- Dual-tDCS enhanced motor skill learning and retention in chronic hemiparetic stroke patients (95 /125)
- Dual-tDCS combined to training induced an increase in FC in the ipsilesional M1, PMd (and SMA) that lasted up to 1 week (120 /125)
- Both seed and ICA-based analyses showed a FC reorganisation following dual-tDCS (between ipsilesional M1 and PMd) (114/125)
- This study demonstrated changes of FC lasting well beyond what has been previously reported after a single session of tDCS (125 / 125)
- tDCS, combined with motor learning, has lasting effect upon FC and could be an efficient tool in neurorehabilitation (121 /125)
Recent studies using resting-state functional magnetic resonance imaging (rs-fMRI) demonstrated that changes in functional connectivity (FC) after stroke correlate with recovery.
The aim of this study was to explore whether combining motor learning to dual transcranial direct current stimulation (dual-tDCS, applied over both primary motor cortices (M1)) modulated FC in stroke patients. Twenty-two chronic hemiparetic stroke patients participated in a baseline rs-fMRI session. One week later, dual-tDCS/sham was applied during motor skill learning (intervention session); one week later, the retention session started with the acquisition of a run of rs-fMRI imaging.
The intervention + retention sessions were performed once with dual-tDCS and once with sham in a randomised, cross-over, placebo-controlled, double-blind design. A whole-brain independent component analysis based ANOVA demonstrated no changes between baseline and sham sessions in the somatomotor network, whereas a FC increase was observed one week after dual-tDCS compared to baseline (qFDR < 0.05, t(63) = 4.15). A seed-based analysis confirmed specific stimulation-driven changes within a network of motor and premotor regions in both hemispheres. At baseline and one week after sham, the strongest FC was observed between the M1 and dorsal premotor cortex (PMd) of the undamaged hemisphere. In contrast, one week after dual-tDCS, the strongest FC was found between the M1 and PMd of the damaged hemisphere. Thus, a single session of dual-tDCS combined with motor skill learning increases FC in the somatomotor network of chronic stroke patients for one week.