Inter-individual variability in discourse informativeness in elderly populations

An increasing number of studies focus on discourse production in patients with neurodegenerative diseases and underline its clinical usefulness. However, if this is to be used as a clinical tool, one needs to consider how normal discourse varies within cognitively unimpaired elderly populations. In the current study, the aim has been to investigate discourse macrolinguistic variability. For this, 123 participants aged between 55 and 84 were recruited. A cluster analysis of their discourse macrolinguistic features was conducted. Then, cluster characterisation based on socio-demographic and linguistic performance was tested (fluency, naming, syntax and spelling). This method aims to identify various profiles of speaker and informativeness and then see if inter-individual variability may be related to socio-demographic and/or linguistic aspects. Four clusters of informativeness were found but no socio-demographic features appeared significant. The fourth cluster, defined as ‘off topic’, had lower performance during linguistic tasks than others and thus the boundary between normality and pathology should be questioned.越来越多的研究聚焦于神经退行性疾病患者的话语产出，并强调了其临床应用价值。然而，若要将该指标作为临床工具使用，则需考量认知正常老年群体内部的正常话语变异模式。本研究旨在探究话语宏观语言学变异性（discourse macrolinguistic variability）。为此，本研究招募了123名年龄介于55至84岁之间的受试者，并对其话语宏观语言学特征开展了聚类分析。随后，基于社会人口统计学特征与语言表现（包括流畅性、命名能力、句法能力及拼写能力）对聚类结果进行了特征刻画与验证。本研究方法旨在识别不同的说话者画像与信息丰富度类型，并探究个体间的变异性是否与社会人口统计学及/或语言学特征相关。研究共得到四类信息丰富度聚类结果，但未发现具有统计学显著性的社会人口统计学特征差异。被定义为‘偏离主题（off topic）’的第四类聚类在语言任务中的表现劣于其余聚类，因此有必要对正常状态与病理状态之间的分界阈值提出质疑。