Movement Kinematics During a Drinking Task Are Associated With the Activity Capacity Level After Stroke

Background. Kinematic analysis is a powerful method for an objective assessment of movements and is increasingly used as an outcome measure after stroke. Little is known about how the actual movement performance measured with kinematics is related to the common traditional assessment scales. The aim of this study was to determine the relationships between movement kinematics from a drinking task and the impairment or activity limitation level after stroke. Methods. Kinematic analysis of movement performance in a drinking task was used to measure movement time, smoothness, and angular velocity of elbow and trunk displacement (TD) in 30 individuals with stroke. Sensorimotor impairment was assessed with the Fugl-Meyer Assessment (FMA), activity capacity limitation with the Action Research Arm Test (ARAT), and self-perceived activity difficulties with the ABILHAND questionnaire. Results. Backward multiple regression revealed that the movement smoothness (similarly to movement time) and TD together explain 67% of the total variance in ARAT. Both variables uniquely contributed 37% and 11%, respectively. The TD alone explained 20% of the variance in the FMA, and movement smoothness explained 6% of the variance in the ABILHAND. Conclusions. The kinematic movement performance measures obtained during a drinking task are more strongly associated with activity capacity than with impairment. The movement smoothness and time, possibly together with compensatory movement of the trunk, are valid measures of activity capacity and can be considered as key variables in the evaluation of upper-extremity function after stroke. This increased knowledge is of great value for better interpretation and application of kinematic data in clinical studies.