Wireless Sensor Networks

INTRODUCTION How can we deliver quality care to a rapidly growing population of older adults - historically the most expensive demographic to treat - while reducing the nation's healthcare costs? We believe the solution must include three components: an emphasis on prevention rather than treatment; a shift in the focus of care from expensive clinical settings to the home; and a shift of some responsibility for care from formal providers to individuals and their family and friends. This solution can be enabled by a range of proactive computing technologies in the digital home. These digital home technologies have the potential to improve public health and significantly lower the healthcare bill while enabling seniors to "age in place," maintaining their independence and deferring more costly institutional care as long as possible. And it will be quite a generation. The worldwide population of those over 65 is predicted to reach 761 million by 2025, more than double what it was in 1990. Assuming current trends continue, this century will see the first time in human history that the old outnumber the young. Meeting the needs of those with the chronic diseases of aging— heart disease, Alzheimer's, and so forth—is a labor-intensive chore we increasingly cannot afford. Health care consumes 15 percent of the U.S. gross national product, up from 5 percent in 1960. In Japan and Europe, which manage care more frugally, the share has in most cases already passed the 10 percent mark. And the numbers continue to rise. We will have to find clever ways to economize on labor, the most expensive element in health care Improving Care, Reducing Cost World countries has the potential to improve the quality of care for its aging population while saving billions of dollars annually in healthcare costs, through home-based technologies that focus on prevention and early detection of health problems; improved

compliance with care plans; monitoring of older adults in their homes, and emergency response in the event of a fall or other health crisis. Together, these technologies could enable seniors to age in place in their home environment¹, maintain their independence, and defer more costly care in emergency rooms and institutional settings for as long as possible. Intel is investing in the digital home, proactive computing and other enabling technologies to help translate this vision into reality. Manufacturers of pacemakers are already beaming out data from the devices in the hope of picking up early trouble signs, so as to keep people out of the hospital. Meanwhile, electronics giants are working to pepper the home with a network of wirelessly linked sensors slapped on nearly everything from coffee cups to bathroom doors. They are learning to probe the network remotely to monitor patients with dementia and other ills of aging and use the information to help the patients' families care for them. The next generation of older people may live in a world where every beat of their hearts and every ordinary thing they do is watched, analyzed, and evaluated for signs of trouble. Orwellian as it may seem, such care may actually be less intrusive than the alternative: the loss of independence that follows when people must leave their own homes for nursing homes. Improving Life and Industry with Wireless Sensors The key is wireless sensor networks, an intriguing new technology model in which behavioral and biological data is collected and analyzed for customized proactive computing applications. As the name implies, proactive computing aims to anticipate people's needs and take action to meet those needs on their behalf, relieving people of tedious data entry. Intel has taken the initiative to invest in research and development of sensor networks, recognizing this technology as crucial to addressing the pending global age wave and public health crisis. Experts predict that the worldwide elderly population will grow dramatically as the post-World War II baby boom generation reaches retirement age. In the United States alone, the cost of caring for older adults is expected to escalate sharply in 2010, when 76 million baby boomers begin to reach age 65¹. Cognitive

and physical decline are also concerns. The Alzheimer's Association, for example, reports that more than 4 million Americans have the disease - a number that's projected to triple to 14 million by 2050 as the elderly population continues to increase. Sensor networks hold promise for meeting these challenges because they have the potential to revolutionize healthcare, but Intel also sees the technology as having broad application in virtually all aspects of life and industry. Intel envisions a proactive computing world in which a multitude of unseen, connected computing nodes automatically acquire and act on real-time data about a physical environment, helping to improve lives, promoting a better understanding of the world and enabling people to become more productive. Prevention of disease comes from unglamorous things like encouraging people to eat properly and to exercise, changes in habit that are famously hard to effect. The single best aid to such behavior modification is a support group, and there is some evidence that such groups can be bound more tightly together with technology. Using wireless sensors to track the routine activities of daily life— how people dress, what they cook in the morning, how well they drive their cars—might make for a mundane set of data. But such data can greatly help in the diagnosis of neurological disorders such as Parkinson's or Alzheimer's disease. Parkinson's can so far be diagnosed only through behavioral changes, principally changes in gait. Wireless networks can also bring a measure of independence to the lives of people suffering from cognitive decline Proactive Computing Applications for the Aging Many companies are exploring a variety of proactive computing applications that could assist the aging in the digital home environment. As the name suggests, proactive computing is designed to anticipate people’s needs and take action to meet the needs on their behalf. The input for proactive computing applications is real-world data gathered by wireless sensors. Intel

