Generalized dystonia is dystonia that affects the trunk and at least two other parts of the body. It usually begins in childhood or adolescence, often in one leg or arm, and spreads over months or years. A large share of early-onset cases are genetic; the best-known cause is a mutation in the TOR1A gene (DYT1 dystonia).
For disabling generalized dystonia that medicines do not control, deep brain stimulation of the globus pallidus is the most effective treatment available. In a prospective multicenter study published in the New England Journal of Medicine, movement scores improved by 51% on average after one year,[1] and a meta-analysis of genetic dystonias found a 68% average motor improvement in DYT1 (TOR1A) patients.[2]
Symptoms of generalized dystonia
- A foot or hand that twists during walking or writing, often the first sign in children
- Bending or twisting of the trunk and neck
- Difficulty walking, sitting, dressing and eating
- Speech and swallowing problems in some genetic forms
- Pain and, in long-standing cases, fixed joint deformities
What causes generalized dystonia?
- Genetic (inherited) dystonia. TOR1A (DYT1), THAP1 (DYT6), KMT2B (DYT28) and other genes. See genetic dystonia and DBS.
- Idiopathic. No cause is found, but MRI is normal and the dystonia is isolated.
- Acquired. Birth injury (dyskinetic cerebral palsy), metabolic disorders, brain injury or tardive dystonia.
Every young person with dystonia should have a supervised medication trial to exclude dopa-responsive dystonia (DYT5), which is controlled by medication and does not need surgery.
Why early treatment matters
A meta-regression of individual patient outcomes found that, in primary generalized dystonia, shorter disease duration and younger age at surgery were associated with better results after DBS.[3] In TOR1A dystonia, a longer duration of dystonia was linked to a smaller motor improvement.[2] Long-standing dystonia can lead to fixed joint and spine deformities that stimulation cannot reverse, so evaluation should not be delayed until every medicine has been tried for years.
How DBS treats generalized dystonia
Thin electrodes are placed in the globus pallidus internus (GPi) on both sides of the brain and connected to a pacemaker-like stimulator under the skin of the chest. Stimulation calms the abnormal signals that drive the contractions. In dystonia, the benefit builds gradually over weeks and months. Full details are on treatment for generalized dystonia.
Frequently asked questions
Can children have DBS for generalized dystonia?
Yes. In centers worldwide DBS is used in both children and adults with generalized dystonia, and age alone is not a barrier. Whether DBS is right for a particular child is decided case by case after a full evaluation.
Is generalized dystonia always genetic?
No. Many cases are genetic, especially with early onset, but some are idiopathic or acquired. Genetic testing helps predict the response to DBS.
Sources
- Vidailhet M, Vercueil L, Houeto JL, et al. Bilateral deep-brain stimulation of the globus pallidus in primary generalized dystonia. N Engl J Med. 2005;352(5):459–467. Source
- Artusi CA, Dwivedi A, Romagnolo A, et al. Differential response to pallidal deep brain stimulation among monogenic dystonias: systematic review and meta-analysis. J Neurol Neurosurg Psychiatry. 2020;91(4):426–433. 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
- Vidailhet M, Vercueil L, Houeto JL, et al. Bilateral, pallidal, deep-brain stimulation in primary generalised dystonia: a prospective 3 year follow-up study. Lancet Neurol. 2007;6(3):223–229. Source