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Defective E2 electrode lead gives low-amplitude compound muscle action potential
Sanjeev D Nandedkar1,2, Paul E Barkhaus2
1Natus Medical, Inc, Middleton, Wisconsin.
Muscle & Nerve
|January 6, 2023
Summary
A defective E2 electrode lead significantly reduces compound muscle action potential (CMAP) amplitude, by over 65%. This highlights the importance of checking for technical artifacts, like faulty electrode leads, before diagnosing neuromuscular pathology.
Area of Science:
- Neuromuscular physiology
- Electrophysiology
- Nerve conduction studies
Background:
- Low-amplitude compound muscle action potentials (CMAPs) can indicate neuromuscular disorders or technical artifacts.
- Defective electrodes or leads can cause inaccurate CMAP recordings.
Purpose of the Study:
- To investigate the impact of a defective E2 electrode lead on CMAP amplitude.
- To differentiate between pathological CMAP reduction and technical artifact.
Main Methods:
- Standard nerve conduction methodology was used to record CMAPs.
- Simulated defective electrode leads by disconnecting E1 or E2 leads from the amplifier.
- Experiments were conducted on four nerves in a healthy subject.
Main Results:
- Disconnecting the E1 lead reduced CMAP amplitude as expected.
- Disconnecting the E2 lead, while E1 was connected, caused a surprising amplitude reduction exceeding 65%.
Conclusions:
- Both E1 and E2 electrodes are crucial for accurate CMAP recording.
- A defective E2 lead can lead to a significantly attenuated CMAP due to amplifier properties.
- Technical artifact, particularly faulty electrode leads, must be ruled out before considering neuromuscular pathology in low-amplitude CMAP findings.
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