title: A comparative study of cortical responses evoked by transcutaneous electrical vs CO(2) laser stimulation.
abstract: OBJECTIVE
  A novel non-invasive method for nociceptive electrical stimulation of the skin has been recently introduced by using a planar concentric stimulating electrode (CE). We compared the cortical potentials induced by a CE vs laser stimulator in healthy subjects using a multichannel recording.
  
  
  METHODS
  Cortical potentials were recorded in 11 healthy subjects by 54 scalp electrodes, stimulating the skin of the right hand and the right supra-orbital zone by the CE and laser stimulator settled two levels above the individual pain threshold.
  
  
  RESULTS
  The latency difference between N1, N2, and P2 evoked by the CE vs laser stimulator was larger than the receptor activation time of 40 ms and larger following stimulation of the upper limbs than of the head. The amplitudes and topographic distribution of the cortical waves did not differ between the two stimulation types.
  
  
  CONCLUSIONS
  A-beta fibre co-activation may be induced by CE electrodes, as suggested by latency gaps. Nevertheless, CE-evoked potentials showed similarity in amplitude, morphology and topographic representation with laser-induced ones.
  
  
  CONCLUSIONS
  At present, CE-evoked potentials cannot be considered a reliable measure of nociceptive pathway function.
authors.affiliation: Neurophysiopathology of Pain Unit, Neurological and Psychiatric Sciences Department, Aldo Moro University, Bari, Italy. m.detommaso@neurol.uniba.it
authors.forename: Marina
authors.initials: M
authors.lastname: de Tommaso
authors.forename: Roberto
authors.initials: R
authors.lastname: Santostasi
authors.forename: Vito
authors.initials: V
authors.lastname: Devitofrancesco
authors.forename: Giovanni
authors.initials: G
authors.lastname: Franco
authors.forename: Eleonora
authors.initials: E
authors.lastname: Vecchio
authors.forename: Marianna
authors.initials: M
authors.lastname: Delussi
authors.forename: Paolo
authors.initials: P
authors.lastname: Livrea
authors.forename: Zaza
authors.initials: Z
authors.lastname: Katzarava
mesh_terms: D000328:Adult; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006257:Head / Q000502:physiology; D006801:Humans; D054020:Lasers, Gas; D008297:Male; D008875:Middle Aged; D017288:Pain Threshold / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012879:Skin Physiological Phenomena; D013003:Somatosensory Cortex / Q000502:physiology*; D004561:Transcutaneous Electric Nerve Stimulation; D034941:Upper Extremity / Q000502:physiology; D055815:Young Adult