Master Your Sleep
Sleep Posture and Waking Spinal Symptoms - Clinical Research
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Clients spend 1/3 of their life sleeping, so what happens at night is critical to optimising their ability to recover - both physical and mental. While we regularly discuss with clients their diurnal load, when it comes to advising them about rehabilitation, there is a big gap in our understanding regarding nocturnal load, and our research has shown that we can’t rely on the self-report of our clients to accurately inform us of their sleep postures.
One of the main issues to date has been the lack research examining sleep posture and waking spinal symptoms. Our group conducted a scoping review titled Identifying relationships between sleep posture and non-specific spinal symptoms in adults that was published in BMJ Open in 2019 and we found only 4 articles addressing this topic. Not much on which to base clinical decisions! One of the reasons for this was the lack of a low-cost, portable method to assess sleep posture, especially in the home environment, which is where all the action is. As clinicians advising clients, we were especially interested in the plausible biomechanical load that clients' spine receive at night, with the key movements associated with rotation and extension.
My PhD focuses on sleep postures and their effect on waking symptoms and quality of sleep; identifying potentially provocative and non-provocative sleep postures and the equipment we can use to assess sleep posture. The first part of this process was a pilot study to gain some understanding of this relationship and how we could measure sleep posture in our clients' normal sleep environment.
Our pilot study (n=15) was a sample of convenience (whoever we could convince to have cameras set up in their bedroom!). It showed that people are not able to self- report their sleep posture accurately (hence the need to video them) and while not statistically significant, it was noted that participants who spent greater periods of time in supportive side lying, had less mornings with symptoms per month than those that slept in provocative side lying. This gave us plausible reason to continue to pursue this idea of biomechanical load influencing waking spinal symptoms.
We determined our recording protocol was robust and effective with good footage obtained under sometimes ‘challenging’ environments with children, pets and camera failure being some of the issues. Other technical issues with equipment and sleep posture classifications were ironed out.
Sleep posture is classically described as supine, prone and everything else is side lying. Under this classification, we spend approximately 70% of sleep time in side lying. A problem with this classification structure is that it doesn’t account for the wide variety of side lying sleep postures, some being potentially provocative on spinal load, while others are not. For this reason, we wanted to subclassify the broad side lying category based upon spinal loading into two sub categories, provocative and supportive side lying. With the footage obtained, we are able to accurately identify the cardinal sleep postures and the new sub-classified provocative and supportive side lying postures. This research was published in 2016 and titled Examining the Relationship between Sleep Posture and Morning Spinal Symptoms in the Habitual Environment Using Infrared Cameras.
Determining the validity and reliability of equipment that assesses sleep posture in the home environment had not been done before, especially when focusing on the possible biomechanical effects of spinal rotation and extension inside lying. We created a ten minute video of sleep postures under different conditions of bed coverings (none, sheet, sheet + duvet) to simulate a realistic home situation, and different lighting (natural light and infra red light). Unique to our protocol was the use of two cameras in two different viewing planes. This video was viewed by 20 health professionals and each sleep postures was scored. We found both the intra- and inter-rater reliability were excellent. Meaning, clinicians can use this protocol to accurately assess sleep posture in the home environment. This paper is titled Examining the reliability and validity of a portable sleep posture assessment protocol, using infrared cameras, under a variety of light and bed cover situations in the home environment and published in WORK: A Journal of Prevention, Assessment & Rehabilitation.
We have subsequently taken this protocol and used it in a cross sectional study to compare the sleeping postures of people with neck or low back pain and a control group. In combination with sleep data captured using the previously validated recording protocol, to better understand relationships between sleep posture and waking symptoms. we have used validated quality of life, quality of sleep and spinal disability questionnaires. Data has been collected and analysed, and has been submitted as manuscript for publication submission (Feb 2021).
Most recently, we introduced a educational package in a longitudinal study of symptomatic participants (neck and low back pain), to determine if participants are able to change their sleep posture, and if they can, what changes are noted in their validated baseline quality of life, quality of sleep and spinal disability questionnaires. Data has been collected and analysed, and will be written for manuscript submission or conference presentation.
Available in 2021, to assist clinicians translate this research into actionable clinical practice, key information from this research will be combined with sleep hygiene training, cognitive behaviour therapy training and validated outcome questionnaires and presented as the The Sleep Mastery online course. If you are an early adopter of new research, you can express your interest in this course here.