Unknown: Tourette Syndrome
Unknown: Tourette Syndrome
Tourette syndrome (TS) is a disorder of the nervous system characterized by tics, which are involuntary repetitive movements or sounds. It is named for a French neurologist, Georges Gilles de la Tourette (1859–1904), who first described it in a group of nine patients in 1885.
Tourette syndrome is a disorder of the nervous system known for the motor and vocal tics of patients diagnosed with the syndrome. It can affect adults as well as children, but is most commonly diagnosed in children around age seven or slightly older. In most cases TS improves as the child matures and disappears completely by adulthood. Tourette syndrome is considered a spectrum disorder because the symptoms vary in severity from patient to patient; in fact, some doctors think that the diagnosis of Tourette syndrome is often missed because the patient's symptoms are very mild and not noticed by other people. For example, parents often attribute such tics as eye blinking or sniffing noises to vision problems, colds, or allergies.
The tics that characterize TS are sudden, rapid, repeated movements or voice sounds that the person cannot control. The most common first tic in children is a facial tic like eye blinking or grimacing. Motor (movement) tics usually occur before vocal tics, and usually affect the face and neck before moving downward to the arms, chest, or legs. Other common tics include throat clearing, grunting, barking, sniffing, tongue clicking, arm thrusting, shoulder shrugging, jumping, twirling, or kicking. Contrary to popular depictions of TS in the media, the repetition of dirty words, ethnic insults, or curses—known as coprolalia—occurs in only a small minority (about 15 percent) of patients with TS.
The tics may increase or decrease in both number and severity, often disappearing for weeks and months and returning when the person is under stress. Although tics are involuntary, some patients are able to suppress them or manage them for brief periods of time. These patients often feel tension building up when they try to control their tics, however, and will often say that they feel they must release the tension at some point and express the tic. Tics do not go away completely when the patient is sleeping but are usually much less noticeable during sleep.
At one time TS was thought to be a rare condition but is now diagnosed in 1–2 percent of children and adults in the United States. According to the National Institute of Neurological Disorders and Stroke (NINDS), about 200,000 Americans have the most severe form of TS. Some doctors think that as many as 10 percent of Americans may have mild TS.
Babies born prematurely appear to be at increased risk of developing Tourette syndrome in childhood, although the reasons for the connection are not yet clear.
TS appears to be equally common in all racial and ethnic groups; however, boys are four to ten times more likely to develop TS than are girls. The reasons for the gender difference are not known.
The cause of Tourette syndrome is not known. At one time, the disorder was thought to be a psychiatric illness, but most researchers now believe that TS results from a combination of genetic factors and differences in brain functioning. It is known that the disorder runs in families; however, no specific genes associated with the syndrome have been identified. Brain imaging studies suggest that children with TS have brains that are unusually sensitive to a neurotransmitter (brain chemical) called dopa-mine, and that the chemical activates parts of the brain that are responsible for the movements involved in tics. One finding that supports this theory is that medications that block the brain's uptake of dopamine are helpful in controlling tics.
Tourette syndrome often coexists with other neurological disorders like attention-deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). About 40 percent of children diagnosed with TS have only TS; the remaining 60 percent have either TS plus ADHD, or TS plus OCD. A few children with Tourette syndrome also suffer from disorders of impulse control, which may include aggressiveness, sexual acting out, or rage attacks.
The tics characteristic of TS are sometimes categorized as simple or complex tics as well as motor or vocal tics. A simple tic is sudden, brief, and involves only a few muscles. A complex tic is a pattern of movement that involves several groups of muscles and takes slightly longer to perform than a simple tic. Examples of simple tics would be eye blinking (motor) or barking (vocal); examples of complex tics would be flapping the arms (motor) and repeating someone else's words (vocal).
There are no laboratory or imaging tests that can be used to diagnose Tourette syndrome, although the patient's doctor may order an ECG or a blood test to rule out seizure disorders or thyroid problems. The doctor will base the diagnosis of Tourette syndrome on a combination of the patient's symptom history, a history of other family members with TS, and the patient's age. The diagnostic criteria used by the American Psychiatric Association specify that the patient must:
- Have several motor tics and at least one vocal tic for a period of a year, with no more than three consecutive months without a tic.
