title: The impact of region-specific leukoaraiosis on working memory deficits in dementia.
abstract: MRI leukoaraiosis (LA) is less likely to interfere with simple compared to more complex working memory (WM) skills. We hypothesize that LA within the left hemisphere negatively impacts higher-level WM processes in dementia. Participants with dementia (n=64; MMSE=22.0+/-3.4) performed a Backward Digit Task measuring simple storage/rehearsal (ANY-ORDER) and complex disengagement/temporal re-ordering (SERIAL-ORDER) recall. A visual rating scale categorized MRI-LA in five regions per hemisphere: frontal and parietal centrum semiovale, white matter around the frontal horns, body of the lateral ventricles and posterior horns. Amidst equivalent hemispheric LA scores [t(62)=-1.12, p>0.05], correlations revealed an association between left-sided LA and SERIAL-ORDER recall (r=-0.31, p=0.007) with LA around the posterior horn (rho=-0.30, p=0.008) and frontal centrum semiovale (rho=-0.29, p=0.01) showing the greatest association. Regression modeling confirmed the left posterior horn contribution to SERIAL-ORDER performance variance. Results suggest involvement of anterior (fronto-striatal) and more posterior (inferior parietal) white matter tracts in higher order WM deficits in dementia.
authors.affiliation: MRC Center for Neurodegeneration, Department of Psychology-Section of Brain Maturation, Institute of Psychiatry, King's College London, M6.01, P050 De Crespigny Park, London SE5 8AH, United Kingdom. m.lamar@iop.kcl.ac.uk
authors.forename: Melissa
authors.initials: M
authors.lastname: Lamar
authors.forename: Marco
authors.initials: M
authors.lastname: Catani
authors.forename: Catherine C
authors.initials: CC
authors.lastname: Price
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Heilman
authors.forename: David J
authors.initials: DJ
authors.lastname: Libon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001931:Brain Mapping; D003704:Dementia / Q000150:complications; D005260:Female; D006801:Humans; D049292:Leukoaraiosis / Q000209:etiology / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000209:etiology / Q000473:pathology*; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests