Post-Concussion Fatigue – Brain Injury Battery Drain

Post-Concussion Fatigue – Cumulative Cost of Over Attending

By Gordon Johnson

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Post-Concussion Fatigue is what happens when the brain’s batteries are drained by running too hot from overwhelming the brain’s attentional capacity. Yes, the brain can be run “too hot” when its attentional demands are overwhelmed. Think about this example:

I own an Iphone. The latest version’s batteries have seem to have finally caught up with the increasing demand of the newer and faster versions of all the apps I leave open, even though I rarely use most of them. But the one app that I must close when not using, is my GPS app. When open, it not only rapidly drains the Iphone’s batteries, it actually makes the phone hot to the touch. My theory on why the phone gets hot is that it is not only doing significant computational and networking activities constantly as I reposition the phone on the planet, it also has to create visual images of each new location I relocate my phone to, every few seconds as I drive down the highway.

As discussed earlier, any program, whether it is a human based program like the vestibular system, or a phone app like the Iphone, will use more attentional resources, any time it processes visual data. The more I use my phone or my brain’s attentional resources, the faster the energy resources are depleted. Likewise, keep several programs, with dozens of windows open on my laptop when it is not plugged in, the faster the batteries run down.

When it comes to energy resources, the brain is like a portable electronic device. It has a finite amount of energy it can consume before it tires. The two biggest common denominators in terms of long term symptoms after Mild Traumatic brain injury are headache and post-concussion fatigue. Post-concussion fatigue is the net result of over-attending problems, because of reduced neuronal efficiency after brain injury.

To fully understand post-concussion fatigue, you must remember these important lessons we have covered earlier:

Concussion damages the brain’s connectivity, by injuring its axons/axonal tracts;

A poorly connected brain is an inefficient brain, meaning it takes more time and more concentration, to do even simple tasks;

Other symptoms of brain injury, (anxiety, depression, neurological deficits and pain) also demand attention and make concentration more difficult, requiring more energy; and finally;

Concentration requires energy, which energy has limits.

The net result of all of this is that post-concussion fatigue dramatically reduces how long a brain injured person can focus and concentrate. Where even highly trained professionals could work 8 to 10 hour days at a high level, after brain injury, that ability to concentrate can be reduced to as little as 2 hours. Often times, pure cognitive intelligence is almost unchanged by a MTBI. The the ability to apply that intelligence in work related tasks may be severely limited. The more I have to concentrate to attend, the quicker I will tire. Take the analogy of how you feel after a difficult exam:

I was probably as tired from any cognitive thing I’ve ever done as I was when I finished taking the Law School Admission Test (LSAT). The reason is that the LSAT required me to focus my attention so intensely. While not a long period of time, the four hours of the exam is a really substantial period of time to fully attend. That’s the kind of concentration is required after a concussion, not to take a extremely important exam, but just to get through every day, every conversation.

Unfortunately, post-concussion fatigue comes on faster, any time stress is added to the mix. Stress, like other emotional functions such as anxiety and depression, consumes attentional resources, quickening fatigue. That is another reason a really important test like the LSAT will fatigue so thoroughly. Concentration is so intense, because it is so important.