Dept. Translation & Language Sciences, Universitat Pompeu Fabra, Carrer Roc Boronat, 138, Barcelona 08018, Spain.
Dept. Translation & Language Sciences, Universitat Pompeu Fabra, Carrer Roc Boronat, 138, Barcelona 08018, Spain; Intitut Català de Recerca i Estudis Avançats (ICREA), Barcelona, Spain, Passeig de Lluís Companys, 23, 08010 Barcelona, Spain.
J Commun Disord. 2022 May-Jun;97:106214. doi: 10.1016/j.jcomdis.2022.106214. Epub 2022 Mar 23.
The profile of spontaneous speech in Alzheimer's disease (AD) includes increased pausing as a window into cognitive decline. We here aimed to further characterize the pausing profile of AD by linking pauses to the syntactic positions in which they appear and disease progression.
Speech was obtained through a picture description task, thus minimizing demands on episodic memory (EM), from a group of mild (N = 21) and moderate AD (N = 19), and healthy elderly controls (N = 40). Pauses were sub-indexed according to whether they occurred within-clauses, clause-initially, or utterance-initially, and whether they preceded nouns, verbs, or adjectives/adverbs, when occurring within-clauses. Additionally, relations to verbal fluency (VF) measures at the single-word level were explored.
Pause rate but not duration distinguished controls from both AD groups, while fillers did not distinguish any groups. The analysis by syntactic position revealed a highly differentiated picture, with largest effect sizes of significant group differences seen in the utterance-initial pause rate. The two AD groups patterned differently when compared to controls, while none of the measures differentiated the AD groups. Specifically, moderate but not mild AD differed from controls in clause-initial pauses, while mild but not moderate AD differed from controls in within-clause positions. At the within-clause level, the effect dividing controls from mild-AD was specifically driven by pauses ahead of nouns. A significant negative correlation emerged between pausing rate in spontaneous speech and VF measures in the mild-AD group only.
Increased empty (non-filled) pauses in AD are not confined to pauses in within-clause positions, which are most directly related to problems in the retrieval of words. Even in early disease stages, where these within-clause pause effects are seen, they are confined to nouns, revealing a grammatically specific problem possibly related to the referencing of objects. At all disease stages, pauses increase in utterance-sized units of structure, indicating progressive problems in the creative configuration of complete thoughts.
阿尔茨海默病（AD）自发言语的特征包括停顿增加，这可以作为认知能力下降的窗口。我们旨在通过将停顿与出现停顿的句法位置以及疾病进展联系起来，进一步描述 AD 的停顿特征。
通过图片描述任务获得言语，从而最大程度地减少对情景记忆（EM）的需求，该任务来自轻度（N=21）和中度 AD（N=19）以及健康老年人对照组（N=40）。根据停顿是在分句内、分句首还是句首出现，以及在分句内出现时是否在名词、动词或形容词/副词之前，将停顿进行子索引。此外，还探讨了与单词语流畅性（VF）测量的关系。
停顿率而不是停顿时间可以区分对照组和 AD 组，而填充词不能区分任何组。根据句法位置的分析显示出高度分化的情况，在句首停顿率方面，有显著的组间差异的效应量最大。与对照组相比，两个 AD 组的模式不同，而没有任何措施可以区分 AD 组。具体来说，中度 AD 与对照组不同，表现在分句首的停顿，而轻度 AD 与对照组不同，表现在分句内位置。在分句内水平上，将轻度 AD 与对照组区分开来的效果主要是由名词之前的停顿驱动的。仅在轻度 AD 组中出现了停顿率与 VF 测量值之间的显著负相关。
AD 中的空（未填充）停顿增加不仅限于与单词检索问题最直接相关的分句内位置的停顿。即使在早期疾病阶段，也会出现这些分句内停顿效应，而且仅限于名词，这表明可能与对象引用有关的语法特异性问题。在所有疾病阶段，停顿都会增加结构的句子大小单位，这表明在创造性配置完整思想方面存在进行性问题。
