New Dimensions in Designing Medical Devices

4:00PM Teaching Engineering Design
Clive L. Dym, Phd, PE, Fletcher Jones Professor of Engineering Design and Director of the Center for Design Education, Harvey Mudd College, clive_dym@hmc.edu
Moderator: William Wiesmann, MD, Founder, Chairman and Chief Executive Officer, BioSTAR Group, ww@biostargroup.com

According to Herb Simon, “design is the central activity of engineering.” At most engineering schools today, science-based analysis and reductionism are taught well; but the teaching of design, which requires questioning and synthesis, is sometimes neglected. Unlike being a good theoretician, being a good designer requires dealing with uncertainty and ambiguity. Engineers in the real world must understand how the parts of a system interact, and they must be good estimators, capable of using both empirical and experimental knowledge in their decision-making. Students of engineering must also realize that design is a social process requiring negotiation and the ability to balance conflicting objectives. Mathematical knowledge alone is necessary but not sufficient.

At Harvey Mudd College, design is a critical component of the general engineering curriculum, and courses are meant to ensure that students experience team-oriented, client-driven design projects. Freshmen take a single-semester design course that consists of a project created by the professor and a project suggested by a not-for-profit company. The students work in teams, and the teams are shuffled between projects. Upperclassmen participate in a three-semester design course in which teams of students complete projects for external clients. The projects are varied and range from childproofing fuel cells to building mountings for rocket boosters. The client company pays for the project, provides a liaison to the students, and owns the rights to any intellectual property that emerges from the project. One third to one half of the projects result in patents being filed. The experience of working with a team designing a product for a company gives the engineering students at Harvey Mudd a valuable glimpse of what it is like to work as a professional engineer.

View this presentation:
Bill Wiesmann
Clive Dym

4:30PM Medical Device Case Study: Ambulatory Vestibular Monitoring
Steven D. Rauch, MD, Associate Professor of Otology and Laryngology, Harvard Medical School, Massachusetts Eye and Ear Infirmary; Director, MEEI Balance Center, steven_rauch@meei.harvard.edu
Moderator: Alexander H. Slocum, PhD, Pappalardo Professor of Mechanical Engineering, MacVicar Faculty Fellow, Massachusetts Institute of Technology, slocum@mit.edu

Over 90 million U.S. citizens have experienced dizziness and balance problems, and it is estimated that 40 percent of the U.S. population will seek medical care for dizziness at some point. Nine percent of Americans experience chronic balance problems, and the cost of treating patients with balance problems and balance-related injuries is measured in billions of dollars. As the U.S. population ages, the need to treat balance problems will only become worse.

The balance, or vestibular, system consists of inputs, a central processing module, and outputs. The inputs include sensory information from organs in the inner ear, from the visual system, and from nerves associated with touch and proprioreception. These inputs are processed in the brain, and finally, the brain sends signals to the limbs and to the eyes, telling them how to adjust to motion. These adjustments are some of the body’s fastest reflexes.

It is difficult to directly study the central processing that occurs in the brain, but doctors can learn a lot about problems in the vestibular system by measuring the motion of a person’s eyes. When a person becomes dizzy, he or she usually experiences nystagmus, or rapid motion of the eyes. Currently, vestibulo-ocular reflexes can only be measured in a specially equipped laboratory. Unfortunately, the laboratory setting is unnatural, the tests are time-consuming, and the people being tested are often asymptomatic while in the lab.

An ambulatory vestibular monitoring (AVM) system capable of tracking eye movement outside the laboratory would be very useful to clinicians. Such a system would enable doctors to test patients anywhere, and it would provide valuable diagnostic information obtained in a natural environment. The device could conceivably correlate eye movement data with other types of information, such as a person’s electrocardiogram (ECG) waves and respiration rate. Steven Rauch and collaborators developed an AVM prototype, and they found that they were able to track eye movement with very little noise. Their device is in an early stage of development, however, and many improvements, from wireless electrodes to detectors of head motion, will hopefully be made in the future. It will take a lot of effort to bring the device to market, but the demand for the device might be very great.

View this presentation

View panel discussion