A US study of female high school soccer players suggests that a neck collar may help protect the brain from head impacts over the course of a competitive soccer season.
“In sports, there’s a heavy focus on single big blows to the head that might lead to what is subjectively described as a ‘concussion,'” said Dr Greg Myer, director of sports medicine research at Cincinnati Children’s and lead author of the study. “What we really wanted to look at now is the cumulative effect of head impact exposure over an entire season. Evidence indicates that cumulative load of head impacts is potentially more concerning than that one single blow.”
The neck collar device, called a Q-Collar, is designed to press gently on the jugular vein to slow blood outflow, increasing the brain’s blood volume during competitive play. The resulting effect is blood filling the brain vessel (like an airbag) to help the brain fit tighter within the skull cavity, reducing the energy absorbed by the brain during collisions.
The study focused on cumulative sub-concussive impacts to the head that change the white matter structure of the brain. In soccer, that can come from a head ball to a collision with another player to a hard fall. “White matter is essentially structural pathways that connect all the information/signal processing centres of the brain that support normal function,” said Myer.
Myer and his colleagues studied 46 female high school soccer players. Twenty-four of them wore a Q-Collar. All 46 athletes underwent neuroimaging at up to three points in time over a six-month period. This included the 3-month soccer season and 3-month post season rest period, with no exposure to head impacts. Head impacts were tracked using accelerometers – a computer chip – placed behind the left ear during practice and games.
Neuroimaging analysis revealed significant white-matter changes from pre- to post-season in those who didn’t wear the collar. No significant changes were found in those who did wear the collar, despite a similar number and magnitude of head impacts.
Imaging conducted three months after the end of the soccer season showed that white matter changes in the non-collar group had either partially resolved or tracked back to normal.
“Certainly, we know the benefits of playing soccer in female athletes far outweigh the risks that we are seeing and that’s an important message we have to take away from this study,” said Myer.
Previous studies involving the Q-Collar looked at male hockey and football players and also showed significant protective effect from repetitive sub-concussive head impacts.
“This could be a paradigm shift in how we study the brain and protect the brain internally from head impact exposure,” said Myer. “We need to continue to do larger studies with various populations and as we move forward with more research we will know more on how effective this approach can be to protect the brain.”
Purpose: To (1) quantify white matter (WM) alterations in female high school athletes during a soccer season and characterise the potential for normalisation during the off-season rest period, (2) determine the association between WM alterations and exposure to repetitive subconcussive head impacts, and (3) evaluate the efficacy of a jugular vein compression collar to prevent WM alterations associated with head impact exposure.
Methods: Diffusion tensor imaging (DTI) data were prospectively collected from high school female soccer participants (14–18 years) at up to three time points over 9 months. Head impacts were monitored using accelerometers during all practices and games. Participants were assigned to a collar (n=24) or non-collar group (n=22). The Tract-Based Spatial Statistics approach was used in the analysis of within-group longitudinal change and between-group comparisons.
Results: DTI analyses revealed significant pre-season to post-season WM changes in the non-collar group in mean diffusivity (2.83%±2.46%), axial diffusivity (2.58%±2.34%) and radial diffusivity (3.52%±2.60%), but there was no significant change in the collar group despite similar head impact exposure. Significant correlation was found between head impact exposure and pre-season to post-season DTI changes in the non-collar group. WM changes in the non-collar group partially resolved at 3 months off-season follow-up.
Discussion: Microstructural changes in WM occurred during a season of female high school soccer among athletes who did not wear the collar device. In comparison, there were no changes in players who wore the collar, suggesting a potential prophylactic effect of the collar device in preventing changes associated with repetitive head impacts. In those without collar use, the microstructural changes showed a reversal towards normal over time in the off-season follow-up period.
Gregory D Myer, Kim Barber Foss, Staci Thomas, Ryan Galloway, Christopher A DiCesare, Jonathan Dudley, Brooke Gadd, James Leach, David Smith, Paul Gubanich, William P Meehan, Mekibib Altaye, Philip Lavin, Weihong Yuan