A month of tiny CMAPs, my saga...

[101N]

Moved my Teca to a new practice about 2mo ago. First 5 or so EMGs yada, yada, yada. Next 15 or so tiny CMAPs, normal SNAPs & needle studies. Me:"Dang a rash of axonal motor neuropathies?!*"After about my 15th remarkably tiny CMAP study - maxing out stimulus duration & sensitivity - it dawns on me: dude this is either an epidemic or it ain't right. So I check myself - my hands go to sleep @ night so I think I've got both cubital and carpal - big brisk CMAPs. I switch out the motor cables, no change. Then I call my biomed dude, he agrees to let me check him on on my exam table, big twitch response clinically but jack for a CMAP amplitude. Then I check myself again, big response, long story short: BAD GROUND CABLE.

If you do EMGs, remember this. I got a 100 more gray hairs because of this little episode.

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[lobelsteve]

Moved my Teca to a new practice about 2mo ago. First 5 or so EMGs yada, yada, yada. Next 15 or so tiny CMAPs, normal SNAPs & needle studies. Me:"Dang a rash of axonal motor neuropathies?!*"After about my 15th remarkably tiny CMAP study - maxing out stimulus duration & sensitivity - it dawns on me: dude this is either an epidemic or it ain't right. So I check myself - my hands go to sleep @ night so I think I've got both cubital and carpal - big brisk CMAPs. I switch out the motor cables, no change. Then I call my biomed dude, he agrees to let me check him on on my exam table, big twitch response clinically but jack for a CMAP amplitude. Then I check myself again, big response, long story short: BAD GROUND CABLE.

If you do EMGs, remember this. I got a 100 more gray hairs because of this little episode.

Good catch.

The number one far and away reason for any NCV/EMG abnormality is technical error.

 

[Jitter Bug]

I had the same problem but it was a faulty disc electrode. Fortunately caught it when I checked it again with the bar electrode. Pissed me off too cause it took me a few EMG's to catch on.

 

[101N]

I started taking the disc electrodes off me mid-test and checking myself, always normal? Turns out I was grounded but the patient sitting on the plinth wasn't. Drove me nuts.

 

[SSdoc33]

i think the problem is that everybody in oregon is a weakling with puny muscles

 

[101N]

Opioid induced myocyte apoptosis.