Using the Modified Vestibular/Ocular Motor Screening Tool to Identify Blast Exposure Effects in Military Service...

Military service members training with heavy weapons systems are exposed to low-level blast (LLB) overpressure, sometimes resulting in acute symptoms similar to mild traumatic brain injury (mTBI). There is a need for a quick and effective screening tool to identify early deficits and changes associated with blast exposure and minimizing potential ensuing effects. Recently, researchers developed the modified Vestibular/Ocular Motor Screening (mVOMS), designed to assess signs and symptoms of mTBI. modified Vestibular/Ocular Motor Screening consists of four physical movement conditions: smooth pursuits, horizontal saccades, horizontal vestibular-ocular reflex, and visual motion sensitivity to capture the provocation of the vestibular system (headache, dizziness, nausea, fogginess). After completing each activity, service members were asked whether the symptoms were present or absent. Modified Vestibular/Ocular Motor Screening offers a practical solution as it can be administered in approximately 2 minutes and is 85% accurate in identifying mTBI. Similarly, military settings, where time is often constrained in addressing potential mTBI can benefit from the efficiency and reliability of mVOMS, making it well-suited for training settings; however, the use of mVOMS to detect acute blast exposure effects in service members has not been explored, which was the primary purpose of this study. A secondary purpose was to explore the relationship between mVOMS and self-reported mTBI symptoms without provocation by physical motion, as well as eye-tracking.

This was a prospective cohort study design involving 42 male military personnel training with mortar systems and 15 male, healthy, unexposed controls. Participants reported demographics and over three separate visits, a self-reported symptoms questionnaire, mVOMS, and smooth pursuit eye tracking assessment. Independent samples t-tests and chi-square analyses, along with Pearson's and rank-biserial correlations, compared demographic and outcome variables between exposed and control groups from the three visits, including individual measures of blast exposure magnitude. A series of receiver operating characteristic (ROC) curves with area under the curve (AUC) were used to evaluate the accuracy of mVOMS, mTBI symptoms, and eye tracking to identify exposed from control groups. This study has been approved by the Walter Reed Army Institute of Research Institutional Review Board.

Participants' mean age was 25 ± 3.42 years with mean duration of service 4 ± 2.43 years. Service members exposed to blast reported more symptoms after performing the mVOMS physical movement challenges. The discriminatory power of the change from pre-exposure in mVOMS (AUC = 0.72) was comparable with the change in self-reported symptoms. In contrast to the change from pre-exposure, post-exposure single timepoint evaluation revealed mVOMS is superior (AUC = 0.70) compared to self-reported symptoms (AUC = 0.51). Modified Vestibular/Ocular Motor Screening was also positively correlated with blast exposure measures suggesting that increasing blast exposure levels are associated with increasing mVOMS scores.

These results demonstrate that mVOMS in individuals exposed to LLB elicits a response that may be more sensitive than self-report alone. Our data suggests that mVOMS may be useful to screen for mTBI symptomology in service members following blast exposure when administered as a single timepoint test, as it is quick, simple to interpret, and requires minimal training to administer.