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Concussion Management
Program Development
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& Minor Sports


Concussion Management Consultation Services
For School Boards


Concussion Management Consultation Services
For Minor Sports


CMP Program Development Guide
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Program Development Guide 
What is a Concussion?
Signs, Symptoms & Behaviours
A Partner Approach
Understanding The Brain
Essential Elements
Baseline Assessment
Concussions & The Law

Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012
British Journal of Sport Medicine with Links to Related Reference Articles
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Review of Statement by CMP
Child SCAT 3
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(An excerpt from Chapter Nine of the CMP Program Development Guide which is provided to all people who participate in one of the Training & Program Development Workshops Sponsored by CMP Concussion Management Partners Inc.)



We feel that in order to fully appreciate the seriousness of sport-related concussions, or of any form of traumatic brain injury, it is important to have a basic understanding of how the brain functions under normal circumstances and what actually takes place when your brain suffers an injury.


Before you continue, it is recommended that you take the time to watch a special 30 minute video that we have created entitled, Understanding The Brain. By watching the video and reading the rest of this section, you should have a good idea of what happens to your brain when it suffers a traumatic brain injury. 


We will now examine this incredible machine we call the brain. There is nothing like the human brain. No man-made computer even comes close to the capacity of the human brain. However, when the brain experiences a traumatic injury, a whole lot of things happen that are cause for concern. We will take a look at a very simple, basic explanation of how the brain works under normal circumstances and what happens inside the brain when it is injured.

As you gain a better understanding of how your brain works, you will appreciate why it is important for us to have an effective concussion management program in place for student-athletes who suffer sport-related traumatic brain injuries.


Robert Kirwan is shown making the following presentation to a group of coaches who were taking part in a Concussion Management Training Seminar. A close-up photo of the skull is shown below.

The adult human brain is a soft, jelly-like organ that weighs about 1500 grams (3 pounds) and is about 1200 cubic centimeters in volume.

You could fit the human brain into one of the three milk bags you get in a 4L package of milk.

There are over 100 billion neurons in the brain. We often refer to these as brain cells.

Each of these neurons includes between 1000 and 10,000 protrusions called dendrites which are used to receive electrical signals from other neurons. 

The electrical signals travel through axons, which are long slender tubes and projections that conduct electrical impulses and allow biochemical reactions to take place across a tiny space called a synapse at the point where the axons meet up with dendrites. 

Axons and dendrites don’t actually touch. They just come very close to each other. Close enough for the chemical neurotransmitters to jump across from the axons to receptacles in the dendrites.  

Each neuron has one axon which takes electrical impulses "from" the sending neuron to as many as 10,000 dendrites of other neurons.  

The dendrites "receive" electrical impulses from other neurons, then transform the energy to create its own neural signal pattern before sending it to other neurons in its network though its own axon.

The diagram below will show you how the neurons communicate with each other. Now imagine each axon branching off to go throughout the brain, connecting to thousands of other neurons that will become part of the specific communication network that is needed in order for this particular function to take place. Imagine how many neurons will be included in any one of these networks and you have some idea of just how complex the operation of the brain really is.

To give you another idea of just how incredibly small this complex structure is, if you could lay all of the axons that are inside your brain connecting the nerve cells, end to end, you would be able to go around the world at the equator over four times. That’s about 160,000 km of axons all jumbled up together inside your brain providing the communication link between the 100 billion nerve cells contained in your brain – the central nervous system.

All of this fits in a space about the size of a milk bag and weighing about 3 lbs or 1500 grams.   

The neurons and axons make up only part of the volume of the brain. Scientists differ on just how much of the volume this consists of, but the rest of the volume consists of glial cells. Glial cells provide support and protection for the neurons and assist in some way with the communication between neurons. 

There are four main functions of the glial cells. 

  1. They surround the neurons and axons, holding them in place. 

  2. They insulate one neuron from another and keep the axons separated from other axons so the wires don’t cross inadvertently. 

  3. They supply nutrients and oxygen to the neurons. 

  4. And, they destroy and remove dead neurons, essentially keeping the brain clean.

Early studies of the brain estimated that up to 90% of the volume of the brain consists of glial cells. More recent studies take the position that the balance is more like 50% of glial cells with the other 50% being neurons. Regardless, both neurons and glial cells play critical roles in the central nervous system.  


There are a number of theories why it takes a child’s brain longer to recover from a concussion. The developmental differences between an adult and an adolescent are significant and these differences influence how the brain reacts to trauma.

