Figure 4 Group differences between bvFTD, SD-Left and SD-Right patients on emergent factors from the PCA.

Statistical comparisons run using ANOVA with post hoc comparisons using Sidak corrections indicated significant group differences in Semantic dysfunction factor [Factor 2: F(2,59) = 25.3; P < 0.001; ${\eta }_p^2$ = 0.46] with both SD groups performing significantly poorer than the bvFTD group (all P < 0.001) but comparably to each other (P > 0.1); Executive factor [Factor 4: F(2,59) = 3.1; P = 0.05; ${\eta }_p^2$ = 0.09] where the bvFTD group performed significantly worse than the SD-Right group (P = 0.007) and the Visuospatial factor [Factor 7: F(2,59) = 5.1; P = 0.008; ${\eta }_p^2$ = 0.14] where both bvFTD and SD-Right patients performed poorer than the SD-Left group (both P-values < 0.01), with no significant differences between bvFTD and SD-Right groups (P > 0.1). No other significant differences emerged. All P-values emerging as significant in post hoc comparisons are indicated in figure. Blue horizontal lines indicate the Control lower bound of normality score (i.e. −1.96 SEM from Control performance; see Supplementary Methods for calculation details). bvFTD, behavioural variant frontotemporal dementia; SD, semantic dementia; PCA, principal component analysis; Gen. Cog., General Cognition factor; Exec., Executive factor; Initiat., Initiation factor; Disinhibit., Disinhibition factor; Visuosp., Visuospatial factor.