Hearing loss is the most common service-connected disability nationwide in the VHA system, with hearing aids providing the primary treatment option. Although the benefits of hearing-aid use are clearly established,~16-30% of adults who have hearing aids do not use them. Several factors are believed to result in non-use of traditional hearing aids, including (1) poor fit and comfort, (2) poor cosmetics, (3) whistling feedback, (4) occlusion, and (5) difficulty understanding speech in noise.
Recently, the open canal (OC) hearing-aid style has become a viable approach to addressing address many of the problems resulting in non-use of traditional hearing aids, particularly for individuals with mild to moderately-severe hearing loss. Although an OC hearing aid has many potential advantages, there also are potential limitations. For example, the maximum low and high-frequency gain available with an OC fitting is less than that available from traditional custom (TC) hearing-aid fittings, which could result in less than optimal amplification for some individuals. In addition, directional microphone benefits for speech understanding in noise, available with TC fittings, likely will be limited with OC fittings due to the loss of low-frequency gain (Ricketts et al., 2005).
Since both OC and TC fittings are appropriate for listeners with mild to moderately-severe hearing losses, evidence is needed to determine which style of hearing aid is preferred by a majority. Currently, OC fittings use a small behind-the-ear (BTE) hearing aid coupled to a thin tube or plastic covered wire ending in a vented "open" eartip. When a TC fitting is used with patients with similar hearing losses, the majority are either an in-the-ear (ITE) or in-the-canal (ITC) .In the proposed study a comparison will be made between OC vs. TC fittings.. In addition to this primary comparison, preference for one of two OC hearing aids, viz., OC instruments with receiver in the ear (OCRITE) and the OC instruments with receiver in the hearing-aid case (OCRIHA), will be determined. The outcomes of the OCRITE, OCRIHA, and TC hearing-aid use related to the factors of: (1) comfort and cosmetics, (2) subjective occlusion, (3) objective occlusion, (4) sound quality for external sounds, (5) feedback, (6) ease of use, (7) audibility, (8) aided signal-to-noise ratio (SNR) benefit, and (9) localization, will be measured in a large (n = 288), randomized-controlled, three-site (Bay Pines, Mountain Home, and Nashville) clinical trial, utilizing a three-period (two months each), cross-over design. A total of 13 variables will be measured for the 9 hearing-aid fitting and style-related factors. At the end of the study, participants will rank order their preferences for the three hearing aid fittings to determine (1) the preferred OC fitting (OCRITE vs. OCRIHA) and (2) whether the highest ranked OC fitting or the TC fitting is preferred. Preferred OC vs. TC difference scores will be calculated for all relevant variables. The ability of the differences scores to predict the preferences of the participants for an OC vs. TC hearing aid will be determined, in order to develop an evidence-based hearing aid selection model. |
