Segmental dystonia is dystonia that affects two or more body regions that are next to each other, for example the face and neck, or the neck and one arm. Many patients call it regional dystonia. The best-known form is Meige syndrome, in which eyelid spasm (blepharospasm) is combined with dystonia of the lower face and jaw.
Segmental dystonia often begins as a focal dystonia that spreads to the neighbouring region over months or years. It responds well to pallidal deep brain stimulation: patients with segmental dystonia were included in the landmark sham-controlled trial published in the New England Journal of Medicine, in which stimulation improved movement scores far more than sham stimulation.[1]
Common patterns of segmental dystonia
- Cranial segmental dystonia (Meige syndrome). Eyelids plus lower face, jaw, tongue or throat.
- Cranio-cervical dystonia. Face or jaw plus neck. Common in adults and in DYT6 (THAP1) dystonia.
- Cervico-brachial dystonia. Neck plus shoulder and arm.
- Axial dystonia. Neck plus trunk, causing the body to bend forward, sideways or backward.
Why it matters that dystonia is segmental
Botulinum toxin works best when a few muscles are involved. When dystonia spreads across several regions, the number of muscles and the total dose needed rise, and injections become less practical. This is the point where many patients and their doctors start to consider deep brain stimulation, which treats all affected regions at once from the brain.
Does DBS work for segmental dystonia?
Yes. In the randomized trial by Kupsch and colleagues, 40 patients with primary generalized or segmental dystonia were randomly assigned to pallidal stimulation or sham stimulation for 3 months. The movement score improved by 15.8 points with stimulation and by 1.4 points with sham.[1] Follow-up of the same trial showed the benefit was maintained at 5 years.[2] Treatment details are on treatment for generalized and segmental dystonia.
Frequently asked questions
Is segmental dystonia worse than focal dystonia?
It involves more muscles, so it is often harder to control with injections alone. It is not necessarily progressive, and it can respond very well to DBS.
Is Meige syndrome segmental dystonia?
Yes. Meige syndrome is cranial segmental dystonia: it involves the eyelids and the lower face or jaw.
Sources
- Kupsch A, Benecke R, Müller J, et al. Pallidal deep-brain stimulation in primary generalized or segmental dystonia. N Engl J Med. 2006;355(19):1978–1990. doi:10.1056/NEJMoa063618 Source
- Volkmann J, Wolters A, Kupsch A, et al. Pallidal deep brain stimulation in patients with primary generalised or segmental dystonia: 5-year follow-up of a randomised trial. Lancet Neurol. 2012;11(12):1029–1038. Source