Long-term Monitoring of Sleep with Ear-EEG in Patients with Chronic Pain

Inclusion Criteria: For a subject to be eligible, all inclusion criteria must be answered "yes": * Understand and write Danish. * Pain present on most days or every day during the past 3 months. * Pain limits daily activities or work on some days, most days or every day during the past 3 months. * Pain intensity equal to or larger than 4 on 0-10 Numeric Rating Scale \[NRS\] within the last week. * Informed consent obtained before any study related activities. Exclusion Criteria: For a subject to be eligible, all exclusion criteria must be answered "no": * Previous stroke or cerebral haemorrhage and any other structural cerebral disease. * Obstructive sleep apnoea (Defined as yes to 3 or more questions in the STOP-BANG questionnaire for women and 4 or more questions for men). * Teeth grinding (bruxism). * Pregnancy or lactation (Pregnancy is screened for through self-reporting as no risks regarding pregnancy have been identified for the described study procedures). * Narrow or malformed ear canals or piercings, making ear-EEG infeasible. * Allergic contact dermatitis caused by metals or generally prone to skin irritation. * People judged incapable, by the investigator, of understanding the participant instruction or who are not capable of carrying through the investigation.