Efficacy of Levetiracetam in Oromandibular and Cranial Dystonia

Background: \- People with dystonia cannot control their muscle contractions. This disorder can affect different body areas. When it affects the face, tongue, and jaw, it is called oromandibular dystonia (OMD) or cranial dystonia (CD). Researchers want to find out if a drug that treats seizures may help people with this kind of dystonia. Objective: \- To see if levetiracetam can improve symptoms of jaw or face dystonia. Eligibility: \- Adults ages 18 to 80 years with OMD or CD. Design: * Participants will be screened with a medical history and physical exam. Researchers will test how severe their dystonia is. * Participants will have blood drawn through a needle in the arm. * Participants will be assigned to take either levetiracetam or placebo. * Phase 1: * Participants will start with one 500-mg tablet twice daily. The dose will be increased by 500 mg every 3 days. The maximum dose will be 4000 mg a day over 3 weeks. Participants who cannot tolerate that will take the highest dose they can. * Participants will return for study visits at weeks 3 and 6. They will be asked about their health, side effects, and symptoms of depression. They will have a neurological examination and test of their dystonia. * After the week 6 visit, participants will taper and stop the study drug over about 1 week. * Phase 2 begins one week later. Participants will repeat phase 1, but with the other drug. * After phase 2, participants will return to their usual clinics. They will be told how to stop taking the drug. They will have a follow-up phone call 2 weeks later.