Basal Ganglia and Related Structures Basal Ganglia and Related Structures Disorders of Function Dystonia and Tics Dystonic movements are sustained involuntary movements of the axial or limb musculature. They are slow and writhing and produce abnormal postures and painful muscle spasm. Some consider dystonia to be is an extreme form of athetosis.
Tics are spasmotic movements similar to chorea in form.
They differ from choreiform movements, however, in that they are usually the same movement endlessly repeated.