High rates of PI and sleep apnea highlight the need to refer TMD patients complaining of sleep disturbance for polysomnographic evaluation. The association of PI and hyperalgesia at a nonorofacial site suggests that PI may be linked with central sensitivity and could play an etiologic role in idiopathic pain disorders. The association between sleep disordered breathing and hypoalgesia requires further study and may provide novel insight into the complex interactions between sleep and pain-regulatory processes.

Cross-sectional research in clinical samples, as well as experimental studies in healthy adults, suggest that the experiences of pain and sleep are bi-directionally connected. However, whether sleep and pain experiences are prospectively linked to one another on a day-to-day basis in the general population has not previously been reported. This study utilizes data from a naturalistic, microlongitudinal, telephone study using a representative national sample of 971 adults. Participants underwent daily assessment of hours slept and the reported frequency of pain symptoms over the course of one week. Sleep duration on most nights (78.0%) was between 6 and 9 hours, and on average, daily pain was reported with mild frequency. Results suggested that hours of reported sleep on the previous night was a highly significant predictor of the current day's pain frequency (Z= −7.9, p<.0001, in the structural equation model); obtaining either less than 6 or more than 9 hours of sleep was associated with greater next-day pain. In addition, pain prospectively predicted sleep duration, though the magnitude of the association in this direction was somewhat less strong (Z= −3.1, p=. 002, in the structural equation model). Collectively, these findings indicate that night-to-night changes in sleep affect pain report, illuminating the importance of considering sleep when assessing and treating pain.

Several recent reports suggest that pain-related catastrophizing is a risk factor for poor acute pain outcomes following surgical interventions. However, it has been less clear whether levels of catastrophizing influence longer-term postoperative outcomes. Data were analyzed from a relatively small number (n=43) of patients who underwent total knee replacement and were followed for 12 months after their surgery. Previous research has suggested that high levels of both catastrophizing and depression are associated with elevated acute postoperative pain complaints among patients undergoing knee surgery. In this sample, catastrophizing and depression at each of the assessment points were studied as prospective predictors of pain (both global pain ratings and pain at night) at the subsequent assessment point over the course of one year. The predictive patterns differed somewhat across measures of pain reporting; depressive symptoms were unique predictors of greater global pain complaints, while catastrophizing was a specific and unique predictor of elevated nighttime pain. While surgical outcomes following total knee replacement are, on average, quite good, a significant minority of patients continue to experience long-term pain. The present findings suggest that high levels of catastrophizing and depression may promote enhanced pain levels, indicating that interventions designed to reduce catastrophizing and depressive symptoms may have the potential to further improve joint replacement outcomes.