Evaluating discourse production provides an effective means of assessing the language competence of persons with aphasia (PWA) in naturalistic and ecologically valid communication contexts. Existing research on PWA discourse has focused on discrete linguistic measures such as sample length or type-token ratios. To provide a holistic view of the interconnections of linguistic entities in PWA discourse, this study compared the lexical networks of discourse produced by PWA with those by healthy controls. At the macro level, PWA networks showed a smaller size and diameter but higher density compared to those of healthy controls. In addition, networks of both groups showed small-world characteristics. However, the degree of small-worldness was lower for the networks of PWA compared to those of healthy controls. At the meso level, network modularity measures of healthy controls were larger than those of PWA in the story-narrative task. At the micro level, the degrees of nodes in the networks of both groups followed a power-law distribution, suggesting that their networks were scale-free. Our findings reveal that lexical networks of PWA discourse are constrained and less efficient but still retain some basic characteristics of typical language networks.

Keywords: Aphasic discourse; lexical networks; modularity; small-world networks.

评估话语生成为在自然和生态有效的沟通环境中评估失语症患者（PWA）的语言能力提供了有效的方法。现有关于PWA话语的研究主要集中在样本长度或类型-词形比等离散语言测量上。为了全面了解PWA话语中语言实体之间的相互联系，本研究将PWA产生的词汇网络与健康对照组的词汇网络进行了比较。在宏观层面上，PWA的网络规模和直径较小，但密度较高，相比之下，健康的对照组则不然。此外，两组的网络都表现出小世界特性。然而，与健康对照组相比，PWA网络的小世界程度较低。在中观层面，在叙事任务中，健康对照组的网络模块化度量大于PWA。在微观层面上，两组网络中的节点度均遵循幂律分布，表明其网络具有无标度特性。我们的研究结果揭示了PWA话语中的词汇网络受到限制且效率较低，但仍保留了一些典型语言网络的基本特征。

关键词：失语症话语；词汇网络；模块化；小世界网络。