title: The relationship between executive functioning, processing speed, and white matter integrity in multiple sclerosis.
abstract: The primary purpose of the current study was to examine the relationship between performance on executive tasks and white matter integrity, assessed by diffusion tensor imaging (DTI) in multiple sclerosis (MS). A second aim was to examine how processing speed affects the relationship between executive functioning and fractional anisotropy (FA). This relationship was examined in two executive tasks that rely heavily on processing speed: the Color-Word Interference Test and the Trail Making Test (Delis-Kaplan Executive Function System). It was hypothesized that reduced FA is related to poor performance on executive tasks in MS, but that this relationship would be affected by the statistical correction of processing speed from the executive tasks. A total of 15 healthy controls and 25 persons with MS participated. Regression analyses were used to examine the relationship between executive functioning and FA, both before and after processing speed was removed from the executive scores. Before processing speed was removed from the executive scores, reduced FA was associated with poor performance on the Color-Word Interference Test and Trail Making Test in a diffuse network including corpus callosum and superior longitudinal fasciculus. However, once processing speed was removed, the relationship between executive functions and FA was no longer significant on the Trail Making Test, and significantly reduced and more localized on the Color-Word Interference Test.
authors.affiliation: Neuropsychology & Neuroscience Laboratory, Kessler Foundation Research Center, West Orange, NJ 07052, USA. hgenova@kesslerfoundation.org
authors.forename: Helen M
authors.initials: HM
authors.lastname: Genova
authors.forename: John
authors.initials: J
authors.lastname: DeLuca
authors.forename: Nancy
authors.initials: N
authors.lastname: Chiaravalloti
authors.forename: Glenn
authors.initials: G
authors.lastname: Wylie
mesh_terms: D000328:Adult; D016880:Anisotropy; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D038524:Diffusion Magnetic Resonance Imaging; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D056784:Leukoencephalopathies / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D020528:Multiple Sclerosis, Chronic Progressive / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D009483:Neuropsychological Tests; D011594:Psychometrics; D011930:Reaction Time / Q000502:physiology*; D057190:Stroop Test / Q000706:statistics & numerical data; D014145:Trail Making Test / Q000706:statistics & numerical data