Using Transcranial Direct Current Stimulation to Treat Symptoms in Mild Cognitive Impairment and Alzheimer’s Disease

Abstract

Transcranial direct current stimulation (tDCS) has recently been investigated as a potential nonpharmacological treatment for individuals with mild cognitive impairment (MCI) and Alzheimer's disease (AD). A comprehensive literature search was performed on tDCS studies published until March 2017 using MEDLINE, Embase and PsychINFO databases. 12 articles with a total of 202 MCI or AD participants were included. Although ten of the 12 studies demonstrated positive findings with tDCS, two studies reported no effect on cognition. There was a wide range of methodological approaches used and in the cognitive functions measured. The variability in treatment response may be related to the heterogeneity in stimulation parameters including the site of stimulation, and cognitive assessments used. Patient-related factors including individual psychological, biological, and physiological status at the time of stimulation may also influence treatment response. We recommend that more comparative studies using similar patient factors and study parameters are needed in order to better understand the efficacy of tDCS in MCI and AD.

Effects of bilateral transcranial direct current stimulation on working memory and global cognition in older patients with remitted major depression: A pilot randomized clinical trial

“…35 In one review article, 10 out of 12 studies in patients with AD or MCI showed improved cognition with tDCS. 40 Studies in patients with cognitive disorders have shown the benefits of tDCS combined with cognitive tasks on visual memory, attention and executive function. 41,42 The positive effects of this combination could be due to tDCS acutely improving attention or executive function during the cognitive task leading to improved learning.…”

Anodal Transcranial Direct Current Stimulation Can Improve Spatial Learning and Memory and Attenuate Aβ42 Burden at the Early Stage of Alzheimer’s Disease in APP/PS1 Transgenic Mice

“…Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation technique that delivers a constant low-intensity subthreshold direct current to specific regions of the brain through electrodes placed on the scalp, thereby regulating cell transmembrane potential depolarization and hyperpolarization (Bindman et al, 1962;Nitsche and Paulus, 2000) and altering neuronal activity and excitability of the cerebral cortex (Nitsche et al, 2008;Stagg et al, 2018). A number of clinical and basic studies have found that tDCS treatment can improve memory and cognitive dysfunction in patients and animal with AD (Yu et al, 2014;Hsu et al, 2015;Liu et al, 2017;Cruz Gonzalez et al, 2018). However, few studies have validated tDCS in the preclinical AD phase, and little is known about the mechanism of action.…”

Impact of 3-Day Combined Anodal Transcranial Direct Current Stimulation-Visuospatial Training on Object-Location Memory in Healthy Older Adults and Patients with Mild Cognitive Impairment

“…Including several covariates to for inter-individual differences in tDCS response [108][109][110] strengthened the observed beneficial effect of training success in MCI (Model 1). Specifically, lower age, female gender, a lower BDI baseline score, and higher MWT score were associated with increased training success.…”