Individual Patterns and Temporal Trajectories of Changes in Fear and Pain during Exposure In Vivo: A Multiple Single-Case Experimental Design in Patients with Chronic Pain.

Jente Bontinck,Jeroen R De Jong,Inge Timmers,Amanda L Kaas,Marlies Den Hollander

doi:10.3390/jcm11051360

Abstract

Exposure in vivo (EXP) is an effective treatment to reduce pain-related fear and disability in chronic pain populations. Yet, it remains unclear how reductions in fear and pain relate to each other. This single-case experimental design study attempted to identify patterns in the individual responses to EXP and to unravel temporal trajectories of fear and pain. Daily diaries were completed before, during and after EXP. Multilevel modelling analyses were performed to evaluate the overall effect. Temporal effects were scrutinized by individual regression analyses and determination of the time to reach a minimal clinically important difference. Furthermore, individual graphs were visually inspected for potential patterns. Twenty patients with chronic low back pain and complex regional pain syndrome type I were included. On a group level, both fear and pain were reduced following EXP. Individually, fear was significantly reduced in 65% of the patients, while pain in only 20%. A decrease in fear was seen mostly in the first weeks, while pain levels reduced later or remained unchanged. Daily measurements provided rich data on temporal trajectories of reductions in fear and pain. Overall, reductions in fear preceded pain relief and seemed to be essential to achieve pain reductions.

Highlights

Chronic pain is characterized by a complex interaction between physical and psychosocial factors, and remains a therapeutic challenge [1]
The recruitment period resulted in 38 included patients in BrainEXPain, of which 23 initiated and completed Exposure in vivo (EXP)
The findings of this study are consistent with previous single-case experimental design (SCED) studies that concluded that EXP had a positive effect on fear and intensity in patients with CRPS-I [18] and cLBP [48]

Summary

Introduction

Chronic pain is characterized by a complex interaction between physical and psychosocial factors, and remains a therapeutic challenge [1]. Psychosocial factors have been recognised as important contributors to the development and maintenance of chronic pain and related disability. It is a beneficial protection mechanism to fear and avoid activities that are associated with pain and potential further damage. This behaviour becomes maladaptive when it persists into the chronic stage [3]. Avoidance of daily activities results in functional deterioration, contributes to more pain and increases the fear of (re)injury [4]. This vicious circle is described as the fear-avoidance model [2]

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Discussion

Conclusion