2. Pain catastrophizing and features of cortical response to painful stimuli in fibromyalgia

Abstract

Gamma Band Oscillations (GBO) after laser stimuli are currently considered a correlate of subjective pain perception. Habituation of laser evoked potentials (LEPs) is reduced in patients with central amplification of pain stimuli. To correlate LEPs habituation and GBO induced by laser stimulation with subjective pain rating and pain catastrophizing in patients with Fibromyalgia (FM) and controls. We recorded LEPs in 30 FM patients and 15 healthy controls by stimulating the dorsum of the right hand. At the end of each series, the perceived pain was rated on a visual pain analogue scale (VAS). All subjects were submitted to the Pain Catastrophizing Scale – Italian version (PCS-I). The FM patients showed reduced LEPs habituation and increased laser-related GBO. Both patterns correlated with the PCS-I, but not with subjective pain rating. LEPs habituation and GBO may be the expression of cortical mechanisms of nociceptive stimuli processing and exaggerated attentional orientation toward pain experiences.