Functional expressions of the aging brain.

In the conventional view, aging of the brain is associated with atrophy vascular abnormalities and loss of volume in hippocampus and amygdala. Cognitively, aging is associated with slowing of processing and memory loss. However, many studies of aging do not examine the cases to exclude demented people. The nutrition and memory in the homebound elderly study (NAME) excluded cases clinically diagnosed as having dementia. Cortical atrophy based on MRI ratings was significantly correlated with vascular disease, white matter hyperintensities, processing speed, and memory but not hippocampus and amygdala volume. Renal function and homocysteine were also associated with cortical atrophy but not with the cognitive variables. In conclusion, brain atrophy of aging in the absence of dementia is related to vascular disease but not hippocampal atrophy. Studies of nutritional interventions should consider using MRI atrophy rather than cognition as outcome.