Contact Heat Evoked Potential in normal subjects: is there any disparity among different Centers? (P5.140)

Objective: This study aims to establish normal CHEPs data from a specific population, comparing to other normative data already published. Background: Contact heat evoked potentials (CHEPs) are a non-invasive tool to study small fibers involvement. By applying a heat stimulus (51 °C) over the skin, evoked late cerebral potentials are created. Thus, amplitudes and latencies are obtained, being utilized to detect small fibers alterations in neuropathic pain patients. However, few centers have been described normative data and its different results obtained when comparing to other centers. Design/Methods: Normal subjects underwent CHEPs stimuli, being applied on face, cervical (C7), distal arm, lumbar (L1) and distal legs, and recorded in Cz and Pz, according to standard technique. All the patients were divided by age and gender. We measured the influences of verbal rating scale (VRS) as well as age on N2-P2 amplitudes. Similarly, we tested the influence of height and age on N2 and P2 latencies. In addition, 5th percentile for amplitudes and 95th percentile for latencies were calculated. Results: 36 patients were enrolled in this study. Only 1 out of 36 patient was excluded for not having recordable CHEPs in any location. Differently from some studies, no impact of VRS and height was found on the variables N2-P2 amplitudes and N2 and P2 latencies, respectively. However, age was significantly correlated to N2-P2 amplitudes, N2 and P2 latencies over all the locations stimulated. Yet normative data was similar to the published for other centers. Conclusions: We provided normative data for CHEPS usage in a Brazilian population for the very first time. Overall, the CHEPS data found were not so different as published for some other centers. Some of the few differences found may represent the characteristic of stimulus applied or even some particularities from the own population studied. Disclosure: Dr. Herculano has nothing to disclose. Dr. Pupe has nothing to disclose. Dr. Passos has nothing to disclose. Dr. Davidovich has nothing to disclose. Dr. Pessoa has nothing to disclose. Dr. Nascimento has nothing to disclose.