Non-invasive brain stimulation for treating psychiatric symptoms in Parkinson's disease: A systematic review and...

Non-invasive brain stimulation (NIBS), especially repetitive transcranial magnetic stimulation (rTMS), is a promising therapeutic tool for managing the psychiatric symptoms of Parkinson's disease (PD). This meta-analysis aims to assess the effect of NIBS on psychiatric symptoms in patients with PD.

Several electronic databases were systematically searched for relevant literature from inception to October 18, 2021. The therapeutic effects of NIBS were evaluated using a random-effects meta-analysis based on the standard mean difference (SMD) and multivariable-adjusted effect estimates and subgroup analyses. Publication bias and sensitivity analyses were used to explore the sources of heterogeneity.

Finally, 57 and 15 studies with 4,010 participants were obtained from the meta-analysis and systematic review, respectively. Significant differences were found between NIBS and sham-stimulation/placebo participants for depression (SMD = -0.75, 95 % confidence interval [CI]: -0.99 to -0.50, I² = 79 %), and rTMS combined with antidepressant therapy and antidepressant alone for depression (SMD = -0.98, 95 % CI: -1.37 to -0.59, I² = 87 %) and anxiety (SMD = -1.46, 95 % CI: -2.44 to -0.48, I² = 95 %). Meanwhile, lower risks were observed for post-treatment compared with pre-treatment for depression (relative risk [RR] = 0.66, 95 % CI: 0.57-0.76, I² = 96 %) and anxiety (RR = 0.66, 95 % CI: 0.60-0.73, I² = 67 %).

NIBS can be considered an effective non-pharmacological option for treating PD depression; moreover, rTMS combined with antidepressants was demonstrated to be a useful tool against depression and anxiety in PD.