How can we suppress a tinnitus? Scientists have tried a number of solutions. One strategy has been to aggressively adapt hearing sensations in the frequency range of the tinnitus. This approach, still under intensive study, has been mildly successful. A second approach has been to mask the tinnitus with continuous noise, or to trained adaptive adjustments to noises in an attempt to teach the sufferer to control the loudness of the ongoing tinnitus. These crude noise stimulation/adaptation methods are probably the most widely applied therapeutic approaches, and are often helpful for the tinnitus sufferer. A third approach has been to magnetically (or directly electrically) stimulate the brain, either to directly suppress responses in the stimulus-generating cortical zone(s), or to excite plausible sources of cortico-cortical feedback that have been shown to suppress activity in these zones (\for example, to suppress the hearing of your own voice as you talk). A fourth, novel approach described by Professor Christov Pantev at the meeting engaged the patient in about 1 hour/day of active music listening, during which time the music was filtered to exclude stimulation in the tinnitus-frequency range. The goal was to progressively competitively weaken the tinnitus frequencies, by competitively advantaging other more-distant sound frequencies. Moderate, but quite consistent and persistent tinnitus suppression was recorded in these patients. Sixth, other scientists (including my own research group) has attempted to train individuals to make sharper distinctions about sounds in these non-tinnitus-frequency ranges. This seems to help some but not all patients. Similarly, some patients that have been engaged in active listening with our “Brain Fitness Program” have recorded strong tinnitus suppression; others have received little or no benefit from such ‘competitive listening’ training. Seventh, we have been studying the potential use of a ‘reverse (negative) conditioning (training)’ method to try to directly weaken the neurological representation of the offending sound. We do not yet know if this very promising approach will be successful. Eighth, a former doctoral student from my laboratory, Michael Kilgard, has been able to create a model of tinnitus in an animal (rat), then shown that it can be broken down (strongly cross-coupled neurons that appear to be generating the tinnitus can be weakened) by a particular form of electrical stimulus-assisted plasticity. If their strategy (being pursued by a small startup company, MicroTransponder, Inc.) can be applied in humans, it may provide the most effective method up to this time for suppressing a tinnitus.
http://merzenich.positscience.com/?p=239#comments
Because of the traumatic brain injuries suffered by our troops in combat, there's a lot of money flowing into tinnitus these days. Let's hope one of these strategies will pan out.
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