title: Pain in prolonged disorders of consciousness: laser evoked potentials findings in patients with vegetative and minimally conscious states.
abstract: BACKGROUND
  Pain perception is currently an open question in patients suffering from prolonged disorders of consciousness. The aim of the present study was to examine nociceptive specific laser evoked responses (LEPs) in view of long-latency evoked potentials by non-painful electrical stimuli (SEPs) and auditory mismatch negativity (MM).
  
  
  METHODS
  Three vegetative state (VS), four minimal Conscious State (MCS) patients and 11 age- and sex-matched controls were examined. Evoked responses were obtained by 64 scalp electrodes, stimulating the dorsum of the right hand by noxious laser and innocuous electrical stimulus, according to normal controls subjective rating. An auditory paradigm for MM was also employed.
  
  
  RESULTS
  The MM was present in all patients. The LEP vertex complex was recognizable in all cases, with a significant latency increase of both N2 and P2 which displayed changes of topographic representation. Late SEPs were absent in all patients except in one MCS case, who showed a significant N2 and P2 latency increase.
  
  
  CONCLUSIONS
  The results may suggest that high relevant stimuli may be processed even in patients with severe brain damage. Larger series and multimodal approaches may contribute to confirm that cortical arousal toward pain salience may be a primary function for life persistence.
authors.affiliation: Dipartimento di Neuroscienze e Organi di Senso, Università di Bari Aldo Moro, Piazza Giulio Cesare 11, Bari, Italy. marina.detommaso@uniba.it
authors.forename: Marina
authors.initials: M
authors.lastname: de Tommaso
authors.forename: Jorge
authors.initials: J
authors.lastname: Navarro
authors.forename: Katia
authors.initials: K
authors.lastname: Ricci
authors.forename: Marta
authors.initials: M
authors.lastname: Lorenzo
authors.forename: Crocifissa
authors.initials: C
authors.lastname: Lanzillotti
authors.forename: Fabio
authors.initials: F
authors.lastname: Colonna
authors.forename: Maurizio
authors.initials: M
authors.lastname: Resta
authors.forename: Giulio
authors.initials: G
authors.lastname: Lancioni
authors.forename: Paolo
authors.initials: P
authors.lastname: Livrea
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D005071:Evoked Potentials; D005260:Female; D006179:Gyrus Cinguli / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D058748:Pain Perception; D018458:Persistent Vegetative State / Q000503:physiopathology*; D011930:Reaction Time