Table 3.
Post hoc comparisons of the standardized coefficients for WMH, hippocampal volume, and total brain volume in neuropsychological, neuropsychiatric, and functional decline. Standardized beta coefficients are displayed for the interaction effect between the variable and time since baseline. All outcome raw scores were transformed into z-scores based on the performance of the sample at baseline in order to facilitate effect size comparisons between the variables of interest. The interpretation of the standardized beta coefficients is based on SD unit increases between MRI-derived volumetric measure (i.e., log-transformed WMH, hippocampal volume, total brain volume) and the corresponding outcomes age at baseline, sex, race, years of education, and APOE ε4 carrier status were included as covariates in each model. The overlap in the absolute values of the confidence intervals demonstrated that no significant differences were observed between the three variables
| Variable | Beta | 95% CI | p value |
|---|---|---|---|
| CDR Sum of Boxes | |||
| Log-transformed WMH | 0.12 | [0.06, 0.19] | < 0.01 |
| Hippocampal volume | − 0.19 | [− 0.29, − 0.07] | < 0.01 |
| Total brain volume | − 0.15 | [− 0.23, − 0.06] | < 0.01 |
| Semantic Fluency | |||
| Log-transformed WMH | − 0.03 | [− 0.04, − 0.02] | < 0.01 |
| Hippocampal volume | 0.02 | [0.01, 0.04] | < 0.01 |
| Total brain volume | 0.02 | [0.01, 0.04] | < 0.01 |
| TMT-A | |||
| Log-transformed WMH | 0.03 | [0.02, 0.04] | < 0.01 |
| Hippocampal volume | − 0.03 | [− 0.04, − 0.01] | < 0.01 |
| Total brain volume | − 0.02 | [− 0.04, − 0.01] | < 0.01 |
| TMT-B | |||
| Log-transformed WMH | 0.04 | [0.02, 0.05] | < 0.01 |
| Hippocampal volume | − 0.03 | [− 0.05, − 0.01] | < 0.01 |
| Total brain volume | − 0.03 | [− 0.05, − 0.01] | < 0.01 |
| LM-IA | |||
| Log-transformed WMH | − 0.04 | [− 0.07, − 0.01] | 0.01 |
| Hippocampal volume | 0.03 | [0.01, 0.06] | 0.01 |
| Total brain volume | 0.02 | [− 0.02, 0.04] | 0.23 |
| LM-IIA | |||
| Log-transformed WMH | − 0.03 | [0.06, − 0.00] | 0.02 |
| Hippocampal volume | 0.04 | [0.01, 0.06] | 0.01 |
| Total brain volume | 0.01 | [− 0.02, 0.03] | 0.50 |
| WAIS-R DSC | |||
| Log-transformed WMH | − 0.04 | [− 0.06, − 0.02] | < 0.01 |
| Hippocampal volume | 0.02 | [0.00, 0.03] | 0.03 |
| Total brain volume | 0.02 | [0.01, 0.04] | 0.01 |
| GDS-15 | |||
| Log-transformed WMH | 0.02 | [0.01, 0.04] | < 0.01 |
| Hippocampal volume | − 0.01 | [− 0.03, 0.00] | 0.08 |
| Total brain volume | − 0.01 | [− 0.03, 0.02] | 0.61 |