Anna Kharko

ORCID

Abstract

Understanding pain is integral to understanding fibromyalgia, a chronic musculoskeletal pain condition of undetermined aetiology, and for which no single successful medical therapy exists. Most of what is known about fibromyalgia pain comes from psychophysical research of central sensitisation, a phenomenon of abnormally amplified pain following disruptions in the central nervous system. Anxiety has been long theorised to mediate this centralised pain, but its contribution is yet to be characterised. This thesis presents a multimodal investigation of pain perception under different manifestations of anxiety in both fibromyalgia-diagnosed and pain-free cohorts. Chapter 3 presented the findings from the first study in the series of PhD research, in which a novel method for gathering pain ratings was tested. Continuous pain report allowed for the extraction of novel measures, which characterised the unique properties of pain processing in fibromyalgia. Chapter 4 described a study with pain-free participants, in which, for the first time, continuous pain ratings were combined with concurrent modulation and report of experimentally maintained acute anxiety. Results indicated that anxiety evoked through the 7.5% CO2 Model is associated with an overall decrease of reported pain but not with individual measures, extracted from the pain response. Chapter 5 further adopted the successful pain and anxiety experimental paradigm and tested its feasibility with fibromyalgia-diagnosed participants. The limited success of the study discouraged further use of the CO2 Model with that patient population but highlighted the significance of anxiety for that condition. The final chapter, Chapter 6, explored the role of anxiety under a different taxonomy, as sustained psychological distress evoked by the COVID-19 pandemic. In an observational study, it was revealed that fluctuations in sustained anxiety are mirrored by changes in reported pain intensity. Together, the findings support that the study of anxiety advances the understanding of fibromyalgia pain processing, and argue for the continued research of both their momentary and long-term interaction for the comprehensive understanding of their relationship.

Keywords

fibromyalgia, acute pain, chronic pain, acute anxiety, 7.5% CO2, sustained anxiety, COVID-19

Document Type

Thesis

Publication Date

2021

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