Intervention for Reduced Sound Tolerance

Hyperacusis is the intolerance to sound levels that normally are judged acceptably loud to
others. The presence of hyperacusis (diagnosed or undiagnosed) can be an important reason
why some persons reject amplified sound from hearing aids. Tinnitus Retraining Therapy
(TRT), originally proposed for the treatment of persons with debilitating tinnitus, offers
the significant secondary benefit of increased Loudness Discomfort Levels (LDLs), along with
expansion of the dynamic range for loudness. TRT uses both counseling and sound therapy
from daily exposure to soft sound from bilateral noise generator devices (NGs) and has been
promoted as an intervention for hyperacusis. The hypothesis of this investigational study
is that the counseling and sound therapy principles used in TRT can be applied successfully
to treat hearing-impaired hearing-aid candidates with reduced sound tolerance who are
otherwise should benefit from hearing aids.

The current study is being implemented as a randomized, double-blind, placebo-controlled
trial to assess the efficacy of a TRT-based intervention for reduced sound tolerance in
hearing-aid eligible persons with hyperacusis and/or restricted dynamic ranges. The trial
design allows for the evaluation of the efficacy of partial treatments, including the
effects of counseling separately from the effects of sound therapy. Forty hearing-impaired
subjects (without primary tinnitus) are being assigned randomly to one of four treatment
groups: 1) full treatment, both counseling and sound-therapy (n=10); 2) counseling with
placebo sound therapy (n=10); 3) sound therapy without counseling (n=10); and 4) placebo
sound therapy without counseling (n=10). Subjects are being evaluated at least monthly,
typically for five months or more, on a variety of audiometric tests, including LDLs, the
Contour Test for Loudness for tones and speech, word recognition measured at each session's
comfortable and loud levels, and electrophysiological measures.