title: Cardiorespiratory fitness and white matter integrity in Alzheimer's disease.
abstract: The objective of this study was to investigate the relationship between cardiorespiratory (CR) fitness and the brain's white matter tract integrity using diffusion tensor imaging (DTI) in the Alzheimer's disease (AD) population. We recruited older adults in the early stages of AD (n = 37; CDR = 0.5 and 1) and collected cross-sectional fitness and diffusion imaging data. We examined the association between CR fitness (peak oxygen consumption [VO2peak]) and fractional anisotropy (FA) in AD-related white matter tracts using two processing methodologies: a tract-of-interest approach and tract-based spatial statistic (TBSS). Subsequent diffusivity metrics (radial diffusivity [RD], mean diffusivity [MD], and axial diffusivity [A × D]) were also correlated with VO2peak. The tract-of-interest approach showed that higher VO2peak was associated with preserved white matter integrity as measured by increased FA in the right inferior fronto-occipital fasciculus (p = 0.035, r = 0.36). We did not find a significant correlation using TBSS, though there was a trend for a positive association between white matter integrity and higher VO2peak measures (p < 0.01 uncorrected). Our findings indicate that higher CR fitness levels in early AD participants may be related to preserved white matter integrity. However to draw stronger conclusions, further study on the relationship between fitness and white matter deterioration in AD is necessary.
authors.affiliation: KU Alzheimer's Disease Center, Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA.|Bioengineering Program, The University of Kansas, Lawrence, KS, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Perea
authors.affiliation: KU Alzheimer's Disease Center, Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA.
authors.forename: E D
authors.initials: ED
authors.lastname: Vidoni
authors.affiliation: KU Alzheimer's Disease Center, Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA.
authors.forename: J K
authors.initials: JK
authors.lastname: Morris
authors.affiliation: KU Alzheimer's Disease Center, Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Graves
authors.affiliation: KU Alzheimer's Disease Center, Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Burns
authors.affiliation: KU Alzheimer's Disease Center, Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA. rhonea@kumc.edu.|Bioengineering Program, The University of Kansas, Lawrence, KS, USA. rhonea@kumc.edu.|Department of Neurology, University of Kansas School of Medicine, 4350 Shawnee Mission Parkway, Fairway, KS, 66205, USA. rhonea@kumc.edu.
authors.forename: R A
authors.initials: RA
authors.lastname: Honea
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D000072599:Cardiorespiratory Fitness; D003430:Cross-Sectional Studies; D056324:Diffusion Tensor Imaging; D005080:Exercise Test; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D057185:Sedentary Behavior; D066127:White Matter / Q000000981:diagnostic imaging*
keywords: Alzheimer’s disease; Diffusion imaging; Exercise; Fitness; Neuroimaging