Impact of adverse childhood experiences on sensory thresholds in adults living with multimorbidity and chronic pain (the ACE-MAP study): protocol for an observational feasibility study

Introduction Exposure to adverse childhood experiences (ACEs) is associated with a range of poor long-term health outcomes, including multimorbidity and chronic pain. Epidemiological evidence underpins much of this relationship; however, psychophysical testing methods, such as quantitative sensory testing (QST), may provide valuable insights into potential mechanisms. Previous studies have shown inconsistent links between ACEs and QST, but the QST profiles of people with multimorbidity have not been reported. We hypothesise that exposure to ACEs is associated with lowered QST thresholds (ie, experience of pain with milder stimuli) and that this association is stronger in adults with multimorbidity and/or chronic pain. The ACE-MAP study is a cross-sectional feasibility study with the primary aim of assessing the feasibility and acceptability of the proposed study procedures. The secondary aim is to generate preliminary data to understand the impact of ACEs on QST thresholds.

Methods and analysis We plan to recruit 40 participants, with 10 in each of the following groups: (1) chronic pain with multimorbidity; (2) chronic pain without multimorbidity; (3) multimorbidity without chronic pain; and (4) controls. Participants will complete a series of questionnaires (including on ACEs, chronic pain and long-term conditions) and will then take part in QST assessments. The primary study outcomes will include measures of feasibility and acceptability of the proposed study design. The secondary study outcomes will include exploratory analysis on the relationship between ACEs and QST thresholds.

Ethics and dissemination The study was approved by the Scotland B Research Ethics Committee (reference: 24/SS/0031). Results from the study will be presented at scientific conferences, published in a peer-reviewed journal and shared with patients and members of the public through other media streams.