Although limited and reduced connected speech production is one, if not the most, prominent feature of aphasia, few studies have examined the properties of content words produced during discourse in aphasia, in comparison to the many investigations of single-word production. In this study, we used a distributional analysis approach to investigate the properties of content word production during discourse by 46 participants spanning a wide range of chronic poststroke aphasia and 20 neurotypical adults, using different stimuli that elicited three discourse genres (descriptive, narrative, and procedural). Initially, we inspected the discourse data with respect to the quantity of production, lexical–semantic diversity, and psycholinguistic features (frequency and imageability) of content words. Subsequently, we created a “lexical–semantic landscape,” which is sensitive to subtle changes and allowed us to evaluate the pattern of changes in discourse production across groups. Relative to neurotypical adults, all persons with aphasia (both fluent and nonfluent) showed significant reduction in the quantity and diversity of production, but the lexical–semantic complexity of word production directly mirrored neurotypical performance. Specifically, persons with aphasia produced the same rate of nouns/verbs, and their discourse samples covered the full range of word frequency and imageability, albeit with reduced word quantity. These findings provide novel evidence that, unlike in other disorders (e.g., semantic dementia), discourse production in poststroke aphasia has relatively preserved lexical–semantic complexity but demonstrates significantly compromised quantity of content word production. Voxel-wise lesion-symptom mapping using both univariate and multivariate approaches revealed left frontal regions particularly the pars opercularis, insular cortex, and central and frontal opercular cortices supporting word retrieval during connected speech, irrespective of their word class or lexical–semantic complexity.

虽然有限和减少的连接语音产生是失语症的一个（如果不是最显着的）显着特征，但与对单个词产生的许多调查相比，很少有研究检查失语症话语期间产生的实词的属性。在这项研究中，我们使用分布分析方法来调查 46 名参与者在话语过程中产生的内容词的属性，这些参与者跨越范围广泛的慢性卒中后失语症和 20 名神经型成人，使用不同的刺激引发了三种话语类型（描述性、叙述性和程序）。最初，我们检查了关于内容词的生产数量、词汇语义多样性和心理语言特征（频率和可形象性）的话语数据。随后，我们创建了一个“词汇-语义景观，”这对细微的变化很敏感，使我们能够评估跨群体话语生产的变化模式。相对于神经型成人，所有失语症患者（流利和不流利）都表现出生产的数量和多样性显着降低，但单词生产的词汇语义复杂性直接反映了神经型的表现。具体来说，失语症患者产生的名词/动词比例相同，他们的话语样本涵盖了词频和形象性的全部范围，尽管词量有所减少。这些发现提供了新的证据，表明与其他疾病（例如，语义痴呆）不同，中风后失语症的话语产生相对保留了词汇-语义复杂性，但表明内容词产生的数量显着受损。