Diagnosis of Parkinson’s disease is a clinical one, based on history and physical examination. There are no lab tests to definitively diagnose the condition. Your doctor will ask about your medical history and perform a thorough physical exam. A systematic neurological exam will include testing your reflexes and observing things like muscle strength throughout your body, coordination, balance, and other details of movement, including:

  • Muscle tone
  • Rapid alternating movements
  • Gait, posture
  • Postural stability
  • Quickness and precision of movement
  • Observation of a tremor (during rest or activity)

A mini mental status exam will be performed; questions pertaining to mood, thoughts, and behavior will be asked. Activities of daily living will be evaluated, such as dressing, cutting and eating food, swallowing, hygiene, walking, and falls.

If you have at least two of the most characteristic symptoms of Parkinson’s disease, then your doctor will probably be able to diagnose you with the disorder. The three symptoms that are considered “hallmarks” of Parkinson’s disease include:

  • Tremor while at rest
  • Rigidity
  • Slowness of movement (bradykinesia)

Other symptoms of Parkinson’s disease include:

  • Blank facial expression
  • Decreased eye blinking
  • Stooped posture
  • Depression
  • Sleep disturbances
  • Shuffling gait
  • Difficulty with initiating movement
  • Difficulty rising from a sitting position
  • Loss of postural stability
  • Difficulties with activities with daily living
  • Voice changes
  • Swallowing and drooling difficulties
  • Changes in handwriting
  • Loss of smell

If your doctor has questions about the cause of your symptoms, you may be given tests to try to exclude the possibility of other disorders. These tests may include blood tests, urine tests, CT scans , or MRI scans . Although none of these tests can actually diagnose Parkinson’s disease, they may reveal the presence of some other condition that could be responsible for your symptoms.

PET Scan

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There are some relatively expensive brain imaging tests that can be used to help evaluate for Parkinson’s disease. These are not always covered by insurance and are only available at specialized centers. They also must be viewed in the context of your clinical symptoms and findings. These tests include:

  • PET scan—You’ll be given an injection of a substance that will make the pictures of your brain clearer. You’ll lie on a table, which will slowly move you through a ring-shaped scanner. This test may take about 30 minutes or longer.
  • Single photon emission computed tomography (SPECT scan)—You’ll be given an injection of a substance that will make the pictures of your brain clearer. You’ll lie on a table, and a camera-like object will slowly rotate around you. This test may take about 90 minutes or longer.

If your doctor is not certain of the diagnosis, she may give you a trial of the medication levodopa, which is often used to treat Parkinson’s disease. If your symptoms improve, it supports the diagnosis of Parkinson’s disease.