(See also Overview of Movement Disorders.)
Dystonia can also occur in muscles other than those in the neck.
In cervical dystonia, contraction of the neck muscles causes the neck to turn from its usual position. Cervical dystonia is the most common dystonia.
The neck may move in one or more of the following ways:
One form (called adult-onset cervical dystonia) begins in adulthood. Because it causes the neck to rotate, it is sometimes called spasmodic torticollis (in Latin, "torti" refers to twisted and "collis" refers to neck). It is the most common dystonia that affects only one part of the body. Usually, the cause is unknown, but in some people, spasmodic torticollis is caused by a genetic mutation. Stress and emotional problems may make spasmodic torticollis worse.
Cervical dystonia can
Rarely, an emotional problem is thought to contribute.
Symptoms of cervical dystonia may begin at any age but usually begin between the ages of 20 and 60, most often between ages 30 and 50.
Symptoms usually begin gradually. Rarely, they begin suddenly and progress rapidly.
Sometimes symptoms begin with shaking the head from side to side, as if people are shaking their head to say no. Some neck muscles may contract and stay contracted, or they may contract intermittently, twisting the neck. The contractions may be painful. The head may be turned to one side or pulled forward or backward. Sometimes one of the shoulders is raised.
Symptoms range from mild to severe. Usually, the spasms worsen slowly for 1 to 5 years, then plateau. In about 10 to 20% of people, they disappear on their own, within 5 years from when symptoms begin. Spasms are more likely to disappear when they are mild and begin at a young age. However, they may persist for life, restricting movement and permanently twisting the head, neck, and shoulders in a distorted position.
The diagnosis of cervical dystonia is based on symptoms and a neurologic examination.
Some physical techniques can sometimes temporarily relieve spasms. Physical therapy may help by improving flexibility. Therapists may also help people identify which movements worsen spasms and which ones relieve them. Biofeedback (using relaxation techniques to control unconscious body processes, such as heart rate and muscle tension) or massage may help some people.
People may find certain tricks that may briefly relieve spasms. They include lightly touching the chin, cheek, upper face, or back of the head. These tricks are usually more effective if done on the side opposite the spasm.
When an emotional problem contributes, treatment is best managed by a team of doctors, including a psychiatrist, a psychologist, and a neurologist.
In about 70% of people with cervical dystonia, injections of botulinum toxin into the affected muscles can reduce painful spasms for 1 to 4 months and allow the head to return to a more normal position. However, for continuous relief, injections must be repeated every 3 to 4 months because the benefit of botulinum toxin wears off over time. In a few people who are repeatedly given to botulinum injections, the body produces antibodies that inactivate the toxin. If the affected muscles are tiny or deep in the body, electromyography (stimulating muscles and recording their electrical activity) may be done to identify the muscles to be injected.
Certain drugs, given by mouth, may help, but they control the spasms in only about 25 to 33% of people. These drugs include
Anticholinergic drugs, such as trihexyphenidyl
A benzodiazepine (a sedative), particularly clonazepam
Baclofen (a muscle relaxant)
Carbamazepine (an antiseizure drug)
Anticholinergic drugs are given for their effects, which can lessen spasms. However, these drugs also have other, troublesome side effects (such as confusion, drowsiness, and dry mouth), which may limit their use.
All of these drugs are started in low doses. Doses should be increased until symptoms are controlled or side effects cannot be tolerated. Side effects from these drugs are particularly likely in older people.
The role of surgery for cervical dystonia is controversial. Surgery involves cutting the nerves to the affected muscles, so that nerves can no longer stimulate the muscle to contract. However, after this procedure, the muscles are permanently weakened or may be paralyzed. When the procedure is done by skilled surgeons, benefits outweigh potential complications.
If symptoms are severe and all of the usual treatments have been ineffective, deep brain stimulation can be done. For this procedure, tiny electrodes are surgically implanted in part of the basal ganglia (collections of nerve cells that help initiate and smooth out voluntary muscle movements). The electrodes send small amounts of electricity to the specific area of the basal ganglia that causes cervical dystonia and thus help lessen symptoms.