Effectiveness of Eye Movement Desensitization and Reprocessing (EMDR) Therapy in Rheumatoid Arthritis (RA) Patients With Persistent Pain Despite Inflammation Being Under Control: a Multiple Baseline Single Case Experimental Design Study Across Ten Cases

Rationale: Around 20% of rheumatoid arthritis (RA) patients have persistent pain, despite having well-controlled disease activity. There is a significant overlap in underlying mechanisms between post-traumatic stress disorder (PTSD) and persistent pain. Eye Movement Desensitization and Reprocessing (EMDR) is a proven effective treatment for PTSD and evidence is growing that it may also be effective for persistent pain. Objective: To assess the feasibility and estimate the effectiveness of EMDR in RA patients with persistent pain despite inflammation being under control.

Study design: A multiple-baseline single-case experimental design (SCED) across three time series. Participants will be randomized to one of the three time series. Within the time series the start of the intervention is randomly determined. Four participants will be assigned to the shortest, three to the medium and three to the longest baseline length. The SCED study consists of a baseline phase (A1), intervention phase (B), post-treatment phase (A2), follow-up phase 1 (A3), and follow-up phase 2 (A4).

Study population: Subjects are RA patients > 18 years with low disease activity (DAS28<3.2) at >2 measurements over the previous 12 months and concurrent elevated pain scores (NRS-pain>6).

Intervention (if applicable): EMDR therapy consists of an intake and eight sessions of 90 minutes in total, performed according to the EMDR standard protocol, conducted by four psychologists, all are level-II trained, under the supervision of an EMDR Europe consultant. EMDR focuses on processing traumatic memories, pain-related memories, and current physical pain.

Main study parameters/endpoints: Primary endpoint for effectiveness is the pre-treatment phase A1 to post-treatment phase A2 difference in NRS pain intensity. Feasibility is examined by monitoring recruitment, dropout rates, and treatment satisfaction. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: If the therapy is effective, pain intensity decreases, additional physical complaints of RA decrease and participants experience less discomfort from their pain in daily life. EMDR therapy is an evidence-based treatment for PTSD and the reduction of posttraumatic stress favors the recovery of physical complaints. Participating in the study includes two conversations for inclusion (two times 60 minutes consisting of one telephone conversation and one face-to-face conversation), attending the EMDR therapy intake (one time 90 minutes) and sessions (eight times 90 minutes), and daily registration of complaints (about two minutes per day) via a smartphone application, completing the questionnaires (about 14-28 minutes at six specific time points during the study), and an exit conversation at six months follow up. Daily registration will take 18 to 20 weeks maximum. At the three- and six-month follow-up, participants will be asked to register daily for 14 days. EMDR sessions can be emotionally intense, but never are as challenging as living with unprocessed (traumatic) pain-related memories. There are no risks associated with EMDR therapy.