How is Tourette's syndrome diagnosed?
Diagnosis of Tourette's syndrome is based on the patient's medical history and the presence of tics. Diagnosis often requires keeping records of the child's symptoms and school performance over a period of time. Tourette syndrome is diagnosed by observing the symptoms and asking whether relatives have had a similar condition. To qualify as Tourette syndrome, both motor and vocal tics should be present for at least a year and should begin before age 18 (or, some believe, age 21). There are no specific tests for Tourette syndrome.
Often, the diagnosis is delayed because the patient is misunderstood not only at home and at school, but often in the doctor's office as well. It may take some time for the patient to trust the doctor enough not to suppress the strangest or most alarming tics. Blood tests may be done in some cases to rule our other movement disorders. A test of the brain's electrical activity (electroencephalograph or EEG) is often abnormal, but not specific. Medication history is very important in making the diagnosis as well, because stimulant drugs my provoke tics or aggravate the symptoms of Tourette syndrome.
Although some children are bothered little by tics, other children are greatly affected. To evaluate the effect tics have on a child's life, the doctor will often ask parents questions about areas of the child's life. The child may also need psychological testing and testing for learning problems. It can be difficult to diagnose Tourette's syndrome because tics (or symptoms that look like tics) can be caused by other related disorders. Tests that may be done to check for other conditions include an electroencephalogram (EEG) or computed tomography (CT) scan of the head to see if a person may have seizures or other brain problems. Blood tests may also be done to check for other conditions, including overuse of certain medications (such as amphetamines) or rare medical conditions, such as not being able to break down copper in the body (Wilson's disease).