The cross-sectional identification of subjective cognitive decline (SCD) in cognitively normal adults is particularly important for the early effective prevention or intervention of the future development of mild cognitive impairments (MCI) or Alzheimer's disease (AD). A pre-attentive neurophysiological signal that reflects the brain's ability to detect the changes of the environment is called mismatch negativity (MMN) or its magnetic counterpart (MMNm). It has been shown that patients with MCI or AD demonstrate reduced MMN/MMNm responses, while the exact profile of MMN/MMNm in SCD is substantially unknown. We applied magnetoencephalographic recordings to interrogate MMNm activities in healthy controls (HC, n = 29) and individuals with SCD (n = 26). Furthermore, we analyzed gray matter (GM) volumes in the MMNm-related regions through voxel-based morphometry and performed apolipoprotein E4 (APOE4) genotyping for all the participants. Our results showed that there were no significant differences in GM volume and proportions of APOE4 carriers between HC and SCD groups. However, individuals with SCD exhibited weakened z-corrected MMNm responses in the left inferior parietal lobule and right inferior frontal gyrus (IFG) as compared to HC. Based on the regions showing significant between-group differences, z-corrected MMNm amplitudes of the right IFG significantly correlated with the memory performance among the SCD participants. Our data suggest that neurophysiological changes of the brain, as indexed by MMNm, precede structural atrophy in the individuals with SCD compared to those without SCD.

中文翻译：

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在主观认知能力下降中，改变的错配反应先于灰质萎缩

对认知正常的成年人主观认知衰退（SCD）的横断面鉴定对于早期有效预防或干预轻度认知障碍（MCI）或阿尔茨海默病（AD）的未来发展尤为重要。反映大脑检测环境变化能力的预注意神经生理信号称为失配负性 (MMN) 或其磁性对应物 (MMNm)。已经表明，患有 MCI 或 AD 的患者表现出 MMN/MMNm 反应降低，而 SCD 中 MMN/MMNm 的确切分布基本上是未知的。我们应用脑磁图记录来询问健康对照组（HC，n  = 29）和 SCD 患者（n = 26)。此外，我们通过基于体素的形态测量分析了 MMNm 相关区域的灰质 (GM) 体积，并对所有参与者进行了载脂蛋白 E4 (APOE4) 基因分型。我们的结果表明，HC 组和 SCD 组之间的 GM 体积和 APOE4 携带者比例没有显着差异。然而，与HC 相比，患有 SCD 的个体在左顶下小叶和右额下回 (IFG) 中表现出减弱的z校正 MMNm 反应。基于显示显着组间差异的区域，z- 右侧 IFG 的校正 MMNm 幅度与 SCD 参与者的记忆能力显着相关。我们的数据表明，与没有 SCD 的人相比，由 MMNm 索引的大脑神经生理学变化先于 SCD 患者的结构萎缩。