Question about EMG? ALS vs CNS "Spinal Issues"

[Fleetlord]

Thanks in advance for your replies...

I am 32yrs old male.

I went to Neurologist presenting with waxing/waning weakness in both thighs, burning down both calves and shins, slight numbness and pins/needles at night. One time after waking from a nap, both legs were slightly asleep from hips down. Went away after I moved around a bit. I am having twitches in both legs in random places.

Experiencing lower back pain intermittedly. Some erectile dysfunction.

I also have a little weakness/pain/slight loss of dexterity in my right hand. Also twitches in random areas of upper body. Right hand and forearm was completely numb upon waking one night. Feeling returned shortly. No other weakness.

Doctor ordered MRI on brain,neck,thoracic. Suspected MS or other demyelinating disease.

Full physical exam. Slightly brisk reflex in both knees, other wise ok. No "bad" Babisinki response.

Had NCV and EMG Yesterday.

NCV was normal.

EMG was in back and both left and right sides of lower body.

I don't have formal results yet, but spoke with doctor during exam (she did it herself).

EMG in back showed normal.

Problems started in thighs. Both thigh muscles showed slight abnomalities or abnormalities. Right thigh seemed to be worse.

She said I had some benign twitching mixed in lower down my legs and feet.

I asked about ALS. She said NO. The thighs were showing a CNS issue. It is spinal in nature and could be a MS lesion, nerve compression, or disc disease. She said it was in my lumbar region and she immediately ordered a MRI of Lumbar. Results pending..

I asked her how she knew that, and she said basically the waveform for ALS is different from that of a CNS issue. She is really steering me towards MS, with the hope of a disc issue.

Does this sound right? I've been looking around this great forum and I've haven't seen this "waveform" comment. The EMG's are either completely negative, benign, or possible/confimed ALS.

Is there a specific waveform for ALS? I'm guessing NO, because why would diagnosis be so tough if there was a specific sign?

Also, would ALS symptoms present at onset with BOTH legs at once? My thighs both started in at the same time.

I go back Monday for NCV and EMG of upper body for the hand issue.

She seems very confident it is CNS and not motor neuron. I just don't understand how she can be so confident, and others go through tons of tests and get no answers...

I understand that you guys aren't doctors or can't give out diagnosis over the net, but I really respect your opinions and believe that may of you know more than those who are treating you..

Thanks!

 

[wright]

Hello Fleetlord

I think I would be able to help you a little more if you could somehow get your hands on the specific results of your EMG.

I can give you some of the basics about waveforms, though:

Normal waveforms of the motor unit potential (i.e. electrical activity) of a muscle are small and fast and separate from each other. In other words, they would look like quick bursts that are all separate from each other.

Abnormal waveforms (with MND) will be large and polyphasic (have many phases) and have an increase in recruitment. In other words, they would look broad and noisy.

The other thing that they can see is the shape of the fasics. Initially when EMG was done, they couldn't tell the difference between a benign fasic and a fasic due to MND. Further studies were then done and now they can tell the difference.

There are other things in the EMG called positive sharp waves and fibrillations that are indicative of ongoing denervation. They are either present or not.

Having said all of that, the presence of abnormal waveforms doesn't necessarily mean you have an MND; they can be caused by many other things. The same goes for the presence of positive sharp waves and fibrillations.

EMG's are an absolute art. Make sure your neuro is very experienced and it is best if she is part of an academic institution. I would be cautiously optimistic about your results, because she sure did sound confident after doing the EMG that you didn't have an MND. Hang tight and wait for your neuro to do further testing and keep the lines of communication open with her. Keep us posted.