Efficacy of a Hearing Aid Noise Reduction Function.

Only 32 participants completed testing, and they were experienced hearing-aid users with symmetrical moderate to severe hearing loss, so results may not apply to new users, people with milder or profound loss, or asymmetric hearing loss. The study tested one Phonak hearing aid and one noise reduction algorithm, so findings may not transfer to other hearing aids or noise reduction features. Outcomes were measured in a laboratory with controlled noise levels, not in real-world listening, and the paper says clinical significance and real-life benefit need further study. Noise reduction was tested mainly at moderate or positive signal-to-noise conditions; the paper notes that noise reduction may not work as well when speech is buried in noise. There was large variability in acceptable noise level scores, and only the off-versus-NR20 difference reached the paper's stated clinically important change. Acceptable noise level and speech reception threshold scores did not correlate, so noise tolerance did not explain speech reception gains.

The study was funded by the Research Support Scheme 2017/2018 of the Department of Special Education and Counselling at the Education University of Hong Kong and by Phonak, China, the maker of the hearing aids tested.

Do not assume that turning noise reduction to the strongest setting will make speech clearer. In this study, NR20 did not improve speech reception over NR10 and was less preferred than the other noise reduction settings.