Papers of the Week

Existing data demonstrate reduced delta power during sleep in patients with depression and chronic pain. However, there has been little examination of the relationship between delta power and pain-reports, or pain-catastrophizing. We recruited female participants (n=111) with insomnia and temporomandibular disorder, and measured nocturnal and daytime measures of pain and pain catastrophizing, and calculated relative nocturnal delta (0.5-4 Hz) power during sleep. We fit linear regression models, and further examined the moderating effect of depressive symptom severity. Lower relative delta power across the whole night was significantly associated with greater nocturnal pain (B = -20.276, p = 0.025, R = 0.214). Lower relative delta power during the first-third of the night, was associated with greater nocturnal pain (B = -17.807, p = 0.019, R = 0.217), next-day pain (B = 13.876, p = 0.039, R = 0.195), and next-morning pain (B = -15.751, p = 0.022, R = 0.198). Lower relative delta power during the final-third of the night was significantly associated with greater nocturnal (B = -17.602, p = 0.029, R = 0.207) and next-morning pain (3: B = -14.943, p = 0.042, R = 0.187). Depressive symptom severity did not moderate these relationships. Delta power was not significantly associated with nocturnal or daytime pain catastrophizing. These findings demonstrate that greater relative delta power during sleep is associated with lower nocturnal and next-day pain in patients with temporomandibular disorder. This data may guide the use of sleep interventions in clinical pain populations, with the aim of improving pain outcomes. PERSPECTIVE: This article presents data demonstrating an association between increased nocturnal delta power and reduced next-day pain. These findings may help promote interventions which aim to increase nocturnal delta power in clinical pain populations, with the goal of improving pain outcomes.