Effect of Microphone Directionality in Hearing Aids on Speech Perception from Different Distances in Individual with SNHL

Abstract

One of the most common complaints among individuals with hearing impairment is difficulty understanding speech as the distance from the speaker increases, even while using hearing aids. This study aimed to investigate the effect of distance on speech identification performance in individuals with sensorineural hearing loss, under two hearing aid microphone conditions: directional (ON) and omnidirectional (OFF). Twenty adults with moderate, flat or sloping sensorineural hearing loss participated in the study. Recorded word lists were presented at three distances1m, 3m, and 5musing a calibrated loudspeaker. The intensity levels were adjusted to compensate for propagation loss based on the inverse square law, and verified at each distance using a sound level meter (SLM). All participants were fitted with hearing aids programmed to match their prescribed targets, and real ear measurements (REM) were performed to ensure appropriate gain and output. Speech identification scores were obtained in both microphone conditions across all three distances. The results revealed a statistically significant decline in speech identification scores with increasing distance in both the conditions. The results highlight the limitations of hearing aid amplification in long-distance listening scenarios and emphasize the need for advanced microphone sensitivity and directional features which can improve hearing aid performance at moderate distances. There is a need for additional support strategies in real-world environments for hearing aid users when listening speech from a distance.