Smart Prosthetics: Exploring Assistive Devices for the Body and Mind: Task Group Summaries (2007)

Haley Poland, Graduate Student

Annenberg School of Journalism, University of Southern California

Whether they are helping a blind person see, a deaf person hear, or a double amputee walk, prostheses have come a long way since Captain Hook. What were once wooden limbs and glass eyes are now engineered electromechanical devices interfacing with human body systems and communicating, almost intelligently, with the human nerves and brain. For thousands of people living with disabilities, “smart” prosthetics could mean faster rehabilitation, more effective therapy, and even return to an independent life. From joint replacements, cochlear devices, and brain implants to artificial valves, hearts, and limbs, advancements in prosthetic devices are beginning to blur the line between technology and biology.

From November 9 to 11, 2006, more than 150 researchers in fields ranging from biomedical and material engineering to surgery, neurology, and military medicine converged upon the Arnold and Mabel Beckman Center in Irvine, California. The fourth annual conference of the National Academies Keck Futures Initiative (NAKFI), “Smart Prosthetics: Exploring Assistive Devices for the Body and Mind,” challenged participants to determine just what “smart” means and how best to achieve that smartness in the future.

As smart prostheses are engineered structures designed to exist beside or within human physiology, the field is inherently interdisciplinary. The

novelty of an interdisciplinary conference breeds enthusiasm, excitement, and innovative thinking, but such a conference also requires a common level of understanding on a wide range of topics. As Hunter Peckham, chair of the NAKFI Smart Prosthetics Committee aptly stated, “We’ve grown up in scientific silos.” To bridge the gaps 13 overview tutorials presented the basics of the associated fields and the state of those fields in science today. For the first time since the NAKFI conferences began four years ago, the overview tutorials, intentionally broad to give the scientists familiarity with topics outside of their own expertise, were webcast live prior to the conference.

In one tutorial Robert Kirsch, associate professor of biomedical engineering at Case Western Reserve University, described and discussed systems for maintaining homeostasis—a balanced internal environment. He noted that a smart prosthesis should play the same homeostatic role in the body as whatever body part it’s replacing. Simply stated, motor controls go out from the brain to the device as sensory feedback comes in—a closed loop.

Warren Grill, associate professor of biomedical engineering, neurobiology, and surgery at Duke University, walked conference participants through the basics of neural stimulation, which feeds information into the nervous system, and neural recording, which interrogates the nervous system to determine the internal state and could also provide command signals to a prosthetic device. In discussing how to improve orthotics to help people walk, Bradford Bennett, research director of the Motion Analysis and Motor Performance Laboratory and assistant professor of research at the University of Virginia, promoted patient-specific models that record and adapt to a person’s individual gait.

Addressing a less technological but integral aspect of prosthesis development, Mark Humayan, professor of ophthalmology at the Keck School of Medicine, and Frances Richmond, director of the Regulatory Science program at the University of Southern California, outlined the rigorous regulatory process a medical device must go through on its path from benchtop to bedside. As Richmond emphasized, it’s important to think about these processes as materials, components, and clinical trial methods are chosen during development. “If we choose the wrong path,” she said, “we greatly delay and make more expensive our ability to get to a commercial market.”

Two particularly captivating talks given were not overview tutorials but rather personal accounts from researchers who are also users of smart

prosthetic devices. Alexander Rabchevsky, assistant professor of physiology at the Spinal Cord and Brain Injury Research Center at the University of Kentucky, lost use of his lower body due to a spinal cord injury in a motorcycle accident in the 1980s. In recounting his own trials with the surgically implanted functional electrical stimulation (FES) for standing, exercise, and transfers, Rabchevsky gave unparalleled insight into the life-changing impact prosthetic devices can have. After almost two decades lying down or in a wheelchair, the FES allows him to stand, if only for a few moments, and look his wife in the eye. Hugh Herr, associate professor of media arts and sciences at Massachusetts Institute of Technology, lost both legs below the knee to frostbite in a climbing accident when he was 17. A “better rock-climber with his specialized prostheses than he was before the accident,” Herr now builds cutting-edge limb devices that use technology to harness and even improve upon the abilities of the human body. For both Rabchevsky and Herr their firsthand knowledge of prosthesis use contributes immensely to their research—as it did to the NAKFI conference.

Whenever everyone gathered in the auditorium over the course of three days, the unique temperament of the conference emerged. Often, a witty and well-timed joke made the audience erupt in rollicking laughter. At other times, during discussion of provocative or controversial topics, the auditorium resembled British Parliament or the trading floor of the New York Stock Exchange. But whether the group was in agreement or dissent, the variety of perspectives and the passion behind them were undeniable.

