SPORT-RELATED CONCUSSION (SRC): Injury without contact to the head
How is the brain injured with no contact to the head/helmet?
In my last blog we explained the mechanisms of injury causing SRC and how the brain moves in reaction to the mechanism of direct impact to the head/helmet, as well as how injury occurs. The mechanism of indirect impact in which there is no contact to the head/helmet causes the head/helmet to move suddenly or violently. This abrupt movement by the head/helmet exerts inertial forces to the brain which can result SRC. Again, sudden acceleration and deceleration of the head/helmet is what causes SRC. This mechanism is referred to as a whiplash brain injury. Let’s explore what is happening to the brain inside the skull with an indirect impact.
Whiplash is defined as an abrupt snapping motion or change of direction resembling the lash of a whip.[1] Any hit to the body can cause the head and neck to whip in any direction and can cause SRC. The two most common in football are an impact to the quarterback getting ready to pass or a receiver catching a pass.There are two possibilities of brain movement within the skull during these whiplash brain injuries. 1.) The head/helmet and brain continue to move in unison, accelerating at the same speed togetheruntil the head/helmet comes to zero velocity and changes direction; or 2) Upon contact, when the body stops moving, the head/helmet (which weighs 12- 13 pounds) accelerates at a faster rate than the brain (which weighs three pounds). [2]
A receiver comes across the field on a pass route and gets hit in the chest by a defensive back allowing for his head/helmet to continue moving forward. The posterior (or back of the skull) is pushing the brain forward. The head/helmet and brain accelerate together until the head/helmet whips to a stop when the chin is near the chest, reaching zero velocity. The front of the brain (dura mater) has maintained its space with the anterior aspect of the skull until it comes to zero velocity. But the back side of brain separates and continues to compress toward the front side as the head/helmet comes to a stop and begins pushing the brain in the other direction. This compression occurs until the momentum of the entire brain has changed direction. The same thing now happens moving in the posterior direction, but now the brain is being pushed by the anterior side of the skull. This time though, when the head/helmet comes to zero velocity, there is separation between the posterior brain and skull. The brain continues to accelerate toward the skull as it changes direction and comes back and strikes the brain and begins pushing it anteriorly again.
Now, let’s look at what happens if the head/helmet’s momentum causes the head/helmet to accelerate faster than the brain. The posterior skull then pushes the posterior brain forward, but in this case since the brain’s acceleration is less than the head/helmet, the front of the brain begins to separate from the anterior aspect of the skull and compression of brain starts even though both head/helmet and brain are moving in the same direction. When the head/helmet comes to zero velocity and changes direction, it hits the brain and begins pushing it posteriorly until the entire brain brain’s momentum is changed and moving in the same direction. Now the same thing occurs in the posterior direction as described above.
In both scenarios the head/helmet and brain motion continue as described until the head/helmet decelerates and comes to a complete stop. In both, the head/helmet and brain motion of acceleration/deceleration occurs with any indirect impact. The only thing that could change is the direction of movement. The key is that the acceleration/deceleration of the head/helmet is what causes the acceleration/deceleration of the brain inside the skull by pushing the brain.
As with direct impacts, the brain does not bounce back and forth inside the skull with indirect impacts. The brain is pushed back and forth from the acceleration and deceleration of the head/helmet. Therefore, to reduce the risk of SRC we must go beyond the helmet with new technology which slows down the motion of the head/helmet in both indirect and direct impacts. Helmets cannot slow down the head and therefore do not and cannot protect the brain against all forces and energy that act upon it. It is the kinetic energy of the brain’s own motion which elicits forces causing SRC.
There has been much discussion about whether helmets work or don’t work in the protection against SRC. My next blog will discuss what a helmet does and what it does not do. Helmets protect heads. Kato Collar protects brains!
SPORT-RELATED CONCUSSION (SRC): What happens inside the skull?
SRC is a traumatic brain injury induced by biomechanical forces; it may be caused either by a direct blow to the head, face, neck or elsewhere on the body with an impulsive force transmitted to the head. [1] To simplify, SRC in football occurs from direct impact that causes contact and inertial forces to the head and from indirect impact that causesonly inertial forces to the head. A direct impact to the head/helmet causing the head/helmet to decelerate and accelerate can occur with helmet-to-helmet, helmet-to-shoulder pad, helmet-to-body, or helmet-to-ground forces. An indirect impact is caused when there is no contact with the helmet, but the head/helmet moves suddenly or violently. This can occur with body-to-body impacts causing the head to change direction rapidly. In both cases of direct or indirect impacts, the point of emphasis is that THE HEAD MOVES in the majority of impacts in football. Most experts agree that abrupt acceleration/deceleration of the head is the cause of SRC. But the question to be asked in the prevention of SRC is “What is happening to the brain during acceleration/deceleration of the head?”
