Epilepsy Foundation

Mostly summarized from the textbook 'The Clinical Neurophysiology Primer', by Blume & Rutkove, 2006.

While slowing is considered an abnormality, it's important to remember that it's one of the most common EEG findings. It's not necessarily indicative of seizures, though it is often present in people with temporal lobe focal seizures.

Focal slowing suggests a problem, but doesn't really say what problem. It could be from a tumor, an infarct, or it could be because the person has just come out of a seizure or is having a migraine. (Yes, migraines cause focal slowing.) Even hypoglycemia or hyperglycemia (low or high blood sugar) can sometimes cause focal slowing.
The biggest thing that is relevant in intermittent slowing is the speed of the wave. The slower it is, the more serious a problem it indicates. If there are continuous bursts of slowing, (It's weird, but that's how they say it. Bursts of slowing merely mean it comes out of the blue, then goes away.) this can suggest eleptogenic focus. (oh, yes, there's the word - it can say the slowing is from epilepsy.)
If the frequency of slowing is rhythmic or shows "frequency evolution," epilepsy is also the most likely reason. Frequency evolution means the slow waves speed up and slow down over and over, but don't speed up to normal during that episode of slowing. Epilepsy is even more likely as the culprit when the focus of the slowing is in the temporal area. (Either of the temporal lobes can be sneaky little brats with this one, the fact that it's a temporal lobe acting up is a major indicator for E.)
So, you might ask, what does slowing look like on an EEG? (Okay, maybe you wouldn't, but I did, so here's a pic.) You can click on either picture to get a larger version.

And here's a normal one: (Can you tell the difference? heh. Good luck.)

Tags: eeg, eleptogenic, focus, slow, slowing, waves

Views: 30122

Replies to This Discussion

Great!
Once the kids are off to school, I will reread this and hopefully and then look at Owen EEG's reports! Then maybe I'll have a better idea!

Seriously I was thinking to my self yesterday, and wondered if intermit slowing could be the blips we see in Owen? Too me they look like subtle CP seizures!

I will explain in detail later!!

Thanks Isky!!
Eventually I'd like to get a book on EEG abnormalities.

I still don't have a good idea s to what slowing means and have not found good info explaining it (haven't looked that hard though)

Ava has a big scar on the right side of her brain from stroke.
Her EEG is considered very abnormal due to almost continuous spiking on right (makes sense)
but also severe slowing on the left.

I guess I don't get the severe slowing on the left as her focus of course is on the right.
Structurally, the left hemi looks fine, or at least it did on her MRI .... course she was only six months so I suppose things might look different.

Even with this very abnormal EEG, you wouldn't know. Neuros and epi's are often surprised or seem to be, by her level of function.

So Isky, what do you think Ava's slowing might mean?
Ok Isky - you asked and the only difference I can see from the Normal EEG below and the Abnormal EEG above is:

61 year old patient, (I might be wrong) has waxing and waning, with Delta slowing and with paradoxical waves in the frontolobe region; which is showing me a possibility of a patient having possibility of AD or PD but not necessarily that of "epileptogenic". <--- AHA! But this is suggestive if I was an "electroencelphalographer" of a possibility that this "may" be from the "Cortex" region rather than the Frontolobe region hence the 75 hertz slowing, and I would put in a recommendation for a repeat EEG to see if we can capture this repetitive behavior again. If we are able to capture such behavior, then the chances are - the patient very well may be suffering from focal seizures.


<---- waiting to get a big fat red F from Ry.

*laughing*
The primer book I mentioned is very good. It's about neurology in general, but has an entire section on normal and abnormal EEGs. I got it used and in very bad shape for $30 on ebay, but you can read quite a bit of it from Google books.

If you haven't used Google Books before, toward the lower right, there's a "search in this book" area. You can't just read the book whole, you have to search for things. Try entering intermittent slowing, and hit search. The first book I'm posting is to give you an idea of what Snippet View looks like. It's almost useless, except it can help you get keywords to search on Google's main page for more information. The second book is the one I was referring to. It has a limited preview, so you can actually read a lot of pages. Some books will only allow three or four pages. A few I've seen had more than 100. It's up to the publisher to decide, so it's hard to tell what you'll get. You can read quite a bit of the book I used to write this post.

