Structural and functional connectivity of the posterior default mode network is associated with sleep disturbance rather than pain in the Twin sub-study of the MAPP Research Network

The neurophysiological underpinnings of chronic pain and sleep disturbances, which are commonly comorbid are not well understood. Investigation of common structural and functional brain network alterations of sleep disturbance in the setting of chronic pain may shed light on common mechanisms and improve specificity of treatment for these conditions. Our study examines the association between sleep parameters (including sleep duration, sleep difficulty, and sleep chronotype), pain phenotype, and brain structural and functional connectivity in individuals with chronic pelvic pain by leveraging data from the Twin Studies of the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network. Participants (n= 34 pairs) completed extensive clinical phenotyping and 3T MRI, including resting-state functional MRI (rs-fMRI), diffusion tensor imaging (DTI), and subjective sleep assessments. We observed significant differences in total sleep time (420 {+/-} 58 min vs. 466 {+/-} 61 min) and sleep difficulty (study-specific Likert scale 0-3: 1.35 {+/-} 0.81 vs. 0.95 {+/-} 0.68) among individuals with chronic pelvic pain compared to those without chronic pelvic pain, with sleep difficulty being associated with altered default mode network (DMN) connectivity. No associations were found with the salience network (SN), a network implicated in chronic pain. Additionally, increased total sleep time was associated with decreased posterior callosal white matter integrity. These findings underscore the complex interplay between chronic pain and sleep disturbances and have implications for distinct treatment approaches for patients with comorbid pain and sleep disorders.