Why Doctor Picks Muscles?

[krmsck841]

i´ll try to tell you why...
first of all the doctor doesnt want to scare you, so they pick a muscle that doesnt twitch.
and... hmm... your house has many power sockets, right?
to find our if theres something wrong in your electrical circuit you dont have to check every single socket, its enough to check just one single socket to get the data and to see that theres something wrong.

oh my god... never had to use a dictionary so many times

hope you understand me

 

[hCapitalize]

In other words you are saying ignore a clean EMG if I read you right?

I can't say I find that very reassuring to us worriers.

 

[chaoslord2]

Thats not much true what Bandersnatch_F said.

1) As he said, if your muscle is twitching it isnt dead and EMG would show fascics. If it doesnt twitch during EMG, in ALS there would be fibrilations, large motor units and/or positive sharp waves. Also signs of denervation or reinervation.

2) If the muscle is dead, well, EMG wont show anything but you wont be able to use this muscle.

3) One of criterias for diagnosing ALS is positive EMG finding in asymptomatic muscles, because before twitching there can be signs I mentioned above.

Hope this helps

 

[BandersnatchF]

No, I'm not a medical doctor, but I've had plenty of experience with neurological issues because I have two brothers with MS (both under treatment for it). I'm a scientist (in another field), so I find it pretty easy to understand EMGs and how they work.

A clean EMG in a symptomatic limb makes it very unlikely that you have ALS. By the time the muscle twitches, there are other, much smaller electrical signals (fibrillations and sharp waves) that an EMG will pick up. You can't detect these signals, but the EMG can.

However, this only applies to a symptomatic limb. At the onset of ALS and other NMDs, most of your neurons are still unaffected—only a few have died. If the ones feeding your leg are still healthy, your leg won't twitch and an EMG on your leg will show no signs of ALS. If, at the same time, your arm is twitching, an EMG on your arm would show signs suggestive of nerve damage. If you're twitching all over, it doesn't matter where the EMG is done. If you're twitching in just a few places (both calves and an arm), the neuro should do the EMG in those places for it to be of any value. Any decent neuro will, of course, do this.

As Kit mentioned, the difference between peripheral neuropathies (which are pretty common) and NMDs are that neuropathies tend to affect both motor and sensory neurons, which is why the NCV is used. Also, the NCV can detect physical damage to neurons, which typically shows up as slowed response time in the nerves or a diminished ability to carry signals.

The bottom line is that a clean EMG (including one with only fascics but nothing else) in a symptomatic limb is a strong indication that you don't have ALS.

 

[JosiahManning]

This board is about giving hope to folks. Hope, and the human mind--where hope resides, have the power to heal. For those that want to debunk "myths", be it about EMGs or the odds of dying of ALS (or the existence of Santa Claus with a 4 year old), might I suggest that there are better forums for you to apply your scientific rigor.

You have left a large number of folks confused and unnecessarily scared--whether your "stats" are right or wrong. This is my last posting on this topic. Feel free to take the last word FBandersnatch (like you could actually resist . . .).

J.