Medical monitoring gets personal, goes mobile

The trend towards technology "personalization" continues, and it is heading into new areas. It began with personal computers in the 1980s, went on to desktop publishing, and has extended to our ubiquitous voice and data communications via smartphones. We are now seeing this trend branch into personal medicine and medical devices which are no longer confined to formal clinical settings or occasional use.

Vital signs monitoring (VSM) of individuals includes both those who have medical issues (remote health monitoring), as well as those who do not yet but are nonetheless concerned about their health and well-being (personal health management). Those who have medical issues want point-of-care monitoring and don't want to be "tied down", while those who are well are often on-the-go individuals, and expect their VSM to be a relatively transparent part of their daily lifestyle and routine.

We are entering an era where individuals want to monitor their vital signs at home, at work, in the car, at the gym, on the sports field, and more. With these new expectations come new challenges for system developers. The increasing level, diversity, and spread of VSM is due to a synergistic combination of improvements across multiple areas: sensors, analog front ends, signal processing, and multiple wireless connectivity options. Many of these advances are driven by Moore's law and its corollaries, and are somewhat predictable, such as advances in highly capable, integrated analog front ends.

The appearance and impact of MEMS devices as compact, easy-to-use, low-cost, high-performance sensors was not in the crystal balls of many industry forecasters and pundits. Consider this: what began as an application-specific, tightly focused sensor technology for one application–namely, automotive airbags–has spawned an incredibly diverse array of sensors and resultant applications including health and safety monitoring at clinical levels using personal venues.

The challenge for designers goes well beyond the electronics alone. Having these devices available and useful in so many diverse settings puts new demands on product packaging, materials, sensor interface, user interface, ease of use, reliability, run time, regulatory certification (in some cases) and, of course, cost.

Note that the use of these sensors in mass-market, consumer products affects more than just the obvious electronic-design challenges. Packaging and appearance must shift from just functional to esthetically acceptable and even fashionable, while still meeting the technical requirements. The "soft" design mandate to also be stylish adds yet another dimension to the engineer's list of product design challenges and constraints.

In addition, the in-use environment for these devices is less controlled, less respectful, and more varied than in static, clinical settings. Users may toss the devices, inadvertently abuse them, or get them dirty or wet, even when they are not designed for such handling. In addition, the devices often need to be designed to be used or worn 24/7 on the hip, wrist, upper arm, shoe, or elsewhere, and without battery-replacement or charging issues.