ECG/EMG Electrode Measurement

In summary: Most EMG lead sets are not shielded. If you have problems with ambient noise, the most common solution is to twist the wires for as far as possible. Twisting improves the common mode noise rejection that is inherent in the analog front end of most biosignal instruments.In summary, using alligator clip cables for EMG signals can introduce noise, but if you use short wires and a good shield, it should work just fine.
  • #1
abhiroop_k
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I need to collect data via measuring EMG signals in the upper arm. I have standard AgCl stick-on ECG electrodes. My question is, if I can use normal alligator clip cables for collecting this signal from the electrode and feed it into an instru-amp?
Will this affect the signal strength and/or induce noise and if yes, to what extent?

P.S. I need a decently distinguishable signal, to be used later for pattern recognition.
 
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  • #2
abhiroop_k said:
I need to collect data via measuring EMG signals in the upper arm. I have standard AgCl stick-on ECG electrodes. My question is, if I can use normal alligator clip cables for collecting this signal from the electrode and feed it into an instru-amp?
Will this affect the signal strength and/or induce noise and if yes, to what extent?

P.S. I need a decently distinguishable signal, to be used later for pattern recognition.

Alligator clip cables as opposed to what? Snap-on cables?
 
  • #3
Yes, I will be using button electrodes.
 
  • #4
Abhiroop,

Such a signal with this small amplitude is very sensitive to noise, so ofcourse aligator clips will introduce sufficient amount of unwanted signal especially from power line source.

In all cases you will need for band pass filter to filter out the noise & get the usefull info from the signal, however the hardest noise to eleminate is the power line noise.

So give it a try & make sure to use a short wire as much as you can in order to reduce the noise.
 
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  • #5
Contact Resistance

Alligator clips should work just fine. The only issue is contact resistance. With any connector, the spring constant of the contact mechanism, the surface resistance of the mating metals, and the contact area are what determine contact resistance. If you use strong alligator clips, it should be just as good as any other style connector as long as it is sitting still. If you have a dynamic environment (like a stress test on a treadmill) then you hay have some other issues as the contacts move around.
 
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  • #6
ScienceGeyser isn't considering that button cables have very very good shields.

Obviously there is no issue with ohmic contact unless there is a lot of motion.

I think you need very good shielding up to and even around the clip. Even the length of the clip itself will pick up noise.
 
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  • #7
Okay, a basic doubt but, I have individual button cables that have a main and a shield lead. I need to use 3 of these electrode cables together, so do I connect all their shield leads' to a common ground?
 
  • #8
Depends on your receiver. Do a google search on "ECG amplifier circuit" and look over the images. You will see different methodoligies. Study those and decide what you want/need.
 
  • #9
Most EMG lead sets are not shielded. If you have problems with ambient noise, the most common solution is to twist the wires for as far as possible. Twisting improves the common mode noise rejection that is inherent in the analog front end of most biosignal instruments.
 
  • #10
I stand corrected. I've seen shielded assemblies, so I assumed they were all shielded
 

1. What is an ECG/EMG electrode?

An ECG/EMG electrode is a small, conductive pad that is attached to the skin to measure the electrical activity of the heart or muscles. It is used in electrocardiography (ECG) and electromyography (EMG) tests to record and analyze the electrical signals of these organs.

2. How does an ECG/EMG electrode work?

The ECG/EMG electrode works by detecting the electrical signals produced by the heart or muscles and converting them into a readable waveform. The electrode is connected to a machine, which amplifies and records the signals, allowing healthcare professionals to analyze the data and diagnose any potential abnormalities.

3. Are there different types of ECG/EMG electrodes?

Yes, there are different types of ECG/EMG electrodes, including disposable and reusable ones. Disposable electrodes are typically made of adhesive material and are used for single-use only. Reusable electrodes are made of more durable materials and can be used multiple times after proper cleaning and disinfection.

4. How are ECG/EMG electrodes placed on the body?

The placement of ECG/EMG electrodes depends on the specific test being conducted. For ECG, electrodes are typically placed on the chest, arms, and legs. For EMG, electrodes are placed on the skin over the muscle being tested. The electrodes must be placed correctly to ensure accurate readings.

5. Are there any risks associated with ECG/EMG electrode measurement?

There are minimal risks associated with ECG/EMG electrode measurement. The electrodes are non-invasive and do not cause any pain or discomfort. However, some people may experience skin irritation from the adhesive material used in disposable electrodes. Additionally, proper hygiene and disinfection techniques must be followed to avoid any risk of infection.

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