For the boffins - please advise
 

Hi,

I have just received my test results from my consultant . On the SFEMG which I have always been told was negative I found this in the report -

- I performed a single fibre analysis of the right orbicularis oculi collecting over 20 units. Apart from one unit which showed borderline excess of jitter the other units demonstrated a normal MCD.

How many Jitters does one need to show !

In another report of a sfemg the Dr states

- Repetitive nerve stimulation was performed on the right median, the right ulnar, right peroneal, right tibial, right accessory, , left facial recording from the nasalis muscle, right facial recording from orbicularis oculi muscles. A repetative nerve stimulation "showed no significant decrement" in any of the nerves tested.

So what is significant and there had to be a small jitter to show no significant decrement.

Anyway over to you guys

Love
Rach

Rach
Jitter shows up when you have MG, I have had this since the beginning. I am not sure of the levels of jitter.My neuro had just said it shows up when you MG at some point. Now I show jitter, plus neuropathy & myopathy, but that is an overlap disease showing up. I guess when the jitter is there they are not alarmed because it just confrms again what we are diagnosed with !
Mary

Hi Mary,

Thanks for your reply.

My point is Im being told I don't have MG!!! But I have a Jitter! I have always been told sfemg are negative for jitter yet one showed up. I wanted to know how many jitters make it positive! Or do they just change the rules of the game to suit themselves?

Thanks again
Rach

Yes. I have a positive SFEMG, but negative EMG (mutliple ones, I tried really hard for that LOL) and so they say I don't have it by most doctors. It all depends on the doctor. Isn't this fun?

rumpled
 

I can think of things that are more fun LOL!!

Your post made me smile.....thanks

Rach

Rach, What's a boffin? ;) Is it someone silly, cause then I can respond.

The Single Fiber EMG is a hard test to do. Even someone who has done hundreds can have a hard time doing it. And then it takes about two hours to analyze. So you not only have to do the test well but to analyze it well.

A borderline jitter would be indicative of a problem. Did you have the test done while on any meds like steroids or Mestinon? If so, it would make the test negative. Some people with MG are so bad that they can be on meds and have a positive SFEMG though.

From what I know from an MG expert, a borderline result would and should push a doctor's thinking in the direction of MG IF there is other clinical evidence supporting that diagnosis.

People with MG are diagnosed without a positive EMG. It's a clinical diagnosis backed up with positive tests. And a negative test doesn't prove anything.

I'm sorry you have not heard back from Dr. Vincent. And I'm really sorry these doctors don't have the faith in what they are seeing to help you.

Annie

Annie
 

Hi,

a boffin is someone who is extremely intelligent and knows there stuff about a paticular topic. It was tongue in cheek but its failed to translate. I was after responses from people like yourself, who have a wealth of knowledge that I have only scratched the surface on.

From what I have read I think that 10% of the whole test has to show a jitter for it to be classed as a positive test.

for the August and October tests I was on prednisolone. However on the August one it said I showed no significant jitter.

For the March one Id been off prednisolone for 3 weeks and for all the tests I abstained from mestinon for 24 hours before the test.

Thanks for your reply

love
Rach

Rach
So sorry you have to go through this frustating crap, I know how you feel though, I got my MG diagnosed, now am going through loads of testing for my overlap. The testing never seems to end, & the worst is, they never tell you everything, they keep notes until it adds up to something, or they mention what they think it is, & take it back next visit ! Thats always a good one.
Take care,
Mary

Hi, A study should be considered abnormal if greater than 10% of fiber potential pairs exceed normal jitter or have impulse blockade, and/or mean jitter exceeds normal limits.
Based on this standard your test was indeed "normal"
Hope that clears that up.

When my neuro did my SFEMG, we already knew I was seroneg. She did the SFEMG and at one point said, ' I hate it when this happens. MG is supposed to be a jitter of 6 - 10 and you are only 5.7. But I don't care - I know you have MG and I'm going to treat for it.'

So exactly what the measurement is, I don't know - - but I remember she said it should be 6 - 10 for and MG diagnosis.

Hope this helps a bit - - I'm really sorry you are having such trouble with dx.
Sue