Why Might You Require an EMG Test and Nerve Conduction Tests
Are you experiencing shooting pains or tingling in your hands, wrists, legs, or feet? Feeling excessively fatigued? Or do you have a strange prickling sensation in your arms and legs that won’t go away? You may need to undergo an Electromyography (EMG) test and nerve conduction tests as further diagnostics. If this is the case, then don’t worry—while they might sound intimidating at first glance; these types of tests are completely safe methods for understanding exactly what type of condition you may be suffering from. In this post, we will cover all things related to EMG and nerve conduction testing, including how it works, why it’s important for understanding certain medical conditions, how to prepare for these procedures, the associated risks involved with them (spoiler alert: there aren’t many!) and much more!
Nerve Conduction Testing
Nerve conduction testing is very often a part of these tests, and in fact, it goes before electromyography.
Some of our nerves control muscles, and we call them motor nerves. We also have sensory nerves, which send information to the central nervous system: the spinal cord, brain, and back. For this reason, we also sometimes call them afferent nerves. In contrast, motor nerves can sometimes be called efferent nerves. The motor nerves eventually activate the muscle through a neuromuscular junction.
A nerve conduction test measures the speed of electrical signals traveling through a nerve by sending tiny electrical impulses to the nerve being tested. It can help determine if there is any damage to the nerve or if there are any underlying issues that need further investigation. The results of the nerve conduction test can be used to diagnose and treat various conditions, including carpal tunnel syndrome, peripheral neuropathy, and other forms of nerve damage.
A test for weakness
The neuromuscular junction is sometimes affected by diseases such as Myasthenia Gravis, which is an autoimmune disease. The body’s own immune system attacks the receptors for the neurotransmitter acetylcholine. Over time, it leads to weakness. That’s a little bit of a digression, but the point is that nerve conduction and EMG testing can be used to evaluate everything outside of the central nervous system—the peripheral nervous system.
It’s important to know that if you have symptoms like weakness, numbness, or imbalance, an EMG test will not necessarily tell you what is causing those symptoms. The test can only tell us if the problem is in the nerves, the muscles, or the junction between them.
The more specific information we have, the better the quality of the test or the test result, and the better information you’re going to get.
What Else Nerve Conduction Test Assesses
We could test for muscle disease, which is also called myopathy, neuromuscular junction disease, and peripheral nerve disease.
Types of Single Nerve Diseases (Mono Neuropathy):
- Carpal tunnel syndrome
- Ulnar neuropathy
Sometimes, multiple nerves are involved, but they’re kind of random. We call these cases multiple mononeuropathies or mononeuropathy multiplex. These are not seen very often; usually, they are present in immune-compromised patients.
Polyneuropathy means many nerves, but it has a different meaning than multiplex neuropathy. It is a condition in which the nerves are affected symmetrically and the longest nerves are affected first. Typically, polyneuropathy starts in the toes and then works its way up the legs in a symmetric fashion.
Sometimes this is called a stocking distribution. It may eventually affect the hands, beginning in the fingers and again being symmetric. For this, we may call it a “glove-like distribution,” where you may hear a neurologist say a stocking-glove distribution.
The most common reason someone has polyneuropathy is diabetes. Unfortunately, it’s a very common problem.
Radiculopathy is a type of nerve-related disorder that can occur in the back or neck. To confirm this diagnosis, our team uses advanced testing methods such as Nerve Conduction EMG to provide you with answers about your health condition.
Assessing the Plexus
The plexuses are web-like structures of nerves in the neck, shoulder area, and also down in the pelvis. These can be affected for different reasons, sometimes because of autoimmunity and sometimes because of an injury. Sometimes there are tumors in these areas too.
How the Test is Done
We will use a machine called the Nerve Conduction Testing Machine.
The process for conducting this type of test usually involves placing electrodes on either side of the area being tested; one electrode sends an electrical impulse while the other detects it. During the test, you will feel brief tingling sensations where each electrode is placed but these sensations should not be painful. The results from this test will then be used to diagnose any potential issues with the affected area(s).
