Physical activity, brain tissue microstructure, and cognition in older adults

Objective To test whether postmortem MRI captures brain tissue characteristics that mediate the association between physical activity and cognition in older adults. Methods Participants (N = 318) were older adults from the Rush Memory and Aging Project who wore a device to quantify physical activity and also underwent detailed cognitive and motor testing. Following death, cerebral hemispheres underwent MRI to quantify the transverse relaxation rate R2, a metric related to tissue microstructure. For analyses, we reduced the dimensionality of the R2 maps from approximately 500,000 voxels to 30 components using spatial independent component analysis (ICA). Via path analysis, we examined whether these R2 components attenuated the association between physical activity and cognition, controlling for motor abilities and indices of common brain pathologies. Results Two of the 30 R2 components were associated with both total daily physical activity and global cognition assessed proximate to death. We visualized these components by highlighting the clusters of voxels whose R2 values contributed most strongly to each. One of these spatial signatures spanned periventricular white matter and hippocampus, while the other encompassed white matter of the occipital lobe. These two R2 components partially mediated the association between physical activity and cognition, accounting for 12.7% of the relationship (p = .01). This mediation remained evident after controlling for motor abilities and neurodegenerative and vascular brain pathologies. Conclusion The association between physically activity and cognition in older adults is partially accounted for by MRI-based signatures of brain tissue microstructure. Further studies are needed to elucidate the molecular mechanisms underlying this pathway.

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Physical activity, common brain pathologies, and cognition in community-dwelling older adults

Neurology ◽

10.1212/wnl.0000000000006954 ◽

2019 ◽

Vol 92 (8) ◽

pp. e811-e822 ◽

Cited By ~ 11

Author(s):

Aron S. Buchman ◽

Lei Yu ◽

Robert S. Wilson ◽

Andrew Lim ◽

Robert J. Dawe ◽

...

Keyword(s):

Physical Activity ◽

Older Adults ◽

Confidence Interval ◽

Sex Education ◽

Daily Activity ◽

Molecular Mechanisms ◽

Community Setting ◽

Community Dwelling ◽

Sensitivity Analyses ◽

Motor Abilities

ObjectiveTo examine the associations of physical activity, Alzheimer disease (AD), and other brain pathologies and cognition in older adults.MethodsWe studied 454 brain autopsies from decedents in a clinical-pathologic cohort study. Nineteen cognitive tests were summarized in a global cognitive score. Total daily physical activity summarized continuous multiday recordings of activity during everyday living in the community setting. A global motor ability score summarized 10 supervised motor performance tests. A series of regression analyses were used to examine associations of physical activity, AD, and other brain pathologies with global cognition proximate to death controlling for age, sex, education, and motor abilities.ResultsHigher levels of total daily activity (estimate 0.148, 95% confidence interval 0.053–0.244, SE 0.049,p= 0.003) and better motor abilities (estimate 0.283, 95% confidence interval, 0.175–0.390, SE 0.055,p< 0.001) were independently associated with better cognition. These independent associations remained significant when terms for AD and other pathologies were added as well as in sensitivity analyses excluding cases with poor cognition or dementia. Adding interaction terms, the associations of total daily activity and motor abilities with cognition did not vary in individuals with and without dementia. The associations of AD and other pathologies with cognition did not vary with the levels of total daily activity or motor abilities.ConclusionsPhysical activity in older adults may provide cognitive reserve to maintain function independent of the accumulation of diverse brain pathologies. Further studies are needed to identify the molecular mechanisms underlying this potential reserve and to ensure the causal effects of physical activity.

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The Relations Between Physical Activity Level, Executive Function, and White Matter Microstructure in Older Adults

Journal of Physical Activity and Health ◽

10.1123/jpah.2021-0012 ◽

2021 ◽

pp. 1-13

Author(s):

Marissa A. Gogniat ◽

Catherine M. Mewborn ◽

Talia L. Robinson ◽

Kharine R. Jean ◽

L. Stephen Miller

Keyword(s):

