Biomedical Engineering Faculty Dawnlee (Dawn) Roberson, Ph.D. Assistant Professor Department of Biomedical Engineering Educational Background: M.S.E.E., University of Texas at San Antonio Ph.D., University of Texas at Austin Postdoctoral, Rehabilitation Institute of Chicago Areas of Research Interest: My research interests and projects fall into two main areas: Electrophysical and biological signal processing and Biomechanics. I had a development grant, sponsored by the NSF, to extend her studies in electrophysiology and expand my expertise into biomechanics. I have studied nonlinear signal processing and apply those techniques to a variety of biomedical signals, specifically in muscle control. I am developing expertise in motion analysis while studying prothesis use in amputees and shoulders in manual wheelchair users. Decomposition of Biological Signals One line of research focuses on the relationship between the descending nerve control signal to a muscle (the electroneurogram - ENG), the muscle signal (the surface electromyogram - EMG) and the force generated by that muscle. Elucidation of an index of activation between these three signals would be used for many things, such as control of a prosthetic device. Development of this index is proceeding in many research laboratories across the country, but is hindered by these two factors: 1) complex data collection and 2) use of linear analysis techniques applied to inherently nonlinear systems. I have developed an experimental protocol to capture these natural signals and have designed a basis function using wavelets that can be used to decompose these signals into their components. I and my lab team are finetuning the data collection and decomposition technique. Gait/Motion Analysis Bipedal gait (walking on two legs) is one of the most complex tasks to master. The seemingly effortless process of swinging one leg forward after another is really a complex interaction of the brain and many muscles. The mechanics of gait are very often modeled as an inverted pendulum. The majority of the normal human body mass (over 2/3) is located above the (hip) joints about which we balance. This system requires active control to keep balanced during quiet stance. While walking, one foot is on the ground, instead of the two during quiet stance, so the control dynamics are more active, in both the medial-lateral (side to side) and anterior-posterior (front to back) directions. Gait analysis data can be divided into three categories: kinematics, kinetics and electromyography (EMG). Kinematics is the calculation of joint positions during gait. By using infrared cameras and taping reflective markers to the skin, joint angles in all three movement planes can be determined at every point in a gait cycle. Kinetics is the combination of kinematics with force in during gait. By using infrared cameras and taping reflective markers to the skin, joint angles in all three movement planes can be determined at every point in a gait cycle. Kinetics is the combination of kinematics with force information. With the use of forceplates in the floor, some information can be obtained about the forces produced by the muscles during gait. EMG provides information about muscle activation timing as the patient walks. I am an investigator with the Gait Analysis and Innovative Technology (GAIT) Laboratory at the University of Texas Health Science Center at San Antonio which has an 8-camera VICON system, 4 AMTI force plates, and a 16 channel EMG system for motion analysis. Current research studies include prosthetic foot guideline develoment, shoulder health for manual wheelchair users, spine motion, and diabetes. I am active in the local IEEE Chapter, serving as the email newsletter editor, and am the Program Chair for the local Engineering in Medicine and Biology Society. I am also active in the local Women in Engineering section, and am the Faculty Mentor for the UTSA Society of Women Engineers. Selected Publications: H Lee and D Roberson, "Systemic View of Upper Extremity Prosthsis," Presented at the IEEE Intl Conference of Systems of Systems, San Antonio, TX, April 2007. R Trevino, G Walden and D Roberson, "Delay in Response Time by the Right or Left Leg When Other Body Muscles are Stimulated", Proceedings of the Annual Biomedical Research Conference for Minority Students, Anaheim, CA, 2006. D Roberson and F Hudson, "Biomechanics as a tool for teaching minority students", Presented at the 113th Annual Conference for the American Society for Engineering Education, Chicago IL, June 18-21, 2006. DJ Roberson, WE Rogers, GW Bosker, JG Walden and NE Walsh, "Prosthetic Foot Guideline Development: A Multi-domain study of older, dysvascular transtibial amputees Effect of prosthetic Foot Type on plantar pressure and cadence", Invited submission for the Houston Society of Engineering and Medicine, 9-10 February, 2006. D Roberson, B Rogers, G Bosker, G Walden and N Walsh, "Prosthetic Food Guideline Development: Center of Force and Cadence Variations in Self-Selected Walking Speed," Archives of Physical Medicine and Rehabilitation, 85:9 pE46, September 2004. DJ Roberson, CF Phelix, and CB Schrader, "A natural muscle recruitment preparation," presented at the Conference for Neuroscience, 2003. D Holland, D Roberson and W Barfield, "Applications of Computing on and under the Skin", in Fundamentals of Wearable Computers and Augmented Reality, Lawrence Erlbaum Associates, New Jersey, 2001 D Roberson, WZ Rymer, "Decomposition of low force, simulated EMG using wavelets," Proceedings of the 21st Annual International Conference of the IEEE Engineering in Medicine and Biology Society, p 576, September 1999. D Roberson, R Barr, CB Schrader and RJ Thornhill, "Experimental Correlation of the Electroneurogram, the Surface Electromyogram, and the Generated Muscle Force," Proceedings of the 3rd International Workshop on Biosignal Interpretation, pp. 166-169, May 1999. C Schrader and D Roberson, "Muscle Control Using Proportional Detection of Electromyographic Signals", Proceedings of the 33rdIEEE Conference on Decision and Control, pp. 2932–2933, December 1994. D Roberson, M Fernjallah, R Barr and R Gonzalez, "Preconditioning Electromyographic Data for an Upper Extremity Model Using Neural Networks", Proceedings of the 1994 IEEE International Conference on Systems, Man and Cybernetics, pp. 969 –974, October 1994. Contact Information: College of Engineering, Room BSE 1.334 Department of Biomedical Engineering University of Texas at San Antonio Phone: 210-458-5520 Fax: 210-458-7007 Dawnlee.Roberson@utsa.edu Return to faculty page   Return to top of page