The brain and spinal cord need to constantly detect where our bodies are in space. That happens because we have specialized, fast-conducting, large-diameter nerves sending a signal to the spinal cord and the brain. Those are the nerves that we can evaluate by nerve conduction testing.
Small Fiber Neuropathies
Now, this is important too because in some cases there are very small fiber sensory nerves (small fibers) that are damaged. They may even be damaged before the large fiber nerves are damaged. These small fibers are so small in diameter that nerve conduction testing cannot detect any abnormality in those nerves if an abnormality exists.
Small-fiber neuropathies are very common. This means that lots of people have them. They usually have burning or tingling in the feet. We see this in diabetics, and even though the nerve conduction test is not the right test to evaluate small fiber neuropathy, think of having, say, a magnifying glass and a microscope. If you have something really small, you’re going to need the microscope. But it is not too small; maybe you could see it with the magnifying glass. Nerve Conduction testing is like a magnifying glass.
The Electromyography (EMG) Part of the Test
This part of the testing will need an apparatus called a stimulating electrode. Nerve conduction testing uses electricity. Your nerves are like wires and they do conduct an electrical signal. To test the nerve, we have to apply an electrical signal to the nerve.
We also have what is called a receiving electrode. The stimulating electrode and the receiving electrode are applied to different parts of the body. It could be the arm, hand, leg, foot – any specific point along the body, depending on which nerve I want to test. A little electrical signal is then applied to the nerve.
A lot of people are afraid of nerve conduction testing. They are worried it’s going to hurt. They will ask questions like: “Is it painful?” The answer is: it is a little uncomfortable. Initially, it is so mild you can barely feel it. Then it’s kind of a tickle at some points in the test. It can definitely be more uncomfortable.
I have tested people of all ages and genders. Men, women, it doesn’t matter. Almost everyone can tolerate nerve conduction testing. I think this is because we start out very light. The brain gets used to the discomfort. And by the time there are a couple of stronger stimulations, which feel like a thud or a strong tap, it’s already over.
So it is a little uncomfortable, but no one needs sedation.
How is it with the needles?
In order to detect the electrical activity in the muscle, we have to put a needle in the muscle. We are not injecting anything. These are single-use, disposable needles, and in most cases, patients are a little worried.
Because I start off with nerve conduction testing, I would say it is probably more uncomfortable. A needle is going to be connected to a cable, and there will be no more stimulating electrode.
We’re thinking about muscle diseases in these tests. In my experience, it’s usually an inflammatory muscle disease such as polymyositis or dermatomyositis, for example. We can see muscular dystrophies and myotonic dystrophies using electromyography.
Now we are checking the muscles. We check different muscles by putting a needle in and listening to the muscle at rest. This means the person is not moving. Then I ask the person to move that muscle by flexing their legs against an applied force, for example. This activates a muscle called the tibialis anterior. Muscles have fibers, and when you put tension on the muscle, it activates more muscle fibers until there is a maximal contraction.
Muscle fibers have a relationship with individual nerve fibers and the neuromuscular junction. We can use the needle exam to evaluate muscles or diseases related to them.
Just a Note from Dr. Ken
This is probably a lot of information all at once, but I hope it was helpful to you. We do EMGs all the time here at Sharlin Health and Neurology. These diagnostics are not as bad as you thought they were going to be. We’ll have some good information. We can have a follow-up visit, go over the results, and really get a better understanding of what’s going on.
Our IDENTIFY pillar in our unique five-pillar system here at Sharlin Health and Neurology is a standard in our practice. Once we’ve very clearly identified the problem, we can then talk about a variety of solutions, including the investigation of root causes. Utilizing my team and myself to take that deep dive with you and give you a personalized approach to integrating all of those root causes into a plan that is uniquely for you and ultimately gets you the results that you really want.
We invite you to discover how our clinic helps answer your questions and concerns about these tests and our unique approach to health. To learn more, simply reserve a call with us through this discovery call link so specific solutions are tailored just for you. During this call, we can discuss your symptoms in more detail and come up with a plan tailored specifically for you.
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DISCLAIMER: The information in this email is not intended nor implied to be a substitute for professional medical advice, diagnosis or treatment. All content is for general informational purposes only and does not replace a consultation with your own doctor/health professional