Dissertation
Monitoring and analysis of hemodynamic response to cold noxious stimuli using functional near infrared spectroscopy
Doctor of Philosophy (Ph.D.), Drexel University
Jul 2013
DOI:
https://doi.org/10.17918/etd-7000
Abstract
The gold standard for evaluating the presence, intensity, quality and location of pain is self-reporting questionnaires, if communication is not impaired. These questionnaires are highly subjective. Thus, there remains an unmet clinical need for a practical, inexpensive tool for the reliable and objective assessment of human response to pain. Due to inherent interaction between the autonomic nervous system (ANS) and the central pain processing system, we attempted to indirectly assess the intensity of ongoing pain by measuring the ANS response to painful stimuli using functional near infrared spectroscopy (fNIRS). fNIRS can be used for noninvasive, continuous monitoring of the hemodynamic activity on the cortex as well as skin. The objective of this PhD research is to investigate the feasibility of employing fNIRS technology for objective assessment of pain in human through the hemodynamic parameters measured by fNIRS at the skin and cortex in response to noxious stimuli. We used cold pressor test (CPT) as an experimental model of chronic pain. We used three consecutive 45-min trials of a CPT. We identified a parameter from fNIRS signal that significantly correlated with subjective pain scores. In another experiment, subjects immersed their hand into cold water of varying temperatures for as long as they could tolerate the cold pain/unpleasantness. Using multi-distance probes, we observed an asymmetrical activity in the prefrontal cortex and no laterality in the skin response. This finding suggests that while the generalized autonomic response is global, there is a hemispheric asymmetry in the prefrontal cortex during cold water stimulation. Moreover, we observed sex-specific cortical activation which suggests sex differences in central processing/regulating of nociceptive information. In this research, we showed that a cold painful stimulus evokes a reproducible and consistent hemodynamic response which can be reliably detected by fNIRS as a non-invasive, portable device. We found an association between the noxious stimulus and the evoked hemodynamic response. Further refinement of the proposed method, including incorporating advanced signal processing techniques and employing other noxious stimuli, in order to extract pure cortical response is required to make the fNIRS technique a powerful clinical tool for pain assessment.
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Details
- Title
- Monitoring and analysis of hemodynamic response to cold noxious stimuli using functional near infrared spectroscopy
- Creators
- Zeinab Barati - DU
- Contributors
- Kambiz Pourrezaei (Advisor) - Drexel University (1970-)Issa Zakeri (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xiv, 123 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- School of Biomedical Engineering, Science, and Health Systems (1997-2026); Drexel University
- Other Identifier
- 7000; 991014632180304721