Three-dimensional stereotactic surface projection in the statistical analysis of single photon emission computed tomography data for distinguishing between Alzheimer’s disease and depression

Table 2 Factor loading after varimax rotation

Factors	Factor 1	Factor 2	Factor 3
Age	0.103	0.171	-0.504
Sex	0.061	0.960	-0.107
HAM-D	0.135	0.241	0.350
MMSE	-0.679	-0.178	0.399
CGI	0.763	-0.082	-0.048
AD regions	0.674	0.078	0.063
Depression regions	0.523	0.119	0.042

Factor 1 was interpreted as indicating a tendency for AD (negative correlation with MMSE score and positive correlations with CGI-S score and maximum Z-scores of the AD-associated and depression-associated regions). Factor 2 was interpreted as indicating a tendency for pseudo-dementia (more marked in women; positive correlations with age and HAM-D score and negative correlation with MMSE). Factor 3 was interpreted as indicating a depressive tendency (negative correlation with age and positive correlations with HAM-D and MMSE scores). Colored columns represent significant correlation between the variables and Factors. HAM-D: Hamilton Rating Scale for Depression; MMSE: Minimal Mental State Examination; CGI: Clinical Global Impression; AD: Alzheimer’s disease.