Publication Date


Document Type


Committee Members

Ulas Sunar, Ph.D. (Advisor); Brandon Foreman, M.D., FACNS (Committee Member); Tarun Goswami, Ph.D. (Committee Member)

Degree Name

Master of Science in Biomedical Engineering (MSBME)


There is a need to improve methods of monitoring patients with traumatic brain injury (TBI) in hospital settings. Current monitoring techniques and diagnosis methods are expensive, invasive, do not provide continuous measures, expose the patient to radiation, are ambiguous in the information they provide, and/or cannot be implemented at the bedside. These techniques measure imperative markers of brain function including intracranial pressure (ICP), cerebral blood flow (CBF), and oxygenation in the brain, among others. Hospitals not only require a practical method for real-time monitoring of patients at the bedside, but also meaningful metrics that characterize TBIs, since the variety of methods results in complex and ambiguous criteria for defining TBIs. Trends in the literature show a reliance on functional assessments such as the Glasgow Coma Scale (GCS) to define TBIs, however studies have shown its complexity and context-dependence in predicting outcome. Real-time cerebral assessment is currently focused on ICP monitoring, but increased attention to hemodynamic measures to improve patient outcomes warrants new technologies and metrics. Therefore, in this thesis, a novel metric of low-frequency oscillations (LFOs) from hemodynamic monitoring is proposed to provide a more objective characterization of TBI. Literature suggests that these LFOs originate from the regulation of regional changes in CBF and energetic metabolism and not from systemic regulation of the cardiovascular system, making it a representative metric of brain function. Overall, this thesis will contribute to the clinical understanding of TBI through optical imaging-derived LFOs. To achieve this overall goal, the followings have been investigated between non-TBI and TBI groups: 1) quantification of absolute concentration changes of hemodynamic parameters, 2) assessment of the LFO spectrums of the oxygenated hemoglobin signals to identify prevalent LFOs, and finally 3) quantification of the average power in predefined LFO slow bands. The results indicate that optical imaging can provide noninvasive neurovascular biomarkers for continuous assessment of TBI patients.

Page Count


Department or Program

Department of Biomedical, Industrial & Human Factors Engineering

Year Degree Awarded