We recruited 6 patients with suspected SFN including somatic and autonomic symptoms and normal large myelinated fibers function evaluated by means of electroneurography (ENG) and somatosensory evoked potentials (2 pz). We carried out leg skin biopsy and laser evoked potentials (LEPs) to verify a possible diagnostic reliability of these tests.
In all patients skin biopsy showed somatic and autonomic SFN small fiber neuropathy, 5 of them (83%) showed altered foot LEPs with absent signal of N2-P2 cortical responses.
Our data demonstrated a reasonable concordance between LEP and skin biopsy in evaluating small nerve fiber loss in SFN. However these data should be considered preliminary and a larger number of patients must be recruited before to draw any definite conclusion.