The impact of directional listening on perceived localization ability

An important purpose of hearing is to aid communication. Because hearing-in-noise is of primary importance to individuals who seek remediation for hearing impairment, it has been the primary objective of advances in technology. Directional microphone technology is the most promising way to address this problem. Another important role of hearing is localization, allowing one to sense one's environment and feel safe and secure. The properties of the listening environment that are altered with directional microphone technology have the potential to significantly impair localization ability. The purpose of this investigation was to determine the impact of listening with directional microphone technology on individuals' self-perceived level of localization disability and concurrent handicap. Participants included 57 unaided subjects, later randomly assigned to participate in one of three aided groups of 19 individuals each, who used omni-directional microphone only amplification, directional microphone only amplification, or toggle-switch equipped hearing aids that allowed user discretion over the directional microphone properties of the instruments. Comparisons were made between the unaided group responses and those of the subjects after having worn amplification for three months. Additionally, comparisons between the directional microphone only group responses and each of the other two aided groups' responses were made. No significant differences were found. Hearing aids with omni-directional microphones, directional-only microphones, and those that are equipped with a toggle-switch, neither increased nor decreased the self-perceived level of ability to tell the location of sound or the level of withdrawal from situations where localization ability was a factor. Concurrently, directional-microphone only technology did not significantly worsen or improve these factors as compared to the other two microphone configurations. Future research should include objective measures of localization ability using the same paradigm employed herein. If the use of directional microphone technology has an objective impact on localization, clinicians might be advised to counsel their patients to be careful moving in their environment even though they do not perceive a problem with localization. If ultimately no significant differences in either objective or subjective measures are found, then concern over decreases in quality of life and safety with directional microphone use need no longer be considered.