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What to Expect When You’re Scheduled for an EMG — and What’s the Deal with the Single Fiber EMG?
Getting an EMG soon? Not sure what it involves or what kind you’re getting? You’re not alone.
Many people with symptoms like muscle weakness, fatigue, or tingling are referred for an EMG (electromyography) test.
If your doctor suspects a neuromuscular junction disorder like Lambert-Eaton Myasthenic Syndrome (LEMS) or Myasthenia Gravis, they might also order a special type called a Single Fiber EMG (SFEMG).This thread is for sharing experiences, calming nerves, and understanding what these tests actually mean.
🧠 What’s the Difference Between a Regular EMG and a Single Fiber EMG?
Regular EMG:
Uses a small needle electrode to record the activity of your muscles at rest and when you move.
It can help detect nerve or muscle damage.
Often paired with nerve conduction studies (NCS) to see how well your nerves send signals.
Single Fiber EMG (SFEMG):
Much more sensitive and precise.
It looks at how individual muscle fibers communicate with nerves — something a regular EMG can miss.
It focuses on “jitter,” or tiny timing differences between nerve signals.
It’s particularly useful for diagnosing problems with signal transmission, like in LEMS.
⚠️ Why Is SFEMG Important for LEMS?
LEMS is a rare autoimmune condition where the nerves don’t release enough chemical signals to activate the muscles properly. This isn’t always picked up on a standard EMG.
SFEMG can detect small failures in communication between nerves and muscles before obvious muscle damage shows up.It can help differentiate LEMS from Myasthenia Gravis, which affects the muscle side of the connection instead of the nerve side.
For many patients, SFEMG is one of the key tests that helps doctors make a confident diagnosis when symptoms are confusing or unclear.
🗣️ Discussion Questions:
Did your doctor explain why they chose regular EMG or SFEMG?
What helped you stay calm or comfortable during the test?
How did the results help with your diagnosis or treatment plan?
💡 Helpful Tips:
Both tests are outpatient — no need to stay overnight
You may feel mild discomfort, especially with the needle parts, but it’s brief!
Don’t wear lotion on the day of the test
Bring a list of your medications, especially if you take blood thinners
Have questions? Have you had the test before? Thinking about it coming up?
Let’s talk about it and help each other out. 💬✨ -
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Has anyone had a single fiber EMG? We would love to hear about your experience!
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