Portable Mixed Reality-based Platform for Assessment of Progress in Multisensory Rehabilitation Strategies Post-TBI

The goal of this comparative pilot study is to provide evidence that Praxis, a portable testbed with low-cost wearable sensors and a mixed reality environment, can deliver effective multisensory rehabilitation exercises with military face-validity in a military service member (SM) population after mild Traumatic Brain Injury (mTBI).

The main questions this comparative pilot study aims to answer are:

* Can the Praxis testbed provide feasible/acceptable 4-week multisensory rehabilitation for SMs with post-acute mTBI?
* Can Praxis detect and influence measurable changes in readiness performance during mTBI recovery?

Fifteen SMs with post-acute mTBI from the Center for the Intrepid's Special Operations Performance and Recovery (SPaR) Program will participate in the multisensory vestibular rehabilitation regimen. These SMs will go through 4 weeks of multisensory vestibular rehabilitation including:

* gaze stabilization
* dual-task balance training
* spatial navigation
* agility training

Data from another fifteen SMs, who will not go through the multisensory rehabilitation regimen and will receive supervised cardiovascular exercise, will be used as the control group.

Researchers will compare the Praxis and Control group to determine if the Praxis group shows improvement over the control group with respect to the military-relevant behavioral performance outcomes and patient-reported symptom scores after the end of the rehabilitation.

This study considers Praxis: a portable testbed with low-cost wearable sensors and a mixed reality environment to deliver effective multisensory rehabilitation exercises with military face-validity. Through a small comparative pilot study, the investigators plan to provide evidence for future multi-center randomized trials (MCRTs) to show that progress in these multisensory exercises correlates with established military readiness assessments; and that the improvements in functional performance in response to multisensory rehabilitation strategies is associated with changes in brain activity.

In preparation for an MCRT, the investigators will conduct a pilot study to examine and settle the issues of feasibility and effectiveness of protocol implementation in accordance with best practices. In this study, we:

* deliver a well-defined rehabilitation strategy via the Praxis system to the enable the patient to practice challenging rehabilitation tasks,
* assess changes in neurophysiological activity via resting state functional magnetic resonance imaging (rs-fMRI) over time in relation to the intensity of the rehabilitation strategy, and
* assess sensitive behavioral outcome measures that monitor the SM's functional gains over time via a battery of military-relevant tasks.

Fifteen SMs with post-acute mTBI from the Center for the Intrepid's Special Operations Performance and Recovery (SPaR) Program will participate in the multisensory vestibular rehabilitation regimen. These SMs will go through 4 weeks of multisensory vestibular rehabilitation:

* gaze stabilization
* dual-task balance training
* spatial navigation
* agility training

Data from another fifteen SMs, who will not go through the multisensory rehabilitation regimen and will receive supervised cardiovascular exercise, will be used as the control group.

The first purposes of this study are to demonstrate the feasibility of obtaining a representative sample of SMs with and without vestibular/ocular impairments post-mTBI in a Special Operations population; determine whether the data is collected reliably; and establish compliance with the protocol in the 4-week study timeline. The primary endpoints for this study are feasibility/acceptability of the 4-week multisensory rehabilitation for SMs with post-acute mTBI as determined by compliance to daily rehabilitation doses as verified by the VestAid software and acceptability measured by the System Usability Scale (SUS) with success thresholds set at 80% or more of the target population completing all the doses and an average total score of 68 or above on the SUS assessment.

The second purpose of this study is to determine the average values and variations of the behavioral outcome measures before and after multisensory rehabilitation delivered by Praxis, as well as the changes in neurophysiological activity, and the correlation between the two. The investigators will use this information to determine the sample size required for a future, larger multicenter study.

The investigators aim to evaluate the effect size relating the implicated functional changes to recovery over the 4-week rehabilitation period in the military population under study. The secondary endpoints of this pilot study will comprise preliminary statistical insights into the ability of Praxis to detect and influence measurable changes in readiness performance during mTBI recovery. The collected metrics include longitudinal Praxis compliance score, pre- and post- behavioral outcome measurements from the readiness battery, and patient-perceived disability questionnaires. Between-group analyses will be conducted to determine the effect size of the Praxis protocol on both the military-relevant behavioral outcomes as well as the patient-reported symptom scores. Within the Praxis group, the investigators will perform an exploratory analysis to examine the correlations between the military-relevant behavioral outcome scores, Praxis compliance scores, and previously implicated objective neurophysiological measures.

Eligibility Criteria:
Inclusion Criteria for Praxis Group:

* Participating in the SPaR Program
* 18-50 years old
* Have a self-reported or clinician-confirmed mTBI
* Have continued complaints of dizziness/imbalance
* Are right-handed as determined by the Edinburgh Handedness Inventory-Short Form

Inclusion Criteria for Control Group:

* Participating in the SPaR Program
* 18-50 years old
* No complaints of dizziness/imbalance

Exclusion Criteria:

* Having impaired mental capacity (e.g., altered capacity due to administration of any mind-altering substances or stress/life situations)
* Displaying behavior that would significantly interfere with validity of data collection or safety during the study
* Reporting significant pain during the evaluation (7/10 by patient subjective report)
* Being pregnant (balance considerations)
* Being unable to abstain from the use of alcohol and medications that might impair participant's balance or cerebral blood flow for 24 hours in advance of testing
* Being mixed or left-handed as determined by the Edinburgh Handedness Inventory-Short Form for the Praxis group undergoing rs-fMRI.