P896
Poster Presentations: P4
ipsilateral hippocampus, frontal and temporal cortices (Figure 1) . Conclusions: WM connectivity in dementia patients was regionally reduced in comparison to MCI patients. Such structural connectivity declines possibly reflects a higher magnitude of microstructural WM abnormalities in dementia patients. WM tract alterations might be associated with language, attention, and working memory performance and relate to key clinical features of AD-related cognitive decline.
P4-303
COGNITIVE FUNCTION AND TRACTOGRAPHY OF WHITE MATTER TRACTS CROSSING HYPERINTENSITIES IN ELDERLY PERSONS
Angeles Garcia1, William Reginold1, Angela Luedke2, Justine Itorralba2, Juan Fernandez-Ruiz3, Jenifer Reinold4, Omar Islam1, 1Queen’s University, Kingston, Ontario, Canada; 2Queen’s University, Kingston, Ontario, Canada; 3Queen’s University, Mexico City, Mexico; 4University of Toronto, Toronto, Ontario, Canada. Contact e-mail:
[email protected] Background: There is clinical need for magnetic resonance imaging (MRI) measures of white matter hyperintenstity (WMH) severity that relate to performance on neuropsychological testing. This study used diffusion tensor imaging (DTI) tractography to determine if there was an association between the integrity of tracts crossing WMH and cognitive function. Methods: Brain T2 fluid attenuated inversion recovery-weighted (FLAIR) and diffusion tensor MRI scans were acquired in thirty-four persons with and without dementia, 60 of age or older. All subjects completed a battery of neuropsychological tests including Trails in seconds, Wechsler Memory Scale-III Longest span backwards and Longest span forward, Stroop test and California Verbal Learning Test Long delay free recall. Dementia was diagnosed following the NINCDS-ADRDA criteria. Tractography was generated by the Fiber Assignment by Continuous Tracking method. WMH were identified on T2 FLAIR scans. The fractional anisotropy (FA) and mean diffusivity (MD) were quantified for all the tracts that crossed WMH (WMH-tract). We studied the association between performance on a battery of cognitive tests with WMH-tract FA and MD while controlling for age, sex, dementia diagnosis and total volume of WMH. Results: There was a statistically significant association between MoCA scores and the MD of WMH-tracts (regression coefficient: 14060, 95% CI: 1 788 to 26 320, n¼34, p¼0.03) as well as between performance on the Wechsler Memory Scale-III Longest span forward and the MD of WMH-tracts (coefficient: -12940, 95% CI: -22 940 to -2 934, n¼24, p¼0.01). There was no association, however, between the MoCA scores and the FA of WMH-tracts (coefficient: -15.57, 95% CI: -39.81 to 8.67, n¼ 34, p¼ 0.20) or focused attention and FA of WMH-tracts (Longest span forward test, coefficient: 10.19, 95% CI: -12.40 to 32.77, n¼24, p¼0.36). Conclusions: This study demonstrated a novel correlation between the MD of WMH-tracts and cognitive function. The mean diffusivity of tracts crossing WMH represents a novel measure of WMH burden. In the elderly population with a high prevalence of WMH, DTI tractography could become helpful in triaging patients for further cognitive testing.
P4-304
Figure 1. DMN sub region mask used to over lap each statistical map and to calculate the aver age z-score ALFF and functional connectivity measures. Dark blue corresponds to the ventromedial prefrontal cortex; purple corresponds to the medial parietal cortex (PCC + precuneus); green corresponds to the inferior parietal lobe; and red corresponds to the medial temporal lobe. and functional connectivity, as well as their possible implications on cognition in patients with mild AD and amnestic mild cognitive impairment (aMCI) and healthy controls. In addition, we evaluated the differences both in connectivity and ALFF values between these groups. Methods: We recruited 29 controls, 20 aMCI and 32 mild AD patients. To identify the DMN, functional connectivity was calculated by placing a seed in the posterior cingulate cortex (PCC). Within the DMN mask
DIFFERENCES AND THE RELATIONSHIP BETWEEN DMN INTRINSIC ACTIVITY AND FUNCTIONAL CONNECTIVITY IN MILD AD AND AMCI
Marina Weiler, Brunno Machado Campos, Mateus Nogueira, Camila Teixeira, Benito Damasceno, Fernando Cendes, Marcio Balthazar, UNICAMP, Campinas, Brazil. Contact e-mail: weiler_marina@yahoo. com.br Background: There is evidence that the Default Mode Network (DMN) functional connectivity is impaired in Alzheimer’s disease (AD) and few studies also reported a decrease in DMN intrinsic activity, measured by the amplitude of low frequency fluctuations (ALFF). In this study, we analyzed the relationship between DMN intrinsic activity
Figure 2. Correlation values between cognitive scores and sub regions connectivity values. MMSE: mini-mental status examination; RAVLT: Rey auditory verbal learning test; RAVLT-A7: delayed recall of Rey auditory verbal learning test; RC-FP: Rey auditory verbal learning test true recognition (i.e.. recognition minus false positives). *p
