Tehran University of Medical Sciences Journal of Modern Rehabilitation 2538-385X 0 - 2026 02 02 1461 1461 EN Kiana Ghasrhamidi Rehabilitation Research Centre, Department of Speech Therapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran Arezoo Saffarian Rehabilitation Research Centre, Department of Speech Therapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran Reyhane Mohammadi Rehabilitation Research Centre, Department of Speech Therapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran Seyed Amir Hasan Habibi Department of Neurology, School of Medicine, Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran Nahid Jalilevand Rehabilitation Research Centre, Department of Speech Therapy, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran 2025 11 04 2026 02 01 Background: Parkinson's disease (PD) affects not only motor function but also cognition and language, including narrative discourse, which relies on linguistic processes and higher-order cognitive functions such as working memory and executive functions. So, the aim of this study was to investigate the relationship between narrative discourse features and cognitive functions in Persian-speaking PD patients. Material and Methods: In this cross-sectional study, 26 PD patients and 26 age, sex, and education-matched healthy controls participated. Cognitive performance was assessed using the Persian Montreal Cognitive Assessment (MoCA-P), digit span, Stroop, verbal fluency, and the Persian Cognitive Reserve Index (CRIq). Narrative discourse was evaluated using the Persian Narrative Discourse Test. Data were analyzed with the Mann-Whitney test and Spearman correlation. Results: In PD patients, syntactic complexity correlated positively with MoCA-P (p = 0.001, rₛ = 0.627), CRIq (p = 0.012, rₛ = 0.487), phonological verbal fluency (p = 0.032, rₛ = 0.420), and forward digit span (p = 0.015, rₛ = 0.472). Lexical cohesion correlated with MoCA-P (p = 0.012, rₛ = 0.484) and CRIq (p = 0.002, rₛ = 0.573), while conjunctive cohesion was associated with MoCA-P (p = 0.022, rₛ = 0.448) and semantic verbal fluency (fruits) (p = 0.041, rₛ = 0.404). Conclusions: The results of this study demonstrate that higher levels of global cognition, working memory, verbal fluency, and cognitive reserve are associated with increased syntactic complexity and enhanced lexical and conjunctive cohesion in the narrative discourse of patients with PD. These findings indicate that cognitive decline adversely affects narrative organization and structural integrity. https://jmr.tums.ac.ir/index.php/jmr/article/view/1461