Kinematic Variables Quantifying Upper-Extremity Performance After Stroke During Reaching and Drinking From a Glass

BACKGROUND: Three-dimensional kinematic analysis provides quantitative and qualitative assessment of upper-limb motion and is used as an outcome measure to evaluate impaired movement after stroke. The number of kinematic variables used, however, is diverse, and models for upper-extremity motion analysis vary. OBJECTIVE: The authors aim to identify a set of clinically useful and sensitive kinematic variables to quantify upper-extremity motor control during a purposeful daily activity, that is, drinking from a glass. METHODS: For this purpose, 19 participants with chronic stroke and 19 healthy controls reached for a glass of water, took a sip, and placed it back on a table in a standardized way. An optoelectronic system captured 3-dimensional kinematics. Kinematical parameters describing movement time, velocity, strategy and smoothness, interjoint coordination, and compensatory movements were analyzed between groups. RESULTS: The majority of kinematic variables showed significant differences between study groups. The number of movement units, total movement time, and peak angular velocity of elbow discriminated best between healthy participants and those with stroke as well as between those with moderate (Fugl-Meyer scores of 39-57) versus mild (Fugl-Meyer scores of 58-64) arm impairment. In addition, the measures of compensatory trunk and arm movements discriminated between those with moderate and mild stroke impairment. CONCLUSION: Kinematic analysis in this study identified a set of movement variables during a functional task that may serve as an objective assessment of upper-extremity motor performance in persons who can complete a task, such as reaching and drinking, after stroke.