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

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.

Study 1. Participants obtaining replacement in-the-ear (ITE) or behind-the ear (BTE) hearing aids will be assigned to the ITE or BTE coupler-based fitting groups. Study 2: Participants will be fitted with open-fit hearing aids using simulated audiograms. Study 3. Participants obtaining replacement open fit or receiver-in-the canal hearing aids will be randomly assigned to the standard of care fitting groups (open or closed) or the coupler-based fitting groups (open or closed).

Experienced users of in-the-ear (ITE) hearing aids will receive replacement ITE hearing aids that are fitted and verified in a test box coupler, then mailed to the patient for a 4-week field trial.

Experienced users of behind-the-ear (BTE) hearing aids will receive replacement BTE hearing aids that are fitted and verified in a test box coupler, then mailed to the patient for a 4-week field trial.

Participants with hearing loss will be fitted monaurally with 12 stock non-custom, receiver in the canal (RIC) or receiver in the aid (RITA) hearing aids using the standard in-situ approach and test box measures will be made of each fitting to develop correction factors for these styles.

This group will serve as the active comparator group for experienced hearing aid user receiving replacement receiver in the canal (RIC) or receiver in the aid (RITA) hearing aids with OPEN coupling using the standard of care approach, then undergoing a 4-week field trial.

This group will serve as the active comparator group for experienced hearing aid user receiving replacement receiver in the canal (RIC) or receiver in the aid (RITA) hearing aids with CLOSED coupling using the standard of care approach, then undergoing a 4-week field trial.

Experienced hearing aid user receiving replacement receiver in the canal (RIC) or receiver in the aid (RITA) hearing aids with OPEN coupling that are fitted and verified in a test box coupler, then mailed to the patient for a 4-week field trial.

Experienced hearing aid user receiving replacement receiver in the canal (RIC) or receiver in the aid (RITA) hearing aids with CLOSED coupling that are fitted and verified in a test box coupler, then mailed to the patient for a 4-week field trial.

Experienced users of in-the-ear (ITE) hearing aids will receive replacement ITE hearing aids that are fitted and verified in a test box coupler, then mailed to the patient for a 4-week field trial.

Experienced users of behind-the-ear (BTE) hearing aids will receive replacement BTE hearing aids that are fitted and verified in a test box coupler, then mailed to the patient for a 4-week field trial.

This group will serve as the active comparator group for experienced hearing aid user receiving replacement receiver in the canal (RIC) or receiver in the aid (RITA) hearing aids with OPEN coupling using the standard of care approach, then undergoing a 4-week field trial.

This group will serve as the active comparator group for experienced hearing aid user receiving replacement receiver in the canal (RIC) or receiver in the aid (RITA) hearing aids with CLOSED coupling using the standard of care approach, then undergoing a 4-week field trial.

Experienced hearing aid user receiving replacement receiver in the canal (RIC) or receiver in the aid (RITA) hearing aids with OPEN coupling that are fitted and verified in a test box coupler, then mailed to the patient for a 4-week field trial.

Experienced hearing aid user receiving replacement receiver in the canal (RIC) or receiver in the aid (RITA) hearing aids with CLOSED coupling that are fitted and verified in a test box coupler, then mailed to the patient for a 4-week field trial.

The primary outcome of interest is based on fitting accuracy of each ear (i.e., deviation of real ear aided response from prescriptive targets across frequency measured in decibels (dB)).

Abbreviate Profile of Hearing Aid Benefit (APHAB; Cox and Alexander, 1995). The APHAB contains 24 items that assess hearing problems across four subscales including: (1) ease of communication, (2) background noise, (3) reverberation, and (4) aversiveness to sounds. Items are answered using a 7-item response scale ranging from never (1%) to almost always (99%). Items typically are answered in unaided and aided conditions. Higher numbers indicated more problems. The difference in scores between the two conditions is a measure of benefit. For this study, however, the aided-aided version of the APHAB will be used. Study 1 and 3.

Client-Oriented Scale of Improvement (COSI; Dillon, James, & Ginis, 1997). The listener nominates up to five listening goals on the COSI. After hearing-aid use, the listener assesses two outcomes for each goal. One outcome is the "degree of change" relative to the patient's unaided experience. Responses are recorded on a categorical scale from 'worse' to 'much better.' The second outcome is the final satisfactory "aided" ability for each goal as measured on a categorical scale from hardy ever (10%) to almost always (95%). The percentage of 'better' and 'much better' responses and the average of the final ability will be calculated across goals. Study 1 and 3.

International Outcomes Inventory for Hearing Aids (IOI-HA; Cox et al., 2000). The IOI-HA consists of seven items including (1) use, (2) benefit, (3) satisfaction, (4) residual activity limitation, (5) residual participation restriction, (6) impact on others, and (7) quality of life. Each item has a unique 1-5 response scale. Scores range from 7-35 with higher scores indicating higher outcomes. Study 1 and 3.

Satisfaction with Amplification in Daily Life (SADL) (Cox and Alexander, 1999). The SADL questionnaire has 15 items that examine self-reported hearing-aid satisfaction. The following four subscales are included: (1) positive effect, (2) negative features, (3) personal image, and (4) service and cost. For the current study, item 14 on the service and cost subscale will not be used as the Veterans are not charged for the cost of their bilateral hearing aids. The SADL uses a 7-item response scale in 1-unit steps, 1 (poorest) to 7 (highest) for each item, which are averaged for each subscale and total scale score. Study 1 and 3.

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)