title: Laser-Evoked Potentials in Fibromyalgia: The Influence of Greater Occipital Nerve Stimulation on Cerebral Pain Processing.
abstract: OBJECTIVE
  Fibromyalgia causes widespread musculo-skeletal pain in the four quadrants of the body. Greater occipital nerve stimulation has recently shown beneficial effects in fibromyalgia patients on pain, fatigue, and mood disorders. Laser-evoked potentials (LEPs) are used for research to understand the pathophysiological mechanisms of pain and to evaluate the effects of pain treatment. In fibromyalgia patients, LEPs tend to have a higher N2 amplitude, a tendency to shorter latencies, and patients have a lower pain threshold. Greater occipital nerve stimulation might exert a modulation of the medial pain pathways processing the affective motivational components of pain (unpleasantness) as well as the descending pain inhibitory pathways (reducing pain), both of which are contributing to the N2P2 peak.
  
  
  METHODS
  To test this hypothesis, the authors performed LEPs in a group of fibromyalgia patients with and without greater occipital nerve stimulation.
  
  
  RESULTS
  Occipital nerve stimulation does not alter the amplitudes of the LEP recordings, although a significant difference in latencies can be seen. More specifically, latencies of the N2P2 increased in the condition after stimulation, and especially at the Pz electrode.
  
  
  CONCLUSIONS
  Our results suggest Occipital Nerve Stimulation (ONS) induces a modification of the balance between antinociceptive pain inhibitory pathways and pain-provoking pathways.
authors.affiliation: Department of Neurosurgery, University Hospital Antwerp, Edegem, Belgium.
authors.forename: Mark
authors.initials: M
authors.lastname: Plazier
authors.affiliation: BRAI2N, Sint Augustinus Hospital Antwerp, Edegem, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Ost
authors.affiliation: Department of Neurosurgery, University Hospital Antwerp, Edegem, Belgium.
authors.forename: Erwin
authors.initials: E
authors.lastname: Snijders
authors.affiliation: Department of Neurosurgery, University Hospital Antwerp, Edegem, Belgium.
authors.forename: Martijn
authors.initials: M
authors.lastname: Gilbers
authors.affiliation: Department of Neurosurgery, University Hospital Antwerp, Edegem, Belgium.
authors.forename: Tim
authors.initials: T
authors.lastname: Vancamp
authors.affiliation: BRAI2N, Sint Augustinus Hospital Antwerp, Edegem, Belgium.|BRAI2N, Department of Surgical Sciences, Section of Neurosurgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ridder
authors.affiliation: School of Behavioral and Brain Sciences, The University of Texas, Dallas, TX, USA.
authors.forename: Sven
authors.initials: S
authors.lastname: Vanneste
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004599:Electric Stimulation Therapy / Q000295:instrumentation / Q000379:methods*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D005356:Fibromyalgia / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D007834:Lasers; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013223:Statistics as Topic; D055815:Young Adult
keywords: C2 stimulation; fibromyalgia; greater occipital nerve stimulation; laser-evoked potentials; pain; pain processing