You do not have to get knocked out to have a concussion.
Most of us have seen an athlete go limp and fall on the field after a hit. An easy assumption can be made that the athlete has suffered a concussion. However, what about the athlete who is still standing after a big hit? Or the one that gets up right away? Can these situations mean that they did not sustain a concussion? Well, the answer is not that simple.
To understand this further, we need to discuss some neurology and physiology. Remember running around as a kid or an adult and having a “runner’s high”? During that time did you ever have a fall or scratch yourself? Most likely, you did not notice the pain from the fall or scratch until your “runner’s high” had worn off. The same can happen with shock that comes right after an accident. You might not feel pain for hours after the event.
Well, there is a particular part of the brainstem the stimulates a little organ on your kidneys called your adrenals. This stimulation releases the hormones, Epinephrine and Norepinephrine. These two hormones are released into your blood stream and transported to other areas of your body. The release of these hormones is what signals a “flight or fight” response in the nervous system. The hormones help your body get the energy to your muscles quickly. Also, Norepinephrine temporarily decreases your perceived pain. When we are in immediate danger, our brain wants to keep us out of harm’s way and alive. When we are finally safe, those hormones decrease and our rest and digest nervous system kicks in. Once this process happens, we begin to feel pain and present symptoms.
A limp reaction after a hit means a nerve has been significantly damaged. If the nerve damage is less but still there, then the hormones (Epinephrine and Norepinephrine) are still running through the athlete’s bloodstream assisting their nerves and muscles to work. This is why we may not physically see an immediate response to damage in the nervous system.
It is important to know that when you are hit in the head, your brain gets torqued around in your skull. A simple hit to the body can also cause the same torque. The torque happens because the brain is only suspended in fluid inside your skull and is not actually anchored down to anything. So, imagine wringing water out of a washcloth with a twisting motion. When you do this, it is the inner part of the washcloth that has the most torque put upon it. Well, your brainstem would have a similar torque put on it with a hit to the head or body. The torque happens and causes micro tears in our nerves and blood vessels. Unfortunately, a torn nerve will not function the same. Athletes who go limp right away are a sign that bigger tears have happened in their nerves.
However, some athletes might not realize they have sustained any trauma to the brain during a practice or game. This is a result of endorphins and adrenaline running through the body. Therefore, it is important to address “subconcussive” (micro tears) hits in football, other sports, or jobs. The concussion may not be completely obvious but there can still be damaged neurons.
A properly diagnosed concussion explores measurements of change in brain function. These measurements include eye movements, balance, and other neurological tests or imaging. Baseline testing is recommended for athletes every season to have a standard comparison. There may be many things that can change brain function but in a short time during a few months season it makes it easier to assume it is from trauma sustain during a sport. It is a clinical decision. Symptoms might even start gradually and present as pain or changes in cognition and personality.