The neuropathological assessment procedures used have been described extensively1,4,5 and followed CERAD consensus recommendations.10,31 Standardized representative blocks from the neocortex (superior and midfrontal gyrus, orbital cortex, superior temporal gyrus, inferior parietal lobule of the parietal cortex, and calcarine cortex), basal ganglia with basal forebrain, amygdala, hippocampus (rostral and caudal levels with adjacent entorhinal, parahippocampal, and inferior temporal cortex), rostral cingulated gyrus, corpus striatum, thalamus, midbrain, pons, medulla, cerebellar vermis, and lateral cerebellar hemisphere were examined using hematoxylin-eosin, modified Bielschowsky, and modified thioflavin S stains. Persons with Lewy body formation in the substantia nigra or locus ceruleus underwent anti-ubiquitin or α-synuclein staining of representative cerebral cortical sections. Neuropathological assessments were conducted blindly (D. Purohit and D. Perl) to all clinical and psychometric data. Every person was evaluated for the extent of neuropathological lesions using the CERAD neuropathological battery10,31 for the extent of NPs and NFTs using a 4-point scale (0 indicates none; 1, sparse; 3, moderate;and 5, frequent). In addition, quantitative data regarding the density of NPs that were collected in 5 cortical regions using previously published methods1,4,5 were expressed as mean plaque density per square millimeter for that region: the midfrontal gyrus (Brodmann area 9), orbital frontal cortex (Brodmann area 45/47), superior temporal gyrus (Brodmann area 21/22), inferior parietal lobule (Brodmann area 39), and calcarine cortex (Brodmann area 17). The primary rating variables used in the analyses reported here were densities of NPs and NFTs in the entorhinal cortex, hippocampus, amygdala, and the neocortical regions. Density estimates of NPs and NFTs from the subcortical fields did not substantively contribute to the results described1,4,5 and were not included in analyses.