title: Transcranial direct current stimulation as a memory enhancer in patients with Alzheimer's disease: a randomized, placebo-controlled trial.
abstract: BACKGROUND
  The purpose of this study was to assess the efficacy of transcranial direct current stimulation (tDCS) on verbal memory function in patients with Alzheimer's disease.
  
  
  METHODS
  We conducted a randomized, placebo-controlled clinical trial in which tDCS was applied in six 30-minute sessions for 10 days. tDCS was delivered to the left temporal cortex with 2-mA intensity. A total of 25 patients with Alzheimer's disease were enrolled in the study. All of the patients were diagnosed according to National Institute of Neurological and Communicative Disorders and Stroke and Alzheimer's Disease and Related Disorders Association criteria. Twelve patients received active stimulation, and thirteen patients received placebo stimulation. The primary outcome measure was the change in two parallel versions of the California Verbal Learning Test-Second Edition, a standardized neuropsychological memory test normalized by age and gender. The secondary outcome measures were the Mini Mental State Examination, clock-drawing test, and Trail Making Test A and B.
  
  
  RESULTS
  Changes in the California Verbal Learning Test-Second Edition scores were not significantly different between the active and placebo stimulation groups for immediate recall (p = 0.270), delayed recall (p = 0.052), or recognition (p = 0.089). There were nonsignificant differences in score changes on the Mini Mental State Examination (p = 0.799), clock-drawing test (p = 0.378), and Trail Making Test A (p = 0.288) and B (p = 0.093). Adverse effects were not observed.
  
  
  CONCLUSIONS
  Compared with placebo stimulation, active tDCS stimulation in this clinical trial did not significantly improve verbal memory function in Alzheimer's disease. This study differs from previous studies in terms of the stimulation protocol, trial design, and application of standardized neuropsychological memory assessment.
  
  
  BACKGROUND
  ClinicalTrials.gov identifier NCT02518412 . Registered on 10 August 2015.
authors.affiliation: Department of Psychology, Research Group for Cognitive Neuroscience, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway. martin.k.bystad@uit.no.|Department of Geropsychiatry, University Hospital of North Norway, Tromsø, Norway. martin.k.bystad@uit.no.
authors.forename: Martin
authors.initials: M
authors.lastname: Bystad
authors.affiliation: Department of Geropsychiatry, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Ole
authors.initials: O
authors.lastname: Grønli
authors.affiliation: Department of Psychology, Research Group for Cognitive Neuroscience, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.|Department of Geropsychiatry, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Ingrid Daae
authors.initials: ID
authors.lastname: Rasmussen
authors.affiliation: Department of Psychology, Research Group for Cognitive Neuroscience, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.
authors.forename: Nina
authors.initials: N
authors.lastname: Gundersen
authors.affiliation: Department of Psychology, Research Group for Cognitive Neuroscience, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.
authors.forename: Lene
authors.initials: L
authors.lastname: Nordvang
authors.affiliation: Department of Psychology, Research Group for Cognitive Neuroscience, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.
authors.forename: Henrik
authors.initials: H
authors.lastname: Wang-Iversen
authors.affiliation: Department of Psychology, Research Group for Cognitive Neuroscience, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.|Department of Child and Adolescent Psychiatry, University Hospital of North Norway, Tromsø, Norway.
authors.forename: Per M
authors.initials: PM
authors.lastname: Aslaksen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology / Q000523:psychology* / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D008570:Memory, Short-Term; D008609:Mental Status Schedule; D009483:Neuropsychological Tests; D021641:Recognition, Psychology; D013702:Temporal Lobe / Q000503:physiopathology*; D065908:Transcranial Direct Current Stimulation
keywords: Alzheimer’s disease; Memory; Neuromodulation; Neuropsychology; Randomized controlled trial; Transcranial direct current stimulation