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A meta‐analysis of white matter changes in temporal lobe epilepsy as studied with diffusion tensor imaging
Author(s) -
Otte Willem M.,
van Eijsden Pieter,
Sander Josemir W.,
Duncan John S.,
Dijkhuizen Rick M.,
Braun Kees P. J.
Publication year - 2012
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/j.1528-1167.2012.03426.x
Subject(s) - white matter , fractional anisotropy , diffusion mri , temporal lobe , epilepsy , psychology , frontal lobe , neuroscience , medicine , magnetic resonance imaging , radiology
Summary Purpose: Diffusion tensor imaging (DTI) is used increasingly to study white matter integrity in people with temporal lobe epilepsy (TLE). Most studies report fractional anisotropy (FA) decrease and mean diffusivity (MD) increase in multiple white matter regions. The disturbance of white matter integrity varies across studies and between regions. We aimed to obtain a more consistent estimate of white matter diffusion characteristics and relate these to the distance from the seizure focus. Methods: Studies comparing diffusion characteristics of people with epilepsy with those of healthy controls were systematically reviewed and quantified using random and mixed effects meta analysis. In addition to the overall meta‐analysis, pooled FA and MD differences were determined per hemisphere and white matter category separately. Key Findings: We included 13 cross‐sectional studies. The pooled FA difference for all white matter was −0.026 (95% confidence interval [CI] −0.033 to −0.019) and MD difference was 0.028 × 10 −3 mm 2 /s (95% CI 0.015–0.04). FA was reduced significantly in people with TLE compared with healthy controls in both ipsilateral (mean difference −0.03) and contralateral white matter (−0.02). MD was significantly increased ipsilaterally and contralaterally. MD differed significantly between white matter connected to the affected temporal lobe and remote white matter. Significance: The meta‐analysis provides a better estimation of the true diffusion characteristics. White matter structural integrity in TLE is disturbed more severely in the ipsilateral than in the contralateral hemisphere, and tracts closely connected with the affected temporal lobe are most disturbed. The exact underlying mechanisms remain to be elucidated.