Central Processing of Acute Muscle Pain in Chronic Low Back Pain Patients: An EEG Mapping Study

Abstract

The presence of perceptual sensitization and related brain responses was examined in 14 chronic low back pain (CLBP) patients and 13 healthy controls comparable in age and sex. Multichannel EEG recordings and pain ratings were obtained during the presentation of 800 painful electrical intramuscular and intracutaneous stimuli each to the left m. erector spinae and the left m. extensor digitorum. Perception and pain thresholds were not significantly different between the two groups, though patients showed significantly more perceptual sensitization. Across all stimulation conditions, a larger EEG component 80 milliseconds after stimulation was observed in the CLBP group. No significant group differences were found for the N150. The component 260 milliseconds after stimulus onset was significantly smaller in the CLBP group. N80, N150, and perceptual sensitization were significantly positively correlated. These results indicate enhanced perceptual sensitization and enhanced processing of the sensory-discriminative aspect of pain, as expressed in the N80 component, in CLBP patients. This may be one neurophysiologic basis of sensitization and the chronicity process. The lower P260 component in the patients may be explained in terms of tonic pain inhibiting phasic pain or may be related to the affective distress observed in this patient group.

Central Sensitization and Altered Central Pain Processing in Chronic Low Back Pain

“…No differences in pain perception threshold and pain tolerance threshold between patients with chronic LBP and HCs were found when the noxious stimulation occurred at the finger, 32 the arm, 38 or other remote sites. 39 One study even observed significant higher pain thresholds in patients with chronic LBP when compared with HCs.…”

“…Evidence for enhanced temporal summation or wind-up comes from studies where pain stimulation is repeated 32,38,41,43 or where continuous stimulation is applied. 42 Mechanical, electrical, or thermal stimulation have been used to induce temporal summation (Table 1, wind-up).…”

Assessment and manifestation of central sensitisation across different chronic pain conditions

“…The concept of facilitated central gain in chronic LBP is also supported by an EEG mapping study (Diers et al, 2007).…”

Programa De Rehabilitación Integral en Pacientes Con Dolor Cronico De Espalda: Un Estudio De Caso

“…Se ha demostrado que los pacientes con lumbalgia crónica presentan variaciones estructurales y neuroquímicas de la actividad cortical (Diers et al, 2007) en especial la corteza prefrontal dorsolateral, el tálamo y la corteza orbitofrontal (Grachev, Fredrickson y Apkarian, 2000), el tronco cerebral y la corteza somatosensorial (Schmidt-Wilcke et al, 2006). Igualmente, se ha observado la disminución en el flujo de sangre en la sustancia gris periacueductal (Giesecke et al, 2006) redundando en hiperalgesia (Ole Kudsk, Claus Vinther y Kristian, 2009) y contribuye al desarrollo y mantenimiento del estado de dolor crónico (Apkarian, Baliki y Geha, 2009;Tracey y Bushnell, 2009).…”