Treatment of Tinnitus With Transcranial Magnetic Stimulation

Tinnitus is the perception of sound in the absence of corresponding external sound. Tinnitus affects approximately 10-15 % of the population. The prevalence increases with age and it is estimated that more than 20 % of the older people have tinnitus. Approximately 10-15 % of tinnitus patients have clinically relevant, disabling tinnitus causing for example anxiety, depression and sleep disturbances. The treatment of chronic tinnitus is difficult and most therapies focus on alleviating the condition rather than treating the cause. Pathophysiology of tinnitus still remains incompletely understood. Functional brain imaging data in tinnitus patients and animal models suggest that tinnitus is associated with increased neuronal activity, increased synchronicity, and functional reorganization within the auditory cortex either uni- or bilaterally, but there are also functional alterations in brain areas outside the auditory system. Transcranial magnetic stimulation (TMS) is a neuromodulation technique based on the principle of electromagnetic induction of an electric field in the brain by means of magnetic pulses given to the scalp. TMS is a non-invasive, painless, and safe method for modulation of cortical activity. TMS pulses given at low frequencies (≤ 1 Hz) have been shown to decrease cortical excitability both in experimental settings and humans, which forms the basis for using low frequency rTMS to treat chronic tinnitus patients, in whom hyperactivity of the auditory cortex has been observed in functional brain imaging studies