Reply To: Second EMG, need advice

July 22, 2012 at 12:47 am


NCV instruments measure very small signals and so are susceptible to environmental noise. To do an NCV study well, the room where it is done needs to have electromagnetic shielding, to block the environmental noise. My guess is that your doctor’s office is not shielded. Even if it were, there are still several reasons why an NCV instrument might give bad data: faulty leads, a failed capacitor, a noisy power supply, and many others. As somebody who uses scientific instruments, I can tell you that they fail. It is good that your doctor recognized a possible problem and rescheduled you with a different lab.

Sometimes the correlation of clinical response and NCV results is not very good. Many people have GBS and CIDP with severe symptoms and nearly normal NCV. And sometimes, it is the other way around. As Goodney points out, the test is subject to interpretation and technique. The point is that the test is not the end-all, be-all in diagnosis, just one part of it

So let’s pretend that your nerves are in fact worse. You feel better than you have, in spite of that. Your doctor wants a more aggressive treatment schedule. Most likely, that would mean more IVIg more often. You said that in the last week between treatment, you start to decline. So if you have a more aggressive treatment, you might avoid the decline entirely. Sounds like a win to me, unless the treatment itself is burdensome.

How did the test go Friday?