Patients enrolled in the study also will be evaluated by a physiatrist and physical and occupational therapists. They will be examined for muscle stiffness and reflexes. Their gait and movements (e.g., how they pick up a glass of water) will be evaluated. They will be asked about their ability to perform activities around the house and at school and whether a wheelchair or walker is needed to get around. Patients may also be asked about how they are dealing with their movement problems and how it affects their caregivers.