Fig. 2

Principal component analysis of cognitive scores. A Cognitive z-scores were entered in a principal component analysis (PCA), revealing 3 main cognitive components (cogPC) explaining more than 80% of the variance (left panel). The matrices in the middle panel report the loadings of the PCA. The right matrices report the correlations between cognitive component scores and clinical outcomes in each patient group separately, showing specific-disease involvement. B The first component was related with hippocampal volume in the whole sample (p<0.001), while not significant relationships were reported between the hippocampus and the other component scores (p>0.05). C Significant differences were reported in patients compared to controls in all components. BvFTD patients showed lower scores compared to AD in the second cognitive component (cogPC2). Abbreviations: AD, Alzheimer’s disease; bvFTD, behavioral variant frontotemporal dementia; ROCF, Rey–Osterrieth complex figure test; RAVLT, Rey Auditory Verbal Learning Test; PAL, paired associative test; EK-60F, The Ekman 60-Faces; RMET, Reading the Mind in the Eyes; NPI, neuropsychiatric inventory; FBI, frontal behavioral inventory; IADL, Instrument activity daily life; CDR-SOB, clinical dementia rating—sum of boxes; TIV, total intracranial volume