0281 FRONTAL Β-AMYLOID BURDEN AND SLEEP DURATION IN AGING

Recent studies suggest relationships between sleep disturbances and early signs of Alzheimer’s disease pathology (Spira, 2013). The aim of this study was to examine relationships between objectively measured sleep and β-amyloid (Aβ) burden in aging subjects. 59 elderly (79.7 years; 44% female) without dementia, sleep disorders and medications were included. Actigraphy was used to measure sleep duration and fragmentation over 7–8 nights. Participants underwent MRI anatomic scans and [18F]-Flutemetamol PET-CT scans. First, PET scans were spatially normalized into the MNI space and included in whole brain multiple regression analyses. Secondly, MRI scans were segmented using FreeSurfer v5.3 to provide several regions of interest (ROIs) including frontal area, anterior and posterior cingulate cortex, precuneus and hippocampus. Regional distribution volume ratios were calculated for each ROI and included in multivariate regression models. Both analyses were conducted to explore relationships between Aβ burden (outcome) and each sleep parameter (predictor) corrected for age, gender and time between actigraphy and PET scans. In the voxel wise analysis, short sleep duration was associated with Aβ burden in frontal area including left inferior frontal gyrus (trend for the right part), left middle and superior frontal gyrus, bilateral precentral, left insula and bilateral anterior cingulate cortex (p<0.05, FDRc corrected). Sub-threshold results were observed between short sleep duration and Aβ burden in hippocampal regions. These last results were confirmed by the ROI analysis (F=2.763, p<0.05 for left hippocampus and a trend was observed for the right part F=2.375, p=0.06). In contrast, no significant association was observed with sleep fragmentation in either analysis. In elderly, sleep duration but not sleep quality was associated with Aβ burden in frontal and hippocampal regions. Level of Aβ in brain interstitial fluid has been shown to decrease during sleep in mice (Kang, 2009), suggesting that short sleep duration may cause or exacerbate Aβ accumulation. GE Healthcare provided the [18F]-Flutemetamol for PET imaging.