The first consideration deals with the substance which surrounds the axons. This substance is known as myelin. It is like the plastic coating that you find on electrical wiring in your house. The coating protects the wire and allows for efficient transmission of electricity. You can twist and bend the wire and the coating protects the copper wiring inside. The axons of an adult have the same kind of protection. The myelin is built up and works to protect the axons from injury. Concussions still occur in adults, but it takes more force to damage the axons because of the protection from the myelin.

Children and adolescents have less myelin since their brains are still developing. Therefore it is much easier for damage to occur to the axons and it takes less force to cause stretching or shearing of axons that are not as protected as with adults.

Another development issue has to do with the size of the head which is disproportionately larger relative to body size during childhood and adolescence. This extra size and weight influences the force that is being applied to the brain as a result of blows received to the head and body during sport competition.

The final development issue we will consider deals with muscle development. The muscles in a child and adolescent are not yet fully developed, therefore the student-athlete may not be strong enough to brace for contact. This lack of development is critical in the neck area which has a lot to do with the movement of the head following a body blow.

So when you consider the size and weight of the head relative to the rest of the body; the lack of muscle strength; and the lack of myelin protecting  the axons running through the brain, it is easy to see why children and adolescents take longer to recover from concussions.



It is a very complex process, but the ability of nerve cells to effectively communicate with each other along a complicated network is what allows you to function as a normal human being.

A concussion changes the way the brain normally functions which is why this is such a serious injury and should not be taken lightly.

If you look to the diagram to the left, you will notice that the axon from one neuron never actually touches the dendrite of another neuron. Instead, it meets at a place that is called a synapse, which is the name of the small space between the end of the axon and the end of the dendrite. Let me repeat - the synapse is the name of the "space" between the axon and the dendrite. This is an important point to remember.

As amazing as it sounds, from what we know about the brain, it would appear as if we have over 100 billion neurons, each with up to 10,000 dendrites, connecting through a single axon to up to 10,000 other dendrites, and yet no two neurons are actually physically connected. They are all separated by a small space at the synaptic junction.

The actual communication is by chemical neurotransmitters that influence the receiving neuron. No two of the more than 100 billion neurons are actually physically connected. This is an amazing phenomenon that is hard to comprehend considering the small space inside the skull.

So, to repeat, when an electrical signal is sent through the axon, it creates a chemical reaction that produces neurotransmitters which are sent across the synapse to receptors on the dendrite. When this happens, the receiving neuron transforms the signal from the sending neuron to its own special electrical signal and then sends that signal along to thousands of other neurons through its own axon.

The diagram below will give you another overview of how information flows through neurons throughout the brain.  


When your brain suffers an injury that results in a concussion many things happen all at once and as a result some of those dendrites and axons may be stretched or broken. There is also a tremendous power surge as billions of neurons send out electrical impulses simultaneously, releasing a cavalcade of neurochemicals from the axons in the brain.

This results in a disruption or disconnection of the pathways between many of the nerve cells and causes all kinds of problems in the way messages are communicated and distributed throughout the brain. With over 160,000 km of axons weaving their way through the brain to neurons in many areas of the organ, the interruption of the signal pathway along a single axon could have significant impact on the functioning of the brain and may produce a wide variety of symptoms depending on which pathways have been affected.

The power surge of energy as the neurons all fire up their electrical signals at once, coupled with the release of chemicals into areas of the brain where the chemicals may not have been before, adds to the crisis situation and causes all kinds of unpredictable events to occur.


Keep in mind that most of what we know about the brain has just recently been discovered.

But what we do know for sure is that each one of the 100 billion nerve cells can connect with thousands of other nerve cells through these dendrites and axons which wind their way around the brain.

In fact up until about the age of 20 your brain is continually forming neural connections until you reach up to about 1,000 trillion connections between nerve cells. As you get older about half of the connections are discontinued in a sort of pruning process, mainly because they are not being used, but you will still end up with no less than 500 trillion connections between neurons for most of your adult life. The period when you have the greatest number of neural connections is during adolescence, from ages 13 to 19, typically the years when you are in the intermediate and senior grade levels of secondary school (Grades 7 through 12)


Dendrites and Axons, therefore, are similar to telephone wires or internet cables carrying the messages being sent between nerve cells in the brain and throughout the body via the spinal column to and from the brain. This is why the brain is called the “central nervous system”. It acts a lot like a bus terminal where signals are sent and then distributed elsewhere depending on where they can be put to best use.

Everything you do is the result of electrical impulses and biochemical reactions that travel through some of the 160,000 km of axons connecting each of the 100 billion nerve cells in your brain to thousands of other nerve cells, resulting in up to 1000 trillion different connections in total, all producing chemical reactions across the synapses that permit communication to take place.

