Characteristics of Verb Retrieval According to Hoehn and Yahr Stage in Idiopathic Parkinson's Disease Patients

Purpose The purpose of this study was to examine verb retrieval performance in idiopathic Parkinson’s disease (IPD) patients across different Hoehn and Yahr (H&Y) stages, focusing on response accuracy and reaction time for verbs varying in motor content. Methods Twenty-seven individuals diagnosed with IPD were grouped according to H&Y stages (1.5, 2.0, and 2.5). Participants completed a verbnaming task involving five high-motion and five low-motion Korean verbs. Results Significant differences were found in verb retrieval reaction time across H&Y stages, particularly between stages 1.5 and 2.5. While accuracy differences by motor content were not significant, reaction time tended to increase with higher H&Y stages, especially for high-motion verbs. Correlation analyses suggested that disease progression is associated with lower accuracy and longer response times, more notably in high-motion verbs. Conclusion Verb retrieval performance may decline as Parkinson’s disease progresses, with high-motion verbs showing greater sensitivity to motor and cognitive impairment. These findings underscore the potential link between motor symptoms and linguistic processing, although further studies are needed to confirm these patterns.