title: Improved Cardiorespiratory Fitness Is Associated with Increased Cortical Thickness in Mild Cognitive Impairment.
abstract: Cortical atrophy is a biomarker of Alzheimer's disease (AD) that correlates with clinical symptoms. This study examined changes in cortical thickness from before to after an exercise intervention in mild cognitive impairment (MCI) and healthy elders. Thirty physically inactive older adults (14 MCI, 16 healthy controls) underwent MRI before and after participating in a 12-week moderate intensity walking intervention. Participants were between the ages of 61 and 88. Change in cardiorespiratory fitness was assessed using residualized scores of the peak rate of oxygen consumption (V̇O2peak) from pre- to post-intervention. Structural magnetic resonance images were processed using FreeSurfer v5.1.0. V̇O2peak increased an average of 8.49%, which was comparable between MCI and healthy elders. Overall, cortical thickness was stable except for a significant decrease in the right fusiform gyrus in both groups. However, improvement in cardiorespiratory fitness due to the intervention (V̇O2peak) was positively correlated with cortical thickness change in the bilateral insula, precentral gyri, precuneus, posterior cingulate, and inferior and superior frontal cortices. Moreover, MCI participants exhibited stronger positive correlations compared to healthy elders in the left insula and superior temporal gyrus. A 12-week moderate intensity walking intervention led to significantly improved fitness in both MCI and healthy elders. Improved V̇O2peak was associated with widespread increased cortical thickness, which was similar between MCI and healthy elders. Thus, regular exercise may be an especially beneficial intervention to counteract cortical atrophy in all risk groups, and may provide protection against future cognitive decline in both healthy elders and MCI.
authors.affiliation: 1Marquette University,Milwaukee,Wisconsin.
authors.forename: Katherine
authors.initials: K
authors.lastname: Reiter
authors.affiliation: 1Marquette University,Milwaukee,Wisconsin.
authors.forename: Kristy A
authors.initials: KA
authors.lastname: Nielson
authors.affiliation: 3University of Maryland,College Park,Maryland.
authors.forename: Theresa J
authors.initials: TJ
authors.lastname: Smith
authors.affiliation: 3University of Maryland,College Park,Maryland.
authors.forename: Lauren R
authors.initials: LR
authors.lastname: Weiss
authors.affiliation: 3University of Maryland,College Park,Maryland.
authors.forename: Alfonso J
authors.initials: AJ
authors.lastname: Alfini
authors.affiliation: 3University of Maryland,College Park,Maryland.
authors.forename: J Carson
authors.initials: JC
authors.lastname: Smith
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002540:Cerebral Cortex / Q000473:pathology*; D060825:Cognitive Dysfunction / Q000473:pathology* / Q000534:rehabilitation*; D005080:Exercise Test / Q000379:methods*; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D057187:Independent Living; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010101:Oxygen Consumption / Q000502:physiology; D013223:Statistics as Topic; D016896:Treatment Outcome; D016138:Walking
keywords: Aerobic fitness; Aging; Alzheimer’s disease; Cognition; Exercise; Neural plasticity; Physical activity; Structural MRI