Hofer, 2013. On the robustness of results from longitudinal observational studies: Integrative data analysis and designs for optimizing detection of within-person change.

Year: 
2013
Status: 
complete
Presentation Citations: 

Hofer, S. M. (October, 2013). On the robustness of results from longitudinal observational studies: Integrative data analysis and designs for optimizing detection of within-person change. Paper presented at the annual meeting of the Society of Multivariate Experimental Psychology, St. Pete Beach, FL.

Hofer et al., 2009. Patterns of between-person age differences and within-person changes in cognitive capabilities with age

Year: 
2009
Status: 
complete
Presentation Citations: 

Hofer, S. M., Piccinin, A. M., Bontempo, D. E., Sparks, C., & Hoffman, L. (2009, November). Integrative Analysis of Longitudinal Studies of Aging (IALSA): Patterns of between-person age differences and within-person changes in cognitive capabilities with age.  In S. M. Hofer (Chair), Coordinated and pooled data analyses of longitudinal studies of aging: Aging and dementia-related change in cognition, affect, and physical functioning. Paper symposium conducted at the annual meeting of the Gerontological Society of America, Atlanta.

Wray et al., 2010. Diabetes and cognition in midlife and older adulthood.

Year: 
2010
Status: 
complete
Presentation Citations: 

Wray, L., Alwin, D. F., Hofer, S. M., Zeisser, K. L., Chu, C-J. (2010, August). Diabetes and cognition in midlife and older adulthood.  Paper presented at the annual meeting of the American Sociological Association, Atlanta.

Wray, L., Alwin, D. F., Hofer, S. M., Zeisser, K. L., Chu, C-J. (2010, November). Diabetes and cognitive change in midlife and older adulthood.  Poster presented at the annual meeting of the Gerontological Society of America, New Orleans.

Cadar et al., 2016. The role of cognitive reserve on terminal decline: a cross-cohort analysis from two European studies

Cadar, D., Stephan, B. C., Jagger, C., Johansson, B., Hofer, S. M., Piccinin, A. M., & Muniz‐Terrera, G. (2016). The role of cognitive reserve on terminal decline: A cross‐cohort analysis from two European studies: OCTO‐Twin, Sweden, and Newcastle 85+, UK. International Journal of Geriatric Psychiatry, 31(6), 601-610.

Year: 
2017
Status: 
complete
Abstract: 

OBJECTIVE: Cognitive performance shows a marked deterioration in close proximity to death, as postulated by the terminal decline hypothesis. The effect of education on the rate of terminal decline in the oldest people (i.e. persons 85+ years) has been controversial and not entirely understood. In the current study, we investigated the rate of decline prior to death with a special focus on the role of education and socioeconomic position, in two European longitudinal studies of ageing: the Origins of Variance in the Old-Old: Octogenarian Twins (OCTO-Twin) and the Newcastle 85+ study.

METHODS: A process-based approach was used in which individuals' cognitive scores were aligned according to distance to death. In a coordinated analysis, multilevel models were employed to examine associations between different markers of cognitive reserve (education and socioeconomic position) and terminal decline using the mini-mental state examination (MMSE), controlling for age at baseline, sex, dementia incidence and time to death from the study entry to the time of death within each cohort.

RESULTS: The current findings suggest that education was positively associated with higher MMSE scores prior to death in the OCTO-Twin, but not in the Newcastle 85+ study, independent of socioeconomic position and other factors such as baseline age, sex and time to death from the study entry. However, education was not associated with the rate of terminal decline in both of these studies.

CONCLUSIONS: Our results offer only partial support to the cognitive reserve hypothesis and cognitive performance prior to death.

Yoneda, in progress. Blood Pressure Variability and Cognitive Functioning: A Systematic Review and Meta-Analysis

Status: 
in progress
Abstract: 

Introduction: Several studies indicate that blood pressure variability (BPV) is negatively related to cognitive functioning at the interindividual level, as well as cognitive decline at the intraindividual level. However, a small number of studies report a positive relationship between BPV and cognitive functioning in individuals at high risk of cardiovascular disease. Study features in this field vary considerably, including differences in the health of the participants that are targeted, the number of assessments that are included to calculate variability, the timing between assessments, the way in which variability is calculated, the position of participants during measurement, and the assessment of cognition. The objective of this project is to critically analyze the outcome of research reporting the association between blood pressure variability and cognitive functioning or cognitive status in order to understand which (if any) study characteristics may be contributing to inconsistencies in the field. Data Sources: PsycInfo and Web of Science without language restrictions, including papers published in any year, as well as forward and backward searches of reference lists of included articles and relevant reviews for additional reports.