DIRECT IMPACTS
If you are following my posts, we learned last week, that based on the structural anatomy of the brain, it is separate from the skull and does not bounce. If the brain does not bounce (even though many are taught that it does), then what does the brain do? One mechanism of direct contact is helmet-to-helmet in which both move with velocity and direction. During contact each helmet comes to zero velocity prior to changing direction and then they accelerate away from each other and reach a new velocity based on their momentum. Does the brain reach zero velocity at the same time as the helmet? Of course not! It is separate from the skull. The brain is still accelerating in the direction of the contact because it is separate from the head/helmet. The part of the brain closest to the point of contact moves into the skull first as the back side compresses. The brain does not begin to decelerate and reach zero velocity at the same time as the head/helmet. It continues in the same direction until the head/helmet changes direction and begins pushing the brain in the opposite direction of contact. The energy that is elicited to the brain is not from the contact, but from its own kinetic energy of motion toward contact site. This push of the brain by the head/helmet continues until the entire brain’s momentum is moving in the same direction as the head/helmet. Important to note: Deceleration of the head/helmet to zero velocity on contact occurs while acceleration of the brain inside the skull continues. One is slowing down, and the other is not.
What happens next? The head/helmet continues to accelerate moving away from the contact pushing the brain until the head/helmet whips to a stop coming to zero velocity. When the head/helmet stops moving, the brain is now accelerating with its own momentum inside the skull. The brain separates from the contact side of the skull and continues in motion with its own velocity in the direction the head/helmet reached its zero velocity. As this motion of the brain occurs, the head/helmet begins accelerating back towards the contact site and hits the brain pushing it in the opposite direction. This continues to occur until the head/helmet stops moving. Important to note: During this second contact of the brain with the skull, the brain is accelerating in opposition to the acceleration of the head/helmet. They are in motion and accelerating toward each other.
All of the mechanisms of injury are what we call SRC, and they occur in less than a second. The head/helmet stops moving in less than a second in most incidences. Does the SRC occur with the first contact of the skull and brain or the second contact? Or do both contribute to the SRC? Based on our previous post about the narrative created by helmet companies and the NFL, it only occurs on the first contact between the skull and brain as the helmet only works during direct contact.
I believe that injury to the brain (SRC) undoubtedly occurs with both the first and second contact of the skull and brain. One could even make the argument that even more force elicited to the brain on the second contact of brain and skull than the first. Here’s why! When a player is setting up to block his opponent on a kickoff return and they hit helmet-to-helmet, the blocker is usually the player who sustains a concussion. The blocker’s head/helmet has very minimal motion and velocity upon contact with the opposing player’s helmet. For all practical purposes, the head/helmet and brain of player blocking on the kickoff are not moving when struck by opponent covering the kick. Therefore, both head/helmet and brain are basically at zero velocity when contact occurs. The direct impact causes the blocker’s head/helmet to move, and the inferior side of the skull pushes the brain in the direction the head/helmet is moving after contact. Important to note: In this first contact of skull to brain the head/helmet is accelerating into the brain which is fairly stationary with little or no acceleration or deceleration. The head/helmet accelerates based on the momentum created by impact and begins pushing the brain. The mass of the head/helmet is 12-13 pounds; it is pushing a 3-pound brain. [2.3] When the head/helmet comes to zero velocity as it whips to a stop the brain is now no longer in contact with the skull and its momentum and acceleration is less than the head/helmet. As the head/helmet comes out of zero velocity, it changes direction and moves back toward the brain, striking the brain which is still moving in the direction the head was moving prior to its change of direction. Important to note: The head/helmet and brain are accelerating toward each other.
Back to the question of does the SRC occur with the first contact of the skull and brain or the second contact? Or do both contribute to the SRC? I believe it is very clear that there are forces elicited to the brain after direct impacts to the helmet that attribute to SRC. It is also apparent that the brain is not bouncing back and forth inside our skulls but is being pushed back and forth by the momentum of the head/helmet after direct impact. Therefore, it is important to understand that movement and speed of motion of the head/helmet after direct impact significantly increases the chance that a SRC can occur. Which is why technology going beyond the helmet is necessary to prevent SRC. The necessary innovation must decelerate the head/helmet after impact.
More support for this necessary technology will come in my next blog which addresses SRC caused by indirect impacts.
