Department of Neuropsychiatry, Seoul National University Bundang Hospital, Seongnam, Korea.
Curr Alzheimer Res. 2020;17(13):1195-1207. doi: 10.2174/1567205018666210216084534.
While identifying Alzheimer's Disease (AD) in its early stages is crucial, traditional neuropsychological tests tend to lack sensitivity and specificity for its diagnosis. Neuropsychological studies have reported visual processing deficits of AD, and event-related potentials (ERPs) are suitable to investigate pre-attentive processing with superior temporal resolution.
This study aimed to investigate visual attentional characteristics of adults with AD, from pre-attentive to attentive processing, using a visual oddball task and ERPs.
Cognitively normal elderly controls (CN) and patients with probable AD (AD) were recruited. Participants performed a three-stimulus visual oddball task and were asked to press a designated button in response to the target stimuli. The amplitudes of 4 ERPs were analyzed. Mismatchnegativity (vMMN) was analyzed around the parieto-occipital and temporo-occipital regions. P3a was analyzed around the fronto-central regions, whereas P3b was analyzed around the centro-parietal regions.
Late vMMN amplitudes of the AD group were significantly smaller than those of the CN group, while early vMMN amplitudes were comparable. Compared to the CN group, P3a amplitudes of the AD group were significantly smaller for the infrequent deviant stimuli, but the amplitudes for the standard stimuli were comparable. Lastly, the AD group had significantly smaller P3b amplitudes for the target stimuli compared to the CN group.
Our findings imply that AD patients exhibit pre-attentive visual processing deficits, known to affect later higher-order brain functions. In a clinical setting, the visual oddball paradigm could be used to provide helpful diagnostic information since pre-attentive ERPs can be induced by passive exposure to infrequent stimuli.
虽然在早期识别阿尔茨海默病（AD）至关重要，但传统的神经心理学测试往往缺乏对其诊断的敏感性和特异性。神经心理学研究报告称 AD 存在视觉加工缺陷，事件相关电位（ERPs）适合于用超时间分辨率研究前注意加工。
本研究旨在使用视觉Oddball 任务和 ERPs 研究 AD 成人从前注意到注意加工的视觉注意力特征。
招募认知正常的老年对照组（CN）和可能患有 AD 的患者（AD）。参与者执行三刺激视觉 Oddball 任务，并被要求在目标刺激出现时按下指定按钮。分析了 4 个 ERPs 的振幅。在顶枕和颞枕区域周围分析失匹配负波（vMMN）。在额中央区域分析 P3a，而在中央顶区域分析 P3b。
AD 组的晚期 vMMN 振幅明显小于 CN 组，而早期 vMMN 振幅相似。与 CN 组相比，AD 组对罕见偏差刺激的 P3a 振幅明显较小，但对标准刺激的振幅相似。最后，与 CN 组相比，AD 组的目标刺激的 P3b 振幅明显较小。
我们的研究结果表明 AD 患者存在前注意视觉加工缺陷，这已知会影响后期的高级脑功能。在临床环境中，由于可以通过被动暴露于罕见刺激来诱发前注意 ERPs，因此视觉 Oddball 范式可以提供有帮助的诊断信息。
