Table 1.
Demographic information and cognitive measures per diagnostic group.
| Characteristic | HCS | MCI | AD | p Value | |
|---|---|---|---|---|---|
| N | 149 | 31 | 26 | N/A | |
| Age, y | 68.93 (5.75) | 73.39 (5.93) | 77.65 (6.10) | 0.000*a,b,c | |
| Gender, M/Fd | 59/90 | 11/20 | 7/19 | 0.455 | |
| Years of education | 14.51 (3.25) | 12.94 (2.95) | 11.12 (2.81) | 0.000* a,b | |
| MMSEe | 29.43 (0.82) | 27.87 (1.77) | 21.46 (3.78) | 0.000* a,b,c | |
| Digit Span Forward | raw | 7.49 (1.78) | 5.90 (1.33) | 5.35 (1.81) | N/A |
| res | 0.00 (0.99) | -0.63 (0.71) | -0.65 (1.16) | 0.000* a,b | |
| Word List Learning | raw | 23.70 (2.87) | 17.13 (4.49) | 12.27 (4.01) | N/A |
| rese | 0.00 (0.99) | -2.25 (1.58) | -3.91 (1.43) | 0.000* a,b,c | |
| Category Fluency | raw | 23.91 (4.74) | 17.71 (5.10) | 11.08 (5.25) | N/A |
| res | 0.00 (0.99) | -1.22 (1.08) | -2.53 (1.15) | 0.000* a,b,c | |
| Letter Fluency | raw | 31.65 (8.93) | 22.58 (10.21) | 13.23 (5.96) | N/A |
| res | 0.00 (0.99) | 0.29 (1.52) | -0.66 (1.12) | 0.004* a,c | |
| Stroop Trial 3 | raw | 28.36 (8.70) | 35.29 (9.94) | 69.04 (48.33) | N/A |
| rese | 0.00 (0.99) | -0.74 (1.01) | -2.74 (2.20) | 0.000* a,b,c | |
| Five-Point Test | raw | 25.96 (7.00) | 18.74 (6.70) | 12.19 (5.27) | N/A |
| res | 0.00 (0.99) | -0.91 (0.87) | -1.70 (0.78) | 0.000* a,b,c | |
| Across-domain IIM | 0.00 (0.63) | -1.37 (0.82) | -2.36 (0.92) | 0.000* a,b,c | |
| Within-domain IIM | 0.00 (0.73) | -0.45 (0.86) | -1.70 (0.99) | 0.000* a,b,c | |
| Across-domain IIVf | 0.91 (0.62) | 0.98 (0.58) | 1.52 (0.75) | 0.001* a,c | |
| Within-domain IIVf | 0.75 (0.55) | 1.01 (0.52) | 1.23 (0.65) | 0.002* a,b |
HCS = healthy control subjects; MCI = mild cognitive impairment; AD = Alzheimer’s disease; N/A = not applicable; MMSE = Mini-Mental State Examination; res = standardized residuals; raw = raw scores; IIM = intraindividual mean; IIV = intraindividual variability. Data are means and standard deviations unless specified otherwise. Standardized residuals of cognitive test scores for MCI and AD were calculated by using parameter estimates for age, education and gender in HCS. *Significant global p value test by analysis of variance unless specified otherwise. Post hoc tests indicated significant differences at p ≤ 0.05 or lower (parametric tests) and p < 0.01 or lower (non-parametric tests) for aHCS vs. AD; bHCS vs. MCI; cMCI vs. AD. dPearson’s X2 test. eKruskal–Wallis test followed by Mann–Whitney test. fAnalyses of covariance, means adjusted for age, gender, education and across- or within-domain IIM.