Are there neural connectivity changes associated with repetitive transcranial magnetic stimulation (rTMS) to the temporoparietal junction in patients with tinnitus?
Background: Tinnitus pathophysiology is not fully understood. Recent research has shifted to the idea that excessive spontaneous activity in the auditory cortex may explain the amount of bother experienced by tinnitus patients. rTMS uses a magnetic field to create an electric current within the brain that depolarizes axons and activates neural networks; repeated application has the potential to induce changes in neural connectivity.
Explore this issue:May 2016
Study design: Randomized, double blind, controlled clinical trial of 30 patients with subjective, nonpulsatile tinnitus for six months’ duration or longer and a score of ≥ 36 on the Tinnitus Handicap Inventory.
Setting: Department of Otolaryngology–Head and Neck Surgery, Washington University in St. Louis School of Medicine, Mo.
Synopsis: Participants received five treatment sessions per week for two or four consecutive weeks. There were no differences in baseline age or hearing between the active and sham groups, and neither active treatment, either for two or four weeks, was found to be more effective than sham treatment for symptom reduction according to THI assessments. No serious adverse events were reported. Although the connectivity with each seed region identified an appropriate resting state network, there were no differences in connectivity between active and sham groups using any of the seed regions. There were also no significant differences between active and sham groups in post-treatment connectivity using any of these seed regions. No significant differences were found on pairwise connectivity among seed regions covering the whole brain. Regardless of group membership, pairwise functional neural connectivity with baseline THI, change in THI, baseline depression, and change in depression were correlated, but none were statistically significant. Limitations included the possibility that the sampling did not represent the general tinnitus population.
Bottom line: The analysis did not identify any changes in neural connectivity following treatment in patients with bothersome tinnitus. Measures of neural connectivity may inform future work using rTMS to better understand the possible benefits of neural stimulation for tinnitus.
Citation: Roland LT, Peelle JE, Kallogjeri D, Nicklaus J, Piccirillo JF. The effect of noninvasive brain stimulation on neural connectivity in tinnitus: a randomized trial. Laryngoscope. 2016;126:1201-1206.