Ries Michele L, Jabbar Britta M, Schmitz Taylor W, Trivedi Mehul A, Gleason Carey E, Carlsson Cynthia M, Rowley Howard A, Asthana Sanjay, Johnson Sterling C
Geriatric Research Education and Clinical Center, William S. Middleton VA Hospital, Madison, Wisconsin 53705, USA.
J Int Neuropsychol Soc. 2007 May;13(3):450-61. doi: 10.1017/S1355617707070488.
Awareness of cognitive dysfunction shown by individuals with Mild Cognitive Impairment (MCI), a condition conferring risk for Alzheimer's disease (AD), is variable. Anosognosia, or unawareness of loss of function, is beginning to be recognized as an important clinical symptom of MCI. However, little is known about the brain substrates underlying this symptom. We hypothesized that MCI participants' activation of cortical midline structures (CMS) during self-appraisal would covary with level of insight into cognitive difficulties (indexed by a discrepancy score between patient and informant ratings of cognitive decline in each MCI participant). To address this hypothesis, we first compared 16 MCI participants and 16 age-matched controls, examining brain regions showing conjoint or differential BOLD response during self-appraisal. Second, we used regression to investigate the relationship between awareness of deficit in MCI and BOLD activity during self-appraisal, controlling for extent of memory impairment. Between-group comparisons indicated that MCI participants show subtly attenuated CMS activity during self-appraisal. Regression analysis revealed a highly significant relationship between BOLD response during self-appraisal and self-awareness of deficit in MCI. This finding highlights the level of anosognosia in MCI as an important predictor of response to self-appraisal in cortical midline structures, brain regions vulnerable to changes in early AD.
轻度认知障碍（MCI）患者表现出的认知功能障碍意识存在差异，MCI是一种会增加患阿尔茨海默病（AD）风险的病症。失认症，即对功能丧失的无意识，正开始被视为MCI的一种重要临床症状。然而，对于这种症状背后的脑基质却知之甚少。我们假设，MCI参与者在自我评估过程中皮质中线结构（CMS）的激活情况会与对认知困难的洞察水平相关（通过每个MCI参与者的患者与 informant 对认知衰退评分之间的差异分数来衡量）。为了验证这一假设，我们首先比较了16名MCI参与者和16名年龄匹配的对照组，检查在自我评估过程中显示联合或差异BOLD反应的脑区。其次，我们使用回归分析来研究MCI中对缺陷的意识与自我评估期间的BOLD活动之间的关系，并控制记忆损害的程度。组间比较表明，MCI参与者在自我评估过程中CMS活动略有减弱。回归分析显示，自我评估期间的BOLD反应与MCI中对缺陷的自我意识之间存在高度显著的关系。这一发现凸显了MCI中的失认症水平作为皮质中线结构（易在早期AD中发生变化的脑区）对自我评估反应的重要预测指标。
