title: Repetitive Transcranial Magnetic Stimulation as an Alternative Therapy for Cognitive Impairment in Alzheimer's Disease: A Meta-Analysis.
abstract: BACKGROUND
  Recent studies have indicated that repetitive transcranial magnetic stimulation (rTMS) could improve cognitive function in people with Alzheimer's disease (AD). Yet the results are inconclusive.
  
  
  OBJECTIVE
  This meta-analysis aimed to evaluate recent rTMS studies conducted in mild to moderate AD patients.
  
  
  METHODS
  PubMed, Embase, MEDLINE databases and Science Direct were searched for studies of rTMS treatment on AD patients with cognitive impairment published before February 2015. The relevant primary outcomes of cognition were extracted from those included studies. A crude standardized mean difference (SMD) with 95% confidence interval (CI) was calculated by using random effect models.
  
  
  RESULTS
  Seven studies with a total of 94 mild to moderate AD patients were included in this meta-analysis. A significant overall rTMS treatment effect on cognition was found for all AD patients (p = 0.0008, SMD = 1.00, 95% CI = 0.41-1.58). Stratification analysis showed that this effect is stimulation frequency- and hemisphere-dependent. High frequency stimulation (>1.0 Hz) (p <  0.05) but not low frequency stimulation (≤1.0 Hz) (p >  0.05) was significantly effective in improving the cognition of AD patients. Further, rTMS stimulation on right dorsolateral prefrontal cortex (DLPFC) and bilateral DLPFC (p <  0.05), but not on the left DLPFC (p >  0.05) was significantly effective in improving cognitive function of AD patients. A significant effect was observed in the rTMS subgroup (p <  0.05), rather than in the rTMS+drug subgroup (p >  0.05).
  
  
  CONCLUSIONS
  This meta-analysis supports that high frequency rTMS stimulation on right- or bilateral-DLPFC has significant therapeutic effect on cognitive function in patients with mild to moderate AD. Due to small number of studies included, more well-controlled rTMS studies should be evaluated in AD patients in the future.
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Liao
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Li
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.
authors.forename: Anguo
authors.initials: A
authors.lastname: Wang
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.
authors.forename: Shenggang
authors.initials: S
authors.lastname: Feng
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Tang
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.|Luzhou Medical College, Luzhou, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Lotus Biotech.com LLC, Rockville, Maryland, USA.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Xing
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.
authors.forename: Morgan A
authors.initials: MA
authors.lastname: McClure
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.
authors.forename: Huaping
authors.initials: H
authors.lastname: Chen
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.
authors.forename: Bin
authors.initials: B
authors.lastname: He
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Liu
authors.affiliation: Imaging Institute of Rehabilitation and Development of Brain Function, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.|Department of Neurology, North Sichuan Medical University Nanchong Central Hospital, Nanchong, China.|Peking University Third Hospital, Beijing, China.
authors.forename: Qiwen
authors.initials: Q
authors.lastname: Mu
mesh_terms: D000544:Alzheimer Disease / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D003072:Cognition Disorders / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D050781:Transcranial Magnetic Stimulation / Q000379:methods
keywords: Alzheimer’s disease; meta-analysis; mild to moderate cognitive impairment; repetitive transcranial magnetic stimulation