Key clinical findings:
(1) tremor, which may be postural and/or resting
(2) rigidity
(3) bradykinesia
(4) postural reflexes
Findings not used:
(1) progressive course: the progression may be slow and so is not suitable for diagnosis of early disease
(2) response to levodopa or other dopaminergic drug: confusion might occur with progressive supranuclear palsy and multiple system atrophy which may show a limited response
Criteria for definite idiopathic Parkinson's disease - one of the following:
(1) 3 or 4 of the key clinical findings
(2) 2 of the key clinical findings with one of (resting tremor, rigidity, bradykinesia) assymmetrical
Criteria for probable idiopathic Parkinson's disease - one of the following:
(1) 2 of the key clinical findings and not meeting the criteria for definite PD
(2) one of (resting tremor, rigidity, bradykinesia) assymmetrical
Criteria for possible idiopathic Parkinson's disease - one of the following:
(1) postural or resting tremor of recent onset
(2) rigidity
(3) bradykinesia
Exclusions:
(1) exposure to drugs or toxins causing Parkinson's disease
(2) Wilson's disease
(3) Huntington's chorea
(4) acanthocytosis
(5) prominent gaze palsy
(6) cerebellar deficit
(7) autonomic disturbances unrelated to therapy
(8) marked pyramidal signs
(9) severe dyspraxia
(10) heavy iron deposition in the basal ganglia
(11) failure to respond to an adequate dose of levodopa (1,500 mg) with a peripheral decarboxylase inhibitor (exception if unable to tolerate that dose because of side effects)
