An experimental device was found to attenuate structural and functional brain changes in high school hockey players who were exposed to head impacts during their competitive season.
The results of a prospective randomized controlled trial were presented at the American College of Sports Medicine Annual Meeting on June 2, 2016. “While helmets have long been the mainstay of brain trauma prevention and are excellent at preventing fractures and lacerations, they cannot always prevent brain injury,” says the study’s lead author, Gregory Myer, PhD, a sports medicine researcher at the Cincinnati Children’s Hospital.
Designed to complement a helmet, the device works to reduce brain movement within the cranial cavity during a head impact. The movement, often referred to as brain slosh, damages both surface and deep structures of the brain. Retention of blood in venous sinuses of the brain has been shown to mitigate brain slosh in vivo. To translate these findings to the sports setting, developers of the technology designed a collar that curves around the neck and slightly presses on the jugular vein bilaterally. In a proof-of-concept study, magnetic resonance venography was performed to demonstrate a 1- to 2-ml increase in the cerebral blood volume in people wearing the collar.1
In the presented study, high school hockey players (n=14) were randomized to wearing the collar (n=7); all players wore a helmet and an accelerometer for head impact surveillance.2 Outcomes of the study – structural and functional changes in the brain – were measured before and during the hockey season.
Diffusion tensor imaging (DTI) was used as a measure of structural integrity of the white matter. DTI measures associated with disruption of white matter microstructure (mean and radial diffusivity) increased significantly in the non-collar group from preseason to midseason in several brain regions: the corpus callosum, corona radiata, and internal/external capsule (P<0.05). In players wearing the collar, these measures did not change from the pre-season level. The second outcome of the study, brain function, was assessed with electroencephalography followed by Brain Network Activation (BNA) analysis (ElMindA, Herzliya, Israel). From pre- to mid-season, BNA scores changed significantly greater in the non-collar group, compared to the collar group (P=0.007). In the non-collar group, a correlation of accumulated G forces, which represent a measure of head impact, and the change in the BNA scores was observed (P=0.023). Supporting the validity of the changes in the outcomes was a strong association between the changes in brain structural integrity and in brain network function (P<0.05).
“While these findings point at an exciting possibility that the collar protects both structure and function of the brain, they have to be interpreted cautiously,” Myer warned. First, it is unclear whether observed change in brain function is pathological or related to structural changes. Also, the study was not designed to evaluate concussion, nor did the athletes have concussion symptoms at post-season follow-up, hence the role of the collar in preventing concussion is still unproven. However, Myer noted, “the potential to prevent brain alterations in response to the everyday hit or sub-concussive blows might be the most exciting implications of the current study.”
Safety data collected to date are favorable. “That is not surprising considering that a similar back-up of the blood in the brain lasts for at least 8 hours daily, during sleep or while lying down,” says Myer. He, however, underscored the importance of formal safety studies before and after approval of the technology.
Funding for the collar trial was provided by Q30 Sports Science, LLC, which is the developer of the collar. Gregory Myer has no financial interest in and is not affiliated with Q30 Sports Science. Financial support for the research aimed at prevention of concussion was also provided by The Heidt Family Foundation.
1. These data were presented by James Leach, MD, at the American Academy of Neurology annual meeting in 2014.
2. Myer GD, et al. The effects of external jugular compression applied during head impact exposure on longitudinal changes in brain neuroanatomical and neurophysiological biomarkers: a preliminary investigation. Front Neurol. [article in press] 2016.