How/why does my brain not work properly?

August 15, 2009 6:13 PM

I have idiopathic epilepsy and I'm trying to understand it better. I suffer from tonic-clonic siezures and I need some help understanding (I know idiopathic means the docs don't know why) what's happening and why.

I have many questions falling into four different topics.

1) Is there any reason why depressants/anti-psychotics control my siezures besides the fact that they just do? Secondly is there any reason why stimulants do the same thing when they seem to do the opposite of most seizure control drugs?

2) Can anyone offer a more accurate description of what happens in a siezure other than "my brain just shorts out"?

3) Is there any clear insight (or even probably hypotheses) as to how an epileptic brain is different from a healthy brain (for example, when they give you an MRI what are they looking for?)?

4) Why do I forget things like who I am, where I am and how I got there for the first 30 minutes after the siezure?

posted by Pseudology to science & nature (6 comments total)

My father was diagnosed 43 years ago with idiopathic epilepsy that has been resistant to treatment. I've been with him in GPs', neurologists', and epileptologists' offices; in hospitals; and as he has undergone countless EEGs and MRIs. I've been there as his doctors have tried different drugs and drug combinations (one of which resulted in a status epilepticus episode), and for his latest treatment which is showing a great deal of promise, the implantation of a vagus nerve stimulator.

Over the years, we've heard many variations on "we don't know why." It's frustrating.

I'm not a neurologist, but absolutely the most important thing you can do is to get a very good one, ideally an epileptologist. He/she can work with you to give you answers (as far as can be done) for your questions.

In April of this year, Newsweek did an excellent cover story on epilepsy. Start there for background on what is known about what is going one when you have a seizure. A search on the term 'epilepsy' at their web site brings up these results. One of the points made in the Newsweek cover story was that as many people are diagnosed with epilepsy as are diagnosed with breast cancer, but because epilepsy has been "hidden," it is not so well understood medically.

I don't have an answer to your first question: there are so many anti-seizure medications out there that one can't really divide them simply into depressants/stimulants. Your doctor should be able to tell you why he/she has prescribed a particular drug or combination and give you some idea of what it is doing.

MRIs can show damaged parts of the brain (my father's MRI shows damage to the left front temporal lobe). Additionally, other conditions that may cause seizures must always be ruled out before attributing them to epilepsy, even after a diagnosis of epilepsy has been made. I.e., stroke.

Regarding your last question: after you have a seizure, you are in a state called post-ictal. The amount of time you are in this state is related to the severity of the seizure.

My father has had a full, active, and otherwise healthy life with epilepsy. But it's been like any other hard-to-understand, hard-to-control illness (think Type I diabetes): it requires a lot of work on both the patient's and the doctor's part.
posted by apartment dweller at 7:18 PM on August 15 [3 favorites]

Here is the link to the Newsweek cover story.

And here is a link to the Epilepsy Foundation, an advocacy organization which has much information on understanding seizures, medication, and other issues. Also, there are forums on many topics here.
posted by apartment dweller at 7:29 PM on August 15

1) Lots of medications fit into those classes, but most likely they help control seizures (or increase the risk of seizures) because of receptor cross-talk. Wellbutrin can increase the risk of seizures but of its interaction with multiple receptors in the brain. Conversely, people taking Lamictal for depression are taking a drug originally studied in epilepsy. Tjhe short answer is that many drugs in the brain are not _that_ receptor-specific to avoid hitting other targets unrelated to what they are prescribed for.

2) A seizure is a change in the type of brainwaves that normally occur so that part (or all) of the brain is under-going synchronized nueronal firing. So if you see someone having twitching in their right thumb and it starts spreading up the whole arm, you're watching one tiny part of brain with seizure actiivity spreading to surrounding areas and therefore causing the broader area of twitching. That's the abbreviated version: coordinated, synchronized abnormal brainwave activity. If it involves cognition centers, you can lose consciousness or at least awareness (is in an absence seizure).

3) Often a typical MRI could show nothing. But there are things on an MRI that could help explain a seizure -- swelling, a tumor, a malformation of a part of the brain, etc.

4) As the previous poster said, that's a post-ictal state. It's almost universal among people who have a seizure that involves loss-of-consciousness. There's usually some retrograde amnesia, as well as amnesia of the event and for some time after. Typically it recovers over a few minutes to an hour, but at the very last folks are usually quite sleepy afterwards.
posted by davidnc at 7:31 PM on August 15

I have idiopathic epilepsy myself. (Complex-partial seizures, probably originating in the frontal lobe.) So, yeah, I can relate. Feel free to MeMail me if you ever want to commiserate on how you have to take more meds to combat the side effects of your meds! Or that having seizures just sucks.

1) The drugs that you're taking that you qualify as "anti-depressants" are actually, most of them, anti-convulsants that have an anti-depressant effect, not the other way around. Lamictal is FDA approved for epilepsy with off-label usage for bipolar disorder, f'rinstance. The drugs work on neurotransmitter imbalances and have a general stabilizing effect - both in terms of lowering the seizure threshold and generally stabilizing mood. This is lucky coincidence since epilepsy and depression often go hand in hand (and not just because epilepsy is kind of a downer).

