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.

Inclusion criteria

• One hundred adults, who have hearing losses and who have unsuccessfully used hearing aids because of tolerance problems (hyperacusis).
• All subjects must be committed to the use of amplification if and when the hyperacusis is resolved.
• Each patient will have demonstrable hyperacusis, but will be free from tinnitus, and must be willing to wear and usc binaural in-the-ear sound generators (or placebo generators) chronically as prescribed.

Exclusion criteria

• Evidence of conductive, mixed hearing loss, or CNS disease.
• Abnormal tone and/or acoustic reflex decay will also preclude subject participation because of the potential for these patients to adapt to the chronic sound therapy.