Abstract: Five trials comprising of 233 participants met our inclusion criteria. Each study described the use of a different rTMS device that delivered different waveforms at different frequencies. All five trials were relatively small studies but generally they demonstrated a low risk of bias. When considering the impact of tinnitus on patients' quality of life, the results of only one study demonstrated a statistically significant improvement in Tinnitus Handicap Inventory (THI) scores at four months follow-up (defined as a 'partial improvement' by the study authors (THI reduction of 21% to 80%)) when low-frequency rTMS was compared with a sham control treatment. However, no statistically significant improvement was demonstrated by another two studies that considered rTMS at the same frequency. Furthermore, this single positive finding should be taken in the context of the many different variables which were recorded at many different points in time by the study authors. In accordance with our pre-specified subgroup analysis we extracted the data from one study to consider the differential effectiveness between 'lower' low-frequency rTMS (1 Hz) and 'higher' low-frequency rTMS (10 Hz, 25 Hz). In doing this we were able to demonstrate a statistically significant difference between rTMS employing a frequency of 1 Hz and the sham group when considering tinnitus severity and disability after four months follow-up ('partial' improvement). However, no statistically significant difference was demonstrated between 10 Hz and 25 Hz rTMS, and the sham control group, when considering the severity and disability of tinnitus at four months follow-up. When considering tinnitus loudness in patients undergoing rTMS we were able to demonstrate a statistically significant reduction in tinnitus loudness when the results of two studies were pooled (risk ratio 4.17, 95% confidence interval 1.30 to 13.40). However, this finding was based on two small trials and consequently the confidence interval was particularly wide. No serious adverse effects were reported in any of the trials. There is very limited support for the use of low-frequency rTMS for the treatment of patients with tinnitus. When considering the impact of tinnitus on patients' quality of life, support is from a single study with a low risk of bias based on a single outcome measure at a single point in time. When considering the impact on tinnitus loudness, this is based on the analysis of pooled data with a large confidence interval. Studies suggest that rTMS is a safe treatment for tinnitus in the short-term, however there were insufficient data to provide any support for the safety of this treatment in the long-term. More prospective, randomised, placebo-controlled, double-blind studies with large sample sizes are needed to confirm the effectiveness of rTMS for tinnitus patients. Uniform, validated, tinnitus-specific questionnaires and measurement scales should be used in future studies.

Plain-language summary: Our search for studies retrieved 283 articles. Of these, five trials comprising 233 tinnitus patients met our inclusion criteria and were included in the review. The first study considered the use of 'complex waveform rTMS', the second looked at the use of high-frequency rTMS, and the other three studies considered the use of low-frequency rTMS. We found that the use of low-frequency rTMS resulted in 'partial improvement' in tinnitus severity and disability in one study, however these results were not replicated in two other studies that considered rTMS at the same frequency. Furthermore, this single positive finding should be taken in the context of the many different variables which were recorded at many different points in time by the study authors. We were able to demonstrate an improvement in tinnitus loudness in patients undergoing rTMS when we combined the results of two other studies. rTMS is a safe treatment for patients with tinnitus in the short-term, however no data were available to verify safety in the long-term.