External vs Internal-triggered Augmented-reality Visual Cues to Treat Freezing of Gait

Postural instability, freezing-of-gait (FOG), and falls are among the greatest unmet needs in Parkinson disease (PD). FOG eventually affects more than half of people with PD, and is notoriously difficult to treat pharmacologically or via deep brain stimulation. Visual cues do improve gait freezing, but their efficacy and adoption is limited because they are not practical to use in all real-world situations. There is a need for a cueing technique that is on-demand and discreet - only perceptible to the patient. Fortunately, recent technological advances in augmented-reality (AR) enable such an approach. In this study, state-of-the-art AR glasses will be used to project digital cues that are only visible to the wearer, to determine if they can improve FOG. 36 individuals with PD and FOG will be recruited to perform an obstacle-course gait task under six cue conditions: no cue, conventional cue, constant-on AR, patient-hand-triggered AR (turns on when patient clicks button), patient-eye-triggered AR (turns on when looking down), and examiner-triggered AR. The AR cue is a set of images that appear on the floor at a patient's feet, mimicking floor lines. Gait performance will be captured on video and via body-worn wireless sensors that detect how each limb is moving. The investigators will determine whether individuals are cue-able with conventional visual cues, whether intermittent cues outperform constant-on cues, and whether cues triggered by an examiner outperform cues triggered by patients themselves.