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. 2015 Feb 10;138(4):1023–1035. doi: 10.1093/brain/awv007

Table 2.

Predictive models of longitudinal change in functional MRI, hippocampal volume, MMSE and CDR

Dependent variable:
 Functional MRI
 Hippocampal volume
 MMSE
 CDRSB
Number of observations:
 180
 171
 147
 148
Estimate P-value Estimate P-value Estimate P-value Estimate P-value
I LM models with only Time: −0.029 0.062# −115.440 <0.001*** −0.267 0.028* 0.303 <0.001***
II LM models with amyloid-β:
Time −0.016 0.539 −190.980 <0.001*** −0.604 0.001** 0.62 <0.001***
Amyloid-β 0.144 0.044* −885.696 0.024* −1.198 0.079# 0.60 0.012*
Amyloid-β × Time 0.019 0.543 −125.880 <0.001*** −0.565 0.019* 0.56 <0.001***
III LM models with amyloid-β, age, sex:
Time −0.013 0.572 −224.995 <0.001*** −0.384 0.755 0.654 0.085#
Amyloid-β 0.153 0.042* −744.046 0.029* −1.244 0.079# 0.648 0.092#
Age −0.003 0.482 −50.623 0.023* 0.027 0.549 −0.034 0.177
Sex 0.035 0.698 1242.721 0.004** −0.279 0.745 −0.082 0.860
Amyloid-β × Time 0.014 0.689 −127.572 <0.001*** −0.613 0.017* 0.575 <0.001***
Age × Time 0.001 0.616 1.271 0.473 0.000 0.997 −0.004 0.571
Sex × Time −0.007 0.850 41.070 0.202 −0.314 0.299 −0.035 0.802

The top row shows estimates from four linear mixed-effects (LM) models (Model I) with only time across all patients with MCI. The middle row shows estimates from four linear mixed models (Model II) with time (in years) and amyloid-β group as predictors without covariates. The bottom row shows the estimate from four linear mixed models (Model III) with additional covariates for age, gender and their effect by time. The first column shows models with hippocampal functional MRI activity as the dependent variable. The second column shows models with adjusted hippocampal volume, the third column shows models with Mini-Mental State Exam (MMSE) scores and the fourth column with Clinical Dementia Ratings Sum of Boxes scores (CDRSB).

Amyloid-β and sex are a dichotomous variable and age, functional MRI and hippocampal volume are continuous. Aβ− MCIs were used as the reference group for amyloid-β. Females are used as the reference group for sex. Age, as a control variable, was centred at the group mean. Significant at #P < 0.10 (trending), *P < 0.05, **P < 0.01 and ***P < 0.001.