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Lookup NU author(s): Dr Tom Owen, Professor Yujiang WangORCiD, Professor Peter TaylorORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2020 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd. Previous studies investigating associations between white matter alterations and duration of temporal lobe epilepsy (TLE) have shown differing results, and were typically limited to univariate analyses of tracts in isolation. In this study, we apply a multivariate measure (the Mahalanobis distance), which captures the distinct ways white matter may differ in individual patients, and relate this to epilepsy duration. Diffusion MRI, from a cohort of 94 subjects (28 healthy controls, 33 left-TLE and 33 right-TLE), was used to assess the association between tract fractional anisotropy (FA) and epilepsy duration. Using ten white matter tracts, we analysed associations using the traditional univariate analysis (z-scores) and a complementary multivariate approach (Mahalanobis distance), incorporating multiple white matter tracts into a single unified analysis. For patients with right-TLE, FA was not significantly associated with epilepsy duration for any tract studied in isolation. For patients with left-TLE, the FA of two limbic tracts (ipsilateral fornix, contralateral cingulum gyrus) were significantly negatively associated with epilepsy duration (Bonferonni corrected p <.05). Using a multivariate approach we found significant ipsilateral positive associations with duration in both left, and right-TLE cohorts (left-TLE: Spearman's ρ = 0.487, right-TLE: Spearman's ρ = 0.422). Extrapolating our multivariate results to duration equals zero (i.e., at onset) we found no significant difference between patients and controls. Associations using the multivariate approach were more robust than univariate methods. The multivariate Mahalanobis distance measure provides non-overlapping and more robust results than traditional univariate analyses. Future studies should consider adopting both frameworks into their analysis in order to ascertain a more complete understanding of epilepsy progression, regardless of laterality.
Author(s): Owen TW, de Tisi J, Vos SB, Winston GP, Duncan JS, Wang Y, Taylor PN
Publication type: Article
Publication status: Published
Journal: European Journal of Neuroscience
Year: 2021
Volume: 53
Issue: 8
Pages: 2788-2803
Print publication date: 01/04/2021
Online publication date: 22/11/2020
Acceptance date: 15/11/2020
Date deposited: 26/07/2021
ISSN (print): 0953-816X
ISSN (electronic): 1460-9568
Publisher: John Wiley & Sons Ltd
URL: https://doi.org/10.1111/ejn.15055
DOI: 10.1111/ejn.15055
PubMed id: 33222308
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