Department of Occupational Therapy and Graduate Institute of Behavioral Sciences, Chang Gung University, Taoyuan, Taiwan.
Laboratory of Brain Imaging and Neural Dynamics (BIND Lab), Chang Gung University, Taoyuan, Taiwan.
CNS Neurosci Ther. 2021 Oct;27(10):1136-1145. doi: 10.1111/cns.13691. Epub 2021 Aug 4.
Mismatch negativity (MMN) reflects the functional integrity of sensory memory function. With the advantages of independence of individual's focused attention and behavioral cooperation, this neurophysiological signal is particularly suitable for investigating elderly with cognitive decline such as amnestic mild cognitive impairment (aMCI). However, the existing results remain substantially inconsistent whether these patients show deficits of MMN. In order to reconcile the previous disputes, the present study used magnetoencephalography combined with distributed source imaging methods to determine the source-level magnetic mismatch negativity (MMNm) in aMCI.
A total of 26 healthy controls (HC) and 26 patients with aMCI underwent an auditory oddball paradigm during the MEG recordings. MMNm amplitudes and latencies in the bilateral superior temporal gyrus, inferior frontal gyrus, and inferior parietal lobule (IPL) were compared between HC and aMCI groups. The correlations of MMNm responses with performance of auditory/verbal memory tests were examined. Finally, MMNm and its combination with verbal/auditory memory tests were submitted to receiver operating characteristic (ROC) curve analysis.
Compared to HC, patients with aMCI showed significantly delayed MMNm latencies in the IPL. Among the patients with aMCI, longer MMNm latencies of left IPL were associated with lower scores of Chinese Version Verbal Learning Test (CVVLT). The ROC curve analysis revealed that the combination of MMNm latencies of left IPL and CVVLT scores yielded a moderate accuracy in the discrimination of aMCI from HC at an individual level.
Our data suggest dysfunctional MMNm in patients with aMCI, particularly in the IPL.
失匹配负波（MMN）反映了感觉记忆功能的功能完整性。这种神经生理信号具有个体专注注意力和行为合作的独立性优势，特别适合研究认知能力下降的老年人，如遗忘型轻度认知障碍（aMCI）。然而，这些患者是否存在 MMN 缺陷，现有的结果仍然存在很大的不一致性。为了解决之前的争议，本研究采用脑磁图结合分布式源成像方法，确定了 aMCI 患者的源水平磁失匹配负波（MMNm）。
共有 26 名健康对照者（HC）和 26 名 aMCI 患者在 MEG 记录期间接受了听觉Oddball 范式。比较了 HC 和 aMCI 组双侧颞上回、额下回和顶下小叶（IPL）的 MMNm 振幅和潜伏期。检查了 MMNm 反应与听觉/言语记忆测试表现的相关性。最后，将 MMNm 及其与言语/听觉记忆测试的组合提交给接受者操作特征（ROC）曲线分析。
与 HC 相比，aMCI 患者的 IPL 中的 MMNm 潜伏期明显延迟。在 aMCI 患者中，左 IPL 的 MMNm 潜伏期较长与中国版词语学习测验（CVVLT）的得分较低有关。ROC 曲线分析表明，左 IPL 的 MMNm 潜伏期和 CVVLT 得分的组合在个体水平上对 aMCI 与 HC 的区分具有中等准确性。
我们的数据表明，aMCI 患者存在功能失调的 MMN，特别是在 IPL。
