Over-the-counter hearing aids and integrated health-monitoring sensors: a review of clinical evidence and implementation.

The FDA's 2022 over-the-counter (OTC) hearing aid rule created a new access pathway for adults with mild to moderate hearing loss. Hearing aids have also begun incorporating health-monitoring sensors. This PRISMA-guided narrative review evaluates the clinical evidence for OTC hearing aids and the validation status of health sensors in hearing aids, based on 59 studies identified from PubMed, Scopus, Web of Science, and the Cochrane Library and published between 2020 and 2026. In most randomized trials, self-fitted OTC hearing aids produced outcomes noninferior to professionally fitted devices, though one trial found audiologist-fitted hearing aids achieved better results. Consumer adoption has been incremental, with most OTC users still seeking professional support. Usability assessments found that many older adults had difficulty completing self-fitting tasks without error, and current self-fitting interfaces may not guide users toward optimal amplification. Accelerometry-based hearing aid sensors for gait analysis and energy expenditure demonstrated accuracy comparable to established reference and consumer devices. A prototype multi-sensor platform successfully measured temperature, oxygen saturation, heart rate, and respiration rate. Health sensors in hearing aids are technically validated but clinically unproven, as no study has linked sensor data to improved patient outcomes. If outcome studies confirm these uses, sensor-equipped hearing aids could become useful in geriatric medicine, cardiovascular monitoring, and fall prevention, linking audiology to wider medical care. Getting there will require prospective clinical trials, standard validation methods, and regulatory frameworks for dual-purpose devices.