Methods: Study justification, search strategy, and methodological approach for this research synthesis are documented and pre-registered through the Open Science Framework (OSF), which is publically available for readers (https://osf.io/vmnuq/). PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses; Moher et al., 2009) was used to create the protocol for this systematic review and meta-analysis. Multi-level meta-analysis with random effects and maximum likelihood variance estimation will be applied to examine the cumulative evidence for the association between BPV and cognitive functioning.

Results: In Progress

Discussion: In Progress

Robitaille, 2014. Physical Activity And Cognitive Functioning in the Oldest Old

Robitaille, A., Muniz, G., Lindwall, M., Piccinin, A. M., Hoffman, L., Johansson, B., & Hofer, S. M. (2014). Physical activity and cognitive functioning in the oldest old: within-and between-person cognitive activity and psychosocial mediators. European Journal of Ageing, 11(4), 333-347.

Year: 
2012
Status: 
complete
Presentation Citations: 

Robitaille, A., Muniz, G., Lindwall, M., Piccinin, A.M., Hoffman, L., Johansson, B., & Hofer, S.M. (October, 2012). Physical activity and cognitive functioning among older adults: Within- and between-person cognitive and psychosocial mediators.  Poster session presented at the 41th Annual Scientific and Educational Meeting of the CAG, Vancouver, BC.

Abstract: 

The current study examines the role of social contact intensity, cognitive activity, and depressive symptoms as within- and between-person mediators for the relationships between physical activity and cognitive functioning. All three types of mediators were considered simultaneously using multilevel structural equations modeling with longitudinal data. The sample consisted of 470 adults ranging from 79.37 to 97.92 years of age (M = 83.4; SD = 3.2) at the first occasion. Between-person differences in cognitive activity mediated the relationship between physical activity and cognitive functioning, such that individuals who participated in more physical activities, on average, engaged in more cognitive activities and, in turn, showed better cognitive functioning. Mediation of between-person associations between physical activity and memory through social contact intensity was also significant. At the within-person level, only cognitive activity mediated the relationship between physical activity and change in cognition; however, the indirect effect was small. Depressive symptomatology was not found to significantly mediate within- or between-person effects on cognitive change. Our findings highlight the implications of physical activity participation for the prevention of cognitive decline and the importance of meditational processes at the between-person level. Physical activity can provide older adults with an avenue to make new friendships and engage in more cognitive activities which, in turn, attenuates cognitive decline.

 

Rast & Hofer, 2014. Longitudinal design considerations to optimize power to detect variances and covariances among rates of change: Simulation results based on actual longitudinal studies

Rast, P., & Hofer, S. M. (2014). Longitudinal design considerations to optimize power to detect variances and covariances among rates of change: Simulation results based on actual longitudinal studies. Psychological Methods, 19(1), 133.

Year: 
2012
Status: 
complete
Presentation Citations: 

Hofer, S. M., & Rast, P. (October, 2012). Substantial power to detect variance and covariance among rates of change: Results based on actual longitudinal studies and related simulations. Paper presented at the annual meeting of the Society of Multivariate Experimental Psychology, Vancouver, BC

Abstract: 

We investigated the power to detect variances and covariances in rates of change in the context of existing longitudinal studies using linear bivariate growth curve models. Power was estimated by means of Monte Carlo simulations. Our findings show that typical longitudinal study designs have substantial power to detect both variances and covariances among rates of change in a variety of cognitive, physical functioning, and mental health outcomes. We performed simulations to investigate the interplay among number and spacing of occasions, total duration of the study, effect size, and error variance on power and required sample size. The relation between growth rate reliability (GRR) and effect size to the sample size required to detect power ≥ .80 was non-linear, with rapidly decreasing sample sizes needed as GRR increases. The results presented here stand in contrast to previous simulation results and recommendations (Hertzog, Lindenberger, Ghisletta, & von Oertzen, 2006Hertzog, von Oertzen, Ghisletta, & Lindenberger, 2008von Oertzen, Ghisletta, & Lindenberger, 2010), which are limited due to confounds between study length and number of waves, error variance with GCR, and parameter values which are largely out of bounds of actual study values. Power to detect change is generally low in the early phases (i.e. first years) of longitudinal studies but can substantially increase if the design is optimized. We recommend additional assessments, including embedded intensive measurement designs, to improve power in the early phases of long-term longitudinal studies.

