Cephalalgia : an international journal of headache
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We investigated whether experimentally determined, suprathreshold pain sensitivity of pericranial musculature in patients with tension-type headache differs from that of migraine patients or from that of healthy subjects. Furthermore, we looked to see whether differences could be found in the effects of experimental pain induction on EMG activity of pericranial musculature and whether subgroups could be discovered with higher and lower pericranial pain sensitivity within the three diagnostic groups in terms of neurophysiological, psychological and clinical variables. In 20 patients with tension-type headache, 23 patients with migraine without aura, and 29 healthy individuals experimental pain was induced in the temporal muscle by mechanical pressure; pain sensitivity in the entire metrically subdivided suprathreshold pain sensitivity range was measured. ⋯ The results indicate that significant differences in the examined groups are found not in pain perception but in the processing or reaction to experimental headache stimuli. In patients with tension-type headache subgroups evolve based on pericranial pain sensitivity with quantitatively and/or qualitatively impaired reactions; for this reason diagnostic grouping according to the IHS classification seems to be pathophysiologically relevant. The intraindividual phasic comparison of pain reactions appears to be more important than the absolute interindividual tonic comparison.
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Levels of beta-endorphin in peripheral blood mononuclear cells have been studied as a new approach to investigating opioid tone in migraine and tension-type headache. Sixty-one patients with migraine without aura, 39 with migraine with aura and 23 with episodic tension-type headache were compared with 37 healthy controls. ⋯ A significant reduction in peripheral blood mononuclear cell beta-endorphin concentrations was observed in migraine patients with and without aura, but not in tension-type headache patients. Altered transmitter modulation to peripheral blood mononuclear cells may be the cause of this alteration, which could be part of a more diffuse opioid system derangement in migraine subjects.