Table 1.

Diagnostic criteria for specific types of parkinsonism

* This group included other rare disorders (e.g., cortical-basal ganglionic degeneration) that were not represented in our population.
† Details about progressive supranuclear palsy and multiple system atrophy were reported elsewhere.13
Parkinsonism: A syndrome with any two of
1. Resting tremor
2. Bradykinesia
3. Rigidity
4. Impaired postural reflexes
Parkinson’s disease: Parkinsonism with all three of
1. No secondary cause (e.g., repeated stroke with stepwise progression; repeated head injury; history of encephalitis; neuroleptic treatment within 6 months before onset; hydrocephalus; brain tumor)
2. No documentation of levodopa unresponsiveness at doses of at least 1 g/d (if applicable)
3. No prominent or early (within 1 year of onset) signs of more extensive nervous system involvement not explained otherwise (e.g., dementia or dysautonomia)
Drug-induced parkinsonism: Parkinsonism with all three of
1. Symptom onset while on neuroleptic or dopamine-depleting drug treatment
2. No symptoms before drug treatment
3. Resolution of symptoms within 6 months of withdrawal of drug treatment, if applicable
Parkinsonism in dementia: Parkinsonism with evidence of dementia before or within the first year of parkinsonian symptoms
Parkinsonism unspecified: Parkinsonism with insufficient clinical documentation or not meeting any of the other criteria
Other parkinsonism*
Vascular parkinsonism: Parkinsonism with all three of
1. Abrupt onset
2. Nonprogressive or stepwise course
3. Infarct(s) in appropriate basal ganglia on CT or MRI
Progressive supranuclear palsy: Criteria by Collins et al.11
Multiple system atrophy: Criteria by the Consensus Committee of the American Autonomic Society and the American Academy of Neurology, 1996 (modified)12