Evoked potentials to nociceptive stimuli delivered by CO2 or Nd:YAP lasers

• Published in: Clinical neurophysiology 2008-11, Vol.119 (11), p.2615-2622
• Main Authors: Perchet, Caroline, Godinho, Fabio, Mazza, Stéphanie, Frot, Maud, Legrain, Valéry, Magnin, Michel, Garcia-Larrea, Luis
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Brain Mapping; Cognitive science; Electrodiagnosis. Electric activity recording; Electroencephalography; Electromyography; Evoked Potentials, Somatosensory - physiology; Female; Functional Laterality; Fundamental and applied biological sciences. Psychology; Humans; Investigative techniques, diagnostic techniques (general aspects); Lasers, Gas - adverse effects; Male; Medical sciences; Middle Aged; Nervous system; Neurology; Neuroscience; Pain - etiology; Pain Threshold - physiology; Reaction Time - physiology; Somesthesis and somesthetic pathways (proprioception, exteroception, nociception); interoception; electrolocation. Sensory receptors; Vertebrates: nervous system and sense organs
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2008.06.021

Abstract Objective This study compares the amplitude, latency, morphology, scalp topography and intracranial generators of laser-evoked potentials (LEPs) to CO2 and Nd:YAP laser stimuli. Methods LEPs were assessed in 11 healthy subjects (6 men, mean age 39 ± 10 years) using a 32-channel acquisition system. Laser stimuli were delivered on the dorsum of both hands (intensity slightly above pain threshold), and permitted to obtain lateralised (N1) and vertex components (N2-P2) with similar scalp distribution for both types of lasers. Results The N1-YAP had similar latencies but significantly higher amplitudes relative to N1-CO2 . The N2-P2 complex showed earlier latencies, higher amplitudes (N2) and more synchronised responses when using Nd:YAP stimulation. The distribution of intracranial generators assessed with source localization analyses (sLORETA) was similar for Nd:YAP and CO2 lasers. The insular, opercular, and primary sensorimotor cortices were active during the N1 time-window, whereas the anterior midcingulate, supplementary motor areas and mid-anterior insulae were active concomitant to the N2-P2 complex. Conclusions Earlier latencies and larger amplitudes recorded when using Nd:YAP pulses suggest a more synchronized nociceptive afferent volley with this type of laser. Significance This, together with its handy utilization due to optic fibre transmission, may favour the use of Nd:YAP lasers in clinical settings.