Figure.
The significant areas of annual atrophy in our amyotrophic lateral sclerosis (ALS) population are highlighted and color-coded by neuroanatomical area on the cortex of a population-specific template. Atrophy was measured by a fine-grained quantitative structural analysis based on diffeomorphic image normalization. Such methods quantify structure in the spirit of voxel-based morphometry, but with higher anatomic fidelity and sensitivity.4,5 Significance is defined as a voxelwise false discovery rate-corrected P value of .05 with contiguous gray matter voxel clusters larger than 500 voxels. These areas indicate regions of cortical gray matter undergoing annual atrophy that are consistently greater in ALS than in the age- and education-matched elderly control population. In contrast, a cross-sectional morphometric comparison of the elderly and motor neuron degeneration cortical volumes in this cohort produced no significant effects.