Motor strategies and bilateral transfer in sensorimotor learning of patients with subacute stroke and healthy subjects. A randomized controlled trial

Bilateral transfer, i.e. the capacity to transfer from one to the other hand a learned motor skill, may help the recovery of upper limb functions after stroke.To investigate the motor strategies at the basis of sensorimotor learning involved in bilateral transfer.Randomized controlled trial.Neurorehabilitation Hospital.Eighty right-handed participants (65 ± 13 years old): 40 patients with subacute stroke, 40 control healthy subjects.Subjects performed the 9 hole-peg-test twice in an order defined by random allocation: first with low and then with high skilled hand (LS-HS) or the reverse (HS-LS). Time spent to complete the test and filling sequence were recorded, together with maximum pinch force (assessed using a dynamometer), upper limb functioning (Motricity Index), spasticity (modified Ashworth Scale), limb dominance (Edinburgh Handeness Inventory).As expected, in patients, the performance was found related to the residual pinch force (P0.001), upper limb motricity (P=0.006) and side of hemiparesis (P=0.016). The performances of all subjects improved more in HS-LS than in LS-HS subgroups (P=0.043). The strategy adopted in the first trial influenced the velocity in the second one (P=0.030).Bilateral transfer was observed from high to low skilled hand. Learning was not due to a mere sequence repetition, but on a strategy chosen on the basis of the previous performance.The affected hand of patients with subacute stroke may benefit from sensorimotor learning occurred with the un-affected hand.