Electromygraphy Test and Antibody test, % of positve in Test

  : : I have all of the classic symptoms of MG and have had 9 pstosis surgeries.
  : : I was at the MDA for testing and still have to have the anitbody test and
  : : biopsy done this month. I was wondering which test I had.  After coming home and reading the two different tests for MG I am not sure which one I had.  It was normal but they are doing other tests for MG.  The test I had consisted of 5 repetative jolts in a row and numerous times, done on my ulnar nerve and again in my shoulder.  I was told that the test only ment I was normal for yesterday so it could be different if done at another time.  Is that true, and was this the RNS test or the SFEMG?  What does a lab biopsy test show, and I also read that antigen may not be present in someone even if they have MG?  
  : : I was told that the tenisilon test would not be an indicator of MG on me because I have already had corrective surgery.  The own neuro I am seeing in November, not connected to the MDA has me scheduled for only the tenisilon test.  Even though we know I may not show visual results for the technician to see, will I personally feel the improvement on my muscles if I still have this test done?  Could it help me feel improvement in my own muscle strength to justify having this test for my own self reasurance?  If I do feel improvement is that an indicator the mestinon may help me feel better and allow me to regain some of my strength back?
  : : Thank you for this wonderful forum.  
  : : Sharon Turner
  : : 46, female, 92 Graves disease, Bhlephartitis upper lid retraction surgery,
  : : followed by 9 pstosis surgeries, FMS dx May 98. Rheumy and Opthal suspect MG and FMS possible secondary to MG.
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  : The test you had sounds like the repetetive nerve stimulation test.
  :  SFEMG is single fiber EMG, done with a needle inserted into a muscle with recording of electrical potentials from the muscle, you would remember if you had this one !!
  : Since myasthenia can wax and wane especially from the morning to later in the day the test can be normal in someone with MG.
  : In other words an abnormal test clinches the diagnosis but a normal one does not rule it out.
  : The antibody tests CAN be negative in someone with MG, but only in a small minority, less than 10%.
  : A biopsy is used to outrule outer causes of muscle weakness since changes in the muscle itself are usually minor or absent in MG.
  : Because of your multiple eye surgeries the relief of ptosis which is the main sign looked for during a tensilon test may not be obvious, it would however be useful if another parameter was seen to improvefor during the test, for instance the ability to hold your hands above your head.
  : A good response to the tensilon test is a predictor of a good response to Mestinon therapy.
  I have one other question I forgot to ask.  I was also given physical muscular examination of my eyes using a pencil and body strength by the doctor having me push against her or her against me.  I also was told to hold my arm extended to the side and timed.  I forgot to ask how I scored on these tests.  I am pretty sure I could hold my arm out for what seemed about a minute and a half.  I guess she could see my arm start to fall and numerous times told me to get it back up.  I Finally exhausted all strength and my arm feel in about 1 1/2 minutes.  How does this rate as far as timed strength.  The scary part was is that I used to be a fitness trainer and found myself unable to keep her from pulling my arm away from my chest.  Is their any criteria that is used or is this test just based on personal observation from the doctor on strength?  
  I also have no problems with pstosis on my right eye.  My left lid does fall slightly even after the pstosis surgeries but only when very tired.  During the eye exam she held a pencil up and had me look at it.  I felt my right eye strain more than my left then it seemed like my right eye lid fell and then opened back up and I could see more clearly with it.  My left seemed to just get more blurred.  Couldn't really feel the eye lid on my left eye change.  Is that normal to have the lid feel weaker and then open up more on the eye that doesn't pstosis?  Is it normal for the eyes to feel painful when trying to stare up for 30 seconds?  It really started hurting.
  What is the doctor looking for when they do they eye exam and have you look up at a pencil and follow it from side to side?  
  Thank you so much for your responses.  Your first response answered all of my concerns and questions about my tests.  Thank you again for this wonderful forum and the information you supply to the patients of the world.
  Sharon T.
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The test where you held your arm out is a semi-subjective test and is
scored fron 0-5 ( 0 : total paralysis, 5 : normal strength ), you
probably scored between 3 to 4 as you could hold up, your arm against
gravity but only for a relatively short period, this does suggest
significant proximal muscle weakness.
The pattern of eye movement you describe during testing by liiking up
at the pen does not fit any typical pattern and I really would not be
comfortable trying to interpret it without actually being there to see
it myself. The pain while looking up COULD have been due to fatigue,
just as any muscle feels strained if we use it beyond its capacity
( the capacity in this case being reduced ).
Following a pencil with your eyes during the exam, detects weakness of
the muscles which move the eyes around in the orbit,
(these may also be weak in myasthenia ).
If a muscle is weak the eyes do not "track " together and this difference
is obvious to the examiner, the patient usually notices this as double vision.