Laser-evoked potentials: normative values

Objective: Laser-evoked potentials (LEPs) currently represent the most reliable and widely agreed method of investigating the Aδ-fibre pathways. Many studies dealt with the usefulness of LEPs in peripheral and central nervous system diseases. We aimed at gaining normative values for LEP data. Methods: Using a CO2 laser stimulator we recorded LEPs after face, hand, and foot stimulation in 100 normal subjects. We measured the perceptive threshold, latency and amplitude of the main vertex components, and their side-to-side differences. We also studied the correlations between LEP data and age and body height, as well as gender differences. Results: Laser perceptive threshold increased and LEP amplitude decreased from face to foot (P<0.0001). The latency of hand and foot-LEPs correlated significantly with body height (P<0.0001). The amplitude, though not the latency, correlated with age (P<0.0001). LEP data did not significantly differ between genders (P>0.1). Conclusions: This study provides normative values for the main LEP data and their absolute and side-to-side limits, highlighting the physiological differences related to, body height, age, gender and stimulation site. Significance: Our data may help to improve the clinical reliability of LEPs as a diagnostic tool.