Article

Motor training alone or combined with transcranial direct current
stimulation (tDCS) positioned over the motor cortex (M1) improves motor function
in chronic stroke. Currently, understanding of how tDCS influences the process of
motor skill learning after stroke is lacking. OBJECTIVE: To assess the effects of
tDCS on the stages of motor skill learning and on generalization to untrained
motor function. METHODS: In this randomized, sham-controlled, blinded study of 56
mildly impaired chronic stroke patients, tDCS (anode over the ipsilesional M1 and
cathode on the contralesional forehead) was applied during 5 days of training on
an unfamiliar, challenging fine motor skill task (sequential visual isometric
pinch force task). We assessed online and offline learning during the training
period and retention over the following 4 months. We additionally assessed the
generalization to untrained tasks. RESULTS: With training alone (sham tDCS
group), patients acquired a novel motor skill. This skill improved online,
remained stable during the offline periods and was largely retained at follow-up.
When tDCS was added to training (real tDCS group), motor skill significantly
increased relative to sham, mostly in the online stage. Long-term retention was
not affected by tDCS. Training effects generalized to untrained tasks, but those
performance gains were not enhanced further by tDCS. CONCLUSIONS: Training of an
unfamiliar skill task represents a strategy to improve fine motor function in
chronic stroke. tDCS augments motor skill learning, but its additive effect is
restricted to the trained skill.

Langue : ANGLAIS