To perform intramuscular EMG, a needle electrode is inserted through the skin into the muscle tissue. A
trained professional (most often a physiatrist, neurologist, physical therapist, or chiropractor) observes
the electrical activity while inserting the electrode. The insertional activity provides valuable information
about the state of the muscle and its innervating nerve. The signal collected by the amplifier is then
displayed into the screen and, in the same time, it is sent to the computer speakers.
Normal muscles at rest make certain, normal electrical sounds when the needle is inserted into them.
Then the electrical activity when the muscle is at rest is studied. In normal subjects, we should not find
electrical activity in this condition; abnormal spontaneous activity might indicate some nerve and/or
muscle damage.
Then the patient is asked to contract the muscle smoothly (voluntary activity). The shape, size and
frequency of the resulting motor unit potentials is judged. The step between electric silence and
maximum electrical activity should result gradual in normal subjects.
Patient may further be asked to perform a maximum effort in order to study the interference pattern
generated by the overlapping of the various motor unit action potentials.
Then the electrode is retracted a few millimeters, and again the activity is analyzed until at least 10-20
units have been collected.
Each electrode track gives only a very local picture of the activity of the whole muscle. Because skeletal
muscles differ in the inner structure, the electrode has to be placed at various locations to obtain an
accurate study.
As normal practice during the recording, the doctor add comments to the report describing the
characteristic of the collected EMG signal (e.g. fibrillation and fasciculation level).
Spontak Aktivite Kayıt Parametreleri
Channel numbers: 1-2
Low filter: 16 Hz
High filter: 5000 Hz
Base Time: 100 msec -10 sec
Signal Max: 3.2 mV
Gain/Div: 50-100 µV/div
Volunter Aktivite Kayıt Parametreleri
Channel numbers: 1-2
High Pass filter: 16 Hz
Low Pass filter: 5000 Hz
Base Time: 100 msec – 10 sec
Signal Max: 25.6mV
Gain/Div: 1-5 mV/div
Maksimal-Kası Kayıt Parametreleri
Channel numbers: 1-2
High Pass filter: 16 Hz
Low Pass filter: 5000 Hz
Base Time: 100 msec – 10 sec
Signal Max: 25.6mV
Gain/Div: 1-5 mV/div