When the computer goes wrong

Tuesday, July 31, 2007

The brain is an impressively wired computer, storing information from inputs through our five senses and sifting through the data, getting rid of frivolous material, organizing the important stuff into short term memory centers and finally rearranging the final product into long term memory. The brain also sends messages out electrically to the rest of the body, controlling movement and position so that the body can take the brain where it wants to go. Electricity is the key and sometimes it short circuits.

Seizures occur when parts of the brain becomes irritable and develops electrical surge. That surge can remain in a small area or it can spread to the whole brain. Normally, when we lift an arm, it is because part of the brain sends an electrical message through the spinal cord for the arm to move. When the whole brain fires, the whole body moves and the classic shaking of a seizure is witnessed. Usually the shaking is short lived, because the brain doesn’t like being irritated and it shuts itself down.

Every person has the potential to have a seizure. Usually the seizure threshold is high and there needs to be an outside noxious stimulus to cause an electrical surge that is greater than that threshold for a seizure to occur. Seizures are often seen after head injuries and high fevers in kids can precipitate a seizure. In some people, the seizure threshold is set lower and they may need medication to raise that threshold to prevent seizures.

After the seizure, it takes time for the brain to reboot, just like you computer. When it reboots, you can type as much as you want, but until the programs are ready to go, nothing is going to happen on the screen. Similarly, the brain needs time to reset itself and this post-ictal phase shows up as a confusion, sleepiness or irritability.

Chief Justice Roberts had a seizure yesterday (he also had one in 1993) and we’re told that his doctors couldn’t finds cause. So what were they looking for?

When a seizure occurs, the usual suspects are rounded up? Was there an infection that may have caused irritability? Did part of the brain lose blood supply due to stroke or was did a tumor or mass cause the problem? Screening blood tests and CT or MRI scans of the brain may be helpful in sorting things out. One of the most important tests is an EEG or electroencephalogram, sort of like an EKG of the brain. By looking at the brain’s electrical activity, the neurologist can sometimes find a short circuit focus.

The problem with seizures is not the one that was just completed, but if and when the next one might occur. Seizures are a common problem and many people have an isolated, single event. For that reason, if all the tests are normal, people are given a freebie: one seizure, no treatment, just watching to see what the future will bring. But if seizures recur, then treatment is necessary for prevention.

It’s hard to predict the future in the watching phase, so recommendations for limiting activities are important. People who have had a seizure don’t drive or scuba dive or jump out of airplanes or put themselves into positions where another seizure will put themselves or others into danger. The restrictions may last weeks or months depending on the situation.

For Justice Roberts, it is good news that no cause for seizure was found. Decisions on further treatment, medications and activity will be tailored to his situation, just like any other patient. And just like any other patient, the expectation will be for him to return to a fully active life at the level where he was before the seizure occurred.

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