This overlap is not normally a major issue, as many times there is both large and small fiber damage. John Hopkins School of Medicine website lists the symptoms of small fiber neuropathy as:Ĭonfusingly enough there is overlap between the symptoms caused by small fiber damage and large fiber damage. If there are large diameter nerve fibers, there must be small diameter nerve fibers right?Īnd problems with these nerves are not picked up by the EMG/NCV tests. Large fiber damage will mostly give symptoms of numbness, tingling, weakness, and loss of coordination (the body loses track of its feet/parts). In general, these types of nerves are called large diameter nerve fibers. Its purpose is to speed up nerve impulses for things that have to go FAST like all of the quick corrections we do to stand and walk upright, feel touch, vibration, etc. Think of myelin as the insulation around an electrical wire. You see, these two tests are only good for nerves that have a myelin sheath. These tests can help determine if it’s one or the other or both.īut what if you have a “negative” EMG/NCV?ĭoes that mean that you don’t have neuropathy? Not necessarily. Off of the top of my head I would guess that about 20% of the patients that I see in my practice have issues at the ends of their nerves (from peripheral neuropathy) as well as some problems at the beginning of their nerves (like disc degeneration or lumbar stenosis or something).īut many times it is one or the other or the symptoms are from mostly one or the other.

Can anyone think of a reason why you couldn’t have a nerve issue up top (like sciatica or a “pinched” nerve) as well as some damage at the ends of the nerves? Nope! You are entitled to have many things wrong with you at once. Keep in mind that there is no limit on what you can have wrong with you. You are entitled, however, to have multiple things wrong with you A good way to think about how they work is that they shoot electrical impulses into one end of your nerves and measure how fast and how “big” the impulses come out of the other end.īased on this testing, the clinician might be able to get a sense of whether the damage is to the ENDS of the nerves (like the hands/feet) or if the problem is at the BEGINNING of the nerves (like a herniated disc by the spine). (You can skip to the chase here – you CAN have peripheral neuropathy with a normal EMG/NCV)Ī very common method of testing for peripheral nerve damage are electromyelegrams (EMG) and nerve conduction velocity (NCV) tests, they are called electrodiagnostic tests as well. Negative EMG/NCV so I don’t have neuropathy? Not so fast!!

How painful are emg tests