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Parkinson's Disease Tests

We look at the diagnosis of Parkinson's disease as a three-step process.


Step 1: Identify the presence of parkinsonism.
Parkinsonism is a clinical syndrome defined by the presence of the following symptoms:

  • Bradykinesia (slowness of movement)
  • Rigidity or Stiffness of the limbs
  • Postural Instability (stooped, slumped posture) or loss of balance
  • Resting Tremor (especially a pattern called pill rolling)
  • Tremor due to the tremor's resemblance to this action)

The presence of two of these five cardinal features of the syndrome is required to make the diagnosis of parkinsonism.


Step 2: Identify the cause of parkinsonism.
Parkinson's disease is responsible for 75% of all cases of parkinsonism.
Other causes include:

  • Medications: long term use of certain drugs can induce symptoms similar to Parkinson's disease
  • Infections: certain viral infections that cause the brain to swell and result in Parkinson's-like symptoms
  • Structural or vascular lesions: tumor, stroke, hydrocephalus
  • Other degenerative disorders: Progressive Supranuclear Palsy (PSP), Multiple System Atrophy (MSA)

Step 3: Prove that the diagnosis is accurate and correct.
Parkinson's Disease can be difficult to diagnose and the best ways to tell if the diagnosis is correct are:

  • Positive response to treatment with levodopa (Sinemat®)
  • No response or short-lived response to treatment: parkinsonism caused by other degenerative conditions usually does not respond to treatment.
  • PET scan to confirm or rule out the diagnosis of Parkinson's.

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