Alzheimer's Disease (AD) dementia is a progressive neurodegenerative disease that negatively impacts patients' cognitive ability. Previous studies have demonstrated that changes in naturalistic language samples can be useful for early screening of AD dementia. However, the nature of language deficits often requires test administrators to use various speech elicitation techniques during spontaneous language assessments to obtain enough propositional utterances from dementia patients. This could lead to the ``observer's effect'' on the downstream analysis that has not been fully investigated. Our study seeks to quantify the influence of test administrators on linguistic features in dementia assessment with two English corpora the ``Cookie Theft'' picture description datasets collected at different locations and test administrators show different levels of administrator involvement. Our results show that the level of test administrator involvement significantly impacts observed linguistic features in patient speech. These results suggest that many of significant linguistic features in the downstream classification task may be partially attributable to differences in the test administration practices rather than solely to participants' cognitive status. The variations in test administrator behavior can lead to systematic biases in linguistic data, potentially confounding research outcomes and clinical assessments. Our study suggests that there is a need for a more standardized test administration protocol in the development of responsible clinical speech analytics frameworks.

翻译：阿尔茨海默病（AD）痴呆是一种进行性神经退行性疾病，会对患者的认知能力产生负面影响。先前的研究表明，自然语言样本的变化可用于AD痴呆的早期筛查。然而，语言缺陷的性质通常要求测试管理员在自发性语言评估中使用各种言语诱发技术，以从痴呆患者处获得足够的命题性话语。这可能导致下游分析中存在尚未被充分研究的“观察者效应”。本研究旨在通过两个英语语料库——“饼干盗窃”图片描述数据集（在不同地点收集，且测试管理员表现出不同程度的参与度）——量化测试管理员对痴呆评估中语言特征的影响。我们的结果表明，测试管理员的参与程度显著影响患者言语中观察到的语言特征。这些发现提示，下游分类任务中的许多显著语言特征可能部分归因于测试管理实践的差异，而非仅由参与者的认知状态所致。测试管理员行为的差异可能导致语言数据出现系统性偏差，进而可能混淆研究结果和临床评估。本研究指出，在开发负责任的临床言语分析框架时，需要建立更标准化的测试管理协议。