Physical Activity ◽

Older Adults ◽

Executive Function ◽

White Matter ◽

Diffusion Tensor ◽

Vigorous Physical Activity ◽

Neuropsychological Testing ◽

Activity Level ◽

Average Intensity ◽

Age Related

The population of older adults is increasing, indicating a need to examine factors that may prevent or mitigate age-related cognitive decline. The current study examined whether microstructural white matter characteristics mediated the relation between physical activity and executive function in older adults without any self-reported psychiatric and neurological disorders or cognitive impairment (N = 43, mean age = 73 y). Physical activity was measured by average intensity and number of steps via accelerometry. Diffusion tensor imaging was used to examine microstructural white matter characteristics, and neuropsychological testing was used to examine executive functioning. Parallel mediation models were analyzed using microstructural white matter regions of interest as mediators of the association between physical activity and executive function. Results indicated that average steps was significantly related to executive function (β = 0.0003, t = 2.829, P = .007), while moderate to vigorous physical activity was not (β = 0.0007, t = 1.772, P = .08). White matter metrics did not mediate any associations. This suggests that microstructural white matter characteristics alone may not be the mechanism by which physical activity impacts executive function in aging.

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Prospective associations between physical activity levels and white matter integrity in older adults: results from the MAPT study

Maturitas ◽

10.1016/j.maturitas.2020.04.012 ◽

2020 ◽

Vol 137 ◽

pp. 24-29

Author(s):

Mathieu Maltais ◽

Yves Rolland ◽

Katherine Boisvert-Vigneault ◽

Lisa Perus ◽

Jean-François Mangin ◽

...

Keyword(s):

Physical Activity ◽

Older Adults ◽

White Matter ◽

White Matter Integrity ◽

Activity Levels ◽

Physical Activity Levels

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Association Between Brain Volumes and Patterns of Physical Activity in Community-Dwelling Older Adults

The Journals of Gerontology Series A ◽

10.1093/gerona/glaa294 ◽

2020 ◽

Author(s):

Amal A Wanigatunga ◽

Hang Wang ◽

Yang An ◽

Eleanor M Simonsick ◽

Qu Tian ◽

...

Keyword(s):

Physical Activity ◽

Older Adults ◽

White Matter ◽

Brain Structure ◽

Community Dwelling ◽

Sensitivity Analyses ◽

Intracranial Volume ◽

Accelerometer Data ◽

Brain Volumes ◽

Cognitively Normal

Abstract Background Larger brain volumes are often associated with more free-living physical activity (PA) in cognitively normal older adults. Yet, whether greater brain volumes are associated with more favorable (less fragmented) PA patterns, and whether this association is stronger than with total PA, remains unknown. Methods Brain magnetic resonance imaging and wrist-worn accelerometer data were collected in 301 participants (mean age = 77 [SD = 7] years, 59% women) enrolled in the Baltimore Longitudinal Study of Aging. Linear regression models were fit to examine whether brain volumes (cc) were cross-sectionally associated with: (a) total daily PA minutes and (b) activity fragmentation (mean number of PA bouts / total PA minutes × 100). Sensitivity analyses were conducted by adjusting for counterpart PA variables (eg, fragmentation covariate included in the PA minutes model). Results Greater white matter volumes in the parietal and temporal lobes were associated with higher daily PA minutes (2.6 [SE = 1.0] and 3.8 [0.9] min/day, respectively; p < .009 for both) after adjusting for demographics, behavioral factors, medical conditions, gait speed, apolipoprotein E e4 status, and intracranial volume. Greater temporal white matter volume was associated with lower fragmentation (−0.16% [0.05], p = .003). In sensitivity analyses, observed associations between brain volumes and daily PA minutes remained significant while associations with fragmentation no longer remained significant. Conclusions Our results suggest white matter brain structure in cognitively normal older adults is associated with the total amount of PA and, to a lesser extent, the PA accumulation patterns. More work is needed to elucidate the longitudinal relationship between brain structure and function and PA patterns with aging.

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Late‐life physical activity relates to brain tissue synaptic integrity markers in older adults

Alzheimer s & Dementia ◽

10.1002/alz.12530 ◽

2022 ◽

Author(s):

Kaitlin Casaletto ◽

Alfredo Ramos‐Miguel ◽

Anna VandeBunte ◽

Molly Memel ◽

Aron Buchman ◽

...

Keyword(s):

Physical Activity ◽

Older Adults ◽

Brain Tissue ◽

Late Life

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Physical activity, motor function, and white matter hyperintensity burden in healthy older adults

Neurology ◽

10.1212/wnl.0000000000001417 ◽

2015 ◽

Vol 84 (13) ◽

pp. 1294-1300 ◽

Cited By ~ 33

Author(s):

D. A. Fleischman ◽

J. Yang ◽

K. Arfanakis ◽

Z. Arvanitakis ◽

S. E. Leurgans ◽

...

