Department of Mental Health, San Luigi Gonzaga Hospital Medical School, University of Turin, Turin, Italy.
PLoS One. 2011;6(10):e25948. doi: 10.1371/journal.pone.0025948. Epub 2011 Oct 5.
The present study aims at clarifying the nature of the Theory of Mind (ToM) deficits associated with Amyotrophic Lateral Sclerosis (ALS). ToM is the ability to attribute mental states such as intentions and beliefs to others in order to understand and predict their behaviour and to behave accordingly. Several neuroimaging studies reported the prefrontal cortices as the brain region underlying a key ToM ability, i.e. the comprehension of social intentions. Dysfunction of the prefrontal cortices in patients with ALS has been indicated by a range of neuroimaging studies. The frontal syndrome that appears to characterize up to 50% of ALS has been noted to be similar to the profile that characterizes patients with frontotemporal dementia (FTD), a neurodegenerative condition characterised by ToM deficits. In the present paper, we hypothesize that the performance of patients with ALS is significantly worse than healthy controls' performance on tasks requiring the comprehension of social contexts, whereas patients' performance is comparable to healthy controls' performance on tasks not requiring the comprehension of social contexts. To this end, we tested 15 patients with ALS with an experimental protocol that distinguishes between private (non-social) intentions and social intentions. The pattern of results followed the experimental hypothesis: the performance of patients with ALS and healthy controls significantly differed on the comprehension of social context only, with an impairment in patients with ALS. Single case analysis confirmed the findings at an individual level. The present study is the first which has examined and compared the understanding of social and non-social contexts in patients with ALS and shown a specific and selective deficit in the former only. The current findings further support the notion of a continuum of cognitive dysfunction ranging from ALS to FTD, with parallel cognitive profiles in both disorders.
本研究旨在阐明与肌萎缩侧索硬化症（ALS）相关的心理理论（ToM）缺陷的本质。ToM 是指将心理状态（如意图和信念）归因于他人以理解和预测他们的行为并相应地行事的能力。几项神经影像学研究报告称，前额叶皮层是关键 ToM 能力（即理解社会意图）的大脑区域。一系列神经影像学研究表明，ALS 患者的前额叶皮层存在功能障碍。已经注意到，多达 50%的 ALS 患者出现的额综合征与特征为额颞叶痴呆（FTD）患者的特征相似，FTD 是一种以 ToM 缺陷为特征的神经退行性疾病。在本文中，我们假设 ALS 患者在需要理解社会背景的任务中的表现明显差于健康对照组，而患者在不需要理解社会背景的任务中的表现与健康对照组相当。为此，我们使用一种实验方案测试了 15 名 ALS 患者，该方案区分了私人（非社会）意图和社会意图。结果模式符合实验假设：只有在理解社会背景方面，ALS 患者和健康对照组的表现明显不同，且 ALS 患者的表现存在障碍。单个案例分析在个体水平上证实了这些发现。本研究首次检查和比较了 ALS 患者对社会和非社会背景的理解，并仅在前者中发现了特定和选择性的缺陷。目前的研究结果进一步支持了从 ALS 到 FTD 的认知功能障碍连续体的概念，两种疾病的认知特征相似。
