Individuals with pain need more sleep in the early stage of mild traumatic brain injury

Abstract Objective Hypersomnia is frequently reported after mild traumatic brain injury (mTBI), but its cause(s) remain elusive. This study examined sleep/wake activity after mTBI and its association with pain, a comorbidity often associated with insomnia. Methods Actigraphy recording was performed for 7 ± 2 consecutive days in 56 individuals at 1 month post-mTBI (64% male; 38 ± 12 years), 24 individuals at 1 year post-mTBI (58% male; 44 ± 11years), and in 20 controls (50% male; 37 ± 12 years). Pain intensity and its effect on quality of life was assessed with a visual analogue scale and the Short Form Health Survey (SF-36) bodily pain subscale. Results Overall, few differences in sleep/wake patterns were found between mTBI patients and controls. However, individuals with higher percentages of mTBI with moderate-to-severe pain were found to require more than 8 hours of sleep per day (37% v s11%; p = 0.04) and to be frequent nappers (defined as those who took three or more naps per week) (42% vs 22%; p = 0.04) compared to those with mild or no pain at 1 month postinjury. Correcting for age and depression, The SF-36 score was found to be a significant predictor of sleep duration exceeding 8 hours per day at 1 month (odds ratio = 0.95; 95% confidence interval = 0.92−0.99; p = 0.01), but not at 1 year post-mTBI. Pain and increased sleep need (in terms of hours per day or napping frequency) were found to co-exist in as much as 29% of mTBI patients at 1 month postinjury. Conclusion Pain could be associated with more pronounced sleep need in about one-third of mTBI patients during early recovery. Unalleviated pain, found in more than 60% of mTBI patients, should therefore be looked for in all mTBI patients reporting new onset of sleep disorder, not only in those with insomnia.