PATTERNS OF GRAY MATTER VOLUME LOSS IN ALZHEIMER’S DISEASE WITH SLEEP DISTURBANCE

Abstract

Previous studies using animal model and imaging modalities showed anatomical structures related to sleep physiology. Also recent researches revealed the relationship between sleep problems and cognitive dysfunction. Despite these evidences, there have been few studies of structural changes in Alzheimer's disease with sleep problems. We aimed to evaluate the effects of nighttime sleep on cognition and neuropsychological symptoms in AD, and to investigate whether there are differences of gray matter(GM) loss patterns between Alzheimer's disease (AD) with sleep problems (poor sleeper AD) and without sleep problems(good sleeper AD). We included consecutive 32 patients with AD and 14 controls. All of the participants underwent detailed neuropsychological evaluation using SNSB and NPI-K, the sleep characteristic questionnaire using Korean version of the Pittsburgh Sleep Quality Index (PSQI-K) and 3D T1-weighted MRI at 3 Tesla. VBM analysis using FSL and hippocampal subfields volume analyses using Freesurfer were performed. AD patients showed significantly lower PSQI-K total score and higher NPI total score than controls (p<0.05). In AD, sleep latency was found to be negatively correlated with visual memory (p<0.05) after adjusting for age and education, while sleep duration was positively correlated with visual and verbal memory (p<0.05). Comparison of cognitive function showed worse performances of verbal memory and visual memory in poor sleeper AD (PSQI total score >5) than in good sleeper AD (p<0.05). GM volume was significantly reduced in bilateral cingulate gyrus in poor sleeper AD compared to good sleeper AD. Our results suggest that prolonged sleep duration and seep latency were correlated with cognitive dysfunction, especially memory dysfunction. GM volume loss in bilateral cingulate gyrus in poor sleeper AD support previous neuroimaging results in insomnia.