Pediatricians, allergists and ophthalmologists are among the first to see or identify a child as having tics, although the majority of tics are first identified by the childs parents. Coughing, blinking, and tics that mimic unrelated conditions such as asthma are commonly misdiagnosed. In the UK, there is an average delay of three years between symptom onset and diagnosis. Differential diagnosis
Tics that may appear to mimic those of Tourettes—but are associated with disorders other than Tourettes—are known as tourettism and are ruled out in the differential diagnosis for Tourette syndrome. The abnormal movements associated with choreas, dystonias, myoclonus, and dyskinesias are distinct from the tics of Tourettes in that they are more rhythmic, not suppressible, and not preceded by an unwanted urge. Developmental and autism spectrum disorders may manifest tics, other stereotyped movements, and stereotypic movement disorder. The stereotyped movements associated with autism typically have an earlier age of onset; are more symmetrical, rhythmical and bilateral; and involve the extremities (for example, flapping the hands).If another condition might better explain the tics, tests may be done; for example, if there is diagnostic confusion between tics and seizure activity, an EEG may be ordered. An MRI can rule out brain abnormalities, but such brain imaging studies are not usually warranted. Measuring thyroid-stimulating hormone blood levels can rule out hypothyroidism, which can be a cause of tics. If there is a family history of liver disease, serum copper and ceruloplasmin levels can rule out Wilsons disease. The typical age of onset of TS is before adolescence.
Children may be less aware of it than are adults, but their awareness tends to increase with maturity; by the age of ten, most children recognize the premonitory urge.Premonitory urges which precede the tic make suppression of the impending tic possible. Because of the urges that precede them, tics are described as semi-voluntary or "unvoluntary", rather than specifically involuntary; they may be experienced as a voluntary, suppressible response to the unwanted premonitory urge. The ability to suppress tics varies among individuals, and may be more developed in adults than children. People with tics are sometimes able to suppress them for limited periods of time, but doing so often results in tension or mental exhaustion. People with Tourettes may seek a secluded spot to release the suppressed urge, or there may be a marked increase in tics after a period of suppression at school or work. Children may suppress tics while in the doctors office, so they may need to be observed when not aware of being watched.Complex tics related to speech include coprolalia, echolalia and palilalia. Coprolalia is the spontaneous utterance of socially objectionable or taboo words or phrases. Although it is the most publicized symptom of Tourettes, only about 10% of people with Tourettes exhibit it, and it is not required for a diagnosis. Echolalia (repeating the words of others) and palilalia (repeating ones own words) occur in a minority of cases.