While the plenary tutorials and a question-and-answer panel provided a foundation from which to build, the 11 task groups were where the heavy lifting occurred. Over the course of the conference each intentionally diverse group was given eight hours to address a challenge question or statement. With the deadline fast approaching, groups contemplated plans to restore sensory perception of limb movement, design a prosthesis to grow with a child, replace damaged brain tissue, and design a functional tissue prosthesis. Others tackled problems like electrode longevity, the best way for electrodes to interface with the brain, and how hybrid prostheses might exploit electrical processes within nerve cells.

The level of expertise in each group meant highly technical discussions, and during the first two-hour session, more than a few people were

looking at each other as if to say, “How is this ever going to come together?” In some rooms the groups were suspended by an uncomfortable tension as participants hesitantly hashed out where the discussion was headed and just who was going to head it. In other rooms effective collaboration created a synergy that had some enlivened scientists rocking in their chairs, like children who can’t sit still. Remarkably, at the end of eight hours every group had a plan.

On the last day, during more than four hours of task group “report-outs” in the auditorium, a spokesperson for each group outlined the plan of attack. While some had developed preliminary models of material devices or structures, others had generated elaborate analyses of the most pressing science and technology gaps related to the group’s challenge question. One group, asked to design a functional tissue prosthesis, diagrammed a renewable internal power supply for a prosthetic device. The hybrid-technology “battery pack” aimed to harness cellular energy by aligning electrocytes, coaxed to behave in a certain way, on an implantable, biocompatible platform. In troubleshooting the topic of brain electrodes, a group proposed tissue engineered, self-inserting bioelectrodes (which use neurons to interface with neurons), as well as optically based interfaces that make use of the photovoltaic properties of photosynthetic membranes. Another group asked, “Can brain control guide or refine limb control?” and started off their final presentation with a definitive answer: “Yes.” What followed was a research plan to develop a device that could identify, capture, and decode neural signals when a patient intends to move a limb that is not really there.

In reality, the task groups were not expected to solve the complex quandaries placed before them. The group sessions served to catalyze interactions between fields by allowing a diverse group of people to pursue novel patterns of thought, free of the logistical delays of actual research. It’s in this collaborative stumbling toward big ideas—in that faltering sense of direction—that the truly great strides take place. And, figuratively, that may mean going from Chicago to New York via Los Angeles. The value is in what was happened upon and who was met along the way.

The days were long, and conference goers, some admittedly drained of their day’s supply of scientific inspiration, happily relaxed and networked during the receptions and dinners. It was during these periods that an invaluable outcome of the conference became evident: Relationships formed across disciplines. “I definitely met people that I’ll be talking to very soon,” said one scientist on the last day. “The important stuff happens after the conference.”

For this reason the Futures Initiative offers an incentive for collaboration as part of its mission to promote innovative scientific investigation. Each year $1 million in seed grants, up to $75,000 each, are awarded competitively to conference participants wishing to pursue interdisciplinary research, learn new skills, or perhaps keep alive a fledgling dialogue begun at the conference. This year’s grants will be announced in April 2007.

While promoting interdisciplinary research sits at the top of the initiative’s priority list, not far below is effective communication of scientific ideas and advancements to the general public. To make science understandable for a wide audience, science journalists usually find themselves whittling daunting and dizzying topic areas into digestible bites of accessible language. Making scientific complexity simple takes concerted time, effort, and practice. What better opportunity to hone such a skill than at an interdisciplinary conference on a subject like smart prosthetics? Accordingly, NAKFI invited graduate science writing students from universities across the country to attend the conference. Each science writer participated in a task group, and then wrote an article documenting the group’s conclusions. The task group summaries are collected here to provide an overview of this integral part of the conference.

To further underscore the significance of effectively communicating science, the National Academies presented three $20,000 communications awards during dinner at the Beckman Center on November 9th. The communications awards acknowledge excellence in reporting and communicating science, engineering, and medicine to the general public. In the book category author Charles C. Mann received an award for 1491: New Revelations of the Americas Before Columbus, a debunking of popularly held notions of the pre-Columbian Americas. Elizabeth Kolbert of The New Yorker was acknowledged for her three-part series The Climate of Man, on the science and politics of global climate change. Last, director Nic Young, producer Anna Thompson, and executive producer Bill Locke received a 2006 Communication Award for the History Channel and Lion Television’s Ape to Man, a documentary overview of human evolution.

In the keynote address Michael Merzenich of the Keck Center for Integrative Neurosciences said, “We can make smarter prostheses when we’re smarter in integrating state-of-the-art neuroscience with state-of-the-art engineering, medical, and social science.” As was acknowledged during the conference, researchers cannot underestimate the capacity of the human brain—to restore function, to be trained, to make up for what’s been lost in extraordinary ways. If with the help of prosthetic devices sensory information can continue to flow into the brain from the peripheral nervous system, research shows that the brain will learn to use that information for motor control. Now isn’t it remarkable what a person (and a person’s brain) can do with a little help?