As well, the neurons inside your brain are connected through the brain stem and the spinal cord to the nerve cells and sensory cells throughout your body, sending signals that tell your body how to function.

Just reading these sentences involves thousands of nerve cells being connected along hundreds of km of axons, producing millions of neurotransmitters that are being taken in by millions of receptors, and all of this happens in a split second. If I tell you to put your finger on the letter Q on the key pad, just think of what your brain has to go through to make your finger actually move to the keyboard letter. This simple command requires memory, vision, muscle coordination, reasoning, etc. All of this is instantaneous, even though the communication is being sent along neural pathways that are in a variety of different areas of the brain.

The brain is an incredible machine that is pretty durable under normal circumstances. But if something happens to cause the brain to suffer any kind of injury, there are so many things that can go wrong because of its complexity.


Something else you need to know is that the brain is submerged in cerebrospinal fluid (CSF).

This fluid occupies the open space inside the skull and among other things, provides buoyancy for your brain.

CSF also protects the brain tissue from damage against the inside of the skull during normal movement of the head or body. It provides a cushion between the brain and the skull bone, so the brain doesn't strike the skull very often under normal conditions.


There is normally space for about 130 to 150 ml of CSF in side the skull and it is replaced about 3 or 4 times a day, draining into the blood.

The intracranial pressure is maintained by the body at a fairly constant level by maintaining just the right total volume of CSF; just the right amount of blood flow to the brain; and obviously by the composition of the brain itself.

Any increase or decrease in one of the three elements (CSF, blood flow, or volume of the brain) means that one or both of the other two must be reduced or increased in order to maintain the right amount of intracranial pressure. Since the brain is a constant size and the blood flow doesn’t change much, and since the CSF is constantly being produced and drained so often each day, the body usually uses the amount of CSF production to keep the pressure constant whenever the need arises.


The cerebrospinal fluid provides buoyancy for the brain, so even though the brain has an actual mass of about 1500 grams, the net weight of the brain suspended in the normal amount of CSF is equivalent to a mass of only 25 grams, or about the weight of two normal sized grapes.

This is important since it allows the brain to maintain its density without being impaired by its own weight which would cut off blood supply and kill nerve cells in the lower sections of the scull cavity without the right amount of CSF.

Keep in mind that without the CSF the brain would feel 60 times heavier.

The amount of CSF is extremely important in order to provide what is known as neutral buoyancy. This means that the net weight of the brain allows it to be "suspended" in the CSF instead of floating to the top of the skull or sinking to the bottom. The suspension of the brain in this state of neutral buoyancy allows it to keep its shape and density. If it sank or floated it would rest up against the top or bottom of the skull, placing pressure on the blood vessels, restricting blood flow and killing off neurons. The amount of CSF is critical to the functionality of the brain.

Therefore, as the brain is suspended inside the skull, it feels very light, which is why we can move around a lot and not feel anything moving around in our head. Even most rapid movements of the head would not produce much of an impact against the side of the skull since the brain feels so light when everything is normal.


So, to be clear, what you have inside your skull is your brain matter (basically dendrites, axons, nerve cells) which takes up about 1200 ml of space; the CSF fluid which takes up another 130 ml of space; and the remaining portion consists of blood vessels. All of this is kept together inside a bag called the dura.


In order to better understand what happens when the brain is injured, we would like to take a bit of time to examine the main parts of the brain and their functions.

The Frontal Lobes are located at the front part of your head, just behind the forehead. This part of the brain is very prone to injury because it is very close to the ridges of the skull and in many instances with head-on force this area slams against the bone. This part of your brain is responsible for helping you make plans, organize things, solve problems, and effectively use your memory. It is also the part of your brain that controls your emotions and impulses and helps you maintain socially acceptable behaviour. It also helps you with your ability to pay attention to details and to make decisions. Finally, this area plays a huge role in your speech and language abilities.

The temporal lobes are found at the sides of the brain behind the frontal lobes right around the level of your ears. This part of the brain is responsible for your hearing and for helping you to recognize and understand sounds and speech and also to produce speech for communication purposes.

This part of your brain is located right at the lower back of the head and is where you process visual information which is sent from your eyes. It helps you make sense out of what you see and perceive shapes, colours, sizes, and distance.

This part of your brain is located right behind your frontal lobes. It is the part of your brain that integrates the sensory information that comes from all parts of your body when you touch things or feel hot, cold, etc. The parietal lobes also help you with some of your balance and give you the ability to navigate around without bumping into things.

The cerebellum is located at the back of the brain and controls your balance, movement and co-ordination. It allows you to perform the physical activities that are necessary for sports and just for movement in general. It is the area of your brain that is most involved in coordination of all parts of your body.

