Electrodiagnostic Testing (EDT) studies measure the speed and degree of electrical activity in your muscles and nerves. Injuries and diseases that affect nerves and muscles can slow or change the movement of this electrical activity. If you have pain, numbness, tingling or weakness in your hands and arms, an EDT study which measures these changes can be an important tool for your physician to make an accurate diagnosis of your condition.
There are two EDT studies which are most commonly used:
EMG studies record the level of electrical activity in the muscles. NCS measure the speed at which the electrical signal travels along the nerve.
During an EMG study, a small, thin pin is inserted into a muscle to record the level of electrical activity. A normal muscle at rest is electrically silent. You will be asked to slightly tense your muscle to record the change in electrical activity. You will able to hear this electrical signal and how the level of activity changes during the test. This process will be repeated at several muscle locations during the study.
As the pins are inserted, you may feel some minor pain and discomfort. When they are removed, you may also experience some soreness and bruising, but this will disappear within a few days. There are no long-term side effects.
Electrodes (wires) will be taped to your skin in various places along the nerve pathway. The nerve will then be stimulated with a small electrical current, and the electrodes will capture both the speed and strength of this electrical signal as it travels the nerve pathway. In healthy nerves, electrical signals can travel up to 60 meters per second (approximately130 miles per hour), but will be slower and weaker in damaged nerves.
NCS are usually less uncomfortable than the EMG study. Patients rarely experience discomfort from the NCS after testing is completed.
Our EDT services are located on the second floor of our Seattle office. On the day of the test, please do not use any lotions or creams on the areas to be tested. Also, please tell us if you are taking blood-thinning medications, have lung disease or are at increased risk of infection. Your Northwest Hand physician will go over the results of the study with you during your next scheduled appointment.
Edwin D. Vyhmeister MD, C. Hendrik Kirchhoff MD and Harold J. Kirkpatrick MD - Providing services in hand and wrist injury surgery, tennis elbow and shoulder therapy and tendinitis treatment to the areas of Everett and Seattle, Washington.
Seattle Hand Surgery
© copyright 2003 - 2008, Dr. Harold J. Kirkpatrick - Northwest Hand Specialists, Inc., P.S., all rights reserved