Classification of Dystonias Dystonias are classified based on Etiology Clinical features Etiology is categorized as Inherited: Has a proven genetic origin (previously known as primary) and includes disorders with autosomal dominant, autosomal recessive, mitochondrial or X-linked inheritance Idiopathic: Can be familial or sporadic Acquired: Associated with neuroanatomic abnormalities due to other disorders or drugs Clinical features include the following: Onset: Can occur at any age, from infancy to late adulthood Body distribution: May be focal (limited to one body part), segmental (involving ≥ 2 more contiguous body parts, such as the upper and lower face or face and neck), multifocal (involving ≥ 2 noncontiguous body parts, such as the neck and leg), generalized (involving the trunk plus 2 different body parts), or hemicorporal (involving half the body; also called hemidystonia) Temporal pattern: May be static, progressive, paroxysmal, or persistent and may have diurnal variability or be triggered by certain tasks (task-specific dystonia) Isolated (no evidence of another movement disorder) or combined (accompanied by other involuntary movements [other than tremor], but predominantly dystonia) Cervical dystonia (spasmodic torticollis) —involuntary contractions of the neck muscles—is the most common dystonia.