Home HealthTopics Health Centers Reference Library Research
Join us on Facebook Join us on Facebook Share on Facebook

Myasthenia Gravis

EMG testing/reliability



First, I thank-you for all the helpful information you have provided over the past months. My question now is: Why is it that after three prior EMG`s (over the past 12 months), only now did the test reveal MG? Friends ask me this and I am unable to provide an educated response. Thank-you.


Your situation is not unique and there are several reasons for what has occurred. The results of the test are dependent on the severity of the MG, medications taken prior to the EMG, and test conditions. An EMG is a human test and therefore is dependent on the test conditions and the expertise of the operator. As you may know, the EMG is not an absolute test at most 90% of patients with MG will have an abnormal test. The percentage is even lower among patients first developing the disease.

For more information:

Go to the Myasthenia Gravis health topic, where you can:

Response by:

Henry J Kaminski, MD Henry J Kaminski, MD
Formerly, Professor of Neurology
School of Medicine
Case Western Reserve University