38 - Measuring the Effects of Mild Traumatic Brain Injury and Post-traumatic symptoms in Veteran and Civilian Populations using Novel Virtual Reality (VR) Technology
Graduate student Neuromotor Sciences Program, Temple University Philadelphia, Pennsylvania
Abstract Text: Background &
Objective: The long-term effects of mild traumatic brain injury (mTBI) are a health concern for sports and recreation in civilian populations, but military service members have exposure to risks that can increase likelihood of having a history of mTBI and/or comorbid PTSD. Following a concussive injury, symptoms will often resolve within 7-10 days, but subacute signs may persist for months or years following the initial injury. For those with a military service record, there is also increased risk for concurrent psychological impairment with signs and symptoms that may not be easily dissociable from those related to mTBI. Some of these include headache, dizziness, balance, vestibular, and oculomotor function. Current assessments of these sensorimotor functions are limited by their cumbersome footprint, accessibility, prohibitive cost, objectivity and reliability. The current project focuses on creating and validating objective assessments of balance and visual-vestibular function which also address the limitations of currently available assessments.
Study
Design: An intermediate analysis of a preliminary sample of civilians (N= 42) at Temple University and Veterans (n= 6) at the Philadelphia VA Medical Center, included 18 individuals with and 30 without of a history of mTBI (inclusion criterion: time-since-injury must be greater than 6 months). They were assessed using validated criterion-measures and novel VR-goggle-based measures. This included a balance assessment (Neurocom Sensory Organizational Test – SOT, and the VR-Sensory Integration in Balance – VRSIB), convergence insufficiency tests (manual Near Point Conversion – NPC, and VR-NPC), and a vestibulo-ocular reflex (VOR) test (Gaze Stabilization Test – VR-GST). Pearson correlations were performed to establish criterion validity, and independent means t-tests were performed to establish construct validity.
Results: The balance scores on comparable conditions of the VR-SIB showed highly significant correlations with the criterion-measure SOT with r=0.300-0.672 (p < 0.01). Neither device showed significant sensitivity to mTBI history. The VR test of convergence insufficiency was significantly correlated with the criterion-measure NPC test with r=0.371 (p=0.009). Neither assessment showed significant sensitivity to mTBI history. The VR test of vestibulo-ocular reflex (VOR) (VR-GST) showed a non-significant trend differentiating by veteran status (p=0.108), but was not sensitive to history of concussion.
Conclusion: This project attempts to address a gap in current clinical balance and vestibulo-ocular assessments that are necessary for identifying possible long-lasting signs following mTBI and/or PTSD. While the project is ongoing, we have begun to show criterion-validity of novel portable, VR-based assessments, which when complete can provide easy-to-use objective means for quick clinical evaluation of veterans or athletes with a history of mTBI. Although we have tested 18 individuals with a history of mTBI, all were asymptomatic, and neither the criterion measures, nor the novel measures have detected lingering deficits. A limitation of the study to date, is that construct validation based on asymptomatic participants requires a larger sample size. Thus, the intermediate nature of this partial and underpowered sample (so far n=1 for PTSD). Data collection is ongoing with less than 1/3rd of the proposed sample collected. The end objective is to determine the most sensitive metrics and use them for a quick comprehensive predictive screening tool to help guide treatment of mTBI and PTSD.
