### Syntactic Abilities in svPPA I: Manifestation  
Insight about the language abilities in svPPA have been gained through comparison with healthy controls and/or patients with nf/a PPA, whose prominent symptom is a deficit in the domain of syntax, as mentioned above. Data from connected speech reveal a complex pattern of language performance concerning syntax in svPPA, which suggests that some aspects are impaired whereas others are preserved. For instance, [PERSON] et al. [11] did not find differences between svPPA patients and healthy controls concerning grammatical errors. Likewise, [PERSON] et al. [5] found that svPPA patients presented a profile that was similar to that of healthy controls concerning the proportion of grammatical sentences; however, their performance did not differ either from the agrammatic PPA patients or from the controls with respect to the proportion of verbs with correct number of objects and verb morphology. Similarly, [PERSON] et al. [12] report that their svPPA patients produced shorter sentences but more embedded sentences than the controls and made few syntactic errors of a paragrammatic nature, e.g., incorrect usage of endings rather than omissions, which is a linguistic marker of agrammatism (at least in some languages, such as English). [PERSON] et al. [13] conducted a principal component analysis on spontaneous speech samples of nfPPA and svPPA and found that the svPPA and nfPPA differed from healthy controls concerning lexical richness and syntactic complexity, respectively, but the two PPA groups were not different from each other in any factor. [PERSON] et al. [14] provide evidence that a syntactic impairment can appear in svPPA also in spontaneous speech, manifested as a smaller proportion of well-formed and dependent clauses (as a measurement of syntactic complexity).  
Spontaneous speech gives insights into language abilities in naturalistic contexts, but it is also problematic because it does not constrain speakers. Speakers with language impairment may circumvent difficulties by avoiding structures that are challenging. Consequently, they may not manifest syntactic deficits, only because they have developed compensational strategies in spontaneous speech. Indeed, studies that addressed sentence production and in particular, the production of complex sentences, suggest some impairment in the syntactic domain. For instance, [PERSON] et al. [15] compared the three PPA types concerning their ability to produce several types of structures such as sentences with intransitive, transitive and distransitive verbs, passives and dependent clauses. They used an elicitation task whereby the participants were prompted to respond to a short story, and crucially, wh-questions (questioning _where_ and _how_) were also tested. The results showed that svPPA patients attempted significantly less frequently than the controls to produce the target structures, and they did not differ from the nf/aPPA in this respect. Nevertheless, they did not differ from the controls concerning either the correctness of the attempted structures nor the overall frequency of syntactic errors (independently of attempts at the target structure). [PERSON] et al. [16] used a similar task and found that svPPA did not differ from either non-fluent PPA or healthy controls concerning the proportion of grammatical responses, although the numerical difference with the latter was large (92 vs. 57%).