title: Brain morphological changes associated with cyclic menstrual pain.
abstract: Primary dysmenorrhea (PDM) is the most prevalent gynecological disorder for women in the reproductive age. PDM patients suffer from lower abdominal pain that starts with the onset of the menstrual flow. Prolonged nociceptive input to the central nervous system can induce functional and structural alterations throughout the nervous system. In PDM, a chronic viscero-nociceptive drive of cyclic nature, indications of central sensitization and altered brain metabolism suggest a substantial central reorganization. Previously, we hypothesized that disinhibition of orbitofrontal networks could be responsible for increased pain and negative affect in PDM. Here, we further tested this hypothesis. We used an optimized voxel-based morphometry (VBM) approach to compare total and regional gray matter (GM) increases and decreases in 32 PDM patients with 32 healthy age and menstrual cycle matched (peri-ovulatory phase) controls. Abnormal decreases were found in regions involved in pain transmission, higher level sensory processing, and affected regulation while increases were found in regions involved in pain modulation and in regulation of endocrine function. Moreover, GM changes in regions involved in top-down pain modulation and in generation of negative affect were related to the severity of the experienced PDM pain. Our results demonstrate that abnormal GM volume changes are present in PDM patients even in the absence of pain. These changes may underpin a combination of impaired pain inhibition, increased pain facilitation and increased affect. Our findings highlight that longer lasting central changes may occur not only in sustained chronic pain conditions but also in cyclic occurring pain conditions.
authors: Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan Integrated Brain Research Unit, Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan Brain Research Center, National Yang-Ming University, Taipei, Taiwan Department of Obstetrics and Gynecology, Taipei Veterans General Hospital, Taipei, Taiwan Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan Department of Computer Science, National Chiao Tung University, Hsinchu, Taiwan Department of Biomedical Imaging and Radiological Science, National Yang-Ming University, Taipei, Taiwan Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan.
authors: Cheng-Hao
authors: CH
authors: Tu
authors: David M
authors: DM
authors: Niddam
authors: Hsiang-Tai
authors: HT
authors: Chao
authors: Li-Fen
authors: LF
authors: Chen
authors: Yong-Sheng
authors: YS
authors: Chen
authors: Yu-Te
authors: YT
authors: Wu
authors: Tzu-Chen
authors: TC
authors: Yeh
authors: Jiing-Feng
authors: JF
authors: Lirng
authors: Jen-Chuen
authors: JC
authors: Hsieh
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D001931:Brain Mapping; D016022:Case-Control Studies; D004412:Dysmenorrhea / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D010147:Pain Measurement / Q000379:methods; D011581:Psychological Tests; D013223:Statistics as Topic; D055815:Young Adult