Abnormal brain processing of pain in migraine without aura: A high-density EEG brain mapping study

Abstract

In the present study we used high-density EEG brain mapping to investigate spatio-temporal aspects of brain activity in response to experimentally induced muscle pain in 17 patients with migraine without aura and 15 healthy controls. Painful electrical stimuli were applied to the trapezius muscle and somatosensory-evoked potentials were recorded with 128-channel EEG with and without concurrent induced tonic neck/shoulder muscle pain. At baseline, the calculated P300 dipole for single stimuli was localized in the cingulate cortex. In patients, but not in controls, the dipole changed position from baseline to the tonic muscle pain condition (z = 29 mm vs. z = -13 mm, P < 0.001) and from baseline to the post-tonic muscle pain condition (z = 29 mm vs. z = -9 mm, P < 0.001). This may be the first evidence that the supraspinal processing of muscle pain is abnormal in patients with migraine without aura.

Altered processing of sensory stimuli in patients with migraine

“…126 This anterior shift of activation contrasts with the pos terior shift of LEPs observed during capsaicin induced neuropathic pain in healthy volunteers, 127 and with the caudal displacement of cortical evoked potentials in the cingulate gyrus after intramuscular nociceptive stimulation of the trapezius muscle in patients with migraine. 128 This difference with the data on LEPs can be explained by the different methodologies used, which involved stimulation of different nociceptive afferents. 129 Similarly to the cortical evoked potentials elicited by non noxious stimuli, LEPs 75,130 and CHEPs 131 show habituation deficits in patients with migraine between attacks.…”

Spatial aspects of pain modulation are not disrupted in adolescents with migraine

“…We hypothesized that adolescents with migraine would have lower CPM efficacy, when assessed at the trapezius, compared to healthy adolescents. The trapezius was chosen since it is a local area that has been widely used in previous CPM 27 and migraine studies, [28][29][30][31] possibly since it is a muscle trigger point that may be involved in migraine pathophysiology. 32 In addition, it is a convenient area for PPT assessment, which was an important consideration for our pediatric sample.…”

Comment on Castien et al. (2018) pressure pain thresholds over the cranio-cervical region in headache - a systematic review and meta-analysis

“…This is more than 2.5 years ago and an updated search would have identified at least one additional study [ 4 ] The search was limited to 3 databases (the protocol in PROSPERO says that originally 4 databases were anticipated for the search) and did not include (baseline data from) randomised controlled trials. Maybe this was the reason why so many studies were not included in the review that report pressure pain thresholds in headache populations [ 5 – 7 ]? …”