Closedness of Acoustic Coupling and Audiological Measures Are Associated with Individual Speech-in-Noise Benefit From Noise Reduction in Hearing Aids.

The study is correlational and did not randomise patients to coupling types, so it cannot show that making a coupling more closed causes more benefit. Different earpiece types were chosen during fitting, especially among German participants, and this confounds intentional coupling differences with patient differences; the coupling correlation was not significant in Japanese participants who all had the same earmold type. Benefit was measured in one spatial speech-in-noise scenario with front target speech and noise from the sides, so it may not apply to all everyday listening situations. The tested hearing aids were from one manufacturer and the strongest directional/noise reduction setting was used; the separate contributions of directional processing and noise reduction were not tested. Some data were missing: 8 participants dropped out, acoustic coupling measurements were available for 112 participants, and unaided speech-in-noise scores could not be measured for 23 participants. Measurement uncertainty limited how much benefit variance could be explained, even if factors were perfect. Two authors owned stocks in companies connected to the tested hearing aids and test equipment, and the work was funded by the William Demant Foundation.

GJ and SL own stocks in Demant, which owns Oticon, the hearing aid manufacturer, and Interacoustics, GSi, and MedRx, manufacturers of equipment used for the ACT test. The authors stated no potential conflicts of interest for the research, authorship, or publication. Funding was from the William Demant Foundation.

Do not conclude that making a hearing aid coupling more closed will improve speech-in-noise performance for every patient. The study is correlational, and the coupling association was confounded by different earpiece types being chosen during fitting; it was not significant when all participants had the same earmold.