Cephalalgia : an international journal of headache
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Normal heat pain threshold (HPT) and cold pain threshold (CPT) repeatability should be estimated in order to identify thermal allodynia in longitudinal studies, but such data are scarce in the literature. The aim of our study was to estimate normal HPT and CPT repeatability in the face, forehead, neck and hand. In addition, we reviewed briefly normative studies of thermal pain thresholds relevant for headache research. ⋯ The upper normal CPT limit varied between 24.5 degrees C and 29.7 degrees C. Lower HPT limits ranged between 35.5 degrees C and 40.8 degrees C. Quantitative sensory methods provide useful information about headache and pain pathophysiology, and it is important to estimate the normal test/retest repeatability range in follow-up studies.
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This study aimed to identify the cortical mechanisms underlying the processes of interictal dishabituation to experimental pain in subjects suffering from migraine with aura (MWA). In 21 subjects with MWA and 22 healthy controls, cortical responses to two successive trials of noxious contact-heat stimuli were analyzed using EEG-tomography software. When compared with controls, MWA patients showed significantly increased pain-evoked potential amplitudes accompanied by reduced activity in the orbitofrontal cortex (OFC) and increased activity in the pain matrix regions, including the primary somatosensory cortex (SI) (p < .05). ⋯ The activity changes in the OFC negatively correlated with lifetime headache duration and longevity (p < .05). Reduced inhibitory functioning of the prefrontal cortex is a possible cause for disinhibition of the pain-related sensory cortices in migraine. The finding of OFC hypofunction over the disease course is in keeping with current concepts of migraine as a progressive brain disorder.
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SUNCT syndrome (short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing) is a primary headache characterised by a high frequency of attacks associated with marked autonomic periocular signs and symptoms. Activation of the hypothalamus via the superior salivary nucleus is probably responsible for some of the autonomic involvement observed during SUNCT attacks. ⋯ Pupillometric studies were performed both in a basal condition (without anisocoria) and after instillation of phenylephrine (a drug with direct sympathomimetic activity) and pilocarpine (a parasympathetic agonist). The findings in this patient seem to indicate involvement of the ocular sympathetic supply in SUNCT, responsible for the mydriasis, and seem to strengthen the possibility that the autonomic phenomena in this syndrome vary with different levels of pain severity.
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Migraine and tension-type headache (TTH) can increase in frequency and transform from episodic to chronic forms. The process of transformation of these primary headaches is complex and involves multiple risk factors. In this cross-sectional and longitudinal population study, we aimed to investigate the relation of clinical characteristics of primary headaches to poor outcome: new-onset or persistent chronic headache (> or =180 days/year). ⋯ For pure TTH, unilateral headache, nausea and individual headache attack duration greater than 72 hours was associated with poor outcome. Pooled data univariate analysis revealed that nausea, daily use of acute headache medications, use of headache preventive medications and coexistent headaches were significant predictors of chronic headache in 2001(p<.05). In conclusion, our study demonstrates that certain clinical characteristics of headaches are associated with poor outcome but alone may not predict the chronification of migraine or TTH.