This study is a part of a larger project aiming to evaluate the neurobiological mechanisms underlying the relationship between sleep and pain in people with non-specific chronic low back pain. Specifically, this study aims to evaluate the neurobiological mechanisms underlying the relationship between chronic sleep disturbances and pain sensitivity in people with non-specific chronic low back pain and chronic insomnia.
18-60 years old.
Ability to speak and understand the Dutch Language.
Body mass index <30.
No smoking or nicotine use.
Shift worker.
Use of blood thinners.
(History of) Substance dependence/abuse.
Chronic pain conditions (≥3 months) other than chronic low back pain.
Participants across all study groups will be recruited from the broad area around Leuven, Belgium, via local flyers and social media. Participants with non-specific chronic low back pain and/or chronic insomnia will also be recruited from the pain and/or sleep center of UZ Leuven, Belgium, as well as via primary care units and patient support groups targeting people in the Leuven area. Participants will be recruited and stratified according to sex and age to enable matching to the primary group of interest (chronic low back pain and comorbid insomnia), and a majority of females (\~two thirds) will be recruited to better represent the sex-distribution within the population representative of this group.
Case-control
Cross-sectional
Real-life monitoring, experimental pain testing, brain imaging, blood and stool sampling.
Other interventionSee detailed study description and outcome measures.
Brain metabolite concentrations
Concentration of brain metabolites measured using single-voxel magnetic resonance spectroscopy in five regions of interest: (1) pregenual anterior cingulate cortex (midline); (2/3) right/left thalamus; (4/5) right/left anterior insula.
Brain-tissue microstructure diffusivity
Diffusivity data (diffusion-weighted signal) from different microstructural compartments within the brain (intra-axonal space, extra-axonal space, and free water) measured using diffusion-weighted magnetic resonance imaging.
Functional brain responses to evoked low back pain
Blood-oxygen-level-dependent (BOLD) signal acquired during an evoked low back pain task performed during functional magnetic resonance imaging sequence.
Manual pressure pain detection thresholds (mPDT)
Gradually increasing pressure (1 kgf/sec) applied using a manual pressure algometer (FPX50, Wagner Instruments, USA) until the first sensation of discomfort (mPDT) is (self-)reported. The measurement is repeated three times across six body sites: (1/2) right/left m. erector spinae; (3/4) right/left m. extensor carpi radialis; (5/6) right/left m. gastrocnemius.
Computerized pressure pain detection thresholds (cPDT)
Gradually increasing pressure (1 kPa/sec) applied via a computer-controlled blood pressure cuff (Nocitech, Aalborg University, Denmark) around the calf (dominant leg) until a first sensation of discomfort (cPDT) is rated.
Pre-scanning total sleep time
Polysomnography-derived total sleep time (i.e., min asleep from sleep onset to offset) from the night preceding the brain scanning.
Pre-scanning sleep efficiency
Polysomnography-derived sleep efficiency from the night preceding the brain scanning.
Self-reported (REDCap) mood state assessed via a short (32-item) version of the Profile of Mood States (POMS-32)
The POMS-32 is a short version of the original 65-item POMS questionnaire, which evaluates mood states across six dimensions: tension-anxiety, depression-dejection, anger-hostility, vigour-activity, fatigue-inertia, and confusion-bewilderment. Total scores for each subscale vary, with higher scores indicating greater intensity of the corresponding mood state.
Self-reported (REDCap) sleepiness assessed via the Karolinska Sleepiness Scale (KSS)
The KSS is a single-item questionnaire (i.e., scale) that measures subjective sleepiness at a specific moment in time. Scores range from 1 to 9, with higher scores indicating greater sleepiness.
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Vrije Universiteit Brussel
Lead sponsor
Research Foundation - Flanders (Fonds Wetenschappelijk Onderzoek)
Collaborator
Universitaire Ziekenhuizen KU Leuven
Collaborator
