Processing speed and the relationship between Trail Making Test-B performance, cortical thinning and white matter microstructure in older adults

MacPherson, S. E., Cox, S. R., Dickie, D. A. , Karama, S., Starr, J. M., Evans, A. C., Bastin, M. E., Wardlaw, J. M. and Deary, I. J. (2017) Processing speed and the relationship between Trail Making Test-B performance, cortical thinning and white matter microstructure in older adults. Cortex, 95, pp. 92-103. (doi: 10.1016/j.cortex.2017.07.021) (PMID:28865241) (PMCID:PMC5637162)

Abstract

Part B of the Trail Making Test (TMT-B) is widely used as a quick and easy to administer measure of executive dysfunction. The current study investigated the relationships between TMT-B performance, brain volumes, cortical thickness and white matter water diffusion characteristics in a large sample of older participants, before and after controlling for processing speed. Four hundred and eleven healthy, community-dwelling older adults who were all born in 1936 were assessed on TMT-B, 5 tests of processing speed, and provided contemporaneous structural and diffusion MRI data. Significant relationships were found between slower TMT-B completion times and thinner cortex in the frontal, temporal and inferior parietal regions as well as the Sylvian fissure/insula. Slower TMT-B completion time was also significantly associated with poorer white matter microstructure of the left anterior thalamic radiation, and the right uncinate fasciculus. The majority of these associations were markedly attenuated when additionally controlling for processing speed. These data suggest that individual differences in processing speed contribute to the associations between TMT-B completion time and the grey and white matter structure of older adults.

• Item Type: Articles
• Additional Information: This research and LBC1936 phenotype collection were supported by Research into Ageing and continues as part of The Disconnected Mind project (http://www.disconnectedmind.ed.ac.uk), funded by Age UK, with additional funding from the UK Medical Research Council under grant numbers G0701120, G1001245 and MR/M013111/1. MRI acquisition and analyses were conducted at the Brain Research Imaging Centre, Neuroimaging Sciences, University of Edinburgh (www.bric.ed.ac.uk) which is part of SINAPSE (Scottish Imaging Network—A Platform for Scientific Excellence) collaboration (www.sinapse.ac.uk) funded by the Scottish Funding Council and the Chief Scientist Office. This work was undertaken within The University of Edinburgh Centre for Cognitive Ageing and Cognitive Epidemiology (www.ccace.ed.ac.uk), part of the cross council Lifelong Health and Wellbeing Initiative (MR/K026992/1), for which funding from the BBSRC and MRC is gratefully acknowledged. The cortical thickness analysis was funded by a Scottish Funding Council PECRE grant to SINAPSE (DAD).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Dickie, Dr David Alexander
• Authors: MacPherson, S. E., Cox, S. R., Dickie, D. A., Karama, S., Starr, J. M., Evans, A. C., Bastin, M. E., Wardlaw, J. M., and Deary, I. J.
• College/School: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Journal Name: Cortex
• Publisher: Elsevier
• ISSN: 0010-9452
• ISSN (Online): 1973-8102
• Published Online: 09 August 2017
• Copyright Holders: Copyright © 2017 The Authors
• First Published: First published in Cortex 95:92-103
• Publisher Policy: Reproduced under a Creative Commons License