Objective  To observe the efficacy and safety of repetitive transcranial magnetic stimulation (rTMS) on refractory tinnitus and the differences of resting-state functional magnetic resonance imaging (rs-fMRI) imaging between before and after treatment, and to explore the possible central mechanism of rTMS regulation of tinnitus.

Methods  Thirty-seven patients with refractory tinnitus admitted in Affiliated Hospital of North Sichuan Medical College from September 2022 to February 2023 were selected and were divided into experimental group (n=20) and control group (n=17). The experimental group was given true rTMS treatment, and the control group was given sham stimulation with the same parameters. Tinnitus handicap inventory (THI) score, tinnitus loudness visual analogue scale (VAS) score and rs-fMRI scan were performed before and after treatment. Regional homogeneity (ReHo) was calculated after scanning, and the different brain regions were selected as the area of interest (ROI) and the whole brain functional connection (FC) was performed.

Results  There were no significant differences in age, gender, education level, tinnitus side, course of disease, hearing level, self-rating depression scale, self-rating anxiety scale the experimental group and control group. There were no significant differences in THI and VAS scores between the two groups before treatment; the THI and VAS scores in the experimental group decreased after 2 weeks of rTMS treatment (P＜0.001), while there was no significant difference in the two scores in the control group before and after treatment. Only 3 patients in the experimental group experienced left facial muscle tremor or transient mild scalp pain during treatment, without other serious side effects. The ReHo of the left cerebellar area 9 increased in the experimental group after rTMS (P＜0.005); the ReHo values in the right inferior temporal gyrus, left posterior central gyrus and left anterior central gyrus increased in the control group after intervention (P＜0.005). The FCs between the right inferior temporal gyrus and the left orbital inferior frontal gyrus, the left anterior cingulate gyrus increased in the experimental group (P＜0.005), and FC between the right inferior temporal gyrus and the left superior marginal gyrus decreased (P＜0.005). The FCs between the right cuneus and the left fusiform gyrus, right superior occipital gyrus decreased in the experimental group after rTMS (P＜0.005). The FC between the right cuneus and the left fusiform gyrus increased in the control group after intervention (P＜0.005),while other FCs remained unchanged.

Conclusions  rTMS has a certain therapeutic effect on refractory tinnitus with higher safety; regulation of auditory brain network and related non-auditory brain network may be one of the central mechanisms of rTMS treating refractory tinnitus.