Dystonia is classified on two axes: what it looks like (body distribution, age at onset, time course and associated features) and what causes it (inherited, acquired or idiopathic). By body distribution there are five types: focal (one region), segmental (neighbouring regions), multifocal (separate regions), generalized (trunk plus two other regions) and hemidystonia (one side of the body).
The classification is not just a label. It tells the specialist which tests to order and which treatment fits. For deep brain stimulation, the most useful distinction is whether the dystonia is isolated and inherited or idiopathic, which usually responds very well, or acquired from brain injury, which responds less predictably.[1][2]
Types by body distribution
Focal dystonia
One body region is affected. The common forms are cervical dystonia (neck), blepharospasm (eyelids), oromandibular dystonia (jaw, mouth, tongue), laryngeal dystonia or spasmodic dysphonia (voice), and limb dystonia such as writer’s cramp or musician’s dystonia. Focal dystonia usually begins in adulthood. More on focal dystonia.
Segmental dystonia
Two or more neighbouring regions are involved. The best-known example is Meige syndrome, where blepharospasm is combined with dystonia of the lower face and jaw (cranial segmental dystonia). Another is cranio-cervical dystonia, where the face and neck are both affected. Some patients call this “regional dystonia”. More on segmental dystonia.
Multifocal dystonia
Two or more regions that are not next to each other are involved, for example the neck and one leg.
Generalized dystonia
The trunk and at least two other regions are affected, with or without the legs. Generalized dystonia usually begins in childhood or adolescence and is often genetic. More on generalized dystonia.
Hemidystonia
One side of the body is affected. It almost always points to an acquired lesion in the opposite side of the brain, such as a stroke, and is investigated with MRI.
Types by age at onset
The 2013 consensus groups onset into infancy (birth to 2 years), childhood (3–12), adolescence (13–20), early adulthood (21–40) and late adulthood (over 40).[1] Early onset is more often genetic and more likely to spread. Late onset is usually focal and stays focal.
Types by time course
- Static or progressive. Most adult focal dystonias progress for a few years and then stabilise.
- Persistent, action-specific, diurnal or paroxysmal. Writer’s cramp appears only during writing. Some genetic forms fluctuate during the day or come in attacks.
Isolated or combined dystonia
Isolated dystonia means dystonia is the only movement problem, apart from tremor. Combined dystonia means it comes with another movement disorder, such as myoclonus (myoclonus-dystonia, DYT11), parkinsonism or chorea. This distinction replaced the older words “primary” and “secondary” in the scientific literature, although patients and many doctors still use them.
Types by cause
| Cause group | Meaning | Examples | Typical DBS response |
|---|---|---|---|
| Inherited | Proven genetic cause | TOR1A (DYT1), THAP1 (DYT6), SGCE (DYT11), KMT2B (DYT28) | Often very good; varies by gene |
| Idiopathic | No cause found | Most adult cervical dystonia and Meige syndrome | Good |
| Acquired | Known brain injury or exposure | Dystonic cerebral palsy, stroke, trauma, tardive dystonia | Less predictable; tardive dystonia is the exception and responds well |
See primary vs secondary dystonia for the outcome data behind this table.
Frequently asked questions
What is the most common type of dystonia?
Focal dystonia is the most common type in adults, and cervical dystonia is the most common focal dystonia.
What is the difference between segmental and generalized dystonia?
Segmental dystonia involves two or more neighbouring body regions, such as the face and neck. Generalized dystonia involves the trunk and at least two other regions. Both can be treated with DBS when they are disabling.
Is regional dystonia the same as segmental dystonia?
Yes. “Regional dystonia” is an everyday term for dystonia that affects one connected area of the body, which doctors call segmental dystonia.
Can focal dystonia become generalized?
In adults it rarely does. Focal dystonia that starts in childhood, especially in the leg or arm, has a higher chance of spreading.
Sources
- Albanese A, Bhatia K, Bressman SB, et al. Phenomenology and classification of dystonia: a consensus update. Mov Disord. 2013;28(7):863–873. Source
- Andrews C, Aviles-Olmos I, Hariz M, Foltynie T. Which patients with dystonia benefit from deep brain stimulation? A metaregression of individual patient outcomes. J Neurol Neurosurg Psychiatry. 2010;81(12):1383–1389. Source