Diagnostic EMGs, NCV, repetitive stim
 

Everywhere I read that an EMG is one of the first tests they might do for MG, right? (And the AChR.) A doctor told me that "if someone has an abnormal EMG they definitely do NOT have MG, they have MD." That's false right? I just want to make sure I am not crazy ;) I am pretty sure he was just trying to mislead me on purpose because he decided that I was just a silly hypochondriac... sigh. But it's still weird for him to make untrue statements.

With MG, you could have any combination of these 3 tests being normal or abnormal right? I am just trying to start to decide which of them I should get done - maybe 2 of them or all 3. (Doc will order the ones I want.) But yikes about the money and getting poked and prodded so much at once. (Well actually I think my ins might cover these 100%.)

Hi wonder,

welcome to the forum. I'm not going to try to answer this question at the moment, because my brain is a bit tired. I'm sure someone will be along shortley to you everyone here is very helpful and nice.
take care

From: http://www.netwellness.org/healthtopics/gravis/box2.cfm

The single-fiber EMG evaluates how well the nerve and muscle communicate. It involves insertion of a recording needle electrode into the area of the nerve-muscle communication point (the neuromuscular junction). There may be some discomfort with insertion of the electrodes (similar to an intramuscular injection, or a shot that goes right into the muscle). A single fiber EMG is often done on an eye, forehead, or forearm muscle. If a person is in remission, the SFEMG is normal, but if there is weakness from MG, the SFEMG is usually abnormal. Patients with ocular myasthenia will have an abnormal SFEMG. The diagnosis of MG is made after accounting for all the clinical symptoms and signs as well as the tests performed. Most patients tolerate the procedure well. A single-fiber EMG is a more technically difficult procedure than the standard EMG. Studies of this method suggest that it may detect abnormalities in over 95% of MG patients. However, other diseases may produce similar abnormalities. The test should be done by someone with extensive experience.

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Additional information can be found here: http://emedicine.medscape.com/article/1141438-overview

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Looks to me like your doctor was mistaken wrt the EMG. Was he a gp or a neuro?

hth

Brian.

I don't know, but I have been thinking that a single-fiber EMG is different from a plain EMG. Yeah, SFEMG is a lot more accurate than EMG in finding MG, as far as I know. But there's a lot I don't know!

Really good reminder -- Maybe I should get a SFEMG and skip the other tests.

He was a neuro.

I've not had an EMG and don't know if SFEMG is different from a plain EMG. Just doing web searches and reading the material available. From what I understand though there are surface and needle EMG's - it appears to me from what I've read that the needle EMG is the SFEMG.

Either way, EMG in general is supposed to be able to aid your doctor in distinguishing between the different types of disorders and clarify your diagnosis. http://www.stjohnsmercy.org/healthin...euro/TP012.asp

What sub-specialty on your neuro?
 

Wonder,
Unless you are a neuro-muscular specialty neuro yourself, I think it's potentially dangerous for you to be the one trying to figure out what tests you should have run, and what they may mean. I'm concerned that your neuro gave you faulty information for ANY reason, and hasn't forwarded you on to someone else him/herself.

As I've told many others here, Neurologist have sub-specialties in all different types of areas. Some specialize in MS and spend their researching efforts mostly in that area. Some specialize in vascular neurology (migraines and the like) and put their major efforts in that area.
Most may be familiar with all neuro conditions to a point, but have really only directed their continuing education at their particular area of special interest. I got this information directly from the neurologist that dx'd me with MG. She told me she could do the dx, but she isn't a good one to treat that disease because she specializes in Parkinson's. I am very grateful for her honesty and that tip!

There are SO many different neuro related conditions out there, many of them with overlapping symptoms, that you're having to try to figure out which tests to have to get a dx is akin to someone with no aeronautical training trying to figure out why a plane crashed!

Some of these diseases are much more serious and difficult than you can imagine, trust me - I have learned from hard experience - and most often, my neuro tells me, they see more than one in each patient.

I urge you to find a good neuro that specializes in the neuro muscular area of neurology and cares enough to pay attention to your entire list of symptoms without hinting that you are a hypochondriac.

And I would suggest you list ALL your symptoms, past and present, ALL tests that have been run (obtain copies of the reports and data for your files and to take to other doctors with you) and ALL medications, supplements and over the counter meds you are currently taken or have taken at any point for one year prior to your symptom onset.

If you need help finding a doc, there is a website where you can look up doctors by name or specialty, get ratings on them, find out how there school and current hospital affiliation rate - all kinds of stuff. This can be used to check out a current doc, or to find another in your area. Go to http://www.vitals.com/. It is a free search engine. Doing research to follow up with what your docs tell you is necessary and vital to your care, but we pay them a lot of money to help us, and we need to make sure we hire one that is earning that money!

