Functional neuroimaging techniques (i.e. single photon emission computed tomography, positron emission tomography, and functional magnetic resonance imaging) have been used to assess the neural correlates of anosognosia in mild cognitive impairment (MCI) and Alzheimer’s disease (AD). A systematic review of this literature was performed, following the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement, on PubMed, EMBASE, and PsycINFO databases. Twenty-five articles met all inclusion criteria. Specifically, four brain connectivity and 21 brain perfusion, metabolism, and activation articles. Anosognosia is associated in MCI with frontal lobe and cortical midline regional dysfunction (reduced perfusion and activation), and with reduced parietotemporal metabolism. Reduced within and between network connectivity is observed in the default mode network regions of AD patients with anosognosia compared to AD patients without anosognosia and controls. During initial stages of cognitive decline in anosognosia, reduced indirect neural activity (i.e. perfusion, metabolism, and activation) is associated with the cortical midline regions, followed by the parietotemporal structures in later stages and culminating in frontotemporal dysfunction. Although the current evidence suggests differences in activation between AD or MCI patients with anosognosia and healthy controls, more evidence is needed exploring the differences between MCI and AD patients with and without anosognosia using resting state and task related paradigms.

中文翻译：

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轻度认知障碍和阿尔茨海默病中失认症的功能神经相关性：系统评价。


功能性神经影像技术（即单光子发射计算机断层扫描、正电子发射断层扫描和功能性磁共振成像）已被用于评估轻度认知障碍（MCI）和阿尔茨海默病（AD）中失认症的神经相关性。根据系统评价和荟萃分析的首选报告项目声明，在 PubMed、EMBASE 和 PsycINFO 数据库上对该文献进行了系统评价。二十五篇文章符合所有纳入标准。具体来说，有 4 篇大脑连接和 21 篇大脑灌注、新陈代谢和激活文章。 MCI 中的失认症与额叶和皮质中线区域功能障碍（灌注和激活减少）以及顶颞叶代谢减少有关。与没有失认症的 AD 患者和对照组相比，在患有失认症的 AD 患者的默认模式网络区域中观察到网络内部和网络之间的连接性减少。在失认症认知能力下降的初始阶段，间接神经活动（即灌注、代谢和激活）减少与皮质中线区域有关，随后是顶颞结构，最终导致额颞叶功能障碍。尽管目前的证据表明患有失认症的 AD 或 MCI 患者与健康对照之间的激活存在差异，但需要更多证据使用静息状态和任务相关范式探索患有或不患有失认症的 MCI 和 AD 患者之间的差异。