Heterogeneous Indicators of Cognitive Performance and Performance Variability Across the Lifespan.

Lauren A Rutter,Ipsit V Vahia,Brent P Forester,Laura Germine,Kerry J Ressler

doi:10.3389/fnagi.2020.00062

Abstract

Reaction time (RT) and RT variability are core components of cognitive performance that can be captured through brief and easy-to-administer tasks of simple RT and choice RT. The current study aims to describe age-related differences in cognitive performance, toward better characterizing normative performance across the lifespan. We examined mean and variability of response times on a simple RT and choice RT tasks in a large and diverse web-based sample (10,060 visitors to TestMyBrain.org). We also examined lifespan-related differences in response time variability using multiple different approaches (raw variability, mean scaled variability, and mean residualized variability). These analyses revealed significant heterogeneity in the patterns of age-related differences in performance, across metrics and within different estimates of the same metric. Based on segmented regression analysis, age of peak performance differed significantly across metrics, with young adults having the best performance based on measures of median RT, middle age adults at peak on certain measures of RT variability (standard deviation and coefficient of variability), and older adults showing the best performance based on accuracy and mean-corrected RT variability. Our results indicate that no single measure of cognitive performance and performance variability produces the same findings with respect to age related change, with further work needed to establish the validity of particular metrics for different applications.

Highlights

Performance variability has been linked with cognitive decline (e.g., Hultsch et al, 2000, 2008; Williams et al, 2005; Haynes et al, 2018)
In a systematic review and metaanalysis, Dykiert et al (2012) found that effect sizes were larger for variability measures that did not adjust for differences in mean reaction time (RT) than those that did, with some studies that used meanadjusted RT variability metrics showing little to no increase in RT variability in older age
Our study expands on the prior literature, as it is the largest evaluation of RT variability in measures of choice (Choice RT) and simple RT (Simple RT) across the lifespan to date

Summary

INTRODUCTION

Performance variability has been linked with cognitive decline (e.g., Hultsch et al, 2000, 2008; Williams et al, 2005; Haynes et al, 2018). In a systematic review and metaanalysis, Dykiert et al (2012) found that effect sizes were larger for variability measures that did not adjust for differences in mean RT than those that did, with some studies that used meanadjusted RT variability metrics showing little to no increase in RT variability in older age. We focus on variability in RTs within a task, rather than variability across trials within the same session (dispersion) or variability in scores at different timepoints (e.g., longitudinal variability, measurement burst designs, or ecological momentary assessment) While the latter forms of variability are potentially important and informative (e.g., Bielak et al, 2010; Stawski et al, 2019), they are related to fluctuations along longer time scales (hours, days, years) rather than the moment-to-moment variability we focus on for the purposes of this study. Our study expands on the prior literature, as it is the largest evaluation of RT variability in measures of choice (Choice RT) and simple RT (Simple RT) across the lifespan to date

Participants

RESULTS

DISCUSSION

Findings

ETHICS STATEMENT