Transcranial Direct Current Stimulation of Dorsolateral Prefrontal Cortex of Major Depression: Improving Visual Working Memory, Reducing Depressive Symptoms

Abstract

Recent studies on major depression have used non-invasive brain stimulation techniques such as transcranial direct current stimulation to improve impaired emotion and cognition in MD. However, such experiments have yielded mixed results specifically with respect to cognition in MD. This study aimed to investigate whether anodal and cathodal tDCS applied over dorsolateral prefrontal cortex (DLPFC), would significantly improve visual working memory and reduce depressive symptoms in patients with MD. Thirty (N=30) patients with major depression were randomly assigned to receive either experimental (active) or control (sham) tDCS. Participants underwent a series of visual memory neuropsychological tasks and Beck Depression Inventory (BDI) and Hamilton Depression Scale (HDRS). After 10 sessions of anodal and cathodal tDCS, patients showed improved performance in visual working memory tasks. Specifically, active stimulation improved visual memory performance for the experimental group relative to baseline, whereas sham stimulation did not differentiate performance from baseline in the control group.