The mechanical punctate pain threshold (MPPT), defined as the lowest intensity perceived as painful during sensory testing, is determined by headache frequency and migraine phases, according to study results published in Cephalalgia. These pain thresholds may be used to predict the next headache attack in patients with migraine.
Quantitative sensory testing (QST) allow assessment of sensitivity to cutaneous stimuli and processing of sensory stimuli. While QST has been extensively evaluated in patients with migraine, the results are mixed and limited data are available specifically on changes in punctate pain thresholds in this population. The goal of this study was to assess the effects of headache frequency and migraine phases on pain sensitivity using heat-, cold-, and mechanical punctate-induced pain stimuli.
The study included patients with chronic or episodic migraine and sex- and age-matched health controls without migraine or other primary headaches. All migraine patients were not using migraine preventive medications. Study participants underwent QST, including heat-, cold-, and mechanical punctate pain thresholds at the supraorbital area and the forearm dermatomes. Headache diaries were used to document headaches at baseline and after QST to determine headache frequency and the migraine phases of the testing day.
The cohort included 104 migraine patients (mean age 35.7 years, 85 women) and 32 healthy controls (mean age 37.8 years, 27 women). Of these, 92 migraine patients completed the study, including 64 patients with episodic migraine and 28 with chronic migraine.
Patients with episodic migraine had higher MPPTs compared with subjects with chronic migraine in both dermatomes and compared with healthy controls in the supraorbital dermatome. There were no differences in pain thresholds between those with chronic migraine and healthy controls. Heat- and cold- punctate stimuli were not significantly different between groups.
In patients with episodic migraine, but not among those with chronic migraine, there was a negative correlation between MPPTs in both dermatomes with headache frequency, as MPPTs declined gradually with increasing headache frequency and reached nadir.
During the interictal phase, patients with migraine exhibited significantly higher MPPTs in both dermatomes, compared with the preictal, ictal and postictal phases. Furthermore, MPPTs were highest in patients with episodic migraine during the interictal phase and declined at the preictal phase. They remained low during ictal and postictal phases.
Significant predictors of MPPTs in both dermatomes included migraine phase, followed by headache frequency, these variables independently explained 29.7% and 38.9% of the variance in MPPTs in the supraorbital and forearm dermatomes, respectively.
The researchers acknowledged several study limitations, including the cross-sectional design, relatively small number of patients in the postictal phase, and limited generalizability as the data are based on a single-center, hospital-based study.
“[O]ur data suggest that MPPT is determined by headache frequency and migraine phases, and MPPTs decline when migraine patients approach ictal stage or their headache become frequent. However, future research, including a longitudinal study, is warranted to confirm our study findings,” concluded the researchers.
Pan LH, Wang YF, Lai KL, et al. Mechanical punctate pain threshold is associated with headache frequency and phase in patients with migraine [published online May 16, 2020]. Cephalalgia. doi:10.1177/0333102420925540