Dose Response to Upper Extremity Stroke Rehabilitation Varies by Individual: Early Indicators of Treatment Response

BACKGROUND: Dose response has remained a priority area in motor rehabilitation research for decades, prompting several large randomized trials and meta-analyses. These between-subjects comparisons have revealed equivocal relationships between the duration of motor practice and rehabilitation response. Prior reliance on time-consuming clinical assessments made it infeasible to capture within-subjects dose response, as tracking the dose-response trajectory of an individual requires dozens of repeated administrations. METHODS: This secondary observational cohort analysis of existing data from the gaming arms of the VIGoROUS multisite trial (Video Game Rehabilitation for Outpatient Stroke) describes the rehabilitation dose response of 80 participants with mild-moderate chronic stroke. The 3-dimensional joint position data were captured via the Kinect v2 optical sensor as participants completed a prescribed 15 hours of in-home unsupervised game-based motor practice. Kinematic dose response trajectories were fitted from hundreds to thousands of in-game repetitions for 4 separate upper extremity movements for each participant. RESULTS: Of 75 participants with sufficient data for dose-response analysis, 85% showed improved motor capacity for at least 1 movement. Dose response was bimodal; 42% required <5 hours of motor practice before reaching a plateau in movement kinematics, whereas 55% required >10 and 34% required >30 hours. We could predict with 93% accuracy whether or not an individual would ultimately respond to game-based motor practice within 5 hours of gameplay. CONCLUSIONS: Dose response varies considerably between individuals. About half of chronic stroke patients benefit from higher doses of motor practice than the current standard of care. Individualized dose-response data from motion capture rehabilitation gaming can guide clinical decision-making early on in treatment. REGISTRATION:URL: https://www.clinicaltrials.gov; Unique identifier: NCT02631850.