How is Tourette's syndrome (TS) diagnosed?
There are currently no X-rays or lab tests that can be performed to confirm a TS diagnosis. The clinical diagnosis of TS is based on a combination of factors, including:
- Careful and detailed medical and family history.
- Complete physical and neurological exam (the results of these exams are usually normal but may sometimes be needed to rule out other illnesses).
- Onset of involuntary movements (tics) between the ages of 3 and 21.
- Presence of recurrent, multiple motor and vocal tics, but not necessarily occurring at the same time.
- Tics that occur many times a day, nearly every day or on and off throughout the duration of a year or longer.
- Changing severity of tics and change in the number, frequency, type and location of tics.
- Duration of symptoms for more than one year.
Differentiating tics from other types of uncontrollable movements (such as myoclonus, chorea, athetosis, and dystonia) can be done by history and by observation of the involuntary movements.
An accurate diagnosis is sometimes difficult in patients who have a relatively recent onset of tics or in those who do not have all of the symptoms of TS as listed previously.
Electroencephalogram (EEG), magnetic resonance imaging (MRI) and computed tomography (CAT scan or X-ray of the brain) tests are not needed to confirm a TS diagnosis but may be performed to rule out other neurological conditions.
Medical researchers are looking for biological "markers" which may be useful in diagnosing patients even before clinical signs are present.