Hearing-in-Noise: Comparison of Listeners with Normal and (Aided) Impaired Hearing

Abstract

In this study, the performance of 48 listeners with normal hearing was compared to the performance of 46 listeners with documented hearing loss. Various conditions of directional and omnidirectional hearing aid use were studied. The results indicated that when the noise around a listener was stationary, a first- or second-order directional microphone allowed a group of hearing-impaired listeners with mild-to-moderate, bilateral, sensorineural hearing loss to perform similarly to normal hearing listeners on a speech-in-noise task (i.e., they required the same signal-to-noise ratio to achieve 50% understanding). When the noise source was moving around the listener, only the second-order (three-microphone) system set to an adaptive directional response (where the polar pattern changes due to the change in noise location) allowed a group of hearing-impaired individuals with mild-to-moderate sensorineural hearing loss to perform similarly to young, normal-hearing individuals.

Using a signal cancellation technique to assess adaptive directivity of hearing aids

“…By knowing the characteristics of adaptive systems, the researchers can design the laboratory setup to maximize the directional benefit. For example, if research is designed to investigate the adaptive system of HA1 by moving noises ͑e.g., Bentler et al, 2004b͒, and if the moving noise is high frequency in spectrum, one may not see any difference between the adaptive and fixed directional modes. If a researcher used HA3 in a study, and placed the noise source at 110°͑or the corresponding azimuth angle if HA3 is mounted on a man's head͒, he/she might not see much directional benefit from this adaptive DMHA.…”

“…Although the effectiveness of these instruments has not been observed in field trials ͑Palmer et al, 2006͒, the efficacy of the adaptive DMHA has been proven in some laboratory environments ͑Bentler et al., 2004b;Ricketts and Henry, 2002͒. Therefore, many manufacturers currently implement adaptive directional technology on newly designed hearing aids.…”

Speech-clarity judgments of hearing-aid-processed speech in noise: Differing polar patterns and acoustic environments

“…None of the participants in Group HI-I had been fit with a hearing aid having directional microphone capabilities, and only two participants in Group HI-E had devices configured with directional microphones. A group of 12 adults with normal-hearing sensitivity (Group NH) was also included, and served as a standard-comparison group with respect to their increased auditory sensitivity (Jerger & Thelin, 1968;Bentler et al, 2004b). This group was included to determine the extent to which responses of listeners with normalhearing sensitivity can be generalized to listeners with mild-tomoderate sensorineural hearing impairment.…”

Wireless technology designed to provide true binaural amplification

“…9 Independent research on this instrument showed encouraging findings, both for the fixed polar pattern and for the adaptive directional options. [10][11][12] In general, researchers found that the directional technology allowed for improved speech intelligibility in background noise for a variety of listening conditions. The directional optimization system in this new instrument has been expanded and has several different aspects.…”