Dystonias are movement disorders in which sustained muscle contractions force the body into twisting or repetitive movements, or unusual postures. These movements are involuntary and can affect any part of the body. Dystonias are sometimes progressive, meaning they become worse over time, and can significantly impact a patient’s quality of life.

Dystonia can be classified in many ways. For example, focal dystonias affect just one part of the body whereas generalized dystonias have more widespread effects. Some other types include:

• Cervical dystonia (spasmodic torticollis). The most common focal dystonia, it affects the muscles of the neck that control the position of the head.
  
  
• Blepharospasm. Involuntary closing of the eyelids.
  
  
• Dopa-responsive dystonia (DRD). Marked by difficulty walking (which results in stiff-legged gait) and spasticity.
  
  
• Spasmodic dysphonia. This focal dystonia affects the vocal cords and speech.
  
  
• Torsion dystonia. A rare, generalized dystonia that often gets progressively worse and may require the patient to use a wheelchair.

Experts believe that many dystonias are caused by an abnormality in a region of the brain called the basal ganglia. Some of the messages that cause muscles to contract are processed in the basal ganglia, which plays a major role in controlling movement and preventing unwanted movement. Some dystonias result from genetic factors, whereas others are the result of disease, injury to the brain or adverse side effects from certain medications. The cause of dystonias sometimes is not known.

Symptoms of a dystonia may affect many different parts of the body. In some cases, a single muscle is affected. In other cases, symptoms may appear in a group of muscles or throughout the body. Because dystonias can impact many different types of muscles, symptoms also tend to vary widely.

Dystonias may be difficult to diagnose because they can resemble other medical conditions. In diagnosing a dystonia syndrome, a physician will pay special attention to events or illnesses that may be associated with the onset of dystonia. Physicians will also examine the patient for classic signs of dystonias.