Recruited individuals in the cohort undergoe adequate treatment of the sleep disorder initiated by the sleep specialist at the sleep clinic, and when subjects are considered well treated, the sleep investigation is repeated in connection with follow-up 2-4 months later. Sleep duration and physical activity are measured with an actigraph for 10 days after the first visit when sleep treatment was initiated and 10 days before the follow-up, when the sleep intervention is complete.

Treatment of sleep disorders is carried out according to lege artis at the sleep clinic at the Pain Center (obstructive sleep apnea syndrome, snoring, restless legs syndrom and periodic limb movements, circadian rhythm disorders, insomnia) and examination of pain intensity before (as part of the FINE study) and after treatment is carried out with pain assessment (quantitatory sensory testing and conditioned pain modulation as well as a new panel with inflammatory markers and lumbal puncture).

Adequate treatment of sleep disorders at Sleep clinic

Change in subjective sleep disturbance measured by Pittsburgh Sleep Quality Index, a self-rated questionnaire which assesses sleep quality and disturbances over a 1-month time interval. The measure consists of 19 individual items, creating 7 components that produce one global score. Every item is weighted on a 0-3 interval scale. The global PSQI score is then calculated by totaling the seven component scores, providing an overall score ranging from 0 to 21, where lower scores denote a healthier sleep quality.

measured by Visual Analog Scale, total scores range from 0 to 10 - with a higher score indicating more severe pain (VAS 0 no pain - VAS 10 severe pain)

Change in sleepiness measured by Epworth Sleepiness Scale, a self-administered questionnaire with 8 questions. Rate, on a 4-point scale (0-3), rik of falling asleep while engaging in eight different activities. The ESS score (the sum of 8 item scores, 0-3) can range from 0 to 24. The higher the ESS score, the higher daytime speepiness.

Change in objective sleep disturbance measured by 1-night ambulatory polysomnography. A polysomnogram is the gold standard test to help diagnose sleep disorders. It involves measuring brain wave activity, eye, and limb movements whilst monitoring the breathing pattern and pulse rate during sleep. It is a non-invasive test which requires several sensors and electrodes to be placed on specific points of the body.

Change in disease burden measured by Fibromyalgia Impact Questionnaire, a brief 10-item, self-administered instrument that measures physical functioning, work status, depression, anxiety, sleep, pain, stiffness, fatigue, and well being. A higher score indicates a greater impact of the syndrome on the person. Each of the 10 items has a maximum possible score of 10. The maximum possible score is 100.