Atypical Parkinsonism Syndromes

Clinical Characteristics

• The American Academy of Neurology notes that atypical parkinsonism syndromes, including Progressive Supranuclear Palsy (PSP), Multiple System Atrophy (MSA), and Corticobasal Degeneration (CBD), are defined by distinct clinical presentations, pathological findings, and progression patterns, with PSP characterized by postural instability and supranuclear gaze palsy, MSA by prominent autonomic dysfunction, and CBD by asymmetric cortical sensorimotor deficits 1
• PSP syndrome is characterized by postural instability and supranuclear gaze palsy, with varying degrees of cognitive, behavioral, or other movement symptoms 1
• MSA is classified into three clinical subtypes: MSA-P (parkinsonism predominant), MSA-C (cerebellar predominant), and MSA-A (autonomic predominant/Shy-Drager syndrome) 2
• The International Parkinson and Movement Disorder Society recommends considering distinctive clinical features of MSA, including prominent autonomic dysfunction (83% have urinary dysfunction and 75% have symptomatic orthostatic hypotension) 2
• Corticobasal syndrome presents with cortical sensorimotor deficits and cognitive difficulties with asymmetric rigidity and motor dysfunction 1

Pathological Classification

• The National Institute of Neurological Disorders and Stroke states that PSP and CBD are tauopathies (tau protein accumulation) 1
• MSA is a synucleinopathy (α-synuclein accumulation), similar to Parkinson's disease but with different distribution patterns 2

Disease Progression and Prognosis

• The European Federation of Neurological Societies notes that MSA typically has a more rapid progression with shorter survival (approximately 6 years from diagnosis) 2