| Study summary: |
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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. |