Oxford Project to Investigate Memory and Ageing (OPTIMA), Nuffield Department of Clinical Medicine, University of Oxford, UK.
Cortex. 2013 Mar;49(3):668-78. doi: 10.1016/j.cortex.2012.04.011. Epub 2012 May 8.
Patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI) may be unaware of their cognitive impairment. The neuroanatomical mechanisms underlying this symptom, termed anosognosia or impaired self-awareness, are still poorly understood. In the present study we aimed to explore the functional correlates of self-awareness in patients with MCI and AD.
Fifty-one participants (17 healthy elderly, 17 patients with MCI, and 17 patients with AD), each accompanied by a study partner, took part in a functional magnetic resonance imaging (fMRI) study, in which they were presented with questions regarding themselves (Self condition) or their study partner (Other condition). The study partner was asked to complete a paper questionnaire answering the same questions so the responses of participant and study partner could be compared and "discrepancy" scores calculated for each of the 2 conditions (Self and Other).
Behavioural results showed that AD patients had significantly higher "Self discrepancy scores" than controls and MCI patients, whereas there were no significant differences between groups for "Other discrepancy scores". Imaging results showed a significant group-by-condition interaction in brain activation in medial prefrontal and anterior temporal regions, with AD patients showing significantly decreased activation in these regions only for the Self condition. There were no significant differences between Self and Other conditions in either control or MCI groups, suggesting that, in these groups, Self- and Other-appraisal share similar neuroanatomical substrates.
Decreased functional activation of medial prefrontal and anterior temporal cortices is associated with impaired self-awareness in AD patients. This dysfunction, which is specific for Self- but not for Other-appraisal, may be a contributing factor to anosognosia in AD.
患有阿尔茨海默病（AD）和轻度认知障碍（MCI）的患者可能没有意识到自己的认知障碍。这种被称为否认或自我意识受损的症状的神经解剖学机制仍知之甚少。在本研究中，我们旨在探索 MCI 和 AD 患者自我意识的功能相关性。
51 名参与者（17 名健康老年人、17 名 MCI 患者和 17 名 AD 患者），每人由一名研究伙伴陪同，参加了一项功能磁共振成像（fMRI）研究，在该研究中，他们被问及与自己（自我条件）或研究伙伴（他人条件）有关的问题。要求研究伙伴填写一份纸质问卷，回答相同的问题，以便比较参与者和研究伙伴的回答，并为每个条件（自我和他人）计算“差异”分数。
行为结果表明，AD 患者的“自我差异分数”明显高于对照组和 MCI 患者，而对照组和 MCI 患者之间的“他人差异分数”没有显著差异。成像结果显示，在中前额叶和前颞叶区域的大脑激活中存在显著的组-条件交互作用，只有 AD 患者在自我条件下显示出这些区域的激活显著降低。在对照组或 MCI 组中，自我和他人条件之间没有显著差异，这表明在这些组中，自我和他人评估具有相似的神经解剖学基础。
中前额叶和前颞叶皮层的功能激活减少与 AD 患者的自我意识受损有关。这种功能障碍，特异性地存在于自我评估中，而不存在于他人评估中，可能是 AD 中否认的一个促成因素。
