It is essential that multiple motor tics (twitches) and one or more vocal tics (noises) are present for at least one year for a definitive diagnosis of Tourette syndrome. These tics may appear simultaneously or at different times and will tend to fluctuate in occurrence and intensity. The onset of symptoms is usually before the age of twenty-one with the average age of onset being seven. Tourette syndrome is biochemically based and genetically transmitted. Motor and vocal tics may be simple or complex.

Simple motor tics include tics of the head and face such as eye blinking, squinting, eye rolling, nose twitches, mouth twitches, making faces, tongue protrusion, nodding or tilting of the head sideways, shoulder shrugging, arm jerking and extending, leg kicking and knee jerks, and abdominal contractions such as pulling in the tummy. Complex motor tics include the smelling and licking of objects, spitting, touching parts of one’s own body and touching others, and unusual gaits such as twirling, squatting, hopping, skipping and bending down.

Simple vocal tics include sounds such as repetitive sniffing, snorting, throat clearing, coughing and gulping, while more complex vocal tics include grunting, barking, yelping, quacking, whistling and belching.

Other characteristic features of the syndrome can include palipraxia (repetitive movements such as knotting a tie over and over again), echopraxia (copying or imitating what other people do), echolalia (repeating or imitating what people say), palilalia (repeating oneself over and over, or constantly repeating the last word or phrase uttered by oneself) and copraxia (involuntary inappropriate cursing and swearing).

Most students with Tourette syndrome test within average limits on standardised IQ (Intelligence Quotient) tests. The difficulties experienced by students with Tourette syndrome in the classroom are often related to the symptoms of the disorder themselves (such as when tics disrupt other classmates or interfere with handwriting or participation in class discussions). Some difficulties are caused by co-existing symptoms such as obsessive compulsive behaviour and attention deficit hyperactivity disorder (ADHD), while others are associated with learning and academic learning difficulties. Tics such as severe head shaking, neck stretching or eye rolling may cause the student to be unable to look directly at the teacher or read easily. Hand tics often interfere with legibility of handwriting and visual spatial deficits may result in the student having difficulty with copying from the board or elsewhere. Tics may also impede activities that have strict timing criteria, which may result in lowered test scores and associated inaccurate estimates of ability.