Characterizing practice-dependent motor learning after a stroke

Abstract

Background: After stroke, patients must learn to use residual motor function correctly. Consistently, motor learning is crucial in stroke motor recovery. We assessed motor performance, practice-dependent on-line motor learning, and factors potentially affecting them in stroke patients.

Methods: This is a cross-sectional observational study. Twenty-six patients with first brain stroke leading to upper limb motor deficit in the subacute or chronic timeframe were enrolled. They performed a Finger Tapping Task (FTT) with both the affected and unaffected limbs. We assessed how patients learn to perform motor tasks despite the motor deficit and the differences in performance between the unaffected and affected limbs. Furthermore, by randomizing the order, we evaluated the possible inter-limb transfer of motor learning (i.e. transfer of a motor skill learned in one limb to the opposite one). Moreover, sleep, attention, anxiety, and depression were assessed through specific tests and questionnaires.

Results: Improved FTT accuracy and completed sequences for the affected limb were observed, even if lower than for the unaffected one. Furthermore, when patients initially performed the FTT with the unaffected limb, they showed higher accuracy in subsequent task completion with the affected limb than subjects who started with the affected limb. Only anxiety and attentional abilities showed significant correlations with motor performance.

Conclusions: This work provides relevant insights into motor learning in stroke. Practice-dependent on-line motor learning is preserved in stroke survivors, and an inter-limb transfer effect can be observed. Attentional abilities and anxiety can affect learning after stroke, even if the effect of other factors cannot be excluded.

Keywords: Finger tapping Task (FTT); Inter-limb transfer; Motor learning; Rehabilitation; Stroke.

Fig. 1

Graphical representation of the finger tapping task. Created with BioRender.com

Fig. 2

Graphical representation of the average trend of the parameters ACC (a), Seq (b), and ACC/Seq (c) at the FTT of the unaffected (dark grey) and affected limb (light grey) in the 6 trials performed. Error bars represents the standard deviation. Abbreviations: ACC = accuracy, ACC/Seq = accuracy/sequences, FTT = finger tapping task, Seq = sequences

Fig. 3

Boxplots of the difference in accuracy at the first block of the FTT between the patients who started the test with the affected (light grey) and unaffected limb (dark grey). Whiskers represent the minimum and maximum values of the sample. The x represents the mean. Abbreviations: FTT = Finger tapping task

Fig. 4

Graphical representation of the hypothesised model of inter-limb transfer in stroke patients. The first column depicts the effect of randomization (i.e., performing the task first with the affected or unaffected limb) and concordance (i.e., whether the dominant hand matches the paretic one) on the performance of the affected upper limb (second column displaying ACC_online). A and B show conditions where the task is performed first with the affected upper limb, resulting in low or moderately low performance depending on whether the paretic hand does not match (A) or matches (B) the dominant one, respectively. Conversely, C and D show conditions where the task is performed first with the unaffected limb, assessing the effects of this motor priming on subsequent performance of the affected limb. Considering the hypothesized inter-limb transfer of learning, the performance of the affected upper limb is moderately high if the unaffected limb does not match the dominant one (C) and high if it matches the dominant one (D). C and D suggest that better performance with the first limb (the unaffected and dominant limb) corresponds to greater motor pattern consolidation and performance of the affected limb. Created with BioRender.com