Cognitive Flexibility is Critical for Postural Control in People with Parkinson Disease

Background: Postural instability is a common and debilitating symptom in Parkinson disease (PD) that impacts daily functioning and quality of life. Executive function, a domain of cognitive functioning, has been associated with postural control. Impairments in executive function, including cognitive flexibility, may lead to postural instability in individuals with PD. This study aimed to examine the relationship between postural instability and cognitive flexibility in PD. While broader executive function domains were explored, cognitive flexibility was hypothesized to be particularly relevant to postural instability. Cognitive assessments were selected to specifically evaluate this domain alongside other key aspects of executive function. Objective: To examine the relationship between postural instability and cognitive flexibility in PD. Methods: Thirty-six participants, including 12 people with PD who had postural instability (PDPI+), 12 people with PD without postural instability (PDPI-), and 12 age-matched healthy controls participated. Cognitive assessments were performed using the MoCA and the NIH Toolbox-Cognition Battery. A Clinical Balance Systems (CBS) score was also calculated during clinical evaluation. Results and Discussion: Data analysis included ANOVA, ANCOVA, Pearson correlation, and partial correlation analyses. The PDPI+ group exhibited significant cognitive deficits compared to healthy controls, particularly in cognitive flexibility. Cognitive flexibility emerged as a critical factor linked to postural instability. In all participants who had PD, strong negative correlations were observed between CBS scores and cognitive flexibility, suggesting a robust connection between cognitive flexibility and postural control. These associations remained significant even after controlling for age, disease duration, and levodopa equivalent daily dose. Conclusions: Our findings underscore the significant relationship between cognitive flexibility and postural control in individuals with PD. The results highlight the potential role of targeted interventions to improve cognitive flexibility and, consequently, postural stability in people with PD who have postural instability.