RESUMO
Recent studies have indicated that the pathophysiological basis for tinnitus may be abnormal activity in the auditory areas of the brain rather than aberrant activity in the periphery. Tinnitus-related activity leads to changes in tonotopic representation in auditory cortex. However, such reorganization can be reversed through training-induced changes in the response pattern of cortical neurons. We address this problem by using customized sounds that reproduce the subjective experience to reduce overactive auditory circuits. The results of two preliminary studies indicate that customized sound therapy (CST*) aimed at this central dysfunction reduces tinnitus quickly and safely. Participants described immediate relief, showed changes on the Tinnitus Handicap Questionnaire, and reported changes in hearing threshold within 3 weeks. We also saw changes in the intensity dependence of the auditory N100 in tinnitus patients, supporting the idea that tinnitus reflects a reorganization of tonotopic maps in the auditory cortex. The main correlate of this reorganization was the enhanced contrast between responses to the perceived tinnitus pitch and tones approximately one octave lower. After 3 weeks of CST, the intensity dependence to the tinnitus pitch decreased, making these responses more similar to those from normal subjects responding to tones in the same frequency.