Physiotherapists' Placebo or Nocebo Communication Regarding VR in CMP

Rationale: Chronic musculoskeletal pain (CMP) is a common and disabling condition. Physiotherapy is the most frequently administered non-pharmacological treatment option for patients with CMP and recently virtual reality (VR) was introduced in physiotherapy care as a novel treatment modality. Proper communication about physiotherapy treatment (modalities) is important to improve treatment outcomes, by applying placebo effects enhancing communication and avoiding nocebo effects enhancing communication. However, yet is still unknown to what extent this applies to communication of physiotherapists about VR in patients with CMP. Objective: To determine the effect of physiotherapists' placebo or nocebo therapeutic communication about VR, on treatment credibility and expectation in patients with CMP Study design: Web-based randomized controlled trial. Study population: 100 participants Intervention: The placebo intervention group will be shown an educational video about VR, containing placebo effects enhancing verbal language. The nocebo intervention group will be shown an educational video about VR, containing nocebo effects enhancing verbal language. Primary study parameters: The primary study parameters are treatment credibility and treatment expectation. Treatment credibility and treatment expectations will be measured using the Dutch credibility and expectancy questionnaire (CEQ).