Figure 1.

Scatter plots for hippocampal volume and domain-specific memory performance including all time points for each patient up to 12 months post-RT. The trend line overlays the LOESS fit with the smoothing parameter that minimizes the AICC criterion. Significant associations between imaging parameter and memory test were determined based on the beta coefficient (β₂) derived from the linear mixed effects model with random intercept and slope:

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

Raw memory scores are shown. Hippocampal volumes are shown as mm³.

(A) Smaller left hippocampal volumes were not significantly associated with poorer performance on verbal memory testing (HVLT-R Total Recall β₂= 0.00038, P=.849; HVLT-R Delayed Recall, β₂= 0.00008, P=.935).

(B) Smaller right hippocampal volumes were significantly associated with worse performance on visuospatial memory testing (BVMT-R Total Recall, β₂= 0.004 points/mm³, P=.069; BVMT-R Delayed Recall, β₂= 0.00214 points/mm³, P=.021). Abbreviations: BVMT-R, Brief Visuospatial Memory Test-Revised; HVLT-R, Hopkins Verbal Learning Test-Revised