Physical activity as a mediator of anxiety and cognitive functioning in Parkinson's disease

Abstract

IntroductionIndividuals with Parkinson's disease (PD) are at increased risk of developing anxiety, cognitive decline, and reduced physical activity. Although anxiety is a risk factor for cognitive decline, the mechanisms underlying the relationship are unclear. The present study assessed if the relationship between cognition and anxiety symptoms is mediated by physical activity in a sample of individuals with PD followed for up to five years. MethodsParticipants (N = 487) were individuals newly diagnosed with Parkinson's disease followed by the Parkinson's Progression Marker Initiative (PPMI). Participants completed a neuropsychological battery and questionnaires of anxiety and physical activity. Structural equation models examined both the between-person and within-person effects of anxiety and cognition mediated through physical activity. ResultsAnalyses revealed a significant direct effect of anxiety predicting cognitive functioning. Additionally, there was a significant indirect within-person effect; meaning that individuals who became more anxious over time, they also reported becoming less physically active, which was subsequently associated with longitudinal declines in cognitive functioning. DiscussionFindings suggest that worsening anxiety early in the course of PD may be a risk factor for reduced participation in physical activities and subsequent cognitive decline.