Ramanan Siddharth, de Souza Leonardo Cruz, Moreau Noémie, Sarazin Marie, Teixeira Antônio L, Allen Zoe, Guimarães Henrique C, Caramelli Paulo, Dubois Bruno, Hornberger Michael, Bertoux Maxime
Department of Neurology, Manipal Hospitals, Bangalore, India.
Federal University of Minas Gerais, Belo Horizonte, Brazil.
Cortex. 2017 Mar;88:8-18. doi: 10.1016/j.cortex.2016.11.014. Epub 2016 Nov 30.
Whether theory of mind (ToM) is preserved in Alzheimer's disease (AD) remains a controversial subject. Recent studies have showed that performance on some ToM tests might be altered in AD, though to a lesser extent than in behavioural-variant Frontotemporal Dementia (bvFTD). It is however, unclear if this reflects a genuine impairment of ToM or a deficit secondary to the general cognitive decline observed in AD. Aiming to investigate the cognitive determinants of ToM performance in AD, a data-mining study was conducted in 29 AD patients then replicated in an independent age-matched group of 19 AD patients to perform an independent replication of the results. 44 bvFTD patients were included as a comparison group. All patients had an extensive neuropsychological examination. Hierarchical clustering analyses showed that ToM performance clustered with measures of executive functioning (EF) in AD. ToM performance was also specifically correlated with the executive component extracted from a principal component analysis. In a final step, automated linear modelling conducted to determine the predictors of ToM performance showed that 48.8% of ToM performance was significantly predicted by executive measures. Similar findings across analyses were observed in the independent group of AD patients, thereby replicating our results. Conversely, ToM impairments in bvFTD appeared independent of other cognitive impairments. These results suggest that difficulties of AD patients on ToM tests do not reflect a genuine ToM deficit, rather mediated by general (and particularly executive) cognitive decline. They also suggest that EF has a key role in mental state attribution, which support interacting models of ToM functioning. Finally, our study highlights the relevancy of data-mining statistical approaches in clinical and cognitive neurosciences.
心理理论（ToM）在阿尔茨海默病（AD）中是否保留仍是一个有争议的话题。最近的研究表明，AD患者在一些ToM测试中的表现可能会发生改变，尽管程度比行为变异型额颞叶痴呆（bvFTD）要小。然而，目前尚不清楚这是否反映了ToM的真正受损，还是AD中观察到的一般认知衰退继发的缺陷。为了研究AD患者ToM表现的认知决定因素，对29名AD患者进行了一项数据挖掘研究，然后在一个由19名年龄匹配的AD患者组成的独立组中进行重复，以对结果进行独立复制。将44名bvFTD患者作为对照组。所有患者都进行了广泛的神经心理学检查。分层聚类分析表明，AD患者的ToM表现与执行功能（EF）测量结果聚集在一起。ToM表现也与主成分分析中提取的执行成分特别相关。在最后一步，通过自动线性建模来确定ToM表现的预测因素，结果表明48.8%的ToM表现可由执行测量显著预测。在独立的AD患者组中观察到了跨分析的类似结果，从而复制了我们的结果。相反，bvFTD患者的ToM损伤似乎与其他认知损伤无关。这些结果表明，AD患者在ToM测试中的困难并不反映真正的ToM缺陷，而是由一般（特别是执行）认知衰退介导的。它们还表明，EF在心理状态归因中起关键作用，这支持了ToM功能的交互模型。最后，我们的研究强调了数据挖掘统计方法在临床和认知神经科学中的相关性。