2) During a seizure, your neurotransmitters send signals to your neurons that all say "HEY! Guys! I have a great idea! Let's all fire at THE SAME TIME!" Now, this is going on all the time. Everyone has a seizure threshold. The problem with epilepsy is, that the bar is set really, really low. Say, instead of needing six beers to get drunk, your neurons only need one. So, your neurons get all hepped up and say "OH WOW! OK! I'M FIRING!" and they all do this at the same time, which your brain interprets as "Oh shit. I don't know what the hell. Fuck it. I'll seize." Same thing happens with any electrical circuit. Think of it like an old apartment. In a more modern place, you can run the AC and the microwave and the toaster and everything's jake. In an older place... you run the AC and turn on the microwave and then the whole system gives up.

3) There is very little insight into what a "normal" brain looks like in the first place. What they're looking for on an MRI are structural abnormalities of any kind. Any. They'll take it. If they can find a gnome eating a cheeseburger in there, they'll be psyched even if no gnomes have ever caused seizures before. Tumors are a big concern as they can certain cause seizures and then various other problems as well, up to and including death. Scarring from previous injuries or infections can cause seizures. Congenital defects such as a enlarged gnome-secreting gland are also potential seizure creators. My MRI has shown a few abnormalities, which have just made neurologists say "Huh." That's really the most definitive I've ever heard a neurologist be, actually.

4) The post-ictal state is kind of like the brain rebooting. Wikipedia covers it pretty well. Interestingly enough, the post-ictal state is the only thing that all flavors of seizure have in common. You and I have very different seizures, but we have the same post-ictal state. (Though mine doesn't involve sore muscles from the tonic-clonic action, but yeah, I forget where I am and sometimes even *who* I am.)

Feel free to MeMail me if you have any more questions. I've been living with seizures for eight years now, so I totally sympathize with trying to figure out what the hell it is that your brain is trying to do to you.
posted by grapefruitmoon at 8:53 PM on August 15 [4 favorites]

I'm going to give some very simplistic generalizations:

So you hear a lot about neurotransmitters like dopamine, serotonin, norepinephrine, etc. The truth is, these represent only a very small fraction of the chemicals being shot around in your brain. The vast majority of neurons in the brain utilize glutamate and GABA (mostly the former), which are the two fundamental excitatory and inhibitory neurotransmitters.

Your brain exists in a delicate balance between excitation and inhibition. Too much excitation and your brain has a seizure. Too much inhibition and your brain goes into a coma. People with epilepsy have brains that are too easily excited. Oftentimes this is due to a specific area of the brain that, for whatever reason, is overexcitable. A seizure is like applause in a crowd. It starts in one area; sometimes it spreads, and sometimes it dies out into awkward silence. If the problem area is loud and insistent enough, it can get all the other neurons clapping, and then you're down on the floor convulsing. That's bad.

In severe cases, they can actually remove the problem area with surgery. But obviously, this is a treatment of last resort. The preferred method is to essentially train the area to be less excitable. They do this with anticonvulsant drugs, which limit the ability of neurons to become overexcited. Over time, the problem area calms down. The longer you go without a seizure, the less probability you'll have one in the future.

Other drugs, besides anticonvulsants, can also raise or lower the seizure threshold. Those other neurotransmitters I glossed over work in more subtle ways, but they can still have very profound effects on the way the rest of the brain is functioning. The exact method through which they do this depends on the drug in question.

As for why you forget things after a seizure, that is not a simple question to answer. Different time frames of memory are represented very differently in the brain. Generally, the longer-lived forms of memory are encoded in more stable forms—represented, for example, by actual structural connections between neurons, which take time to build and are less likely to be affected by moment-to-moment activity. More immediate forms of memory, like what happened in the last few hours, will be encoded in less stable forms, like chemical modifications occurring at recently-activated receptors, or in the activity of second messengers or genes that have been triggered by said receptors. The even shorter forms of memory, such as what happened in the last few minutes, will be present in still more volatile forms, such as actual electrical activity essentially being looped around in your brain.

A seizure is an overwhelming surge of electrical activity spreading across your brain, and it wipes clean a lot of the less stable forms of memory. So, until all the areas of your brain can regroup and start comparing information—to rebuild a working model of where and who you are—you’re going to be fairly confused.

Apologies to the neuroscientists who are no doubt rending their garments in frustration at the glaring omissions and simplifications employed in this explanation.
posted by dephlogisticated at 10:08 PM on August 15 [3 favorites]

Hey everybody, thanks for the responses and certainly more are welcome.

Apartment Dweller: I have a great epileptologist. He's retiring in a year or so and is trying not to see any new patients but when I arrived at his office and he found out the meds the Neurologist was giving me the reaction was practically a full facepalm (he gave you WHAT!?). I only started getting my siezures under control when I started seeing this guy. I'm making this post because it takes months to book an appointment and I realized a few weeks ago that I'm going to need to know enough to make sure the the next doc I get doesn't fuck up.

Grapefruitmoon: "Let's all fire AT THE SAME TIME!" Perfect explanation. It helps me understand the why behind the memory loss Which brings me to...

dephlogisticated: I carry a a first-year university psychopharmacology text which makes a perfect stepping stone for more complicated neurology. It's really REALLY limited but it does explain things like GABA, Glutamate, action potential, etc. in plain English complete with diagrams. I just can't find anything, even in bookstores/internet that explains neurology any better.
posted by Pseudology at 3:46 AM on August 16