Speech perception in noise using directional microphones in open-canal hearing aids.

BACKGROUND: 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.

PURPOSE: 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).

STUDY SAMPLE: 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: 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.

RESULTS: 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.

CONCLUSIONS: These results suggest that directional signal processing should not be precluded in open-canal instruments for listening in noisy environments.