Tales Andrea, Butler Stuart
Department of Care of the Elderly, The BRACE Centre, University of Bristol, Blackberry Hill Hospital, Bristol, UK.
Neuroreport. 2006 Jun 26;17(9):887-90. doi: 10.1097/01.wnr.0000223383.42295.fa.
Mismatch negativity has been found to decline in amplitude with increasing age and also in Alzheimer's disease. It has been suggested that the reduction in amplitude of mismatch negativity in Alzheimer's disease is the result of fatigue rather than a generalized decline in neuronal response. We tested this hypothesis by measuring the effect of time on task on the visual mismatch negativity in both normal aging and in Alzheimer's disease. In older adults, visual mismatch negativity showed a reduction in amplitude, which did not vary with time on task. This argues against fatigue as the cause of visual mismatch negativity amplitude reduction in normal ageing. In Alzheimer's disease, visual mismatch negativity was virtually absent in responses to the first 16 deviant stimuli but present in response to subsequent deviants. This is opposite to the effect predicted by the fatigue hypothesis. It suggests that individuals with Alzheimer's disease are initially refractory to stimulus change.
失匹配负波已被发现其波幅会随着年龄增长以及在阿尔茨海默病中而下降。有人提出，阿尔茨海默病中失匹配负波波幅的降低是疲劳的结果，而非神经元反应的普遍衰退。我们通过测量任务时间对正常衰老和阿尔茨海默病中视觉失匹配负波的影响来检验这一假设。在老年人中，视觉失匹配负波波幅降低，且不随任务时间而变化。这反驳了疲劳是正常衰老中视觉失匹配负波波幅降低原因的观点。在阿尔茨海默病中，对最初16个偏差刺激的反应中几乎没有视觉失匹配负波，但对随后的偏差刺激有反应。这与疲劳假说所预测的效应相反。这表明阿尔茨海默病患者最初对刺激变化具有 refractory（此处refractory 未给出准确中文释义，可根据语境推测为“不应性”之类的意思，暂保留英文）。
