Temporal summation, conditioned pain modulation, pressure pain threshold and central sensitization symptoms in individuals with chronic migraine: cross sectional observational study

ABSTRACT

BACKGROUND AND OBJECTIVES  Chronic migraine is defined by attacks on 15 or more days per month, with at least eight of them presenting typical migraine characteristics, and is recognized as a central sensitization syndrome marked by somatosensory alterations and a pathophysiology that remains not fully understood. This study investigates the clinical presentation of somatosensory aspects in individuals with chronic migraine during the interictal phase compared to healthy individuals.

METHODS  This is a cross-sectional observational study conducted in individuals with chronic migraine and healthy individuals aged between 18 and 55 years. Measures: temporal summation (temporal summation test), conditioned pain modulation (conditioned pain modulation test), pressure pain threshold (algometer), central sensitization (Central Sensitization Inventory) and allodynia (12-item checklist of allodynia symptoms).

RESULTS  32 migraine individuals (MG) and 22 from the health control group (CG) were included in this study. In the temporal sum test, pain amplification showed a significant difference between groups MG and CG in all seconds analyzed. Pressure pain thresholds were significantly lower in the moments of three measurements in the MG compared to the CG in the conditioned pain modulation test. Pressure pain thresholds in the head, neck and right tibialis anterior muscles were significantly lower in the MG compared to the CG. Central Sensitization Inventory scores were equivalent to an average of 56/100 points, representing a severe level of these central sensitization symptoms with chronic migraine. Severe symptoms of allodynia were present in 52% of participants with chronic migraine.

CONCLUSION  When assessed in the interictal period, individuals with chronic migraine showed alterations in somatosensory aspects related to pain, identified by amplification of the magnitude of the pain response, deficits in endogenous pain inhibition mechanisms, profound mechanical hyperalgesia and allodynia.

Keywords:
Central nervous system sensitization; Chronic pain; Headache disorders; Migraine disorders; Pain measurement

HIGHLIGHTS

Chronic migraines are characterized by an amplification of the pain response, deficits in endogenous pain inhibition and mechanical hyperalgesia, with a high prevalence of symptoms of central sensitization and allodynia

Tools such as quantitative sensory tests map the somatosensory profile, deepening the understanding of the mechanisms underlying pain and aiding in the personalization of therapeutic strategies

Reduced efficiency in conditioned pain modulation, associated with cutaneous allodynia, demonstrates dysregulation in pain modulation mechanisms