The aim of the study is to evaluate treatment outcomes of Spinal Cord Stimulation. In the study each patient participates in four test sessions of 4-5 hours. Patients arrive for test days with their stimulation on. In each test session, baseline pain is first evaluated. Then, SCS is regulated (on/off) and patients evaluate their pain intensity immidiately and every 15 minutes during the test sessions. Patients are blinded to the treatment conditions during their participation in the study. At all times, patients can resume their usual treatment.

Inclusion Criteria:

• Patients (>18 years of age) with SCS implanted to treat chronic pain.
• Patients who consent to participation and can cooperate in the study.
• Use of continuous paresthesia-free SCS for minimum 6 months prior to participation in the study.
• Pain score of 7 or less on a 0-10 scale in the most painful area treated with SCS, rated upon inclusion.
• Patients not receiving other neuromodulation treatment.
• Patients who have not undergone changes in their (pain relevant) medication during the last 30 days (pro necessitate medication allowed).