What is the role of somatosensory evoked potentials (SEPs) in the evaluation of peripheral neuropathy?

Updated: Aug 20, 2019
  • Author: Jasvinder Chawla, MD, MBA; Chief Editor: Selim R Benbadis, MD  more...
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SEPs are rarely used to assess peripheral neuropathy since standard NCSs are the test of choice. The stimulation is applied at 2 or more sites and the responses are recorded over the scalp. In the presence of polyneuropathies and mononeuropathies, SEP waveforms recorded over the scalp may be absent or show delayed latencies with normal central conduction velocities. In this way, SEPs can be used to measure the afferent fiber conduction velocities of proximal segments. Higher stimulation currents are typically required in patients with peripheral neuropathies.

SSEP studies disclosed poorly formed and delayed cortical potentials with absent lumbar (N20) potentials, thereby suggesting the presence of proximal demyelination. SSEPs were normal in the patients with pure motor CIDP and multifocal motor neuropathy (MMN) and can thus help differentiate asymmetric forms of CIDP from MMN. These findings suggest that SSEPs may be an important complementary investigation to conventional NCSs in the diagnosis of chronic acquired demyelinating polyneuropathies (CADP).

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