The effects of multi-session dual-tDCS on the bilateral transfer of motor skill learning in patients with stroke

Abstract

Objective: This study investigates the potential effects of combining motor skill learning transfer from the unaffected to the affected hand with multiple sessions of dual-transcranial direct current stimulation (tDCS) over the primary motor cortex to enhance motor skills in stroke patients. Methods: Eleven stroke patients participated in a randomized, sham-controlled, double-blind crossover study. Over two periods separated by a 3-week washout, participants underwent either sham or dual-tDCS concurrently with serial response time tasks (SRTT). Each intervention included 20 min of stimulation during SRTT for three consecutive days. The skill index, the primary variable, was assessed pre-intervention, immediately postintervention, and 24 h later. Results: Both groups showed significant improvement in motor skill learning across the three intervention days (P < 0.001). The dual-tDCS group demonstrated significantly greater skill improvement in the affected hand compared to the sham group (P < 0.01), while no significant differences were found for the unaffected hand (P = 0.98). Conclusions: Multi-session dual-tDCS combined with motor learning tasks significantly enhances motor skill transfer to the affected hand in stroke patients, with greater and more durable effects compared to sham stimulation. Significance: This approach may improve bilateral motor skill transfer and hand fatigue management in stroke rehabilitation.