Brain fog after a concussion is one of the most common and long lasting concussion symptoms. The same 3 causes of brain fog are also the roots of many other post-concussion symptoms. When people talk about brain fog, they often just call it fatigue. Brain fog associated with mild traumatic brain injury goes well beyond simple fatigue. While the body may be fatigued as well, this overwhelming lack of energy is from the brain being tired.
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It is difficult to describe brain for after a concussion. Part of that is the fact that it may be difficult for you to explain anything post-concussion, but the main reason is that it is not a relatable state. That sense that there is a disconnect between how fast events are happening around you and the slow pace of your mental perception, comprehension and response is not generally experienced by people who have not had a head injury. Feeling as if there is some kind of mental obstacle between your perceptions and reality, that there is a certain lack of immediacy, just is not had in every day life. This is a true reflection of how your brain is functioning on a physical and biochemical level. Perhaps the best way to explain it is something like an extremely bad hangover, but even that falls short.
Brain fog after a concussion can make it difficult to do plan and carry out tasks. This is a reflection of how your frontal lobe is being affected. The frontal lobe is responsible for executive function. This executive function usually applies to planning something new or planning a series of things to do. For example, it could be simple like planning out your day or more complex like breaking down a big project into interdependent steps.
But post concussion brain fog goes well beyond planning novel task. It can make it difficult to do even simple everyday tasks. You may find it difficult to go through daily routine tasks. When I was at my worst, I found it difficult to take a shower. It was like I had never done it before and it was like that every day for a long time.
Here are the 3 causes of brain fog after a concussion:
Brain Damage from Concussion
Number one: The nerve connections that hold the programs for even our most routine tasks are broken. This is a result of the brain actually moving within the skull upon injury. The distance between nerve cells required for them to communicate with each other is very specific. When concussed these neurons can get pulled or twisted to the degree that they don’t connect well to the neurons around them. If neurons are actually torn, they die. Cell death can also occur later due to inflammation.
The result of these lost connections is that we have to think about everything. “How do I get dressed?” “Where do I get off the highway to go home?” We have to struggle to remember or re-learn these simple things. Having to think about everything is exhausting. However, each time we think about doing something and do it, we are making new nerve connections which eventually will coalesce into a new “program” for that activity. That process takes time and energy.
Overstimulation post Concussion
Number two: The medical term for this is Neuroexcitotoxicity. It’s a mouthful, but the word actually provides a good explanation of what is happening. Nerves, your brain cells, are in a toxic enviornment, which excites them. Not the happy kind of excitement. This excitement means that they fire more easily.
Nerves really only do one thing, they fire. To fire, they need a stimulus. On a chemical level, injury produces inflammation in our brain. That inflammation causes the individual nerve cells to fire with less stimulation. Are you sensitive to light or sound? This is why. Smaller stimulae seem bigger to the inflamed brain. Because the nerves are firing more with less stimulation they can’t recover so they fatigue.
We also have trouble filtering stimulae. Normally the brain has an idea of what is meaningful and what is not. The injured brain has a hard time with that so it tries to pay attention to everything. Have you ever been unable to concentrate because of some small insignificant sound like a faucet dripping or kids playing outside? Every time your attention is pulled in a different direction, energy is spent.
Brain Inflammation and Brain Fog
Number three: Neuroinflammation impedes our brain cells ability to produce energy. Every cell contains little power plants called mitochondria. These guy convert either glucose or ketones into ATP the fuel every cell in our body uses. Brain inflammation damages mitochondria. What is worse is that when we become over-tired, it creates more inflammation in our brains and that hurts them energy even more. This comes at a time when the energy demands on the brain are very high because it is trying to heal.
Maybe you have had this experience: You are tired, mentally and physically. You are trying to get something done, maybe just reading this. The longer you work on it, the harder it is. That’s you, using the last of your energy reserves. You’re almost done or you’re under a deadline, so you push on. The work gets sloppier and you get more and more frustrated. You either finish or give up in complete defeat. The next day you have zero energy. Doesn’t matter how long you slept. You can’t even look at what you were working on the day before. The thought of it alone is mentally exhausting. After 3 solid days of rest, you recover to the energy level you were at before pushing through on that work or, if you don’t rest, you just keep spiraling down until you collapse into a forced rest.
This is why it is so important not to get over-tired and keep enough reserve energy so your brain can use it to re-build the energy making system of your brain. For this I recommend using coping strategies and consciously managing your energy.
Rest and Concussion
Every concussion protocol starts with rest. Some end there, yours will not, but rest must always be a part of your plan to heal. If rest was the answer, you would not be reading this. That being said, how to rest the brain is a little different than what we typically think of as resting. There are activities like reading, or watching screens that might be distracting and restful otherwise, but actually demand a fair bit of work from the brain.
The Brain Fog after a concussion Meter
As you can see; the 3 causes of brain fog after a concussion run deep. There are a lot of physical and chemical processes involved. These processes relate to many other symptoms. Brain fog is actually considered a major indicator of brain inflammation. Oversensitivity is the main indicator of neuroexcitotoxicity, but brain fog would be a close second. In terms of damage to brain cells, brain fog might be considered more of a side effect. With that in mind, the level of your brain fog can be a good indicator of your overall brain health after concussion.
In my article Tracking Progress in Concussion Recovery, I write about the emotional importance of tracking your symptoms. Brain fog is probably high on your list and some degree of brain fog may be one of your longest lasting symptoms from concussion. Because it reflects so many aspects of overall brain health and healing from mTBI, it is an excellent symptom to track. You can have your own brain fog meter and rate your brain fog from 1 to 10. In the short term, spikes in brain fog might give you insight into your triggers. As you progress, you should see your brain fog lessen over time.
