Validating a Seated Virtual Reality Threat Paradigm for Inducing Anxiety and Freezing of Gait in Parkinson's Disease.

Background Although prior research has established that freezing of gait (FOG) in Parkinson's disease (PD) is associated with anxiety, only one study to date has directly manipulated anxiety levels to induce FOG. Objective The current study aimed to replicate these previous findings and evaluate whether a seated version of a 'threat' virtual reality (VR) paradigm could induce anxiety and provoke FOG. Methods Twenty-four PD patients with FOG were assessed across various threat conditions in both a walking VR paradigm (Experiment 1) and a seated VR paradigm (Experiment 2). Both paradigms manipulated the height (i.e., elevated vs ground) and width (wide vs narrow) of the planks participants were instructed to walk across. Results Across both experiments, the Elevated + Narrow condition provoked significantly greater number of freezing episodes compared to all other conditions. Higher levels of self-reported anxiety were reported during the Elevated+Narrow condition compared to all other conditions in Experiment 1, and compared to the Ground condition in Experiment 2. Conclusion These findings confirm that anxiety contributes to FOG and validates the use of a seated VR threat paradigm for provoking anxiety-related freezing. This enables future studies to combine this paradigm with functional MRI to explore the neural correlates underlying the role of anxiety in FOG.