What to Expect During Your EMG Appointment
Your visit will begin with standard nerve conduction studies, followed by a full medical history and physical examination of your medical issue. This may be followed by more specific nerve conduction studies and/or needle EMG studies. At the end of your visit, you will be educated on your medical issue, may be directed for further investigations, and/or provided a management plan.
What exactly is a “nerve conduction study”?
Nerves conduct electric charge and this ability allows them to communicate with each other. A nerve can be thought of as a co-axial cable, with copper wire (its axons) at its centre, and insulating material surrounding it (myelin sheath). To detect this signaling in the human body, the nerve is stimulated with a probe somewhere along its length on the skin surface. Gel electrodes that are placed onto the skin, again along the length of the nerve, detect the travelling impulses that the probe delivers. How well the nerve conducts the electricity provides a measure of its health.
There are different sets of standard studies dedicated for the upper and lower limbs.
What exactly is a “needle EMG study”?
EMG refers to electromyography, which in literal terms means to graph the electrical activity of muscles. This is possible when inserting a small acupuncture-type needle into muscle that is connected to a computer. As the muscle moves, characteristic patterns emerge, which is representative of both the health of the nerves supplying it, as well as the muscle itself.
Okay, but is this painful?
Nerve conduction studies are performed at the lowest stimulus intensity required to activate the entire nerve. It is akin to a zap felt when walking over carpet and touching a doorknob.
Needle EMG, on the other hand, does not stimulate like nerve conduction studies but instead records the body’s own electrical activity. It is not overly painful but can be uncomfortable for some. To combat this, we use monopolar EMG needles, as opposed to larger bipolar concentric needles, and also offer a topical vapocoolant spray to help reduce discomfort.
Do I need to prepare for my studies?
Avoid lotions and cream to the body, as this affects how the electrodes attach
Ensure that the hands and feet are clean and free of dead skin, again to allow proper electrode attachment
Medications should be taken as normal
Please bring or wear loose fitting clothing to access the arms and legs. Shorts and a sleeveless shirt (or T-shirt) is best
Can I drive afterwards?
The electrodiagnostic assessment does not impair your ability to drive.
Is there anything else I need to do afterwards?
If a needle EMG study was performed, it is normal to feel some mild soreness afterwards. In most, this disappears after 24 hours. You may apply ice or take your usual pain medications (e.g. Tylenol, Advil), if desired.
Your referring doctor will receive a report of the initial consultation in 1-2 weeks.