Assessment of upper limb motor function in patients with multiple sclerosis using the Virtual Peg Insertion Test: A pilot study

Quantifying and tracking upper limb impairment is of key importance to the understanding of disease progress, establishing patient-tailored therapy protocols and for optimal care provision. This paper presents the results of a pilot study on the assessment of upper limb motor function in patients with multiple sclerosis (MS) with the Virtual Peg Insertion Test (VPIT). The test consists in a goal-directed reaching task using a commercial haptic display combined with an instrumented handle and virtual environment, and allows for the extraction of objective kinematic and dynamic parameters. Ten MS patients and eight age-matched healthy subjects performed five repetitions of the VPIT with their dominant and non-dominant hand. Upper limb movements were found to be significantly slower, less smooth and less straight compared to healthy controls, and the time to complete the VPIT was well correlated with the conventional Nine Hole Peg Test (r=0.658, p<;0.01). Tremor in the range of 3-5 Hz could be detected and quantified using a frequency analysis in patients featuring intention tremor. These preliminary results illustrate the feasibility of using the VPIT with MS patients, and underline the potential of this test to evaluate upper limb motor function and discriminate characteristic MS related impairments.