title: Effects of aging on laser evoked potentials.
abstract: BACKGROUND
  Aging has been reported to reduce the amplitude of laser evoked potentials. However, it is unknown whether this effect depends on the length of the sensory fibers. This is an important issue, because most painful neuropathies are length-dependent.
  
  
  METHODS
  We conducted a study of 40 healthy subjects, half of whom were older than age 50 years. Nociceptive stimuli were delivered to the feet and thighs using a CO2 laser stimulator.
  
  
  RESULTS
  Detection and pain perception thresholds did not correlate with age. Latencies of N1, N2, and P2 correlated positively with age on the feet but not on the thighs, whereas the amplitude of N2-P2 decreased with age for both areas.
  
  
  CONCLUSIONS
  The effects of aging on latencies may reflect a distal loss of peripheral inputs and a length-dependent de-synchronization of the ascending nociceptive volley. Additional changes in peripheral and central processes may explain the diffuse decrease of N2-P2 amplitudes observed with aging.
authors.affiliation: Pain Center & Department of Neurology, CHU Saint-Etienne, 42055, Saint-Etienne, France; Central Integration of Pain Lab, INSERM U1028 &UMR 5292, Centre for Neuroscience of Lyon, University Claude Bernard of Lyon & University Jean Monnet, 42023, Saint-Etienne, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Creac'H
authors.forename: Alexandre
authors.initials: A
authors.lastname: Bertholon
authors.forename: Philippe
authors.initials: P
authors.lastname: Convers
authors.forename: Luis
authors.initials: L
authors.lastname: Garcia-Larrea
authors.forename: Roland
authors.initials: R
authors.lastname: Peyron
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D066331:Laser-Evoked Potentials / Q000502:physiology*; D054020:Lasers, Gas; D035002:Lower Extremity / Q000294:innervation; D008297:Male; D008875:Middle Aged; D058748:Pain Perception / Q000502:physiology; D017288:Pain Threshold / Q000502:physiology; D011930:Reaction Time / Q000502:physiology
keywords: LEPs; aging; elderly; heat pain; laser evoked potentials; nociceptive thresholds