Role of tDCS plus virtual reality in enhancing cognitive function in patients with chronic stroke: a quasi-randomized clinical trial

Background: Alone or combined with other advanced rehabilitative treatments, non-invasive transcranial direct current stimulation (tDCS) is a promising tool to augment neuroplasticity as well as improve cognitive function post stroke. Objective: To investigate the psychological and neurophysiological effects of tDCS application combined with cognitive virtual reality training (VRT) in patients with chronic ischemic stroke. Material and methods: Twenty subjects were enrolled in this quasi-randomized pilot study and assigned to the experimental (EG) or control groups (CG). The EG received VRT combined with tDCS, while the CG received the VRT with sham-tDCS, five times a week for 4 weeks. Each patient was evaluated using a psychometric battery, including Mini Mental State Examination (MMSE), Hamilton Rating Scale (HRS-D), and Frontal Assessment Battery (FAB), at the beginning (T0) and the end (T1) of the study. Additionally, a neurophysiology technician measured the brain electrical activity through event-related potential P300. Results: A significant improvement in MMSE scores from T0 to T1 was observed in the EG. A significant improvement in FAB scores was observed over time (i.e. at the intragroup analysis), with greater gains in the group receiving active tDCS. On the contrary, both groups showed a significant reduction in depressive symptoms scores over time. A key finding of the study was the enhancement of cognitive processing speed, as indicated by reduced P300 latency, in the EG. Conclusions: This study suggests that tDCS may potentiate the effects of VR by promoting neuroplasticity and improving the efficiency of cognitive networks, ultimately contributing to better recovery outcomes in patients with stroke.