Combining the right features and functions can result in a product that goes well beyond a simple fitness tracker.
According to Juniper Research, some 60 million fitness trackers will be in use by 2018, more than tripling the number sold in 2014. And if analyst CCS Insight is right, the total wearables market will rise to 172 million devices by 2018. Hence, fitness trackers will account for more than one third of all wearable devices.
Well-known examples like Fitbit and Xiaomi’s MiBand are clever devices for measuring heart rate and activity levels, sometimes making a reasonable estimate of how many calories are burned for a given activity level. While these wristbands have been subject to a lot of media attention, more complex wearables have been emerging that gather and transmit data from a variety of biometric sensors. Their use is no longer limited to helping people assess their activity levels and fitness and share that information with friends via a combination of mobile phone apps and cloud-based services. This relatively new generation of devices is being put to valuable use by the healthcare industry to improve the quality of life, and sometimes even the life expectancy, of patients.
But this isn’t just about improving care. The business case for investing in mobile healthcare – aka mHealth – is very convincing (Figure 1). Again according to Juniper, between 2013 and 2018, remote patient monitoring will have delivered $38 billion of savings globally, cut the number of hospital bed days required by 25 percent, and reduced hospital admissions by 20 percent.
A 2013 report by PWC, commissioned by the GSMA, which represents the interests of global mobile radio operators, is even more bullish about the savings. It suggests that in Europe, mHealth may reduce the care costs for chronic conditions by 30 percent to 35 percent by treating 185 million patients more effectively. In total, mHealth could provide 100 million euros of cost savings in the region and add 93 billion euros to gross domestic product, the organization claims.
It’s not just developed economies that stand to benefit. Another GSMA report says that mHealth could help save 200,000 lives per year in sub-Saharan Africa. Here, the technology is being used to support the fight against malaria, tuberculosis, perinatal conditions, and AIDS/HIV, which together account for 3 million deaths annually. In fact, a 2014 PWC report shows that awareness of mHealth technology is much greater in emerging markets (61 percent) than in developed ones (37 percent).
What can be measured
While the presence, or otherwise, of a heartbeat is the most basic vital sign in human healthcare, sophisticated sensors can now capture many other kinds of physiological data, including heart rate, heartbeat patterns, respiration rate, blood pressure, blood oxygen levels, and more. Wearables may also be linked to sensors implanted inside the body.
The healthcare industry is trending toward creating wireless networks of body sensors, or wireless body area networks (WBAN). It can also be helpful for medical professionals to access data about the location of patients, their mobility, and if they are accident victims. Location data may come from proprietary wireless systems within a hospital environment, from Wi-Fi or cellular radio networks, from satellite tracking systems, or from a combination of these technologies. 3D accelerometers are used to detect when a patient is involved in sudden unexpected movement that could be the result of an accident.
mHealth wearables, which will develop in many different shapes, sizes, and forms, may sometimes be standalone devices that simply remind patients to take some form of action, perhaps taking medication or renewing prescriptions. However, the vast majority of them will need to be connected to an application that will analyze and communicate data from sensors. Applications may be hosted on a patient’s smartphone, but the major mHealth benefits will be derived by delivering data over the Internet to cloud-based services that are accessible to medical professionals.
The aggregation of data from thousands or even millions of patients offers the medical professional new insights into medical conditions. For example, U.S.-based iRhythm has developed a solution for detecting, characterizing and diagnosing arrhythmia, or irregular heartbeat. Using sensors taped the chests of patients and data then delivered via a smartphone or its website, the company has collected more than 51 million hours of heart beats from ECG recordings and is using the results to better understand arrhythmia, and to refine its analysis algorithms.
Location-aware technologies in mHealth
Location awareness adds another dimension to physiological sensor data. If a healthcare professional is signaled that a patient is in distress or danger, knowing precisely where that patient is located, ideally without having to rely on voice communication, can make a life-or-death difference.
One example of a company that’s embracing various technologies to deliver mHealth is Numera. Its Libris+ mobile purse (Figure 2) provides fall detection for vulnerable people, principally the elderly. 14.8 million people over 65 fall each year in the U.S., with some 20 percent to 30 percent of these falls resulting in moderate to severe injuries. Libris+, which is normally worn on a halter around the neck, integrates the fall detection sensors with global satellite navigation and cellular radio (voice and data) to communicate problems to a service center and from there to relatives or friends of the wearer so that help is summoned quickly and directed appropriately. Communication can also be manually activated by pressing a button. Electronic weighing scales, blood pressure monitors, and blood-oxygen level detectors can also be connected so that the Libris+ device can become a local communications hub for the user, connected to various physical and physiological sensors.
