Arm training in Multiple Sclerosis using Phantom: Clinical relevance of robotic outcome measures

Upper limb weakness due to Multiple Sclerosis has a major negative effect on the functional activities of the patient. Promising developments in the field of rehabilitation robotics may enable additional exercise. This study aims to investigate which types of robotic outcome measures are clinically relevant, in preparation of the evaluation for intervention studies.Within this context, appropriate movement tasks and tests for the haptic PHANTOM end-effector robot were designed in a virtual environment. These tasks focused on spatial accuracy, object manipulation and speed. Outcome measures were: 1) virtual movement tests, recorded by the robot to quantify motor control; 2) clinical outcome measures such as the Motricity Index, Jamar and MicroFET hand-held dynamometer to evaluate muscle strength; and the Nine Hole Peg Test, Purdue Pegboard, ARAt and TEMPA to asses upper limb function and manual dexterity.10 healthy controls performed the virtual movement tasks using the Phantom as interface. 21 MS subjects with upper limb dysfunction caused by muscle weakness were included in an interventional training study. Pearson correlations were calculated at baseline between the performance on the three virtual movement tasks and the clinical tests on impairment and activity level. The virtual movement tests discriminated between healthy controls and MS patients with hand dysfunction. In the MS patient group, no significant correlations were found between muscle strength tests and virtual movement tasks, while mainly significant correlations were found between specific functional measures (specifically ARAt and Purdue pegboard test) and virtual movement tasks.