Decreased Sound Tolerance and Tinnitus Retraining Therapy (TRT)

TLDR

TRT aims to habituate autonomic activation triggered by auditory signals, targeting shared neurophysiological pathways implicated in tinnitus, hyperacusis, and misophonia to reduce sound‑related distress. Sound therapy is intended to diminish the strength of auditory‑evoked autonomic signals. TRT leverages the hypothesis that heightened auditory pathway gain amplifies tinnitus signals, explaining the frequent coexistence of tinnitus and hyperacusis.

Abstract

The main objective of Tinnitus Retraining Therapy (TRT) is habituation of activation of the autonomic nervous system, evoked by signals present in the auditory pathways. Sound therapy aims at decreasing the strength of these signals. The same systems in the brain are involved in tinnitus and decreased sound tolerance, and the same basic neurophysiological mechanisms are utilised for decreasing the tinnitusrelated neuronal activity and, in case of hyperacusis, abnormally enhanced activity induced by external sounds. The similarity of TRT treatment between tinnitus and misophonia is even closer, as in both situations the goal is to achieve extinction of functional connections between the auditory and the limbic and autonomic nervous systems. The increased gain within the auditory pathways that are presumably responsible for hyperacusis could enhance the tinnitus signal, thus it is possible to expect coexistence of tinnitus and hyperacusis, and the predisposition of hyperacusis patients to develop tinnitus. As such, for some patients tinnitus and hyperacusis may be considered the double manifestation of the same internal phenomenon.