Alwin & Hofer, 2011. Health and Cognition in Aging Research

Alwin, D. F., & Hofer, S. M. (2011). Health and cognition in aging research. Journals of Gerontology: Psychological Sciences, 66B(s1), i9-i16.

Year: 
2011
Status: 
complete
Abstract: 

This supplemental issue of The Journals of Gerontology, Series B: Psychological Sciences and Social Sciences is based on papers presented at a conference on “Cognition, Health, and Aging: Integrating Perspectives across Disciplines” held at Pennsylvania State University, October 30– 31, 2009. This conference focused on discussing new research findings and methodological approaches regarding the interplay of the dynamics of biological factors in cognitive and related outcomes and associated physiological changes that are linked to cognitive aging, including sensory and disease-related changes. We attracted an outstanding group of researchers doing work in these areas, across several disciplines—biology, epidemiology, demography, developmental psychology, gerontology, neuropsychology, and sociology—to consider how best to measure these processes and model relevant data in ways that sort out aggregate population trends and individual-level age-related changes in health and cognitive functioning.

In the following, we summarize the key contributions of the papers presented at the conference, many of which are published in the present supplementary issue.

Muniz-Terrera et al., 2011. Joint Modeling of Longitudinal Change and Survival

Muniz-Terrera, G., Piccinin, A. M., Johansson, B., Matthews, F., & Hofer, S. M. (2011). Joint modeling of longitudinal change and survival: An investigation of the association between change in memory scores and death. GeroPsych: The Journal of Gerontopsychology and Geriatric Psychiatry, 24(4), 177-185.

Year: 
2011
Status: 
complete
Abstract: 

Joint longitudinal-survival models are useful when repeated measures and event time data are available and possibly associated. The application of this joint model in aging research is relatively rare, albeit particularly useful, when there is the potential for nonrandom dropout. In this article we illustrate the method and discuss some issues that may arise when fitting joint models of this type. Using prose recall scores from the Swedish OCTO-Twin Longitudinal Study of Aging, we fitted a joint longitudinal-survival model to investigate the association between risk of mortality and individual differences in rates of change in memory. A model describing change in memory scores as following an accelerating decline trajectory and a Weibull survival model was identified as the best fitting. This model adjusted for random effects representing individual variation in initial memory performance and change in rate of decline as linking terms between the longitudinal and survival models. Memory performance and change in rate of memory decline were significant predictors of proximity to death. Joint longitudinal-survival models permit researchers to gain a better understanding of the association between change functions and risk of particular events, such as disease diagnosis or death. Careful consideration of computational issues may be required because of the complexities of joint modeling methodologies.

Van den Kommer et al., 2010. Classification models for early identification of persons at risk for dementia in primary care: An evaluation in a sample aged 80 years and older

Van den Kommer, T. N., Bontempo, D. E., Comijs, H. C., Hofer, S. M., Dik, M. G., Piccinin, A. M., Jonker, C., Deeg, D. J. H., & Johansson, B. (2010). Classification models for early identification of persons at risk for dementia in primary care: An evaluation in a sample aged 80 years and older, Dementia and Geriatric Cognitive Disorders, 28(6), 567-577.

Year: 
2010
Status: 
complete
Abstract: 

Aim: To evaluate previously developed classification models to make implementation in primary care possible and aid early identification of persons at risk for dementia. Methods: Data were drawn from the OCTO-Twin study. At baseline, 521 persons ≧80 years of age were nondemented, and for 387 a blood sample was available. Predictors of dementia were collected and analyzed in initially nondemented persons using generalized estimating equations and Cox survival analyses. Results: In the basic model using predictors already known or easily obtained (basic set), the mean 2-year predictive value increased from 6.9 to 28.8% in persons with memory complaints and an MMSE score ≤25. In the extended model, using both the basic set and an extended set of predictors requiring further assessment, the 8-year predictive value increased from 15.0 to 45.8% in persons with low cholesterol and an MMSE score ≤24. Conclusion: Both models can contribute to an improved early identification of persons at risk for dementia in primary care.

Pages