Cheng Chia-Hsiung, Hsiao Fu-Jung, Hsieh Yu-Wei, Wang Pei-Ning
Department of Occupational Therapy, Graduate Institute of Behavioral Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan.
Front Aging Neurosci. 2020 Feb 25;12:39. doi: 10.3389/fnagi.2020.00039. eCollection 2020.
Patients with amnestic mild cognitive impairment (aMCI) demonstrate significant cognitive deficits, especially in the memory aspect. The memory deficiency might be attributed to the difficulties in the inhibitory function to suppress redundant stimuli. Sensory gating (SG) refers to the attenuation of neural responses to the second identical stimulus in a paired-click paradigm, in which auditory stimuli are delivered in pairs with inter-stimulus intervals (ISI) of 500 ms and inter-pair intervals of 6-8 s. It is considered as an electrophysiological signal to reflect the brain's automatic response to gate out repetitive sensory inputs. However, there has been no study systematically investigating SG function in aMCI patients. Thus, the present study used magnetoencephalography (MEG) to record neuromagnetic responses to a paired-click paradigm in 23 healthy controls (HC) and 26 aMCI patients. The Stimulus 2/Stimulus 1 (S2/S1) amplitude ratio was used to represent the SG function. Compared to HC, aMCI patients showed M50 SG deficits in the left inferior frontal gyrus (IFG) and right inferior parietal lobule (IPL). M100 SG defects were also observed in the right IPL. Based on the ROIs showing significant between-group SG differences, we found that a more deficient M50 SG function in the right IPL was associated with poorer performance in the immediate recall of Logic Memory (LM), Chinese Version Verbal Learning Test (CVVLT) and Digit Span Backward (DSB) Test. Furthermore, the M50 SG ratios of the right IPL together with the neuropsychological performance of LM and CVVLT demonstrated very good accuracy in the discrimination of aMCI from HC. In conclusion, compared to HC, aMCI patients showed a significant SG deficit in the right IPL, which was correlated with the auditory short-term memory function. We suggest the combination of SG in the right IPL, LM and CVVLT to be sensitive indicators to differentiate aMCI patients from HC.
遗忘型轻度认知障碍（aMCI）患者表现出明显的认知缺陷，尤其是在记忆方面。记忆缺陷可能归因于抑制冗余刺激的抑制功能存在困难。感觉门控（SG）是指在双声点击范式中对第二个相同刺激的神经反应减弱，在该范式中，听觉刺激以500毫秒的刺激间隔（ISI）和6 - 8秒的双刺激间隔成对呈现。它被认为是一种反映大脑自动筛选重复感觉输入的电生理信号。然而，尚无研究系统地调查aMCI患者的SG功能。因此，本研究使用脑磁图（MEG）记录了23名健康对照者（HC）和26名aMCI患者对双声点击范式的神经磁反应。刺激2/刺激1（S2/S1）振幅比用于代表SG功能。与HC相比，aMCI患者在左侧额下回（IFG）和右侧顶下小叶（IPL）表现出M50 SG缺陷。在右侧IPL也观察到M100 SG缺陷。基于显示组间SG差异显著的感兴趣区域（ROI），我们发现右侧IPL中更缺乏的M50 SG功能与逻辑记忆（LM）即时回忆、中文版言语学习测验（CVVLT）和数字广度倒背（DSB）测验的较差表现相关。此外，右侧IPL的M50 SG比率与LM和CVVLT的神经心理学表现一起，在区分aMCI和HC方面显示出非常高的准确性。总之，与HC相比，aMCI患者在右侧IPL表现出显著的SG缺陷，这与听觉短期记忆功能相关。我们建议将右侧IPL的SG、LM和CVVLT结合起来作为区分aMCI患者和HC的敏感指标。
