A physiological signature of sound meaning in dementia.
A physiological signature of sound meaning in dementia.
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DOI：
10.1016/j.cortex.2016.01.007
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发表时间：
2016-04
期刊：
影响因子：
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通讯作者：
Warren JD
中科院分区：
文献类型：
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作者：
Fletcher PD;Nicholas JM;Downey LE;Golden HL;Clark CN;Pires C;Agustus JL;Mummery CJ;Schott JM;Rohrer JD;Crutch SJ;Warren JD
感官对象的意义通常在行为和生物学上是显著的，而语义显著性的解码在痴呆症中可能是脆弱的。然而，感觉语义加工如何与编码客体显著性的生理机制联系起来，以及这种联系如何受到神经退行性疾病的影响，目前尚不清楚。在这里，我们使用复杂声音的范例来解决这个问题。我们使用瞳孔测量法比较典型痴呆综合征（行为变异性额颞叶痴呆- bvFTD，语义痴呆- SD，进行性非流利性失语症- PNFA，典型阿尔茨海默病- AD）患者与健康老年人对真实和合成非语言声音的生理反应。非语言听觉语义能力通过一种新的模态内声音分类任务进行评估，瞳孔反应的神经解剖学关联通过基于体素的脑磁共振图像形态测量（VBM）进行评估。在考虑了情感刺激因素后，SD和AD患者对真实声音和合成声音的瞳孔反应明显高于健康对照组。与健康对照组相比，bvFTD、SD和AD组存在非语言听觉语义缺陷，非语言听觉语义表现与患者群体中瞳孔对真实声音和合成声音的反应增强程度呈负相关。兴趣区分析表明，上丘和左前颞叶皮层的整体瞳孔反应性和差异瞳孔反应性分别与声音语义内容的神经解剖学关联。我们的研究结果表明，在语义系统受损的情况下，听觉语义模糊的自主编码可能构成神经退行性疾病的一种新的生理特征。
The meaning of sensory objects is often behaviourally and biologically salient and decoding of semantic salience is potentially vulnerable in dementia. However, it remains unclear how sensory semantic processing is linked to physiological mechanisms for coding object salience and how that linkage is affected by neurodegenerative diseases. Here we addressed this issue using the paradigm of complex sounds. We used pupillometry to compare physiological responses to real versus synthetic nonverbal sounds in patients with canonical dementia syndromes (behavioural variant frontotemporal dementia – bvFTD, semantic dementia – SD; progressive nonfluent aphasia – PNFA; typical Alzheimer's disease – AD) relative to healthy older individuals. Nonverbal auditory semantic competence was assessed using a novel within-modality sound classification task and neuroanatomical associations of pupillary responses were assessed using voxel-based morphometry (VBM) of patients' brain MR images. After taking affective stimulus factors into account, patients with SD and AD showed significantly increased pupil responses to real versus synthetic sounds relative to healthy controls. The bvFTD, SD and AD groups had a nonverbal auditory semantic deficit relative to healthy controls and nonverbal auditory semantic performance was inversely correlated with the magnitude of the enhanced pupil response to real versus synthetic sounds across the patient cohort. A region of interest analysis demonstrated neuroanatomical associations of overall pupil reactivity and differential pupil reactivity to sound semantic content in superior colliculus and left anterior temporal cortex respectively. Our findings suggest that autonomic coding of auditory semantic ambiguity in the setting of a damaged semantic system may constitute a novel physiological signature of neurodegenerative diseases.