The brain stem is located at the base of the brain and controls all of the functions that are necessary for survival, such as your breathing, heart rate, and blood pressure. These are all of the involuntary functions of the brain that you do without thinking.


The brain is a very complex system that serves us well normally. However, when brain trauma occurs that results in a concussion, the damage can be widespread and can impact any number of these sections. Because of the interconnection of neurons, and the fact that each neuron can be connected to up to 10,000 other neurons, and each of those neurons can be connected to up to another 10,000 neurons, and so on, it is safe to say that whatever happens to one neuron may in fact have an effect that reaches all parts of the brain. We will accept that in most cases the impact may be negligible, but nonetheless, there is an impact and if enough neurons are damaged or enough of the axons are stretched and/or sheared, there can be significant and widespread damage.

You don’t need a medical degree to see that the different parts of the brain work together in order for one to function normally. Damage to the Frontal Lobes will definitely have an effect on how you respond to what you see and the signals coming from your Occipital Lobes. And if you have damage to your Cerebellum, thus affecting your balance, it is going to have an impact on multiple regions of your brain.

This is why any force to the body that results in the brain moving violently inside the skull gives cause for concern. Let us see what happens to the brain when it is injured.



There seems to be general agreement that a concussion is caused by a direct blow to the head, face, neck or any other part of the body. Loss of consciousness is not necessary for a concussion to occur. In fact, only a small percentage of concussions involve loss of consciousness.

The force of this contact, no matter where it occurs, causes the brain to move violently from side to side, front to back or rotationally within the skull. As a result, the brain as a whole is stretched or squashed slightly as it bangs against the inside of the skull, causing it to change its shape and become temporarily deformed. It very quickly returns to its original shape, even though it may be a bit swollen from striking the inside wall of the skull.

No matter what definition you use, the fact remains that a concussion changes the way the brain functions. What is not known at this time is how long or how permanent the damage will remain.

Many people refer to a concussion as a "temporary Traumatic Brain Injury" or a temporary TBI. You will often see the definition include reference to the "rapid onset of short-lived impairment of neurological function that resolves spontaneously".

However, there is great debate going on now as research points that the impairment of neurological function may not repair as rapidly as once thought and the resolution may not be as spontaneous as we had hoped.

This temporary impairment may be true for the most obvious symptoms such as headache and dizziness, but the long-term impact of a concussion may result in impairment of emotional and psychological functions as a result of the changes that occur in the brain.

In fact, there are studies that have found middle aged adults who suffered concussions while in college exhibiting premature brain aging and deficiencies in concentration, balance and motor control many years after suffering their concussions. It is most likely that most people who are suffering from these kinds of functional deficits may simply attribute them to normal aging and getting older, not even relating any symptom or deficit to their history of concussions. And yet, there may be things they could have done during rehabilitation that might have reduced or eliminated these functional deficits, thus impacting on their quality of life many years after the injury. Our goal in developing the most effective student-athlete concussion management program possible is to reduce the long-term consequences of sport-related concussions.


Evidence is being produced by researchers which proves clearly that a "concussion is a process". It is not an event. And this process does not simply involve "healing and recovery". Many symptoms of concussion do not present themselves for hours, days, weeks or months. In fact some people admit to experiencing concussion-like symptoms for many years following an injury.

We will concede that there may well be a rapid onset of short-lived impairment of neurological function in some areas that resolve spontaneously, but what about the long-term impairment that does not resolve. What about personality changes? What about anxiety and mood disorders? What about interpersonal relationship skills? What about one's attitude towards life? These are all recognized as signs and symptoms of concussion but they are also unfortunately accepted by most people as part of growing up and normal development. They may not be that normal after all.

Admittedly, we all change our personality slightly from time to time. We all have periodic bouts of anxiety and we are all moody from time to time. We all have some difficulties with relationships and our attitude towards life is often affected by our environment and the people around us. But for young people who suffer a concussion, are these changes part of their natural evolution, or are they consequences of their brain injury? And is there something we can do to reduce the risk of life-altering consequences?

Symptoms of a concussion may also not be evident until you are required to perform a specific task. For example, you may not even know that you are no longer able to recall math facts until you are asked to recite your times table. You may not realize that you get dizzy riding a bike until you have a chance to ride a bike. You may not know you have problems adjusting your vision when things are being thrown quickly in your direction from the side until this actually happens. These symptoms take time to present themselves and they will only be noticed if you have people around you who are looking for signs and symptoms of concussion. That is why we use the "partner approach" to concussion management.


