A novel tool for characterising upper limb function in progressive multiple sclerosis through kinematic assessment

Introduction Current upper limb assessment methods in MS rely on measuring duration in tasks like the nine-hole peg test (9HPT). Kinematic techniques may provide a more useful measure of functional change in clinical and research practice. The aim of this study was to assess upper limb function prospectively in people with progressive MS using a kinematic 3D motion capture system and compare with current measures. Methods 42 people with progressive MS (PwPMS) and 15 healthy controls reached-and-grasped different objects whilst recorded by a kinematic assessment system. 9HPT, Expanded Disability Status Scale (EDSS), and patient reported outcome measures (PROs) were collected. All measures were taken at baseline for PwPMS and controls, and again at six months for PwPMS. Results Relative to controls, PwPMS had significantly longer reaction (0.11 s, p < 0.05) and reach (0.25 s, p < 0.05) times. PwPMS took longer to pick-up (0.34 s, p < 0.05), move (0.14 s, p < 0.05), and place (0.18 s, p < 0.05) objects. PwPMS had lower peak velocities when reaching (7.4 cm/s, p < 0.05) and moving (7.3 cm/s, p < 0.05) objects. Kinematic assessment demonstrated consistent differences between PwPMS with mild and severe upper limb dysfunction as defined by PROs, which were not captured by 9HPT or EDSS in this group. PwPMS demonstrated altered grip apertures profiles, as measured by their ability to complete individual parts of the reach and grasp task, between the baseline and follow-up timepoints. Conclusions We have created and tested a novel upper limb function assessment tool which has detected changes and characteristics in hand function, not currently captured by the EDSS and 9HPT.