False positive on emg?

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False positive on emg?

Postby LKP1231 on November 4th, 2014, 3:20 pm

This is probably a stupid question. I know so many worry that their negative emg is incorrect and to me it seems like it's never wrong as it's very sensitive. Has anyone heard of the positive ones being wrong? Like spontaneous activity or insertional activity? I guess probably not, I suppose a sensitive test like that is pretty accurate. Especially done by a trained neuro. I was just hoping it might not be as abnormal as it seems.
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Re: False positive on emg?

Postby RIno468 on November 4th, 2014, 3:44 pm

Did you get a positive EMG?

Last i recall yours was deemed clean by medical professionals ...

I could be wrong...
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Re: False positive on emg?

Postby LKP1231 on November 4th, 2014, 4:08 pm

I'm not going to go into the details again but what I was told was fascics was misleading info by the neuro. It was evidence of denervation (which he told me when questioned as if it were the same thing) but both he and the neuromuscular doctor are suggesting that based on my MRI it is being caused by back issues. There are still some very gray areas with the explanation so I was just wondering if since so many doubt the clean reports, and they seem to be quite accurate, is it possible anything could be misinterpreted with actual abnormal results. I probably don't want to know the answer
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Re: False positive on emg?

Postby RIno468 on November 4th, 2014, 4:41 pm

If an EMG gave a false positive then I am sure a Doctor would dig deeper into it as it would show up.

You have to remember your fear (ALS) is a disease of exclusion -- in your case -- the doctors believe that your issues may be caused by your back -- thus making that an inclusion, meaning that you are safe.

i know its hard -- i fall from time to time (reading these *beep* tongue twitch posts have made my tongue go twitchy today but im trying not to let that freak me out) ---

BUT -- stand back from the fear and emotion and look at the facts that you have:

1) no real clinical weakness
2) Dr's are not concerned about ALS
3) EMG results pointing AWAY from ALS
4) MRI has shown possible issues with your back which can be causing some of your current symptoms
5) you are hypersensitive and anxiety at a real high

Those are 5 VERY VERY strong cases that would lean towards you NOT having this dreaded disease.

Always remember, that its not that people doubt the reports per se, but the fear of them being "the one" who goes from BFS to ALS overrides any logical thinking process with clear evidence they have that points AWAY from it.

But to answer your questions, as far as I know and as far as I have read... I have never read or heard of any false positives of an EMG.
Last edited by RIno468 on November 4th, 2014, 5:19 pm, edited 1 time in total.
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Re: False positive on emg?

Postby LKP1231 on November 4th, 2014, 5:12 pm

Ok thanks. You bring up good points and I figured false positives especially done by the neuro himself wouldn't be too common
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Re: False positive on emg?

Postby trustme78 on November 5th, 2014, 11:03 am

LKP1231 wrote:This is probably a stupid question. I know so many worry that their negative emg is incorrect and to me it seems like it's never wrong as it's very sensitive. Has anyone heard of the positive ones being wrong? Like spontaneous activity or insertional activity? I guess probably not, I suppose a sensitive test like that is pretty accurate. Especially done by a trained neuro. I was just hoping it might not be as abnormal as it seems.


I remember reading on here that some neuros refrain from performing an EMG after a clean clinical with people younger than 40. The reason was "because of the damaging effect of a false positive". In my opinion an EMG is highly subjective because age related effects show up for example.
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Re: False positive on emg?

Postby bobajojo on November 5th, 2014, 11:20 am

First of all, an EMG is not "highly subjective", that's just a ridiculous statement.

Secondly, I had insertional activity in all muscles tested. I didn't know it until I requested a copy of my EMG report. I called the Mayo Clinic and they said it is something that just comes with neural hyper-exciteability. Still benign. I bet lots of you all reading this post had it too, especially the ones who twitch head-to-toe all day, everyday.

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Re: False positive on emg?

Postby LKP1231 on November 5th, 2014, 11:25 am

I had that too along with spontaneous activity and reduced recruitment. Wish I'd never seen the results
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Re: False positive on emg?

Postby trustme78 on November 5th, 2014, 12:49 pm

bobajojo wrote:First of all, an EMG is not "highly subjective", that's just a ridiculous statement.


Watch your language please. Calling someone's statement ridiculous is uncalled for and a little harsh. Everyone is entitled to have an opinion. I got this opinion based on the conversations with my neuros. I didn't say that an ALS dx is subjective, I said that the interpretation of the EMG results is subjective.

Reasons for this statement:
a very experienced doctor of neurology did my EMG. A less experienced neuro was there too and he explained certain things to her while I was present. He actually mentioned that he had been doing this for decades and that you get a lot of experience after doing this hundreds of times. It's not a blood test with a borderline value with no room for interpretation.

