Right anterior temporal lobe dysfunction underlies theory of mind impairments in semantic dementia
Right anterior temporal lobe dysfunction underlies theory of mind impairments in semantic dementia
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DOI：
10.1093/brain/awu003
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发表时间：
2014-04-01
期刊：
影响因子：
14.5
通讯作者：
Piguet, Olivier
中科院分区：
文献类型：
--
作者：
Irish, Muireann;Hodges, John R.;Piguet, Olivier
语意性痴呆虽然被定义为一种语言障碍，但可能伴随着心智理论的损伤。通过结构MRI， Irish等人揭示了右前颞叶退化是该综合征的精神破坏理论的基础。这些发现强调了这些结构在社会认知中的关键作用。语义性痴呆是一种进行性神经退行性疾病，其特征是由左前颞叶退化引起的情态性和深刻的语义知识丧失。虽然语意性痴呆传统上被认为是一种语言障碍，但患者在行为和社会情感功能上表现出显著的改变。最近的证据表明，在语义性痴呆患者中，心智理论能力受损的主要是左偏侧；然而，目前尚不清楚语义障碍在多大程度上导致了这些缺陷。此外，这种紊乱的神经解剖学特征仍然未知。在这里，我们试图确定左主导语义性痴呆患者（n = 11）的心理理论表现的神经相关性，与行为变异额颞叶痴呆（n = 10）和阿尔茨海默病（n = 10）的疾病匹配病例和健康老年人（n = 14）作为对照参与者。参与者完成了一个简单的卡通任务，在这个任务中，他们被要求描述身体和心理理论的场景。无论何种亚量表，语意性痴呆患者相对于对照组表现出明显的损伤；然而，当我们对语义理解进行共变时，只有心智理论缺陷持续存在。基于体素的形态测量分析显示，语义痴呆组的右侧颞叶前部结构萎缩，包括右侧颞梭状皮质、右侧颞下回、双侧颞极和杏仁核，与心智理论损伤显著相关。我们的研究结果表明，语义痴呆的认知功能明显中断，超出了语言领域，而不仅仅是由于语义处理障碍。右侧颞前叶结构的显著累及表明，随着疾病的发展，病理侵入对侧半球预示着该综合征中社会认知缺陷的发生。
Semantic dementia, although conceptualized as a language disorder, may be accompanied by impairments in theory of mind. Using structural MRI, Irish et al. reveal that right anterior temporal lobe degeneration underlies theory of mind disruption in this syndrome. These findings underscore the crucial role of these structures for social cognition.Semantic dementia is a progressive neurodegenerative disorder characterized by the amodal and profound loss of semantic knowledge attributable to the degeneration of the left anterior temporal lobe. Although traditionally conceptualized as a language disorder, patients with semantic dementia display significant alterations in behaviour and socioemotional functioning. Recent evidence points to an impaired capacity for theory of mind in predominantly left-lateralized cases of semantic dementia; however, it remains unclear to what extent semantic impairments contribute to these deficits. Further the neuroanatomical signature of such disturbance remains unknown. Here, we sought to determine the neural correlates of theory of mind performance in patients with left predominant semantic dementia (n = 11), in contrast with disease-matched cases with behavioural-variant frontotemporal dementia (n = 10) and Alzheimer's disease (n = 10), and healthy older individuals (n = 14) as control participants. Participants completed a simple cartoons task, in which they were required to describe physical and theory of mind scenarios. Irrespective of subscale, patients with semantic dementia exhibited marked impairments relative to control subjects; however, only theory of mind deficits persisted when we covaried for semantic comprehension. Voxel-based morphometry analyses revealed that atrophy in right anterior temporal lobe structures, including the right temporal fusiform cortex, right inferior temporal gyrus, bilateral temporal poles and amygdalae, correlated significantly with theory of mind impairments in the semantic dementia group. Our results point to the marked disruption of cognitive functions beyond the language domain in semantic dementia, not exclusively attributable to semantic processing impairments. The significant involvement of right anterior temporal structures suggests that with disease evolution, the encroachment of pathology into the contralateral hemisphere heralds the onset of social cognitive deficits in this syndrome.