Table 4.

Interactions between imaging biomarkers and time

Right-hemispheric Structure	Imaging Biomarker	BVMT-R Total Recall: β Interaction*	P-value	BVMT-R Delayed Recall: β Interaction	P-value
Hippocampus	Volume	0.0002	0.548	−.0001	0.405
Entorhinal WM	FA	−7.547	0.102	−2.450	0.188
	MD	5,523	0.021†	2,868	0.004†
Parahippocampal WM	FA	−1.788	0.705	−3.378	0.067
	MD	3,504	0.262	1,450	0.213
Temporal Pole WM	FA	−4.166	0.380	−4.350	0.024†
	MD	1,955	0.424	1,905	0.087
Left-hemispheric Structure	Imaging Biomarker	HVLT-R Total Recall: β Interaction	P-value	HVLT-R Delayed Recall:	P-value
Hippocampus	Volume	−0.0001	0.730	−0.00001	0.467
Entorhinal WM	FA	2.411	0.599	−1.095	0.641
	MD	408.2	0.923	808.0	0.690
Parahippocampal WM	FA	1.423	0.773	1.225	0.629
	MD	−7,336	0.089	−2,916	0.197
Temporal Pole WM	FA	0.4000	0.939	−0.075	0.976
	MD	−4,782	0.174	−3,029	0.098

^*

Where the interaction coefficient is β₃ in the following linear mixed effects model:

$${\mathrm{Memory}\mathrm{Scores}}_{\mathrm{ij}}=({\beta }_0{+\mathrm{b}}_{0\mathrm{i}})+({\beta }_1{\text{+b}}_{1\mathrm{i}}){\mathrm{Month}}_{\mathrm{j}}+{\beta }_2{\mathrm{Imaging}+\beta }_3\mathrm{Imaging}\times {\mathrm{Month}}_{\mathrm{j}}{+\mathrm{e}}_{\mathrm{ij}}$$

where b_0i = subject-specific random intercept, b_1i = random slope, and e_ij = subject error. The β₃ interaction coefficient has the units: volume, points/(month*mm³); FA, points/month; MD, points/(month*mm²/s)

^†P-value significant at alpha = 0.05