| Diagnostic certainty | Definition | Combinations of clinical features and clinical clues | Predominance type | Abbreviation |
| Definite PSP | Gold standard defining the disease entity. | Neuropathological diagnosis | Any clinical presentation | Definite PSP |
| Probable PSP | Highly specific, but not very sensitive for PSP. Suitable for therapeutic and biological studies. | (O1 or O2) + (P1 or P2) | PSP with Richardson's syndrome (PSP-RS) | Probable PSP-RS |
| (O1 or O2) + A1 | PSP with progressive gait freezing (PSP-PGF) | Probable PSP-PGF | ||
| (O1 or O2) + (A2 or A3) | PSP with predominant parkinsonism (PSP-P) | Probable PSP-P | ||
| (O1 or O2) + C2 | PSP with predominant frontal presentation (PSP-F) | Probable PSP-F | ||
| Possible PSP | Substantially more sensitive, but less specific for PSP. Suitable for descriptive epidemiological studies and clinical care. | O1 | PSP with predominant ocular motor dysfunction (PSP-OM) | Possible PSP-OM |
| O2 + P3 | PSP-RS | Possible PSP-RS | ||
| A1 | PSP-PGF | Possible PSP-PGF | ||
| (O1 or O2) + C1 | PSP with predominant speech/language disorder (PSP-SL)* | Possible PSP-SL | ||
| (O1 or O2) + C3 | PSP with predominant corticobasal syndrome (PSP-CBS)* | Possible PSP-CBS | ||
| Suggestive of PSP | Suggestive of PSP, but not passing the threshold for possible or probable PSP. Suitable for early identification. | O2 or O3 | PSP-OM | Suggestive of PSP-OM |
| P1 or P2 | PSP with predominant postural instability (PSP-PI) | Suggestive of PSP-PI | ||
| O3 + (P2 or P3) | PSP-RS | Suggestive of PSP-RS | ||
| (A2 or A3) + (O3, P1, P2, C1, C2, CC1, CC2, CC3, or CC4) | PSP-P | Suggestive of PSP-P | ||
| C1 | PSP-SL | Suggestive of PSP-SL | ||
| C2 + (O3 or P3) | PSP-F | Suggestive of PSP-F | ||
| C3 | PSP-CBS | Suggestive of PSP-CBS |
