Effects of multisession frontoparietal network anodal tDCS and cognitive rehabilitation on subjective cognitive impairment: a double-blind RCT

Repeated sessions of cognitive training and anodal transcranial direct current stimulation (tDCS) have the potential to enhance cognition in patients with subjective cognitive impairment (SCI). We hypothesized that this combination would improve memory function and reduce subjective complaints in SCI patients. In a randomized sham-controlled double-blind study, 35 SCI patients (ages 35–50) were assigned to one of two intervention groups in a 1:1 ratio using a computer-generated random number sequence. The intervention consisted of 10 sessions of cognitive training over three weeks, with concurrent 2-mA anodal tDCS over the left dorsolateral prefrontal cortex and left posterior parietal cortex. 30 participants completed the intervention and were included in the final analysis. The primary outcome variables were the scores on computerized tests of the Cambridge Neuropsychological Test Automated Battery (CANTAB). Secondary outcomes included scores on tests evaluating general cognition using the Montreal Cognitive Assessment (MOCA), sleep quality, anxiety, depression, and degree of subjective complaints. Changes in scores during the study period were compared between groups. The study was completed by 35 participants with SCI. The real tDCS group showed significantly better CANTAB scores compared to the sham group (p < 0.05). General cognition (MOCA) scores did not differ between groups, but mood and sleep quality improved significantly in the real tDCS group. In conclusion, our trial suggests that cognitive training combined with anodal tDCS was associated with significantly enhanced performance and reduced subjective complaints in SCI patients. Future research should explore individualized protocols for optimizing treatment. Trial registration The clinical trial registration code was obtained from the Iranian Registry of Clinical Trials (IRCT20181109041598N2).