Multisite transcranial Random Noise Stimulation (tRNS) modulates the distress network activity and oscillatory powers in subjects with chronic tinnitus

Abstract

Tinnitus is a common disorder in which auditory and non-auditory areas are involved as a network. Therefore, the multisite protocol of brain stimulation (tRNS) seems effective in relieving tinnitus symptoms. This study aimed to verify the modulatory effects of multisite tRNS on the tinnitus network. Thirty-two tinnitus-suffering patients received two consecutive sessions of tRNS (SHAM+ REAL) applied over the T3, T4 (the auditory cortex group) and F4, FP1 followed by T3, T4 (the multisite group). A 3-min resting-state EEG was recorded before and immediately after each session. After the multisite-tRNS real session, there was a significantly increased power in the alpha-1 band at the auditory and prefrontal cortex accompanied by decreased power in the delta and beta-2 bands in the prefrontal cortex. Standardized low-resolution brain electromagnetic tomography (sLORETA) showed a significant decrease in beta-2 activity in the prefrontal cortex, anterior cingulate cortex, and the parahippocampus and decreased alpha connectivity between the right prefrontal cortex and the left auditory cortex. No significant effects were noticed for the sham session. This study showed that tRNS has modulatory effects on the electrical activity of the brain and that targeting prefrontal and auditory areas in sequence could modulate the distress network and multiple hubs in the tinnitus network.