Comparing gray matter loss profiles between dementia with Lewy bodies and Alzheimer's disease using cortical pattern matching: diagnosis and gender effects.

We used magnetic resonance imaging (MRI) and cortical pattern matching to map differences in cortical gray matter deficits between Alzheimer's disease (AD) and dementia with Lewy bodies (DLB), and explored the possible influence of gender on these patterns. Twenty-nine patients with AD (age 77.9 +/- 5.5), 16 patients with DLB (76.4 +/- 6.7), and 38 controls (75.3 +/- 6.8) were included. Dementia groups were matched for illness severity. Detailed spatial analyses of gray matter were conducted across the entire cerebral cortex by measuring local proportions of gray matter at thousands of homologous cortical surface locations in each subject and between diagnostic groups. To visualize regional changes, statistical differences were mapped at each cortical surface location in 3D. Main effects of diagnosis demonstrated prominent gray matter differences in orbitofrontal and temporal cortices, where AD exhibited the greatest deficits relative to DLB. Main effects of sex showed less gray matter in men within all group comparisons. Exploratory findings for sex by diagnosis interactions suggest greater gray matter loss in the anterior cingulate for men with AD, relative to controls, AD females, and individuals with DLB. Relative preservation of orbitofrontal cortices in addition to temporal structures may contribute to distinguishing DLB from AD. Further investigation of the influence of gender might provide a more comprehensive understanding of the pathophysiological differences underlying the two forms of dementia.