Research Berkeley is developing tiny sensors or "motes" which can be used to gather both behavioral and biological data for customized proactive health applications. Researchers at Intel Research Seattle and the University of Washington have built a prototype that can infer a person's activities of daily living (ADLs). By placing sensor tags on everyday objects such as a toothbrush or coffee cup and using tag readers to track the movement of tags, we can determine, for example, whether a person has brushed his teeth or taken medication. The long-range goal is to develop computerized assistants to help seniors and their caregivers manage ADLs so that seniors' independence is compromised as little as possible. Through the Intel Research Council, which funds university research worldwide, Intel is supporting dozens of researchers who are testing new home health and aging-in-place technologies. For example, one prototype system analyzes sensor data from drawers, medicine cabinets, pill bottles - wherever medications are stored - and delivers timely reminders via cell phone, TV, or whatever device is preferred or nearby. Two other projects: wearable wireless sensor networks that could alert caregivers to a senior's fall, and sensors in footwear which could monitor a person's gait for irregularity and prevent a crippling fall (and a costly hospital stay or premature move to a care facility). Such proactive intelligent systems could reduce healthcare costs by billions of dollars annually. Using wireless sensors to track the routine activities of daily life— how people dress, what they cook in the morning, how well they drive their cars—might make for a mundane set of data. But such data can greatly help in the diagnosis of neurological disorders such as Parkinson's or Alzheimer's disease. Parkinson's can so far be diagnosed only through behavioral changes, principally changes in gait. Yet to get a really early diagnosis would require noticing quite subtle distinctions Sensor networks are powerful new tools that can assist with care giving across the continuum of care. They could be used to monitor the safety of an older adult in the home, allowing a family caregiver to take a nap or a break and ultimately, prevent burnout. The digital home network could be accessed through the Internet, enabling adult children to check in remotely to assess the well-

being of an aging parent far away. Wireless sensors and mobile computing devices in skilled nursing facilities could automatically capture diagnostic and behavioral data, thus freeing an overburdened nursing staff to spend more quality time with residents, reducing data entry errors, and providing real-time feedback to facility managers about the health of their residents, staff, and their overall facility. Variety of technologies in the digital home will enable older adults to age in place, improving the quality of their lives and reducing healthcare costs by deferring expensive institutional care. Existing telemedicine technologies can access data from the digital home network, enabling virtual exams in the home. Proactive computing technologies under research at Intel and elsewhere will reduce costs further by enabling the aging to be proactive about caring for themselves. A network of sensors throughout the digital home will track and monitor health status and activities of older adults, providing input for proactive applications that will offer a variety of assistance, from reminders to take medications to help in completing cooking tasks and accessing social support. Seniors will access the network using a variety of familiar interfaces, such as telephones and televisions; they will not need to learn new technology to receive assistance. Such proactive systems will also enable adult children to assess the health and well-being of their aging parents remotely through private, secure Internet connections and will provide on-site caregivers with the social support they need to avoid burnout—a common problem among caregivers of older adults.

