Estimated components of model (8) with ±2 pointwise standard errors, using Ivanescu et al. (2012). Coefficient surfaces are color-coded for sign and pointwise significance (95%): blue if sig. < 0, light blue if < 0, light red if > 0, red if sig. > 0. Top row, left to right: mean FA-CCA for healthy (blue, dotted) versus MS (red, solid) females; mean FA-CCA for female (purple, solid) and male (green, dotted) MS patients; estimated effect of age-at-visit . Bottom row, left to right: Estimated coefficient surfaces , , , .