Table 1.

The role of functional neuroimaging in the differential diagnosis of Parkinsonian syndromes.

	Essential tremor	Idiopathic Parkinson's disease	Multiple system atrophy	Progressive supranuclear palsy	Lewy body dementia
Symptoms	Tremor	Tremor	Tremor	Tremor	Tremor
		Bradykinesia	Bradykinesia	Bradykinesia	Bradykinesia
		Rigidity	Rigidity	Rigidity	Rigidity
		Autonomic Instability	Autonomic Instability	Autonomic Instability	Autonomic Instability Late Visual Hall.
Course	Stable	Progressive	Progressive	Progressive	Progressive
DAT	DAT—normal	DAT—decreased Statistically Significant	DAT- decreased Statistically Significant	DAT—decreased variable	DAT—slightly decreased
Perfusion SPECT or FDG PET	Normal	Increased in putamen Increased in cerebellum Decreased parietal lobes	Decreased in putamen Decreased in cerebellum	Decreased left frontal Decreased left caudate Decreased thalamus Decreased ant. cingulate	Decreased in occipital Decreased in parietal
UPSIT	Normal	Impaired	Normal	Variably impaired	Impaired