People with dystonia experience involuntary muscle spasms or contractions. These result in twisting or jerking movements, and unusual body positions/postures. Dystonia can affect almost any part of the body, however, only one area is often affected. 

The common presentations are:
• Neck muscle contractions lead to abnormal head turning, tilting or twisting, often combined with shaking or jerking movements referred to as cervical dystonia aka torticollis.

• Facial muscle contractions resulting in excessive blinking or eye lid spasms, called blepharospasm. When this occurs together with lower facial spasms, it is referred to as Meige syndrome. Involuntary muscle spasms or contractions of the jaw and/or tongue are known as oromandibular dystonia.
• When these involuntary contractions involve the vocal cords – the voice becomes strained and breathy referred to as spasmodic dysphonia or laryngeal dystonia.
• Other commonly affected areas include the hand or foot. Sometimes the dystonia is associated with specific activities (task-specific dystonias) such as when writing in writer’s cramp or when playing a musical instrument such as in guitarist or violinist dystonia.
• Dystonia can be generalized (affecting whole body or several body areas) – more common with childhood onset, focal (neck, hand, eyelids, jaw) or just one side of the body (hemi-dystonia).

Please visit the following sites for more information:

Dystonia Fact Sheet (NINDS)

Dystonia UK