Combining location-awareness with mHealth
Indoor location data can be derived from dedicated wireless sensor networks within a building or from Wi-Fi hotspots. Outdoors, satellite navigation provides the most consistent global coverage, and its accuracy can be further enhanced by adding cellular network or Wi-Fi router location data.
While many people use “GPS” as a generic term for satellite positioning or navigation systems, it more accurately describes the U.S. satellite tracking system. Global Navigation Satellite Systems (GNSS) is the true generic description, as Russia has developed the GLONASS system, China has BeiDou, and Europe is rolling out Galileo. These systems are often complemented with a satellite-based augmentation system (SBAS), which adds data from ground-based reference stations to that received from satellites.
Adding GNSS location-awareness to mHealth products has its challenges. Users want small, discrete, lightweight devices and they don’t want to have to re-charge batteries frequently, so very low power consumption is essential. Also, this is essentially a consumer market where profit margins are small, resulting in severe cost pressures being placed on component suppliers. Last, but equally important, mHealth device makers are in an innovation race – being first to market with new products can be the difference between success and failure, so ease of integration of location-aware functionality is essential.
A few companies choose to design their own GNSS functionality starting with ICs. However, many will take advantage of the easier integration, shorter time-to-market, and reduction in manufacturing complexity facilitated by ready-made GNSS modules. Two examples of such modules are the u-blox EVA-7M (7 mm by 7 mm by 1.1 mm) and MAX-7 (9.7 mm by 10.1 mm by 2.5 mm). Both can track GPS or GLONASS satellite signals and support SBAS on GPS (Figure 3). The modules don’t need a host microcontroller and require very few external components, so they’re easily integrated into wearables. They provide GPS positioning data with 2.5 m accuracy (4 m on GLONASS), or 2.0 m with SBAS enabled.
Connecting to the Internet
In the fitness market, the most common way to achieve Internet connectivity is by using a smartphone or tablet with cellular or Wi-Fi connectivity. Data from sensors, or sensor modules with integrated processors, increasingly use Bluetooth Low Energy (sometimes called Bluetooth Smart) to link to the phone or tablet because of the ubiquitous Bluetooth connectivity already available in these devices. However, connectivity of wearable mHealth devices may be more critical, particularly when monitoring those who are vulnerable due to age, infirmity, or other health problems. Here, a dedicated Internet connection is usually preferable. If someone forgets to take their smartphone with them, or loses it altogether, communication with the healthcare provider won’t be disrupted.
GTX’s SmartSole integrates GPS tracking and cellular radio into a shoe insole. It’s a discrete solution so it lets healthcare professionals, or relatives and friends, keep track of vulnerable people who may inadvertently wander into danger. In some instances, it’ll enable patients to remain in their own homes, rather than having to be cared for in institutions. Clearly, people suffering from dementia or other brain disorders could have difficulty in managing to use a smartphone or remembering to keep it with them, so a fully integrated solution is the only reliable one. SmartSole (Figure 4) also has a better battery life than many smartphones, operating for 2 to 3 days between charges.
As in the case of GNSS, adding cellular radio functionality demands small size, easy integration, reliable performance, and low cost. Once again, modules often provide the most cost-effective solution. For low data-rate applications, like many mHealth ones, 2G networks have usually offered adequate bandwidth and functionality. However, operators are now beginning to shut down old networks as 4G infrastructure investment accelerates.
To build a degree of future-proofing into mHealth devices, which may be designed for longer operating lives than consumer products focused on fitness rather than health, it’s now desirable to add mobile connectivity with 3G and 4G modules. The initial incremental outlay is likely to be more than recovered over the end product’s operating life because fewer updates will be needed to accommodate network upgrades. It’s also worth ensuring that whatever cellular radio module is chosen, the board can be easily upgraded later with no layout changes.
The greater the number of functions that can be accommodated on a single piece of silicon or on a module, the more cost-effective the solution. The cost-per-function falls with increasing integration. In the near term, we’ll see even closer integration of GNSS functionality with a range of connectivity options on the same modules, including Wi-Fi, Bluetooth, and cellular. As time goes on, we may even see all this functionality combined within ICs.