Axons get their shape from internal structures called microtubules which look like a string of sausages strung together. As the shape of the brain gets temporarily deformed from the twisting or rapid acceleration and/or deceleration, the axons may stretch or break. Normally, since your brain is constantly jiggling like a mold of jello, axons are often stretched gently with no damage to any of the internal skeletal structure that is found inside axons. This is what is often referred to as a “slow stretch”.

If the axons are stretched too quickly, they tend to stiffen up causing their internal skeletons to become destroyed and the axons will shear, causing a total interruption of signals. In most cases, concussions are less severe injuries where the axons do not actually shear, but rather are stretched with enough force that they don’t quite rip apart but still sustain significant damage to their internal skeletal structure.

For example, if the axon is stretched hard enough, the microtubules that act like conveyor belts carrying nutrients from one end of the axon to the synaptic connections in its network may break at some point. When this “conveyor belt” is broken, the supplies that are being carried will continue to flow but they will basically “fall off” at the break and will collect inside the axon. This causes a “bulb” to form inside the axon. More importantly, it prevents the part of the axon beyond the break from receiving the nourishment and supplies it needs to survive. Eventually, the part of the axon that is not receiving nourishment will wither away and die, thus disconnecting from the original axon. That means that signals that would normally have gone along that axon will no longer get through. This then causes the axons with the bulbs of protein to also shrivel up and die because they can no longer do what they are supposed to do and the neuron will die as well. All communication that was conducted that one neuron will then cease.

There are some injuries where the damage is beyond repair, but the communication is still continuing in a faulty manner. The signals are getting through but they are not clear. In this case the damaged connection may end up corrupting the entire system with static communication.

Dr. Douglas Smith of the University of Pennsylvania and a number of his colleagues have done extensive research on concussions and axonal damage. What they found is that if you stretch an axon gently the first time, it produces an increase in the number of tiny pores that line the outside skin of an axon. These pores allow sodium and calcium to come inside. If you stretch the axon gently a second time shortly after the first time, these tiny pores became enlarged and sodium and calcium came rushing in. Other scientists had previously discovered that increased levels of calcium in an axon created an enzyme that actually ate away the internal structure of the axon. Therefore, the implication is that if a person suffers a seemingly minor blow to the head or body, there may not be any obvious symptoms of concussion present, but the stretched axons will be extremely vulnerable if there is another minor blow. That is why some people are surprised when they receive serious concussion-like symptoms from what seemed like a very small force. It’s because the axons were vulnerable at the time from the stretching caused by the first blow.


When the brain suffers from a force as a result to a blow to the head or some other part of the body, it experiences a "power surge" producing an extreme amount of chemical neurotransmitters, effectively "lighting" up the entire brain with electrical charges. This surge only lasts a minutely brief period of time and seems like a mini-seizure. The physical movement causes neurons and axons all over the brain to be pulled, twisted and stretched.

The neurons send out signals through the axons to allow sodium and calcium to enter through the tiny pores on the outer skin that have been enlarged by the twisting and stretching. At the same time potassium is allowed to rush out of the neurons through the axon openings. The problem with too much sodium is that it also brings in water which can cause swelling of the axons and thus dangerously increase intracranial pressure. Calcium produces an enzyme that eats away at the internal structure of the axons.

Once the initial power surge is over, the brain immediately attempts to restore the equilibrium and get things back to normal levels. The first thing the neurons do is send a signal to pump potassium back into the axon and pump sodium back out. The potassium counteracts the effects of sodium by neutralizing its electrical charge. This process requires a lot of energy which is usually produced inside the neuron by something called the mitochondria, which acts like an internal power plant for each cell.

The mitochondria require fuel in the form of glucose to produce energy. Glucose is carried to the neurons by the blood flow in the brain. The demand on the cell for energy causes a drain on the supply which causes the brain to lose power and operate on a slower speed. The brain then demands for an increase in blood flow in order to bring in more glucose to the mitochondria to repair the damaged areas. However, the message somehow is disrupted and the blood flow to the brain is actually slowed down. No matter how many signals the neurons send out for more fuel, there is no increase in blood flow and the cells are in danger of dying. Because of this the brain releases high quantities of potassium in order to try to calm things down even more.

Since each dendrite or axon may be part of a communication line that carries impulses to thousands of nerve cells as it winds its way around the brain, any damage to a dendrite or an axon can impact many areas of the brain in the network other than just the area where the original damage was caused. This domino affect can cause symptoms that may seem unusual based on the point of impact, but neurons in one part of the brain connect to neurons in other parts of the brain and may be part of a communication link with many other functions.

This is why we often see a variety of symptoms when a person suffers a concussion. The damage can affect your cognitive, physical, emotional and psychological functioning and it can play havoc with your sleep patterns and relationships.



