EMG Conventional Wisdom

Status
Not open for further replies.

montanancee

New member
Joined
May 21, 2020
Messages
2
Reason
Learn about ALS
Diagnosis
00/0000
Country
US
State
NY
City
NYC
I am wondering if the great folks on this board can help clarify how to read some Internet horror stories out there--such as where clean EMG did NOT = no ALS. Before asking my question though, I just want to thank the PALS and CALS who respond to nervous folks on this forum. You are truly saints.

My Q:
I understand that, as a rule, clean EMG almost always = no ALS. The conventional wisdom here seems to be that the exception to this rule is for UMN symptoms. If they are the only presenting symptoms, the EMG (will/may) come back clean. But, if LMN symptoms--such as twitching--are presenting, the EMG will not come back clean.

The problem, though, is that there are enough contrary stories on the Internet right now that simply suggest this rule isn't true--or, at least, that it is an oversimplification. Take this example:
. By his own description, this PALS's progression was: twitching -> clean EMG -> weakness -> dirty EMG/ALS diagnosis. If you look enough, you can find other stories out there (although usually not with video).

So what's the explanation? Was the first EMG administered by someone incompetent? (does this really happen?). Is the individual I linked to a liar? (seems unlikely, his videos show he is clearly a PALS, and so why lie about this?).

I'd be so deeply indebted to somehow who can explain away this riddle.

One additional Q, though, that may ultimately be nearly a good as the "clean EMG = no ALS" rule. Are PALS able to make their ALS fascics STOP? Example: If you start walking, will your leg fasciculations stop? Does stimulation (a shower, for example) make them stop? I think for many BFS folks these activities will stop them. But I have never seen a PALS describe whether they can control their fasciculations.
 

Nikki J

Moderator
Joined
Mar 22, 2012
Messages
9,702
Reason
PALS
Diagnosis
04/2014
Country
US
State
MA
City
Boston
a few thoughts on this poor guy: His emg was not where his onset was. It was left and his onset was right. It sounds like he had twitching and spasticity as he talked about this stiffness as being also another first thing. That is UMN.

but we are not here to argue cherry picked cases

my twitches which are not severe are not affected by movement.

if you have a genuine question about your own symptoms ask it but no more “ I read this I saw that” please
 

montanancee

New member
Joined
May 21, 2020
Messages
2
Reason
Learn about ALS
Diagnosis
00/0000
Country
US
State
NY
City
NYC
Thank you very much for your response. And sorry to be asking my own question so indirectly. Like the man in the video, I am having fascics but no weakness and have had a clean EMG. I know that should be comforting. But it is disturbing to me that I cannot for the life of me determine a benign (i.e., stress, caffeine) cause for my fascics. I am also fearful that--like the mean in the vid--I have relatively significant lifting strength. I wonder whether that could have masked his weakness in the early stages, and whether it is also masking my own. After all, wasn't Lou Gehrig's own onset in the middle of a season where he was still able to perform for many more months?

If I may follow-up on your EMG comments--I had also been taking it as conventional wisdom that an EMG can't really be done in the "wrong spot." That is, if only a few discrete muscles are tested, it would still pick up the problem. Even if those muscles are not yet presenting symptoms. Is that wrong?
 

Nikki J

Moderator
Joined
Mar 22, 2012
Messages
9,702
Reason
PALS
Diagnosis
04/2014
Country
US
State
MA
City
Boston
Bfs is a thing. While stress caffeine etc can be a cause or an exacerbating factor it does not have to be. twitches happens to most people and some people twitch a lot. Lifters tend to twitch too.

it is my belief that emgs should not be done on people who only twitch. They never reassure My view is expressed by one of the Oxford ALS specialists who says he won’t do one without weakness.

Lou Gehrig’s performance dropped a lot. That was his onset. Similarly Pete Frates. You don’t go from perfectly healthy to paralyzed all over. One little muscle goes and then another and so on. One or 2 little muscles are going to show up in only one of 2 specific ways - can’t make x motion or do y task. Everything else is normal. Then another deficit appears.

if your only symptom is twitching and you twitch all over I still contend you should not have an emg. Most people here say they feel weak ( which isn’t an ALS symptom ) and they have an emg in that area. ALS will show in muscles beyond where you experience it but if you are seen very early and your onset is right foot then it may not show yet in your left arm. However it will show in other areas of your leg that you think are fine. I had a very early emg ( I am FALS) my one area of mild weakness showed but so did other muscle areas around it that seemed fine. Sure enough, they were the next to go.

if one has multiple symptomatic areas it is not necessary to do every area

it is not reasonable to emg every muscle
 

KarenNWendyn

Moderator
Forum Supporter
Joined
Jul 29, 2017
Messages
3,762
Reason
PALS
Diagnosis
07/2017
Country
US
State
OR
City
Southern Oregon
I’m not going to watch the video.

For someone who presents with pure upper motor neuron loss, a skilled physician will detect abnormalities on exam. Pure upper motor neuron loss is PLS, and the EMG may theoretically be normal. Some of these people eventually develop lower motor neuron signs and are reclassified as ALS.

Anyone presenting with ALS will have at least some LMN loss and will have EMG abnormalities consistent with ALS. These will show up in symptomatic as well as in some asymptomatic areas.

Keep in mind that what is important when it comes to diagnosing ALS is the big picture: clinical weakness as determined by a physician, characteristic EMG changes in multiple muscle areas, upper motor neuron signs, evidence of disease progression, and ruling out ALS mimics.

Twitching without clinical weakness and with a normal EMG is not ALS. Period.
 

lgelb

Moderator
Forum Supporter
Joined
Nov 5, 2009
Messages
9,201
Reason
Lost a loved one
Diagnosis
00/0000
Country
US
State
WA
City
Seattle
Second that. Though fascics may be annoying, they are almost always benign, in isolation. Note that last part. As Nikki noted, the "bad" EMG in the case you cited, was after weakness had begun.

If you're looking for "rules," though little in life is 100%, it's pretty reliable that twitchers who insist their EMG was falsely normal are never diagnosed.
 
Status
Not open for further replies.
Top