Linguistic markers in Parkinson’s disease (Smith et al., 2018)

Purpose: Early cognitive symptoms such as word-finding difficulty (WFD) in daily conversation are common in Parkinson’s disease (PD), but studies have been limited by a lack of feasible, quantitative measures. Linguistic analysis, focused on pauses in speech, may yield markers of impairment of cognition and communication in PD. The objective of this study was to evaluate the relationship of linguistic markers in semistructured speech to WFD symptoms and cognitive function in PD.Method: Speech recordings of description of the Cookie Theft picture in 53 patients with PD without dementia and 23 elderly controls were analyzed with Praat software. Montreal Cognitive Assessment (MoCA; Nasreddine et al., 2005), category naming fluency, and confrontation naming tests were administered. Questionnaires rating WFD symptoms and cognitive instrumental activities of daily living were completed. We determined the relationships between (a) pause length and location, (b) MoCA score, and (c) WFD symptoms, using Pearson’s correlations and multivariate regression models.Results: Compared with controls, patients with PD had more pauses within utterances as well as fewer words per minute and a lower percentage of well-formed sentences. Pauses within utterances differed significantly between PD–mild cognitive impairment and normal cognition (p < .001). Words per minute and percentage of well-formed sentences were predictive of MoCA in multivariate regression models. Pauses before verbs were associated with patient-reported severity of WFD symptoms (p = .006).Conclusions: Linguistic markers including pauses within utterances distinguish patients with PD with mild cognitive symptoms from elderly controls. These markers are associated with global cognitive function before the onset of dementia. Pauses before verbs and grammatical markers may index early cognitive symptoms such as WFD that may interfere with functional communication.
Supplemental Material S1. Baseline characteristics of Parkinson’s disease (PD) with mild cognitive impairment (MCI) and normal cognition (NC).
Supplemental Material S2. Correlations between clinical, neuropsychological, and linguistic biomarkers and word-finding difficulty (WFD) symptoms.
Supplemental Material S3. Transcription conventions.
Smith, K. M., Ash, S., Xie, S. X., & Grossman, M. (2018). Evaluation of linguistic markers of word-finding difficulty and cognition in Parkinson’s disease. Journal of Speech, Language, and Hearing Research, 61, 1691–1699. https://doi.org/10.1044/2018_JSLHR-L-17-0304

### 研究目的
日常对话中出现的找词困难（word-finding difficulty, WFD）等早期认知症状在帕金森病（Parkinson’s Disease, PD）中较为常见，但现有研究因缺乏可行的量化评估手段而受到限制。聚焦于语音停顿的语言学分析，或可成为帕金森病患者认知与交流功能受损的生物标志物。本研究旨在探讨半结构化语音中的语言学标志物与帕金森病患者找词困难症状及认知功能之间的关联。

### 研究方法
本研究采用Praat软件，对53例无痴呆的帕金森病患者与23例老年对照者完成的“偷饼干图片”描述语音录音进行分析。所有受试者均接受了蒙特利尔认知评估量表（Montreal Cognitive Assessment, MoCA；Nasreddine等，2005）、类别命名流畅性测验与对质命名测验，并完成了针对找词困难症状的评定问卷及日常工具性认知活动量表。本研究采用皮尔逊相关分析与多元回归模型，分析了（1）语音停顿的时长与位置、（2）蒙特利尔认知评估量表得分、（3）找词困难症状三者之间的关联。

### 研究结果
与对照组相比，帕金森病患者的语句内部停顿更多，每分钟朗读字数更少，完整语法语句占比更低。帕金森病伴轻度认知障碍（Mild Cognitive Impairment, MCI）患者与认知正常（Normal Cognition, NC）患者的语句内部停顿存在显著差异（p < 0.001）。多元回归分析显示，每分钟朗读字数与完整语法语句占比可预测蒙特利尔认知评估量表得分。动词前的停顿与受试者自评的找词困难症状严重程度显著相关（p = 0.006）。

### 研究结论
包括语句内部停顿在内的语言学标志物，可有效区分伴轻度认知症状的帕金森病患者与老年对照组人群。此类标志物与痴呆发病前的整体认知功能相关。动词前停顿与语法标志物或可作为找词困难等早期认知症状的评估指标，此类症状可对功能性交流造成干扰。

### 补充材料
S1 伴轻度认知障碍（MCI）与认知正常（NC）的帕金森病患者基线特征
S2 临床、神经心理学与语言学生物标志物与找词困难（WFD）症状的相关性
S3 语音转写规范

### 参考文献
Smith, K. M., Ash, S., Xie, S. X., & Grossman, M. (2018). 帕金森病患者找词困难与认知功能的语言标志物评估. 《言语、语言与听力研究杂志》, 61, 1691–1699. https://doi.org/10.1044/2018_JSLHR-L-17-0304