Laryngeal Electromyography (LEMG)
A
test that measures the electrical discharges from voice box muscles
during activities such as speaking, breathing, and swallowing
Paresis
Partial paralysis; partial loss of nerve input to a muscle, resulting in muscle weakness
Paralysis
Complete loss of nerve input to a muscle, resulting in complete loss of muscle function
Motor Unit
The
functional unit made up of all muscle fibers that receive nerve inputs
from a single nerve cell; a muscle is made of many motor units
Laryngeal
Electromyography (LEMG) is a medical procedure that records the
electrical activity produced by voice box muscles in action. LEMG gives specific information as to whether the nerve input into a
particular muscle is normal or abnormal. During LEMG, electrical
activity is recorded, amplified, and displayed on a screen and/or
played on a loudspeaker to allow visual and sound analysis.
Nerve
input is necessary for muscles to move. Nerve input is an electrical
impulse that triggers electrical activity in the muscle fibers
connected to the nerve. Electrical activity then spreads throughout the
muscle and causes chemical changes, which lead to muscle contraction or
movement. Muscle movement is associated with electrical activity;
muscle contraction itself does not produce electrical activity.
LEMG can give detailed information that helps in the investigation of voice disorders caused by partial loss (paresis) or complete loss (paralysis) of nerve input.
LEMG
is performed in the clinic with the help of a laryngologist, a
neurologist, and/or technician – all members of the voice care team.
There is no electric shock. Through the use of special fine needles (electrodes), LEMG measures electrical activity during muscle activity in certain voice box muscles.
