Alterations in Rapid Eye Movement Sleep Parameters Predict for Subsequent Progression from Mild Cognitive Impairment to Alzheimer’s Disease

Objective: Mild cognitive impairment (MCI) refers to the clinical condition between normal aging and Alzheimer’s disease (AD). Heterogeneity in this entity has also been recognized, and an accelerated rate of progression to AD was documented in some individuals diagnosed with MCI. It is important for the early detection of and intervention for AD to determine the clinical subtype of MCI with a high risk of progression to AD. Studies have demonstrated that deceased glucose metabolism or regional cerebral blood flow in the posterior cingulate may be associated with a higher risk of such progression. The aim of this study was to investigate whether any polysomnography (PSG) variables support the prediction of progression from MCI to AD. Methods: Twenty-four subjects with MCI were enrolled in this study. Clinical evaluation, cognitive screening tests, and PSG were carried out at the baseline. A diagnosis of MCI was made with standard criteria. Outcome measures were carried out to examine whether: 1) there was a significant cognitive decline, and 2) it progressed to AD according to the standard criteria for it. After a 2-year follow-up, subjects were divided into 2 groups. The MCI-AD group included subjects who progressed to AD, and the MCI-MCI group included those who did not meet the criteria for dementia. Basal PSG variables were compared between the groups. Results: Nineteen subjects completed the study. Six subjects (32%) progressed to AD within 2 years. Subjects in the MCI-AD group showed a shorter stage REM sleep (p=0.043), and a reduced REM density (p=0.043) at the baseline. Conclusion: Subjects who progressed to AD demonstrated altered REM sleep variables, yet they did not meet the criteria for clinically probable AD in the examination period. We consider that these properties may be associated with a higher risk of progression from MCI to AD. *Corresponding author: Hideto Shinno, Professor, Department of Liaison Psychiatry, Kagawa University School of Medicine,1750-1 Ikenobe, Miki, Kita, Kagawa 761-0793, Japan, Tel: +81-87-891-2165; E-mail: [email protected] Received February 24, 2016; Accepted March 04, 2016; Published March 11, 2016 Citation: Shinno H, Ishikawa I, Ando N, Matsumura Y, Horiguchi J, et al. (2016) Alterations in Rapid Eye Movement Sleep Parameters Predict for Subsequent Progression from Mild Cognitive Impairment to Alzheimer’s Disease. J Alzheimers Dis Parkinsonism 6: 218. doi: 10.4172/2161-0460.1000218 Copyright: © 2016 Shinno H, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. and frequency of nighttime awakenings, apparently occur even at an early stage of the AD process [13]. These disruptions of nighttime sleep increase in magnitude with increasing severity of dementia. AD patients present with significant losses of REM sleep and the breakdown of the sleep/wake circadian rhythm with significant amounts of sleep occurring during the day. While the characteristics of sleep architecture in AD and the influence of normal aging on the sleep architectures have been well documented, it has not been discussed whether there are predictors of progression from MCI to AD in terms of somnology. The aim of this study was to investigate whether there are any polysomnography variables in subjects with MCI that are associated with progression to AD. A shortened REM sleep is one of characteristic PSG variables in AD [13], which has been reviewed to be associated Citation: Shinno H, Ishikawa I, Ando N, Matsumura Y, Horiguchi J, et al. (2016) Alterations in Rapid Eye Movement Sleep Parameters Predict for Subsequent Progression from Mild Cognitive Impairment to Alzheimer’s Disease. J Alzheimers Dis Parkinsonism 6: 218. doi: 10.4172/21610460.1000218