Definition

Dystonia is a movement disorder characterized by twisting, repetitive movements caused by involuntary contraction and spasm of muscles, which results in abnormal, often painful postures.

Causes

The causes of many cases of dystonia are unknown.

Primary or idiopathic dystonia patients exhibit no obvious structural brain abnormalities and relate no history of serious illness.

  • Communication problems between nerve cells located in the basal ganglia — an area of the brain involved in initiating muscle contractions.
  • Genetic abnormalities including the DYTI mutation prevalent in the Ashkenazi Jewish population and the DYT6 mutation prevalent in the Amish.

Secondary or symptomatic dystonia often has an identifiable cause:

  • Traumatic brain injury
  • Static Encephalopathy
  • Stroke
  • Brain tumor
  • Oxygen deprivation
  • Infections, such as tuberculosis or encephalitis
  • Reactions to certain drugs
  • Heavy metal or carbon monoxide poisoning
  • Diseases of the nervous system
  • Task related factors

Risks

Risk factors are things associated with an increased chance of developing a disease or condition. Genetic mutations, brain injury of any sort and infections are all risk factors, but dystonia is an uncommon disorder, affecting less than 1 percent of the population.

Symptoms

  • Generally develop gradually
  • Repetitive, patterned, and often twisting involuntary muscle contractions
  • Muscle spasms
  • Painful cramping
  • May occur with a specific action
  • May affect one body part (focal dystonia); two adjacent body parts (segmental dystonia); or multiple body parts (generalized dystonia)

Diagnosis

  • A neurologist or movement disorder neurologist takes a complete medical and family history and performs a physical examination
  • Laboratory studies including blood or urine tests and analysis of cerebrospinal fluid
  • Genetic testing when indicated
  • Electrical sensors (EMG) inserted into affected muscle groups
  • MRI to identify tumors, lesions or evidence of stroke

Treatment

  • Oral medications such as anticholinergics (eg. Artane), oral baclofen, benzodiazepines, and tetrabenzine have been used for years with modest results.
  • A small subset of patients with “dopa-responsive dystonia” respond profoundly to levodopa.
  • Local injections of botulinum toxin (BotoxTM) can alleviate focal dystonias such as writer’s cramp, blepharospasm, or torticollis, but this intervention is impractical in patients with generalized symptoms.
  • Surgical interventions in which specific targets within the basal ganglia are destroyed have been moderately successful, but often result in severe and irreversible adverse neurologic events.
  • Deep brain stimulation has revolutionized the treatment of dystonia.
    • The effects are reversible
    • Stimulation parameters can be customized for each patient, maximizing therapeutic results
    • Bilateral procedures are safer than neuroablation
    • Because brain tissue is not destroyed, the application of future therapies is not precluded

Prevention

Currently, dystonia can not be prevented.

The Mount Sinai Health System has been a pioneer in the surgical treatment of torsion dystonia, employing Deep Brain Stimulation Therapy in one of the largest series of dystonia patients in the world. The results have been impressive overall and nothing short of spectacular in some cases.

If you want to learn more about dystonia, call the Mount Sinai Department of Neurosurgery at 212-241-2377.