Dystonia is a disabling movement disorder that manifests with sustained co-contraction of agonist and antagonist muscles, giving rise to abnormal twisted postures and overflow of muscle activity. Abnormal neurophysiologic parameters of the somatosensory and motor cortex have been demonstrated, although it is unclear how these changes lead to the predominant motor manifestations. In normal voluntary movement, communication between sensory and motor cortices is important and these interactions may be dysfunctional in dystonia. Coherence is a powerful method used to assess brain communication and has been instrumental in demonstrating the interregional interactions involved in normal movement. Inappropriate connectivity in terms of the duration of communication or the extent of spread over sensorimotor areas may give rise to the involuntary overflow of movements that characterize dystonia. We propose to examine changes in coherence associated with disorganized movements to yield insight as to the brain networks involved in the development and expression of the disease.