Calculate nerve conduction velocity from distance and latency measurements for neurophysiology assessment and nerve function testing
Nerve Conduction Velocity
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Clinical Interpretation
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Normal Range
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Temperature Corrected Velocity
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Nerve conduction velocity (NCV) measures how fast electrical impulses travel through peripheral nerves. It's used to diagnose nerve damage, neuropathies, and conditions like carpal tunnel syndrome or diabetic neuropathy.
Several factors influence NCV including temperature, age, nerve diameter, myelination, and the measurement technique used. Cooler temperatures slow conduction while warmer temperatures increase it.
Normal motor nerve conduction velocities typically range from 50-60 m/s for upper extremities and 40-50 m/s for lower extremities. Sensory nerves are generally faster at 50-70 m/s.
Latency can be measured to either the onset of the negative potential or to the negative peak. The onset method is more commonly used as it's less affected by temporal dispersion and provides more consistent results.
Slow NCV may indicate demyelinating conditions, peripheral neuropathy, nerve compression, or axonal damage. Values below 80% of normal suggest significant nerve dysfunction requiring further evaluation.
For every 1°C decrease in temperature, NCV decreases by approximately 2-2.5 m/s. This is why skin temperature should be maintained at 32°C or higher during testing for accurate results.
Motor NCV tests measure conduction in motor nerves that control muscles, while sensory NCV tests measure sensory nerves that carry sensation. Mixed nerves contain both motor and sensory fibers.