Study design: Pre-post cohort mixed factorial design.
Objective: Excessive daytime sleepiness (EDS) and chronic pain are major problems for people with spinal cord injury (SCI). However, the relationship between chronic pain and EDS requires clarification. The goal of the study was to determine associations between pain catastrophizing (PC) and pain intensity (PI) with EDS in adults with SCI.
Setting: New South Wales, Australia.
Methods: Participants included 45 adults with SCI and 44 able-bodied controls. The relationship between PI, PC, and EDS was explored by determining the influence of PC and PI on the performance of both groups in a behavioral test of EDS called the Oxford Sleep Resistance Test. PC and PI were assessed by self-report. The association between EDS, pain, and other relevant factors like fatigue and mood was established using multidimensional scaling in the SCI group data.
Results: PC was found to have a significant association with EDS, with 33.3% falling asleep in the SCI group with low PC, compared with 70% in those with high PC. Only 10% of the controls fell asleep regardless of PC. PI did not significantly influence EDS in either group. Multidimensional scaling showed EDS was closely related to PC, PI, pain interference, fatigue, and mood.
Conclusions: PC appears to be strongly associated with EDS in SCI. Findings suggest significant sleep benefits may occur in adults with SCI by treating cognitive biases like PC, as well as addressing associated factors like fatigue, pain interference, low mood, and so on.