25 years of tinnitus retraining therapy.

This year marks 25 years of tinnitus retraining therapy (TRT), the approach that aims to eliminate tinnitus as a problem by extinguishing functional connections between the auditory and the limbic and autonomic nervous systems to achieve habituation of tinnitus-evoked reactions and subsequently habituation of perception. TRT addresses directly decreased sound tolerance (DST) as well as tinnitus. TRT consists of counseling and sound therapy, both based on the neurophysiological model of tinnitus. The main goal of retraining counseling is to reclassify tinnitus into the category of a neutral stimulus, while the main goal of sound therapy is to decrease the strength of tinnitus-related neuronal activity. A unique aspect of TRT is that because treatment is aimed to work above the tinnitus source, and at connections linking the auditory and other systems in the brain, the etiology of tinnitus is irrelevant. Any type of tinnitus, as well as somatosounds, can be successfully treated by TRT. Over 100 publications can be found on Medline when using "tinnitus retraining therapy" as a search term. The majority of these publications indicate TRT offers significant help for about 80 % of patients. A randomized clinical trial showing the effectiveness of TRT has been published and another large study is in progress. The principles of the neurophysiological model of tinnitus, and consequently TRT, have not changed in over 25 years of use, but a number of changes have been introduced in TRT implementation. These changes include the recognition of the importance of conditioned reflexes and the dominant role of the subconscious pathways; the introduction of the concept of misophonia (i.e., negative reactions to specific patterns of sound) and the implementation of specific protocols for its treatment; greater emphasis on the concurrent treatment of tinnitus, hyperacusis, misophonia, and hearing loss; extensive modification of counseling; and refinements in sound therapy. The effectiveness of TRT has increased significantly during the past 25 years, presumably due to changes incorporated in its implementation. The main improvement has been to shorten the average time until seeing clear improvement from 1 year to 1 month, with a statistically significant improvement seen at, and after, 3 months. Furthermore, there is a higher effectiveness and a shorter treatment time for DST and an increased extent of help for hearing loss.