Hearing aid benefit in adults with self-reported hearing difficulty yet normal pure-tone audiograms

The National Institute on Deafness and Other Communication Disorders awarded Duke University $707,920 on July 10, 2026, under the Research Related to Deafness and Communication Disorders program (CFDA 93.173) to conduct a randomized controlled trial examining whether low-gain, clinician-fitted hearing aids benefit adults with functional hearing difficulties—individuals who report difficulty following conversations in adverse listening environments yet present with clinically normal hearing on standard audiologic exams.

The research uses a single-blinded, 2×2 factorial, randomized cross-over controlled trial design with a total sample of 100 adults across two sites. Participants will be randomly assigned to either an open-fit or closed-fit hearing aid group, then further assigned to either signal-to-noise neutral or signal-to-noise enhancement treatment arms. Each participant completes a 4-week trial with their assigned treatment before crossing over to the alternate treatment arm, with a 4-week washout period between arms and outcome assessments at the end of each 4-week treatment period. The study addresses a neglected population of help-seeking patients who receive no appropriate audiologic care despite their communication difficulties.

Work is performed in Durham, North Carolina. The period of performance runs from July 10, 2026, through April 30, 2031. This is a project grant, the largest assistance category under the NIDCD program.

Abstract

Millions of adults report having difficulty following conversations in adverse listening environments like noisy backgrounds or groups, yet present with clinically normal hearing on the standard audiologic exams. This phenomenon is known as functional hearing difficulties (FHD); hearing difficulty yet normal test results. Adults with FHD are motivated to seek help, however they are often informed that their hearing is 'normal' by their audiologist without any discussion of potential treatment options, such as low-gain hearing aids. They are left dissatisfied with their clinical experience, feeling dismissed by the audiologist, resulting in continued poor communication and reduced quality of life. Therefore, adults with untreated FHD represent a neglected population of patients who exhibit help-seeking behavior, yet do not receive appropriate audiologic care. The overarching goal of the proposed research is to improve the hearing healthcare of adults with FHD who present clinically with 'normal' hearing thresholds. The current proposal will examine if low-gain, clinician-fitted hearing aids provide benefit for adults with FHD, and if so, what hearing aid features drive benefit. We will use a single- blinded, 2X2 factorial, randomized cross-over controlled trial design. A total sample of 100 adults with FHD (across two sites) will be included. They will be randomly assigned to either an open-fit or closed-fit group (factor 1) and then will be further assigned to either a signal-to-noise neutral treatment arm VS a signal-to-noise enhancement treatment arm (factor 2). They will complete a 4-week trial with their assigned factor 2 treatment arm before crossing over to the other hearing aid treatment arm. There will be a 4-week washout period between the two treatment arms, with outcome assessments being completed at the end of each 4-week treatment arm. They also will complete an open-ended survey at the end of each treatment arm to explore patient experience and benefit as described in their own words. Treatment outcomes will be examined to determine if hearing aid use leads to meaningful improvement in self-reported outcomes and to quantify the relative hearing aid benefits. Finally, we will explore patient characteristics and baseline test results that are most associated with treatment outcomes that may help inform a test battery to better assess adults with FHD. This will be accomplished by incorporating additional tests in our baseline assessment above and beyond the standard audiologic test battery and that TAP into more complex domains of supra-threshold auditory and speech processing. These include patient characteristics, speech-in-noise tests, select tests of auditory processing, and self-reported hearing function measures. The results of this study will determine the efficacy of hearing aids as a treatment for FHD in adults, and what hearing aid features provide benefit. In addition, the results will inform if additional measures above and beyond the standard audiogram could be administered in the clinic to help to identify treatment candidacy for adults with FHD.