School of Foreign Studies, Xi'an Jiaotong University, Xi'an, China.
Institute of Applied Linguistics, Zhejiang University, Hangzhou, China.
Int J Lang Commun Disord. 2024 Sep-Oct;59(5):1672-1690. doi: 10.1111/1460-6984.13023. Epub 2024 Feb 26.
Previous studies on language production in normal ageing have primarily focused on distinct dimensions of older adults' spoken language performance, such as fluency and complexity. However, little attention has been paid to the complex, interconnected relations between these dimensions. Additionally, older adults have been treated as a homogeneous group, with little consideration for the differential characteristics of language performance across different stages of ageing.
This study aims to investigate how increasing age impacts Chinese seniors' oral language performance, focusing on fluency (articulation rate and dysfluency rate), complexity (lexical and syntactic) and the potential interactions between these dimensions.
METHODS & PROCEDURES: Spontaneous oral narratives were collected from 60 normally ageing individuals, who were categorised into three groups: young-old (60-69 years old), middle-old (70-79 years old) and old-old (≥80 years old). Four measures for assessing language performance, namely, articulation rate, dysfluency rate, lexical complexity and syntactic complexity, were derived from the oral narratives. Dynamic systems techniques, including moving correlations, locally estimated scatterplot smoothing and Monte Carlo simulations, were employed for data analysis.
OUTCOMES & RESULTS: This study revealed two major findings. First, across different age groups, the seniors' oral narratives significantly differed in the aspect of articulation rate and syntactic complexity. Specifically, both the young-old and the middle-old groups exhibited significantly higher articulation rates than the old-old group; the middle-old group also demonstrated significantly higher syntactic complexity compared to the old-old group. Second, the distinct subsystems (i.e., articulation rate, dysfluency rate, lexical and syntactic complexity) of seniors' oral narratives demonstrated varying interactions across different stages of ageing. While these subsystems tended to coordinate with each other in young-old individuals, they exhibited a greater tendency to compete in middle-old and old-old individuals.
CONCLUSIONS & IMPLICATIONS: The findings reveal that subsystems of older adults' oral narratives display varying interactions with the increase of age, indicating that focusing solely on one dimension of language performance may result in inaccurate or misleading conclusions. Therefore, a multi-index comprehensive assessment should be employed for the enhancement of clinical evaluations of language performance in older adults. Additionally, it is vital to consider the interactional patterns (i.e., support or competition) between language subsystems when assessing language performance in normal ageing.
What is already known on the subject Previous research on language production in normal ageing has primarily focused on distinct dimensions of older adults' spoken language performance, such as fluency, vocabulary richness and grammatical complexity, overlooking the intricate interconnections between these dimensions. However, investigating these connections is significant for a thorough and in-depth understanding of language production in late adulthood, which operates as a system comprising interconnected components. Furthermore, existing studies have predominantly treated older adults as a homogeneous group, comparing their language use to that of young people. This approach lacks justification, given the substantial variations in language use among seniors at different stages of ageing. What this paper adds to existing knowledge The present findings illuminate the dynamic nature of language production in normal ageing. Not only do the distinct dimensions or subsystems of older adults' oral narratives (e.g., articulation rate, dysfluency rate, syntactic complexity) change with age, but more important, the ways in which these subsystems interact with each other also evolve with age, resulting in changing states of spoken language production in the ageing process. More specifically, our study provides evidence that the interactions among subsystems of older adults' oral narratives predominately transition from supportive relationships in earlier stages to competitive ones at later stages of ageing. What are the potential or actual clinical implications of this work? The present study suggests the use of multiple linguistic indices related to various aspects of language performance to assess the spoken language production of older adults. This is highlighted by the observation that various dimensions of older adults' oral narratives continuously interact with one another across different stages of ageing, and hence focusing solely on one dimension of language performance tends to lead to inaccurate or misleading results. Additionally, the patterns of interaction (i.e., support or competition) between different dimensions of language performance may reflect older adults' capacity to coordinate and control attentional resources and therefore should be taken into consideration in clinical evaluations of language performance in older adults.
先前关于正常衰老过程中语言产生的研究主要集中在老年人口语表现的不同维度上，例如流畅性和复杂性。然而，这些维度之间的复杂、相互关联的关系却很少受到关注。此外，老年人被视为一个同质群体，几乎没有考虑到不同衰老阶段语言表现的差异特征。
本研究旨在探讨年龄增长如何影响中国老年人的口语表现，重点关注流畅性（发音速度和不流畅率）、复杂性（词汇和句法）以及这些维度之间的潜在相互作用。
从 60 名正常衰老的个体中收集自发的口头叙述，并将他们分为三组：年轻老年人（60-69 岁）、中年老年人（70-79 岁）和年老老年人（≥80 岁）。从口头叙述中得出评估语言表现的四个指标，即发音速度、不流畅率、词汇复杂性和句法复杂性。采用动态系统技术，包括移动相关、局部估计散点平滑和蒙特卡罗模拟，进行数据分析。
本研究揭示了两个主要发现。首先，在不同的年龄组中，老年人的口头叙述在发音速度和句法复杂性方面存在显著差异。具体来说，年轻老年人和中年老年人的发音速度均显著高于年老老年人；中年老年人的句法复杂性也显著高于年老老年人。其次，老年人口头叙述的不同子系统（即发音速度、不流畅率、词汇和句法复杂性）在不同的衰老阶段表现出不同的相互作用。虽然这些子系统在年轻老年人中倾向于相互协调，但在中年老年人和年老老年人中，它们表现出更大的相互竞争倾向。
研究结果表明，老年人的口头叙述的子系统随着年龄的增长表现出不同的相互作用，这表明仅关注语言表现的一个维度可能会导致不准确或误导性的结论。因此，应采用多指标综合评估方法来提高对老年人语言表现的临床评估。此外，在评估正常衰老过程中的语言表现时，考虑语言子系统之间的相互作用模式（即支持或竞争）是至关重要的。
已知的内容：先前关于正常衰老过程中语言产生的研究主要集中在老年人口语表现的不同维度上，例如流畅性、词汇丰富度和语法复杂性，忽略了这些维度之间的复杂联系。然而，研究这些联系对于深入了解成年后期的语言产生至关重要，因为后者是一个由相互关联的组成部分构成的系统。此外，现有的研究大多将老年人视为同质群体，将他们的语言使用与年轻人进行比较。这种方法缺乏依据，因为老年人在不同衰老阶段的语言使用存在很大差异。
本文添加的内容：本研究揭示了正常衰老过程中语言产生的动态性质。老年人的口头叙述的不同维度或子系统（例如发音速度、不流畅率、句法复杂性）不仅会随着年龄的增长而变化，而且这些子系统相互作用的方式也会随着年龄的增长而演变，导致衰老过程中口语产生的状态发生变化。更具体地说，我们的研究提供了证据表明，老年人口头叙述的子系统之间的相互作用主要从早期阶段的支持关系转变为后期阶段的竞争关系。
潜在或实际的临床意义：本研究建议使用与语言表现的不同方面相关的多个语言指标来评估老年人的口语产生。这一点通过观察到老年人的口头叙述的不同维度在不同的衰老阶段不断相互作用得到强调，因此仅关注语言表现的一个维度往往会导致不准确或误导性的结果。此外，不同语言表现维度之间的相互作用模式（即支持或竞争）可能反映了老年人协调和控制注意力资源的能力，因此在评估老年人的语言表现时应予以考虑。
