Table 2.
Factor Structure of the New ADAS-cog 2-Factor Analysis for the AD, PDD, and Pooled Patient Populations (Randomized Population a )
| Item | IDEAL and ADENA (AD) | EXPRESS (PDD) | IDEAL, ADENA, and EXPRESS (AD and PDD) a | |||
|---|---|---|---|---|---|---|
| N = 3959 | N = 513 | N = 4472 | ||||
| Factor 1 (4.71) b | Factor 2 (0.80) b | Factor 1 (3.90) b | Factor 2 (0.72) b | Factor 1 (4.56) b | Factor 2 (0.79) b | |
| Word recall | 0.67 | 0.23 | 0.58 | 0.19 | 0.68 | 0.22 |
| Following commands | 0.56 | 0.43 | 0.52 | 0.29 | 0.54 | 0.43 |
| Constructional praxis | 0.47 | 0.19 | 0.52 | 0.18 | 0.45 | 0.21 |
| Naming objects/fingers | 0.53 | 0.36 | 0.43 | 0.08 | 0.53 | 0.33 |
| Ideational praxis | 0.57 | 0.31 | 0.50 | 0.35 | 0.54 | 0.34 |
| Orientation | 0.67 | 0.17 | 0.62 | 0.28 | 0.67 | 0.16 |
| Word recognition | 0.65 | 0.18 | 0.49 | 0.12 | 0.64 | 0.16 |
| Remembering test instructions | 0.54 | 0.43 | 0.58 | 0.44 | 0.55 | 0.42 |
| Spoken language ability | 0.22 | 0.80 | 0.20 | 0.73 | 0.21 | 0.79 |
| Word-finding difficulty | 0.27 | 0.77 | 0.17 | 0.76 | 0.27 | 0.76 |
| Comprehension of spoken language | 0.32 | 0.73 | 0.37 | 0.69 | 0.32 | 0.73 |
Abbreviations: IDEAL, Investigation of transDermal Exelon in ALzheimer’s disease; EXPRESS, EXelon in PaRkinson’s disEaSe dementia Study; ADENA, Alzheimer's Disease with ENA 713; AD, Alzheimer’s disease; ADAS-cog, Alzheimer’s Disease Assessment Scale–cognitive subscale; PDD, Parkinson’s disease dementia.
aOf the randomized population (n = 4540), baseline ADAS-cog data were provided by 4472 patients.
bEigenvalues. Two domains were derived from a factor analysis on the covariance matrix of 11 baseline ADAS-cog items using a varimax rotation. Factors retained had eigenvalues >0.5. Domains took the sum of each item that loaded >0.4; items that loaded on multiple factors were included in the factor with the highest loading.
Items that loaded most highly on the factor are shown in bold.