Hearing Aids for Veterans With Functional Hearing Difficulties

At least 10% of Veterans seeking help in VA audiology clinics have clinically normal audiograms, a figure that broadly confirms a recent prevalence study indicating that 33.6% of current active-duty military Service Members are at risk of hearing and communication deficits despite having normal-hearing thresholds. While a considerable amount of research effort over the past 20 years has been devoted to understanding the potential causes for hearing difficulties in patients with normal hearing sensitivity, comparatively little research effort has been devoted to rehabilitation and improvement of function for these patients. This predicament has left audiologists and other medical professionals with very few evidence-based options to provide care for the large segment of help-seeking Veterans struggling with functional hearing difficulties. Currently, audiologic standard of care (SOC) for these patients involves reassurance of normal hearing and providing general communication tips, though evidence suggests that many patients are unsatisfied with this approach and request further testing and rehabilitation options. To help address patient concerns, many VA audiologists are now prescribing hearing aids though there is very little data on whether these devices improve functional outcomes for patients with self-reported hearing difficulties and normal hearing sensitivity. Therefore, the purpose of this study is to compare the efficacy of device-based rehabilitation options with current standard of care for Veterans with self-reported hearing and communication problems, and to identify subgroups in the sample that may benefit differently depending upon patient-specific characteristics and needs. The general hypothesis is that most Veterans with hearing difficulties and normal audiograms will benefit from device-based auditory rehabilitation as reflected by decreases in perceived hearing handicap. However, the amount of benefit will vary according to patient-specific characteristics including auditory, psychological and cognitive factors in combination with the type and severity of auditory dysfunction experienced by the patient.

All study participants will be Veterans with normal to near-normal pure-tone sensitivity but with moderate to severe perceived hearing handicap who are interested in seeking professional help. Participants will be interviewed to gather data regarding their hearing difficulties, including the context and impacts of difficulties as well as goals for auditory rehabilitation. Next, participants will undergo assessments of peripheral and central auditory system function including electrophysiological and behavioral measures and cognitive and psychological status assessed using established NIH Toolbox® measures. Participant medical charts will be reviewed to gather data on comorbid conditions and previous exposures known to be risk factors for developing auditory processing difficulties. These data will be compiled to provide an estimate of the distribution of characteristics likely to impact auditory function and response to intervention among Veterans seeking help for functional hearing difficulties. Participants will then be randomized into one of following three intervention arms: 1. SOC, 2. SOC + hearing aids, or 3. SOC + hearing aids with remote microphone. Outcomes will be measured at two- and six-months post-intervention. The primary outcome measure is the Hearing Handicap Inventory for Adults. Secondary outcome measures are aimed at identifying the underlying mechanisms and potential mediators that influence whether and how participants receive benefit from hearing devices. These will include measures of speech understanding in quiet and noise, objective and subjective listening effort, electrophysiological measures of neural responses to sound, and interviews to learn more about participants' perceptions of the intervention. Interaction effects will be estimated between treatment arm and patient characteristics to identify key moderating factors that influence the degree and direction of benefit associated with different treatment strategies. This information can then be used to inform both clinical decision making for individual patients and the design of future intervention studies.

Inclusion criteria

• Veteran eligible for VA Healthcare
• Ability to travel to VA Portland Medical Center for repeated visits
• Pure-tone thresholds of no more than 30 dB HL at frequencies between 500 and 3000 Hz, and no more than 40 dB HL at 4000 Hz
• HHIA scores of 24 or greater indicating moderate to significant perceived hearing handicap

Exclusion criteria

• Conductive hearing loss or other significant otologic problems
• Non-native English speakers
• Inability to perform experimental tasks
• Pure-tone interaural threshold asymmetries greater than 15 dB between 250 and 4000 Hz