28-05-2014, 12:01 PM
Electromyography (EMG) Instrumentation
Electromyography.ppt (Size: 1.65 MB / Downloads: 100)
Types of EMG
Electrode Categories
Inserted
Fine-wire (Intra-muscular)
Needle
Surface
Fine-wire Electrodes
Advantages
Extremely sensitive
Record single muscle activity
Access to deep musculature
Little cross-talk concern
Disadvantages
Extremely sensitive
Requires medical personnel, certification
Repositioning nearly impossible
Detection area may not be representative of entire muscle
Electrode Comparison Studies
Giroux & Lamontagne - Electromyogr. Clin. Neurophysiol., 1990
Purpose: to compare EMG surface electrodes and intramuscular wire electrodes for isometric and dynamic contractions
Results
No significant difference in either isometric or dynamic conditions
However: dynamic activity was not very “dynamic”
Maximizing Quality of EMG Signal
Signal-to-noise ratio
Highest amount of information from EMG signal as possible
Minimum amount of noise contamination
As minimal distortion of EMG signal as possible
No unnecessary filtering
No distortion of signal peaks
No notch filters recommended
Ex: 60 Hz