Tinnitus and Hearing Center of Arizona - Audiology, Tinnitus, Oticon, Phonak, Resound Hearing Aids Tempe. Formerly Tri-City Audiology Tempe.
Tinnitus Retraining Therapy (TRT) is a method with which we seek to treat tinnitus and most, if not all of its negative consequences. Tinnitus becomes a problem when it affects our quality of life on any level. Tinnitus is often the result of injury to the inner ear, such as outer hair cell damage caused by excessive noise exposure. Acoustic trauma damages hair cells in the cochlea (organ of hearing) and corresponding neurons in the acoustic nerve and dorsal cochlear nucleus (DCN). The DCN is the most important brainstem region for relaying auditory signals to the brain. Researchers believe phantom sounds heard by tinnitus sufferers are generated here. The DCN receives auditory signals from the ear, signals related to eye movements, and signals from muscle position sensors in the face, head, neck, trunk, arms, tongue, and the temporomandibular joint.
In chronic tinnitus, the initial tinnitus signal is recognized and evaluated as important by the brain because of its continuous presence. Between the ear and the brain are 2 million nerve cells that form a neuronal network, capable of sophisticated pattern recognition, enhancement, and suppression of auditory signals. The neuronal networks become highly tuned to the tinnitus pattern so that the auditory system can easily recognize it even in the presence of other signals. This is the same as our ability to hear the sound of our own name even in high levels of competing background noise. Signals that are considered highly significant to the brain are new signals, those that are associated with emotional or unpleasant situations, related to survival, and those that are a threat to health or life.
If the first experience of tinnitus evokes a high level of annoyance or anxiety or is associated with something unpleasant or occurs during a period of stress or anxiety, it is classified as important and this will result in an enhancement of activity in the limbic system and/or autonomic nervous system. This prepares a person for a defensive action. These systems remain on an increased level of activity for a prolonged period of time. The tinnitus signal is extensively monitored which further enhances its importance. The neuronal networks become even more highly tuned to the tinnitus signal. As this cycle continues, over-activation of the limbic and autonomic nervous systems also interferes with our ability to achieve deep stages of sleep (REM Stage) and prevents our brain from rejuvenating properly. Ultimately this can lead to depression and a host of other problems.
TRT is possible because it takes advantage of the plasticity or re-trainability of the nervous system. This plasticity allows for the eventual habituation of tinnitus, similar to how the brain habituates neutral external sounds such as fan noise created by a refrigerator. Tinnitus can be habituated through removal of any perceived negative associations, thereby contributing to limited activation of the limbic and autonomic nervous systems. Extensive cognitive behavior centered counseling is necessary to help remove these negative associations. Sound therapy is the additional essential component to TRT that contributes to habituation. Low level, soothing background sounds create competing neuronal signals that balance out the perceived strength of the tinnitus signal. This alters our detection of the tinnitus signal and disrupts the compensatory gain in the auditory pathways. It also serves to lower activation of the limbic and autonomic nervous systems. The specific protocol of sound therapy depends on a variety of factors, including the significance of hyperacusis, misophonia, hearing loss, and tinnitus. Based on these factors, it is possible to distinguish five major categories of treatment. For any case, however, the sound levels that are used are so low that they do not interfere with conversation, work, school, use of the telephone, etc. TRT is one of the most popular treatment options among tinnitus centers in the United States and Europe.