Here's one all about EEGs.
And here's the one I used.
LOL. Actually, you're pretty close to right, except he doesn't have seizures. He has dementia with the accompanying hallucinations and delusional states. I argue these states are more similar to temporal lobe focal seizures than most people want to admit. His slowing is generalized, actually, so it's not focal to any specific part of his brain, and unfortunately for him, it is constant. :(
This is called continuous diffuse slowing. My grandma's EEGs would display a similar pattern. This is a level of dementia that tends to revert people to childlike behavior, and inability to care completely for themselves, and a very small ability to create new memories.

Southie ( Sharon ) said:
Ok Isky - you asked and the only difference I can see from the Normal EEG below and the Abnormal EEG above is:

61 year old patient, (I might be wrong) has waxing and waning, with Delta slowing and with paradoxical waves in the frontolobe region; which is showing me a possibility of a patient having possibility of AD or PD but not necessarily that of "epileptogenic". <--- AHA! But this is suggestive if I was an "electroencelphalographer" of a possibility that this "may" be from the "Cortex" region rather than the Frontolobe region hence the 75 hertz slowing, and I would put in a recommendation for a repeat EEG to see if we can capture this repetitive behavior again. If we are able to capture such behavior, then the chances are - the patient very well may be suffering from focal seizures.


<---- waiting to get a big fat red F from Ry.

*laughing*
Structurally, I have absolutely no abnormalities on my MRI. We've pretty much pinned down my seizures to being left temporal lobe from the symptoms and some abnormalities that show up when I have strong SPs, but both side of my brain show intermittent slowing. My frontal lobe does every once in a while, too.
It doesn't require any sort of damage to create slowing. I would guess hers could be because that side of her brain is having to work harder to take over the tasks she once did with the other side of her brain. Her neuros may be shocked at her function level, but they shouldn't be. Brains are very plastic. We can remap things as needed... and she's very young. At 6 months, her whole brain is active and hasn't begun pruning off branches of synapses she doesn't really need yet. She's in the "always on learning mode." So, there's a lot of her brain that can be used to compensate for the damage. It would have had a much greater impact on her if it had happened at 40, because by then, we've already pruned off things. But even then, she could have relearned much of her previous function. I think we often sell our brains short. They are amazingly adaptable.

jjbeck said:
Eventually I'd like to get a book on EEG abnormalities.

I still don't have a good idea s to what slowing means and have not found good info explaining it (haven't looked that hard though)

Ava has a big scar on the right side of her brain from stroke.
Her EEG is considered very abnormal due to almost continuous spiking on right (makes sense)
but also severe slowing on the left.

I guess I don't get the severe slowing on the left as her focus of course is on the right.
Structurally, the left hemi looks fine, or at least it did on her MRI .... course she was only six months so I suppose things might look different.

Even with this very abnormal EEG, you wouldn't know. Neuros and epi's are often surprised or seem to be, by her level of function.

So Isky, what do you think Ava's slowing might mean?
Isky (RyAnne Fultz) said:
LOL. Actually, you're pretty close to right, except he doesn't have seizures. He has dementia with the accompanying hallucinations and delusional states. I argue these states are more similar to temporal lobe focal seizures than most people want to admit. His slowing is generalized, actually, so it's not focal to any specific part of his brain, and unfortunately for him, it is constant. :(
This is called continuous diffuse slowing. My grandma's EEGs would display a similar pattern. This is a level of dementia that tends to revert people to childlike behavior, and inability to care completely for themselves, and a very small ability to create new memories.

Southie ( Sharon ) said:
Ok Isky - you asked and the only difference I can see from the Normal EEG below and the Abnormal EEG above is:

61 year old patient, (I might be wrong) has waxing and waning, with Delta slowing and with paradoxical waves in the frontolobe region; which is showing me a possibility of a patient having possibility of AD or PD but not necessarily that of "epileptogenic". <--- AHA! But this is suggestive if I was an "electroencelphalographer" of a possibility that this "may" be from the "Cortex" region rather than the Frontolobe region hence the 75 hertz slowing, and I would put in a recommendation for a repeat EEG to see if we can capture this repetitive behavior again. If we are able to capture such behavior, then the chances are - the patient very well may be suffering from focal seizures.


<---- waiting to get a big fat red F from Ry.

*laughing*

So what do I get? A "C"? considering I am NOT a Medical Doctor nor an Electroencephalographer either!

From IskY:
"It would have had a much greater impact on her if it had happened at 40, because by then, we've already pruned off things. But even then, she could have relearned much of her previous function. I think we often sell our brains short. They are amazingly adaptable."

