Changes in cortical processing of pain in chronic migraine.

Abstract

OBJECTIVE:

The aim of this study was to perform a topographic and dipolar analysis of nociceptive-evoked responses obtained by laser stimulus under basal conditions in a cohort of chronic migraine (CM) patients, compared with migraine without aura (MWA) patients and noncraniofacial pain controls.

BACKGROUND:

An increased activation of cortical areas devoted to the emotional and attentive components of pain was previously found during the course of the migraine attack; it was more pronounced in patients reporting higher frequency of migraine.

METHODS:

Twenty-six outpatients were enrolled in the study; 16 fulfilled the criteria of CM, and 10 were affected by MWA. Fifteen noncraniofacial pain subjects were also selected. The pain stimulus was a CO2 laser pulses. The right-supraorbital zone was stimulated. Source localization analysis was performed on the most prominent laser-evoked potentials (LEPs) peak (P2) for each data set. The anatomical locations of the P2 sources were projected onto a standard normalized 3D MRI model.

RESULTS:

The CM group differed significantly from both MWA patients and controls for the x coordinate and from controls for the z coordinates. The P2 dipole localized in the rostral cingulate cortex in CM patients, lying in a more posterior location within the anterior cingulate cortex (ACC) in both controls and MWA patients. The x coordinate of the P2 dipole, expressing the postero-anterior location, was significantly correlated with frequency of headache.

CONCLUSIONS:

CM seems to be characterized by a distinctive pattern of cortical elaboration of pain, with a prevalent activation of the rostral portion of the ACC: our results suggest that this may be a predisposing factor to migraine chronicity.

• Authors: Marina de Tommaso, Luciana Losito, Olimpia Difruscolo, Giuseppe Libro, Marco Guido, Paolo Livrea
• Journal: Headache (Headache) Vol. 45 Issue 9 Pg. 1208-18 (Oct 2005) ISSN: 0017-8748 [Print] United States
• PMID: 16178951 (Publication Type: Comparative Study, Journal Article)

Topics

• Adult
• Cerebral Cortex (physiopathology)
• Chronic Disease
• Cohort Studies
• Evoked Potentials
• Female
• Humans
• Lasers
• Male
• Middle Aged
• Migraine Disorders (physiopathology)
• Migraine without Aura (physiopathology)
• Pain (physiopathology)
• Pain Measurement (methods)