Effects of Repetitive Transcranial Magnetic Stimulation in Patients With Mild Cognitive Impairment: A Meta-Analysis of Randomized Controlled Trials

Abstract

Background: Mild cognitive impairment (MCI) is an intermediary state between normal aging and dementia. It has a high risk of progression in patients with Alzheimer's disease (AD). Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique used to improve cognitive deficits in patients with MCI and AD. Although previous meta-analyses included studies carried on patients with MCI and AD, few studies have analyzed patients with MCI independently. This meta-analysis aimed to evaluate the effects and safety of rTMS on cognition function in patients with MCI and factors that may influence such effects.Methods: Data used in this study were searched and screened from different databases, including PubMed, Web of Science, Embase, the Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), Chinese Technical Periodicals (VIP), Wanfang Database, and China BioMedical Literature Database (SinoMed). The retrieved studies were carefully reviewed, data were extracted, and the quality of data was assessed.Results: A total of 12 studies involving 329 patients with MCI were included in the present meta-analysis. The analyses results revealed that rTMS improved cognitive function [standardized mean difference (SMD) = 0.83, 95% confidence interval (CI) = 0.44–1.22, p = 0.0009] and memory function (SMD = 0.73, 95% CI = 0.48–0.97, p < 0.00001) in the MCI + rTMS active group when compared to the sham stimulation group. The showed that: (1) cognitive improvement was more pronounced under high-frequency rTMS stimulation of multiple sites, such as the bilateral dorsolateral prefrontal cortex and (2) more than 10 rTMS stimulation sessions produced higher improvement on cognition function in patients with MCI.Conclusions: This study shows that rTMS can improve cognitive function in patients with MCI, especially when applied at high frequency, multi-site, and for a prolonged period. However, further studies are required to validate these findings and explore more effective stimulation protocols and targets.Systematic Review Registration: [http://www.crd.york.ac.uk/PROSPERO/], identifier: CRD 42021238708.

Dual-targeted repetitive transcranial magnetic stimulation modulates brain functional network connectivity to improve cognition in mild cognitive impairment patients

“…Dual-targeted rTMS significantly improved overall cognitive function, including memory, executive, and attentional functions in MCI patients. This finding is consistent with previous studies reporting that rTMS improves cognitive function in MCI patients (Zhang, et al, 2021). Two locations of our stimulation affected the DMN, a network consisting of the PCC/PCu, medial prefrontal cortex, inferior parietal lobule, lateral temporal cortex, and hippocampal structures (Buckner, et al, 2008).…”

“…In a crossover trial of "prodromal AD," rTMS at the left PCu site significantly enhanced memory as assessed by the Rey auditory verbal learning delayed recall score; however, there was no significant change in other cognitive function scores (Koch, et al, 2018). A meta-analysis on improving cognitive function by rTMS indicated that high-frequency, multi-site, and longsession rTMS was more effective in enhancing MCI cognitive function (Zhang, et al, 2021). Based on the characteristics of altered brain networks in MCI cognitive impairment, prefrontal and parietal regions stimulation may have a better overall cognitive improvement effect (Badhwar, et al, 2017).…”

Resting state electroencephalography contributes to the detection of disease progression and prediction of repetitive transcranial magnetic stimulation modulations in patients with subjective cognitive decline

“…Human cognitive impairment has been associated with abnormal functional activity 46 . High frequency rTMS increases cortical excitability and has been shown to ameliorate cognitive performance in MCI and AD patients when applied over the left DLPFC 31,47,48 . rTMS therapy targeting the partial cortex could improve the posterior hippocampal connectivity by modulating the precuneus in SCD 49 .…”

Does repetitive transcranial magnetic stimulation improve cognitive function in age‐related neurodegenerative diseases? A systematic review and meta‐analysis

“…1 RTMS is widely used in research for promoting cognitive enhancement 2 is a promising intervention for cognitive impairment in people with Mild Cognitive Impairment and age-related neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD). [3][4][5][6] Therefore, this systematic review was required to establish the efficacy of this intervention and understand the optimal protocol to achieve cognitive effects. RTMS delivers pulses of magnetic stimulation to induce currents in localised regions of neurons in the cerebral cortex.…”