Transcranial Direct Current Stimulation: Cognitive Effects in Elderly With Depression

In elderly patients with remitted major depressive disorder (MDD), a 10-day course of standalone bilateral dorsolateral prefrontal cortex (DLPFC) anodal transcranial direct current stimulation (tDCS) was well tolerated but failed to improve global cognition or working memory at 14 days’ or at 90 days’ postintervention. Results of the analysis were published in the International Journal of Geriatric Psychiatry.

The investigators sought to evaluate the impact of 10 days of bilateral anodal tDCS of the DLPFC on working memory and global cognition in elderly patients with remitted MDD at 14 days—the primary study outcome—and at 90 days—the secondary outcome—following use of the intervention.

A pilot randomized, controlled, double-blind study (ClinicalTrials.gov identifier: NCT02212366) in elderly patients with remitted MDD was conducted at the Centre for Addiction and Mental Health in Toronto, Ontario, Canada. The participants, were ≥60 years of age, and had experienced a prior single or recurrent episode of MDD, but were currently in full remission. All of the participants received a 10-day course of either active or sham bilateral DLPFC anodal tDCS. A total of 33 individuals were enrolled in the study, of whom 18 were randomized to the active tDCS group and 15 to the sham tDCS group. All participants other than 1 individual from the sham treatment arm completed the tDCS course.

At both 14 days’ and 90 days’ postintervention, no differences were reported between the groups with respect to global cognition or working memory performance. Over time, participants in both of the treatment arms demonstrated promising changes in global cognition and working memory.

Limitations of the study include small sample size, the lack of a no treatment group, and differential effects of mood may have influenced participants’ cognitive performance.

The investigators concluded that although tDCS was well tolerated in older patients with remitted MDD, those who received the active treatment fared no better with respect to improvements in global cognition and working memory than did those who received the sham therapy. Additional studies are warranted, in order to explore the use of tDCS with alternative parameters or in combination with other interventions designed to enhance cognition, such as cognitive exercises, in this elderly population.

Reference                                                                                                                                                    

Kumar S, Batist J, Ghazala Z, et al. 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 [published online June 11, 2020]. Int J Geriatr Psychiatry. doi: 10.1002/gps.5361.