title: Cortical Responsiveness to Nociceptive Stimuli in Patients with Chronic Disorders of Consciousness: Do C-Fiber Laser Evoked Potentials Have a Role?
abstract: It has been shown that the presence of Aδ-fiber laser evoked potentials (Aδ-LEP) in patients suffering from chronic disorders of consciousness (DOC), such as vegetative state (VS) and minimally conscious state (MCS), may be the expression of a residual cortical pain arousal. Interestingly, the study of C-fiber LEP (C-LEP) could be useful in the assessment of cortical pain arousal in the DOC individuals who lack of Aδ-LEP. To this end, we enrolled 38 DOC patients following post-anoxic or post-traumatic brain injury, who met the international criteria for VS and MCS diagnosis. Each subject was clinically evaluated, through the coma recovery scale-revised (CRS-R) and the nociceptive coma scale-revised (NCS-R), and electrophysiologically tested by means of a solid-state laser for Aδ-LEP and C-LEP. VS individuals showed increased latencies and reduced amplitudes of both the Aδ-LEP and C-LEP components in comparison to MCS patients. Although nearly all of the patients had both the LEP components, some VS individuals showed only the C-LEP ones. Notably, such patients had a similar NCS-R score to those having both the LEP components. Hence, we could hypothesize that C-LEP generators may be rearranged or partially spared in order to still guarantee cortical pain arousal when Aδ-LEP generators are damaged. Therefore, the residual presence of C-LEP should be assessed when Aδ-LEP are missing, since a potential pain experience should be still present in some patients, so to properly initiate, or adapt, the most appropriate pain treatment.
authors.affiliation: IRCCS Centro Neurolesi Bonino-Pulejo, Messina, Italy.
authors.forename: Antonino
authors.initials: A
authors.lastname: Naro
authors.affiliation: IRCCS Centro Neurolesi Bonino-Pulejo, Messina, Italy.
authors.forename: Margherita
authors.initials: M
authors.lastname: Russo
authors.affiliation: IRCCS Centro Neurolesi Bonino-Pulejo, Messina, Italy.
authors.forename: Antonino
authors.initials: A
authors.lastname: Leo
authors.affiliation: IRCCS Centro Neurolesi Bonino-Pulejo, Messina, Italy.
authors.forename: Carmela
authors.initials: C
authors.lastname: Rifici
authors.affiliation: IRCCS Centro Neurolesi Bonino-Pulejo, Messina, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Pollicino
authors.affiliation: IRCCS Centro Neurolesi Bonino-Pulejo, Messina, Italy.
authors.forename: Placido
authors.initials: P
authors.lastname: Bramanti
authors.affiliation: IRCCS Centro Neurolesi Bonino-Pulejo, Messina, Italy.
authors.forename: Rocco Salvatore
authors.initials: RS
authors.lastname: Calabrò
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D002540:Cerebral Cortex / Q000503:physiopathology*; D002908:Chronic Disease; D003244:Consciousness Disorders / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D066331:Laser-Evoked Potentials; D008297:Male; D036421:Nerve Fibers, Unmyelinated; D059225:Nociception; D055815:Young Adult