EMG Needle Electrodes

CNSAC MedShop provides a wide spectrum of EMG needles for electromyography. All our EMG needle electrodes are high quality, offer optimal signal quality and noise reduction and ensure a smooth penetration to help reduce patient discomfort.

What is the difference between Monopolar and Concentric EMG Needles? Scroll down to read more.

Monopolar and concentric needles have different characteristics. The clinical use of each type depends  on many different factors like the physicians preferences and the type of study.

Monopolar EMG Needles

Most monopolar needles range from 26 to 31 gauge. They are made of stainless steel with an insulating material layer. They normally have a conical shape which enables you to  record from multiple directions. The recording area of monopolar needles is 3 x  larger than with the equivalent concentric needle. In addition, monopolar EMG needles have a lower impedance. As a result they can record more electrical activity in comparison to conectric needles.

To perform electromyography (EMG) using monopolar needles, the needles act as an active electrode. A reference/surface electrode should be placed close to the active electrode, whereas a ground electrode should be placed away from both the active and reference electrodes.

Concentric EMG Needles

Concentric needles consist of both an active electrode (a silver core) and a reference electrode (a stainless steel cannula) in the same unit. The tip shape is  elliptical with an angle of around 15 degrees.

With a focus on recording repeat-ability, the concentric needles show a higher reproducibility than monopolar needles and the signals are more stable. The process is also easier - as no reference electrode is needed.

References

Daube JR1, Rubin DI (2009) Needle electromyography. Muscle Nerve. 39244-39270
Sonoo M (2002) New attempts to quantify concentric needle electromyography. Muscle Nerve Suppl. 11: 98-102
Wiechers DO, Blood JR, Stow RW (1979) EMG needle electrodes: electrical impedance. Arch Phys Med Rehabil. 1979 60: 364-369

 

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