Abstract
Background: Individuals with Parkinson’s disease (PD) may need to spend more mental and physical effort (i.e., cognitive workload) to maintain postural control. Pupillary response reflects cognitive workload during postural control tasks in healthy controls but has not been investigated as a measure of postural demand in PD.Objectives: To compare pupillary response during increased postural demand using vision occlusion and dual tasking between individuals with PD and healthy controls.Methods: Thirty-three individuals with PD and thirty-five healthy controls were recruited. The four conditions lasted 60 s and involved single balance task with eyes open; single balance task with eyes occluded; dual task with eyes open; dual task with eyes occluded. The dual task comprised the Auditory Stroop test. Pupillary response was recorded using an eye tracker. The balance was assessed by using a force plate. Two-way Repeated Measures ANOVA and LSD post-hoc tests were employed to compare pupillary response and Center of Pressure (CoP) displacement across the four conditions and between individuals with PD and healthy controls.Results: Pupillary response was higher in individuals with PD compared to healthy controls (p = 0.009) and increased with more challenging postural conditions in both groups (p < 0.001). The post-hoc analysis demonstrated increased pupillary response in the single balance eyes occluded (p < 0.001), dual task eyes open (p = 0.01), and dual task eyes occluded (p < 0.001) conditions compared to single task eyes open condition.Conclusion: Overall, the PD group had increased pupillary response with increased postural demand compared to the healthy controls. In the future, pupillary response can be a potential tool to understand the neurophysiological underpinnings of falls risk in the PD population.
Highlights
Falls are a common problem for individuals with Parkinson’s disease (PD)
The post-hoc analysis demonstrated that pupillary response was significantly larger in the single balance eyes occluded (p < 0.001), dual task eyes open (p = 0.01), and dual task eyes occluded (p < 0.001) conditions compared to single task eyes open condition
There was a trend in the interaction effect of group × condition (p = 0.06), suggesting cognitive workload as a result of postural demand manifests differently in participants with PD compared to healthy controls (Supplementary Figure S1)
Summary
Falls are a common problem for individuals with Parkinson’s disease (PD). A fall is defined as an event in which an individual comes to rest involuntarily on a lower surface, such as the ground or floor (Kellogg, 1987). Studies have shown that fallers with and without PD exhibit increased prefrontal hemodynamic activation while performing walking and cognitive tasks at the same time (Maidan et al, 2016; Verghese et al, 2017). This increased hemodynamic activation is associated with performance on executive tasks (Ranchet et al, 2020). Studies have shown that individuals who have lower cognitive scores on executive function and attention tasks are more likely to fall up to three times than those with higher cognitive scores (Herman et al, 2010).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
