Parkinson’s disease is difficult to diagnose as there are no specific tests to confirm the disease, and the clinician, usually a neurologist, relies on multiple ways to assess its nature and progression. Parkinson’s symptoms also overlap with those of other neurodegenerative diseases, which makes the diagnosis even more complicated.

The presence of at least two of the four symptoms listed below indicates a strong case for Parkinson’s:

neurologist might ask the patient to write, draw, walk, or speak, and test their sense of smell. Loss of smell (hyposmia) — along with signs of depression, anxiety, and constipation  — may be one of the indicators for the onset of Parkinson’s. 

There are several tests, listed below, that can help diagnosis Parkinson’s disease.

Imaging tests

Imaging tests can help a neurologist find out whether there is any malfunction in the working of the brain and nervous system. Some of these tests include computerized tomography (CT), magnetic resonance imaging (MRI), DaTscan, and positron emission tomography (PET). DaTscan and PET can help to identify the loss of dopamine-producing nerve cells, a hallmark of Parkinson’s disease, while CT and MRI help to rule out irregularities in other parts of the brain.

Levodopa test

Levodopa is a molecule from which dopamine is synthesized in the brain. It can be used as treatment in all stages of Parkinson’s and also to aid in diagnosis. A neurologist recommends a sufficient dose of levodopa to see whether it has any effect on a patient’s symptoms. If symptoms improve after the administration of levodopa, a diagnosis of Parkinson’s disease is confirmed in the patient.


Real-time quaking-induced conversion (RT-QuIC) is a relatively new test that has been developed by the National Institutes of Health for early diagnosis of neurodegenerative diseases such as Parkinson’s. This test detects damaged forms of the protein alpha-synuclein, which is usually implicated in such diseases.


Parkinson’s News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.