Sleep, Pain and Function in People With Chronic Spinal Pain and Comorbid Insomnia

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 …