The efficacy of botulinum toxin (BTX) has now been demonstrated for a variety of diseases associated with involuntary muscle spasms or movement. The application of botulinum toxin therapy to movement disorders requires treatment tailored to the individual patient and specific techniques of injection. This protocol 1) provides for training of physicians in the use of botulinum toxin and 2) allows us to provide botulinum toxin injections for patients participating in other studies on the physiology of sensorimotor systems and physiological effects of botulinum toxin. Patients can be in the study at any one time either for the teaching value or for participation in other protocols, or both.