Effects of repetitive transcranial magnetic stimulation on cognitive function and recurrence of symptoms in individuals with bipolar disorder: a double-blind parallel randomized controlled trial

Background and objective: Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive nerve stimulation technique that has the potential to improve cognitive function. However, there have been few randomized controlled trials (RCTs) that evaluated the effectiveness of rTMS on cognitive function and the relapse in patients with bipolar disorder. Participants and methods: This double-blind parallel RCT will be conducted at The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), China. A total of 74 bipolar disorder patients will be recruited and randomly assigned to a trial group (n = 37) and control group (n = 37). Repetitive transcranial magnetic stimulation and sham repetitive transcranial magnetic stimulation will be applied over the left dorsolateral prefrontal cortex in the trial group and control group, respectively. This trial was designed on March 2, 2017 and was approved by the Ethics Committee of The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), China on April 25, 2017 (approval No. 2017022). Patient recruitment began on July 10, 2017 and will be finished in December 2020. The trial will be completed in December 2021. The protocol version is 1.0. Outcome measures: The primary outcome measure will be the difference between MATRICS Consensus Cognitive Battery scores at post-intervention and at baseline. The secondary outcome measures will be relapse of depressive and/or hypo/mania episode at a one-year follow-up. Discussion: This clinical trial will provide data regarding effectiveness in long-term cognitive function and relapse of mood episode following repetitive transcranial magnetic stimulation in patients with bipolar disorder. Trial registration: This trial had been registered in the ClinicalTrials.gov (identifier: NCT03207048) on July 2, 2017.