When the brain experiences a trauma, the body goes into an automatic emergency protection mode and a number of things take place that are designed to help the brain begin the healing process. However, it is this healing process that may actually put the student athlete in jeopardy if the proper procedures are not followed when an injury occurs.


Immediately following a brain injury where there is damage to nerve cells, dendrites and axons, along with some swelling of the brain, there is an automatic response by the body that results in a reduction of blood flow to the brain. While this may reduce internal bleeding if a blood vessel breaks, it also means that the damaged area of the brain is being deprived of oxygen and energy that it needs in order for healing to take place. This "energy crisis" makes the stretched or torn dendrites, axons and damaged neurons (nerve cells) extremely vulnerable and seriously impedes the healing process. In fact, studies have shown that a large number of neurons can die during this initial period because of the lack of oxygen and energy that result from the reduced blood flow. Death of a neuron is permanent.


Because of the swelling that generally occurs in the damaged area of the brain, the intracranial pressure may begin to rise slightly. In order to compensate for this dangerous increase in pressure the body reduces the amount of CSF present around the brain since this is the quickest way for the body to naturally reduce intracranial pressure. The brain simply drains out some CSF and does not replace it until the pressure is back to normal.

While this is happening, the reduction in CSF has a critical impact on the buoyancy of the brain. There isn’t as much CSF surrounding the brain as there is under normal conditions, therefore the net weight of the brain feels much heavier than the usual 25 g. Remember that the brain itself would weigh about 1500 grams (3 pounds) without the CSF. With the normal amount of CSF it would only weight 25 g because it is suspended in the fluid. This buoyancy effect is the reason why you seem to weigh less when you are swimming.


This reduction of blood flow and CSF is going on in your head, even as you are coming back to the bench to “shake it off” and recover from your immediate symptoms. The emergency response in your brain is going into overdrive and you may not even be aware of what is happening unless you begin to feel a bit of a headache or a bit dizzy.

Keep in mind that studies have shown that in up to 80% of the cases where a student-athlete has suffered a concussion, the student-athlete was not aware of any symptoms right away. So this could be taking place without you having any knowledge that you were injured in the first place. The headaches and dizziness may come minutes or hours after the injury.

With less buoyancy causing the brain to feel much heavier after an original injury, it is extremely susceptible to serious injury if the body suffers another blow and the brain suffers an additional trauma. Even a minor, seemingly insignificant blow to the body could result in a much more serious injury than the original blow because the much heavier brain will be hitting the inside of the skull and twisting with much more force because of the increased net weight.

On top of this, because of the original injury, the damaged axons have been stretched and become brittle. If there is another trauma that triggers an immediate surge in chemicals and electrical impulses through these stretched and brittle pathways, the pressure may cause the stretched and weakened axons to break completely and this will completely interrupt communication along those pathways.


This is why we strongly suggest that a student-athlete who has suffered what appears to be a serious blow that could have resulted in concussion should remain out of action for at least the rest of that day and reduce both physical and cognitive exertion until we can be sure of the extent of the damage.

Everything may seem fine on the surface and there may be no indication of obvious symptoms of a concussion immediately after the event, but inside the skull the body may have already taken necessary precautions as part of its emergency response, thus leaving the brain exposed to further and potentially much more serious damage.


This is why a “second repeat concussion” is often more severe than the original concussion. The original trauma may have stretched and damaged the axons and brain cells, but they may not have been completely broken. This means that even if their function has been reduced, they have not been discontinued. They can still operate in a reduced capacity and gradually they will return to their original condition and regain their flexibility. Eventually the flow of chemicals and electrical impulses will be able to reach their pre-injury levels and everything should be back to normal within a period of time.

On the other hand, if you don’t allow the proper time for healing and you don’t try to avoid overextending the damaged areas, you are taking a chance that the lines will burst, and then you are in serious trouble. There is no guarantee that you will ever regain full functioning in these areas if they are damaged a second, third or subsequent time.

What is even more frightening is that you could damage those injured areas simply by increasing the electrical and chemical impulses by watching television, playing video games, texting on the cell phone, or listening to music. You don't just need to worry about physical exertion. You also have to be concerned about cognitive exertion. You need to shut down all physical activity and you also must shut down your brain!



Most experts agree that about 80% of people who suffer a concussion appear to be symptom-free within 10 days to two weeks of getting the injury. However, and this is an extremely important point to remember, especially with our student-athletes, there is no consensus about whether subtle changes remain in the brain following those 10 days. Furthermore, we need to be especially concerned about the 20% of people whose symptoms do not go away within the first ten days. What is happening to their brains as they wait for recovery? What must we do to help them cope with what they are going through?

