BACKGROUND Diagnosis of prodromal Alzheimer's disease (AD) still represents a hot topic and there is a growing interest for the detection of early and non-invasive biomarkers. Although progressive episodic memory impairment is the typical predominant feature of AD, communicative difficulties can be already present at the early stages of the disease. OBJECTIVE This study investigated the narrative discourse production deficit as a hallmark of CSFdefined prodromal AD and its correlation with cerebral hypoperfusion pattern. METHODS Narrative assessment with a multilevel procedure for discourse analysis was conducted on 28 subjects with Mild Cognitive Impairment (15 MCI due to AD; 13 MCI non-AD) and 28 healthy controls. The diagnostic workup included CSF AD biomarkers. Cerebral hypoperfusion pattern was identified by SPECT image processing. RESULTS The results showed that the discourse analysis of global coherence and lexical informativeness indexes allowed to identify MCI due to AD from MCI non-AD and healthy subjects. These findings allow to hypothesize that the loss of narrative efficacy could be a possible early clinical hallmark of Alzheimer's disease. Furthermore, a significant correlation of global coherence and lexical informativeness reduction with the SPECT hypoperfusion was found in the dorsal aspect of the anterior part of the left inferior frontal gyrus, supporting the hypothesis that this area has a significant role in communicative efficacy, and in particular, in semantic selection executive control. CONCLUSION This study contributes to the understanding of the neural networks for language processing and their involvement in prodromal Alzheimer's disease. It also suggests an easy and sensitive tool for clinical practice that can help identifying individuals with prodromal Alzheimer's disease.

中文翻译：

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连接语音障碍是脑脊液定义的阿尔茨海默氏病的早期标志，并与脑灌注不足相关。

背景技术前驱性阿尔茨海默氏病（AD）的诊断仍然是一个热门话题，并且对早期和非侵入性生物标志物的检测越来越感兴趣。尽管进行性的发作性记忆障碍是AD的典型主要特征，但在疾病的早期阶段就已经存在沟通困难。目的本研究调查叙述性话语产生不足，作为脑脊液定义的前驱性AD的标志及其与脑灌注不足模式的相关性。方法对28例轻度认知障碍（AD导致15 MCI；非AD引起13 MCI）和28例健康对照者进行了多级话语分析叙事评估。诊断检查包括CSF AD生物标志物。通过SPECT图像处理鉴定出脑灌注不足模式。结果结果表明，对整体连贯性和词汇信息性指数进行的话语分析可以从非MCI和健康受试者中识别出AD所致的MCI。这些发现可以假设，失去叙述功效可能是阿尔茨海默氏病的早期临床标志。此外，在左下额回前部的背侧发现了整体连贯性和词汇信息减少与SPECT灌注不足之间的显着相关性，支持了以下假设：该区域在交流功效中具有重要作用，尤其是，在语义选择执行控制中。结论本研究有助于理解用于语言处理的神经网络及其在前驱性阿尔茨海默氏病中的参与。