Martin Nadine, Kohen Francine, Kalinyak-Fliszar Michelene, Soveri Anna, Laine Matti
Temple University, Philadelphia, USA.
Aphasiology. 2012 Mar;26(3-4):462-493. doi: 10.1080/02687038.2011.619516. Epub 2012 Feb 22.
Language performance in aphasia can vary depending on several variables such as stimulus characteristics and task demands. This study focuses on the degree of verbal working memory (WM) load inherent in the language task and how this variable affects language performance by individuals with aphasia. AIMS: The first aim was to identify the effects of increased verbal WM load on the performance of judgments of semantic similarity (synonymy) and phonological similarity (rhyming). The second aim was to determine if any of the following abilities could modulate the verbal WM load effect: semantic or phonological access, semantic or phonological short-term memory (STM) and any of the following executive processing abilities: inhibition, verbal WM updating, and set shifting. METHOD AND PROCEDURES: Thirty-one individuals with aphasia and 11 controls participated in this study. They were administered a synonymy judgment task and a rhyming judgment task under high and low verbal WM load conditions that were compared to each other. In a second set of analyses, multiple regression was used to identify which factors (as noted above) modulated the verbal WM load effect. OUTCOME AND RESULTS: For participants with aphasia, increased verbal WM load significantly reduced accuracy of performance on synonymy and rhyming judgments. Better performance in the low verbal WM load conditions was evident even after correcting for chance. The synonymy task included concrete and abstract word triplets. When these were examined separately, the verbal WM load effect was significant for the abstract words, but not the concrete words. The same pattern was observed in the performance of the control participants. Additionally, the second set of analyses revealed that semantic STM and one executive function, inhibition ability, emerged as the strongest predictors of the verbal WM load effect in these judgment tasks for individuals with aphasia. CONCLUSIONS: The results of this study have important implications for diagnosis and treatment of aphasia. As the roles of verbal STM capacity, executive functions and verbal WM load in language processing are better understood, measurements of these variables can be incorporated into our diagnostic protocols. Moreover, if cognitive abilities such as STM and executive functions support language processing and their impairment adversely affects language function, treating them directly in the context of language tasks should translate into improved language function.
失语症患者的语言表现会因多种变量而有所不同，如刺激特征和任务要求。本研究聚焦于语言任务中固有的言语工作记忆（WM）负荷程度，以及该变量如何影响失语症患者的语言表现。
第一个目的是确定言语WM负荷增加对语义相似性（同义词）判断和语音相似性（押韵）判断表现的影响。第二个目的是确定以下任何一种能力是否能调节言语WM负荷效应：语义或语音通达、语义或语音短期记忆（STM）以及以下任何一种执行加工能力：抑制、言语WM更新和任务转换。
31名失语症患者和11名对照组参与者参与了本研究。他们在高言语WM负荷条件和低言语WM负荷条件下分别接受了同义词判断任务和押韵判断任务，并对这两种条件进行了相互比较。在第二组分析中，使用多元回归来确定哪些因素（如上所述）调节了言语WM负荷效应。
对于失语症患者，言语WM负荷增加显著降低了同义词和押韵判断的表现准确性。即使校正了随机因素，在低言语WM负荷条件下的表现仍更优。同义词任务包括具体词和抽象词三元组。当分别对这些进行检查时，言语WM负荷效应在抽象词中显著，但在具体词中不显著。对照组参与者的表现也观察到了相同的模式。此外，第二组分析表明，语义STM和一种执行功能，即抑制能力，是这些判断任务中失语症患者言语WM负荷效应的最强预测因素。
本研究结果对失语症的诊断和治疗具有重要意义。随着言语STM容量、执行功能和言语WM负荷在语言加工中的作用得到更好的理解，对这些变量的测量可以纳入我们的诊断方案。此外，如果诸如STM和执行功能等认知能力支持语言加工，且它们的损伤对语言功能产生不利影响，那么在语言任务的背景下直接对其进行治疗应能转化为语言功能的改善。
