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

TitleProcessing speed and the relationship between Trail Making Test-B performance, cortical thinning and white matter microstructure in older adults.
Publication TypeJournal Article
Year of Publication2017
AuthorsMacPherson SE, Cox SR, Dickie DA, Karama S, Starr JM, Evans AC, Bastin ME, Wardlaw JM, Deary IJ
JournalCortex
Volume95
Pagination92-103
Date Published2017 Oct
ISSN1973-8102
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.

DOI10.1016/j.cortex.2017.07.021
Alternate JournalCortex
PubMed ID28865241
PubMed Central IDPMC5637162