Electromyography (EMG) is the recording (graphy) of the electrical activity (electro) of your muscles (myo). This is typically an extension of the nerve conduction study, whereby a very small needle is inserted into the muscle and we observe the pattern of activity to determine if there is any injury to the nerves connected to the muscle.
In some cases, we can detect disease in the muscle itself (myopathy). Injury to nerves can manifest as abnormal, spontaneous activity in muscles and an EMG can give information about nerves being pinched, such as those in the neck or lower back (usually slipped discs).
It can also provide information about injury or diseases of the nerves themselves, such as the extent of damage to the median nerve at the wrist (carpal tunnel syndrome). This information can be very helpful in understanding where, and to what degree, there is damage to nerves and guide your referring physician’s decisions on further testing and treatment.
What should I do to prepare for an NCS/EMG?
We ask that you not use hand lotion or creams on the day of your test. Loose-fitting clothing that can be rolled up to above the elbows and knees is very helpful. Bracelets, rings, and watches will usually be removed for tests on the hands, and socks or tights removed for investigation on the feet.
Are there any possible side-effects or complications?
While it may sound alarming to have an electrical impulse applied to your skin, the amount of electricity that passes through you is very small. Most people tolerate the test very well and have no side-effects or complications after the test.