The Agenda of Wearable Healthcare.

Driven by cost and quality issues, the health system in the developed countries will undergo a fundamental change in this decade, from a physician-operated and hospital centred health system to consumer operated personal prevention, early risk detection and wellness system. This paper sketches the vision of a ‘Personal Health Assistant’ PHA, opening up new vistas in patient centred healthcare. The PHA comprises a wearable sensing and communicating system, seamlessly embedded in our daily outfit. Several onbody sensors identify the biometric and contextual status of the wearer continuously. The embedded computer generates the ‘Life Balance Factor’ LBF as an individual feedback to the user and to the surroundings affording an effective prevention, disease management and rehabilitation also in telemedicine. The state-of-the-art enabling technologies – mainly miniaturization of electronics and sensors combined with wireless communication and recent developments in wearable and pervasive computing are presented and assessed concerning multiparameter health monitoring. 1. From Mainframe Healthcare to the Personal Health Assistant PHA? As a global trend, healthcare related costs create an increasing pressure on the economies in the developed countries: In 2002, for example, the US Americans and the Germans expended about 13 percent of their national income for healthcare . Considering the demographic development, an increase to 20 percent in 2025 is expected. The elderly population over age 65 will increase almost twice as fast as the rest of the population, whereas the percentage of the population under age 65 declines . With the longevity also the agerelated disabilities and diseases are rising. Mainly because of the hospital costs, a German seventy-year-old patient costs five times more than a twenty-year-old patient. As another example, the US Alzheimer Association calculated an increase of annual cost to businesses caused by Alzheimer’s disease from $ 33 billion in 1998 to $ 61 billion in 2002 . In addition to the demographic pressure, people expect continuously high quality in healthcare, through the access to improved medical therapies, drugs or home care. The fact that the ratio of workers to retirees will drop to 2:1  will impose increasing pressure upon the social security systems. These figures should briefly illustrate that the health systems in the developed countries have to change radically in the near future, driven by quality and cost issues . Andy Grove, Intel’s legendary founder, has characterized the current situation of healthcare by the metaphor of mainframe computers, the dominating systems in the sixties : few, expensive powerful machines, localized in a dedicated environment and operated by skilled specialists acting as interface between the user and the computer. Personal computer in the eighties and mobile phones and PDAs in the nineties have outstripped mainframes in quantity and performance. Could we imagine a similar trend, from mainframe healthcare to a personal health assistant PHA? Recent developments in micro-and nanotechnology, low power computing, and wireless communication as well as in information processing have paved the way to non-invasive and mobile biomedical measurements and health monitoring [6] providing the technological platform for the PHA. A scenario may help to sketch the potentials of these emerging technologies. As described later in this paper, manifold smart miniaturized sensors, connected by a wireless or wired body area network to data processing and communication devices will be embedded in our daily outfit. This wearable personal health assistant (PHA) monitors continuously the wearer’s vital signs like heart rate, heart rate variability, temperature and motion activities. The combination of vital parameters with the wearer’s context, the activity and sleep patterns, social interactions IMIA Yearbook of Medical Informatics 2005: Ubiquitous Health Care Systems. Haux R, Kulikowski C, editors.