Table 1.

The language features of PSP-SL, CBS-NAV, and nfvPPA

PSP-SL [10]	CBS-NAV [20]	nfvPPA [35]
At least one of the following features, which has to be persistent (rather than transient): (1) non-fluent/ agrammatic variant of primary progressive aphasia (loss of grammar and/or telegraphic speech or writing), or (2) progressive apraxia of speech (effortful, halting speech with inconsistent speech sound errors and distortions or slow syllabically segmented prosodic speech patterns)	Effortful, agrammatic speech plus at least one of: (1) impaired grammar/sentence comprehension with relatively preserved single-word comprehension, or (2) groping, distorted speech production (apraxia of speech)	At least one of: (1) agrammatism in language production; and (2) effortful, halting speech with inconsistent speech sound errors and distortions (apraxia of speech). PLUS at least two of: (1) impaired comprehension of syntactically complex sentences (2) spared single-word comprehension (3) spared object knowledge

PSP-SL PSP with predominant speech/language disorder, CBS-NAV CBS presenting as nfvPPA, nfvPPA non-fluent/agrammatic variant of primary progressive aphasia