Introduction: 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.

Objective: 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.

Methods: 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.

Results: 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.

Conclusion: 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.

简介：虽然在早期阶段识别阿尔茨海默病 (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了 AD 的视觉处理缺陷，事件相关电位 (ERP) 适合研究具有卓越时间分辨率的预注意处理。

目的：本研究旨在使用视觉古怪任务和 ERP 来调查 AD 成人的视觉注意特征，从预注意到注意处理。

方法：招募认知正常的老年人对照（CN）和可能患有 AD（AD）的患者。参与者执行了一个三刺激视觉古怪任务，并被要求按下指定的按钮以响应目标刺激。分析了4个ERP的振幅。围绕顶枕区和颞枕区分析错配负性 (vMMN)。P3a 在额中央区域周围进行分析，而 P3b 在中央顶区域周围进行分析。

结果：AD组晚期vMMN波幅明显小于CN组，而早期vMMN波幅相当。与 CN 组相比，AD 组的 P3a 振幅对于不常见的异常刺激显着较小，但标准刺激的振幅具有可比性。最后，与 CN 组相比，AD 组的目标刺激 P3b 幅度明显更小。

结论：我们的研究结果表明 AD 患者表现出预先注意的视觉处理缺陷，已知会影响以后的高阶大脑功能。在临床环境中，视觉古怪范式可用于提供有用的诊断信息，因为被动暴露于不频繁的刺激可以诱发预先注意的 ERP。