Transcription:
EMG/Nerve Conduction Pain: That Tingling Feeling

Prakash Chandran: As we go through life, it's not uncommon for us to experience tingling in different parts of our bodies, especially after something like an injury or even doing something pretty normal, like typing at a desk. So how do you get that tingling sensation checked out, so you know it's not leading to something more serious?

This is A Bone To Fix, the orthopedic podcast from the Orthopedic Associates of Central Maryland Division. Today, we're going to be talking about EMG tests and nerve conduction. And we're here today with Dr. Michael DeMarco. He's an expert in electrodiagnostic medicine and interventional spine care for Orthopedic Associates of Central Maryland Division.

My name is Prakash Chandran, and I've got a bone to fix with you. Dr. DeMarco, it is great to have you here today. You know, I mentioned the EMG test. Why don't you start by telling the audience what exactly it is.

Dr. Michael DeMarco: Thank you so much for having me. EMG actually stands for electromyography, but an EMG test actually has two parts. There is the electromyography, and then there is the nerve conduction study. And these tests when combined are tests of the peripheral nervous system function and also the function of the muscles.

Prakash Chandran: Okay. So let's talk a little bit more about these two parts of the test and what exactly they are used for. So you mentioned the first part is the electromyography and the second is the nerve conduction study. So in practical terms, when does someone get this test?

Dr. Michael DeMarco: Sure. Somebody gets the test anytime they're having pain, numbness, or tingling in any extremity, or if they're having generalized symptoms of weakness all over or numbness all over.

Prakash Chandran: Okay. That completely makes sense. But just to be clear, is this for something even as simple and straightforward like carpal tunnel? Because you experience tingling during carpal tunnel or that's one of the symptoms. So when exactly is an EMG test something that's recommended?

Dr. Michael DeMarco: Well, any numbness and tingling is abnormal. And anytime it's gone on for a period of time, people should be having it evaluated, starting with their doctor, and the doctor may refer them for an EMG test if the symptoms are not getting better with treatment or especially if they're getting worse.

Prakash Chandran: Okay. So let's talk about the test itself. So I'm experiencing either prolonged numbness or tingling or I have some pain, and then I come in to get it checked out. What exactly do I go through when I get an EMG test?

Dr. Michael DeMarco: Well, the first thing is when you get there, you're having it done in an outpatient setting and you're coming into a regular doctor's office and it starts like a regular office visit. I begin by reviewing any important records, any imaging tests you've had done, your medical history. And then we do a physical examination and look at your sensation and look at your strength, test your reflexes. And that helps us construct the test.

The test is very fluid and we can do different things during the test to help arrive at a diagnosis. And as we're doing the test, as we get different findings, we may include additional tests. The nerve conduction study is typically the first part of the test and that involves putting some electrodes on your hand or your foot, and then giving you some little electrical shocks. And this happens at several different locations in the arm or the leg.

And then the second portion of the test, the EMG or electromyography, uses a very small needle electrode, and we put it into a variety of muscles in the arm or the leg or sometimes the back and the neck. And it takes some electrical measurements from the muscle while it's at rest. And then also we'll have you do like a small contraction of the muscle and then take some measurements from there. And we use those parameters to put together where is the impairment coming from? Where is the problem originating from?

Prakash Chandran: Okay, understood. So you mentioned a couple things there. You mentioned electrodes and small needles. You know, listening to this, it sounds like it might be a little bit painful. So maybe talk a little bit about what the patient experience is and how long the test itself takes.

Dr. Michael DeMarco: Sure. The entire visit should take maybe 30 to 40 minutes, but that includes a lot of the reviewing records, taking history and physical exam, the actual electrical shock. And the small needle sticks may take closer to 20 minutes. The test does have the reputation as being uncomfortable. When you read about it online, that seems to be the one thing that people always remember. But I am here to tell you that any discomfort from the test really should be minimal. The equipment has really improved over the years, so that the smallest shocks can be delivered. And the needle electrodes have gotten so much better over the years. Typically, they are about the size of an acupuncture needle.

In the hands of a qualified electromyographer, the amount of discomfort should be minimal. And you should be telling your doctor during the test if anything really feels abnormal. The majority of the tests, we're just having a conversation through the whole thing while we are acquiring the data to arrive at those conclusions. Most people do great with the test.

Prakash Chandran: Okay. That's reassuring. Still though, I think that people might be thinking, anytime there's a needle or something that's going to break the skin, there might be some risks involved. So maybe let's talk a little bit about those.

Dr. Michael DeMarco: Sure. Aside from some mild discomfort during the test, which usually resolves, at the conclusion of the test, there is a risk of bleeding and usually that takes the form of bruising in an area. Sometimes the patient could bleed a little bit and we just have to apply some pressure to make it stop. If the patient is taking a blood-thinning or anticoagulation medication, we might avoid certain muscle groups or we might shorten the test.

It's worth noting that this test is completely safe for patients who have a defibrillator or a pacemaker in place. If a patient has lymphedema and a history of a lymph node dissection, perhaps a cancer patient, they're typically told not to have procedures in a limb. And we have to be very careful when we do it in those patients. We can do it safely for those patients, but there has to be a really strong indication to do it. We can always do some other tests to try to answer the questions of what is the diagnosis, where's the pinched nerve coming from. But we can do it safely in a patient with lymphedema.

