Abstract
OBJECTIVE: This experimental study aimed to assess pain sensitivity in low-frequency episodic migraine (LFEM), high-frequency episodic migraine (HFEM), and chronic migraine (CM) patients across the different phases of the migraine cycle. METHOD: In this observational, experimental study, clinical characteristics (diary and time from the last/next headache attack), and quantitative sensory testing (QST) (wind-up pain ratio (WUR) and pressure pain threshold (PPT) from the trigeminal area and PPT from the cervical spine) was performed. LFEM, HFEM, and CM were assessed in each of the 4 migraine phases (HFEM and LFEM: interictal, preictal, ictal, and postictal; CM: interictal and ictal) and compared vs. each other's (matched for the phase) and controls. RESULTS: A total of 56 controls, 105 LFEM, 74 HFEM, and 32 CM were included. No differences in QST parameters were observed between LFEM, HFEM, and CM in any of the phases. During the interictal phase and when comparing with controls the following were found: 1) LFEM had lower trigeminal PPT (p = 0.001) and 2) lower cervical PPT (p = 0.001). No differences were observed between HFEM or CM and healthy controls. During the ictal phase and when comparing with controls the following were found: HFEM and CM had 1) lower trigeminal PPTs (HFEM p = 0.001; CM = p < 0.001), 2) lower cervical PPT s (HFEM p = 0.007; CM p < 0.001), and 3) higher trigeminal WUR (HFEM p = 0.001, CM p = 0.006). No differences were observed between LFEM and healthy controls. During the preictal phase and when comparing with controls the following were found: 1) LFEM had lower cervical PPT (p = 0.007), 2) HFEM had lower trigeminal (p = 0.013) and 3) HFEM had lower cervical (p = .006) PPTs. During the postictal phase and when comparing with controls the following were found: 1) LFEM had lower cervical PPT (p = 0.003), 2) HFEM had lower trigeminal PPT (p = 0.005), and 3) and HFEM had lower cervical (p = 0.007) PPTs. CONCLUSION: This study suggested that HFEM patients have a sensory profile matching CM better than LFEM. When assessing pain sensitivity in migraine populations, the phase with respects to headache attacks is of utmost importance and can explain the inconsistency in pain sensitivity data reported in the literature.