Source reconstruction of the neural correlates of ongoing pain using magnetoencephalography

Graeme-Drury, Thomas J (2023) Source reconstruction of the neural correlates of ongoing pain using magnetoencephalography. Doctoral thesis, Birmingham City University.

Thomas Graeme-Drury PhD Thesis published_Final version_Submitted Aug 2022_Final Award May 2023.pdf - Accepted Version

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Pain is a pervasive, complex, and subjective phenomenon that can be described by many features and researched using many paradigms; chronic pain has a significant impact on the quality of life of patients experiencing it and constitutes a large burden on the National Health Service. Discovering neural biomarkers for ongoing pain and pain sensitivity has the potential to elucidate underlying mechanisms, evaluate therapy effectiveness, and identify regions of interest within the brain for further study or intervention; something that is possible with functional imaging of brain activity. Magnetoencephalography (MEG) is a non-invasive technique that records brain activity through magnetic fields unobstructed by tissue of the head. This thesis utilises modern source reconstruction of MEG data to explore brain activity that characterises tonic pain conditions, and explores the future of tonic pain research by evaluating the utility of the PATHWAY Contact Heat Evoked Potentials Stimulator (CHEPS) – a tool used both as an experimental pain stimulus, and a clinical evaluation method in chronic pain – in current and future MEG research.

A systematic review of studies exploring the CHEPS and MEG, which highlights the paucity of the literature combining the two despite the potential benefits of each, is presented within.

Study one investigates the brain activity changes resulting from paraesthesia-based Spinal Cord Stimulation for chronic pain: significant enhancements in synchrony for theta and delta frequency bands during SCS-on resting-state are demonstrated, and a significant reduction in Somatosensory Evoked Potential (SSEP) power spectra in the SCS-on condition – providing evidence that conventional SCS influences resting and ascending processing in the brain, but does not necessarily suppress the field strength of SSEPs. Study two compared the neural activity of participants with high and low pain sensitivity during the Cold Pressor Test, and identifies regions of interest for future study. Study three is a methodological chapter which attempts to mitigate the methodological challenges involved in utilising the PATHWAY CHEPS in MEG research: The thorough exploration of independent component analysis, signal space separation and beamforming parameters demonstrates that it is possible to suppress the artefacts generated by the non-fMRI compatible CHEPS’ thermode with the application of signal attenuation techniques, but only in an empty room dataset; the implications of this for future research are discussed.

Item Type: Thesis (Doctoral)
5 August 2022Submitted
12 May 2023Accepted
Uncontrolled Keywords: Magnetoencephalography, MEG, pain, beamforming, cold pressor test, spinal cord stimulation, contact heat evoked potential stimulator
Subjects: CAH02 - subjects allied to medicine > CAH02-06 - allied health > CAH02-06-01 - health sciences (non-specific)
Divisions: Doctoral Research College > Doctoral Theses Collection
Faculty of Health, Education and Life Sciences > School of Health Sciences
Depositing User: Jaycie Carter
Date Deposited: 20 Jul 2023 10:33
Last Modified: 20 Jul 2023 10:33

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