On December 1, 2012 Jovan Belcher emptied nine bullets into his girlfriend before fatally shooting himself in the parking lot of Kansas City’s Arrowhead Stadium. Belcher was the linebacker for the Kansas City Chiefs. This was around the time when several former football players were suing the National Football League (NFL) for negligence and accusing the organization of failing to inform players of the link between concussions and long-term brain damage.

What is a concussion?

Concussion is a form of mild traumatic brain injury (TBI) resulting from a blow to the head. It can also be caused by a jolt to the body that causes the brain to bounce rapidly back and forth within the skull. In short, a concussion is a bruise to the brain either from a physical impact or sudden motion. Collisions during sports, motor vehicle accidents, falls, domestic violence and other forms of assault can result in a concussion.

How can we avoid concussions?

Our brain is a delicate mass of soft tissue. Two mechanisms have evolved to protect this mass of tissue that makes us who we are: 1) The brain floats in clear, nutrient-containing fluid (cerebrospinal fluid) that acts as a shock-absorber, and 2) The brain is encased within a bony skull for protection. It’s kind of like an egg where the precious yolk is surrounded by egg whites and protected by an outer shell.

To avoid damaging the yolk, it is important to prevent the egg shell from cracking. Wearing protective gear such as helmets ensures that the protective shell of our brain, the skull, remains unharmed during contact sports, bike riding, etc. But what happens when the protector becomes part of the problem?

Photo on Unsplash by Haley Hamilton

Helmets cannot prevent the brain from bumping against our skulls and becoming bruised from the inside when jostled. This is particularly relevant in contact sports where players sustain concussions despite wearing helmets. To ensure player safety the NFL recently instituted the “helmet rule”. The rule levies a foul against players who use their helmets to initiate contact with another player. Such a head butt may produce concussions by causing the brain to hit the inside of the skull. Formulating rules to ensure safe play and optimizing protective wearables for contact sports are essential.

Turning to nature for inspiration

Since time immemorial, humans have found inspiration in nature, be it early humans’ cave art, Van Gogh’s and Monet’s paintings or Wordsworth’s poems. It is no surprise then that scientists also seek solutions to human problems in nature’s vast cornucopia.

Two animal species found in the wild have particularly intrigued concussion researchers – woodpeckers and bighorn sheep. The woodpecker is estimated to receive 85 million head impacts across its average lifespan, each over 10 times the force of a football concussion! How is it that these animals can ram their heads into tree trunks or into each other all day long and not show any signs of brain damage? More importantly, can we mimic these animals to design protective gear that makes contact sports safer?

Pileated Woodpecker. Photo by DFChurch on Foter.com / CC BY-NC-ND

One observation from scientific research has been that there is less space within the woodpeckers’ cranium (science speak for skull) for their brains to slosh around in. This is because a bone located near the birds’ jugular vein partially blocks blood flow out of the vein with each peck. This partial occlusion increases blood volume within the skull and reduces brain sloshing. Imagine the expansion of a garden hose if you blocked or restricted the flow of water through it by pinching it shut in the middle. It was hypothesized that if we could similarly increase the intracranial volume in human brains, we could reduce concussion damage.

From the lab bench to the football field

A proof-of-concept study was first performed in rats. Before simulating a concussion, intracranial blood volume of rats was increased by mildly compressing the jugular veins that carry blood out of the brain. Animals that were subject to this compression treatment had very few damaged neurons compared to those that did not undergo compression. These encouraging results provided the impetus to test this approach in human subjects.

Mild jugular compression using Q-collar causes blood vessel dilation. Increased intracranial blood volume may provide a cushion by limiting the brain from sloshing around in the skull. Image from Myer GD et al., Front Neurol, 2016.

Enter the Q-collar (previously also called Neuroshield). Based on the rat study, the Q-collar was designed to mildly compress the jugular veins on both sides of the neck to increase intracranial blood volume. The collar was tested in 15 varsity-level hockey players: 8 in the intervention group wore the collar and 7 controls that did not. Over the course of approximately two months (from pre- to mid-season), changes in brain structure and function were lower in players who wore the compression collar. This was despite the fact that collar-wearing players experienced more collisions and greater impact force than the no-collar controls.

Similar benefits of the Q-collar were also reported in 42 varsity and high school football players: 21 each in the intervention and control groups. Like the hockey study, collar-wearing football players had less damaged brain microstructures at the end of the season compared to their non-collar counterparts. Although collar use did not affect performance on a memory task, abnormal neuronal activation was reportedly lower in several brain regions of collar-wearing players compared to no-collar controls. It is important to note that although the studies were peer-reviewed by a group of external scientists, they were funded by the manufacturers of this collar who stood to benefit financially from the positive findings.

Photo on Unsplash by chuttersnap

Caveats of the collar

Despite being a step in the right direction, the Q-collar leaves several questions unanswered. For example, the studies above were performed in very small numbers of young players who were all male. Whether the purported benefits will hold up in NFL players, players in other contact sports, or in women is not known. Whether the collar will prevent long-term brain damage cannot be inferred based on the short testing period in these preliminary studies. A recent study found protein accumulation in the brains of woodpeckers that was reminiscent of brain damage in humans. This casts aspersions on the efficacy of the Q-collar whose design was inspired by these birds.

The use of this collar by North Carolina Panthers linebacker Luke Kuechly is perhaps a first step toward answering some of these questions. However, experts remain skeptical about the potential adverse effects of this device given that it reduces brain blood flow in highly strenuous situations. Due to these reservations about its effectiveness and safety, the device has not yet been cleared for commercial use by the US Food and Drug Association (although less stringent guidelines allow its sale in Canada).

Concussions and brain damage

Concussions are like a prankster who hides behind a wall and jumps out at us out of nowhere (sometimes scarring us for life). The only way to prevent said prankster from jumping out at you may be to stop hanging out with them. Similarly, there is no way of predicting when we will get a head injury other than ensuring that we do not put ourselves in high-risk situations. High-risk situations can range from signing up for the military, getting in a car, to playing sports. So, short of living an ascetic life, there is probably no way to ensure a concussion-free existence. Since we cannot effectively prevent concussions yet, our best bet is to be able to detect them in a timely manner and prevent further damage.

A year after his death, Belcher’s remains were exhumed and his brain analyzed for signs of chronic traumatic encephalopathy (CTE). Repeated concussive or sub-concussive hits to the head are the primary cause of CTE, a neurodegenerative condition observed most commonly in boxers and football players. Behaviorally it manifests as substance abuse, aggression, suicidal tendencies, dementia, and other psychiatric disorders. Abnormal accumulation of phosphorylated tau protein in the brain is the pathological hallmark of CTE. Neurofibrillary tangles of this tau protein were detected in Belcher’s brain post-mortem.

Editor’s note: There are also potential connections between concussions and later-life dementia, especially for at-risk individuals such as those with ApoE gene variants associated with Alzheimer’s disease. Both negative effects of traumatic brain injury and the negative impacts of neurodegenerative diseases are also intimately linked to metabolic processes in the brain.

Updates on new ways to detect concussions and experimental approaches to treatment in my next post!