This is a different and wonderful topic.
I am a firm believer in neuroplasticity. Yes, Ava's brain has learned to re-route or "reorganize".
She has gained a lot in terms of function (which I believe has helped some w/ sz control).
Even when the older stroke pt strokes and is severely impaired, his brain to can learn to reorganize.
With the proper treatment anyway.

But back to slowing, do you have any thoughts has to why Ava might have that severe slowing in the left hemi, while near continuous spiking in the right?
Neither effect her as much as we were warned they could.
She functions quite well.
I gave my theory on the slowing. I'd guess the spiking is from the damage in the right lobe.
A lot of people get slowing and spiking in the same area, and while there may be no overt damage, that does mean the area has a problem - slowing is a bigger problem than spiking, from what I can find on the topic. Spiking isn't all that abnormal. So, why does she have spiking? Well, almost anyone could. Think of that like asking "Why does one person react more emotionally to irritation than another?"

jjbeck said:
But back to slowing, do you have any thoughts has to why Ava might have that severe slowing in the left hemi, while near continuous spiking in the right?
Neither effect her as much as we were warned they could.
She functions quite well.
A lot of people get slowing and spiking in the same area,

Right, but Ava has the severe slowing on the left and the spiking on the rt.

The spiking in Ava's case makes a whole lot more sense ... she has all that damage to the rt hemi.
I understand the spiking on the rt... I just don't understand the slowing the left.
If the slowing was on the rt .. I'd get it, or if she had spiking on the left, I might get that too.
But to only have the severe slowing on the left is confusing to me.

One thought is this.
A few years ago we saw a wonderful ortho surgeon. He suggested Ava's leg issues looked more like a diplegia than a hemiplegia from stroke. So I have wondered if maybe Ava has some PVL.
hiya everyone!

Thanks for posting that Isky!! Doctors don't always feel the need to explain EEG results, well least mine doesn't.
An EEG that I had done in 2004 was done a few hours after having a sz. When I went into my neuro's office they wanted to do the EEG on the spot. As the eeg person (who also reads them) was hooking me up, I told him that I had a sz earlier and that I had a migraine..so that he was aware of it. Now, when my neuro got the results, he said it was abnormal due to sz activity. That was actually NOT the case. I get copies of any/all results of test that anyone does (which I highly recommend for everyone!). Obviously a regular person trying to read an eeg report is just well, gibberish for the most part! lol so I googled all the medical terms. Imagine how suprized I was when I got all that done and was able to make sense of it, and came to find, yes my neuro was correct that it was indeed abnormal, HOWEVER, it was NOT due to sz activity! Every single thing that was talked about in this report referred to my having a migraine at the time of the test.
Finding that out upset me (even though I was glad it wasn't showing sz activity "at that moment") because my neuro made me believe that is was due to sz activity and it wasn't... AND there was something recommended to the neuro and he completely disregarded it. (keep in mind, my last MRI was in 2000!!!)
actual impression: "The diffuse slowing in this recording suggests mild bilateral cerebral dysfunction. This particular finding is not specific with regard to etiology. Most common causes would include toxic/metabolic,infectious or degenerative encephalopathies.The intermittent regional left frontotemporal slowing suggests a focal neuronal disturbance involving the anterior aspect of the left hemisphere. The possibility of a lesion should be considered. Clinical and imaging correlation is recommended. This recording DID NOT SHOW EPILEPTOGENIC ACTIVITY."
I'm curious to why my neuro didn't follow the recommendations...or was it that he didn't bother to read the entire report!?
I suffered with complex parital seizures for over 25 years before having a right temporal lobe lobectomy. It's been almost seven years now and so far so good! I had a eeg done about a year ago, and it showed seizure activity on the right side of my brain. I haven't had a seizure so I have no idea why it showed activity, however I do deal with terrible migraines. My migraines are on a daily basis now, I've tried so many meds to control them and so far no luck.

Do you think that the eeg can pick up when your having a migraine? it seems for alot of people that epilepsy and migraines go hand in hand, which was always the case for me. I have conquered the seizures now I need help with the migraines they are trying to take over my life and I'm not going to let that happen!

I currently take zonegran 75mg to try to ward off the migraines so far not working. I also take 200mg lamictal a day, and probably will stay on that for the rest of my life, but that's ok.

Blessings to you all,

Cindy

RSS

Terms of Service Update 6/4/2012

We have updated our Terms of Service for eCommunities Groups.

Events

July 2014
SMTWTFS
12345
6789101112
13141516171819
20212223242526
2728293031
       

© 2014   Created by EF Admin.

Badges  |  Report an Issue  |  Privacy Policy  |  Terms of Service