Influence of Treatment Duration and Stimulation Frequency on rTMS in Chronic Tinnitus

Tinnitus is the phantom auditory perception of sound in the absence of an external or internal acoustic stimulus. It is a frequent problem which can interfere significantly with the ability to lead a normal life. Tinnitus has been shown to be generated in the brain, as a result of functional reorganization of auditory and non-auditory neural pathways. Low-frequency repetitive transcranial magnetic stimulation (rTMS) applied to the temporoparietal areas has been investigated for the treatment of tinnitus based on the rationale to reduce increased activity of the auditory system. Furthermore, high-frequency stimulation of the left frontal cortex was added to this standard treatment based on rTMS studies in affective disorders and the association of tinnitus distress with depressivity. Thus, high-frequency stimulation of the left prefrontal cortex and low-frequency stimulation of bilateral temporoparietal cortex was introduced as new treatment scheme in chronic tinnitus (multisite standard). Additionally, there is also evidence that high-frequency stimulation of the temporoparietal cortex is effective in chronic tinnitus. Furthermore, standard treatment in chronic tinnitus is two weeks (ten treatment days) which is shorter than the standard in rTMS in affective disorders. Thus, the aim of the present trial is to investigate the influence of high-frequency stimulation of the temporoparietal cortex and of increasing the number of treatment days. Patients receive two weeks of treatment (prefrontal high-frequency and bilateral low-frequency rTMS vs. prefrontal high-frequency and bilateral high-frequency rTMS). After two weeks of treatment they can decide if they want to quit the treatment or if they want to proceed with the treatment for another two weeks.