Consensus statement on concussion in sport—the 5th international conference on concussion in sport held in Berlin, October 2016;McCrory P, etal; Downloaded from http://bjsm.bmj.com/ on January 2, 2018 – Published by group.bmj.com;
Helmet companies want us to believe the brain bounces back and forth after impact that is what causes a SRC. And the NFL has coined the term HeadHealth having us believe the term means they are addressing the brain and SRC. Neither are the whole truth! The brain does not bounce and HeadHealth does not always address brain health. In order to better understand this, we need to review the structuralanatomy of the brain. It is absolutely crucial to understand that the brain is separate from the skull. When the literature regarding the mechanism of injury for sport related concussion talks about the head, in most instances, they are referring to the brain and the skull as one unit. But when defined by human anatomy the upper portion of the body consisting of the skull with its coverings and contents, including the lowerjaw is defined as the head. The brain might be contained in the skull, but the brain and head are two separate entities. You can move your head, and your head moves your brain. You cannot move your brain inside your skull.
The best way to see this is through a picture of how the brain is housed inside the skull.
The theories we have been led to believe about how the brain moves in a concussion I will call the “Bouncing Brain Theory” and the “Floating Brain Theory”. From Figure 1 and 2 above you can see the different layers and spaces between the skull and the cerebrum which lies just below the pia mater. In most pictures like this the cerebrum is labeled the brain (as in Fig. 1) which can be confusing when talking about a SRC because everything below the skull is part of the brain and includes the dura mater which lies directly next to the inferior side of the skull . . Pictures like this also make us think there is a significant distance between the skull and the cerebrum and other structures of the brain. When in reality the space between the inferior skull to the cerebrum or other parts depending on the location is only .4 and 7 mm which is extremely small.[1] Most of the cerebrospinal (CSF) fluid lies in the subarachnoid space which leads to why we are made to think that the brain bounces or floats. These two facts: 1) the brain is separate from the skull; and 2) it is packed inside very tightly should make it easy to deduce that the brain cannot bounce back and forth. But there is other anatomy of the brain which also keeps the brain from bouncing or floating.
In addition to this, CSF and the ventricles contained within the brain integrate with the CSF contained in the spaces between the linings so that the CSF flows in a system designed to protect the structures of the brain enclosed by the skull (Fig. 3).
The ventricular system consists of four ventricles within the brain which do provide some buoyancy to the brain in order support and protect structures, but not enough to make it float around inside the skull. CSF surrounding the brain combined with flowing through the four ventricles and folds protect the brain by acting as a shock absorber and supporting the brain through suspension by providing buoyancy. [2,3]
And then you incorporate the corpus callosum into the mix which is the largest commissural tract in the human brain, with 200-300 million axons connecting the two cerebral hemispheres. [4,5] The corpus callosum (Fig. 4) is a thick bundle of myelinated nerve fibers 10 cm long and 25 mm high made up of white matter. [6] White matter has a higher elastic modulus than gray matter and myelination of nerves increases this modulus of elasticity.[7] Elastic modulus is a quantity that measures a substance’s resistance to being deformed elastically when a stress is applied to it, and white matter (corpus callosum) has an elastic modulus which on the average is 39% stiffer than gray matter (cerebrum).[8,9] So not onlyis the corpus callosum’s function to connect the two cerebral hemispheres for communication but based on its histological make up it is a supportive structure of the cerebrum during excessive motion caused by forces acting on the brain from the different impacts causing SRC.
Based on the brain’s mechanical and structural anatomy designed to absorb the kinetic energy created by its own movement in reaction to impacts causing violent movement of the head the brain is not bouncing back and forth inside the skull as depicted in the movie “Concussion”. The brain’s motion is always and only in reaction to the movements of the head. The head initiates all movement and contact of the brain that causes a SRC.
My next blog will explain the types of impacts and the mechanisms of injury which cause SRC.
Ethnicity Influences Corpus Callosum Dimensions.Hilda Nouri Hosseini,1 Mohammad Reza Mohammadi,2 Mohsen Aarabi,3 Narges Mohammadi,4 and Mohammad Jafar Golalipour; https://www.hindawi.com/journals/nri/2018/8916035/
Axon position within the corpus callosum determines contralateral cortical projection Jing Zhou, Yunqing Wen, Liang She, Ya-nan Sui, Lu Liu, Linda J. Richards, and Mu-ming Poo; PNAS July 16, 2013; 110 (29) E2714-E2723;https://doi.org/10.1073/pnas.1310233110
My name is Jeff Chambers and I have been a Certified Athletic Trainer for approximately 40 years. I provided health care to student athletes for 35 of those 40 years.
Except for the interruption of CoVid, sport-related concussion (SRC) has been the most researched injury over the past 10 to 12 years, receiving significant attention from the media. Millions of dollars have been spent on SRC during the same 10 -12 years. The NFL alone has allocated close to $20 million in concussion research and in awards toward the prevention of SRC (1).
As a Certified Athletic Trainer, I evaluated and cared for student athletes with this injury throughout my career. As a result, I have been studying the mechanism of injury (MOI) and causes of SRC for the last 12 years and the burner/stinger injury for over 20 years. Throughout my experiences, many questions regarding SRC arose that I wanted answered so I began my own research. But after sifting through countless journals and articles, the answers I was seeking could not be found.
