Increase pain sensitivity during the four phases of the migraine cycle in patients with episodic migraine

Excerpt

Migraine is a complex disorder characterized by recurrent attacks of unilateral, pulsating, moderate to severe headache, with nausea, vomiting, photo-phobia, and/or phono-phobia, which are associated with cyclic changes in the excitability of cortical, subcortical, and brainstem areas [1]. Quantitative sensory testing (QST) has been used to assess sensitization in patients with episodic migraine (EM) and highlight cyclic changes in the pain thresholds in trigeminal, cervical, and pain-free areas during the attacks. It is still uncertain if signs of trigeminal, cervical, and widespread sensitizations are also present in the interictal phase of the migraine cycle [2]. The aims of our study were to (1) assess pain thresholds in trigeminal, cervical, and distal pain-free areas with different QST methods in subjects with EM, (2) compare the pain thresholds of patients with EM during the four phases of the migraine cycle to healthy controls, and (3) correlate the presence of signs of sensitization with the interval from the last and the next headache attack and with the attack clinical characteristics and headache-related disability. The study was approved by the ethics committees in the Ligurian Region (244/2018) and Area Vasta Emilia-Nord (18,305/2019). The study has in full been published. [3]. The present work is focused on the analysis of the variations in relation to the trend of the attacks. All patients signed an informed consent form. We recruited patients on the waiting list to receive their first visit to the Headache Centers of Genova and Parma (Italy), both men and women, aged between 18 and 65 with EM (with and without aura). Diagnosis of EM was done according the International Classification of Headache Disorders Criteria. Controls were healthy subjects with a maximum of two headache episodes per year that did not fulfill the criteria for migraine or any other primary headache and with no family history of migraine or other primary headaches. For each subject, general and headache-related characteristics were assessed. Patients used a daily updated diary recording the number of symptomatic drugs and the frequency, intensity, and duration of headache attacks. The Headache Disability Index (emotional HDI-E and physical HCI-P) was used to assess the headache-related disability. QST was assessed during the 4 migraine phases in patients with EM and compared to controls. Static pressure pain threshold (sPPT), mechanical pinprick pain threshold (MPT), and temporal summation of mechanical pinprick (wind-up ratio (WUR)) were assessed from the trigeminal area, sPPT and dynamic PPT (dPPT) from the cervical area, and sPPT and MPT over the hand. The examiner was kept blinded to the presence of headache for as long as possible. A linear regression model was used to compare QST results of patients at specific migraine phases to controls while adjusting for possible confounders. A total of 135 patients and 46 controls were included. …