Self-Adjustment of Hearing Aid Amplification for Lower Speech Levels: Independent Ratings, Paired Comparisons, and Speech Recognition

Purpose: Self-adjustment of hearing aid amplification enables wearers to customize the hearing aid output to match their preferences and could become an important tool for programming direct-to-consumer devices for people with mild-to-moderate hearing loss. One risk is that user-selected settings may provide inadequate audibility. This study assessed that risk by quantifying relationships between self-adjusted settings, subjective preferences, and speech recognition performance using speech at low levels in quiet, where achieving high speech audibility requires sufficient amplification.

Method: Fifteen people with symmetric, mild-to-moderate sensorineural hearing loss self-adjusted hearing aid amplification while listening to speech in quiet at 45, 55, and 65 dBA. After self-adjustment, 11 participants made blinded ratings of their self-adjusted fit, their NAL-NL2 prescriptive fit, and experimenter-created fits with reduced gain. Participants completed blinded paired comparisons and sentence recognition assessments using these settings.

Results: The gain of self-adjusted fits showed a large range of variability between participants. On average, self-adjusted gain was similar to NAL-NL2 prescribed gain for input signals of 55 dBA and slightly greater than prescribed gain for 45-dBA signals. Speech recognition scores for NAL-NL2 fits were consistently high, and differences in speech recognition results were strongly correlated with the overall preferences obtained from paired comparisons.

Conclusions: Self-adjusted fits are highly variable between individuals for low-audibility conditions. Nonetheless, self-adjusted fits are at least as satisfactory as NAL-NL2 fits, and listeners tend to disfavor settings that result in poorer speech recognition. The findings argue against concerns that self-adjustment will result in inadequate audibility compared to prescribed settings.