ORIGINAL ARTICLE / ARTICLE ORIGINAL Measurement of skin temperature after infrared laser stimulation ☆ Mesure de la température cutanée après stimulations au laser infrarouge M. Leandri a,b, * , M. Saturno b , L. Spadavecchia c , G.D. Iannetti d , G. Cruccu e , A. Truini e a Interuniversity Centre for Pain Neurophysiology, University of Genova, via Dodecaneso 35, 16146 Genova, Italy b Institute for Cancer Research, L.go R, Benzi 10, 16132 Genova, Italy c Institute of Biophysics. National Research Council, via De Marini 6, 16149 Genova, Italy d Department of Human Anatomy and Genetics, University of Oxford, South Parks road, Oxford OX1 3QX, United Kingdom e Department of Neurological Sciences, La Sapienza University, viale dell’Università 30, 00185 Roma, Italy Received 29 November 2005; accepted 17 July 2006 Available online 23 August 2006 KEYWORDS Laser; Skin temperature; Pyrometer; Pain; Heat; Perception; Laser evoked potentials Abstract Objectives. – Several types of lasers are available for eliciting laser evoked responses (LEPs). In order to understand advantages and drawbacks of each one, and to use it properly, it is important that the pattern of skin heating is known and duly considered. This study was aimed at assessing the skin temperature during and immediately after irradiation with pulses by Nd:YAP and CO 2 lasers. Materials and Methods. – The back of the non-dominant hand was irradiated in 8 subjects. Temperatures were measured by a fast analogical pyrometer (5 ms response time). Stimuli were tested on natural colour (white) and blackened skin. Results. – Nd:YAP pulses yielded temperatures that were correlated with pulse energy, but not with pulse duration; much higher temperatures were obtained irradiating blackened skin than white skin (ranges 100-194 °C vs 35-46 °C). Temperature decay was extremely slow in white skin, reaching its basal value in more than 30 s. CO 2 pulses delivered with power of 3W and 6W yielded temperatures of 69-87 °C on white skin, and 138-226 °C on blackened skin. Temperature decay was very fast (4-8 ms). Conclusions. – Differences in peak temperatures and decay times between lasers and tested conditions depend on energy and volume of heated skin. The highest temperatures are reached with lesser degree of penetration, as in the case of CO 2 laser and blackened skin. Tak- ing into account the temperature decay time of the skin, the minimum interstimulus interval Neurophysiologie Clinique 36 (2006) 207–218 ☆ This research has been carried out at the Interuniversity Centre for Pain Neurophysiology, Genova, and at the Department of Neurological Sciences, Rome. * Corresponding author. E-mail address: massimo.leandri@unige.it (M. Leandri). 0987-7053/$ - see front matter © 2006 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.neucli.2006.08.004 available at www.sciencedirect.com journal homepage: http://france.elsevier.com/direct/neucli