Nerve injuries can be incapacitating, but a diagnostic procedure such as an EMG can provide crucial information about specific nerve/muscle injuries in conditions such as nerve compression, carpal tunnel syndrome and sciatica.
What is EMG?
EMG (Electromyography) is a medical diagnostic procedure used to evaluate conditions related to muscle and/or nerve dysfunction. This test is performed if someone is experiencing any of the following signs and symptoms:
- Muscle spasms
- Pain in the extremities, neck or upper and lower back region
- Muscle cramps or pain
- Weakness in the limbs
EMG is helpful to diagnose nerve root compression, peripheral neuropathies, radiculopathy, sciatica, carpal tunnel or tarsal tunnel syndrome and diseases like ALS, myasthenia gravis or muscular dystrophies.
What should you expect from EMG testing?
EMG testing involves two different parts: a nerve conduction study and a needle exam for muscle testing. Both may result in some discomfort, but are usually relatively painless without the need for medication beforehand. The nerve conduction study entails stimulating the nerves at different points with small electric shocks, artificially activating them so their function can be measured. The needle exam involves inserting very fine needles into several muscles. The needle has a microscopic electrode that picks up both the normal and abnormal electrical signals given off by a muscle. Routinely both parts of the procedure will be performed, but there are situations where only the nerve conduction or muscle testing is performed.
EMG testing usually takes anywhere from 60 to 75 minutes, depending on the condition being tested and findings of the study.
What you should know before an EMG test
The EMG test is perfectly safe. Needles are used once then disposed of. Side effects may include some muscle soreness, which rarely lasts more than an hour or two after the exam. Patients on anticoagulation or blood thinners and those with pacemakers or implanted defibrillators should inform us before performing the test, but generally this is not a contraindication. Patients with joint replacements or other artificial components in their body do not need to take antibiotics specifically for the EMG. Patients on medication should take their usual medication on the day of the test. No special preparation is necessary.