Lookup NU author(s): Professor Fiona Matthews
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
This study examines variability across the age span in cognitive performance in a cross-sectional, population-based, adult lifespan cohort from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) study (n = 2680). A key question we highlight is whether using measures that are designed to detect age-related cognitive pathology may not be sensitive to, or reflective of, individual variability among younger adults. We present three issues that contribute to the debate for and against age-related increases in variability. Firstly, the need to formally define measures of central tendency and measures of variability. Secondly, in addition to the commonly addressed location-confounding (adjusting for covariates) there may exist changes in measures of variability due to confounder sub-groups. Finally, that increases in spread may be a result of floor or ceiling effects; where the measure is not sensitive enough at all ages. From the Cam-CAN study, a large population-based dataset, we demonstrate the existence of variability-confounding for the immediate episodic memory task; and show that increasing variance with age in our general cognitive measures is driven by a ceiling effect in younger age groups.
Author(s): Green E, Shafto MA, Matthews FE, Cam-CAN, White SR
Publication type: Article
Publication status: Published
Journal: International Journal of Environmental Research and Public Health
Print publication date: 01/12/2015
Online publication date: 07/12/2015
Acceptance date: 01/12/2015
ISSN (print): 1661-7827
ISSN (electronic): 1660-4601
Publisher: MDPI AG
PubMed id: 26690191
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