Moderate therapeutic efficacy of PET-navigated repetitive transcranial magnetic stimulation against chronic tinnitus: a randomized, controlled pilot study

Background Tinnitus has been shown to respond to modulations of cortical activity by highand lowfrequency repetitive transcranial magnetic stimulation (rTMS). Objective To determine the tinnitus-attenuating effects of a two week-daily regimen of rTMS, navigated to the maximum of tinnitus-related increase in regional cerebral blood flow (rCBF). Methods Six patients with chronic tinnitus were enrolled in this sham-controlled cross-over study and treated with 2x2 weeks of suprathreshold 1 Hz rTMS (30 min) applied to the region with maximal tinnitus-related increase of rCBF delineated by functional imaging with [O]H2O PET and a control area. Tinnitus-related distress was assessed before and after each treatment and 2 weeks after the end of the 4 weeks course of stimulation using a validated tinnitus questionnaire (TQ). Additional self-assessment scores of tinnitus change, loudness and annoyance were obtained. Results In 5 of 6 subjects, rTMS induced greater reduction of the TQ score than sham stimulation. In two patients, all parameters measured (tinnitus change score, tinnitus loudness, tinnitus annoyance) showed unequivocal improvement. At group level, the degree of response in the TQ score was corrrelated with tinnitus-associated activation of the anterior cingulate cortex (ACC). Two weeks after the final stimulation, tinnitus had returned to baseline in all patients but one. Conclusion Tinnitus can be attenuated by low-frequency rTMS navigated to each individual's maximum of tinnitus-related, cortical hyperactivity. The effects are only moderate, interindividual responsiveness varies and the attenuation seems to wear off within two weeks after the last stimulation session. Of note, tinnitus-related ACC activation appears to predict the response to rTMS treatment. 2 on 23 August 2006 jnnp.bmjjournals.com Downloaded from