Trigeminal and cervical sensitization during the four phases of the migraine cycle in patients with episodic migraine

Objective: Assessing mechanical pain thresholds from trigeminal, cervical, and distal pain-free areas during the four phases of a migraine cycle in patients with episodic migraine (EM). Methods: This multicenter, cross-sectional, observational study conducted in Parma and Genoa’s Headache Centers assessed quantitative sensory tests during the four migraine phases in patients with EM compared to controls. Temporal summation of pain (TSP), static pressure pain threshold (sPPT), and mechanical pinprick pain threshold (MPT) were assessed from the trigeminal area, sPPT and dynamic PPT (dPPT) from the cervical area, sPPT and MPT over the hand, and sPPT from the tibialis anterior. Results: A total of 135 patients and 46 controls were included. TSP was facilitated in ictal EM (EM vs. controls: mean [standard deviation] 2.7 [2.0] vs. 1.4 [1.8]; p = 0.004); trigeminal sPPT and MPT were reduced in interictal (sPPT: 198.5 [79.3] kPa; p = 0.021; MPT: 12.6 [15.7] g; p = 0.001), preictal (sPPT: 200.6 [71.6] kPa; p = 0.033; MPT: 10.7 [12.4] g; p < 0.001), ictal (sPPT: 171.4 [95.9] kPa; p < 0.001; MPT: 7.3 [12.0] g; p < 0.001), and postictal EM (sPPT: 182.2 [76.3] kPa; p = 0.006; MPT: 10.1 [14.9] g; p = 0.001), compared to controls (sPPT: 238.3 [73.8] kPa; MPT: 21.9 [17.3] g). Cervical sPPTs and dPPT were reduced in interictal (sPPT upper cervical spine: 420.5 [176.7] kPa; p = 0.031; sPPT lower cervical spine: 458.6 [207.3] kPa; p = 0.002; dPPT: 4826.5 [2698.0] g; p < 0.001), preictal (sPPT upper cervical spine: 389.3 [133.4] kPa; p = 0.006; sPPT lower cervical spine: 450.8 [174.3] kPa; p = 0.005; dPPT: 4184.2 [2628.3] g; p < 0.001), ictal (sPPT upper cervical spine: 379.9 [205.6] kPa p = 0.003; sPPT lower cervical spine: 436.3 [271.1] kPa; p = 0.001; dPPT: 3838.3 [2638.7] g; p < 0.001), and postictal EM (sPPT upper cervical spine: 385.5 [131.6] kPa; p = 0.020; sPPT lower cervical spine: 413.0 [150.3] kPa; p = 0.002; dPPT: 4679.6 [2894.9] g; p = 0.001), compared to controls (sPPT upper cervical spine: 494.9 [171.5] kPa; sPPT lower cervical spine: 586.9 [210.8] kPa; dPPT: 7693.9 [2896.8] g). Preictal EM had reduced hand sPPT and MPT (sPPT: 248.8 [96.6] kPa vs. 319.8 [112.3] kPa; p = 0.006; MPT: 23.6 [12.2] g vs. 32.5 [14.4] g; p = 0.035), while EM in the other phases showed reduction in hand MPT (interictal: 22.3 [15.6] g vs. 32.5 [14.4] g; p = 0.002; ictal: 22.4 [17.0] g vs. 32.5 [14.4] g; p = 0.004; postictal: 24.2 [18.8] g vs. 32.5 [14.4] g; p = 0.003) without significant reduction in hand sPPT. No difference in sPPT over the tibialis anterior was found. Hand MPT was negatively correlated with longer disease duration (r = −0.25; p = 0.011) and hand sPPT was negatively correlated with higher drug usage (r = −0.31; p = 0.002). TSP during the ictal phase was positively correlated with the physical (r = 0.38; p = 0.040) and emotional headache-related disability (r = 0.53; p = 0.003). Conclusion: In all phases of the migraine cycle, patients with EM show signs of sensitization in the trigeminocervical area, with patients with the most prominent sensitization in the ictal phase. Signs of widespread sensitization were consistent in the preictal phase in patients with EM and in the subgroups of patients with EM with the longest disease duration and more usage of symptomatic drugs.