Hewitt Samuel Rc, White Alice J, Mason Sarah L, Barker Roger A
John Van Geest Centre for Brain Repair, Department of Clinical Neuroscience, University of Cambridge, Cambridge, Cambridgeshire, UK.
Max Planck UCL Centre for Computational Psychiatry and Ageing Research, University College London, London, UK.
BMJ Neurol Open. 2022 Apr 5;4(1):e000268. doi: 10.1136/bmjno-2022-000268. eCollection 2022.
Insight is an important predictor of quality of life in Huntington's disease and other neurodegenerative conditions. However, estimating insight with traditional methods such as questionnaires is challenging and subjected to limitations. This cross-sectional study experimentally quantified metacognitive insight into cognitive performance in Huntington's disease gene carriers.
We dissociated perceptual decision-making performance and metacognitive insight into performance in healthy controls (n=29), premanifest (n=19) and early-manifest (n=10) Huntington's disease gene carriers. Insight was operationalised as the degree to which a participant's confidence in their performance was informative of their actual performance (metacognitive efficiency) and estimated using a computational model (HMeta-d').
We found that premanifest and early-manifest Huntington's disease gene carriers were impaired in making perceptual decisions compared with controls. Gene carriers required more evidence in favour of the correct choice to achieve similar performance and perceptual impairments were increased in those with manifest disease. Surprisingly, despite marked perceptual impairments, Huntington's disease gene carriers retained metacognitive insight into their perceptual performance. This was the case after controlling for confounding variables and regardless of disease stage.
We report for the first time a dissociation between impaired cognition and intact metacognition (trial-by-trial insight) in the early stages of a neurodegenerative disease. This unexpected finding contrasts with the prevailing assumption that cognitive deficits are associated with impaired insight. Future studies should investigate how intact metacognitive insight could be used by some early Huntington's disease gene carriers to positively impact their quality of life.
自知力是亨廷顿舞蹈病及其他神经退行性疾病生活质量的重要预测指标。然而，使用问卷等传统方法评估自知力具有挑战性且存在局限性。这项横断面研究通过实验量化了亨廷顿舞蹈病基因携带者对认知表现的元认知自知力。
我们将健康对照者（n = 29）、症状前（n = 19）和症状早期（n = 10）的亨廷顿舞蹈病基因携带者的知觉决策表现和对表现的元认知自知力区分开来。自知力被定义为参与者对自己表现的信心能反映其实际表现的程度（元认知效率），并使用计算模型（HMeta-d'）进行评估。
我们发现，与对照组相比，症状前和症状早期的亨廷顿舞蹈病基因携带者在进行知觉决策时存在障碍。基因携带者需要更多支持正确选择的证据才能达到相似的表现，且在出现明显症状的患者中知觉障碍有所增加。令人惊讶的是，尽管存在明显的知觉障碍，亨廷顿舞蹈病基因携带者仍保留了对其知觉表现的元认知自知力。在控制了混杂变量之后以及无论疾病处于何阶段，都是如此。
我们首次报告了在神经退行性疾病早期认知受损与元认知完整（逐次试验自知力）之间的分离。这一意外发现与认知缺陷与自知力受损相关的普遍假设形成了对比。未来的研究应调查一些早期亨廷顿舞蹈病基因携带者如何利用完整的元认知自知力对其生活质量产生积极影响。
