Efficacy of a Coupler-based Fitting Approach for Experienced Users Receiving Replacement Hearing Aids

Efficacy of a Coupler-based Fitting Approach for Experienced Users Receiving Replacement Hearing Aids

Hearing loss is among the top service-connected disabilities in Veterans. Hearing aids are the primary intervention for hearing loss. Half of the hearing aids dispensed in the VA are to Veterans who are receiving replacement amplification. Many Veterans would like their replacement hearing aids mailed to them, but they are required to travel to the clinic so that the fit of the hearing aid can be verified. There are standard fitting procedures, such as those used in infants and children, that use a coupler to simulate the patient's real ear to verify the hearing aid fitting. The results of this study should determine the efficacy of a coupler-based hearing-aid fitting protocol that would not require the Veteran to attend the fitting appointment, thereby contributing to improved Veteran-Centric care.

In the VA system, hearing loss is the second-most common service-connected condition affecting 933,182 Veterans, exceeded only by tinnitus which affects 1,121,709 Veterans (data from Veterans Benefit Report for Fiscal Year 2016). In FY 2016, the VA dispensed 750,075 hearing aids at a net procurement of nearly $270 million (report generated from VA Denver Acquisition and Logistics Center [DALC] Remote Order Entry System [ROES]). Half of the hearing aids dispensed were to experienced hearing aid users receiving replacement hearing aids (Dennis, 2014). VA Audiology caseload is significant and Veterans can experience long wait-times for fitting appointments to obtain new hearing aids (Office of the Inspector General, 2014).

The purpose of the fitting appointment is to program and verify the hearing aids and orient the patient to hearing aid use/care. For patients obtaining replacement hearing aids, the orientation typically is unnecessary, and the programming is simplified; consisting mainly of matching the individual's real-ear aided response (REAR) and hearing aid output to appropriate target values. In contrast to adults, REAR measurements are not well-tolerated by children due to the requirement for placement of a probe tube in the ear canal. Therefore, a hearing aid fitting procedure that circumvents the need for in situ REAR measurements (real ear coupler difference or RECD) is the standard-of-care (SoC) for children. Considerable research clearly has shown the equivalency of in situ REAR and RECD fitting procedures (e.g., Moodie et al., 1994). RECD fitting procedures rarely are used with adults; however, such an approach could preclude the need for direct physical contact with the patient at the time of the hearing aid fitting. Three experiments are proposed. The purpose of the first study is to evaluate coupler-based fitting approach for groups of experienced users obtaining replacement hearing aids and compare the accuracy of those fittings to the prescription and their outcomes to norms. The second study aims to develop correction factors for venting of open-fit hearing aids. The third study will focus on comparing coupler-based fittings of open-fit hearing aids (using correction factors developed from study two results) to an SoC (active control) group who will have their open-fit hearing aids fitted in face-to-face appointment via standard in situ REAR procedures. In Study 1 and 3, both groups will return for in situ REARs and self-report outcomes assessment one month after the hearing-aid fitting. The results of this study should determine the efficacy of a RECD-based, hearing-aid fitting approach for experienced hearing-aid users who are receiving replacement hearing aids consisting of a variety of styles. If the approaches are equivalent, then this study will provide an evidence-based, RECD fitting approach that should result in greater patient satisfaction and reduced costs.

Inclusion Criteria:

Study 1 and 3

• experienced hearing-aid users who are obtaining replacement VA-issued hearing aids of the same style and manufacturer as their current hearing aids
• no more than a moderate sensorineural hearing loss (defined as < 60 dB HL pure-tone average at 500, 1000, and 2000 Hz AU)
• symmetrical hearing between the ears as defined as no more than a 20 dB difference in pure-tone thresholds at two consecutive frequencies
• 50% word-recognition abilities in quiet as measured during the diagnostic audiologic evaluation
• An education-adjusted score of >21 on the Montreal Cognitive Assessment
• ability to read and write in English

Study 2 Veterans aged 18-85 years with sensorineural hearing loss

Exclusion Criteria:

Study 1 and 3

• outer or middle ear pathology as determined by otoscopy, immittance, and/or audiometric testing (e.g., conductive or mixed losses)
• a significant change in hearing on audiogram obtained during the current study and that obtained when fitted with the current (to-be replaced) hearing aids as defined by a 15 dB decline in thresholds at three consecutive frequencies in either ear
• lack of phone or non-use of the phone
• unwilling or unable to be mailed hearing aids
• co-morbid condition that would preclude their participation

Study 2

• co-morbid condition that would preclude their participation
• outer or middle ear pathology as determined by otoscopy, immittance, and/or audiometric testing (e.g., conductive or mixed losses)