However, I discovered that everything we believe about how SRC occurs is all based on theory. And what we are led to believe about the causes of SRC is not the whole truth. In my following posts I am going to address the questions and topics below based on my review of the literature, research about prevention of SRC, and my extensive experience with SRC:
What is the narrative we have been led to believe about prevention of SRC?
How was it created?
Who created it?
Does the brain bounce? Does the brain float? What does it do?
Do helmets prevent concussions? When? Where? How?
Does neck strengthening prevent SRC?
Can helmets become culpable in SRC?
Does corporate business really care about our youth playing football?
Are there other ways to prevent SRC?
What new technology is available to prevent SRC?
What is the technology is needed to protect our youth?
Before launching Kato Collar, we performed two independent biomechanical tests at NTS Chesapeake Testing and Lakehead University in the same manner football helmets are tested in the laboratory. During testing, Kato Collar lowered multiple measures of head impact severity that are associated with the risk of concussion.
In this short video clip, I explain our testing process, address what 30% impact reduction means and show a demonstration of an impact on a helmeted head, both with Kato Collar and without.
You can watch the short video explanation here ⇒ VIDEO CLIP
You can also read an in-depth report about our research here ⇒ WHITE PAPER
When it comes to anatomy of the head, the first thing we need to understand is that the brain is not attached to the skull. And the best way to think about this is you cannot move your brain inside your skull. Muscles do not attach to your brain to move it. Your brain only moves when your head moves. This is key in understanding how helmets and how Kato Collar work together to prevent head injuries in football.
In this short video clip, I explain how our technology works and why it as important as a helmet in protecting players. Make sure you listen closely at the one-minute where I give a very clear analogy. This video is the first in series on Kato Collar – stay tuned, stay informed, stay safe and play football.
Concussions & CTE: What We Know
Over my 35 years of experience as an athletic trainer, I needed to communicate with athletes, coaches, parents, and physicians in a way that each understood what had occurred. In the most basic of words, a concussion is any blow to the head or the body that causes enough injury to the brain to elicit symptoms such as being dazed, confused, clumsy, lightheadedness, and/or impaired vision.
When it comes down to it, the diagnosis of a concussion is subjective. Currently there are no objective diagnostic tests that can be performed to confirm a concussion or determine severity. Most diagnostic tests are performed to rule out a serious brain injury, that could lead to permanent damage or catastrophic results. These tests are designed to diagnose Traumatic Brain Injury. Signs are different from symptoms. Signs are what can be observed, and symptoms are described by the athlete.
I don’t assume that everyone follows along with the current news about concussions and the information that we are learning about the destructive impact of CTE. These are serious; and most coaches and trainers have taken this very seriously throughout their careers. Yet we need to improve our game: There are safer ways to play while keeping the integrity of the sport alive.
What causes concussions? A concussion is a serious injury to the brain resulting from the rapid acceleration and deceleration of brain tissue within the skull. Rapid movement causes brain tissue to change shape, which can stretch and damage brain cells. This damage also causes chemical and metabolic changes within the brain cells, making it more difficult for cells to function and communicate. (Source: Concussion Legacy Foundation)
What is CTE? Chronic Traumatic Encephalopathy (CTE) is a degenerative brain disease found in athletes, military veterans, and others with a history of repetitive brain trauma. The best available evidence tells us that CTE is caused by repetitive hits to the head sustained over a period of years. Most people diagnosed with CTE suffered hundreds or thousands of head impacts over the course of many years playing contact sports or serving in the military. And it’s not just concussions: the best available evidence points towards sub-concussive impacts, or hits to the head that don’t cause full-blown concussions, as the biggest factor. (Source: Concussion Legacy Foundation)
With a drop in youth football participation, few improvements to the gear that protects players on the field, and a lack of innovation, we believe there is ample room for improvement.
One airbag doesn’t save your life in a crash. Just like a helmet alone will save you from a concussion. When you are the field, you build confidence through technique and the right gear. Training, such as Heads Up, educate our players about a safer way to tackle. We realized there is a blank space out there; rapid acceleration and deceleration of the brain within the skull.
As shown above, with state-of-the-art testing done at Chesapeke Labs our collar is able to slow deceleration of the brain by up to 30%. Our objective is athlete safety. We designed Kato Collar to help provide protection against concussions, and decelerating the brain by nearly a third is going to make a positive impact on addressing that. We are committed to athlete safety and will continue to research and innovate ways to do that in football, as well as other high impact sports.
As more comes out in the research, theories are developing about what occurs inside the skull that causes injury to the brain after impact. I believe there is more to uncover with our approach to training, equipment, and how we improve recovery procedures. By first understanding and utilizing a common language, we’ll begin to realize how to approach concussions as they happen.
suspension by providing buoyancy. 