Concussion: What’s Really Happening & the Importance of Baseline Testing

Written By: Dr. Patti Farrell – BA(Hons), DC

With all the attention in the media surrounding concussion over the past few years, it is no secret that this has been a ‘hot topic’, specifically in sports. There are many questions surrounding concussions. People often wonder, what defines a concussion? What are key symptoms of a concussion and what is actually going on in a concussed brain? In addition, when do we really know when an athlete is ready to participate in full-contact sport without risk of further injury? Hopefully all of those questions will be answered in this post. Let’s start off with the definition of what a concussion is and what occurs at a physiologic and metabolic level in our brain:

A concussion, or a mild Traumatic Brain Injury, is a defined as a series of complex pathophysiological processes that occur in the brain as a result of traumatic forces placed upon our head or body. With a concussion, there are often no significant findings on imaging, such as MRI, CT, or X-ray. This is because the symptoms that an individual experiences after a concussion are frequently due to functional and metabolic disturbances in our brain, as opposed to an actual structural injury.

Signs and symptoms of concussion include, but are not limited to, headache, fogginess, pressure in the head, dizziness, sensitivity to light, sensitivity to noise, irritability, and sleep disturbance.

Historically, it has been said and believed that concussions usually heal within 7-10 days, and a symptom free individual or athlete will be cleared for full contact return-to-play within this time frame. More current research however, states that the pathophysiological processes in our brain are not fully recovered within this time frame, despite an individual feeling asymptomatic.

Follow along with me for a few moments as I explain what is happening in the brain when a concussion occurs. In our brain, we have ‘neurons’, which are the functional units of our brain. Every time we think, move, talk, etc, neurons fire, allowing us to achieve these processes. In order for neurons to communicate with each other, there are a series of processes that need to happen, which require energy, otherwise known as ATP.

When an individual sustains a concussion, all of the neuron’s in our brain fire at once, giving initial symptoms such as dizziness, ‘seeing stars’, headache, among others. These symptoms will usually last approximately 15 minutes before subsiding. This often happens during a sporting game when an athlete gets hit, feels a bit dizzy or has a slight headache for a few minutes, and then is cleared to go back in the game because they ‘feel fine’.

HOWEVER this is just the beginning of a series of those complex processes I was talking about. Since all of the neurons are firing at once, the energy demand for our brain has greatly increased in order to achieve a normal balance.  In a healthy brain, 2/3 of the body’s ATP production is needed to maintain a balance. This is where things become problematic; the initial blow to the head or body causes all of the neurons to fire at once, which overloads our primary ATP generating system, causing it to shut down. Similar to a generator in a power outage, our bodies now have to rely on back-up systems that are far less efficient. In order for this back-up system to function, an increase of blood flow to the brain is needed. This poses another problem because after a concussion, blood flow to the brain is decreased, making this system even less efficient than it already is. Blood flow has been shown to decrease by 50% in animals after impact, thus we can only imagine how it is affected in humans.

We have now reached an energy crisis – there is a huge increase in demand for energy in our brain, and a large decline in the supply. This is why we do not want to physically exert athletes if they have any symptoms in the acute stage, as exercise will increase their body temperature and ATP usage, prolonging recovery and increasing their symptoms. As you can see, this is a fairly complex process and it usually takes between 2-4 weeks to fully recover. Thus, despite individuals’ asymptomatic claims after 7-10 days, this is not a good indicator of brain recovery due to the complex metabolic recovery processes still occurring.

This is also why rest at the initial stage is crucial. After a period of rest, we can further conduct testing to determine the extent of blood-flow abnormalities, as well as cognitive, and physical impairments. This is done by gradually exposing the athlete/individual to cognitive and physical tasks that may bring about any signs or symptoms. Full contact clearance would be achieved through a gradual step-by-step process, to ensure that the athlete is cleared at the proper time without any risk of additive brain injury.

If athletes are immediately cleared and re-join the same game in which they sustained the injury, or are even sent back too early while their brain is still recovering, there is a risk of a second impact, which can lead to irreversible damage in the brain and fatality. Unfortunately, this has happened on several occasions with young athletes. Rowan Stringer was a 17 year old female rugby player that suffered a fatal brain injury after being tackled. Following her death, reports stated that in the prior week, though out several games, she had been hit twice, resulting in headaches for which she only required Advil. At the time of impact however, she was asymptomatic! In addition, research shows that athletes returning to the same game after sustaining a sport-related concussion take twice as long to recover compared to those who are removed. They also have significantly worse neurocognitive performance, and greater symptoms present at one week and 30 days post-injury.

