A motor unit is defined as one motor neuron and all of the muscle fibers it innervates. When a motor unit
fires, the impulse (called an action potential) is carried down the motor neuron to the muscle. The area
where the nerve contacts the muscle is called the neuromuscular junction, or the motor end plate. After
the action potential is transmitted across the neuromuscular junction, an action potential is elicited in all
of the innervated muscle fibres of that particular motor unit. The sum of all this electrical activity is
known as a Motor Unit Action Potential (MUAP). This electrophysiologic activity from multiple motor units
is the signal typically evaluated during an EMG. The composition of the motor unit, the number of
muscle fibres per motor unit, the metabolic type of muscle fibres and many other factors affect the
shape of the motor unit potentials in the myogram.
MUAP analysis is performed by means of intramuscular (needle) EMG.
Acquisition Parameters
Channel numbers: 1
High Pass filter: 5 Hz
Low Pass filter: 5000 Hz
Base Time: 200 msec
Signal Max: Auto
Gain/Div: 150 µV/div
Manual MUAP working modality
This function allows user to manually trigger all the motor unit to analyze. During needle EMG
examination, click on MUAP button or start MUAP directly by means of the dedicated protocol.
Then select the side and the muscle to record, finally click on Manual MUP analysis key.
Analysis Time frame allow the user to select the length of trace epoch to analyze.