Clinical features of Parkinson's disease:
(1) resting tremor
(2) rigidity
(3) asymmetric onset
(4) bradykinesia
Features suggesting an alternative diagnosis:
(1) dementia preceding motor symptoms
(2) dementia in first year after symptom onset
(3) prominent postural instability in the first 3 years after symptom onset
(4) freezing phenomenon in the first 3 years after symptom onset
(5) supranuclear gaze palsy (other than restriction of upward gaze)
(6) slowing of vertical saccades (rapid small movements in both eyes that occur when changing the point of fixation)
(7) severe, symptomatic dysautonomia unrelated to medications
(8) presence of located focal brain lesion that can produce parkinsonian symptoms
(9) drug capable of causing Parkinson's disease taken within the past 6 months
Criteria for definite Parkinson's disease - both of the following:
(1) meets criteria for possible Parkinson's disease (below)
(2) histologic evidence of Parkinson's disease found on brain examination at autopsy
Criteria for probable Parkinson's disease - all 3 of the following:
(1) 3 or all 4 of the clinical features of Parkinson's disease
(2) no features present indicating an alternative diagnosis (items #3 and #4 require symptoms for at least 3 years)
(3) substantial and sustained response to levodopa or dopamine agonist
Criteria for possible Parkinson's disease - all 3 of the following:
(1) 2 or more of the 4 clinical features of Parkinson's disease
(2) either no features for an alternative diagnosis are present after 3 years OR none of the features are present to date if disease duration is less than 3 years
(3) either the patient has a substantial and sustained response to levodopa or a dopamine agonist OR the patient has not had an adequate clinical trial (viz, NOT adequate clinical trial of medication with no or inadequate or nonsustained response).
