An algorithm that can accurately gauge heart rate by measuring tiny head movements in video data could ultimately help diagnose cardiac disease.
After developing mild cerebral edema from being strapped flat on his back in a spinning chair, space shuttle payload commander Richard M. Linnehan admitted that being a human guinea pig in space has its drawbacks.
Overall, Dr. Linnehan, keynote speaker at the Harvard-MIT Division of Health Sciences and Technology's (HST) annual forum last Thursday, was upbeat about his roles as an experiment operator and an experiment subject on the 1996 Life Sciences and Microgravity Spacelab mission and the 1998 Neurolab. Laurence R. Young, Apollo Program Professor of Aeronautics and chair of the panel discussion following Dr. Linnehan's talk, described Dr. Linnehan as "one of several highly trained scientists who served as the eyes and hands and brain" of researchers who designed the experiments to gauge the effects of weightlessness on humans and animals.
Professor Young is director of the new National Space Biomedical Research Institute, a consortium devoted to developing an understanding of and countermeasures to mitigate the effects of long-term space flight. Experiments such as those conducted by Dr. Linnehan will be critically important to the success of a future mission to Mars, which will take humans in zero gravity for unprecedented amounts of time, he said. The results also are relevant to earthbound populations.
To provide students an opportunity to present and discuss their work, HST established an annual scientific symposium in 1987 called the HST Forum. This year's forum included a student poster session in the atrium of Building E25, a plenary session at the Marriott Hotel, a reception and dinner.
Besides the experiment that spun the shuttle astronauts on their backs, Dr. Linnehan, a veterinarian, and his colleagues aboard the shuttle carried out experiments on rats who were so young when they boarded the shuttle that they spent most of their early lives in zero gravity. The baby rats learned how to grab onto bars to keep from free-floating in space, and like the astronauts, who moved around the cramped quarters with subtle, slow movements to keep from spinning out of control, they learned to get around primarily by moving only their front limbs.
There were experiments involving crickets and fish as well as sleep experiments on the human subjects, who slept in what Dr. Linnehan described as "casket-like" quarters that lined the sides of the orbiter. In an experiment designed by Dr. Charles M. Oman, senior research engineer in the Department of Aeronautics and Astronautics and director of the Man Vehicle Lab, the astronauts were forced to spin rapidly with their eyes open--not one of their favorite experiments, Dr. Linnehan reported.
Dr. Oman has long been interested in the connection between the human inner ear and balance. He said space sickness was such a major concern in early manned space flights that it put the Russian space program on hold for a year. Dr. Oman added that scientists have learned a lot since then about motion sickness in space, which also applies to motion sickness closer to home. It turns out, he said, that head movement and visual cues have a lot to do with the problem.
After the talk by Dr. Linnehan, a panel discussion chaired by Professor Young explored how the space shuttle experiments can help provide valuable knowledge in fields unrelated to space travel. For instance, panelist Charles A. Czeisler, professor of medicine at Harvard Medical School, described how his sleep research, which was carried out on missions STS-90 and STS-95, can help scientists understand how our internal clocks get "reset" as we grow older. Like aging people, astronauts tend to lose some sleep each night. The cumulative effect of this sleep loss could be as serious for earthbound individuals as for astronauts on Mars missions that last for months at a time.
Resetting an internal clock also is important to shift workers who need to sleep in the daytime and work at night.
Other panelists were Richard J. Cohen, the Whitaker Professor in Biomedical Engineering, and principal research scientist Gordana V. Vunjak-Novakovic, both of HST. Dr. Cohen is director of the NASA Center for Quantitative Cardiovascular Physiology, Modeling and Data Analysis, which he founded to improve the understanding of cardiovascular function and the effects of space flight on cardiovascular function. Dr. Vunjak-Novakovic is supervising research teams working on two NASA-funded projects: tissue engineering of musculoskeletal and cardiovascular tissues, and the scientific design and testing of the cell culture unit to be used aboard the International Space Station.
A version of this article appeared in the March 10, 1999 issue of MIT Tech Talk (Volume 43, Number 22).