Abstract
BACKGROUND: Conventional clinical tools for assessing upper limb motor function often lack the sensitivity and specificity needed to detect subtle changes in motor performance and may be subject to bias. Kinematic assessment offers a potential solution by providing objective, precise, and detailed data on movement quality. However, it is typically associated with high costs, complex equipment, time-consuming procedures, and the need for controlled environments, all of which limit its accessibility and practicality in clinical settings. This study aimed to evaluate the reliability, validity, and sensitivity of a low-cost, touchscreen-based kinematic assessment tool for measuring upper limb function in individuals post-stroke. METHODS: Sixty-four individuals with stroke participated in this study. Participants performed a visually guided reaching task on a large touch screen that consisted in reaching from a central target to five outer targets arranged in a circular pattern, each at a time, and then returning to the central target. Their motor function was assessed using the Fugl-Meyer Assessment for Upper Extremity, the Box and Block Test, and the Nine Hole Peg Test. Kinematic measures of the trajectories performed during the reaching task were extracted and analyzed for reliability, convergent validity with clinical assessments, and sensitivity to impairment severity. RESULTS: The kinematic measures demonstrated good to excellent test-retest reliability, with intraclass correlation coefficients ranging from moderate to excellent. The convergent validity analysis revealed multiple significant correlations between the kinematic parameters and clinical assessments, particularly in tests requiring higher skill and precision, such as the Coordination and Speed subscale of the Fugl-Meyer Assessment for Upper Extremity and the Nine Hole Peg Test. Additionally, the touchscreen-based assessment was sensitive to the severity of motor impairment, as reflected by notable differences in the kinematic measures among participants with varying levels of upper limb function. CONCLUSIONS: The touchscreen-based kinematic assessment offered an affordable yet reliable, valid, and sensitive alternative for evaluating upper limb kinematics in individuals with stroke, which could complement clinical assessments by offering additional insights into motor performance. Furthermore, its low cost, high speed, and ease of use make it a practical option for widespread clinical adoption.