Tourette's syndrome - Diagnosis 

The first stage in confirming a diagnosis of Tourette’s syndrome is to rule out other possible causes of your child’s symptoms.

These include:

• allergies, if they are sniffing and coughing
• vision problems, if they are blinking more than usual

It is also necessary to rule out other conditions that can cause tic-like behaviours, such as

• autistic spectrum disorder – a developmental disorder that causes problems with social interaction, learning and behaviour
• dystonia – a condition that causes involuntary muscle spasms
• Huntington's disease – a genetic condition that can cause a range of symptoms including muscle twitching

To rule these out, your child may be referred to a number of experts, such as a:

• neurologist – a doctor who specialises in treating conditions that affect the brain and nervous system
• psychiatrist – a doctor who specialises in treating mental health conditions
• educational psychologist - a health professional who works with children who have learning, developmental or behavioural difficulties

To rule out other possible causes of your symptoms, your child might be referred for tests, such as eye tests or a skin prick test. A skin prick test is used to see if your child has an allergy. Small amounts of potentially allergic-causing substances, such as pollen, are placed onto the skin to see if there is a reaction.

Brain-imaging scans can also be used to check if there are any abnormalities with the brain and nervous system that could suggest a neurological cause of your child’s symptoms other than Tourette’s syndrome. Scans that can be used include:

• computerised tomography (CT) scan –  where a series of X-Rays are taken to build up a detailed 3D image of the brain
• magnetic resonance imaging (MRI) scan – where strong fluctuating magnetic fields are used to produce a detailed image of the inside of the brain

Confirming the diagnosis

At present, there is no one test that can be used to diagnose Tourette’s syndrome.

A diagnosis can only be made by assessing your child’s symptoms to see if they follow the usual pattern that is associated with the condition.

A confident diagnosis of Tourette’s syndrome can usually be made if:

• Your child’s symptoms are not being caused by other medical conditions, or any medication that you are taking.
• Your child started experiencing tics before the age of 18.
• Your child has had several physical tics and at least one phonic tic.
• Your child’s tics occur many times during the day, nearly every day.
• Your child has been having tics for at least a year.