Central sensitization in chronic pain and medically unexplained symptom research: A systematic review of definitions, operationalizations and measurement instruments

Carine den Boer; Linne Dries; Berend Terluin; Johannes C van der Wouden; Annette H Blankenstein; C Paul van Wilgen; Peter Lucassen; Henriëtte E van der Horst

doi:10.1016/j.jpsychores.2018.12.010

Central sensitization in chronic pain and medically unexplained symptom research: A systematic review of definitions, operationalizations and measurement instruments

J Psychosom Res. 2019 Feb:117:32-40. doi: 10.1016/j.jpsychores.2018.12.010. Epub 2018 Dec 25.

Authors

Carine den Boer¹, Linne Dries², Berend Terluin², Johannes C van der Wouden², Annette H Blankenstein², C Paul van Wilgen³, Peter Lucassen⁴, Henriëtte E van der Horst²

Affiliations

¹ Amsterdam UMC, Vrije Universiteit Amsterdam, Department of general practice and elderly care medicine, Amsterdam Public Health research institute, the Netherlands. Electronic address: c.denboer@vumc.nl.
² Amsterdam UMC, Vrije Universiteit Amsterdam, Department of general practice and elderly care medicine, Amsterdam Public Health research institute, the Netherlands.
³ Transcare, transdisciplinary pain management centre, Groningen, the Netherlands; Pain in Motion International Research Group, Department of Physiotherapy, Physiology and Anatomy, Vrije Universiteit Brussel, Brussels, Belgium.
⁴ Radboud University Medical Center, Radboud Institute for Health Sciences, Department of Primary and Community care, Nijmegen, the Netherlands.

PMID: 30665594
DOI: 10.1016/j.jpsychores.2018.12.010

Abstract

Objective: Central sensitization (CS), a mechanism explaining the persistence of symptoms, has been the focus of many research projects. Explanations given to patients with chronic pain are often based on this mechanism. It is hypothesized that CS also plays an important role in the persistence of medically unexplained symptoms (MUS). However, definitions and operationalizations of CS vary. We conducted a systematic review of definitions, operationalizations and measurement instruments of CS.

Methods: We searched in PubMed, EMBASE, PsycINFO, Cinahl and The Cochrane Library till September 2017 and included papers that addressed CS in relation to chronic pain and/or MUS. Two reviewers independently selected, analysed and classified information from the selected publications. We performed a thematic analysis of definitions and operationalizations. We listed the measurement instruments.

Results: We included 126 publications, 79 publications concerned chronic pain, 47 publications concerned MUS. Definitions of CS consistently encompass the theme hyperexcitability of the central nervous system (CNS). Additional themes are variably present: CNS locations, nature of sensory input, reduced inhibition and activation and modulation of the NDMA receptor. Hyperalgesia and allodynia are widely mentioned as operationalizations of CS. Quantitative sensory testing (QST) and (f)MRI are the most reported measurement instruments.

Conclusions: There is consensus that hyperexcitability is the central mechanism of CS. Operationalizations are based on this mechanism and additional components. There are many measurement instruments available, whose clinical value has still to be determined. There were no systematic differences in definitions and operationalizations between the publications addressing MUS and those addressing chronic pain.

Keywords: Central sensitivity syndrome; Central sensitization; Chronic pain; Definition; Measurement instruments; Medically unexplained symptoms; Operationalization.

Publication types

Systematic Review

MeSH terms

Central Nervous System Sensitization / genetics*
Chronic Pain / diagnosis*
Chronic Pain / pathology
Female
Humans
Male
Medically Unexplained Symptoms*
Research Design