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

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.

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 post-intervention, and 24 h later.

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).

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.

This approach may improve bilateral motor skill transfer and hand fatigue management in stroke rehabilitation.