Department of Neurology, Xuanwu Hospital of Capital Medical University, No.45 Street Changchun, District Xichen, Beijing, 100053, China.
School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing, 100081, China.
Brain Imaging Behav. 2020 Dec;14(6):2187-2201. doi: 10.1007/s11682-019-00169-6.
Alzheimer's disease (AD) is the most common neurodegenerative disease in elderly individuals. We conducted this study to examine whether alterations in the fractional amplitudes of low-frequency fluctuations (fALFF) in the AD spectrum were frequency-dependent and symptom-relevant. A total of 43 patients with subjective cognitive decline (SCD), 52 with amnestic mild cognitive impairment (aMCI), 44 with Alzheimer's dementia (d-AD) and 55 well-matched controls participated in resting-state functional magnetic resonance imaging (rs-fMRI) scans. The amplitudes were measured using fALFF within the slow-4 (0.027-0.073 Hz) and slow-5 (0.01-0.027 Hz) bands. Repeated-measures analysis of variance was performed on fALFF within two bands and correlated with neuropsychological test scores. The significant main effects of frequency and group on fALFF differed widely across brain regions. There were more varied areas in the slow-5 band than the slow-4 band. The fALFF associated with primary disease effects was mainly distributed in the parietal lobe. Obvious frequency band and group interaction effects were observed in the left angular gyrus, left calcarine fissure and surrounding cortex, left superior cerebellum, left cuneus and right lingual gyrus. Neuropsychological tests scores were significantly correlated with the fALFF magnitude of the left cuneus and right lingual in the slow-5 band. Our results suggested that the AD continuum had abnormal amplitudes in intrinsic brain activity, and these abnormalities were frequency-dependent and mainly associated with the slow-5 band rather than the slow-4 band. This may guide the frequency choice of future rs-fMRI studies and provide new insights into the neuropathophysiology of AD.
阿尔茨海默病（AD）是老年人中最常见的神经退行性疾病。我们进行这项研究是为了检查 AD 谱中低频波动（fALFF）分数幅度的改变是否与频率有关，是否与症状有关。共有 43 例主观认知减退（SCD）患者、52 例遗忘型轻度认知障碍（aMCI）患者、44 例阿尔茨海默病痴呆（d-AD）患者和 55 例匹配良好的对照组参与了静息态功能磁共振成像（rs-fMRI）扫描。使用 fALFF 在慢 4（0.027-0.073 Hz）和慢 5（0.01-0.027 Hz）频段内测量幅度。在两个频段内对 fALFF 进行重复测量方差分析，并与神经心理学测试评分相关。频率和组的显著主效应在脑区之间差异很大。慢 5 波段的变化区域比慢 4 波段更多。与原发性疾病效应相关的 fALFF 主要分布在顶叶。在左侧角回、左侧距状裂及周围皮层、左侧小脑上脚、左侧楔叶和右侧舌回观察到明显的频率带和组间交互作用效应。神经心理学测试评分与慢 5 波段左侧楔叶和右侧舌回的 fALFF 幅度显著相关。我们的结果表明，AD 连续体存在内在脑活动幅度异常，这些异常与频率有关，主要与慢 5 波段有关，而与慢 4 波段无关。这可能指导未来 rs-fMRI 研究的频率选择，并为 AD 的神经病理生理学提供新的见解。
