Liu Yong-Shou, Wang Yong-Ming, Zha Ding-Jun
Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Air Force Medical University, Xi'an, China.
Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom.
Front Psychiatry. 2021 Nov 1;12:772068. doi: 10.3389/fpsyt.2021.772068. eCollection 2021.
Sleep disorders (SLD) are supposed to be associated with increased risk and development of Alzheimer's disease (AD), and patients with AD are more likely to show SLD. However, neurobiological performance of patients with both AD and SLD in previous studies is inconsistent, and identifying specific patterns of the brain functional network and structural characteristics in this kind of comorbidity is warranted for understanding how AD and SLD symptoms interact with each other as well as finding effective clinical intervention. Thus, the aims of this systematic review were to summarize the relevant findings and their limitations and provide future research directions. A systematic search on brain functional and structural changes in patients with both AD and SLD was conducted from PubMed, Web of Science, and EMBASE databases. Nine original articles published between 2009 and 2021 were included with a total of 328 patients with comorbid AD and SLD, 367 patients with only AD, and 294 healthy controls. One single-photon emission computed tomography study and one multislice spiral computed tomography perfusion imaging study investigated changes of cerebral blood flow; four structural magnetic resonance imaging (MRI) studies investigated brain structural changes, two of them used whole brain analysis, and another two used regions of interest; two resting-state functional MRI studies investigated brain functional changes, and one 2-deoxy-2-(18F)fluoro-d-glucose positron emission tomography (18F-FDG-PET) investigated 18F-FDG-PET uptake in patients with comorbid AD and SLD. Findings were inconsistent, ranging from default mode network to sensorimotor cortex, hippocampus, brain stem, and pineal gland, which may be due to different imaging techniques, measurements of sleep disorder and subtypes of AD and SLD. Our review provides a systematic summary and promising implication of specific neuroimaging dysfunction underlying co-occurrence of AD and SLD. However, limited and inconsistent findings still restrict its neurobiological explanation. Further studies should use unified standards and comprehensive brain indices to investigate the pathophysiological basis of interaction between AD and SLD symptoms in the development of the disease spectrums.
睡眠障碍（SLD）被认为与阿尔茨海默病（AD）的风险增加及病情发展相关，且AD患者更易出现SLD。然而，既往研究中AD合并SLD患者的神经生物学表现并不一致，确定这种共病情况下脑功能网络的特定模式和结构特征，对于理解AD和SLD症状如何相互作用以及找到有效的临床干预措施很有必要。因此，本系统综述的目的是总结相关研究结果及其局限性，并提供未来的研究方向。我们从PubMed、科学网和EMBASE数据库中对AD合并SLD患者的脑功能和结构变化进行了系统检索。纳入了2009年至2021年间发表的9篇原创文章，共328例AD合并SLD患者、367例仅患AD的患者和294例健康对照。一项单光子发射计算机断层扫描研究和一项多层螺旋计算机断层扫描灌注成像研究调查了脑血流量的变化；四项结构磁共振成像（MRI）研究调查了脑结构变化，其中两项采用全脑分析，另外两项采用感兴趣区域；两项静息态功能MRI研究调查了脑功能变化，一项2-脱氧-2-（18F）氟-D-葡萄糖正电子发射断层扫描（18F-FDG-PET）研究调查了AD合并SLD患者的18F-FDG-PET摄取情况。研究结果不一致，涉及从默认模式网络到感觉运动皮层、海马体、脑干和松果体等不同部位，这可能是由于成像技术、睡眠障碍测量方法以及AD和SLD的亚型不同所致。我们的综述对AD和SLD共病情况下特定神经影像学功能障碍进行了系统总结并提出了有前景的见解。然而，有限且不一致的研究结果仍然限制了对其神经生物学的解释。未来的研究应采用统一标准和综合脑指标，以研究疾病谱发展过程中AD和SLD症状相互作用的病理生理基础。
