Biological Systems Engineering, Department of


Date of this Version

Fall 11-30-2012

Document Type



A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Agricultural and Biological Systems Engineering, Under the Supervision of Professor Gregory Bashford. Lincoln, Nebraska: December, 2012

Copyright (c) 2012 Brian P. Watt


Examining physiologic responses of cerebral blood flow (CBF) for subjects in challenging situations requires development of new technology. Challenging circumstances include strenuous physical activity, intensive care, and surgical procedures involving the head, neck and thorax. Headset technology to employ transcranial Doppler (TCD), which is commercially available, fails to meet several requirements for monitoring in these situations. These requirements include stable signal acquisition, non-interference with other physiological monitors, ability to fit all head sizes including infants and children. The design and development of a novel TCD headset was performed to meet these requirements. The new device theoretically allows the user to use TCD to challenging situations (e.g. cardiac surgery, pediatric use, exercise study, and concussion study). The fixation described is intended to improve the quality of care and better inform physicians, research professionals, and clinicians on CBF parameters during long-term monitoring.

To test feasibility of the design, the prototype of this fixation device was tested in two populations: 1) healthy individuals and 2) stroke affected participants. Both populations were engaged in exercise, cognitive, and dual task challenges in order to ascertain the ability of the new headset to provide stable signal acquisition. Monitoring was successfully conducted while subjects were engaged in these tasks for a period of more than 20 minutes.

This novel TCD fixation system is currently being used in several ongoing investigations focused on determining changes in CBF in subjects recovering from stroke and concussion. Further work is also planned to examine alterations in CBF in children and neonates who are undergoing corrective and palliative surgery for congenital heart disease.

Adviser: Gregory R. Bashford