Neural oscillations and brain connectivity in females with chronic low back pain and comorbid insomnia

Sleep disturbance is a common comorbidity in individuals with chronic low back pain (CLBP), leading to greater functional impairments and poorer prognosis. Despite a strong association between CLBP and sleep, the neurophysiological mechanisms linking these two conditions remain unclear. As resting-state brain activity can reflect underlying neurophysiological states, this case-control study aimed to explore the spontaneous resting brain activity associated with CLBP and insomnia. One hundred females were enrolled and categorized into four subgroups: (1) non-specific CLBP and insomnia (CLBP+I, n = 25); (2) non-specific CLBP alone (CLBP+, n = 25); (3) insomnia alone (Insomnia+, n = 25); and (4) controls without non-specific CLBP nor insomnia (Controls, n = 25). Participants completed clinical questionnaires and underwent resting-state electroencephalography (EEG) recordings. DISCOVER-EEG was used for preprocessing and extracting physiological brain function features automatically. CLBP+I exhibited disrupted functional connectivity at the theta band across brain networks and enhanced beta band information processing compared to other groups, reflecting brain network imbalances driven by the combined effects of CLBP and insomnia. Additionally, insomnia was independently associated with aberrant functional connectivity in CLBP+I, even after accounting for pain-related and psychological factors. These findings provide new insights into the neurophysiological basis of CLBP with comorbid insomnia and lay a foundation for developing biomarkers and improving treatment strategies for this complex condition. Perspective: Distinct neurophysiological signatures in females with comorbid chronic low back pain and insomnia indicate unique brain changes in this population. Future studies should determine if these neurological signatures can predict prognosis or responses to treatment.