What is Focal Dystonia?
Dystonia is a movement disorder in which muscles contract involuntarily, causing repetitive or twisting movements; focal dystonia is where the conditions affects one part of the body only. It may also be referred to as focal hand dystonia, focal task-specific dystonia, or occupational cramp/dystonia.
Typically, focal dystonia occurs during a specific action or activity (i.e. typing, playing an instrument, writing, manipulating a dental instrument) and worsens with stress, fatigue or anxiety. While most of hand dystonia is isolated dystonia, it may occur in conjunction with early onset generalized dystonia (about 16% of primary focal hand dystonia spread proximally or contralaterally or become generalized within 8 years).
While focal dystonia can mimic symptoms of overuse injuries (e.g. carpal tunnel syndrome), it actually occurs as a result of changes to how the nerves communicate with the brain, not injuries to the nerves or hands.
What are the Symptoms of Focal Dystonia?
Symptoms, specifically in the hands, can include:
- Early signs are often mild, occasional and linked to a specific activity (e.g. playing a musical instrument), and may only be noticeable after prolong exertion, stress or fatigue.
- Involuntary muscle contractions, including in the fingers, hand, forearm and sometimes shoulder.
- Fingers that clench or curl
- Hands that freeze or stop moving
- Fingers that shake
- Physical disabilities that affect performance of everyday activities or specific tasks
- Pain and fatigue (due to the constant contraction of muscles)
- Permanent malformations (if muscle spasms lead to the constriction of tendons)
- Depression, anxiety and withdrawal
- Median and ulnar nerve entrapments are common in dystonia patients
What Causes Focal Dystonia?
The exact cause isn’t known but it may involve altered nerve-cell communication in several regions in the brain, including the basal ganglia. While the theory is that neurotransmitters are abnormal in people with dystonia, it doesn’t affect intelligence, ability to think or mental health issues.
It can also be a sign of another disease, including Parkinson’s, traumatic brain injury, stroke, brain tumor or disorders that develop in some individuals with cancer, infections, heavy metal poisoning, or reactions to certain medications.
How is Focal Dystonia Diagnosed?
- Blood, urine or cerebrospinal fluid tests (to reveal signs of toxins or other conditions)
- MRI or CT scan (to look for abnormalities in the brain such as tumors, lesions, or stroke)
- EMG or EEG
- Genetic testing (5-25% of those with focal dystonia have a family history)
What is the Treatment for Focal Dystonia?
Focal dystonia is typically treated by a neurologist who specializes in movement disorders and treatments can include:
- Small changes to the way a task is carried out (e.g. writing with a thicker pen or holding a musical instrument differently)
- Physical and occupational therapy
- Surgery (including deep brain stimulation and selective denervation surgery)
Focal dystonia can interfere with an individual’s ability to work or carry out daily tasks. If you have been diagnosed with focal dystonia and are worried that it may be impeding your ability to continue to safely practice on patients, you should speak with an experienced disability insurance attorney.
These posts are for informative purposes only and should not be used as a substitute for consultation with and diagnosis by a medical professional. If you are experiencing any of the symptoms described above and have yet to consult with a doctor, do not use this resource to self-diagnose. Please contact your doctor immediately and schedule an appointment to be evaluated for your symptoms.
Diego Torres-Russotto, MD & Joel S. Perlmutter, MD, Focal Dystonias of the Hand and Upper Extremity, J Hand Surgy Am. 2008 Nov: 33(9): 1657-1658
Dystonia Medical Research Foundation
National Institute of Neurological Disorders and Stroke
Medline Plus (National Library of Medicine)