School of Public Health

Permanent URI for this communityhttp://hdl.handle.net/1903/1633

The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

Note: Prior to July 1, 2007, the School of Public Health was named the College of Health & Human Performance.

Browse

Subject: search.filters.subject.cognition

Search Results

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Physical Activity and Brain Function in Older Adults at Increased Risk for Alzheimer’s Disease
    (MDPI, 2013-01-14) Smith, J. Carson; Nielson, Kristy A.; Woodard, John L.; Seidenberg, Michael; Rao, Stephen M.
    Leisure-time physical activity (PA) and exercise training are known to help maintain cognitive function in healthy older adults. However, relatively little is known about the effects of PA on cognitive function or brain function in those at increased risk for Alzheimer’s disease through the presence of the apolipoproteinE epsilon4 (APOE-ε4) allele, diagnosis of mild cognitive impairment (MCI), or the presence of metabolic disease. Here, we examine the question of whether PA and exercise interventions may differentially impact cognitive trajectory, clinical outcomes, and brain structure and function among individuals at the greatest risk for AD. The literature suggests that the protective effects of PA on risk for future dementia appear to be larger in those at increased genetic risk for AD. Exercise training is also effective at helping to promote stable cognitive function in MCI patients, and greater cardiorespiratory fitness is associated with greater brain volume in early-stage AD patients. In APOE-ε4 allele carriers compared to non-carriers, greater levels of PA may be more effective in reducing amyloid burden and are associated with greater activation of semantic memory-related neural circuits. A greater research emphasis should be placed on randomized clinical trials for exercise, with clinical, behavioral, and neuroimaging outcomes in people at increased risk for AD.
  • Thumbnail Image
    Item
    Effects of acute aerobic exercise on mnemonic discrimination performance in older adults
    (Cambridge University Press, 2022-08-15) Callow, Daniel D.; Pena, Gabriel S.; Stark, Craig E. L.; Smith, J. Carson
    Objectives:Ample evidence suggests exercise is beneficial for hippocampal function. Furthermore, a single session of aerobic exercise provides immediate benefits to mnemonic discrimination performance, a highly hippocampal-specific memory process, in healthy younger adults. However, it is unknown if a single session of aerobic exercise alters mnemonic discrimination in older adults, who generally exhibit greater hippocampal deterioration and deficits in mnemonic discrimination performance. Methods: We conducted a within subject acute exercise study in 30 cognitively healthy and physically active older adults who underwent baseline testing and then completed two experimental visits in which they performed a mnemonic discrimination task before and after either 30 min of cycling exercise or 30 min of seated rest. Linear mixed-effects analyses were conducted in which condition order and age were controlled, time (pre vs. post) and condition (exercise vs. rest) were modeled as fixed effects, and subject as a random effect. Results: No significant time by condition interaction effect was found for object recognition (p = .254, η2 =.01), while a significant reduction in interference was found for mnemonic discrimination performance following the exercise condition (p = .012, η2 =.07). A post-intervention only analysis indicated that there was no difference between condition for object recognition (p = .186, η2 =.06), but that participants had better mnemonic discrimination performance (p < .001, η2 =.22) following the exercise. Conclusions: Our results suggest a single session of moderate-intensity aerobic exercise may reduce interference and elicit better mnemonic discrimination performance in healthy older adults, suggesting benefits for hippocampal-specific memory function.
  • Thumbnail Image
    Item
    Variability in Cognitive Performance and Learning in Younger and Older Adults Explained by Cardiovascular Fitness, Physical Activity, and APOE Genotype
    (2013) Kayes, Maureen K.; Hatfield, Bradley D; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This dissertation investigated the association of physical activity with cognition in two cross-sectional studies. Physical activity has been positively associated with cognitive function, and in older adult populations has shown an additional benefit for carriers of the ApoE- å4 allele. Cognitive training has also revealed a benefit for improved cognitive performance. Questions remain, however, about the interaction of these factors in their relation with cognition. One study addressed the relationship between physical activity and cognitive performance during executive function and working memory challenges in adults ages 50-70, and the other explored the role that physical activity plays in learning in adults ages 22-50 undergoing an online cognitive training intervention. In both studies, regard for influence of the ApoE genotype was considered, and the concept of specificity of physical activity was explored through employment of measures of both cardiovascular fitness and weekly physical activity kilocalorie expenditure. The study of older adults revealed that performance on a working-memory task was positively related to weekly kilocalorie expenditure in APOE-å4 carriers, with no such benefit for non-carriers during a moderate challenge condition of the task, while a positive relationship was revealed for both å4 carriers and non-carriers during a more challenging condition, but the magnitude of the relationship was greater in å4 carriers. The study of younger adults revealed no transfer benefits for cognitive training; however, cardiovascular fitness was positively related to performance after the intervention on a transfer task of proactive interference, and a positive trend was also found for cardiovascular fitness on a divided-attention language vocabulary learning task. No association was observed with regard to APOE-å4 genotype for any post-intervention task or learning transfer challenge. Taken together, these studies reveal that physical activity is associated with improved cognition in younger and older adults alike, but with specificity as to volume or intensity of physical activity mediating the relationship, cognitive processes benefited, and the role that the APOE-å4 genotype plays.
  • Thumbnail Image
    Item
    Examining the role of stressful life events on cognition and determining mediating and moderating pathways among postmenopausal women
    (2011) Bibeau, Wendy; Young, Deborah R; Epidemiology and Biostatistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    BACKGROUND: Major life events, largely considered to be a source of great stress, are an inevitable process of the life span. Preliminary evidence suggests that the stress arising from major life events may serve as a risk factor for cognitive function decline. Evidence also indicates external (e.g., physical activity) and internal factors (i.e., psychological variables) can attenuate the physiologic effects of stress. Thus, there may be two important pathways through which stress affects health. PURPOSE: The primary aim of this dissertation was to investigate the independent and interactive effects of stressful life events on cognitive function among a sample of postmenopausal women. In addition, the possible moderating and or mediating role of external and internal factors on the relationship between stressful life events and cognitive function were examined. METHODS: Data from the Women's Health Initiative Memory Study, a randomly selected subset of the Women's Health Initiative Hormone Trial, were analyzed. To control for any treatment effects, only data from participants randomized into the placebo groups were pooled and used for all analyses, leaving a total of 3775participants. All participants had five data collections points, including baseline through four years of follow-up. Linear mixed effects models were used to answer all prospective research questions. Moderation and mediation models were used to determine presence of effect modification or mediation of external or internal variables. RESULTS: Our results appear to indicate that there was a negative relationship between stressful life events and cognitive function scores. Reporting an ill spouse/partner was associated with lower cognition scores compared to those without reporting a spouse/partner (B = -0.68, p < 0.0001). Exposure to three or more stressful life events at every data collection period was also associated with lower cognitive function scores (B = -0.61, p = 0.021). External factors did not appear to moderate this negative relationship; however, internal factors such as optimism, hostility, and negative expressiveness did. Specifically, exposure to more stressful life events was associated with less favorable psychological states, which in turn, were associated with lower cognitive function scores. CONCLUSION: Our results appear to lend support that exposure to certain life events and repeated exposure of stressful life events is associated with lower cognitive functioning. In addition, our findings provide modest evidence that psychological mechanisms are an important pathway through which stressful life events affect cognitive functioning over time among a representative sample of post-menopausal women. While stressful life events are largely unavoidable, the associated increased risk of cognitive function decline may be in part offset by various psychological factors.