Unaltered intrinsic functional brain architecture in young women with primary dysmenorrhea

Lin-Chien Lee,Jen-Chuen Hsieh,Chia-Shu Lin,Yueh-Hua Chen,Chih-Che Chou,Intan Low,Li-Fen Chen,Hsiang-Tai Chao,Cheng-Hao Tu,Tzu-Chen Yeh,Chou-Ming Cheng,Wei-Chi Li

doi:10.1038/s41598-018-30827-6

Abstract

Primary dysmenorrhea (PDM), painful menstruation without organic causes, is the most prevalent gynecological problem in women of reproductive age. Dysmenorrhea later in life often co-occurs with many chronic functional pain disorders, and chronic functional pain disorders exhibit altered large-scale connectedness between distributed brain regions. It is unknown whether the young PDM females exhibit alterations in the global and local connectivity properties of brain functional networks. Fifty-seven otherwise healthy young PDM females and 62 age- and education-matched control females participated in the present resting-state functional magnetic resonance imaging study. We used graph theoretical network analysis to investigate the global and regional network metrics and modular structure of the resting-state brain functional networks in young PDM females. The functional network was constructed by the interregional functional connectivity among parcellated brain regions. The global and regional network metrics and modular structure of the resting-state brain functional networks were not altered in young PDM females at our detection threshold (medium to large effect size differences [Cohen’s d ≥ 0.52]). It is plausible that the absence of significant changes in the intrinsic functional brain architecture allows young PDM females to maintain normal psychosocial outcomes during the pain-free follicular phase.

Highlights

Primary dysmenorrhea (PDM), painful menstruation without organic causes, affects more than one-half of menstruating women worldwide[1]
Recent neuroimaging studies of PDM have disclosed the functional connectivity of the resting-state brain networks undergoes maladaptive or adaptive reorganizations in response to long-term dysmenorrhea
We examined the global and regional network metrics and modular structure of brain functional networks in young PDM females using networks constructed by parcellated cerebral regions according to the AAL and Harvard-Oxford cortical and subcortical probabilistic atlases

Summary

Introduction

Primary dysmenorrhea (PDM), painful menstruation without organic causes, affects more than one-half of menstruating women worldwide[1]. Previous studies showed long-term PDM is associated with hypo-connectivity of DMN-descending pain modulatory systems (DPMS)[11] and -salience network[12,13] and hyper-connectivity of DMN-executive control network[12] These reorganizations of functional connectivity, both within and across the resting-state brain networks, may underpin the pathophysiological mechanisms of PDM as well as the neural bases of associated sensory and affective elements[11,12,13]. In terms of the complex and multidimensional nature of chronic pain and its comorbidities (depression, sleep disorder, and cognitive dysfunction16), the maladaptive neuroplasticity of the brain in chronic pain disorders is not confined to the changes in certain brain regions and systems, but can be manifested in the topological organization of whole-brain networking[17] Chronic pain disorders, such as fibromyalgia[18], irritable bowel syndrome[19], chronic back pain[20], and migraine[21,22,23], exhibit altered large-scale connectedness between distributed brain regions. The integrity of the brain architecture is indicated by the degree of small-worldness and network efficiency[24]

Methods

Results

Discussion

Conclusion