NINDS criteria for possible PSP
- Gradually progressive disorder with onset aged 40 years or older.
- Either vertical supra nuclear palsy or both slowing of vertical saccades and prominent postural instability with falls in the first year of onset.
- No evidence of other diseases that can explain the clinical features.
Criteria for probable PSP
Vertical supranuclear palsy with prominent postural instability, falls in the first year of onset, and other features of possible PSP, as follows:
- Symmetric proximal greater than distal akinesia or rigidity.
- Abnormal neck posture, especially retrocollis.
- Poor or absent response of parkinsonism to levodopa therapy.
- Early dysphagia and dysarthria.
- Early cognitive impairment with at least 2 of the following: apathy, abstract thought impairment, decreased verbal fluency, imitation behavior, or frontal release signs.
Criteria for definite PSP are as follows:
- History of probable or possible PSP.
- Histopathologic evidence that is typical of the disease.
