Concurrent and Predictive Validity of Arm Kinematics With and Without a Trunk Restraint During a Reaching Task in Individuals With Stroke.

Abstract

To examine the concurrent and predictive validity of measurements of kinematic variables during reaching tasks with and without a trunk constraint in individuals with stroke. Randomized controlled trials. Hospitals and a laboratory. Individuals with stroke (N=95) enrolled in previous and ongoing clinical trials. Upper limb training protocols were 90 to 120 minutes of intervention every weekday for 3 to 4 weeks. Functional capacity was assessed using the Action Research Arm Test and motor impairment using the Fugl-Meyer Assessment for the Upper Extremity. Movement kinematics were measured during a reaching task with and without a trunk constraint. We derived 5 endpoint control variables and 3 joint recruitment variables for estimating concurrent and predictive validity. The adjusted R(2) values for the constraint tasks ranged from .24 to .38 and for the unconstraint tasks from .29 to .40. Movement time was the most prominent kinematic variable for the Fugl-Meyer Assessment for the Upper Extremity before and after the intervention (P<.05). For the Action Research Arm Test, movement time and endpoint displacement were the most significant variables before and after the intervention, respectively (P<.05). Measuring kinematic performance during an unconstrained task is appropriate and possibly sufficient to represent motor impairment and functional capacity of individuals with stroke. Movement time is the dominant variable associated with motor impairment and functional capacity, and endpoint displacement is unique in reflecting functional capacity of individuals with stroke.