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.

Inclusion Criteria:

• Clinical diagnosis of PD
• Presence of freezing of gait, defined as a score of ≥1 in MDS-UPDRS 2.13, or 3.11.
• Can walk without assistance, OFF meds, based on yes/no verbal response

Exclusion Criteria:

• Severity of gait impairment should not require dependency to walker or cane
• Concomitant conditions that may affect significantly the evaluation of balance or gait, including orthopedic, rheumatologic or other neurological diseases
• Contraindication to physical therapy
• Severe bilateral visual impairment
• Age < 21
• Diagnosis of dementia
• Not agreeable to having video taken of entire research visit

At time of publication, a point of contact individual on the study team will be identified. Third parties will be able to request access to de-identified data used to support the publication findings by application to the Cleveland Clinic IRB. A data use agreement will be put in place between the CCF Cleveland Clinic and this third party for approved use of the data.