Prakash Chandran: So we talked a little before about the times that a doctor might order an EMG. I think it was prolonged numbness or tingling. Is there anything else that might cause someone or a doctor to say, "Hey, I think you might want to get an EMG to really diagnose or assess what's going on"?

Dr. Michael DeMarco: Sure. In addition to numbness, tingling, weakness, also pain in an extremity. When people have a pinched nerve, they can have pain, they can have just an intermittent tingling. They can have some constant numbness or they can have weakness. And those can occur in any combination. They can have one or all of those things. So, if a patient has those symptoms and it's not going away, or certainly if it's getting worse, an EMG would be a great next test to perform.

Prakash Chandran: Gotcha. So let's now talk about the information that comes out of the EMG and also how that information is communicated to the patient.

Dr. Michael DeMarco: One of the things I love about the eMG test is that it looks at multiple areas at once. When we order an MRI, we have to know exactly what we want to look at. We want to look at the cervical spine or the shoulder or the elbow. And when we do an EMG or a nerve test, we're actually looking at pinched nerves in the neck or pinched nerves in the shoulder, the elbow, we get to look at a bunch of different things all at once.

If somebody has numbness or tingling in the fingers, it can actually be coming from a pinched nerve in the wrist, a pinched nerve in the elbow, a pinched nerve in the shoulder region, what is called the brachial plexus. It might be coming from a nerve root or a herniated disc in the neck. It could also be coming from the central nervous system indicating perhaps a brain problem or maybe a stroke. And the nerve test helps us answer where that is coming from.

So the first thing is it helps confirm a diagnosis. Does this patient have carpal tunnel or not? And then the second thing is it helps assess the severity of the carpal tunnel. You get a sense, is this mild? Is this moderate or is this severe? We have a variety of grading scales for different types of pinched nerves. It also gives us information about the chronicity or how long this has been going on. Is this acute or is this chronic? If there has been trauma to a nerve, if there are signs that the nerve is regenerating or reinnervating, we can also get that information too. And it helps to exclude confounders or other diagnoses. It's actually very common to have more than one problem. Just because a patient has carpal tunnel, doesn't mean they can't have a pinched nerve in their neck also. And sometimes they go together.

Also in the patient that has more generalized symptoms for example, weakness, it gives us a lot of information about is this weakness coming from a nerve problem or is it from the muscles, a muscle disease or myopathy? And a patient could also have a disease of where the nerve plugs into the muscle, what is called the neuromuscular junction. So it helps refine the differential diagnosis or what we think is wrong with the patient to help us figure out the exact cause of their symptoms.

Prakash Chandran: Yeah, that makes a lot of sense. And it's so cool that this technology exists. You know, as you're talking about, you know, pinched nerves and some of the things that the EMG uncovers, I can't help but think that maybe this might be best for people that either play sports or people that are at a desk job that potentially have carpal tunnel. Can you maybe speak to some of the demographics that, you know, this affects most the people that most likely need an EMG test in their lives?

Dr. Michael DeMarco: The pinched nerve symptoms of numbness, tingling, pain, or weakness, they can arrive through a variety of mechanisms. And one is injury and people can be injured playing sports, or people get injured doing everyday things all the time. This is the, you know, sudden acute onset of symptoms that typically comes on somewhat severe. There are other things that occur that are a little bit more degenerative or age-related. And we see that in the spine a lot, and that may come on a little bit more gradual and then they get worse over time. And then there are also some inherited conditions that seem to run in families and people are just simply destined to get. So, it really knows no boundary and it can affect almost anybody at different points in their lifetime.

Prakash Chandran: Yeah, that absolutely makes sense. So, Dr. DeMarco, just before we close here today, you know, we've talked about a lot of things here. What causes someone to get that EMG test, what it uncovers, what else should people know before getting an EMG?

Dr. Michael DeMarco: I would repeat one more time that if people have numbness, tingling, pain, or weakness in an extremity that's not getting better, they need to talk to their doctor about what comes next and maybe about getting an EMG nerve conduction test. If your doctor has referred you for a nerve conduction test, you should also ask about that doctor's qualifications. Your doctor should be board-certified in EMG and nerve conduction testing. You could also go to a EMG testing lab that is accredited by the American Association of Neuromuscular and Electrodiagnostic Medicine. And the other thing I would let people know is don't lose sleep over the test. If you read about it on the computer, they may talk about it being uncomfortable, but in general, it's very well tolerated. And it's an important step in starting to get better from your condition.

Prakash Chandran: Yeah, absolutely. Because even the mild discomfort that you might feel during the test is really nothing compared to what a lifetime of living with a pinched nerve or one of these tingling sensations that could cause something more serious down the line. So it's really important to get that assessed as soon as possible, wouldn't you say, Dr. DeMarco?

Dr. Michael DeMarco: So true. These conditions typically worsen over time, if they go untreated and it could get to a point where it's irreversible

Prakash Chandran: Well, thank you. This has been a hugely insightful conversation and I definitely learned a lot today. So I really appreciate your time.

Dr. Michael DeMarco: You're very welcome. Thanks for having me.

Prakash Chandran: Of course. That's Dr. Michael DeMarco an expert in electro-diagnostic medicine and interventional spine care for Orthopedic Associates of Central Maryland Division. For more information, you can head to mdbonedocs.com. And if you found this podcast helpful, please share it on your social channels and be sure to check out the entire podcast library for topics of interest to you. That's all for today. I'm Prakash Chandran, and that was a bone that's fixed.