Ruby Perrine, Collette Fabienne, D'Argembeau Arnaud, Péters Frédéric, Degueldre Christian, Balteau Evelyne, Luxen André, Maquet Pierre, Salmon Eric
INSERM, U821, 69675 BRON Cedex, France.
Neurobiol Aging. 2009 Oct;30(10):1637-51. doi: 10.1016/j.neurobiolaging.2007.12.014. Epub 2008 Feb 6.
Personality changes are frequently described by caregivers of patients with Alzheimer's disease, while they are less often reported by the patients. This relative anosognosia of Alzheimer disease (AD) patients for personality changes might be related to impaired self-judgment and to decreased ability to understand their caregiver's perspective. To investigate this issue, we explored the cerebral correlates of self-assessment and perspective taking in patients with mild AD, elderly and young volunteers. All subjects assessed relevance of personality traits adjectives for self and a relative, taking either their own or their relative's perspective, during a functional imaging experiment. The comparison of subject's and relative's answers provided congruency scores used to assess self-judgment and perspective taking performance. The self-judgment "accuracy" score was diminished in AD, and when patients assessed adjectives for self-relevance, they predominantly activated bilateral intraparietal sulci (IPS). Previous studies associated IPS activation with familiarity judgment, which AD patients would use more than recollection when retrieving information to assess self-personality. When taking a third-person perspective, patients activated prefrontal regions (similarly to young volunteers), while elderly controls recruited visual associative areas (also activated by young volunteers). This suggests that mild AD patients relied more on reasoning processes than on visual imagery of autobiographical memories to take their relative's perspective. This strategy may help AD patients to cope with episodic memory impairment even if it does not prevent them from making some mind-reading errors.
阿尔茨海默病患者的照护者经常描述患者的人格变化，而患者本人较少报告这些变化。阿尔茨海默病（AD）患者对人格变化的这种相对失认可能与自我判断受损以及理解照护者观点的能力下降有关。为了研究这个问题，我们探讨了轻度AD患者、老年和年轻志愿者自我评估和换位思考的大脑相关性。在一项功能成像实验中，所有受试者从自己或其亲属的角度评估人格特质形容词与自我和亲属的相关性。比较受试者和亲属的答案得出一致性分数，用于评估自我判断和换位思考表现。AD患者的自我判断“准确性”得分降低，并且当患者评估与自我相关的形容词时，他们主要激活双侧顶内沟（IPS）。先前的研究将IPS激活与熟悉度判断相关联，AD患者在检索信息以评估自我人格时会更多地使用熟悉度判断而非回忆。当采取第三人称视角时，患者激活前额叶区域（与年轻志愿者类似），而老年对照组则募集视觉联想区域（年轻志愿者也会激活）。这表明轻度AD患者在采取亲属视角时更多地依赖推理过程而非自传体记忆的视觉表象。这种策略可能有助于AD患者应对情景记忆障碍，即使它不能防止他们犯一些读心错误。