Keyword(s):

Physical Activity ◽

Older Adults ◽

White Matter ◽

Motor Function ◽

White Matter Hyperintensity ◽

Healthy Older Adults

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Sweat the Fall Stuff: Physical Activity Moderates the Association of White Matter Hyperintensities With Falls Risk in Older Adults

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2021.671464 ◽

2021 ◽

Vol 15 ◽

Author(s):

Rachel A. Crockett ◽

Ryan. S. Falck ◽

Elizabeth Dao ◽

Chun Liang Hsu ◽

Roger Tam ◽

...

Keyword(s):

Physical Activity ◽

Older Adults ◽

White Matter ◽

White Matter Hyperintensities ◽

Public Health Problem ◽

Community Dwelling ◽

Major Public Health Problem ◽

Cross Sectional ◽

Falls Risk ◽

Experienced Radiologist

Background: Falls in older adults are a major public health problem. White matter hyperintensities (WMHs) are highly prevalent in older adults and are a risk factor for falls. In the absence of a cure for WMHs, identifying potential strategies to counteract the risk of WMHs on falls are of great importance. Physical activity (PA) is a promising countermeasure to reduce both WMHs and falls risk. However, no study has yet investigated whether PA attenuates the association of WMHs with falls risk. We hypothesized that PA moderates the association between WMHs and falls risk.Methods: Seventy-six community-dwelling older adults aged 70–80 years old were included in this cross-sectional study. We indexed PA using the Physical Activity Score for the Elderly (PASE) Questionnaire. Falls risk was assessed using the Physiological Profile Assessment (PPA), and WMH volume (mm3) was determined by an experienced radiologist on T2-weighted and PD-weighted MRI scans. We first examined the independent associations of WMH volume and PASE score with PPA. Subsequently, we examined whether PASE moderated the relationship between WMH volume and PPA. We plotted simple slopes to interpret the interaction effects. Age, sex, and Montreal Cognitive Assessment (MoCA) score were included as covariates in all models.Results: Participants had a mean age of 74 years (SD = 3 years) and 54 (74%) were female. Forty-nine participants (66%) had a Fazekas score of 1, 19 (26%) had a score of 2, and 6 (8%) a score of 3. Both PASE (β = −0.26 ± 0.11; p = 0.022) and WMH volume (β = 0.23 ± 0.11; p = 0.043) were each independently associated with PPA score. The interaction model indicated that PASE score moderated the association between WMH volume and PPA (β = −0.27 ± 0.12; p = 0.030), whereby higher PASE score attenuated the association between WMHs and falls risk.Conclusion: PA is an important moderator of falls risk. Importantly, older adults with WMH can reduce their risk of falls by increasing their PA.

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Linking objective measures of physical activity and capability with brain structure in healthy community dwelling older adults

10.1101/2021.01.28.21250529 ◽

2021 ◽

Author(s):

Anne-Marthe Sanders ◽

Geneviève Richard ◽

Knut Kolskår ◽

Kristine M. Ulrichsen ◽

Tobias Kaufmann ◽

...

Keyword(s):

Physical Activity ◽

Older Adults ◽

White Matter ◽

Cognitive Aging ◽

Walking Speed ◽

Community Dwelling ◽

Brain Morphology ◽

Brain Health ◽

Physical Capability ◽

Brain Age

AbstractMaintaining high levels of daily activity and physical capability have been proposed as important constituents to promote healthy brain and cognitive aging. Studies investigating the associations between brain health and physical activity in late life have, however, mainly been based on self-reported data or measures designed for clinical populations. In the current study, we examined cross-sectional associations between physical activity, recorded by an ankle-positioned accelerometer for seven days, physical capability (grip strength, postural control, and walking speed), and neuroimaging based surrogate markers of brain health in 122 healthy older adults aged 65-88 years. We used a multimodal brain imaging approach offering two complementary structural MRI based indicators of brain health: white matter diffusivity and coherence based on diffusion tensor imaging and subcortical and global brain age based on brain morphology inferred from T1-weighted MRI data. The analyses revealed a significant association between global white matter fractional anisotropy (FA) and walking speed, indicating higher white matter coherence in people with higher pace. We also found a significant interaction between sex and brain age on number of daily steps, indicating younger-appearing brains in more physically active women, with no significant associations among men. These results provide insight into the intricate associations between different measures of brain and physical health in old age, and corroborate established public health advice promoting physical activity.

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