LAUSR

Primary dystonias are rare disorders characterized by involuntary, sustained muscle contractions that cause twisting movements and abnormal postures. Clinical presentation is variable and it also includes adult-onset focal dystonia (FD), in which only one region of the body is affected. Cervical dystonia is the most common form of FD, followed by blepharospasm, oromandibular dystonia, laryngeal dystonia, and limb dystonia (writer's cramp).1,2 From Oppenheimer's classic description of generalized dystonias in 1911 to the first international dystonia symposium in 1975, Fahn and Eldridge's first definition and classification for dystonias, and Marden's definition of FD in 1976, the pathophysiology has been and remains obscure.2 The neuroanatomical basis for dystonia has changed substantially from the previous concept of isolated dysfunction of basal ganglia to the most recent thinking that dystonia is a “network disorder” resulting from dysfunction in multiple and varied areas of the brain including the cerebellum, prefrontal cortex, midbrain, motor cortex, and somatosensory cortex.3 Dystonia (including FD) is currently considered a disorder of the large-scale structural functional connectome.4