Frequency-Specific Alterations in Brain Function in Patients with Primary Dysmenorrhea

Recent neuroimaging studies have found that brain function is abnormal in primary dysmenorrhea (PDM). The present study aimed to explore frequency-specific brain alterations and their occurrence in the PDM.Forty-seven patients with PDM and 36 matched healthy controls were enrolled in the study and underwent resting-state functional magnetic resonance imaging. The alterations in brain function in patients with PDM were assessed with different frequency filter bands (Slow5, Slow4, Slow3, and full low frequency) and a functional connectivity density (FCD) approach. The clinical significance of the altered FCD was then explored. Additionally, mediation analysis was used to detect the altered FCD-mediated clinical relationships in PDM.Frequency-specific FCD alterations have been observed in patients with PDM, especially in the central executive, default mode, and sensorimotor networks and in the hippocampus. The altered full low-frequency FCD in the hippocampus was associated with the duration of disease and pain severity scores. The altered Slow5 FCD in the second somatosensory area (S2) was associated with the severity of pain in PDM. Furthermore, the FCD in S2 mediated the duration associated with pain symptoms in PDM.The present study identified frequency-specific FCD alterations in PDM and suggested that the S2 area is a potential treatment target for PDM.