Why are denervated muscles beyond standard NMES device scope?

• A. They require direct current with very long pulse durations to directly depolarize muscle fibers.
• B. They respond best to short pulse NMES aimed at innervated nerves.
• C. They can be treated safely with standard NMES devices without supervision.
• D. They do not respond to electrical stimulation.

Answer: (A)

Denervated muscles must be activated by directly exciting the muscle membrane, not the nerve. When the nerve supply is gone, short, brief pulses aimed at nerves won’t cause a contraction. Instead, you need direct current with very long pulse durations that can directly depolarize the muscle fibers themselves. Standard NMES devices deliver short-duration pulses designed to recruit motor nerves, so they can’t safely or effectively evoke contractions in denervated muscle. This is why denervated muscle stimulation falls outside the typical NMES scope and often requires specialized equipment and supervision.