Modification of Loudness Discomfort Level: Evidence for Adaptive Chronic Auditory Gain and Its Clinical Relevance

Abstract

A vexing problem in audiology has been the modification of sound tolerance. Sound intolerance and restricted dynamic ranges are common conditions that audiologists encounter daily in the hearing-impaired population, especially in the fitting of hearing aids. To date, no clinical protocol has proven to be successful for modifying sound tolerance among the hearingimpaired population. This report describes the use of low-level, broadband sound in a habituation-based treatment protocol termed Tinnitus Retraining Therapy (TRT). Over the past decade, TRT has become increasingly popular as an intervention for severe tinnitus and hyperacusis. One of the primary treatment effects from TRT is that over the course of the intervention the patient's loudness discomfort level (LDL) thresholds routinely shift to higher levels. Ostensibly, the resulting higher LDL thresholds reflect treatment effects associated with the resetting of a plastic and adaptive auditory gain process that somehow regulates the supra-threshold sensitivity of the auditory system in response to chronic changes in the sound input from the auditory periphery to the central auditory pathways. Tinnitus patients with significant hearing losses and sound tolerance problems respond successfully to TRT and, as a consequence, their LDL thresholds are usually elevated (improved) and, concomitantly, their dynamic ranges are expanded. Many of these patients, who before the TRT intervention could not tolerate amplified sound, then have been able to make a comfortable transition into appropriate amplification after treatment. In principle, TRT would seem to offer a viable intervention strategy for modifying sound tolerance in the general hearingimpaired population. If so, then the clinical applications of TRT principles may extend well beyond the treatment of tinnitus and hyperacusis.

Brainstem plasticity and modified loudness following short-term use of hearing aids

“…Likewise, an "over-amplification" of stimulus-evoked neural activity may lead to hyperacusis and sound tolerance problems. The frequency-invariant changes for loudness in the present study are consistent with sound tolerance problems which also tend to occur over a broad range of frequencies, despite normal hearing thresholds at some frequencies (Formby and Gold, 2000;Norena and Chery-Croze, 2007). Abnormally high neural gain forms the basis for desensitizing sound therapies when treating hyperacusis and sound tolerance problems (Baguley and Andersson, 2007).…”

Guide to conducting tinnitus retraining therapy initial and follow-up interviews

“…Many patients with tinnitus use earplugs or earmuffs to prevent their tinnitus from becoming worse. Such action in fact will result in the tinnitus sounding louder, because of the occlusion effect, and is reported to cause reduced loudness tolerance [29][30][31][32][33][34][35]. It is thus an important issue, but the examiner must use caution during the questioning so as not to give patients the new concern that sound might make their tinnitus worse.…”

The Role of Audiologic Evaluation in Progressive Audiologic Tinnitus Management

“…Formby, C., & Gold, S. L. (2002). Modification of loudness discomfort level: Evidence for adaptive chronic auditory gain and its clinical relevance.…”