Differentiating Multiple System Atrophy from Progressive Supranuclear Palsy

Clinical Features

The American College of Radiology suggests that vertical supranuclear gaze palsy, early severe falls, and axial-predominant rigidity are characteristic of Progressive Supranuclear Palsy (PSP), whereas prominent early autonomic dysfunction, cerebellar ataxia, and preserved eye movements are characteristic of Multiple System Atrophy (MSA) 1, 2
PSP typically presents with a mean age of 63 years, while MSA presents between 55-65 years of age 1, 2
Axial-predominant rigidity affects axial muscles more than limbs in PSP, distinguishing it from MSA 3
Prominent early autonomic dysfunction, including urinary incontinence and orthostatic hypotension, is significantly more common in MSA than PSP 1, 2
Cerebellar ataxia is a characteristic feature of MSA, particularly in the MSA-C subtype, but also occurs in MSA-P 1, 2
Pyramidal signs are frequently reported in MSA but not characteristic of PSP 1, 2
The disease progression rate is approximately 6 years in MSA, with both conditions progressing more rapidly than idiopathic Parkinson's disease 1, 2

PSP is a tauopathy with abnormal tau protein accumulation, while MSA is a synucleinopathy with alpha-synuclein accumulation in oligodendroglia 1, 2, 4

Assessing eye movements, with vertical supranuclear gaze palsy suggesting PSP and preserved vertical gaze with square-wave jerks suggesting MSA 1, 2, 3
Evaluating fall history, with severe falls within the first year suggesting PSP 1, 2
Assessing autonomic function, with early severe urinary incontinence and orthostatic hypotension suggesting MSA 1, 2
Checking for cerebellar signs, with prominent ataxia and dysmetria suggesting MSA 1, 2