Table 3.
Summary of the Results from the AD and Control Cohorts
| Variable | AD cohort (n = 91) |
AD + CTRL with plaques (n = 101) |
AD + all CTRL (n = 106) |
|||
|---|---|---|---|---|---|---|
| Linear | One-phase exponential | Linear | One-phase exponential | Linear | One-phase exponential | |
| Cortical thickness (μm) | ||||||
| ΔAICc | 1.804 | NA | NA | |||
| Probability (%) | 71.13 | 28.87 | 100 | Not converged | 100 | Not converged |
| Goodness (R2) | 0.1797 | 0.1831 | 0.2130 | NA | 0.2296 | NA |
| Slope ≠ 0? (P) | <0.0001 | NA | <0.0001 | NA | <0.0001 | NA |
| Spearman's r | −0.3977 | NA | −0.4523 | NA | −0.4649 | NA |
| Spearman′s P | <0.0001 | NA | <0.0001 | NA | <0.0001 | NA |
| Amyloid burden (%) | ||||||
| ΔAICc | 4.347 | 10.83 | 18.23 | |||
| Probability (%) | 10.22 | 89.78 | 0.44 | 99.56 | 0.01 | 99.99 |
| Goodness (R2) | 0.0657 | 0.1093 | 0.2317 | 0.3099 | 0.3117 | 0.4205 |
| Slope ≠ 0? (P) | 0.0142 | NA | <0.0001 | NA | <0.0001 | NA |
| Total amyloid plaques | ||||||
| ΔAICc | 1.761 | 11.96 | 21.72 | |||
| Probability (%) | 29.31 | 70.69 | 0.25 | 99.75 | <0.01 | >99.99 |
| Goodness (R2) | 0.0391 | 0.0575 | 0.2101 | 0.2983 | 0.2952 | 0.4258 |
| Slope ≠ 0? (P) | 0.0602 | NA | <0.0001 | NA | <0.0001 | NA |
| Total astrocytes | ||||||
| ΔAICc | 0.7545 | 3.005 | 3.953 | |||
| Probability (%) | 59.32 | 40.68 | 81.80 | 18.20 | 87.83 | 12.17 |
| Goodness (R2) | 0.1951 | 0.1884 | 0.2433 | 0.2204 | 0.2705 | 0.2428 |
| Slope ≠ 0? (P) | <0.0001 | NA | <0.0001 | NA | <0.0001 | NA |
| Spearman's r | 0.4070 | NA | 0.5037 | NA | 0.5471 | NA |
| Spearman's P | <0.0001 | NA | <0.0001 | NA | <0.0001 | NA |
| Total microglia | ||||||
| ΔAICc | 5.171 | 33.18 | 42.25 | |||
| Probability (%) | 92.99 | 7.01 | >99.99 | <0.01 | >99.99 | <0.01 |
| Goodness (R2) | 0.0960 | 0.0431 | 0.1728 | −0.1489 | 0.2109 | −0.1755 |
| Slope ≠ 0? (P) | 0.0028 | NA | <0.0001 | NA | <0.0001 | NA |
| Spearman's r | 0.3545 | NA | 0.4326 | NA | 0.4728 | NA |
| Spearman's P | 0.0006 | NA | <0.0001 | NA | <0.0001 | NA |
The probability of being correct and the goodness of fit (R2) of both the linear regression and the one-phase exponential association models (or decay, in the case of cortical thickness) are shown for the main neuropathological measures in the AD cohort alone, the AD cohort plus the controls without dementia and with plaques, and the AD cohort plus the entire control cohort. The best-fit model is boldfaced. In the linear regression model, P indicates whether the slope is significantly different from 0. When the linear regression model was the preferred-fit model, the correlation coefficient and the P value from the Spearman's rank correlation test are also shown. For the amyloid burden and the total number of amyloid plaques, the nonlinear model remains the best fit, despite the linear fit yielding a straight line with a slope significantly different from 0 (because of the anchoring effect of controls close to 0). Also, the R2 of the one-phase exponential association model is negative for some neuropathological measures, indicating that the best-fit curve fits the data even worse than a horizontal line. Statistics in Materials and Methods provides further details.
ΔAICc, magnitude of the difference between both fit models; CTRL, control without dementia; NA, not applicable.