asked to repeat sentences (presented at 0 degrees azimuth) in the presence of a diffuse-field uncorrelated broadband speech-shaped noise. HINT performance was compared across hearing instruments and conditions using a linear model with repeated measures. There was a directional advantage of 2.6 dB as compared to the unaided condition. Average performance was worse in the omnidirectional mode as compared to the unaided condition. These results suggest that directional signal processing should not be precluded in open-canal instruments for listening in noisy environments.