Evoked potentials to nociceptive stimuli delivered by CO2 or Nd:YAP lasers.
OBJECTIVE
This study compares the amplitude, latency, morphology, scalp topography and intracranial generators of laser-evoked potentials (LEPs) to CO(2) 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-CO(2). 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 CO(2) 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.


CONCLUSIONS
This, together with its handy utilization due to optic fibre transmission, may favour the use of Nd:YAP lasers in clinical settings.
INSERM U879- Central integration of pain unit, Lyon F-69677, France. caroline.perchet@univ-lyon1.fr
Caroline
C
Perchet
Fabio
F
Godinho
Stéphanie
S
Mazza
Maud
M
Frot
Valéry
V
Legrain
Michel
M
Magnin
Luis
L
Garcia-Larrea
D000328:Adult; D001931:Brain Mapping; D004569:Electroencephalography; D004576:Electromyography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D054020:Lasers, Gas / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology*; D017288:Pain Threshold / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology