When patient history and physical examination are strongly suggestive, that carpal tunnel syndrome is the source of your complaints, your hand specialist is likely to refer you to a neurologist to perform nerve conduction testing and EMG. Those tests measure the actual function of the nerves and the extremity. And in the case of carpal tunnel syndrome, they'll show a very localized decrease in function of the median nerve as it travels through the carpal tunnel. The tests therefore are used to confirm the diagnosis. In addition, those same tests can tell us the severity of the nerve compression. Is this mild compression or is it more significant? Is it moderate or severe compression that may be more likely to lead to nerve damage if left untreated? So those nerve tests are very important in confirming that carpal tunnel syndrome is in fact the cause of your symptoms and in determining how it should be treated.
An electromyography (EMG) or NCV (nerve conduction velocity) - those are the two tests that are commonly used to assess for carpal tunnel syndrome. The nerve conduction velocity is simpler, it's less painful. An EMG actually involves some electrical shocks, so it tends to be more painful, but it's very helpful information. The EMG (electromyography) will show the function of the muscle and whether the muscles are functioning correctly. If they're not, that can be indicative of the nerve not functioning correctly. The nerve conduction velocity itself is a different test and that actually tests the conduction of the nerve in the region where you're concerned that it may not be flowing. It's like a telephone cable and if for some reason the telephone cable isn't conducting its signal, then you're not going to get your telephone signal. Same thing with carpal tunnel. If the nerve is being compressed right here in the palm, then the signal is not going to get out to the fingers and that's why patients present with numbness in their fingers.
Most physicians who see patients with carpal tunnel will order a very special test. We call it the Electrical Pins and Needles Test, but its real name is an EMG - an Electro Myogram with nerve conductions. It's sort of like looking at an intersection and seeing how long it takes for a car to get across the intersection. The EMG looks and it sees: how long does it take for the nerve impulses to go underneath the ligament, from the wrist and into the palm? If that time is prolonged (and it can be variably prolonged - meaning some people may have it a little long, some people may have it a lot long) - that determines a degree of carpal tunnel - mild, moderate or severe. If that same test (the EMG) also shows that there are muscle cells dying, something definitely needs to be done.
The tests that we use frequently in the office to exhibit patience for Carpal Tunnel Syndrome include inspection of the hand - just to look at the hand. Sometimes when carpal tunnel syndrome is severe enough, patients actually have atrophy in their hand. It's called Thenar Atrophy, meaning in the palm, in the thenar region (which is the thumb region) right here *Demonstrates* patients can have wasting of the muscles because these muscles are innervated by the median nerve and if the median nerve is compressed to severely enough, that can lead to atrophy these muscles. So that's a very good indicator of severe carpal tunnel syndrome - if a patient comes in with numbness and tingling in their hands and wasting of those muscles. Inspection is important. Also, we use a couple classic tests including the Tinel's test. The Tinel's test is where we actually tap on the palm right here in the region of the carpal tunnel *Demonstrates* and by tapping there (and you can try this at home) - If you tap there and your fingers begin to tingle in the thumb, index, middle, and ring finger, then that is a sign that you may have carpal tunnel syndrome. Another test that we commonly use is called the Phalen's test. What the Phalen's test is, is that we actually have the patient bend their wrist, flex the wrist and hold it for 30-60 seconds and see if the patients develop numbness and tingling in the thumb, index, middle, and ring fingers. That also is a very good diagnostic test for assessing for carpal tunnel syndrome. A third test I use to assess for carpal tunnel syndrome is what's called the compression test. What that is (and again, you can try this at home) is you just put your thumb right here, right in the palm *Demonstrates* and just hold pressure. With application of pressure, oftentimes patients with carpal tunnel syndrome will develop numbness and tingling in the thumb index, middle, and specifically the radial half of the ring finger. This half of the ring finger is innervated by the median nerve. The outer portion is actually innovated, gets sensation from the ulnar nerve, so there's a distinction. The ring finger, is helpful as a distinguisher between the two nerves. A general practitioner/primary care doctor should be able to diagnose carpal tunnel syndrome, but most likely they would end up referring you to a hand specialist.
When symptoms persist and medical attention is indicated, the purpose of that initial visit is twofold. One, it's to diagnose the condition and make sure that the symptoms are in fact the result of carpal tunnel syndrome. There are conditions that mimic those symptoms fairly closely, so your doctor is going to want to know your history, when the symptoms occur, what they feel like, what precipitates them, what makes them better. The other purpose is to outline treatment. The first stage of treatment is to confirm the diagnosis with a set of tests. Those tests are called nerve conduction studies and EMG, and they're typically performed by a neurologist. Your hand doctor may refer you to a neurologist for testing. The tests will confirm whether or not your symptoms are in fact related to carpal tunnel syndrome, and very importantly, they'll also categorize the severity of the syndrome as mild, moderate, or severe. That in turn helps guide your doctor in determining the best treatment for your condition.
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