Unfortunately, there is no definitive test to diagnose Parkinson's. The NICE clinical guideline recommends that people with suspected Parkinson's should be seen within six weeks, or two weeks if a later stage of the disease is suspected. It's important that treatment does not begin until a specialist sees the patient and the diagnosis is confirmed.

The diagnostic process differs from patient to patient. A consultant will take a full history of the patient and conduct a neurological examination, as well as check routine bloods for any deficiency and to rule out a condition known as Wilson's disease as the cause of any presenting symptoms. MRI and CT scans can be used to rule out other causes if necessary.

When a person displays the symptoms of Parkinson's but doesn't have a formal diagnosis, the symptoms are called 'parkinsonism'. These symptoms can result from treatment with particular medicines, such as dopamine antagonists and atypical antipsychotics, or other conditions, such as stroke or brain injury and rare disorders, such as Wilson's disease or multiple system atrophy.