P056 Daily transcranial random noise stimulation of the temporal cortex in chronic tinnitus

Abstract

Question Hyper-activity and hyper-synchronicity of auditory areas are involved in the pathology of chronic tinnitus. Transcranial random noise stimulation (tRNS) – a non-invasive electric brain stimulation method – was recently shown to be able to reduce tinnitus loudness and distress after single sessions in big samples and after daily sessions of tRNS in one small sample. For the first time, we investigate the tolerability and efficacy of daily sessions of tRNS in a bigger sample of chronic tinnitus. Methods In this one-arm study, thirty patients receive high-frequency tRNS of the left and right temporal cortex consisting of ten daily sessions. Study visits are baseline (treatment day 1), week 2 (treatment day 10), week 4 and 12 (two and ten weeks after treatment, respectively). Results Compatibility: Six patients perceived temporal increases in tinnitus loudness (two drop-outs) and two patients report headaches (one drop-out). One patient did not finish the treatment due to personal reasons. Typical side effects were mild to moderate tingling (87%), tiredness (67%), and itching (47%). There was no evidence for cognitive effects of the stimulation. Primary outcome: There were eight treatment responders for the rTMS and the tRNS trial with only two of them responding in the rTMS as well as in the tRNS treatment. Secondary outcomes: TQ, MDI, numeric ratings, and quality of life did not show significant effects of time or time by treatment except for the numeric rating unpleasantness (decrease from week baseline to week 2) and the quality of life domain physical well-being (increase from week 4 to week 12. Conclusions Treatment of chronic tinnitus with high-frequency tRNS is easy applicable, showed tolerable side effects and efficacy in the same range as rTMS (31% for this sample), but resulted in temporal increases in tinnitus loudness in 20% of the cases (including two drop-outs). Notably, treatment response to rTMS did not predict treatment response to tRNS favoring individualized treatment with brain stimulation which can be realized by using single test sessions as recommendation for daily treatment. Specific changes in unpleasantness after tRNS in contrast to rTMS might be explainable by the stimulation of more medial temporal areas such as posterior insula or hippocampus (summation of electric currents in border regions of different types of tissues).