Ni Huangjing, Song Zijie, Liang Lei, Xing Qiaowen, Qin Jiaolong, Wu Xiaochuan
School of Geographic and Biologic Information, Nanjing University of Posts and Telecommunications, Nanjing 210003, China.
Smart Health Big Data Analysis and Location Services Engineering Lab of Jiangsu Province, Nanjing University of Posts and Telecommunications, Nanjing 210003, China.
Entropy (Basel). 2021 Nov 27;23(12):1591. doi: 10.3390/e23121591.
Individuals with subjective cognitive decline (SCD) are at high risk of developing preclinical or clinical state of Alzheimer's disease (AD). Resting state functional magnetic resonance imaging, which can indirectly reflect neuron activities by measuring the blood-oxygen-level-dependent (BOLD) signals, is promising in the early detection of SCD. This study aimed to explore whether the nonlinear complexity of BOLD signals can describe the subtle differences between SCD and normal aging, and uncover the underlying neuropsychological implications of these differences. In particular, we introduce amplitude-aware permutation entropy (AAPE) as the novel measure of brain entropy to characterize the complexity in BOLD signals in each brain region of the Brainnetome atlas. Our results demonstrate that AAPE can reflect the subtle differences between both groups, and the SCD group presented significantly decreased complexities in subregions of the superior temporal gyrus, the inferior parietal lobule, the postcentral gyrus, and the insular gyrus. Moreover, the results further reveal that lower complexity in SCD may correspond to poorer cognitive performance or even subtle cognitive impairment. Our findings demonstrated the effectiveness and sensitiveness of the novel brain entropy measured by AAPE, which may serve as the potential neuroimaging marker for exploring the subtle changes in SCD.
主观认知下降（SCD）个体处于发展为阿尔茨海默病（AD）临床前期或临床状态的高风险中。静息态功能磁共振成像通过测量血氧水平依赖（BOLD）信号间接反映神经元活动，在SCD的早期检测中具有前景。本研究旨在探讨BOLD信号的非线性复杂性是否能够描述SCD与正常衰老之间的细微差异，并揭示这些差异潜在的神经心理学意义。具体而言，我们引入幅度感知排列熵（AAPE）作为脑熵的新度量，以表征脑网络组图谱中每个脑区BOLD信号的复杂性。我们的结果表明，AAPE能够反映两组之间的细微差异，且SCD组在颞上回、顶下小叶、中央后回和脑岛回的子区域表现出显著降低的复杂性。此外，结果进一步揭示，SCD中较低的复杂性可能对应较差的认知表现甚至细微的认知障碍。我们的研究结果证明了通过AAPE测量的新型脑熵的有效性和敏感性，其可能作为探索SCD细微变化的潜在神经影像学标志物。
