25A. Focal dystonias

Definition and types

A dystonia is a movement disorder with sustained or intermittent muscle contractions causing abnormal movements or postures. It can be focal, segmental, or generalised, it can be early-onset or late-onset, and it can be primary or secondary.

There are many types of focal dystonia, depending on the affected body part:

  • Cervical dystonia (= torticollis)
    • Sudden, painful contraction of sternocleidomastoid causing the head to turn, tilt, or flex
  • Hand dystonia (= writer’s cramp)
    • Non-painful contractions in the hand or arm which occur when writing
  • Eye dystonia (= blepharospasm)
    • Spasm of periocular muscles, causing involuntary twitching or blinking
  • Oromandibular dystonia
    • Spasm of muscles of mouth and jaw, causing chomping movements
  • Hemifacial spasm
    • Spasm of half the face

Treatment of focal dystonias

The main treatment of focal dystonias is botulinum toxin injection into the affected muscle. This is very effective.

In case botulinum toxin injection is insufficient, deep brain stimulation may be used.


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25B. Creutzfeldt-Jakob disease (CJD)

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