‘Home’ Is Where the Heart Is (Part 2)

Mon, 02/24/2014 - 2:19pm
Tony Zarola, Strategic Marketing Manager, Healthcare


(If you haven’t read Part 1 yet, do that first here.)

Many reports, papers, and studies have been written about the benefits of remote health monitoring, but when you look at the number of companies and institutions that are investing time and energy incorporating VSM (vital sign monitoring) into their end systems, you soon realize that the remote health environment is much larger than the traditional home or gym. The out-of-hospital VSM market is growing exponentially and has the potential to outgrow many other market sectors.

A combination of driving forces is enabling VSM deployment across different market sectors including:

Negative driving forces:

  • The need to contain and reduce the spiraling costs of healthcare globally (in the U.S., the spend for healthcare is around 18% of the national GDP)
  • An aging population (for the first time in history, by 2030, people older than 65 will outnumber 5-year olds) is placing an unprecedented burden on the healthcare system
  • Unhealthy lifestyles (obesity is the main cause for the increase in chronic conditions including diabetes, hypertension and pulmonary disease)

Positive driving forces:

  • A communications infrastructure that offers global access to healthcare resources
  • Advancements in technologies that make remote health monitoring feasible and compliant to our lifestyles
  • A growth in the support infrastructure that provides real-time motivation to maintain a healthy lifestyle
  • The realization that preemptive health monitoring can reduce the length and occurrence of in-hospital stays

The expanded definition of “home” vital sign monitoring (VSM) market

The market sectors that are exploring how they can participate include:

  • Hospitals (driving monitoring into the home)
  • Assisted living facilities
  • Sports facilities, including athletic fields
  • Schools/educational institutions
  • Insurance/corporate-sponsored wellness programs
  • Military
  • Automotive industry
  • Consumer industry (smartphones, smart watches, gaming)
  • Animal health* (livestock management, pet care)

*While not technically part of the human healthcare problem, animal health monitoring is a rapidly growing market that is utilizing some of the same technological advancements as human health monitoring devices.

How vital signs will be measuredThere is commonality in the vital signs monitored across these market sectors; however, environmental constraints and how the information is interpreted and used has significant impact on the efficacy of any monitoring device.

The following highlights a few of the market subsets and the goals, constraints, and proposed technologies that will enable the desired vital sign measurement and monitoring capabilities.

One of the fastest growing market sectors for health monitoring is sports and fitness. The two categories of monitoring are:

  • Fitness
  • Safety

Traditionally, fitness management has been performed using heart rate monitoring devices in the form of a chest strap or in the handle bars of a treadmill machine. Electrode-based heart rate monitoring remains a popular approach to recording cardiac output. What is changing, however, is the way electrodes are formed. For instance, new textile technologies that use conductive material in the weave of the fabric enable larger surface areas on the body to pick up the bio-potential signals.

Analog Devices’ AD8232 HRM AFE functional block diagramAgain, body-worn monitors require low power, a small size, and no compromise on performance. A heart rate monitor (HRM) like AD8232 effectively acquires biopotential signals while maintaining low power usage and low cost. Key features include leads-off detection, fast restore, right leg drive, and a flexible architecture that enables the configuration of external filters to help reduce the effects of motion artifacts.

Optical devices that detect photoplethysmograph (PPG) signals offer another method for measuring heart rate. A PPG device typically worn on the wrist uses the ulnar artery to detect blood flow and hence, determine heart rate. This method is used in a number of monitoring devices targeting athletes.

Other vital signs that contribute to the determination of energy exertion, calorie burn, and general fitness level include:

  • Activity monitoring (low power MEMS accelerometer)
  • Respiration monitoring (thoracic impedance- or MEMs-based)
  • Perspiration measurement (skin impedance)
  • Temperature (surface flux and core)

Analog Devices’ ADXL377 MEMS accelerometer accurately measures concussion-level forces in contact sportsWhen it comes to sports safety, concussion ranks as one of the highest sports-related injuries. Up to 3.8 million sports-related concussions occur in the United States every year according to the Centers for Disease Control (CDC), leading the organization to conclude that sports concussions in the U.S. have reached an “epidemic level.” As we learn more about the long term effects of repeated concussions, from high school through amateur sports to the professional game, the call for technology to help detect the severity of a head impact is increasing. Where to locate the impact sensor is a challenge. For sports such as American football, the problem is easily solved—MEMS inertial sensors can be placed in the helmet to detect impact from multiple locations. In the case of car racing, MEMS inertial sensors are placed in driver earpieces. However, not all impact sports require helmets or head gear. For those athletes, concussion-level impact is being detected and measured using impact sensors embedded in mouth guards.

