Table 4.
Principal Factor Loadings on the Severe Impairment Battery (SIB) among Participants in the DS-AD and GP-AD Groups
| GP-AD | DS-AD | ||||||
|---|---|---|---|---|---|---|---|
| Principal Factor | Principal Factor | ||||||
| SIB Domain | Label | PC1 | PC2 | PC3 | PC1 | PC2 | PC3 |
| Social Interaction | SIB-SI | −0.01 | 0.04 | −0.00 | −0.04 | 0.04 | −0.01 |
| Memory | SIB-M | 0.03 | 0.68 | 0.60 | −0.26 | −0.26 | 0.78 |
| Orientation | SIB-O | 0.01 | 0.21 | −0.07 | −0.11 | 0.04 | −0.13 |
| Orientation to Name | SIB-ON | −0.00 | 0.11 | −0.09 | −0.02 | 0.01 | 0.09 |
| Attention | SIB-A | −0.06 | 0.13 | 0.15 | −0.13 | −0.05 | −0.06 |
| Praxis | SIB-PR | 0.09 | 0.50 | −0.77 | −0.14 | −0.87 | −0.40 |
| Language | SIB-L | 0.99 | −0.05 | 0.06 | −0.92 | 0.23 | −0.21 |
| Visuospatial | SIB-VS | −0.02 | 0.45 | −0.06 | −0.16 | −0.28 | 0.39 |
| Construction | SIB-C | 0.02 | 0.10 | 0.08 | −0.11 | 0.20 | 0.04 |
Loadings are reported by domain for the first three principal factors in order of importance based on the proportion of total variation. Signs of the loading are arbitrary. Of importance for interpretation are the relative weightings and differences of signs among the domains. Abbreviations: GP-AD, individuals from the general population with Alzheimer’s disease; DS-AD, persons with Down syndrome and Alzheimer’s disease; PC, Principal factor; SIB, Severe Impairment Battery.