Table 1.

Classification of dystonia (1).

(A) CLINICAL CHARACTERISTICS OF DYSTONIA

Age of onset (infancy, childhood, adolescence, and early/late adulthood)

Body distribution

Focal (only one body region is affected. e.g., blepharospasm)

Segmental (two or more contiguous body regions are affected)

Multifocal (two non-contiguous or more – contiguous or not – body regions are involved)

Hemidystonia (more body regions restricted to one body side are involved)

Generalized (involvement of the trunk and at least two other sites, including leg or not)

Temporal pattern

Course of disease (static or progressive)

Variability

Persistent (appears to approximately the same extent throughout the day)

Diurnal (recognizable circadian variations in occurrence, severity and phenomenology)

Action-specific (occurs only during a particular activity or task)

Paroxysmal (sudden self-limited episodes of dystonia usually induced by a trigger)

Associated features

Isolated dystonia (dystonia is the only sign, with the exception of tremor)

Combined with other movement disorders (e.g., myoclonus)

Associated with other neurological symptoms (e.g., cognitive decline) or systemic manifestations (e.g., Wilson disease)

(B) ETIOLOGY

Nervous system pathology

Evidence of degeneration

Evidence of structural (often static) lesions

No evidence of degeneration or structural lesion

Inherited or acquired

Inherited (autosomal dominant, autosomal recessive, X-linked recessive, and mitochondrial)

Acquired (brain injury, infection, drug, toxic, vascular, neoplastic, and psychogenic)

Idiopathic (sporadic and familial)