DIAGNOSIS

Currently, there isn't a specific test to diagnose Parkinson's disease. A neurologist, a doctor trained in nervous system conditions, makes the diagnosis based on your medical history, a review of your symptoms, and a neurological and physical exam.

It can take time to diagnose Parkinson's disease. Healthcare professionals may recommend regular follow-up appointments with neurologists trained in movement disorders to evaluate your condition and symptoms over time and diagnose Parkinson's disease.

Your healthcare team may order some of these tests and procedures:

• Physical and neurological exam. This includes taking your medical history and doing a neurological exam that tests your thinking and mental abilities, senses, coordination, and reflexes.
• Blood and lab tests. These are used to rule out other conditions that may be causing your symptoms.
• Imaging tests, such as an MRI, brain ultrasound and PET scan. These are used to rule out other conditions. They are not very helpful in diagnosing Parkinson's disease.
• A specific single-photon emission computerized tomography (SPECT) scan called a dopamine transporter (DAT) scan. This can help support the suspicion that you have Parkinson's disease and help identify different types of tremor. But it is your symptoms and the results of your neurological exam that determine your diagnosis. Most people do not require a DAT scan.
• Genetic testing. This tests for gene changes if there is a known family history of Parkinson's disease or if you have early-onset disease.
• A short, low-dose treatment of medicines. You may be given medicines used to treat Parkinson's disease to see if you get better. If your symptoms show significant improvement, this may help confirm your diagnosis. You must be given a sufficient dose to show the benefit, as getting low doses for a day or two isn't reliable.
• Follow-up appointments. Regular appointments with neurologists trained in movement disorders may be needed over time to confirm a diagnosis.
• Alpha-synuclein test. This test, also called an alpha-synuclein seed amplification assay, detects Parkinson's disease before symptoms begin. Alpha-synuclein clumps are a hallmark sign of Parkinson's disease. Healthcare professionals can test for this condition in the skin or spinal fluid.
  Alpha-synuclein is found in Lewy bodies. It forms clumps that the body can't break down. The clumps spread and damage brain cells.
  In a 2023 study, researchers tested the spinal fluid of more than 1,000 people to look for clumps of the protein alpha-synuclein. The test accurately identified people with Parkinson's disease 87.7% of the time. The test also was highly sensitive for detecting people at risk of Parkinson's disease.
  This study of the alpha-synuclein seed amplification assay was the largest so far. Some researchers say the study may be a breakthrough for Parkinson's disease diagnosis, research and treatment trials. But larger studies are needed.
  There's hope among researchers that in the future, the test could be done using blood samples rather than spinal fluid.