0906 Feasibility of measures of sleep, circadian timing and lipid profiles for identifying mild cognitive impairment

Abstract

Abstract Introduction Sleep disruption and circadian misalignment has been evident in patients with mild cognitive impairment (MCI). Together, sleep and circadian rhythm dysregulation can contribute to dyslipidemia, which has been proposed to play crucial roles in neurodegenerative process according to its known neurotoxicity. We aimed to compare parameters regarding lipid, nocturnal sleep and circadian timing between amnestic MCI (aMCI) and normal controls (NC), and to determine whether those parameters can be associated with the presence of aMCI in the elderly. Methods Participants above 50 years old were recruited from the Dementia Clinic at Kangwon National University Hospital, and two Public Care Centers for dementia patients. Neurocognitive tests were administered to each participant. The diagnosis of aMCI was made according to Petersen’s criteria. Eighteen aMCI patients (76.6 ±6.1 years) and 21 NC (70.4±6.7years) were finally selected. Actigraphy monitoring (Actiwatch 2; Respironics, USA) was conducted for 5 days. The dim light melatonin onset (DLMO) as an indicator of circadian timing was determined from five hourly saliva samples obtained before sleep onset. Fasting plasma total cholesterol, triglycerides, high density lipoprotein cholesterol, and low density lipoprotein cholesterol were assayed. The sleep parameters, DLMO and lipid profiles were compared between the two groups. For these measures, receiver operating characteristic (ROC) analysis was performed to assess the usefulness of discriminating between the aMCI and NC. Results There were no significant differences in sleep parameters, DLMO and lipid profiles between the aMCI and NC groups. The bedtime and sleep onset were derived as indicators for discriminating aMCI (p=0.003 and p=0.054, respectively). The area under the ROC for bedtime was 0.861(cut-off scores ≥ 22:02, sensitivity= 0.76, specificity=0.75). Conclusion We did not reveal the usefulness of the DLMO and lipid profiles for identifying aMCI. However, we found that the bedtime had good discrimination power between aMCI and cognitively normal elderly, suggesting later sleep habits would be associated with the presence of aMCI in the elderly. Support (if any) Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science and ICT (2020R1F1A1050416); Research Funds from the Institute of Medical Science, Chosun University, Republic of Korea, 2022.