The preictal phase may be characterized by a reduction in habituation in patients with migraine, according to a study published in Cephalalgia. In addition, individuals with migraine may have greater sensitivity to pressure pain and a larger axon-reflex erythema compared with healthy controls.
A total of 33 healthy individuals with no history of headache, chronic pain, or neurologic disorder, 21 people with migraine, and 7 people with chronic tension-type headache (defined as ≥15 headache days per month) were enrolled in this study. Over a 5-day period, prodromal symptoms, electrically induced axon-reflex erythema, thresholds and suprathreshold pressure ratings, and electrical pain ratings in response to electrical stimulation were assessed during the interictal, preictal, and ictal phases of migraine.
The size of axon-reflex erythema in response to an electrical stimulation was assessed in the first trigeminal branch area. A larger axon-reflex erythema area was observed in patients with migraine vs healthy controls after electrical stimulation with a bipolar surface electrode (P =.0017). The size of the erythema was found to be larger during the preictal (P =.011) and ictal (P =.05) phases in patients with migraine vs healthy individuals in the post-hoc analysis. Pain pressure, as measured by an electronic algometer, was found to be lower in patients with migraine or chronic tension-type headache vs healthy controls (P =.027 and P =.023, respectively).
Changes in electrical pain thresholds were comparable during all phases of migraine. During the preictal phase, a 5-second electrical stimulation was reported as equally or more painful at the end vs the beginning of the stimulation (P =.008). Preictal values of electrical pain stimulation in participants with migraine were higher than those in the third and fourth sessions in healthy controls (P =0.004 and P =0.001, respectively).
The small cohort and the lack of age- and gender-matched healthy controls represent potential study limitations.
”[T]he method of testing habituation to nociceptive electrical stimulation might be used as a prediction for patients and clinician scientists to examine the effects of an early therapeutic intervention,” noted the investigators.
Strupf M, Fraunberger B, Messlinger K, Namer B. Cyclic changes in sensations to painful stimuli in migraine patients [published online August 12, 2018]. Cephalalgia. doi: 10.1177/0333102418793641