Sense to Act: Pilot Randomized-controlled Trial of an Interoceptive Sensibility Intervention for Musculoskeletal Pain

Background: Interoceptive sensibility (IS), the self-reported experience of internal states, involves individuals' capacity to sense, interpret, integrate, and regulate their own bodily information. Disruptions in interoceptive processes are often associated with various health conditions, including mental illness and chronic pain (CP). Individuals with chronic musculoskeletal pain present disruptions in IS associated with worse pain adjustment.

While there is a growing body of research testing interoceptive-based interventions on both healthy and clinical samples, interventions specifically tailored for individuals with CP are limited. Furthermore, despite evidence that interventions such as mindfulness or meditation improve IS in incividuals with CP, the mechanisms contributing to enhanced pain-related outcomes remain unknown. Additionally, in Portugal, there is a lack of cost-effective interventions for CP in both public health services and the community.

This study aims to address these gaps by evaluating the feasibility of a program designed for a community setting. The program is specifically developed to enhance IS, potentially improving pain adjustment in individuals with chronic musculoskeletal pain - one of the most prevalent and burdensome types of pain globally. The study compares a group receiving an interoception-based intervention, intending to improve IS, against a control group on a waiting list, examining the intervention's acceptability, feasibility, appropriateness, and estimated treatment effects.

Method: The recruitment process will be conducted through the study website, providing information about the research team, study objectives, and general details about the intervention structure and session schedules. Potential participants must register on the website to enroll in the study. Measurements will be collected anonymously and online (via Qualtrics) using self-report questionnaires at four points in time: before (T0), in the middle (T1), at the end (T2), and one month after the intervention (T3). Additionally, participants in the intervention group will complete an anonymous evaluation checklist after each session and a final evaluation checklist assessing the study's acceptability, appropriateness, and feasibility. Block-stratified randomization of participants for each group (intervention/control), based on sex and geographical area (Lisbon/Évora), will be conducted using randomization software.

The intervention includes four stages addressing different IS skills with 8 weekly sessions (4-6 participants), each lasting 1.5 hours. These sessions will be delivered by two trained psychomotor therapists with clinical experience, supplemented by daily home exercises. To ensure fidelity of the procedures during sessions, recordings will be made for later review (therapists cross-confirm each other's sessions).