Impaired Short-term Motor Learning in Multiple Sclerosis: Evidence From Virtual Reality

Objective. Virtual reality (VR) has been proposed as a potentially useful tool for motor assessment and rehabilitation. The objective of this study was to investigate the usefulness of VR in the assessment of short-term motor learning in multiple sclerosis (MS). Methods. Twelve right-handed MS patients and 12 control individuals performed a motor-tracking task with their right upper limb, following the trajectory of an object projected on a screen along with online visual feedback on hand position from a sensor on the index finger. A pretraining test (3 trials), a training phase (12 trials), and a posttraining test (3 trials) were administered. Distances between performed and required trajectory were computed. Results. Both groups performed worse in depth planes compared to the frontal ( x, z) plane ( P < .006). MS patients performed worse than control individuals in the frontal plane at both evaluations ( P < .015), whereas they had lower percent posttraining improvement in the depth planes only ( P = .03). Conclusions. The authors' VR system detected impaired motor learning in MS patients, especially for task features requiring a complex integration of sensory information (movement in the depth planes). These findings stress the need for careful customization of rehabilitation strategies, which must take into account the patients' motor, sensory, and cognitive limitations.