What is focal dystonia?
Dystonia is a condition that causes involuntary or unusual movements.
There are several different types of dystonia. Focal dystonia affects a single body part, which is usually the fingers or hands. Additional names doctors may call focal dystonia include:
- focal hand dystonia
- focal task-specific dystonia
- occupational cramp/dystonia
- task-specific dystonia
Dystonia that occurs in athletes is known as the “yips.”
Musicians experience the greatest incidence of focal dystonia. An estimated 1 to 2 percent of all professional musicians experience focal dystonia. Men are also more likely than women to experience focal dystonia.
Dystonia is also common in:
- hair stylists
- people who type on the computer for most their day
Focal dystonia can commonly occur at several different areas of the body. Examples of focal dystonia types and symptoms include:
- blepharospasm: eye twitching
- cervical dystonia: when the neck muscles spasm or cause the neck to tilt in an unusual fashion, otherwise called torticollis
- oromandibular dystonia: a clenching or locking of the jaw muscles
- spasmodic dysphonia: when the vocal cords do not work appropriately and a person may have difficulty making certain sounds
If a musician has focal dystonia, they may find that their hands don’t respond as intended when they try to play an instrument.
Examples of the symptoms include:
- fingers that curl or clench
- hands that “freeze” or stop moving altogether
- fingers that shake
Usually, the fingers most affected are the fourth and fifth fingers.
Focal dystonia is the result of changes in the way the nerves of the body parts communicate with the brain. As a result, instructions from the brain do not correspond with the desired movements. The Dystonia Medical Research Foundation likens the affected nerve transmission to a “computer virus” or “hard drive crash” of a person’s internal programming and movements.
Many causes of focal dystonia are primary, which means a doctor can’t identify an underlying medical condition that’s causing the focal dystonia. However, some types of focal dystonia are secondary. This means a person can link their focal dystonia to a medical condition or cause. Examples could include:
- trauma to the affected body part
- adverse reaction to medication
- carbon monoxide poisoning
- Parkinson’s disease
Musicians that experience focal dystonia may be able to link the cause back to a change in their habits, such as:
- increased amount of practice or performance time
- change in technique
- changes made because of a nerve injury
- playing a new type of instrument
Environmental factors and genetic background may both play a role in a person’s focal dystonia. However, researchers haven’t identified a specific gene or genes that causes focal dystonia. An estimated 10 percent of people with focal dystonia have a family history of the condition.
At your appointment, your doctor will ask about your medical history, activities, and medications that you take. They will also perform an examination of the affected body part.
The symptoms of focal dystonia can often mimic those of overuse injuries, such as carpal tunnel. However, focal dystonia occurs as a result of changes in the brain, not injuries to the nerves or hands. Sometimes focal dystonia can be misdiagnosed as an overuse injury.
Your doctor will try to rule out nerve entrapment and overuse injuries as the causes of your symptoms.
They may order several tests including:
- blood tests to look for signs of infection
- electromyography to monitor the electrical activity in your muscles
- an MRI or CT scan to look for tumors or lesions on your brain
Focal dystonia affects the sensory processing information the brain uses to perform movements. Small changes in the way a person holds an instrument or a change in texture under the fingertips can reduce the incidence of focal dystonia.
For example, a guitarist with focal dystonia may find relief from their symptoms by wearing a thin glove while playing.
Another approach could be changing the angle of a computer keyboard. Some pianists may find they can play on an electric keyboard instead of a traditional piano because the keys have a slightly different texture.
Stretching the affected areas can help to reduce discomfort associated with focal dystonia. Consult a physical therapist to determine the best and safest exercises for your focal dystonia type.
There is no current cure for focal dystonias, either through medical or at-home treatments. However, there are some treatment approaches that have been met with success. These include taking medications known as anticholinergics. Doctors may prescribe a medication called Artane (trihexyphenidyl), an anticholinergic. This medication helps to block nerve transmissions to the affected muscles. However, they can cause side effects that include dry mouth and difficulty urinating. Other medications, such as tetrabenazine, could also be used, but side effects include drowsiness, anxiety, or depression.
Injections of botulinum toxin (BOTOX) can help to subtly weaken the affected muscles of the hand. This may help reduce the incidence of dystonia-related spasms.
In severe cases, your doctor might recommend surgical procedures. Surgical procedures for focal dystonia include:
Deep brain stimulation
Electrodes are implanted on the part of the brain that controls the affected muscles. These electrodes are connected to a generator that is implanted in your chest. The generator emits electrical signals to help control muscle contractions.
Selective denervation surgery
This surgery would be reserved for people who have not been able to manage their symptoms with any other treatment. In this procedure, the nerves that control the muscle spasms would be cut.
A person’s focal dystonia can spread to other parts of the body. Segmented dystonia affects two contiguous body parts. Multifocal dystonia affects many body parts. An estimated
Doctors know focal dystonia most commonly affects certain populations, such as musicians. However, they have difficulty predicting exactly who could be affected because they don’t understand what causes it. But they do know certain factors can make dystonia worse. These include:
- extreme stress
- excessive talking
- excessive agitation
Avoidance of these extremes may help to manage the condition and prevent dystonia from becoming worse.