Pain-related nociceptive evoked potential and skin wrinkle test in small fiber neuropathy

A 58-year-old woman with clinically probable small fiber neuropathy (SFN), with normal electroneuromyography, was evaluated with pain-related nociceptive evoked potential (PREP) with a concentric planar electrode stimulation on the dorsum of the hands and feet and skin wrinkle test (SWT). The PREP showed N1 latency delay, compatible with the change in SWT induced by water, which indicated a Grade 0 pattern, as can be seen in sympathetic autonomic small fiber dysfunction. New electrophysiological tools, combined with SWT and specific neurological examination, contribute to the diagnosis of SFN.