Brain volumetric changes and cognitive ageing during the eighth decade of life.

Stuart J Ritchie,John M Starr,Paul Redmond,Maria Del C Valdes Hernandez,Mark E Bastin,Adele M Taylor,David Alexander Dickie,Janie Corley,Ian J Deary,Alison Pattie,Benjamin S Aribisala,Natalie A Royle,Simon R Cox,Alan J Gow,Ruth Sibbett,Susana Muñoz Maniega,Joanna M Wardlaw

doi:10.1002/hbm.22959

Abstract

Later‐life changes in brain tissue volumes—decreases in the volume of healthy grey and white matter and increases in the volume of white matter hyperintensities (WMH)—are strong candidates to explain some of the variation in ageing‐related cognitive decline. We assessed fluid intelligence, memory, processing speed, and brain volumes (from structural MRI) at mean age 73 years, and at mean age 76 in a narrow‐age sample of older individuals (n = 657 with brain volumetric data at the initial wave, n = 465 at follow‐up). We used latent variable modeling to extract error‐free cognitive levels and slopes. Initial levels of cognitive ability were predictive of subsequent brain tissue volume changes. Initial brain volumes were not predictive of subsequent cognitive changes. Brain volume changes, especially increases in WMH, were associated with declines in each of the cognitive abilities. All statistically significant results were modest in size (absolute r‐values ranged from 0.114 to 0.334). These results build a comprehensive picture of macrostructural brain volume changes and declines in important cognitive faculties during the eighth decade of life. Hum Brain Mapp 36:4910–4925, 2015. © 2015 The Authors. Human Brain Mapping Published by Wiley Periodicals, Inc

Highlights

Several important cognitive abilities decline with age, even in the absence of dementia or other pathologies [Hedden and Gabrieli, 2004; Tucker-Drob, 2009]
In a two-wave longitudinal study with a large narrow-age cohort, we investigate the associations between changes in important domains of cognitive ability and in total brain volume, grey matter volume, normal-appearing white matter volume, and volume of white matter hyperintensity (WMH) during the eighth decade of life
As has already been reported in this dataset [Royle et al, 2013; Valdes Hernandez et al, 2013], each of the brain volume measures was significantly correlated with each of the cognitive abilities at age 73: total, grey, and white matter volumes had positive correlations with cognitive ability, whereas WMH volume correlated negatively with all three cognitive factors. This pattern was replicated in the new data from age 76: positive correlations with cognitive ability were found for total, grey, and white matter volumes, and negative correlations were found for WMH volume

Summary

Introduction

Several important cognitive abilities decline with age, even in the absence of dementia or other pathologies [Hedden and Gabrieli, 2004; Tucker-Drob, 2009]. Measures of total brain volume, as well as the volumes of specific tissue types, have consistently been shown to correlate with cognitive ability level throughout adulthood [Arvanitakis et al, in press; Grazioplene et al, 2015; Pietschnig et al, 2014], and changes in brain tissue volumes accompany normal ageing, with healthy tissue volumes declining and white matter hyperintensity (WMH) volumes increasing [Fjell and Walhovd, 2010; Fleischman et al, 2014; Prins and Scheltens, 2015]. In a two-wave longitudinal study with a large narrow-age cohort, we investigate the associations between changes in important domains of cognitive ability and in total brain volume, grey matter volume, normal-appearing white matter volume, and volume of WMH during the eighth decade of life

Methods

Results

Discussion

Conclusion