Dual-tDCS Enhances Online Motor Skill Learning and Long-Term Retention in Chronic Stroke Patients

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Motor Control

Background:

• Motor learning is vital for stroke recovery and neurorehabilitation.
• Transcranial direct current stimulation (tDCS) is a potential method to enhance motor learning.
• Dual-tDCS applied bilaterally over primary motor cortices (M1) was investigated for improving paretic hand motor skill learning and retention.

Purpose of the Study:

• To test if dual-tDCS over M1 enhances online motor skill learning with the paretic hand.
• To determine if dual-tDCS improves long-term retention of motor skills.
• To assess the generalization of learned skills after dual-tDCS.

Main Methods:

• Eighteen chronic stroke patients underwent a randomized, cross-over, placebo-controlled, double-blind trial.
• Participants learned a complex visuomotor skill using the paretic hand during dual-tDCS or sham dual-tDCS sessions.
• Motor skill performance was assessed at baseline, immediately post-intervention, and one week later.

Main Results:

• Dual-tDCS significantly enhanced the amount and speed of online motor skill learning compared to sham (p < 0.001).
• The benefits of dual-tDCS on learning were maintained for at least one hour post-intervention.
• One week later, dual-tDCS resulted in superior long-term retention (+44%) compared to sham (+4%), with improvements generalizing to untrained tasks.

Conclusions:

• A single dual-tDCS session during paretic hand training significantly improved motor skill learning, retention, and generalization in stroke patients.
• Dual-tDCS offers a promising approach for enhancing post-stroke neurorehabilitation.
• The combination of motor skill training with dual-tDCS is effective for improving functional recovery after stroke.