TABLE 5.
Degrees of diagnostic certainty, obtained by combinations of clinical features and clinical clues
| Diagnostic Certainty | Definition | Combinations | Predominance Type | Abbreviation |
|---|---|---|---|---|
| Definite PSP | Gold standard defining the disease entity | Neuropathological diagnosis | Any clinical presentation | def. PSP |
| Probable PSP | Highly specific, but not very sensitive for PSP | (O1 or O2) + (P1 or P2) | PSP with Richardson’s syndrome | prob. PSP-RS |
| Suitable for therapeutic and biological studies | (O1 or O2) + A1 | PSP with progressive gait freezing | prob. PSP-PGF | |
| (O1 or O2) + (A2 or A3) | PSP with predominant parkinsonism | prob. PSP-P | ||
| (O1 or O2) + C2 | PSP with predominant frontal presentation | prob. PSP-F | ||
| Possible PSP | Substantially more sensitive, but less specific for PSP | O1 | PSP with predominant ocular motor dysfunction | poss. PSP-OM |
| Suitable for descriptive epidemiological studies and clinical care | O2 + P3 | PSP with Richardson’s syndrome | poss. PSP-RS | |
| A1 | PSP with progressive gait freezing | poss. PSP-PGF | ||
| (O1 or O2) + C1 | PSP with predominant speech/language disordera | poss. PSP-SL | ||
| (O1 or O2) + C3 | PSP with predominant CBSa | poss. PSP-CBS | ||
| Suggestive of PSP | Suggestive of PSP, but not passing the threshold for possible or probable PSP | O2 or O3 | PSP with predominant ocular motor dysfunction | s.o. PSP-OM |
| P1 or P2 | PSP with predominant postural instability | s.o. PSP-PI | ||
| Suitable for early identification | O3 + (P2 or P3) | PSP with Richardson’s syndrome | s.o. PSP-RS | |
| (A2 or A3) + (O3, P1, P2, C1, C2, CC1, CC2, CC3, or CC4) | PSP with predominant parkinsonism | s.o. PSP-P | ||
| C1 | PSP with predominant speech/language disorder | s.o. PSP-SL | ||
| C2 + (O3 or P3) | PSP with predominant frontal presentation | s.o. PSP-F | ||
| C3 | PSP with predominant CBS | s.o. PSP-CBS |
The basic features B1+B2+B3 (see Table 1) apply for all probable, possible, and suggestive criteria. Core clinical features are defined by their functional domain (ocular motor dysfunction [O], postural instability [P], akinesia [A], and cognitive dysfunction [C]), and stratified by presumed levels of certainty (1 [highest], 2 [mid], 3 [lowest]) they contribute to the diagnosis of PSP (see Table 2). Supportive clinical clues (CC) are presented in Table 3. Operationalized definitions of clinical features and clinical clues are given in Table 4.
a
Probable 4R-tauopathy (i.e., either PSP or CBD).