## 4 Discussion  
This study tested the production of syntactically complex sentences in svPPA and its relationship to demographic and clinical data as well as to general language and cognitive abilities. Last but not least, the relation of performance in the production of complex sentences to hypoperfusion of specific brain areas was also addressed. We found that there was a large individual variability in our dataset, although it was admittedly relatively small. Half of the patients failed to produce the target responses, but even these patients did produce grammatical sentences. This is in accordance with previous studies that indicate spared syntax in svPPA, as manifested by the number of grammatically well-formed sentences in spontaneous speech [5; 11] or constrained tasks [15]. On the other hand, some patients failed to produce the target structure in this constrained task, which suggests some subtle deficit, especially given the fact that these structures are mastered by children and, importantly, tested by means of elicited production tasks [34; 35]. This finding enhances the view that constrained tasks might provide better insight concerning sentence production in svPPA. Our analysis indicates that performance in the sentence production test is predicted by the performance in the comprehension, but not the production, part of the BDAE. This finding indicates that the ability to handle complex syntactic processes has a language \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Predictor** & **Estimate (b)** & **Standard Error** & **z-Value** & \(p\)**-Value** \\ \hline Intercept & 0.993 & 3.52 & 0.28 & 0.78 \\ \hline Left Frontal & \(-\)3.028 & 3.567 & \(-\)0.85 & 0.4 \\ \hline Left Medial Temporal & 20.23 & 6.6 & 3.08 & 0.0021 \\ \hline Left Lateral Temporal & \(-\)15.8 & 5.4 & \(-\)2.93 & 0.0034 \\ \hline \hline \end{tabular} Note: R\({}^{2}\) = 0.11 ([PERSON] and [PERSON]), 0.13 ([PERSON] and Snell), 0.18 ([PERSON]), Model x\({}^{2}\) (1) = 11, \(p\) = 0.001.  
\end{table} 
Table 6: Estimates, x\({}^{2}\) and R\({}^{2}\) of the best-fitted model for the left hemisphere. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Predictor** & **Estimate (b)** & **Standard Error** & **z-Value** & \(p\)**-Value** \\ \hline Intercept & 0.694 & 4.25 & 0.16 & 0.87 \\ \hline Right Frontal & \(-\)0.132 & 4.11 & \(-\)0.03 & 0.97 \\ \hline Right Medial Temporal & \(-\)43.6 & 12.89 & \(-\)3.39 & 0.0007 \\ \hline Right Lateral Temporal & 40.25 & 12.7 & 3.17 & 0.0015 \\ \hline \hline \end{tabular} Note: R\({}^{2}\) = 0.23 ([PERSON] and [PERSON]), 0.26 ([PERSON] and [PERSON]), 0.36 ([PERSON]), Model x\({}^{2}\) (1)= 18, \(p\) < 0.001.  
\end{table} 
Table 7: Estimates, x\({}^{2}\) and R\({}^{2}\) of the best-fitted model for the right hemisphere. component but that the deficit is not modality-specific. The lack of relation between scores in the ACE-R and performance in the task is in accordance with the findings of [PERSON] et al. [14], although their study was longitudinal and focused on the relation between the decline in the Mini Mental State Examination and the decline in language production across time. Taken together, it seems that the ability to produce complex sentences in svPPA is related to some aspects of their general language abilities but not to their cognitive abilities. Crucially, our finding indicates that specific language deficits in the domain of complex syntax are manifested in patients with svPPA independently of their general cognitive abilities. Concerning the relationship between the production of complex sentences and brain hypoperfusion, the present dataset points to a lack of a linear relationship between the two. Our analysis addressed the relationship between the performance in this task and hypoperfusion in brain regions that have been associated with syntactic deficits as well as in brain regions that have been associated with the language pattern in svPPA. Neither of them was a predictor.