Metacognitive insight into cognitive performance in pre and early-stage Huntington’s disease

ABSTRACT Objectives 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 subject to limitations. This cross-sectional study experimentally quantified metacognitive insight into cognitive performance in Huntington’s disease gene-carriers. Methods 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). Results We found that pre and early-manifest Huntington’s disease gene-carriers were impaired in making perceptual decisions compared to 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. Conclusion 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.