Benefits of a low processing delay for first-time hearing aid users in real life

Open-fit hearing aids combine amplified and direct sound at the eardrum. The inevitable processing delay of hearing aids can therefore produce comb-filtering artifacts that may affect sound quality, own-voice perception, and overall hearing aid satisfaction. This field study investigated whether reducing processing delay to 0.5 ms provides benefits for first-time hearing aid users. In a three-week field trial, participants wore two pairs of hearing aids with 0.5 ms (low delay, LD) and with 8 ms delay (high delay, HD). During an initial familiarization week, participants directly compared the two pairs of devices in selected listening situations. This was followed by a randomized crossover trial in which each pair was worn for one week. Daily ratings of satisfaction, sound quality, and own voice perception were collected. At the end of each week, participants completed the International Outcome Inventory for Hearing Aids (IOI-HA), additional satisfaction questionnaires including assessments of own-voice perception, and the hearing-related lifestyle questionnaire (HEARLI-Q). Finally, participants indicated their overall device preference. Results showed higher total IOI-HA scores for LD, with higher scores for both introspection and interaction. HEARLI-Q responses indicated greater hearing aid satisfaction and reduced perceived difficulty for LD processing. While there was no difference in objective speech intelligibility, subjective ratings of sound quality, hearing aid satisfaction, naturalness of sound, own voice perception, and listening effort consistently favored LD processing. These findings suggest that processing delay is an important determinant of real-world hearing-aid experience and hence may support first-time hearing-aid adoption. This is a preprint to be submitted for peer review.