Why You Should Never Skip the Neck in Concussion Evaluation & Rehab.
Every patient with a concussion is a patient with a neck injury. Let me explain. A concussion results when the brain undergoes such rapid acceleration-deceleration that shearing and stretching of…
Rethinking Concussion Recovery: The Case for Active Rehabilitation Concussions are more than just a bump on the head, or “getting your bell rung”; they are a type of mild traumatic…
Introduction Appropriate concussion management is crucial for ensuring the well-being and long-term health of individuals who have experienced a mild traumatic brain injury. One aspect of concussion management that has…
How Hard is Too Hard? Examining the Forces Behind Concussive Impacts.
Introduction to Concussions A concussion (or mild traumatic brain injury) is a type of traumatic brain injury (TBI) that occurs when the brain experiences sudden movement or impact. This can…
Less concussions are generally better than more concussions but, when should an athlete retire? The answer to how many concussions is too many, is not that simple.
First, it’s important to understand what a concussion is, which is best explained visually.
To sum it up, concussion is a brain injury that results from acceleration and deceleration of the brain tissue. The acceleration causes the brain to stretch and sheer, which produces an excitatory and stimulatory response. When this happens, on a cellular level, millions of brain cells start to fire and burn energy. The end result is an energy crisis in the affected cells of the brain. Over the next few hours to days, someone who has suffered from a concussion will experience a continued drop in cellular energy.
During this energy low, the brain is extremely vulnerable. Any additional trauma to the head – even if the force is less – can cause another concussion. These second concussions are much more serious than the first and can potentially lead to permanent or fatal outcomes.
But here’s the tricky part – how you feel, has nothing to do with the recovery of the brain. You might feel great with minimal symptoms, but in reality, your energy levels are still low, and your brain is incredibly vulnerable to additional trauma. This is why proper management, and not simply relying on symptoms to guide return to sport decisions, is so important.
It may not be the number of concussions that you get, but rather how you recover between each one that matters most.
Research on animals has demonstrated that if subsequent concussion injuries are sustained AFTER full recovery from the energy deficit, the cumulative effect of these injuries is lessened or even abolished all together (1,2).
Studies on this metabolic phenomenon was introduced with Christopher Giza’s landmark work, The Neurometabolic Cascade of Concussion (3) . Since then, much of this research has been pioneered by a group in Italy who started with mice (2,4) . They found that in a mouse, concussion results peak at an energy low at about six to fifteen hours after injury, and it takes about five days to get back up to baseline levels (5).
The next study by Vagnozzi et al., then looked at multiple concussions in mice. This study found that if there was a full five-day recovery between concussions, there was no cumulative or additive effect(2). However, if a second concussion occurred on day three, the two brain injuries added up, and the result was the same energy lows as a severe TBI. In addition, 10% of the mice died as a result of Second Impact Syndrome at the 3 day interval.
Next, researchers moved on to human studies (6,7). It was discovered that humans went through the same process of energy reduction and restoration however this process took about six-times longer in humans than in mice – between 22 and 45 days to recover. Interestingly, and concerningly, symptoms had all resolved within the first 2 weeks of injury, but it took between 3 & 6 weeks for the brain to actually recover significantly and get out of the vulnerable period.
This, once again, highlights the fact that relying on symptoms to determine when you are safe to return to your sport, is completely inadequate!
Feeling better does not signify that your brain has fully recovered.
A few athletes in this last study didn’t wait for the study to be over, and instead returned to their sport early – and got another concussion during their vulnerability period. In these cases, it now took three to four months to recover. In other words, after one concussion, brain recovery happens between 3 and 6 weeks however, sustaining a second concussion prior to this full recovery resulted in a 3 to 4 MONTH recovery.
Do we have a concussion problem? Or, do we have a concussion management problem?
So back to our original question, how many concussions is too many? To provide the most appropriate answer, further questions must first be asked.
As a rule of thumb when making a retirement decision for an athlete, ask two main questions:
1) Is each concussion that someone is getting, resulting in longer and longer recoveries?
2) Is each concussion happening with less and less force?
If the answers to either of these questions are ‘yes’, then an athlete should likely consider stopping contact sports. Potentially, they are caught in a perpetual period of vulnerability, where previous concussions may have been mismanaged or they were cleared to return to play far too soon. This could explain, as discussed above, reasoning for becoming concussed with less force and for taking longer to recover.
If the answers to these questions are no, there are again further questions to be asked. In 2018 Davis-Hayes at al., published an algorithm that works through a decision tree, which can be a helpful guide to discussions with athletes and patients when deciding to retire (8). If you are having these conversations with parents and athletes, please be sure to check out this algorithm.
As you can see, the question of how many concussions is too many, is a difficult one to answer as there is no magic number. It may depend on a variety of factors that all need to be taken into consideration. Please consult with your healthcare professional to have these conversations.
Complete Concussion Management is a network of clinics and trained practitioners that provide evidence-informed concussion care and 6 stages of concussion recovery for all those impacted by concussion. We may have a clinic near you.
What are the 6 stages of concussion recovery?
There is no one-size-fits-all approach to concussion recovery. The best way to recover from a concussion is to rest, avoid activities that make your symptoms worse, and follow your doctor’s instructions.
The six stages of concussion recovery are:
Acute Stage (0-7 days): This is the time immediately following the concussion. Symptoms are typically at their worst during this time and may include headache, dizziness, nausea, vomiting, fatigue, difficulty concentrating, and memory problems.
Subacute Stage (7-21 days): Symptoms begin to improve during this time, but some may still be present. It is important to rest and avoid activities that make symptoms worse.
Recovery Stage (21-90 days): This is the time when most people make a full recovery. However, some people may experience lingering symptoms, such as fatigue, difficulty concentrating, and memory problems.
Return to school or work Stage (90-180 days): This is the time when people can start to gradually return to their normal activities. It is important to listen to your body and take breaks as needed.
Return to sports or other activities (180-365 days): This is the final stage of recovery. It is important to be cleared by a doctor before returning to sports or other activities that could put you at risk of another concussion.
Long-term follow-up (>365 days): Some people may experience long-term symptoms after a concussion. It is important to see a doctor if you have any concerns.
It is important to note that everyone recovers from a concussion at their own pace. There is no set timeline for recovery and some people may experience symptoms for longer than others. If you have any concerns about your recovery, please see a doctor.
Complete Concussions specializes in collaborative, evidence-based concussion care. Our evidence-based training programs and integrated healthcare technologies empower multidisciplinary teams to implement standardized care for those impacted by concussions.
Our network and patient database enables large-scale research to advance concussion management, and ultimately, the long-term health and well-being of concussion patients and also teach them some concussion care at home.
We analyze leading research to develop best-in-class approaches to concussion care.