Core motor features | Core autonomic features |
Parkinsonism - Bradykinesia plus rigidity or tremor
- Poor levodopa responsiveness
| Cerebellar syndrome - Gait ataxia
- Limb ataxia
- Cerebellar dysarthria
- Oculomotor dysfunction (sustained nystagmus or saccadic hypermetria)
| Voiding dysfunction - Unexplained voiding difficulties
- Postvoid residual volume (>100 mL for c.e.)
- Secondary causes excluded (eg, bladder outflow obstruction due to prostate enlargement)
| Urinary urge incontinence - Involuntary urine leakage associated with urgency
- Non-neurogenic causes excluded (eg, prior pelvic surgery, pelvic floor prolapse)
| Neurogenic orthostatic hypotension - ≥20 mmHg systolic blood pressure drop within 10 minutes of standing or head-up tilt test (within 3 minutes for c.e.)
|
Supportive clinical features | Biomarkers |
Motor - Rapid progression within 3 years of motor onset
- Moderate to severe postural instability within 3 years of motor onset
- Craniocervical dystonia induced/exacerbated by levodopa in absence of limb dyskinesia
- Severe speech impairment within 3 years of motor onset
- Severe dysphagia within 3 years of motor onset
- Unexplained Babinski
- Jerky myoclonic postural or kinetic tremor
- Postural deformities (eg, anterocollis, laterocollis, camptocormia)
| Nonmotor - Stridor
- Inspiratory sighs
- Cold discolored hands and feet
- Erectile dysfunction (before age 60 years for c.e.)
- Pathologic laughter or crying
| Brain MRI - Atrophy of putamen, MCP, pons, and/or cerebellum
- Signal decrease of putamen on iron-sensitive sequences
- "Hot cross bun" sign
- Increased diffusivity of putamen and/or MCP
|
Exclusionary features |
- Substantial and persistent beneficial response to dopaminergic medications
- Unexplained anosmia on olfactory testing
- Abnormal cardiac sympathic imaging (123I-MIBG-scintigraphy)
- Fluctuating cognition with early decline in visuospatial abilities
- Recurrent visual hallucinations within 3 years of disease onset
- Dementia within 3 years of disease onset
- Downgaze supranuclear palsy
- Brain MRI findings suggestive of alternative diagnosis (eg, PSP, MS, vascular parkinsonism, symptomatic cerebellar disease)
- Alternative condition known to produce autonomic failure, ataxia, or parkinsonism
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