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Search Results: 1 - 10 of 170058 matches for " Robert F. Kennison "
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Social Activity and Cognitive Functioning Over Time: A Coordinated Analysis of Four Longitudinal Studies
Cassandra L. Brown,Laura E. Gibbons,Robert F. Kennison,Annie Robitaille,Magnus Lindwall,Meghan B. Mitchell,Steven D. Shirk,Alireza Atri,Cynthia R. Cimino,Andreana Benitez,Stuart W. S. MacDonald,Elizabeth M. Zelinski,Sherry L. Willis,K. Warner Schaie,Boo Johansson,Roger A. Dixon,Dan M. Mungas,Scott M. Hofer,Andrea M. Piccinin
Journal of Aging Research , 2012, DOI: 10.1155/2012/287438
Abstract: Social activity is typically viewed as part of an engaged lifestyle that may help mitigate the deleterious effects of advanced age on cognitive function. As such, social activity has been examined in relation to cognitive abilities later in life. However, longitudinal evidence for this hypothesis thus far remains inconclusive. The current study sought to clarify the relationship between social activity and cognitive function over time using a coordinated data analysis approach across four longitudinal studies. A series of multilevel growth models with social activity included as a covariate is presented. Four domains of cognitive function were assessed: reasoning, memory, fluency, and semantic knowledge. Results suggest that baseline social activity is related to some, but not all, cognitive functions. Baseline social activity levels failed to predict rate of decline in most cognitive abilities. Changes in social activity were not consistently associated with cognitive functioning. Our findings do not provide consistent evidence that changes in social activity correspond to immediate benefits in cognitive functioning, except perhaps for verbal fluency. 1. Introduction Cognitive decline in older adulthood remains an area of great concern as the population ages. Some changes in cognitive function, such as decreased processing speed, are considered normative aspects of the aging process [1]. However, the impact of even mild cognitive impairment on functional capacity highlights the importance of maintaining cognitive function for as long as possible [2]. Substantial evidence suggests that lifestyle factors and cognitive function in older adulthood are related [3]. Sometimes summarized by the adage “use it or lose it,” current evidence suggests that leading an active lifestyle “using it” may buffer the effects of age-related cognitive decline “losing it” [3–5]. The mechanisms by which an active and engaged lifestyle may be related to better or preserved cognitive function in older adulthood remain to be fully elucidated. However, the cognitive reserve hypothesis predicts that some individuals are better able to withstand the physiological insults to the brain without measurable cognitive deficits because they had greater capacity to begin with [6]. Individuals may be able to actively increase their “reserve” through engaging in cognitively stimulating activities [3]. Social activities are considered part of what constitutes an active and engaged lifestyle, alongside cognitive and physical activities [3, 4, 7–9]. However, the evidence for a relationship
Cognitively Stimulating Activities: Effects on Cognition across Four Studies with up to 21 Years of Longitudinal Data
Meghan B. Mitchell,Cynthia R. Cimino,Andreana Benitez,Cassandra L. Brown,Laura E. Gibbons,Robert F. Kennison,Steven D. Shirk,Alireza Atri,Annie Robitaille,Stuart W. S. MacDonald,Magnus Lindwall,Elizabeth M. Zelinski,Sherry L. Willis,K. Warner Schaie,Boo Johansson,Roger A. Dixon,Dan M. Mungas,Scott M. Hofer,Andrea M. Piccinin
Journal of Aging Research , 2012, DOI: 10.1155/2012/461592
Abstract: Engagement in cognitively stimulating activities has been considered to maintain or strengthen cognitive skills, thereby minimizing age-related cognitive decline. While the idea that there may be a modifiable behavior that could lower risk for cognitive decline is appealing and potentially empowering for older adults, research findings have not consistently supported the beneficial effects of engaging in cognitively stimulating tasks. Using observational studies of naturalistic cognitive activities, we report a series of mixed effects models that include baseline and change in cognitive activity predicting cognitive outcomes over up to 21 years in four longitudinal studies of aging. Consistent evidence was found for cross-sectional relationships between level of cognitive activity and cognitive test performance. Baseline activity at an earlier age did not, however, predict rate of decline later in life, thus not supporting the concept that engaging in cognitive activity at an earlier point in time increases one's ability to mitigate future age-related cognitive decline. In contrast, change in activity was associated with relative change in cognitive performance. Results therefore suggest that change in cognitive activity from one's previous level has at least a transitory association with cognitive performance measured at the same point in time. 1. Introduction With the rising proportion of older adults and increases in life expectancy [1], there has been increased interest in maintaining and promoting cognitive health in later life. Although declines in some domains of cognition are part of the natural course of aging [2, 3], sufficient evidence from prospective and observational studies indicates that the trajectories and outcomes of cognitive decline may be mitigated by participating in cognitively stimulating activities [4, 5]. Recent reviews of cognitive interventions suggest some potential benefits that may improve functioning in healthy older adults or slow decline in individuals with mild cognitive impairment (MCI) and those already affected with dementia [6–9]. Results from a meta-analysis of randomized controlled trials in healthy aging revealed a strong positive effect on cognition at immediate, medium-, and long-term followup after cognitive training [10]. Compelling results from large longitudinal studies have also shown that engagement in everyday cognitive activities predicts preserved cognition [11, 12] and decreases in incident Alzheimer’s disease [13]. It is therefore not surprising that the market for “brain fitness” technologies,
