Robitaille et al., 2013. Longitudinal mediation of processing speed on age-related change in memory and fluid intelligence.

Robitaille, A., Piccinin, A. M., Muniz-Terrera, G., Hoffman, L., Johansson, B., Deeg, D. J., Aartsen, M.J., Comijs, H.C. & Hofer, S. M. (2013). Longitudinal mediation of processing speed on age-related change in memory and fluid intelligence. Psychology and aging, 28(4), 887.

Year: 
2013
Status: 
complete
Abstract: 

Age-related decline in processing speed has long been considered a key driver of cognitive aging. While the majority of empirical evidence for the processing speed hypothesis has been obtained from analyses of between-person age differences, longitudinal studies provide a direct test of within-person change. Using recent developments in longitudinal mediation analysis, we examine the speed—mediation hypothesis at both the within-and between-person levels in two longitudinal studies, Longitudinal Aging Study Amsterdam (LASA) and Origins of Variance in the Oldest-Old (OCTO-Twin). We found significant within-person indirect effects of change in age, such that increasing age was related to lower speed, which in turn relates to lower performance across repeated measures on other cognitive outcomes. Although between-person indirect effects were also significant in LASA, they were not in OCTO-Twin which is not unexpected given the age homogeneous nature of the OCTO-Twin data. A more in-depth examination through measures of effect size suggests that, for the LASA study, the within-person indirect effects were small and between-person indirect effects were consistently larger. These differing magnitudes of direct and indirect effects across levels demonstrate the importance of separating between- and within-person effects in evaluating theoretical models of age-related change. (PsycINFO Database Record (c) 2016 APA, all rights reserved)

Robitaille et al., 2012. Multivariate longitudinal modeling of cognitive aging: Examining associations among change and variation in processing speed and visuospatial ability.

Robitaille, A., Muniz-Terrera, G., Piccinin, A. M., Johansson, B., & Hofer, S. M. (2012). Multivariate longitudinal modeling of cognitive aging: Examining associations among change and variation in processing speed and visuospatial ability. GeroPsych: The Journal of Gerontopsychology and Geriatric Psychiatry, 25, 15-25.

Year: 
2012
Status: 
complete
Presentation Citations: 

Robitaille, A., Piccinin, A.M., Muniz, G., Hoffman, L., Johansson, B., Deeg, D.J., Aartsen, M.J., Comijs, H.C., & Hofer, S.M., (November, 2013). Longitudinal mediation of processing speed on age-related change in memory and fluid intelligence. Poster presented at the 66th Annual Scientific Meeting of the Gerontological Society of America, New Orleans, LA.

Robitaille, A., Muniz, G., Piccinin, A.M., Hofer, S.M. (2011, October). Multivariate longitudinal modeling of cognitive change: Relationship between processing speed and other cognitive outcomes. 40th Annual Scientific and Educational Meeting of the CAG & 4th Pan American Congress of the IAGG, Ottawa, ON.

Robitaille, A., Muniz, G., Piccinin, A.M., Hofer, S.M. (November, 2011). Does Processing Speed Account for Aging-related Change in other Cognitive Functions? In A.M. Piccinin & G. Muniz (Chairs), Advances in Understanding Cognitive Aging: Longitudinal Research on Change, Variation, and Plasticity. Symposium conducted at the 64th Annual Scientific Meeting of the Gerontological Society of America, Boston, MA

Robitaille, A., Muniz, G., Piccinin, A.M., Johansson, B.,&  Hofer, S.M. (February, 2012). Multivariate longitudinal modeling of cognitive change: Relationship between processing speed and visuospatial ability. Poster session submitted to the 2012 SRCD Themed Meeting: Developmental Methodology. Tampa, Florida

Abstract: 

We illustrate the use of the parallel latent growth curve model using data from OCTO-Twin. We found a significant intercept-intercept and slope-slope association between processing speed and visuospatial ability. Within-person correlations among the occasion-specific residuals were significant, suggesting that the occasion-specific fluctuations around individual’s trajectories, after controlling for intraindividual change, are related between both outcomes. Random and fixed effects for visuospatial ability are reduced when we include structural parameters (directional growth curve model) providing information about changes in visuospatial abilities after controlling for processing speed. We recommend this model to researchers interested in the analysis of multivariate longitudinal change, as it permits decomposition and directly interpretable estimates of association among initial levels, rates of change, and occasion-specific variation.