Inclusion criteria cases:
- nonspecific spinal pain (≥3 days per week and ≥3 months of chronic low back pain, failed back surgery syndrome > 3 years prior, chronic whiplash, or chronic non traumatic neck pain)
- aged between 18 and 65 years
- seeking care because of neck pain or low back pain
- native dutch speaker
- having insomnia: in the absence of other intrinsic sleep disorders and shift work, insomnia is defined as > 30 minutes of sleep latency and/or minutes awake after sleep onset for > 3 days / week for > 6 months
- living or working within a radius of 50 km around the test location
- not starting new treatments or medication and continuing their usual care 6 weeks prior to and during study participation (to obtain steady state)
- referring from analgesics, caffeine, alcohol or nicotine in the previous 48 h of the assessments
- nonspecific failed back surgery > 3 years are permitted
- not undertaking exercise (>3 metabolic equivalents) 3 days before the experiment
Exclusion criteria cases:
- severe underlying sleep pathology (identified through baseline data of polysomnography)
- neuropathic pain
- chronic widespread pain
- being pregnant or pregnancy (including giving birth) in the preceding year
- history of specific spinal surgery
- thoracic pain in absence of neck or low back pain
- shift workers
- present clinical depression
- BMI ≥ 30
Inclusion criteria controls:
- native dutch speaking
- 18 to 65 years of age
- having chronic nonspecific chronic spinal pain (≥3 days per week and ≥3 months of chronic low back pain, failed back surgery syndrome > 3 years prior, chronic whiplash, or chronic non traumatic neck pain)
- referring from analgesics, caffeine, alcohol or nicotine in the previous 48 h of the assessments
- not undertaking exercise (>3 metabolic equivalents) 3 days before the experiment
- No new medication 6 weeks prior to the assessment
- currently not undergoing any treatment (excl. medication) for chronic spinal pain
Exclusion criteria controls:
- specific medical conditions (neuropathic pain, specific neck of back surgery, osteoporotic vertebral fractures, or rheumatologic diseases)
- chronic widespread pain syndromes (fibromyalgia or chronic fatigue syndrome)
- having insomnia (in the absence of other intrinsic sleep disorders and shift work, insomnia is defined as > 30 minutes of sleep latency and/or minutes awake after sleep onset for > 3 days / week for > 6 months)
- severe underlying sleep pathology
- being pregnant or pregnancy in the preceding year
- thoracic pain in the absence of neck or low back pain
- diagnosed depression
- BMI over 30