Dynamic Associations of Change in Physical Activity and Change in Cognitive Function: Coordinated Analyses of Four Longitudinal Studies
Magnus Lindwall,Cynthia R. Cimino,Laura E. Gibbons,Meghan B. Mitchell,Andreana Benitez,Cassandra L. Brown,Robert F. Kennison,Steven D. Shirk,Alireza Atri,Annie Robitaille,Stuart W. S. MacDonald,Elizabeth M. Zelinski,Sherry L. Willis,K. Warner Schaie,Boo Johansson,Marcus Praetorius,Roger A. Dixon,Dan M. Mungas,Scott M. Hofer,Andrea M. Piccinin
Journal of Aging Research , 2012, DOI: 10.1155/2012/493598
Abstract: The present study used a coordinated analyses approach to examine the association of physical activity and cognitive change in four longitudinal studies. A series of multilevel growth models with physical activity included both as a fixed (between-person) and time-varying (within-person) predictor of four domains of cognitive function (reasoning, memory, fluency, and semantic knowledge) was used. Baseline physical activity predicted fluency, reasoning and memory in two studies. However, there was a consistent pattern of positive relationships between time-specific changes in physical activity and time-specific changes in cognition, controlling for expected linear trajectories over time, across all four studies. This pattern was most evident for the domains of reasoning and fluency. 1. Introduction Previous research has clearly demonstrated that cognitive change in old age does not occur in a homogenous manner for all individuals [1–3]. A number of predictors of cognitive change in old age have been identified, such as education, hypertension, objective indices of health and cardiovascular disease, and apolipoprotein E [4]. Regular engagement in different types of activities may also influence cognitive change. More specifically, according to the “use it or lose it” hypothesis [5], regular engagement in different activities may buffer age-related decline in cognitive functioning. A number of studies have found that general lifestyle activity engagement (often operationalized as the combination of intellectual, social, and physical activities) is associated with cognitive change [6–8] and that decline in activity in older age is associated with decline in cognitive functioning. In addition to general activity, other studies have specifically targeted the association of physical activity with cognitive change. Indeed, a growing body of the literature highlights the potential benefits of physical activity on the structure and function of the brain [9, 10]. The first line of evidence for the relationship between physical activity and cognition comes from a number of cross-sectional studies demonstrating that physically active older adults have higher cognitive performance and functioning compared with less active older adults [11, 12]. However, the evidence derived from these cross-sectional studies is limited, as it is not. possible to draw conclusions in terms of more complex associations of change. Stronger evidence may be found in longitudinal studies. Longitudinal studies may be viewed as the second line of evidence, offering valuable information on the
Anisotropic spin fluctuations and superconductivity in "115'' heavy fermion compounds: 59Co NMR study in PuCoGa5
S. -H. Baek,H. Sakai,E. D. Bauer,J. N. Mitchell,J. A. Kennison,F. Ronning,J. D. Thompson
Physics , 2010, DOI: 10.1103/PhysRevLett.105.217002
Abstract: We report results of $^{59}$Co nuclear magnetic resonance measurements on a single crystal of superconducting PuCoGa5 in its normal state. The nuclear spin-lattice relaxation rates and the Knight shifts as a function of temperature reveal an anisotropy of spin fluctuations with finite wave vector q. By comparison with the isostructural members, we conclude that antiferromagnetic XY-type anisotropy of spin fluctuations plays an important role in mediating superconductivity in these heavy fermion materials.
Who Pays for Open Access?
Helen Doyle,Andy Gass,Rebecca Kennison
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0020105
Open Access and Scientific Societies
Helen Doyle,Andy Gass,Rebecca Kennison
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0020156
Whose Copy? Whose Rights?
Andy Gass,Helen Doyle,Rebecca Kennison
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0020228
The What and Whys of DOIs
Susanne DeRisi,Rebecca Kennison,Nick Twyman
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0000057
Molecular Genetic Analyses of Polytene Chromosome Region 72A-D in Drosophila melanogaster Reveal a Gene Desert in 72D
Monica T. Cooper, James A. Kennison
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023509
Abstract: We have investigated a region of ~310 kb of genomic DNA within polytene chromosome subdivisions 72A to 72D of Drosophila melanogaster. This region includes 57 predicted protein-coding genes. Seventeen of these genes are in six clusters that appear to have arisen by tandem duplication. Within this region we found 23 complementation groups that are essential for zygotic viability, and we have identified the transcription units for 18 of the 23. We also found a 55 kb region in 72D that is nonessential. Flies deficient for this region are viable and fertile. Within this nonessential region are 48 DNA sequences of 12 to 33 base pairs that are completely conserved among 12 distantly related Drosophila species. These sequences do not have the evolutionary signature of conserved protein-coding DNA sequences, nor do they appear to encode microRNAs, however, the strong selection suggests functions in wild populations that are not apparent in laboratory cultures. This region resembles dispensable gene deserts previously characterized in the mouse genome.
Open Access and Scientific Societies
Helen Doyle,Andy Gass,Rebecca Kennison
PLOS Biology , 2004, DOI: 10.1371/journal.pbio.0020156
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