What is the nomenclature of somatosensory evoked potentials (SEPs) components?

Updated: Feb 26, 2019
  • Author: Sombat Muengtaweepongsa, MD, MSc; Chief Editor: Selim R Benbadis, MD  more...
  • Print


SEP components typically are named by their polarity and typical peak latency in the normal population. For example, N20 is a negativity that typically peaks at 20 milliseconds after the stimulus. The normal latency value for a component in a particular individual may be different from that implied by the component's name, because the lengths of the peripheral nerve and spinal conduction pathways, which vary with the patient's stature, influence the latencies of the SEP components. [4]

The nomenclature of an evoked-potential component is inconsistent in the literature because the recording montage is not specified with the peak latency and polarity. For example, a CPi-EPc linkage following median nerve stimulation records a P14, while an EPc-CPi linkage records an N14. Also, the primary cortical SEP to median nerve stimulation, most often called N20, is sometimes referred to as N19 because of its mean latency in the author's control population.

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!