What are the considerations while doing nerve conduction studies due the size of nerve fibers?
• The standard Nerve conduction studies reflect only the largest and fastest fibers. The small fibers are not recorded. So small fiber neuropathy cannot be diagnosed with nerve conduction studies. • Sensory nerve conduction studies study the A-Beta fibers which carry cutaneous sensation. The size and conduction velocity of these fibers are very similar to the alpha and gamma motor neuron efferents to the muscle fibers. So while doing the sensory nerve conduction study exercise caution about recording the motor fibers. • Ia afferents from the muscle spindle are the fastest fbers and are not recorded during routing motor or sensory conduction studies. They are recorded only during the mixed nerve conduction studies.
