Tuning the tinnitus percept by modification of synchronous brain activity.

PURPOSE Tinnitus, the perception of sound without the presence of a physical stimulus, provides the opportunity to study neural codes of percepts without simultaneous processing of stimuli. Previously, we have found that tinnitus is associated with enhanced delta- and reduced tau-power in temporal brain regions. By operantly modifying corresponding aspects of spontaneous EEG activity, the aim of the present study was to corroborate the assumption that tinnitus should be reduced if patterns of ongoing synchronous brain activity are normalised. METHODS In response to different variants of neurofeedback, a total of twenty-one patients produced significant changes in EEG frequency bands. RESULTS Simultaneous alteration of both frequency bands was strongly related to changes in tinnitus intensity matched before and after the intervention (r=-0.74). In those two patients with the greatest modulatory success, the tinnitus sensation resided completely in response to the treatment. Comparing the neurofeedback-treated patients with a group of patients trained with a frequency discrimination task (n=27), the tinnitus relief in the neurofeedback group was significantly stronger. CONCLUSIONS This study supports the notion that altered patterns of intrinsic ongoing brain activity lead to phantom percepts and offer new routes to the treatment of tinnitus.