B – 6 White Matter Burden and Neuropsychological Performance in an Older Adult Clinical Sample

Abstract Objective Investigate the association of white matter hyperintensities (WMH) burden on routine clinical MRI and neuropsychological performance in a clinical sample comprised of older adults. Method Two groups were selected based on MRI Results 1) minimal/mild WMH (n = 19) and 2) moderate/severe WMH (n = 20). All patients had significant cerebrovascular risk factors and among them, patients with neurodegenerative etiologies were excluded. Composite scores for four cognitive domains were created by averaging standardized test scores: Language (Boston Naming Test, F-A-S Test, Animals), Working Memory (Digit Span Backward, Digit Span Sequencing, Arithmetic), Executive Functioning (Delis-Kaplan Executive Function System [DKEFS] Color-Word Interference, F-A-S Test), and Processing Speed (DKEFS Color Naming, DKEFS Word Naming). Results A multivariate analysis of covariance was conducted to determine whether WMH burden was associated with cognitive performance. Age and education were included as covariates. Overall multivariate effect of WMH was not statistically significant. Age was not a significant multivariate predictor. However, education showed a significant multivariate effect, Wilks’ Λ = .71, F(4, 32) = 3.26, p = .02, partial η2 = .29. Follow-up univariate tests revealed a significant effect of WMH on working memory composite scores, F(1, 35) = 9.89, p < .01, partial η2 = .22. Patients with moderate to severe WMH burden were associated with impairments in working memory relative to those with minimal to mild WMH burden. No significant group differences were found in language functioning, processing speed, or executive functioning. Conclusion Findings suggest that WMH burden is associated with impairments in working memory, independent of age and education.