We Have A Lot of Nerve Doing a Nerve Conduction Study
- Posted on: Feb 15 2017
At Park Avenue Endocrinology & Nutrition we’re not fond of numbness, or for that matter tingling or burning. Those are all signs that your nerves may be damaged. That damage can lead to weakness in the associated limbs and permanent loss of function, so you want to catch these trends early before they do too much damage.
To test your nerve function we use a nerve conduction study (NCS). This test measures the speed of conduction of an electrical impulse through a nerve.
How is a nerve conduction study done?
During the test, we stimulate a nerve, usually with surface electrode patches attached to your skin. These patches have two electrodes that are placed directly over the nerve to be tested. One electrode stimulates the nerve with a very mild electrical impulse; the other electrode records it. The electrical activity that follows is recorded by another electrode.
Taking those measurements, we are then able to calculate the relative health of the nerve. We calculate the nerve conduction velocity by measuring the distance between electrodes and the time it takes for electrical impulses to travel between electrodes.
How we interpret the NCS numbers
We compare the numbers from your NCS to those gauged normal for that particular nerve. The speed of nerve conduction is related to the diameter of the nerve and the degree of myelination (myelin sheathes provide insulation for the nerves). A normally functioning nerve will transmit a stronger and faster signal than a damaged nerve. You can equate this with an electric wire in your house. Those wires are insulated to protect their signals. A larger wire with better insulation will send out a more consistent, stronger signal.
For most human nerves, the range of conduction velocity is 50 to 60 meters per second. This varies between nerves and among people.
When the impulses are slower than normal, this can point to damage to the nerve from a traumatic injury or from ongoing compression. Certain diseases can also affect impulse speed.
Common disorders that we can diagnose with a NCS.
Our NCS results can lead us to diagnoses of various disorders:
- Carpal tunnel syndrome
- Peripheral neuropathy
- Ulnar neuropathy
- Guillain-Barré Syndrome
- Facioscapulohumeral muscular dystrophy
- Spinal disc herniation
- Pinched nerves
- Charcot-Marie-Tooth Disease
- Sciatic nerve problems
Posted in: Nerve Conduction