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Why would this be inflicted upon you in
first place? Usually it's because your own doctor thinks you might have a nerve or muscle condition and wants to narrow down
possibilities, seek confirmation, or eliminate a particular diagnosis.
Electromyography is a term meaning "electrical muscle recording." Because muscle is an electrical tissue,
needle electrode in
muscle, when connected to an amplifier and an oscilloscope screen, can show
muscle's electrical activity as a series of voltage-fluctuations. Moreover,
signal is also fed through a speaker, so you and
electromyographer can listen to what
muscle has to say. Each muscle is analyzed while you tense it, and again while you relax it.
Normal muscles display typical patterns to
eye and ear through
oscilloscope and speaker. Abnormal muscles show altered patterns. Sometimes
abnormality is more evident on
oscilloscope, and sometimes more evident on
speaker. Muscles that are themselves sick (myopathy) show one pattern, while muscles that are connected to sick nerves (neuropathy) or spinal roots (radiculopathy) can show yet another pattern.
Electromyography is often paired with nerve conduction studies performed at
same testing session by
same doctor and with
same equipment. Each test—EMG and nerve conduction studies—has its own story to tell, as well as its own strengths and weaknesses in its ability to show signs of disease. The results of
electromyography and nerve conduction studies are considered together to come up with a more complete, combined test-outcome and report.
The time required for testing can depend on
nature of
problem. Also,
electromyographer might add or subtract additional testing depending on how
initial components turn out. Overall, a typical session might last between 45 and 90 minutes. That doesn't mean that
patient is subjected to unpleasantries during that whole period of time. Actually, much of
time is devoted to getting all
little pieces and parts of equipment organized and in place for each "mini-test" comprising
overall testing session.
So when your doctor refers you for electromyography, don't listen to your brother-in-law. What does he know anyway? (Wait a minute, I'm somebody's brother-in-law, too! But you get
idea.) As an adventure, EMG is less than it's cracked up to be. As a diagnostic test, it can be very useful.
(C) 2005 by Gary Cordingley
