Challenges of designing an over-the-counter medical device for adults with mild-to-moderate hearing loss (Preprint)

Abstract

Only 15% of the nearly 30 million Americans with hearing loss use hearing aids, partly due to high cost, stigma, and limited access to required prior medical evaluations. Hearing impairment in adults can lead to social isolation and depression and is associated with an increased risk of falls as well as dementia. Given the persistent barriers to hearing aid use, the Food and Drug Administration (FDA) recently issued a final rule to allow over-the-counter hearing aids to be sold directly to adult consumers with perceived mild-to-moderate hearing loss at pharmacies, stores, and online retailers without seeing a physician or licensed hearing health care professional.

We evaluated the safety and usability of an over-the-counter hearing aid prior to FDA approval and market release.

We first conducted a formative usability test of the device and associated App with 5 intended users to identify outstanding safety and usability issues. Following design modifications, we performed a second round with 15 intended users of the device. Participants were asked to complete 2-5 tasks, as if they were using the hearing aid in real life. After each task, participants rated the task difficulty. At the end of each session, participants completed a 10-question knowledge assessment and the system usability scale (SUS) and then participated in debriefing interviews to gather qualitative feedback. All sessions were video recorded and analyzed to identify use errors and design improvement opportunities. We concurrently conducted a test with 21 non-intended users (i.e., users with contraindications to use) to ascertain if consumers could determine when they should not use the device, based on the packaging, instructions, and labeling.

In all three usability tests, usability issues were identified. There were minimal safety-related issues with the device. Round 1 testing led to several design modifications which then increased task success in Round 2 testing. Participants had the most difficulty with the task of pairing the hearing aids to the cellphone. Participants also had difficulty distinguishing the right and left earbuds. Non-intended users did not always understand device contraindications (e.g., tinnitus, severe hearing loss). Overall, test findings informed eight actionable design modifications that improved device usability and safety.

This study evaluated the usability and safety of an over-the-counter hearing aid for adults with mild-to-moderate hearing loss. Human factors engineering methods identified opportunities to improve the safety and usability of this direct-to-consumer medical device for individuals with perceived mild-moderate hearing loss.