Effectiveness of high-frequency repetitive transcranial magnetic stimulation in patients with depression and Parkinson's disease: a meta-analysis of randomized, controlled clinical trials

Aim: This meta-analysis aimed to assess the effect of high-frequency repetitive transcranial magnetic stimulation (HF-rTMS) for the treatment of depression in patients with Parkinson's disease (PD). Methods: The design was a meta-analysis of randomized controlled trials (RCTs). The participants were patients with PD who suffered from depression. The interventions were HF-rTMS alone or in combination with other treatments compared with sham-rTMS, placebo, and anti-depressant treatments. The primary outcome measure was changes in depressive symptoms, defined as the mean change in the total depression score. The secondary outcome was changes in motor symptoms, defined by Unified Parkinson's Disease Rating Scale part III scores, and the acceptability, defined as the risk of all-cause discontinuation. These were expressed as mean differences (MDs), standardized mean differences (SMDs), or risk ratios (RRs) with 95% confidence intervals (CIs). Results: We identified nine suitable trials, with data from 332 participants. For the patients with depression in PD, HF-rTMS was not better than sham-rTMS (SMD=-0.33, 95% CI -0.83 to 0.17) or selective serotonin re-uptake inhibitors (SSRIs) (SMD = 0.07, 95% CI -0.52 to 0.18) for the treatment of depressive symptoms. However, the motor benefits after treatment with HF-rTMS might be better than sham-rTMS (MD=-2.80, 95% CI -5.45 to -0.15) and SSRIs (MD=-2.70, 95% CI -4.51 to -0.90). Conclusion: This meta-analysis provides some evidence that in patients with PD with depression, HF-rTMS may lead to improvement in motor function but not in depression compared with sham-rTMS or SSRIs.