distal latency
Time interval between nerve stimulation and onset of the compound muscle action potential in nerve conduction studies.
Full Definition
Distal latency is the time measured from the stimulus artifact to the initial negative deflection of the compound muscle action potential during nerve conduction studies. This parameter reflects conduction through the most distal segment of the motor nerve, including the terminal branches and neuromuscular junctions. Prolonged distal latencies indicate slowing of nerve conduction, commonly seen in demyelinating neuropathies, entrapment syndromes, or terminal nerve pathology. Normal values vary by nerve, temperature, and patient demographics.
Usage
Usage note: Always specify the nerve tested and include normal reference values for comparison.
In Context
- "The median distal latency was prolonged at 5.2 milliseconds, suggesting carpal tunnel syndrome." — Nerve conduction study
- "Distal latencies were normal in all tested nerves despite reduced amplitudes." — NCS interpretation