Verbal expressive language minimally affected in non-demented people living with amyotrophic lateral sclerosis

Objective: Language dysfunction is one of the most common cognitive impairments in amyotrophic lateral sclerosis (ALS). Although discourse capacities are essential for daily functioning, verbal expressive language has not been widely investigated in ALS. The existing research available suggests that discourse impairments are prevalent. This study investigates verbal expressive language in people living with ALS (plwALS) in contrast to healthy controls (HC).
Methods: 64 plwALS and 49 age, gender and education-matched healthy controls were ask to describe the Cookie Theft Picture Task. The recordings were analyzed for discourse productivity, discourse content, syntactic complexity, speech fluency and verb processing. We applied the Bayesian hypothesis-testing framework, incorporating the effects of dysarthria, cognitive impairment status (CIS), and premorbid crystalline verbal IQ.
Results: Compared to HC, plwALS only showed a single impairment: speech dysfluency. Discourse productivity, discourse content, syntactic complexity and verb processing were not impaired. Cognition and dysarthria exceeded the influence of verbal IQ for total words spoken and content density. Cognition alone seemed to explain dysfluency. Body-agent verbs were produced at even higher rates than other verb types. For the remaining outcomes, verbal IQ was the most decisive factor.
Conclusions: In contrast to existing research, our data demonstrates no discernible impairment in verbal expressive language in ALS. What our findings show to be decisive is accounting for the influence of dysarthria, cognitive impairment status, and verbal IQ as variables on spontaneous verbal expressive language. Minor impairments in verbal expressive language appear to be influenced to a greater degree by executive dysfunctioning and dysarthria than by language impairment.

研究目标：语言功能障碍是肌萎缩侧索硬化症（amyotrophic lateral sclerosis, ALS）最常见的认知障碍之一。尽管话语表达能力（discourse capacities）对日常功能至关重要，但针对肌萎缩侧索硬化症患者（people living with ALS, plwALS）的言语表达语言（verbal expressive language）功能的研究尚未得到广泛开展。现有相关研究表明，话语表达障碍（discourse impairments）在该群体中普遍存在。本研究旨在对比分析肌萎缩侧索硬化症患者与健康对照者（healthy controls, HC）的言语表达语言功能。

研究方法：本研究纳入64名肌萎缩侧索硬化症患者与49名在年龄、性别及教育程度上匹配的健康对照者，要求受试者完成“偷饼干图片任务（Cookie Theft Picture Task）”。对受试者的语音录音进行分析，涵盖话语产出量（discourse productivity）、话语内容（discourse content）、句法复杂度（syntactic complexity）、言语流畅性（speech fluency）及动词加工（verb processing）五大分析维度。本研究采用贝叶斯假设检验框架（Bayesian hypothesis-testing framework），同时纳入构音障碍（dysarthria）、认知障碍状态（cognitive impairment status, CIS）及病前晶体言语智商（premorbid crystalline verbal IQ）作为调节变量。

研究结果：与健康对照者相比，肌萎缩侧索硬化症患者仅表现出单一受损维度：言语流畅性障碍。话语产出量、话语内容、句法复杂度及动词加工能力均未出现显著受损。构音障碍与认知障碍状态对总话语字数及内容密度的影响程度超过言语智商。仅认知障碍状态可解释言语流畅性受损情况。躯体-施事动词（body-agent verbs）的产出率甚至高于其他动词类型。针对其余观测指标，言语智商是最具决定性的影响因素。

研究结论：与现有研究结论相悖，本研究数据表明肌萎缩侧索硬化症患者的言语表达语言功能无明显受损。本研究结果显示，构音障碍、认知障碍状态及言语智商作为影响自发言语表达语言的变量，是解释观测结果的核心要素。言语表达语言的轻微受损，似乎更多受执行功能障碍（executive dysfunctioning）与构音障碍的影响，而非语言本身的原发性受损。