title: Laser-evoked potentials habituation in fibromyalgia.
abstract: Abnormalities of central pain processing play an important role in the pathophysiology of fibromyalgia (FM). The aims of the present study were to: 1) evaluate habituation of laser-evoked potentials (LEP) to repeated painful stimulation of 1 tender and 2 nontender points; and 2) determine correlations between LEP abnormalities and major clinical features of FM. Fourteen consecutive FM outpatients and 13 normal controls were included. LEP were recorded from scalp designations Fz, Cz, Pz, T3, and T4. The dorsum of the right hand, the right supra-orbital zone, and the right knee (a tender point in all patients) were subjected to repeated CO2 laser stimuli. For each stimulation site, recordings were obtained for 3 consecutive series of 20 stimuli. The 3 main findings in FM patients were: 1) an increased amplitude of vertex LEP and subjective laser pain; 2) decreased habituation of vertex LEP and subjective laser pain; and 3) a correlation between reduced N2 wave habituation and the severity of self-reported depressive symptoms. As with other chronic pain syndromes, the pathophysiology of FM may involve a generalized increase in the perception of painful stimuli and reduced habituation of the sensory cortex.
  
  
  CONCLUSIONS
  Reduced habituation of cortical responses to laser stimuli in FM patients suggests alterations in the pattern of cortical excitability. This is facilitated by depressive symptoms and abnormalities in central neurotransmission. These findings provide further support for the use of medications with effects on the central nervous system in the management of FM.
authors.affiliation: Department of Neurological and Psychiatric Sciences, Neurophysiopathology of Pain Unit, Bari University, Policlinico, Piazza Giulio Cesare 11, Bari, Italy. m.detommaso@neurol.uniba.it
authors.forename: Marina
authors.initials: M
authors.lastname: de Tommaso
authors.forename: Antonio
authors.initials: A
authors.lastname: Federici
authors.forename: Roberto
authors.initials: R
authors.lastname: Santostasi
authors.forename: Rita
authors.initials: R
authors.lastname: Calabrese
authors.forename: Eleonora
authors.initials: E
authors.lastname: Vecchio
authors.forename: Giovanni
authors.initials: G
authors.lastname: Lapadula
authors.forename: Fiorenzo
authors.initials: F
authors.lastname: Iannone
authors.forename: Paolo
authors.initials: P
authors.lastname: Lamberti
authors.forename: Paolo
authors.initials: P
authors.lastname: Livrea
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D005356:Fibromyalgia / Q000503:physiopathology*; D006801:Humans; D007834:Lasers; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement