Graduation Semester and Year
Summer 2025
Language
English
Document Type
Thesis
Degree Name
Master of Science in Biomedical Engineering
Department
Bioengineering
First Advisor
Dr. Hanli Liu
Second Advisor
Dr. Kartavya Sharma
Third Advisor
Dr. Danilo Cardim
Abstract
Traumatic brain injury (TBI) is a major cause of neurological impairment, often leading to variable recovery and uncertain prognosis in the neurocritical care setting. There is a pressing clinical need for robust, physiologically grounded biomarkers to inform prognosis and therapeutic decision-making in acute TBI. This thesis investigates neurovascular coupling (NVC), the physiological coordination between neuronal activity and cerebral blood flow, as a candidate biomarker for brain function and recovery after injury.
A prospective cohort study was performed using simultaneous electroencephalography (EEG) and near-infrared spectroscopy (NIRS) recordings in patients with moderate-to-severe TBI and healthy controls. Wavelet transform coherence (WTC) analysis was used to quantify dynamic NVC, including coherence amplitude, phase relationships, and the fraction of significant coherence areas. Results revealed impaired neurovascular coupling in TBI patients compared to controls, as indicated by lower mean coherence amplitude (Rsq: 0.271 ± 0.038 vs. 0.300 ± 0.032), increased temporal phase variability, and reduced fraction of significant coherence (fracSig: 0.653 ± 0.081 vs. 0.708 ± 0.047).
These findings provide preliminary evidence that EEG-NIRS coherence analysis can serve as a bedside-accessible biomarker for NVC dysfunction in acute TBI. Such measures may ultimately contribute to improved monitoring, risk stratification, and individualized care in neurocritical settings, where rapid assessment of brain function is essential for guiding clinical management and recovery potential.
Keywords
Electroencephalography, Near-Infrared Spectroscopy, Neurovascular Coupling, Traumatic Brain Injury, Continuous Wavelet Transform, Neurovascular Unit, Continuous Wavelet Transform, Oxyhemoglobin, Squared Coherence Amplitude, Fraction of Significant Coherence
Disciplines
Bioelectrical and Neuroengineering | Biomedical | Biomedical Engineering and Bioengineering | Signal Processing
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Armstrong, Zachary, "Neurovascular Coupling Impairments in Acute Traumatic Brain Injury: An EEG-NIRS Analysis" (2025). Bioengineering Theses. 226.
https://mavmatrix.uta.edu/bioengineering_theses/226
Included in
Bioelectrical and Neuroengineering Commons, Biomedical Commons, Signal Processing Commons
Comments
I would like to express my deepest gratitude to my thesis advisor, Dr. Kartavya Sharma, whose mentorship, guidance, and support have been vital throughout this research. I am also grateful to Dr. Hanli Liu and Dr. Danilo Cardim for their insightful feedback and continuous encouragement, significantly enhancing the quality of this work.
Special thanks to the clinical and research teams for their collaboration in patient recruitment and data collection. Lastly, I am profoundly thankful for the support and encouragement from my family and friends, whose belief in my work has been of great motivation.