Article Text
Abstract
Objectives To compare cognitive effects and acceptability of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) in patients with Alzheimer’s disease (AD) or mild cognitive impairment (MCI), and to determine whether cognitive training (CT) during rTMS or tDCS provides additional benefits.
Methods Electronic search of PubMed, Medline, Embase, the Cochrane Library and PsycINFO up to 5 March 2020. We enrolled double-blind, randomised controlled trials (RCTs). The primary outcomes were acceptability and pre–post treatment changes in general cognition measured by Mini-Mental State Examination, and the secondary outcomes were memory function, verbal fluency, working memory and executive function. Durability of cognitive benefits (1, 2 and ≥3 months) after brain stimulation was examined.
Results We included 27 RCTs (n=1070), and the treatment components included high-frequency rTMS (HFrTMS) and low-frequency rTMS, anodal tDCS (atDCS) and cathodal tDCS (ctDCS), CT, sham CT and sham brain stimulation. Risk of bias of evidence in each domain was low (range: 0%–11.1%). HFrTMS (1.08, 9, 0.35–1.80) and atDCS (0.56, 0.03–1.09) had short-term positive effects on general cognition. CT might be associated with negative effects on general cognition (−0.79, –2.06 to 0.48) during rTMS or tDCS. At 1-month follow-up, HFrTMS (1.65, 0.77–2.54) and ctDCS (2.57, 0.20–4.95) exhibited larger therapeutic responses. Separate analysis of populations with pure AD and MCI revealed positive effects only in individuals with AD. rTMS and tDCS were well tolerated.
Conclusions HFrTMS is more effective than atDCS for improving global cognition, and patients with AD may have better responses to rTMS and tDCS than MCI.
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Footnotes
C-SC and C-TL contributed equally.
Contributors C-SC and ARB contributed equally as first authors, independently screened the studies, and extracted the relevant information from the manuscripts and drafted the current manuscript. Y-KT and TT, the specialists of statistics, took the responsibility of supervising the whole statistical process and technical support. T-CY and C-KT evaluated the risk of bias. F-CY, P-TT, BS, AFC, TkR, T-YC, D-JL, C-WH, Y-CW and C-LY contributed in concept formation, study design, methodology support and manuscript revision. C-SL and C-TL, the corresponding authors, took the responsibility of data deposit, collection of all information from the other authors and submitting the current manuscript.
Funding This study was sponsored by grants from Taipei Veterans General Hospital (V108D44-003-MY3-1) and Kaohsiung Veterans General Hospital (VGHKS 109-070), and the Ministry of Science and Technology (MOST 106-2314-B-075-034 -MY3; 108-2321-B-075-004-MY2). In addition, this work was supported by the Brain Research Center (108BRC-B502), National Yang-Ming University from The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education (MOE) in Taiwan.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request from corresponding author (C-SL).
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