To examine differences between patients with SD and svPPA, we divided the SD patients into 2 groups.
The overlap between the SD and the svPPA groups is shown in Figure 2a.
Results of the present study also show the validity of the PPA criteria that classified those 15 patients into these 3 subgroups: svPPA group, navPPA group, or lvPPA group.
In this study, 15 of 27 patients with SD did not fulfil the svPPA criteria due to prominent behavioural disturbances.
As it is reported that the background pathology of SD and svPPA is common, (9) there is crucial problem in the 2-step diagnostic process for PPA variants when considering disease-modified treatment in any future study.
The sample included 50 patients with bvFTD, 14 with svPPA, and 22 with nfvPPA diagnosis.
Control subjects were matched with bvFTD, svPPA, and nfvPPA patients (see Table 1).
Contrasts between groups were bvFTD versus controls, nfvPPA + svPPA versus controls, and bvFTD versus nfvPPA + svPPA.
There were no differences among variants (bvFTD, svPPA, and nfvPPA) on FrSBe before or currently (p > 0.05 in all cases).
The results with network-based statistics showed significant differences between the control group and bvFTD, svPPA, nfvPPA, and svPPA + nfvPPA groups.
With respect to results with linguistic variants, there were more differences in nfvPPA than svPPA. The comparison between control and svPPA groups showed only connectivity differences between the right operculum and the left putamen (Figure 1(b) and Table S2).
There were no differences between controls and svPPA patients.