Info about EMG
Does EMG hurt? I have been told it is extremely painful.
Patients often come to their test fearful of what may happen to them. We do our very best to calm fears by providing detailed description of everything we are planning to do beforehand, so that the knowledge empowers the individual. Many patients admit that it “was not nearly as bad as they expected”. However, we know that everyone has a different tolerance for discomfort, and we are sensitive to patients comfort. You are fully in control, and if you feel you have had enough at any time, please tell the physician, and the test will be stopped immediately. While we do our best to minimize the amount of discomfort to patients, we also recognize that in order to make a correct diagnosis, sometimes a minimum number of tests must be done to be sure about the correct answer. If we do not have enough information to give to your doctor, we will communicate this clearly in the report.
Are there certain medications that I cannot be on when having this test?
You should not stop any of your medications without consulting with your doctor. The only medicines which may need to be stopped prior to the test might be warfarin blood thinning medication, however this must be done only in consultation with your doctor. Certain medications such as Mestinon for myasthenia may in certain circumstances be held prior to the test, but again this should only be done in consultation with your doctor.
Is it a problem if I have metalwear or a pacemaker?
In general, metalwear (e.g. joint replacement) poses no problems for this test. Also, patients with pacemakers may safely undergo this test. If you have an implanted automated cardioverter-defbrillator device (AICD), you may need to have this temporarily deactivated, and in general we do not provide this service outside the hospital and under direct supervision by a cardiologist. You should tell the doctor prior to the test if you have such a device.
What is the difference between nerve conduction studies and EMG?
They are different tests, but are usually done together. Nerve conduction studies allow the function of the peripheral nerves to be assessed by stimulating the nerve with direct current and then measuring over the nerve or muscle the electrical response. The speed of conduction and the size of the electrical response provide an assessment of the integrity of the nerve. Many nerve problems (eg, carpal tunnel syndrome) cause focal pinching of the nerve and slowing of conduction which can easily be measured with this test. The sensation of nerve stimulation is similar to a static electricity shock, and although uncomfortable, does not in itself cause any nerve damage.
EMG (electromyography) does not involve any electrical stimulation. A small wire electrode (like an acupuncture needle) is placed into the muscle and the electrical activity in the muscle is monitored for a few seconds. Anywhere from one to ten muscles may be sampled, depending on what we are testing for. In many cases, there is no discomfort at all, or only minimal slight discomfort at the needle site, and there is no damage to the muscle from doing this test.
How long will the test take? Can I drive or work straight away?
The test will take between 20 minutes if straightforward, to an hour if more complicated. Where possible we try to use the information from your referring doctor to tell us how much time to allot to each study, but of course sometimes the study may be more detailed than initially thought. You will be able to drive to and from this test, and do not need to take any additional time off work.