Section 6. Brain, Spinal Cord, and Nerve Disorders

Chapter 91. Movement Disorders

Topics: Introduction | Myoclonus | Tremor | Parkinson's Disease | Progressive Supranuclear Palsy | Shy-Drager Syndrome | Tics | Chorea and Athetosis | Huntington's Disease | Dystonia | Coordination Disorders

Tics

Tics are brief, rapid, purposeless, simple or complex involuntary movements that are virtually identical to one another and are repetitive but not rhythmic.

Simple tics, such as excessive blinking, may begin as nervous mannerisms, often during childhood, and may disappear without any treatment. Complex tics, such as those that occur in Tourette's syndrome, often resemble fragments of normal behavior.

Tourette's Syndrome

Tourette's syndrome is a hereditary disorder in which muscle and vocal tics occur frequently throughout the day for at least one year.

Tourette's syndrome is 3 times more common among men than among women. It often begins in early childhood. The cause is unknown but is thought to be an abnormality in dopamine or another brain neurotransmitter (a chemical messenger that nerve cells use to communicate).

Symptoms and Diagnosis

Tourette's syndrome often begins with muscle tics. Many people who do not have this disorder have simple tics, such as repetitive eye blinks, which are nervous habits and may disappear with time. However, the tics in Tourette's syndrome consist of more than just a blink. For example, people with this disorder may repeatedly move the head from side to side, blink the eyes, open the mouth, and stretch the neck. Before a tic occurs, the person may feel an urge to perform the movements of the tic. The tic can sometimes be postponed from seconds to hours but eventually becomes irresistible. Some people can suppress some of the tics, usually with difficulty. However, most people have trouble controlling the tics, especially during times of emotional stress.

The disorder progresses to bursts of complex tics, including vocal tics, hitting, kicking, and sudden, irregular, jerky breathing. Vocal tics may start as grunting, snorting, humming, or barking noises and progress to compulsive, involuntary bouts of cursing. For no apparent reason and often in the midst of conversation, some people with Tourette's syndrome may call out obscenities. Use of words related to feces (coprolalia) is common. These vocal outbursts are sometimes mistakenly thought to be intentional, especially in children. Repetition of words immediately after hearing them (echolalia) is also common.

People with Tourette's syndrome often have difficulty functioning and experience considerable anxiety in social situations. In the past, they were shunned, isolated, or even thought to be possessed by the devil. Many people with the disorder develop impulsive, aggressive, and self-destructive behaviors; about half of the people develop obsessive-compulsive behavior. Children with Tourette's syndrome often have difficulty learning. Whether the disorder itself or the extraordinary stresses of living with the disorder cause these behaviors is unclear.

Diagnosis is based on the symptoms. Early diagnosis can help parents understand that the tics their children have are not voluntary and that punishment cannot stop the tics.

Treatment

For simple tics, benzodiazepines (such as clonazepam and diazepam), which are mild sedatives, may help. Clonidine, a drug used to treat high blood pressure, occasionally helps because it blocks the action of norepinephrine, a neurotransmitter that is thought to contribute to the tics. Clonidine is more useful in controlling anxiety and obsessive-compulsive behavior; however, it may cause excessively low blood pressure.

When the disorder is severe, antipsychotic drugs may be used to help suppress the tics, even though psychosis is not the cause. Haloperidol, the most commonly used antipsychotic drug, is effective but can cause side effects such as repetitive involuntary movements of the mouth and tongue (tardive dyskinesia (see Section 7, Chapter 107)), stiffness, weight gain, blurred vision, sleepiness, and dulled, slowed thinking. Pimozide, fluphenazine, and risperidone--also antipsychotic drugs--can reduce the frequency and intensity of the tics. These drugs may have fewer side effects.

Injecting botulin into the muscles producing the tics may decrease the abnormal movements as well as the urge that precedes them. Botulin, the bacterial toxin that causes botulism, is used to paralyze muscles.