The Effects of Repetitive Paired Associative Stimulation in Dystonia

Study Summary

Background: \- People with dystonia have serious muscle contractions that cause abnormal movements or postures. This significantly affects their daily lives. The common type is called organic. The other type is psychogenic. People with this type have typical symptoms plus some psychological effects. Researchers will look at how rapid transcranial magnetic stimulation (rTMS) of the brain combined with stimulation of a nerve affects the ability to detect sensations. They will compare the responses of people with different types of dystonia. They will also compare the responses of people with dystonia to responses of people without it. This study may help us learn more about the nature of different types of dystonia. Objectives: \- To see whether TMS combined with nerve stimulation affects the brain differently in people with different types of dystonia and those without dystonia. Eligibility: * Individuals at least 18 years old, who are right-handed and have dystonia. * Healthy volunteers at least 18 years old. Design: * Participants will have two clinical visits. Each visit will be a few hours long. They can be done on the same day. * Participants will be screened with a medical history and physical exam. * Participants will take several sensory tests. For these tests, electrodes will be placed on their skin. The participants will feel small electric shocks during some of the tests. * Participants will undergo TMS. For 2 minutes, quick electrical currents will pass through a wire coil placed on their head. As this happens, researchers will ask the participants to move certain muscles.