Inside Sensor Network Technology Wireless sensor networks represent an entirely new way of looking at computing. In a sensor network, dozens, hundreds or even thousands of tiny, battery-powered computers, often called "motes," are scattered throughout a physical environment. Silently and wirelessly, each mote in this ad hoc network collects data, for instance, monitoring light, temperature, humidity, vibration or other environmental factors. The mote relays the collected data to its neighboring motes and then to a specified destination where it is processed. This sensory input, when gathered from all the motes and analyzed by more traditional computers, paints a comprehensive, high-resolution picture of the surroundings in real time. What's in a mote? Essentially, the ability to sense, compute and communicate. Despite their complex functionality, motes have just three key hardware components: microprocessors, tiny microelectromechanical systems (MEMS) and low-power radios (also called transceivers). The microprocessors process the data, the MEMS sensors provide a broad array of sensory inputs, and the radios enable the motes to wirelessly transmit their sensor readings throughout the network. The next-generation Intel Mote hardware is a modular, stackable design that includes the following components in a package that is about half the size of the original Berkeley mote. Intel Research is using the Zeevo* module on the main board (containing an ARM1 core, SRAM and Flash memory, and Bluetooth* wireless technology), an optional power supply regulator, and sensor boards. The mote platform can accommodate other features as well, such as alternate radio, debug and actuator boards. A backbone interconnect provides power and bidirectional signaling capability.

Intel Mote software is based on Tiny OS, a component-based operating system designed for deeply embedded systems that require concurrency-intensive operations and which have minimal hardware resources. The software stack includes an Intel Mote-specific layer with Bluetooth* support and platform device drivers, as well as a network layer for topology establishment and single / multi-hop routing. The software will also incorporates security features, including authentication and encryption in the near future.

New software enables the raw data collected by the sensors to be analyzed in various ways before it leaves the network, ensuring a proactive stream of information that can be acted upon in real time. Standard consumer AA or coin-style batteries keep motes "alive" for six months to a year, and researchers are exploring other sources of power to further shrink size and extend longevity. Although the size, type and configuration of motes in a sensor network depend largely on the application, common design constraints include power conservation, compact form factor and limited memory and storage capacity. Moreover, motes must be reasonably economical to be suitable for practical applications. Fortunately, microprocessors, sensors and RF transceivers can be inexpensively produced in large quantities using conventional semiconductor manufacturing techniques The combination of small size, low cost and wireless networking functionality makes sensor network technology exceptionally scalable. As price points become more attractive, scientists will be able to deploy many sensors simultaneously, with better proximity to the physical phenomena being monitored and more detailed tracking than has heretofore been possible, leading to ubiquitous computing.

The Body Itself now plays host to some sensors. By the end of this month, Medtronic Inc., in Minneapolis, expects to gain approval to market in the United States a device designed to alleviate the symptoms of heart failure and warn, through a short-range wireless link to the Internet, of a patient's declining condition. About 22 million people worldwide suffer from heart failure, a condition in which the heart beats so weakly or inefficiently that fluid begins to pool in the lungs. This is the most rapidly growing cardiovascular condition in the world, and about half of all patients die within five years. Heart failure is the single greatest cause of hospitalization in the United States, costing some $10 billion a year in direct expenses. You have to get even closer, with body-borne sensors. Since August 2002, doctors in parts of the United States have been taking advantage of a system built by Cardio Net Inc., in San Diego, to discover the presence and nature of their patients' heart problems. Some serious heart problems affecting older people are transient and infrequent and can go unnoticed even by the patient. A sudden slowing of the heart rate that leads to a fainting spell, for example, may last less than a minute and occur only once or twice a week. That's often enough to make driving a car dangerous but not frequent enough for a doctor to spot during a checkup or even by using a portable 24-hour electrocardiogram (ECG) recorder, called a Holter monitor. Another problem, the uncoordinated quivering of the small upper chambers of the heart, a leading cause of stroke in people over 70, can be both infrequent and without obvious symptoms. So patient-triggered ECG recorders could miss it. Called mobile cardiac outpatient telemetry, Cardio Net’s system consists of a small three-lead ECG monitor, worn either as a pendant around the neck or on a belt clip, and a PDA-like device [see Illustration, A Networked Heart]. The ECG monitor sends its data via a 900-

