EMG/NCV

[Guest guest]

Howdy!

My understanding is that these are two different tests, usually

performed at the same time.

The EMG (electromyography) is where they stick you with a thin needle

in your leg/arm attached to an electrode and then ask you to flex the

foot/hand. This test measures the electrical activity in the muscle

at rest and at work. A muscle can atrophy for many reasons: in

muscular dystrophy, the muscle is faulty; in neuropathy, the nerve is

faulty, and in some cases, the nerve and muscle are fine but the

junction between them is faulty (ie, the muscles can't 'hear' what

the nerves are 'saying'). This test helps differentiate between

these causes.

The NCV (nerve conduction velocity) is where they put the electrodes

on your fingers and toes and send a mild electric impulse down the

nerve from higher up the limb. If the impulse travels slowly, the

myelin is damaged (CMT1?); if the impulse is weak but travels at the

normal speed, the axons are damaged (CMT2?). This test can also

determine if the nerve is entrapped or compressed.

My NCVs weren't too bad - some of my nerves felt nothing at all (zero

conduction - AWOL - gonzo)! My feet and hands did 'buzz' for a day

or two after, as if all the nerves had been put on hightened allert.

The EMG needle didn't hurt going in, but when I flexed, WOW! I

almost fell out of my chair.

NCVs are sometimes repeated to plot the progression of nerve damage

over time. The only reason I could think of to repeat the EMG (but

I'm no doc, and their thinking is often mysterious to us, the

unitiated) would be if the doc suspected the appearance of a new

disorder on top of the CMT. But who am I to say?

Hope this wasn't too long -

[Guest guest]

Lamar here,

Many confuse the two tests. The NCV is entirely done on the surface, while the

EMG is the one they stick you with little needles. Incidentally for me, both

were somewhat uncomfortable, but were not really painful like most describe.

They will measure the degree of nerve damage and even though they may have been

done before, repeats can measure the progression.

----- Original Message -----

From: warrenre@...

egroups

Sent: Thursday, November 16, 2000 01:47 PM

Subject: [] Re: EMG/NCV

Gretchen,

I'm not sure if it would show progression. I have no technical

knowledge about these tests. I was using the common sense logic that

if an EMG or NCV gave enough data to lead to a diagnosis in childhood,

then maybe the doctors could use it as part of the family history to

help make a diagnosis in children of that adult. It couldn't hurt to

have them on hand in any case.

All I know for sure is whenever we have seen a new neurologist, they

have asked me if I had the tests before and if I knew the results.

I knew I had the tests as a child (who could forget them...) but I

could not remember the results. Back then, I didn't know enough to

care about type.

Good question though - I wonder if EMGs/NCVs show progression

throughout the course of a disease??? (Any volunteers to retake the

test to find out?)

Ruth Warren

- In egroups, Gretchen Glick <liliwigg@s...> wrote:

> Ruth, this is news to me, are you saying one's childhood EMG/NCV

would

> stay the same in adulthood, or are you just referring to the 'type'

it

> diagnoses? It seems to me that IF CMT has progressed, the EMG/NCV

would

> be different. I wish I had my teenage one to compair last summer's

with.

> Hindsight is wonderful!

>

> ~Gretchen

eGroups Sponsor