EMG and NERVE CONDUCTION TESTS
The NCV: Nerve Condition Velocity Test
An NCV test evaluates the health of the peripheral nerve. Stimulating
electrodes are placed at different points on a limb and an electrical
pulse is generated. Recording electrodes placed on a muscle elicits a
waveform produced by the nerve when the pulse is generated. The
information received can help to identify a problem area.
What is it?
- it evaluates the health of peripheral nerves (motor and/or sensory)
- it measures the speed of an impulse traveling along a motor nerve
(one that goes to a muscle) or a sensory nerve (one that detects
sensations)
How long does it take?
Why is an NCV performed?
- if you are experiencing muscle weakness, numbness, nerve injury,
mechanical nerve pressure, or nerve disorders due to a variety of
diseases
Does it hurt?
- during the test, your muscles may twitch or tingle and there may be
some discomfort
- the NCV is NOT a shock treatment or a therapy of any kind
Where is it conducted
What should you do to prepare for the test?
- eat normal meals
- continue to take prescribed medications, unless your doctor gives
you other instructions
How is it performed?
- you will lie on an examination table
- "stimulating" and "recording" electrodes will be placed on different
areas of your limbs
- a "pulse" from the stimulating electrodes will be measured by the
recording electrode, which elicits a waveform
Following the test
- the electrodes will be removed
- you may return to your hospital room or go home, unless given other
instructions by your doctor
- you will learn the test results from the doctor either on the day of
the visit, or from a copy of the letter sent to your personal physician
The EMG: Electromyography Test
An EMG evaluates the health of your muscles by measuring electrical
activity. A thin, small electrode (needle) is inserted into one of your
muscles, which is evaluated at rest and at various degrees of contraction.
What is it?
- evaluates the health of your muscles by measuring electrical
activity
- a small thin electrode (needle) is inserted into one of your
muscles, which is then evaluated at rest and at various degrees of
contraction
How long does it take?
- about 30 minutes to one hour
Why is an EMG performed?
- if you are experiencing weakness in your arms, legs, hands, or face
- can determine whether weakness is due to muscle disease, nerve
disease or disease of the junction between nerve and muscle
Does it hurt?
- you may experience some pain when the needle is inserted into each
of the muscles being tested. Some discomforts should be expected during
this test.
- the EMG is not acupuncture or a skin treatment of any kind. Nothing
is injected into or under your skin.
Where is it conducted?
What should you do to prepare for the test?
- eat normal meals
- continue taking prescribed medications unless your doctor gives
other instructions
- tell your doctor if you are taking a "blood thinner" such as
coumadin, heparin, or aspirin, or if you bruise easily
How is the EMG performed?
- before the EMG begins, a doctor will give you a brief neurological
exam to check your nervous system and muscles
- you will then lie on an examination table
- the doctor will insert a needle electrode into the muscle
- your muscle will then be evaluated at rest. During this phase, the
needle is moved several times so that various sections of the muscle can
be tested. This may cause some discomfort.
- you will be asked to flex your muscles slightly, and then as hard as
you can, and additional measurements will be taken
- the number of muscles to be tested depends in the problem you have
and what is found during the test
After the test
- you may return to your hospital room or go home, unless given other
instructions from the doctor
- there might be a slight tenderness in the muscles that were tested,
but this should go away in a few hours. Your muscles may also ache for 1
or 3 days
- you will learn the test results either from the doctor before you
leave, or from a copy of the letter sent to your personal physician
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