megahertz wireless link to the PDA, which evaluates and stores the waveform. If software in the PDA notices a potentially harmful change, say, a sudden slowing of the heartbeat, it automatically transmits the relevant data over a cellular network to a monitoring center, which is staffed around the clock. Computers there, after making a preliminary judgment of the severity of the problem, determine where to put the event in a queue for the center's clinical staff to review. If the staff decides the event is routine, the data is just included in a daily report to the patient's physician. If the event is judged serious, the center alerts the physician and calls the patient with instructions to proceed to a hospital. Patients typically wear the device for no more than 10 to 14 days, after which the physician has enough data to figure out what the real problem is, The new heart failure device will be compatible with a two-year-old system Medtronic set up in the United States, called the CareLink Network, that lets doctors keep tabs on patients by taking data from pacemakers and other devices implanted in their chests [again, see A Networked Heart]. The patient puts an antenna over his chest to pick up data on fluid buildup, electrocardiogram and other physiological data, and data on the functioning of the pacemaker; the antenna then transmits the information over a phone line to a secure Internet site, accessible only to the patient's doctor. In early studies the device was able to detect the signs of a dangerous fluid buildup 10 or 11 days before the patient noticed any symptoms. The hope is that such warning will allow doctors to treat the patient before things get serious, avoiding hospitalization by, say, adjusting medications. Heart failure is just the most recent use for pacemakers. The lower chambers of some hearts are subject to sudden life-threatening storms of quivering, called ventricular fibrillation that set the different chambers contracting in an uncoordinated fashion. Implanted cardioverterdefibrillators, or ICDs, use software algorithms to look for signs of trouble in the heartbeat and deliver an electric jolt to set things right again. A wireless connection to a cardiologist can help here, too. About 22 million people worldwide suffer from heart failure ICDs made by Biotronik GmbH and Co., in Berlin, use an approach to wireless monitoring that is a bit more hands-off than Medtronic's CareLink [again, see A Networked Heart]. Without requiring the patient to place an antenna over her chest, the ICD automatically transmits its data to a special external cellphone, using a 402- to 405-MHz frequency, which passes through skin and tissue with minimal attenuation. The cellphone then e-mails the data directly to a monitoring center and from there to the doctor.

Conclusion Preparing Today to Meet the Challenge of Tomorrow Digital home technologies can play a key role in helping to meet the challenge of caring for an aging population. The digital home electronics that will be part of people’s everyday lives for other purposes, such as entertainment and communication, can also be used to deliver health and wellness applications, allowing older adults to age in place and reducing U.S. healthcare costs, which have soared to more than $1.5 trillion annually. Companies are contributing to the development of the digital home technologies for aging in place, through R&D investments, funding of university research, participation in organizations and consortia, and by catalyzing industry, university and government players to join in a collective effort to meet the challenge. The involvement of the federal government - through funding research and breaking down obstacles to innovation - will be essential to success. By being proactive today, we can avert a public health crisis tomorrow. Remote Health Care Monitoring may seem like the best answer to managing the care of the next generation of older people, but those in the health care field need some convincing. Medical practice is conservative and rightly requires evidence that a new approach to health care will work. And those who pay for health care—insurers and governments—want to know if it will really save money, and how much. Ultimately, we can see sensors built into roads, farms, hospitals, factories, office buildings, clothing, swimming pools, baby cribs, vehicles and even bandages - a computing infrastructure that consumers around the globe can tap into and take for granted. But research is still in its infancy, and pursuing this goal will require long-term collaboration among industry leaders, academia and government. By underwriting sensor network R&D, these entities will fuel viable and scalable solutions to the cresting age wave and multiple other challenges faced by numerous industries and market segments.