The goal of this project is to evaluate the safety and preliminary effectiveness of utilizing a digital therapeutic, Dual-task Augmented Reality Treatment (DART) protocol, for the treatment of postural instability and gait dysfunction (PIGD) in individuals with PD with a previously implanted deep brain stimulator (DBS).

Multi-Modal Training in PD patients: In order to treat dual-task impairment (difficulty performing two tasks at once), multi-modal treatment (MMT) was designed to target PD-specific declines in the areas of cognitive function and gait and posture impairments. Briefly, MMT training consists of simultaneously training a motor and cognitive task. The motor aspect of MMT stresses high velocity, high amplitude training principles while the cognitive aspect stresses commonly impaired cognitive domains in PD such as attention and executive function. An example of an MMT task is marching while spelling words backwards.

Delivery of a Digital Therapeutic via Augmented Reality for the Treatment of PIGD: The MMT intervention is well-suited for integration into an augmented reality (AR) platform as it consists of the patient performing a series of cognitive and motor tasks simultaneously while the patient receives knowledge of performance and results from a therapist. The Microsoft HoloLens is an untethered, AR headset used in applications as broad as teaching anatomy, displaying fine art and gaming. With AR, the user maintains contact with the physical world and the people in it. The HoloLens uses AR technology to place holograms, objects made entirely of projected light, into the user's physical environment; hence creating a first-person mixed reality environment. These holograms can be viewed from different angles and distances, can be two-dimensional or three-dimensional, can appear life-like, can move, be shaped, and change according to interaction with users' or the physical environment in which they are projected, depending on the programming. The MMT was previously developed for the Dual-task Augmented Reality Treatment (DART), which delivers MMT training on a head-mounted AR display. The DART platform was successfully piloted in 50 individuals with PD who did not have DBS (IRB # 20-207). The results of the project indicate that DART is an effective method of training for individuals with PD. The goal is to expand the impact of that project through the investigation of DART in individuals with PD who have previously undergone DBS surgery.

Inclusion Criteria:

• Adult with a diagnosis of idiopathic PD
• History of deep brain stimulator placement for treatment of PD
• Ability to ambulate > 10 minutes continuously without an assistive device

Exclusion Criteria:

• Medical diagnosis of dementia or any neurocognitive impairment that compromises the ability to provide informed consent

  ->2 errors on the Short Portable Mental Status Questionnaire

• Musculoskeletal or cardiopulmonary issue that limits one's ability to engage in exercise

• Neurological disease other than Parkinson's disease that impacts motor or cognitive function

Adverse events were collected during active study participation dates. The study intervention from baseline testing to end of testing was an 8-week period, not to exceed 10-weeks. Participants were asked at each session whether any adverse events occurred since the previous session.