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What Do These EMG And NCS Reports Indicate?

Posted on Fri, 18 May 2018

Question: I need help interpreting an EMG and NCS report.
1 Sensory nerve conduction studies of the bilateral sural nerves revealed no
responses.
2 Motor studies of the bilateral peroneal nerves revealed diminished CMAP
amplitudes throughout, but normal conduction velocities.
3 There is evidence of an axonal sensorimotor polyneuropathy affecting the
lower extremities.
Translation please.

Answered by Dr. Prof. Kunal Saha (5 hours later)

Brief Answer:
Nerve conduction to and from lower limbs seriously jeopardised

Detailed Answer:
Thanks for asking on HealthcareMagic.

I have gone carefully through the report and understand your concerns. Your symptoms seem consistent with peripheral neuropathy with both sensory as well as motor involvement (former greater than latter). I would need to ask you if you are a diabetic. Deficiency of Vitamin B12 could also give rise to such a presentation. Taking methylcobalamine (Vitamin B12) 1500 mcg supplement per day for at least a couple of weeks could possibly help in improving the situation.

Let me know if I could help further.

Regards

Above answer was peer-reviewed by : Dr. Yogesh D

Follow up: Dr. Prof. Kunal Saha (2 hours later)

No I am not diabetic and rather than a b12 deficiency, I am slightly above normal range. I've been on gabapentin for a year. 300 mg twice a day to start. I'm at 600mg 3x day with very little benefit.

Answered by Dr. Prof. Kunal Saha (1 hour later)

Brief Answer:
Thanks for the update

Detailed Answer:
In such a case you need to see a neurologist and based on careful examination and evaluation he would possibly be able to ascertain the cause.

Regards

Above answer was peer-reviewed by : Dr. Kampana

Follow up: Dr. Prof. Kunal Saha (13 hours later)

I don't mean to be rude, but I requested help interpreting an EMG and NCS report. That would indicate that I've already scene a neurologist. I simply want to know what it means in layman's terms.

Answered by Dr. Prof. Kunal Saha (8 hours later)

Brief Answer:
Explained in layman's terms

Detailed Answer:
The interpretations are already given

* Sensory nerve conduction studies of the bilateral sural nerves revealed no responses.
- The sural nerve is a sensory nerve in the calf region. The test indicates a possibility of ‎Sural Neuropathy or the sural nerve being affected.

* Motor studies of the bilateral peroneal nerves revealed diminished CMAP amplitudes throughout, but normal conduction velocities.
- The common peroneal nerve is a nerve in the lower leg that provides sensation and motor function to parts of the lower leg. The test indicates a possibility of Peroneal nerve being affected.

* There is evidence of an axonal sensorimotor polyneuropathy affecting the lower extremities.
- Simply the same thing as stated above, that both the sensory and motor component of multiple nerves of the legs is affected.

Hopefully this is what you were seeking.

Regards

Above answer was peer-reviewed by : Dr. Kampana

Follow up: Dr. Prof. Kunal Saha (10 hours later)

No responses meaning what exactly, they are dead? What is a CMAP amplitude or a conduction velocitiy. What does motor function have to do with sensation?

Answered by Dr. Prof. Kunal Saha (53 minutes later)

Brief Answer:
Grasping complex concepts is not quite easy

Detailed Answer:
No, that does not mean 'dead'. Just like, if your family members cannot find you does not mean that you are dead. Compound Muscle Action Potential (CMAP) relates to the electrical impulse concerning the nerve, muscle and nerve-muscle junction. The electrical impulse passes at variable rates based on whether it is travelling through nerve (which may or may not be insulated), muscle, or other stuff, and on whether there is obstruction involved. All these involve complex technical understanding of how the body functions. The concepts are difficult to understand even for medical professionals so please do not expect that they can be explained within the scope of such an answer.

The sensory inputs reach the brain through sensory nerves and the brain generates motor nerve impulse that come to the muscles via certain other nerves. The motor function is thus a response to the sensory stimuli. If a mosquito bites you, you would feel the pain and the brain will send signal to a certain set of muscles that would make you try to slap the mosquito.

Hope that helps.

Regards

Above answer was peer-reviewed by : Dr. Prasad