Second reason: My gf had a nerve velocity test yesterday (same machine they use for emg testing). She has problems with her right hand. She has visited two neurologists over this before - they always tested the right hand and got normal values. The doctor yesterday tested her left hand as well and found out that her left and normal hand has very low numbers which put the values of her right hand (actually arm) into the abnormal zoNe.


I hope no one reading this ever gets an unclean EMG but my opinion is that a good clinical is the key. And I think it even happened to people here that two neuros interpretated an unclean EMG in different ways. I would always get a second opinion when a neuro says that an EMG is not clean.

Take care
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Re: False positive on emg?

Postby Bibi on November 5th, 2014, 1:37 pm

The neuro Who ordered my EMG , Said that EMG often shows " something" Wrong and not so clear answers , so he hesitated to send me for one , but did it anyway.
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Re: False positive on emg?

Postby Pascal35 on November 5th, 2014, 4:09 pm

I agree with the majority of the statements here.
Some neurologists misread some spontaneous activity. Is it fibs or just movement...?
There you need an experienced guy to clear the air.
Of course in polyphasic motor units and high/low amplitude i think it is more objective so probably there wouldn't be mistakes.
In my opinion you should always double check a positive EMG if there are no findings in the MRI consistent with the EMG findings.
In your case i think you should trust your doctors. If you have an issue in your back (proven with the MRI) you will have those findings in every EMG. So you shouldn't worry
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Re: False positive on emg?

Postby bobajojo on November 7th, 2014, 10:02 am

trustme78 wrote:
bobajojo wrote:First of all, an EMG is not "highly subjective", that's just a ridiculous statement.


Watch your language please. Calling someone's statement ridiculous is uncalled for and a little harsh. Everyone is entitled to have an opinion. I got this opinion based on the conversations with my neuros. I didn't say that an ALS dx is subjective, I said that the interpretation of the EMG results is subjective.

Reasons for this statement:
a very experienced doctor of neurology did my EMG. A less experienced neuro was there too and he explained certain things to her while I was present. He actually mentioned that he had been doing this for decades and that you get a lot of experience after doing this hundreds of times. It's not a blood test with a borderline value with no room for interpretation.

Second reason: My gf had a nerve velocity test yesterday (same machine they use for emg testing). She has problems with her right hand. She has visited two neurologists over this before - they always tested the right hand and got normal values. The doctor yesterday tested her left hand as well and found out that her left and normal hand has very low numbers which put the values of her right hand (actually arm) into the abnormal zoNe.


I hope no one reading this ever gets an unclean EMG but my opinion is that a good clinical is the key. And I think it even happened to people here that two neuros interpretated an unclean EMG in different ways. I would always get a second opinion when a neuro says that an EMG is not clean.

Take care
Volkmar


Do you know what I think is uncalled for? Irresponsible statements from someone with no neurological experience that will make people wonder if their EMG was misinterpreted and keep them in the "cycle of fear" when the reality is that the EMG is extremely sensitive and accurate and if it says your fasciculations are benign, then your fasciculations are benign. So please, watch your own statements. Keep in mind that the people reading them are going through a very difficult time and are looking for reassurance. But after reading your statement, they are now going to question their EMG results.
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Re: False positive on emg?

Postby LKP1231 on November 7th, 2014, 10:21 am

IVE TRIEDTO DELETE TGIS THREAD BUT DONT KNOW HOW. This was not meant to scare folks with clean emgs. I was hoping mine was not as bad as it seemed. If anyone knows how to delete the post please do so
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Re: False positive on emg?

Postby TwitchyDoc on November 7th, 2014, 11:02 am

EMG really can produce false positives, although the probability is very low. Anyway, it would never produce findings that can be confused with MND, except for maybe some inconclusive clues that can be then incorrectly interpreted in the context of the clinical exam.

Saying that "EMG is highly subjective" is like saying that "Interpretation of the X-ray is highly subjective", it is a nonsense..While more experienced neurologist might be able to get better readings (or get them faster) due to years of practice etc., the interpretation should be the same, i.e. skill-dependant.
If there are fibrillations, positive sharp waves or other signs of abnormal electrical activity, the EMG will detect it - there is no space for any subjective judgement. It is either there or it is not, unless the doctor puts the needle somewhere else or gives you wrong instruction (like 'flex' instead of 'relax'..). Sure the interpretation is something else but in general, EMGs cannot be subjective - there is no magic in the EMG, it is a simple oscilloscope.
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Re: False positive on emg?

Postby Bibi on November 7th, 2014, 11:19 am

Hi twitchydoc
Can i ask You A quistion ? I have dystonia ( writers cramp ) in my Right hand , i have had it for 14 years , it was finally diagnosed by EMG about 4 years Ago. The neuro Who did The EMG While i was writening Said it was easily to see that i have dystonia in that hand. I didnt ask for any detail and was not worried about it , i Can still do my work as A laboratory technisian. My quistion is : do You know if it is possible to see The difference in EMG between dystonia and other things ?
My neuro did not want to do an EMG in my Right side because of The dystonia.
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