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 percent 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.