Feasibility of using normobaric hypoxic stress in mTBI research

Abstract

Studies of mild traumatic brain injury (mTBI) recovery generally assess patients in unstressed conditions that permit compensation for impairments through increased effort expenditure. This possibility may explain why a subgroup of individuals report persistent mTBI symptoms yet perform normally on objective assessment. Accordingly, the development and utilization of stress paradigms may be effective for enhancing the sensitivity of mTBI assessment. Previous studies, discussed here, indirectly but plausibly support the use of normobaric hypoxia as a stressor in uncovering latent mTBI symptoms due to the overlapping symptomatology induced by both normobaric hypoxia and mTBI. Limited studies by our group and others further support this plausibility through proof-of-concept demonstrations that hypoxia reversibly induces disproportionately severe impairments of oculomotor, pupillometric, cognitive and autonomic function in mTBI individuals.

Normobaric Hypoxia with a Simple Saccade Task Reveals Latent Performance Deficits in Service Members Affected by Mild Traumatic Brain Injuries (mTBI)

“…We posit that concussed individuals with BRC above the FIT may have the capacity to overcome or compensate for a discernable deficit, but those with BRC below the FIT cannot. Recent work in our laboratory (Temme et al, 2013;Temme, St Onge, Bleiberg, 2016;Regan, Bleiberg, St. Onge, & Temme, 2017) and those of others (Astafiev et al, 2015;Maruta, Palacios, et al, 2016;Maruta, Spielman, et al, 2016) support the notion that in the presence of concussion, certain stresses, either psychological or physiological, can reduce BRC below the FIT threshold so that otherwise unmeasurable deficits become manifest.…”