For patients with multiple sclerosis and spinal cord injury, virtual reality systems provide new methods of assistance with dysmetria, tremor, spasticity, and weakness. Robust mechanisms exist within the central nervous system to produce neuroplastic adaptive responses operative in retraining motor activities. Haptic systems cued by the patient's visual environment can produce force corridors to guide a patient's wrist and hand in the performance of specific tasks. Such haptic application can substantially reduce motor instability and improve performance. Preliminary clinical approaches, using video tremor tracking and manual force application, indicate the extent of the expected improvements attainable with this approach. Refinement of these techniques is proceeding to development of VR systems that will allow more extensive application to the problems of dysmetria, more general instances of tremor, spasticity, and weakness.