Therefore, when we speak of a student-athlete who has a concussion, we mean that the student-athlete is experiencing a complex process that is affecting the normal functioning of a part of his brain that may have an impact on many areas of his life. Our goal is to do everything in our power come up with a rehabilitation program that will make this truly one of those temporary conditions and prevent it from having life-altering consequences.


What many people fail to understand is that some of the symptoms may last much longer than others, and as we are going to find out, many of the symptoms of concussion do not produce obvious signs. In fact, many of the symptoms only show up much later and often as a result of a second blow to the body that transmits a force to the same area of the brain that was injured in the first place. This is why CMP will always take the position that once any sign, symptom or behavior consistent with concussion is observed or experienced, you must assume that there are other symptoms that you may not yet be aware of.

We all know that many student-athletes experience a competitive event where they are “dazed” and have their “bell rung”. After a couple of minutes of rest they may be able to “shake it off” and feel ready to go back into action. This temporary symptom may have resolved itself in a few minutes, but that doesn’t mean that the brain is totally recovered.

For example, symptoms such as headache, nausea, dizziness, vision problems, vomiting, loss of balance, confusion, feeling in a fog, ringing in the ears, and slurred speech may be evident and temporary. In fact they may appear and then disappear within minutes.

However, other behavioural symptoms may only be noticed over time, often over days or weeks. For example, decreased playing ability may have resulted from the injury, but those signs may not be evident right away, especially if the player is removed from play. Mood disorders, such as sadness, anxiety, irritability, aggressiveness and other inappropriate emotions may appear as subtle changes that are hardly noticeable at first and which may simply be passed off as normal reactions to being injured and out of action.

Cognitive signs may only be noticed when the student-athlete returns to the classroom or may only be noticed by parents/guardians during normal day-to-day activities. Being slower to react when responding to questions an having difficulty concentrating or remembering information are symptoms of serious symptoms that are on-going and which may take some time to resolve.

Sleep difficulties may only be noticed by parents/guardians and can easily be overlooked or passed off as other problems. A student-athlete who complains about being drowsy may seem normal unless it is about being more drowsy than usual. A parent will notice if his/her child is having trouble falling asleep or if he/she is sleeping more or less than usual. These are all signs of concussion symptoms that cannot be ignored.

Since a concussion is actually a “dysfunctioning of the brain” that is the result of a force to the head, even though the student-athlete may feel he has recovered physically, the impact of the blow may still be creating problems emotionally, intellectually and psychologically.


In fact, the number of people who seem to be more susceptible to repeat concussions once they suffer the first one gives rise to the theory that even once symptoms seem to be gone, there are still unseen vulnerabilities that may place the person at risk. In fact, the area of the brain that was originally damaged may end up being more vulnerable to future damage or the area may have weakened surrounding areas that end up becoming more vulnerable. The thing is - we just don't know enough about the brain to be certain. However, based on what we do know about the brain it is not surprising to find out that once you receive the first concussion it is much easier to get repeat concussions is absolutely true.


Experts also believe that many student-athletes may suffer what is referred to as subconcussions.

These are very minor injuries that do not produce any obvious symptoms, but over time if a person suffers enough repetitive subconcussions, the accumulative deterioration of the nerve cells and axons cause long-term changes in brain function that often appear in mid-life and have a significant effect on behaviour and personality.

Subconcussions may also weaken enough areas of the brain so that a full concussion is inevitable with the right amount of force. Since subconcussions are almost impossible to detect in that they produce no obvious symptoms, we should adopt the philosophy that if it is felt that a student-athlete suffered a hit to the body or head that "might have" produced enough force to the brain to cause a concussion, it very likely resulted in at least a subconcussion and warrants further investigation and monitoring.

Despite the fact that many experts believe that symptoms from a concussion are temporary, there is no doubt that as the recovery process unfolds the brain is extremely vulnerable to further trauma which may result in serious long-lasting consequences that go far beyond what we would call temporary. Therefore, the question remains: is a subconcussion a concussion? Are signs and symptoms necessary in order for the brain to be experiencing a concussion? Is a subconcussion simply a minor concussion? Can subconcussions be responsible for post-concussion symptoms? In fact, can a person have post-concussion symptoms without even being aware that he/she suffered a concussion in the first place? If he/she suffered a subconcussion instead?

The reality is that most adults have suffered from some traumatic brain injury at some point in their life. The injury may have come while playing sports or an accident. And anyone who has played a contact sport surely has suffered some degree of a concussion at some point in their playing career. So when a person claims to have never suffered a concussion it may just be that they were not able to identify the signs and symptoms of a concussion or that they had what we now call subconcussions where signs and symptoms were not obvious.


