Intuitively, one expects that pain, whether acute or chronic, will affect sleep quality. However, the relationship between pain and sleep is not fully understood. Pain has been widely reported to be associated with various measures indicative of sleep disturbance including reduced sleep efficacy, reduced total sleep time, delayed sleep onset, greater fragmentation of sleep, increased activity during sleep and more non-restorative sleep.[1-3] Despite the fact that many of these measures are highly inter-correlated, the effect of pain upon sleep quality is clearly substantial across several dimensions. A recent article by Axén (2016) reports the degree of sleep disturbance among 233 patients with lower back pain over 26 weeks.[4] This study proposes that tracking people with low back pain and measuring how it relates with their sleep, may promote a better understanding of its influence on the pain disorder.
The study’s method for collecting data should be of interest to clinicians and researchers alike. Participants received an automated text message (SMS) every Sunday with the question “How many days this previous week has your low back pain been bothersome, i.e., affected your daily activities or routines?” to which the participant responded on a scale of 0 to 7. An additional SMS was also included every month which asked the question “How many nights this previous week has your low back pain disturbed your sleep?” which also required a response on a scale of 0 to 7. In short, the SMS approach was designed to have the least intrusive effect on participants and arguably contributed to a high compliance rate for the study.
The results of this study supported previous findings on the relationship between pain and sleep. First, sleep disturbance was reported by 67% of participants (55% acute and 76% chronic pain, respectively). Second, only 13% of participants experienced several weeks in a row without lower back pain. Third, 25% of participants did not report a pain free week during the entire six months of the study. Finally, associations between reported days with low back pain and the number of nights with disturbed sleep in the subsequent week remained relatively stable throughout the experiment (ranging from r = .52 to r = .66).
The relative stability in the association between lower back pain and sleep disturbance is interesting, although it is also somewhat at odds with Axėn’s statement that “there is a need to understand the relationship of pain and sleep over time to adequately manage the pain disorder and its consequences”, since the association between pain and sleep in this study appears to be consistent over the time period measured. However, it should also be noted that the stability of the association between pain and sleep reported in this particular study is unlikely to be found among all chronic pain conditions.
With regard to the large body of literature on the effects of sleep disturbance on cognition and mood [5] and the growing body of literature indicating that sleep quality can affect the pain experience [3], an interesting follow-on to this study would be to look at the contribution of both sleep disturbance and chronic pain on neurocognitive functioning. Future study in this area should also consider documenting the types of sleep disturbance experienced by participants, in addition to accounting for common co-morbid sleep disorders such as insomnia and obstructive sleep apnoea syndrome. In conclusion, Axėn’s (2016) findings indicate that the relationship between chronic back pain and sleep disturbance is substantial and relatively stable. It is also plausible that clinicians treating patients with lower back pain could use a similar system to that employed by this study (text messages) to assess pain and sleep quality as part of their management process.
About Danny Camfferman
Danny is interested in the interaction between pain and sleep, and more specifically, the cortical activity associated with these processes. His research experience is diverse including, sleep disorders in children and adults, Prader Will syndrome, Australian Indigenous children’s sleep, childhood eczema, waking EEG markers of chronic pain and sleep deficits, thermoregulation, and nociceptive-sleep ERP components and arousal. Although his research is primarily centered on EEG methodologies, his love for technology will keep him open to new and innovative approaches in this area of study. Danny is married to Yoko and they have a feisty 11 year old daughter called Niko. Together, they enjoy house renovating, Iaido, camping, movies, furniture restoration, good food and their garden.
References
[1] van de Water, A.T., J. Eadie, and D.A. Hurley, Investigation of sleep disturbance in chronic low back pain: an age- and gender-matched case-control study over a 7-night period. Man Ther, 2011. 16(6): p. 550-6.
[2] Kelly, G.A., C. Blake, C.K. Power, et al., The association between chronic low back pain and sleep: a systematic review. Clin J Pain, 2011. 27(2): p. 169-81.
[3] Lautenbacher, S., B. Kundermann, and J.C. Krieg, Sleep deprivation and pain perception. Sleep Med Rev, 2006. 10(5): p. 357-69.
[4] Axen, I., Pain-related Sleep Disturbance: A Prospective Study With Repeated Measures. Clin J Pain, 2016. 32(3): p. 254-9.
[5] Goel, N., H. Rao, J.S. Durmer, et al., Neurocognitive consequences of sleep deprivation. Semin Neurol, 2009. 29(4): p. 320-39.