Parkinson’s disease, a progressive disease of the central nervous system, is characterized by tremors, muscle stiffness, slowness of movement (bradykinesia), and poor posture and balance. It is currently diagnosed based on symptoms already evident.

Patients have lower than usual levels of dopamine in the brain, a chemical messenger involved in muscle movement and coordination.

There are no specific tests to diagnose Parkinson’s disease, making a proper diagnosis particularly difficult in early disease stages.

Medical history and physical examination

The diagnosis is usually based on the person’s medical history and a physical examination that focuses on four common disease features: shaking or tremor, bradykinesia or slow movements, rigidity in the limbs or truck, and postural instability that makes walking and balance difficult (and causes falls).

Imaging tests, such as MRI, PET or DAT scans, may be performed to rule out other conditions that may cause symptoms similar to Parkinson’s, and blood tests taken for this same reason.

Levodopa test

The doctor may ask the patient to take levodopa, a medication that temporally restores dopamine levels in the brain and is used to treat Parkinson’s. If the patient’s symptoms improve, the disease is likely.

Scientists are working to find disease biomarkers that would help to accurately diagnose Parkinson’s at earlier stages.


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.