Repetitive transcranial magnetic stimulation (rTMS) fails to improve cognition in patients with parkinson’s disease: a Meta-analysis of randomized controlled trials

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.

Keywords:

• Parkinson’s disease
• repetitive transcranial magnetic stimulation
• cognition
• meta-analysis
• randomized controlled trial

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.

Additional information

Funding

This work was supported by grants of National Key R&D Program of China (No. 2017YFC1310200), National Natural Science Foundation of China (No.81671275), Guangdong Natural Science Foundation (No.2016A030310327, 2018A030313427), Key Program of Natural Science Foundation of Guangdong Province, China (No. 2017B030311015), Guangzhou Municipal People's Livelihood Science and Technology Project (No.201803010085), The Fundamental Research Funds for the Central Universities (2018MS27), Medical Science and Technology Research Fund of Guangdong Province (A2018137).