Protection Against Potential Brain Injury During Competitive Football

Overview

Significant morbidity, mortality, and related costs are caused by traumatic brain injury (TBI). An externally-worn medical device that applies mild jugular compression according to the principle of the Queckenstedt Maneuver (the Device). Preliminary research suggests that the Device has the potential to reduce the likelihood of TBI. The currently developed collar has been approved for studies in humans and the results indicate safety for use during high demand and maximal exertion activities, This study will investigate the effectiveness of this device in high school athletes playing a collision sport such as football. The use of helmets during such a high-risk sport will allow for collision measurement devices to be embedded in the helmet and will not affect play or fit of equipment. Athletes participating in this study will be randomly assigned to one of two groups: 1) Device wearing during the season or 2) Non-device wearing during the season. The helmets of all participants will be outfitted with an accelerometer which will measure the magnitude of every impact to the head sustained by the athlete. Effectiveness of the device will be determined via differences in longitudinal brain imaging and functional testing following competitive football participation. A subset of athletes who report a diagnosed concussion will also receive additional brain neuroanatomical and neurophysiological testing within a week following the diagnosed concussive event. The purpose of the study is to monitor longitudinal changes in brain structure and function between the preseason and postseason, in a population of football playing athletes wearing the Device and compared to a similar population not wearing the device. Secondly, the purpose is to determine the protection of the device relative to amount and magnitude of sustained head impacts.

The Device has the promise of providing a novel mechanism for reducing or preventing the likelihood of TBI, and may be used in conjunction with other protective equipment. TBI is the leading cause of death in individuals under age 45. The cost of TBI in the U.S. is estimated at anywhere from $50 to $150 billion, annually. The January, 2008 New England Journal of Medicine reports, "Head and neck injuries, including severe brain trauma, have been reported in one quarter of service members who have been evacuated from Iraq and Afghanistan". The vast majority of these injuries have resulted from exposure to improvised explosive device (IED) blast waves. Head injuries, concussions and the resulting trauma have been in public discussion recently as the National Football League (NFL) deals with a lawsuit regarding head injuries by about one-third of living former NFL players. According to NASA, "The oscillation of a fluid caused by an external force, called sloshing, occurs in moving vehicles containing liquid masses, such as trucks, etc." This oscillation occurs when a vessel is only partially filled. It is hypothesized that the brain faces similar slosh energy absorption during external force impartation. Slosh permits external energies to be absorbed by the contents of a partially filled vessel or container by means of inelastic collisions. Tissues of differing densities can decelerate at different rates creating shear and cavitation. If the collisions between objects or molecules are elastic, the transfer of energies to those objects diminishes, minimizing the energies imparted by slosh. Woodpeckers, head ramming sheep and all mammals (including humans) have small, little known and misunderstood muscles in their necks called the omohyoid muscles. Highly G-tolerant creatures of the forest have utilized these muscles to gently restrict outflow of the internal jugular veins thereby "taking up" the excess compliance of the cranial space and ultimately protecting themselves from TBI like tiny "airbags" in a motor vehicle. Rat studies by have demonstrated that we can easily and safely facilitate this muscle's actions by a well-engineered gentle compression over those muscles. The medical Queckenstedt Maneuver devised to detect spinal cord compression, gently places pressure over the external jugular veins to increase cerebral spinal volume and pressure. In this maneuver, the veins are compressed while a lumbar puncture monitors the intracranial pressure. "Normally, the pressure rise to the higher 'plateau' level occurs instantly upon jugular compression to fall again equally fast upon release of the compression". This incredibly simple principle can be employed to protect soldiers and athletes from TBI by safely, and reversibly, increasing intracranial volume and pressure. The neck collar device is made of Outer collar - hytrel (thermoplastic elastomer), Inner collar - TPSiV (thermoplastic elastomer), metal insert (stainless steel), and is fitted to the neck to provide a comfortable and precise jugular compression that potentially mitigates cerebral slosh. Although the skull, blood, and brain are "almost incompressible," the vasculature tree of the cerebrum is quite reactive and compressible. As volume is added to the cranium, eventually the compensatory reserve volume is surpassed and the intracranial pressure increases slightly. Increasing cerebral blood volume by just 1-3% safely and reversibly reduces compliance of the cerebral vascular tree and diminishes absorption of slosh energies. Jugular compression increases cerebral blood volume almost instantaneously. As mentioned, this degree of increase has significantly mitigated slosh and TBI in laboratory animals and mimics the highly concussion resistant wild animals that are able to reflexively increase cerebral blood volume through natural jugular compression. A landmark article, published in the Journal of Neurosurgery, used a standard acceleration-deceleration impact laboratory model of mild TBI. The study showed a successful and marked reduction of axonal injury following Internal Jugular Vein (IJV) compression as indicated by immunohistochemical staining of Amyloid Precursor Proteins (APP). It is argued that IJV compression reduces slosh-mediated brain injury by increasing intracranial blood volume and reducing the compliance and potential for brain movement within the confines of the skull. The potential for such technique to mitigate both linear and rotational brain injury in humans by "internal protection" represents the most novel approach to mitigating TBI. The current project will be designed following a prospective longitudinal study design. All MRI scanning will be performed on a 3 Tesla Philips Achieva MRI scanner located in Imaging Research Center (IRC) in the Cincinnati Children's Hospital Research Foundation (CCHRF). Sedation will not be used for any of the test visits. The entire MRI series, including anatomical imaging, DTI, resting state fMRI, SWI, HARDI, ASL and BOLD will be completed in 65 minutes or less (see Table 1 for detailed specifications). All functional and neurocognitive testing will be performed at the Cincinnati Children's Hospital Human Performance Laboratory.