Abstract
Background
Cognitive decline is one of the greatest concerns for patients with Parkinson’s disease (PD) and their care partners. Repetitive transcranial magnetic stimulation (rTMS) is a nonpharmacological treatment option used to improve cognitive function in PD, but its efficacy is unclear. We performed a meta-analysis to determine whether rTMS improves cognition in PD patients.
Methods
Eligibility criteria (PICOS) were as follows: (1) ‘P’: The patients participating were diagnosed with idiopathic PD; (2) ‘I’: Intervention using rTMS; (3) ‘C’: Sham stimulation as control; (4) ‘O’: The outcome of the study included cognitive evaluations; (5) ‘S’: The study adopted randomized controlled design. The standardized mean difference (SMD) of change of score was applied to measure efficacy, and we used Version 2 of the Cochrane tool to assess risk of bias.
Results
Twelve studies met the inclusion criteria. Compared with sham-controlled group, the pooled result showed a non-significant short-term effect of rTMS on global cognition (SMD: −0.15, 95% CI: −0.59 to 0.29, I2 = 36.7%), executive function (SMD: 0.03, 95% CI: −0.21 to 0.26, I2 = 0.0%), and attention and working memory (SMD: 0.05, 95% CI: −0.25 to 0.35, I2 = 0.0%). Long-term outcomes were either shown to be statistically nonsignificant.
Conclusions
Based on a limited number of studies, rTMS fails to improve cognition in PD. We call for additional high-quality randomized controlled trials with adequate sample sizes to determine the efficacy of rTMS.
Acknowledgments
We would like to appreciate the statistical instructions given by professor He Li from the statistic department of Guangdong Provincial People's Hospital, and we also thank AiMi Academic Services (www.aimieditor.com) for English language editing and review services.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Author’s contribution
KN and LJW designed the whole study. PKH searched the studies. PKH and JNC selected the studies. PKH, LMW and YHZ analyzed the data, PKH, LMW, YYG, QHX and YHQ prepared figures and drafted the article. PKH and LMW undertook the statistical analysis. PKH, HMC, YL, ZHH, KN, JHZ and LJW participated in the interpretation of data. PKH and LJW wrote the manuscript. PKH, SJF and GXM revised the manuscript. All authors read and approved the final manuscript.