What to know about focal dystonia
The disorder can affect the hands, causing the fingers to curl into the palm or extend outward without control.
It can affect people of all ages, including children, but symptoms most commonly begin between the ages of 40 and 60 years.
In this article, we look at the different types, symptoms, and possible causes of focal dystonia, as well as how to treat this condition.
Focal dystonia can occur in a range of areas on the body. It causes cramps and involuntary movement.
Dystonia refers to a range of symptoms that affect movement. There are many different types of dystonia, which affect various muscles in the body. Focal dystonia describes any dystonia that remains in one area.
It is the type of dystonia that most commonly develops in adulthood.
There are also different types of focal dystonia, according to the area of the body that it affects. For example:
- Focal hand dystonia: This type of focal dystonia affects the hand, often causing cramps, tremor, or involuntary movement during highly practiced or repetitive hand motions. Writing or playing a musical instrument can cause this condition, leading some people to dub it "writer's cramp" or "musician's cramp." Doctors might refer to it as task-specific dystonia.
- Foot dystonia: Faulty signals from the brain can cause muscles to contract in the foot.
- Tardive dystonia: This type of dystonia occurs as a side effect of taking medications to treat other conditions.
- Paroxysmal dystonia: A rare type of dystonia, which occurs in short attacks and does not cause noticeable symptoms outside of these episodes.
- Voice and laryngeal dystonia: This condition affects the vocal cords, causing spasms that the individual cannot control. These spasms can alter the sound of the voice.
- Neck or cervical dystonia: This term refers to muscle contractions in the neck, which can cause pain and lead to uncomfortable postures, with the head pulling forward, backward, or to one side.
- Blepharospasm: The effects of dystonia can occur around the eye, where they can result in the involuntarily closing of the eyelids.
Many more types of focal dystonia can occur. Doctors categorize them by cause, the age of onset, and the area in which the dystonia has developed.
Symptoms vary according to the type of focal dystonia.
The early symptoms may include a loss of precision in muscle coordination.
For example, the individual may first notice increasing difficulty in using a pen. They may also regularly experience small injuries to the hand and might become more likely to drop items.
The repetitive use of a muscle may lead to trembling and cramping pains.
Significant muscle pain and cramping may result from minor physical activities, such as holding a book and turning its pages.
As well as these specific symptoms, people may experience secondary effects on their continuous muscle and brain activity, including:
- disturbed sleep patterns
- mood swings
- mental stress
- difficulty concentrating
- blurred vision
- digestive problems
- short temper
People with dystonia may also experience depression. As the condition worsens, they may find it difficult to carry out their daily activities.
Some people have symptoms that get worse and then stabilize for years. In other cases, symptoms may stop progressing entirely.
Treatment and lifestyle changes can help slow the progression of focal dystonia. However, if the individual continues to use their muscles in the same way as before, the symptoms might progress more rapidly.
Musicians have a high risk of focal dystonia.
The disorder is sometimes hereditary, but there are other possible causes.
Neurotransmitters are chemicals in the brain that relay information. A shortage of these chemicals or a malfunction in their production in the basal ganglia can lead to dystonia.
The basal ganglia are a collection of brain cells at the front of the brain. They are responsible for sending messages from the brain to various muscles to enable movement.
Secondary dystonia might be the result of another neurological condition, or it may have an environmental cause. An injury during childbirth that results in oxygen deprivation or neonatal brain hemorrhage can lead to dystonia.
Trauma or stroke later in life can have a similar effect.
Some infections and exposure to certain substances can trigger focal dystonia. These substances include some medications, such as dopamine-blocking drugs, heavy metals, and carbon monoxide.
People who perform high-precision hand movements, such as musicians, engineers, architects, and artists, are statistically more likely to develop the disorder.
It also tends to be "task specific," which means that it only poses a problem during certain activities.
Other risk factors include anxiety, which many athletes and musicians experience during stressful competitions and performances.
An individual who already has a neurological condition, such as Parkinson's, Huntington's, or Wilson's disease, may also develop secondary focal dystonia.
Parkinson's occurs due to a lack of dopamine, a "feel-good" neurotransmitter, while Huntington's is an inherited condition in which the person does not have enough cholesterol in their brain. Wilson's disease is a genetic condition that causes copper to build up in the tissues of the body.
The underlying cause will dictate the suitable treatment options. A doctor will, therefore, start by identifying whether a particular presentation of dystonia is primary or secondary.
Electromyography (EMG) is a procedure that uses electrical sensors to help provide a definitive diagnosis. The doctor inserts the sensors into the relevant muscle groups.
These show pulsating nerve signals transmitting to the muscles even when the muscles are at rest.
When performing an intentional activity, muscles in areas that focal dystonia affects will tire very quickly, and some parts of the muscle group will not respond, causing weakness. Other parts of the muscle group may respond excessively or become rigid.
This test can diagnose more severe focal dystonia, but it can be painful.
Anti-seizure and anticholergenic medication can help relieve the symptoms of focal dystonia.
Lifestyle changes may be necessary to reduce the types of movement likely to trigger or worsen dystonic symptoms.
Reducing stress, getting plenty of rest, and engaging in moderate exercise might also help. Relaxation techniques, such as meditation, yoga, and tai chi, might contribute to symptom relief too.
Botox: Botox injections cannot cure dystonia, but they can help relieve symptoms. Botox is a commercially prepared form of botulinum toxin, which the doctor injects directly into the affected muscles.
This protein prevents the neurotransmitters responsible for muscle spasms from reaching the affected muscles. The effects usually last for 3 months, at which point another injection will be necessary.
Clonazepam: A doctor will sometimes prescribe this anti-seizure medicine. However, it has a limited effect, and adverse reactions include mental confusion, sedation, mood swings, and short-term memory loss.
Anticholinergics: This class of medication is effective in treating some types of focal dystonia in some people. The drugs work by blocking the release of a neurotransmitter called acetylcholine. Acetylcholine has links to muscle spasms in some people with dystonia.
Some people have suggested that cannabidiol (CBD), one of the nonpsychoactive cannabinoids present in Cannabis sativa, has the potential to relieve the symptoms of dystonia.
However, research into its effects is still ongoing. Further studies are necessary to qualify CBD as an appropriate remedy for movement disorders, especially considering the risk of cannabis use disorder.
Treating an underlying condition, such as Parkinson's, may help lessen symptoms in people with secondary focal dystonia.
Dystonia is a lifelong disorder, and very few people experience remission or an improvement in symptoms. Life expectancy is normal, but symptoms persist.
Ongoing symptoms may require people with the disorder to limit certain activities.
As individuals learn to live with dystonia, healthcare professionals can help them manage the symptoms by using pain relief and adapting their posture and movements.
How do I know the difference between focal dystonia and a cramp?
Although there is no known cause for focal or task-specific dystonia, you are at higher risk if you are male and have a family history of the disorder.
Recent research indicates that possible risk factors include perfectionism, anxious personality traits, and certain anatomical factors, such as hand size and joint mobility. Hand dystonia often affects musicians, particularly if the onset of musical training occurred at an older age.
As dystonia causes muscle cramps, there is no way to determine if this symptom relates to dystonia or is just a muscle cramp. However, the symptoms of focal dystonia tend to persist, while a cramp is often short-lived.Deborah Weatherspoon, PhD, RN, CRNA Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.