Table 1.

The criteria for Parkinson’s disease (PD) diagnostics according to the Movement Disorder Society guidelines.

Category	Diagnostic Features
Main Parkinsonism Diagnostics Criteria	Bradykinesia (with speed and amplitude decrement) in combination with rest tremor, or/and muscle rigidity.
Supportive Criteria	An adequate response to dopaminergic therapy. Levodopa peak–dose dyskinesia. Limb rest tremor. Hyposmia confirmed by the University of Pennsylvania Smell Identification Test (UPSIT), and/or progression of myocardial sympathetic denervation assessed by metaiodobenzylguanidine (MIBG) myocardial scintigraphy.
Absolute Exclusion Criteria	Cerebellar abnormalities. Downward gaze paresis or slowing of vertical saccades. A behavioral variant of frontotemporal dementia or primary progressive aphasia during the first 5 years of the disease. “Lower body parkinsonism” for more than 3 years. Treatment with neuroleptics during the sufficient period and in a dose that can cause parkinsonism. Absence of observable response to levodopa therapy in high doses. Unequivocal cortical sensory loss (i.e., graphesthesia or stereognosis with intact primary sensory modalities), clear limb ideomotor apraxia, or progressive aphasia. Normal functional neuroimaging of the presynaptic dopaminergic system confirmed by single-photon emission or positron emission tomography. The presence of another disease that can cause Parkinson’s syndrome.
Red Flags	Rapid progression of gait impairment requiring regular use of wheelchair within 5 years of onset. Absence of progression of motor symptoms or signs over 5 or more years unless related to treatment. Early bulbar dysfunction: severe dysphonia or dysarthria or severe dysphagia within first 5 years. Inspiratory respiratory dysfunction: either diurnal or nocturnal inspiratory stridor or frequent inspiratory sighs. Severe autonomic failure in the first 5 years of the disease. E.g., (a) severe orthostatic decrease of blood pressure within 3 min of standing by at least 30 mm Hg systolic or 15 mm Hg diastolic or (b) severe urinary retention or urinary incontinence in the first 5 years of the disease. Recurrent (> 1/year) falls because of impaired balance within 3 years of disease. Disproportionate anterocollis (dystonic) or contractures of hand or feet within the first 10 years. Absence of any of the common nonmotor features of disease despite 5 years of the disease duration including sleep disorders, autonomic dysfunction, hyposmia, neuropsychiatric disorders (depression, anxiety, or hallucinations). Otherwise-unexplained pyramidal tract signs, defined as pyramidal weakness or clear pathologic hyperreflexia. Bilateral symmetric parkinsonism. The patient or caregiver reports bilateral symptom onset with no side predominance and no side predominance is observed on objective examination.