Speed-Biased Training Temporarily Improves Motor Performance of the Paretic Arm Compared to Accuracy-Biased Training...

BackgroundDespite the prevalence of upper extremity (UE) limitations after stroke, few training interventions prioritize fast movement speeds during rehabilitation.ObjectivesTo compare the effects of an equivalent dose (in the number of trials) of speed versus accuracy training in chronic stroke with mild-to-moderate impairments who have no direct cerebellar damage.Patients and MethodsIn this Phase-1 randomized controlled trial, we randomized 42 participants to either a speed or an accuracy arm-movement training condition. Participants moved their paretic hands through complex tracks, with 2080 trials in 4 sessions within a week. Speed and accuracy were manipulated by displaying 5 cm-wide or 1.25 cm-wide tracks or providing feedback based on average speed and accuracy in the Speed and Accuracy groups, respectively. We measured changes in kinematics in a 3-target test, in the speed-accuracy trade-off in a modified Fitts' test of the paretic arm during goal-directed reaching, and clinical outcomes (ie, UE Fugl-Meyer, Action Research Arm Test, and Box and Block Test) at 3 days and 1-month post-training.ResultsSpeed training led to significantly faster and smoother movements with more symmetric reach velocity profiles at the 3-day post-test, consistent with better feedforward control. Speed training temporarily improved the speed-accuracy tradeoff. At 1 month, however, most gains in the 3-target test and in the modified Fitts' test were lost.ConclusionSpeed training led to greater gains in kinematics of goal-directed actions than accuracy training, notably in a 3-day post-test. Our results suggest that training programs with high repetitions of fast movements may improve paretic arm reaching performance. The trial is registered at ClinicalTrials.gov under ID NCT05013762.