IntroductionPosterior cortical atrophy (PCA) is a neurodegenerative syndrome characterized by progressive impairment in visuospatial and perceptual function linked to atrophy of the occipito-parietal cortex. Besides the salient visual impairment, several studies have documented subtle changes in language may also be present. Sentence repetition is a highly constrained linguistic task involving multiple linguistic and cognitive processes and have been shown to be impaired in other AD spectrum disorders, with little consensus on its relevance in PCA. This aim of this study was to further delineate the linguistic and cognitive features of impaired language in PCA using a sentence repetition task.MethodSeven PCA patients and 16 healthy controls verbally repeated 16 sentences from the Boston Diagnostic Aphasia Examination. Responses were transcribed orthographically and coded for accuracy (percentage accuracy; percentage Correct Information Units; Levenshtein Distance) and for temporal characteristics (preparation duration (ms); utterance duration (ms); silent pause duration (ms); speech duration (ms); dysfluency duration (ms)). The potential modulating effects of attentional control and working memory capacity were explored.ResultsPCA patients showed lower overall accuracy with retained semantic content of the sentences, and lower phonological accuracy. Temporal measures revealed longer preparation and utterance duration for PCA patients compared to controls, alongside longer speech duration but comparable dysfluency duration. PCA patients also showed comparable silent pause duration to controls. Attentional control, measured using the Hayling sentence completion task, predicted accuracy of sentence repetition.DiscussionThe findings suggest that sentence repetition is impaired in PCA and is characterized by phonological, response planning and execution difficulties, underpinned in part by attentional control mechanisms. The emerging profile of language impairment in PCA suggests vulnerability of similar cognitive systems to other Alzheimer’s syndromes, with subtle differences in clinical presentation.

中文翻译：

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后皮质萎缩的继发性语言障碍：句子重复的见解

简介后皮质萎缩（PCA）是一种神经退行性综合征，其特征是与枕顶叶皮质萎缩相关的视觉空间和知觉功能进行性损害。除了明显的视力障碍外，一些研究表明语言也可能存在细微的变化。句子重复是一项高度受限的语言任务，涉及多种语言和认知过程，并且已被证明在其他 AD 谱系障碍中受到损害，但对其在 PCA 中的相关性几乎没有达成共识。本研究的目的是通过句子重复任务进一步描述 PCA 语言障碍的语言和认知特征。方法 7 名 PCA 患者和 16 名健康对照者口头重复波士顿诊断失语症检查中的 16 个句子。响应以正字法转录并编码以确保准确性（准确度百分比；正确信息单位百分比；编辑距离）和时间特征（准备持续时间（毫秒）；发声持续时间（毫秒）；静默停顿持续时间（毫秒）；讲话持续时间（毫秒）；以及时间特征（准备持续时间（毫秒））。不流畅持续时间（毫秒））。探讨了注意力控制和工作记忆能力的潜在调节作用。结果PCA患者保留句子语义内容的总体准确性较低，语音准确性较低。时间测量显示，与对照组相比，PCA 患者的准备和言语持续时间更长，言语持续时间更长，但不流利的持续时间相当。 PCA 患者也表现出与对照组相当的无声停顿持续时间。使用 Hayling 句子完成任务测量的注意力控制可预测句子重复的准确性。讨论研究结果表明 PCA 中句子重复受到损害，其特点是语音、反应计划和执行困难，部分由注意力控制机制支撑。 PCA 中新出现的语言障碍表明，类似的认知系统对其他阿尔茨海默病也很脆弱，但临床表现存在细微差异。