This leads us to our next point…the importance of baseline testing. Baseline concussion testing consists of a variety of tests that evaluate numerous processes (memory, cognition, strength, balance, reaction time, visual processing) that may be affected by a concussion. As previously mentioned, even if an individual is ‘symptom free’ it does not mean their brain has fully healed, and this is where baseline measurements are truly helpful. Having a battery of different tests, and a baseline comparison when athletes are healthy, allows us to detect dysfunctions that we may not detect otherwise just from simply asking an individual about their symptoms. For example, grip strength tests the body’s ability to recruit motor units for muscle contraction, which are commonly effected after a concussion, notably in children. The King-Devick test examines visual tracking and processing speed, which have also been shown to be significantly impaired in concussed individuals. Postural sway and control have also shown to be hindered following symptom recovery in individuals. There is no one perfect test to identify a concussion in athletes, which is why multiple tests are used and needed to reveal any abnormalities. The more tests we use, the higher the sensitivity is for detecting concussion. Once an athlete has achieved or surpassed their pre-injury baseline in conjunction with other tests, it is safe to assume that they are fully metabolically recovered to participate in full-contact sport without additive risk if another concussion is sustained.

It is crucial that if you think you have had a concussion, or if you have any symptoms, to tell your coach/teacher/parent and visit a healthcare professional within 24-48 hours for proper management and education on what to look for and what further steps to take. At Leaps and Bounds, we are a certified Complete Concussion Management clinic, with certified CCM practitioners. CCM is a program based on the best up-to-date, evidence-based management surrounding concussions. We understand the importance of concussion management and the risks involved when an athlete is cleared too early. We feel it is important to educate players, parents, coaches, and teachers on this topic and believe that proper management includes communication between all parties involved to ensure an athlete is receiving the care they deserve. For more information about this program, concussions, and baseline testing, please visit http://www.completeconcussions.com/

 

1. MYTH:  You need to get hit in the head to have a concussion 

A concussion may occur from a direct blow to any body part with an impulsive force that is transmitted to the head

 

2. MYTH: You need to have a loss of consciousness to have a concussion

Over 90% of concussions do not have a loss of consciousness

 

3. MYTH: All concussions happen in contact sports

Sports such as cheerleading, rodeo, and soccer have some of the highest rates of concussion

 

4. FACT: Seizures following concussion are not necessarily a bad thing

If a seizure happens directly after a hit, it is usually benign. If a seizure happens after the injury, further investigation is required

 

5. MYTH: “I should take Advil or Tylenol for my headache immediately after a concussion”

Drugs may mask true symptoms of concussion and make it difficult to assess if a condition is worsening and may increase risk of bleeding. However, it may be applied for a specific prolonged symptom such as sleep disturbance, or anxiety

 

6. MYTH: “I do not need to visit a health care provider (chiropractor, physiotherapist, medical doctor, etc.) following a concussion”

Make sure to visit a health care practitioner that is knowledgeable in the area of concussions within 24-48 hours. They will examine the individual and rule out any sinister pathology, as well as educate each party involved on concussions and the return-to-learn/play process.

 

7. MYTH: “I got hit in a game, had a headache for 10 minutes, then it went away and I felt fine. I’m not concussed and I don’t need to tell my coach or parents”

Any concussive symptoms after a hit should result in immediate removal from the game with no return. Be sure to tell the coach and parents about any symptoms experienced following a hit and get checked by a healthcare professional!

A recent study compared neurocognitive performance, symptoms, and recovery times between athletes that had continued playing vs. those that had been removed from play after a sports-related concussion

Results showed that the group that continued to play exhibited significantly worse neurocognitive performance, and greater symptoms compared to those that had been removed.

They also took longer to recovery (avg 44 days vs 22 days)

 

8. FACT: Helmets and mouth guards do not prevent concussions

Helmets have shown decrease incidences of skull fractures but not concussions; mouthguards have shown decreased dental and facial injuries, but do not have an effect on concussion risk

 

 

References

 

Daneshvar DH et al. Helmets and mouth guards: the role of personal equipment in preventing sport-related concussions. Clin Sports Med. 2011 Jan; 30(1): 145.163.

Elbin RJ. et al. Removal from play after concussion and recovery time. Pediatrics. 2016 Sept; 138(3): doi: 10.1542/peds.2016-0910

Leddy J., Baker J., Kozlowski K., Bisson L., Willer B. Reliability of a graded exercise test for assessing recovery from concussion. Clin J Sport Med. 2011; 21(2): 89-94

Leddy J., Hinds A., Sirica D., WIller B. The role of controlled exercise in concussion management. Am Acad Phys Med Rehabil. 2016 Mar; 3 Suppl: (S91-S100).

Marinidez Z. et al. Vision testing is additive to the sideline assessment of sports-related concussion. Neurology: Clin Pract. 2015 Feb; 5(1): 25-34.

Signoretti S., Lazzarino G., Tavazzi B., Vagnozzi R. The pathophysiology of concussion. Am Acad Phys Med and Rehabil. 2011 Oct; 3(10 suppl 2): S359-368.

Sivak S., Nosal V., Bittsansky M., Dluha J., Dobrota D., Kurca E. Type and occurrence of serious complications in patients after mild traumatic brain injury. Bratisl Med J. 2016; 117(1): 22-25.

Vagnozzi R., et al. Temporal window of metabolic brain vulnerability to concussions. Neurosurg. 2007; 61(2): 379.389.

 

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