Statistics show that at least 10% of individuals with a concussion suffer post-concussion symptoms for months and years, especially if they were not properly treated after a concussion. And many others may have functional deficits that they do not relate to previous concussions and/or subconcussions, but nonetheless they do exist.

What we do know from research studies is that well after they have "recovered" from an injury, student-athletes who have suffered two or more concussions are more likely to report having concussion-like symptoms such as headaches, balance problems, sensitivity to light and noise, trouble concentrating and sleeping, irritability and nervousness than those student-athletes who only experienced one concussion or none.

Student-athletes with two or more concussions have also been found to be more likely to score lower on measures of attention and concentration and tend to do worse in school than those with one or no concussions. All of this points to the importance of having a solid concussion management program in place that will make sure student-athletes fully recover from each concussion before being allowed to return to play.


Researchers are learning more and more about the brain every year. They have now found evidence that the Frontal Cortex or as they are often called, the frontal lobes of the brain seems to be the most common region of injury from a concussion. Damage to this part of the brain can cause a wide variety of symptoms since the neurons found in the frontal cortex are involved in motor function, problem solving, spontaneity, memory, language, initiation, judgment, impulse control, and social and sexual behaviour. This is considered our emotional centre and is where we exhibit our personality.

Frontal lobe damage has been associated with reduced ability to perform fine motor movements and diminished strength in the arms, hands and fingers. Difficulty in speaking has also been common with this type of injury.

It has also been noted from studies that even when a student-athlete appears to have recovered completely from a concussion, there is evidence of a lingering interference with attention and memory, both which would impact tremendously on the ability of a student-athlete to handle the demands being made in the classroom.

So when we discuss the temporary nature of concussions or we talk about concussions completely healing, we cannot ignore the changes in social behaviour or personality that often follow a concussion. We tend to pass these changes off as part of growing up, or simply changes that were triggered by the injury, however, researchers may eventually find evidence that concussions actually change the course of a person's life and thus have permanent repercussions.

We must avoid the tendency to diminish the consequences of a concussion by stating that it is a mild traumatic brain injury that will resolve spontaneously. The explosion of neurotransmitters during the power surge in the brain at the time of impact may in fact result in permanent changes to the neural pathways and the synaptic architecture of various regions of the brain, such as the frontal cortex which is connected to just about every other area of the brain. The reorganization and rerouting of the neural pathways may bring a student-athlete to close proximity with pre-injury functioning, but changes may still exist and in fact the person may need to strengthen those reconfigured pathways all over again.


Adding to the mystery surrounding concussions is the fact that studies of athletes have shown that the amount of force and the location of the impact are not necessarily correlated to the severity of the concussion or its symptoms. This has lead to some confusion among experts about the amount of force that is actually required in order to cause a concussion.

Studies have also found that concussions occur over a wide range of impact magnitudes and that individuals have different levels of biomechanical concussion thresholds. A blow of a certain level of intensity that gives one person a concussion may not have the same affect another.

Furthermore, it has also been found that the injury threshold “within” an individual is dynamic and not at all constant. This means that a certain magnitude of impact will produce different results in an individual depending on the level of impact tolerance that person has at the time of impact. It changes with the day and the time of day.

There is a school of thought that if the injury tolerance is indeed dynamic in an individual, then this tolerance threshold may be influenced by the number of subconcussive impacts sustained by the athlete in the weeks or months prior to the impact that causes the concussion. Or that the longer a player participates in a sport, the more likely he is going to be concussed at some point in time because of the cumulative effect of subconcussive impacts. This will receive further study over the next number of years, but when you think of what happens to the pathways when they stretch after a trauma, and if you imagine these pathways going through the stretching and healing process a number of times, it makes sense that after a certain amount of stretching they would become weaker. The more often you stretch a balloon for example, the weaker it gets and eventually it will break.

It must never be forgotten that a concussion can alter the brain’s physiology for anywhere from hours to weeks, setting in motion a variety of events that interfere with the functioning of the neurons in the brain. The damage that occurs in most affected brain cells is usually reversed, but a few cells may die after the injury and some cells may take longer to heal than others. This is just something normal to expect.


By now you should now have a much better appreciation of what is at stake when it comes to managing concussions that are sustained by student-athletes. Every year we are increasing our knowledge base about the brain and how it works. Unfortunately, much of what we are learning is pointing out the errors we have made in the past when it came to dealing with sport-related head injuries. The challenge facing all of us today is to move forward, not in fear, but with care, choosing to implement protocols and procedures that err on the side of caution. We can no longer ignore the fact that any damage to the brain may produce life-altering consequences, changing the entire course of a person’s life.


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