Effects of transcranial direct current stimulation on working memory in healthy older adults: a systematic review
This mini systematic review aimed to investigate the effects of transcranial direct current stimulation (tDCS) on working memory in older adults without cognitive impairment. The search was carried out in three different databases for all human trials published from 2005 to 2015, assessing the effects of tDCS on working memory in healthy older adults. The screening was conducted by two independent reviewers. Four studies were included. All studies combined anodal tDCS (applied to pre-frontal or parietal cortex) with working memory training. Anodal tDCS seems to be able to modulate working memory performance. Nonetheless, there is evidence that suggests that variables, such as level of education, working memory task and time of assessment can moderate the effect. Recommendations for futures studies are also provided.