- Have been under eighteen years of age when the tics started.
- Not be abusing alcohol or drugs, or have any other disease or disorder that could be causing the tics.
It is not unusual for people with mild TS to go undiagnosed for years, read about the syndrome and recognize that they have tics, and visit their doctor to have the diagnosis confirmed.
Mild TS may not need any treatment. Although there are medications that can be prescribed to control severe tics, most doctors prefer to wait for a few months rather than prescribe medications right away. One reason is that the drugs given to control tics all have side effects, particularly weight gain, drowsiness, and difficulty concentrating in school. Another reason is that many children with TS have periods when the tics are less severe.
Many doctors recommend psychotherapy for children with TS to help them cope with the social embarrassment and difficulties with schoolwork that they may be facing. Although TS does not cause depression or learning problems, children may become depressed because of rejection by classmates due to the tics, or they may have trouble learning their lessons in school because their attention is focused on controlling the tics.
Tourette syndrome is not usually a disabling condition, although it can cause social embarrassment to affected children and teenagers. TS is often most severe in the patient's early teens, with symptoms improving in the later teens and improvement continuing into adult life. About a third of adults find that their tics eventually go away; about 10 percent, however, do not experience significant improvement in their thirties or even in their forties.
People with Tourette syndrome have a normal life expectancy. The disorder does not affect a person's basic intelligence or prevent them from completing their education once they are diagnosed; in fact, many people with Tourette syndrome have above-average intelligence. One follow-up study of thirty-one adults with TS found that all the patients finished high school; 52 percent finished at least two years of college, and 71 percent were employed full time or were pursuing advanced degrees. The chief problem confronting people with TS in adult life is an
increased risk of depression, mood swings, and panic attacks compared to the general population.
There is no known way to prevent Tourette syndrome because its causes are not yet fully understood.
A newer form of treatment for TS that is considered experimental as of 2008 is deep brain stimulation or DBS. In DBS, a battery-operated device is implanted in the brain to deliver carefully targeted electrical stimulation to the parts of the brain that control movement. In addition to clinical trials of DBS and some newer drugs as treatments for Tourette syndrome, other researchers are using advanced imaging techniques to study the parts of the brain involved in tics. Still other scientists are looking for specific genes that may be linked to TS.
SEE ALSO Attention-deficit hyperactivity disorder; Obsessive-compulsive disorder; Prematurity
WORDS TO KNOW
Coprolalia: The medical term for uncontrollable cursing or use of dirty words.
Involuntary: Not under the control of the will.
Neurotransmitters: Chemicals produced by the body that transmit nerve impulses across the gaps between nerve cells.
Tic: A sudden repetitive movement or utterance. Tourette syndrome is considered a tic disorder.
Chowdhury, Uttom, and Mary Robertson. Why Do You Do That?: A Book about Tourette Syndrome for Children and Young People. Philadelphia: Jessica Kingsley Publishers, 2006.
Haerle, Tracy, ed. Children with Tourette Syndrome: A Parents' Guide. Bethesda, MD: Woodbine House, 2007.
Shimberg, Elaine Fantle. Tourette Syndrome: What Families Should Know. Yarmouth, ME: Abernathy House Publishing, 2008.
Mayo Clinic. Tourette Syndrome. Available online at http://www.mayoclinic.com/health/tourette-syndrome/DS00541 (accessed June 29, 2008).
National Institute of Neurological Disorders and Stroke (NINDS). Tourette Syndrome Fact Sheet. Available online at http://www.ninds.nih.gov/disorders/tourette/detail_tourette.htm (accessed June 29, 2008).
Tourette Syndrome Association. Facts about Tourette Syndrome. Available online in PDF format at http://tsa-usa.org/People/LivingWithTS/Images/Fact_Sheet.pdf (accessed June 29, 2008).
Tourette Syndrome Association video clip. “I Have Tourette's, But Tourette's Doesn't Have Me”. Available online at http://www.tsa-usa.org/news/HBO_Release_apr06_update.htm (accessed June 29, 2008).