Cervical dystonia (CD) is the most common focal dystonia. Currently there are no effective oral medications for the treatment of CD. While botulinum toxin injections improve symptoms, they require repeated injections by a trained physician and some patients stop responding to injections or never respond at all. Therefore, alternative treatment options for CD are needed. One new agent is a drug that targets glutamate receptors that are thought to be involved dystonia. This drug, perampanel, was originally developed for epilepsy and is licensed for use in the USA and Canada for treating epilepsy. The purpose of this study is to test the effectiveness of perampanel in treating the symptoms of CD.