Decreased motor nerve conduction velocity

What it means

A type of decreased nerve conduction velocity that affects the motor neuron.

Newborn infants have values that are approximately half that of adults, and adult values are normally reached by age 3 or 4. Motor nerve conduction is evaluated by recording the compound muscle action potential (CMAP) associated with a mechanical contraction of a given muscle in response to electrical stimulation of the motor nerve fibers supplying that muscle. The CMAP is the sum of all the action potentials occurring individually in the contracting muscle fibers.

Rare diseases that can present with this17

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Also called: Decreased motor NCV · Decreased motor nerve conduction velocities · Reduced motor nerve conduction velocity