Effect of rTMS on Parkinson's Cognitive Function: A Systematic Review and Meta-analysis

Abstract

Background: To evaluate the effects and optimal parameters of repetitive transcranial magnetic stimulation (rTMS) on cognition function of Parkinson's disease (PD) patients and to estimate which cognitive function may obtain more benefits from rTMS. Method: The articles dealing with rTMS on cognition of PD patients were retrieved from the databases until April 2019. Two researchers selected research papers, evaluated their quality, extracted data, and cross-checked them according to the inclusion and exclusion criteria. The standardized mean differences (SMDs) with 95 % confidence interval (CI) of cognitive outcome for different parameters, scales, and cognitive functions were estimated. Results: Fourteen studies involving 173 subjects were included in the study. A significant effect size was observed with the mini-mental state examination (MMSE) for the global cognitive outcome based on the evidence of four published articles. Further subtests for different cognitive domains demonstrated prominent effect for the executive function. The significant effect sizes for executive function were found with multiple sessions of high-frequency rTMS over frontal cortex, especially over dorsolateral prefrontal cortex (DLPFC). All of the other cognitive domains including memory, attention, and language ability did not obtain significant effects. Conclusions: Multiple sessions of high-requency rTMS over the DLPFC may have positive effect on executive function in PD patients. Further well designed studies with large sample sizes are needed to verify our results and ascertain the long-term effects of rTMS.

Effects of repetitive transcranial magnetic stimulation on gait disorders and cognitive dysfunction in Parkinson's disease: A systematic review with meta‐analysis

“…In line with a previous meta‐analysis by Jiang et al. (2020), our overall pooled results suggest that rTMS has a positive impact on cognitive function in PD. Jiang et al.…”

“…Jiang et al. (2020) used the mini‐mental state examination to observe the effect of rTMS on global cognitive function, whereas we used the MOCA outcome. On the other hand, the meta‐analysis by Jiang et al.…”

“…On the other hand, the meta‐analysis by Jiang et al. (2020) included 11 studies and used a variety of outcomes such as the executive function index and FAB. To assess the effect of rTMS on executive function, we only included three studies in which FAB was selected as the outcome.…”

Efficacy of repetitive transcranial magnetic stimulation in Parkinson's disease: A systematic review and meta-analysis of randomised controlled trials

“…In this study, we tried to pool RCTs to analyse the efficacy of rTMS intervention on cognitive function, but the number of RCTs with suitable cognition scales before and after rTMS intervention was insufficient. Some reviews and meta-analyses considered that rTMS intervention may have limited but positive effects on executive function 60 or working memory. 61 However, Lawrence et al (2017) considered the results were insufficient to determine whether rTMS intervention was effective, but the authors could not exclude the ceiling effect of the potential therapeutic effect of the intervention because the number of included studies with rTMS intervention was insufficient.…”

“…Therefore, we did not further analyse the change in various cognitive aspects as other reviews and metaanalyses. 60,61 Meanwhile, we acknowledge that the insufficient numbers of studies included in depressive groups may cause inconsistency of results among subgroups. Besides, we agreed that analysis separating the patients with PD as young vs early stage is beneficial.…”