Focal dystonia is an irregular movement disorder specific to one part of the body. In dystonia, muscle contractions cause irregular movements, twitches, tics, and twisted or repetitive postures which may be sustained or intermittent.
Focal dystonia can be treated. If you suspect you have this condition, contact your doctor.
The most common types of focal dystonia are:
- Blepharospasm (an eye twitch) – affecting the eyes
- Cervical dystonia – affecting the neck
- Miege syndrome – affecting the eyes and face
- Oromandibular dystonia – affecting the jaw
- Spasmodic dysphonia – affecting the vocal cords
- Axial dystonia – affecting the trunk
- Dystonia of the arm (eg, writer’s cramp)
Dystonias are caused by an abnormality in the basal ganglia of the brain, which is where messages that initiate muscle contractions are processed. Factors that may cause focal dystonia include:
- Birth injury (eg, lack of oxygen)
- Infection
- Reactions to medications
- Heavy metal poisoning
- Carbon monoxide poisoning
- Trauma
- Stroke
- Other diseases
- Inherited abnormalities of the basal ganglia
The following factors increase your chance of developing focal dystonia. If you have any of these risk factors, tell your doctor:
If you experience any of these symptoms do not assume focal dystonia is the cause. These symptoms may be attributed to other, less serious health conditions. If you experience any one of them, see your physician.
- Eyelid spasms
- Rapid or uncontrollable blinking of both eyes
- Neck twisting
- Difficulty handwriting
- Foot cramps
- Pulling or dragging of a foot
- Tremor
- Voice or speech difficulties
Your doctor will ask about your symptoms and medical history, and perform a physical exam. Your doctor may refer you to a speech-language pathologist, physical or occupational therapists, and/or genetic counselors.
Tests may include the following:
- A careful family history
- Blood tests
- Urine tests
- Cerebrospinal fluid tests
- Genetic tests
- Electromyography
– to determine the health of the muscles and nerves
- Electroretinography – to measure the retina’s response to light stimulation
- Electroencephalography
– a test that records the brain’s activity by measuring electrical currents through the brain. This test is used to detect or rule out seizures.
-
Skin, muscle, and/or nerve tissue
biopsies
- Eye examination
- Neurologic evaluation – to rule out other neurological disorders
- CT scan
or
MRI
– two types of x-rays that use a computer (CT) or magnetic waves (MRI) to view the structures of the brain
Talk with your doctor about the best treatment plan for you. Treatment options include the following:
Certain medications may help correct imbalances in neurotransmitters, reducing symptoms of focal dystonia. Medications used to treat dystonia include:
- Trihexyphenidyl
- Benztropine
- Procyclidine HCl
- Muscle relaxants
- Levodopa/carbidopa
- Bromocriptine
Anticonvulsant medications may also help people with dystonia. Since these medications are associated with certain side effects, your physician will balance treating your symptoms with reducing the risk of side effects.
Injecting botulinum toxin (eg, Botox) directly into the muscles affected by dystonia can weaken the muscle. This may help improve symptoms of dystonia for 3-4 months.
Surgery to cut the nerves leading to muscles affected by dystonia or removing the muscles altogether may help reduce dystonic muscle contractions. In addition, surgery to destroy the small area within the brain that dystonia originates from may successfully stop or reduce the disorder.
There is no known way of preventing focal dystonia. To help reduce your chances of getting this condition, take steps to reduce your risk of infection, stroke, trauma, and carbon monoxide or heavy metal poisoning. In addition, if you take any of the following medications, talk with your doctor about your risk of developing dystonia as a side effect:
- Levodopa
- Bromocriptine
- Antipsychotics
- Metoclopramide
- Dilantin
- Calcium channel blockers
- Selective serotonin reuptake inhibitors
- Ergotamines
- Antihistamines
