# Comparative effects of transcranial direct and alternating current stimulation combined with cognitive-motor dual-task training on functional and cognitive recovery in stroke survivors

## TL;DR

This study compares how combining brain stimulation with dual-task training helps stroke survivors recover physically and cognitively.

## Contribution

The study provides evidence that tDCS combined with CMDT leads to greater functional and cognitive improvements in stroke survivors compared to tACS or sham.

## Key findings

- tDCS combined with CMDT improved physical function (FMA-LE) more than tACS or sham.
- tDCS enhanced cognitive performance (VCAT) compared to sham.
- Both tDCS and tACS improved dual-task performance and mood more than sham.

## Abstract

This study aimed to determine whether dual-target anodal transcranial direct current stimulation (tDCS) or transcranial alternating current stimulation (tACS) applied over the primary motor cortex (M1) and left dorsolateral prefrontal cortex (DLPFC), when combined with cognitive-motor dual-task training (CMDT), could enhance cognitive, physical, and mood outcomes in stroke survivors.

A single-blind, three-arm randomized controlled trial was conducted involving 72 stroke survivors. Participants were randomized to receive 15 sessions of dual-site (M1 + DLPFC) anodal tDCS, tACS, or sham stimulation, all administered concurrently with CMDT. Primary outcomes included cognitive performance (Visual Cognitive Assessment Test, VCAT) and physical function (Fugl-Meyer Lower Limb, FMA-LE). Secondary outcomes comprised the Trail-Making Test (TMT-A/B), Berg Balance Scale (BBS), Timed Up and Go (TUG) under single and dual-task conditions, and the Hamilton Depression Scale (HAMD). Data were analyzed using ANOVA with Bonferroni-adjusted pairwise comparisons.

Significant group × time interactions were observed across multiple functional domains. The tDCS + CMDT group showed superior improvements in FMA-LE scores vs. both tACS + CMDT and sham + CMDT (post-hoc p < 0.05 each), but in BBS scores only vs. sham + CMDT (p < 0.05). Additionally, tDCS significantly enhanced VCAT performance compared to sham (p < 0.05). Both tDCS and tACS groups produced comparable and significantly greater improvements than sham in TUG-Dual performance and HAMD reduction (p < 0.001).

Dual-site anodal tDCS and tACS combined with CMDT represent safe and effective neuromodulatory strategies for stroke rehabilitation. While tDCS confers greater benefits in promoting local motor plasticity and global cognitive gains, tACS achieves functionally equivalent improvements in network-dependent tasks such as dual-task performance and mood regulation.

These findings provide novel, evidence-based guidance for tailoring non-invasive brain stimulation (NIBS) modalities to specific neurorehabilitation goals, highlighting that combining tDCS or tACS with CMDT can enhance neuroplasticity and translate into meaningful functional recovery in stroke survivors.

Clinical Trial Registry (ChiCTR2400092849).