Dr. W. Geoffrey Wright, director of neuromotor science programs and associate professor in the department of physical therapy at Temple University College of Public Health, published the results of a study exploring postural control and stress reactivity in active duty coast guard personnel in the March/April supplement to Military Medicine.
For the study, researchers used a custom-designed virtual reality-based device in assess stability, startle response and neurocognitive performance in coast guard members who previously experienced mild traumatic brain injury (mTBI).
The 36 participants had no deployment-limiting medical condition but had a history of brain injury, including 39 percent of participants who had a previous mTBI and five participants who had experienced more than one. Participants were recruited by experimenters at coast guard boat stations at Port Canaveral and Port Lauderdale in Florida. The mTBI came from a variety of sources: blasts, falls, sports and vehicle injuries, and other blunt force traumas. The study built on Wright’s previous work with the Virtual Environment TBI Screen (VETS) in Temple’s Motion-Action-Perception lab.
Researchers found that the number of mTBI incidents had a significant effect on posture, and lifetime mTBI was associated with a suppressed acoustic startle response; neurocognitive performance did not seem to be affected. Though the ability to maintain balance on a stable surface (with eyes open, closed, and while viewing scene) and on a foam surface (with eyes open and closed) were unaffected, participants with multiple past TBIs showed deficits in the most demanding task of maintaining balance on foam while viewing a moving scene.
In addition, the magnitude of response to audio stimuli was reduced in those with a history of mTBI, despite those participants self-reporting no symptoms.
“In other populations, the two deficits – startle reactivity and balance on unstable surfaces with conflicting visual stimuli – may not only go unnoticed but may be easily dismissed as having little functional impact,” Dr. Wright wrote. “Yet, the operational demands confronting coast guard personnel may at times draw on such otherwise subtle capabilities for mission success.”
Read more from Temple’s department of physical therapy.