%0 Journal Article %J J Alzheimers Dis %D 2018 %T Physical Activity and Hippocampal Sub-Region Structure in Older Adults with Memory Complaints. %A Siddarth, Prabha %A Rahi, Berna %A Emerson, Natacha D %A Burggren, Alison C %A Miller, Karen J %A Bookheimer, Susan %A Lavretsky, Helen %A Dobkin, Bruce %A Small, Gary %A Merrill, David A %K Aged %K Aged, 80 and over %K Cognition %K Cross-Sectional Studies %K Executive Function %K Exercise %K Female %K Geriatric Assessment %K Hippocampus %K Humans %K Magnetic Resonance Imaging %K Male %K Memory %K Memory Disorders %K Middle Aged %K Neuropsychological Tests %X

BACKGROUND: Physical activity (PA) plays a major role in maintaining cognition in older adults. PA has been shown to be correlated with total hippocampal volume, a memory-critical region within the medial temporal lobe (MTL). However, research on associations between PA and MTL sub-region integrity is limited.

OBJECTIVE: To examine the relationship between PA, MTL thickness, and its sub-regions, and cognitive function in non-demented older adults with memory complaints.

METHODS: Twenty-nine subjects aged ≥60 years, with memory complaints were recruited for this cross-sectional study. PA was tracked for 7 days using accelerometers, and average number of steps/day determined. Subjects were categorized into two groups: those who walked ≤4000 steps/day (lower PA) and those with >4000 steps/day (higher PA). Subjects received neuropsychological testing and 3T MRI scans. Nonparametric ANCOVAs controlling for age examined differences between the two groups.

RESULTS: Twenty-six subjects aged 72.7(8.1) years completed the study. The higher PA group (n = 13) had thicker fusiform gyrus (median difference = 0.11 mm, effect size (ES) = 1.43, p = 0.001) and parahippocampal cortex (median difference = 0.12 mm, ES = 0.93, p = 0.04) compared to the lower PA group. The higher PA group also exhibited superior performance in attention and information-processing speed (median difference = 0.90, ES = 1.61, p = 0.003) and executive functioning (median difference = 0.97, ES = 1.24, p = 0.05). Memory recall was not significantly different between the two groups.

CONCLUSION: Older non-demented individuals complaining of memory loss who walked >4000 steps each day had thicker MTL sub-regions and better cognitive functioning than those who walked ≤4000 steps. Future studies should include longitudinal analyses and explore mechanisms mediating hippocampal related atrophy.

%B J Alzheimers Dis %V 61 %P 1089-1096 %8 2018 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/29254088?dopt=Abstract %R 10.3233/JAD-170586