Best of luck with your quest, but PLEASE remember that your future can be seriously impacted if you don't obtain the right diagnosis (or diagnoses as in most neuro situations). Let me know if you need any help.

The EMG and SFEMG are entirely different tests. I have had them both.
The EMG does use needles as well, but the SFEMG uses a different needle, but only in one place, roughly, and requires technique, and I have been told by some doctors that they will not do it as they are not experienced enough.

I think in order to get a diagnosis, I would try to get as many tests as I could, not as few, to determine if it was correct.

It is up to the doctor but I feel better having more than less.

Thanks. I agree, however, because of certain characteristics and because of past testing that comes back normal, it's hard for them to take my case seriously. It might just be something tricky to diagnosis like Lyme-related or 2-3 overlapping disorders. I suppose it's not unlike someone complaining that their computer sometimes gets too slow, but the computer repair guy runs all the benchmarks for days and it looks fine.

In web articles, it says SFEMG catches around 95% of MG and it says EMG catches around 80%, so that's why I was thinking only SFEMG. The docs would allow me to get these tests done, but they generally will not be able to advise me, because their advice is that I don't need any of them (and I need a psychiatrist or I just need to exercise, or some silly thing like that). But yes, maybe I will see another specialist at some point. (But then it will really look like I am a hypochondriac.) I'd rather learn more myself first.

Hi. I know how hard it is to get a diagnosis sometimes. I have some tips on that for you.

Have you ever taken photos of your face when you were rested and after you have done an activity (like out in the heat)? It is very telling. I have even gone so far as to line the photos up at the hairline, bottom of ear lobe and bottom of chin to "prove" the photos are the same size. I have then run lines across my before and after faces to "prove" there is drooping of my entire face. It's pretty shocking to look at. My eyebrows, nose and mouth all droop and it's an obvious change.

A neuro-ophthalmologist can assess whether or not you have fatigable ptosis (droopy eyelids). That's one more expert showing "proof" of something going on.

If you are short of breath, seeing a pulmonologist to see if you have neuromuscular weakness that is fatigable is important too. The MIP (maximum expiratory pressure) and MIP (maximum inspiratory pressure) show how well you breathe in and out. Besides just being lower than normal, sometimes the more you do this test, the more the #'s drop. Because in MG, you get worse with repetitive activity. My #'s have shown that on several occasions. Some neuros say that these tests aren't accurate because of "lack of effort" on the part of the patient. Bull hockey. I have done PFT's with the same clinic and they have reflected every single time how I am doing clinically.

I totally agree with these guys that this neuro may be out of his league. MD means muscular dystrophy. Not all MD's are created equally. MG is specifically weakness upon exertion that shows up on a SFEMG as a decrement.

The SFEMG may be the "gold standard" HOWEVER it relies heavily on the ability of the person doing it. There really are not a lot of true experts at doing the SFEMG; those who have done it over and over again and who have great technique. It doesn't "hurt" (but it DOES hurt) to do the EMG, RNS and SFEMG. It sounds like cost might be a factor for you though.

It is NOT hard to distinguish between MG and many other neuromuscular diseases, at least not if you are in the hands of a true expert. ALS may "act" like MG for awhile but not in the long run. Lymes is much different in presentation than MG.

And if you have obvious weakness, there is the Tensilon test. Not as many people do it anymore but it is still done. They inject the faster acting, short-lasting drug into your arm and watch for ptosis to improve. I think they should add to this by taking before and after photos of patients when they do it. Wouldn't that be more "objective" proof?!!!

I hope you will seriously consider finding a better neuro. You do not want to have tests, find out they're negative and then have to pursue help elsewhere. That can get even worse for you! Then docs can have an even worse view of your situation.

Whatever you do, I hope you can get answers. It's so frustrating not to know what is going on with your health.

Annie

Thank you.

I am not sure if I get ptosis or not. Same with other facial drooping. I may try to take pics. If I have it, it's mild apparently. I know parts of my face feel a lot weaker and people think I am almost sulky looking, but I'm just tired out there.

Yes PFT is something I am considering too. I think I'll eventually get one "just in case" it shows something, but I sort of doubt it will, and I am prepared for them to tell me that stuff about not putting in enough effort. I feel like if they were trying to test me, I would be exhausted in about 30 seconds and start to feel like passing out.

The neuro I saw was an expert in this stuff, but I think I was horrible about explaining my symptoms, and I think he really jumped to the conclusion that I did not have a neuromuscular disease. And he was very big on test results and I have a negative/clean EMG and NCV and AChR. However I have reasons to believe that my EMG and NCV results would be different if I did them again in the future, although I am not too sure of that. It seems to make more sense to do SFEMG or repetitive stim if I have those options (and LFT). Part of my reason is that EMG was testing the major muscles of my legs and I think they would only see the problem in other areas. I'm told they can test shoulders and wrists.