Table 1.

Defining clinical features of the PSP phenotypes based on MDS-PSP criteria.

Clinical domains	Certainty level
	Level 1	Level 2	Level 3
Ocular motor dysfunction	O1	O2	O3
	Vertical supranuclear gaze palsy	Slow vertical saccades	Macro square wave jerks or eyelid opening apraxia
Postural instability	P1	P2	P3
	Repeated unprovoked falls during the first 3 years of disease	Falls on pull-test during the first 3 years of disease	Three or more steps backwards on pull-test during the first 3 years of disease
Akinesia	A1	A2	A3
	Progressive gait freezing during the first 3 years of disease	Levodopa resistant bradykinesia with axial-dominant rigidity	Parkinsonism (bradykinesia and rigidity) with or without: tremor/asymmetry/levodopa response
Cognitive dysfunction	C1	C2	C3
	Speech/language disorders	Frontal cognitive/behavioral presentation	Corticobasal syndrome