While detecting a head impact is a major step toward managing concussions, there is a need to prevent impact to the head. Research in the area of helmet-based air bags is in the works and may hopefully become commonplace one day.

The Workplace
The workplace may not be the first environment associated with health monitoring, but with the cost of provisioning health benefits at the corporate level, work-related health management programs are being introduced as a means to reduce healthcare benefits costs. In North America, insurance companies are leading the charge by introducing programs that employees can register for to track their weekly or monthly physical activity level (e.g., number of steps/week). Achieving goals translates into rewards in the form of reduced insurance premiums or some other financial incentive. The company sponsoring the program can reduce the cost of their benefits programs, and there is growing evidence to suggest that a healthy/fit work- force is a productive workforce.

The most common form of workplace health monitor is the pedometer. While these small devices can be carried in the pocket or tied to the shoe or hip, the embedded technology makes them smart enough to discern if the wearer is walking, running, or simply making erratic movements to try and fool the device.

Another area of workplace health management is stress detection. According to a report from the National Institute of Occupational Safety and Health Association (OSHA), three-fourths of employees believe that workers have more on-the-job stress than the previous generation. Stress can be measured through galvanic skin impedance and heart rate. Technology can be embedded into every day work-related devices such as the computer mouse or keyboard to measure these required vital signs. Analog Devices’ ADuCM360 low power, precision analog microcontroller provides an ideal system-level solution for accurate measurement of galvanic skin impedance. The ADuCM360 is a fully integrated, 24-bit data acquisition system that incorporates dual high performance, multichannel, sigma-delta analog-to-digital converters (ADCs), a 32-bit ARM Cortex™-M3 processor, and Flash/EE memory on a single chip.

Military personnel are exposed to the harshest of conditions, and the ability to remotely measure their vital signs through body-worn sensors is critical for their protection and wellbeing.

Analog Devices’ ADuCM360 fully integrated, 24-bit data acquisition system offers accurate measurement of galvanic skin impedance.On the battlefield, a remote triage area for medics is vitally important to the safety of the medical team and the individuals affected. Being able to prioritize treatment amongst many and determine who needs medical attention first before stepping into a combat area can save lives.

Heart rate monitors, activity monitors, temperature sensors, stress indicators , and impact sensors can be used individually or collectively to monitor the health of our servicemen and women.

The Smartphone
We’ve touched a little on the use of smartphones as a means to help with health management through third-party applications. Using the smartphone as the medical monitoring device itself is an intriguing concept to many — not least the smartphone developers themselves. Technology already exists within the smartphone in the form of an embedded accelerometer to support pedometer, activity monitoring, or sleep monitoring applications. The CMOS camera sensor can also be used as a simple HRM through multiple techniques of image analysis to detect changes in blood flow. However, these technologies tend to burn power — not necessarily through the sensor but because of the way the technology has to be implemented to support these applications. This is a problem because smartphone power must be reserved for email and social media applications. Devices like ADI’s AD8232 single-lead HRM AFE and ADXL362 low power, 3-axis MEMS accelerometer have the size, performance, and power profiles necessary and, when embedded into a smartphone, can independently measure heart rate and motion, respectively.

Accessories are a realistic proposition for adding vital signs monitoring to the smartphone. Health monitoring devices that can plug into the USB or audio ports, or connect via Bluetooth, are rapidly becoming available.

Much research is underway to determine how we can monitor our vital signs effectively in the confines of our car. Emotion and stress sensors, heart rate monitoring, temperature sensing, C02 sensing, glucose monitoring, Sp02, and pollen are all potential applications targeted at improving driver safety and making the driving experience more pleasant.

But the challenges exist … how do we take the measurements? Through the steering wheel, seat, safety belt? Using camera technology, electrodes, optical sensors, MEMS? What do you do with the information once you have it?

Telling the driver he might be having a heart attack could lead to panic and further disastrous consequences. However, telling the driver to wake up is a practical application for heart rate monitoring.

A future automobile may offer HRM and galvanic skin impedance measurement using sensors in the steering wheel, seat, or safety belt.The steering wheel provides an obvious location for mounting vital signs monitoring equipment — products like the AD8232 HRM can connect to embedded electrodes in the material covering the steering wheel. Additional, or even the same, electrodes can be used to measure the galvanic skin impedance to determine stress and emotion levels. Analog Devices’ ADuCM360 low power, fully integrated, 24-bit data acquisition system-on-a-chip provides a platform for measuring the galvanic skin impedance and converting the output of the AD8232 to a digital format.

In summary, the concept of “home monitoring” is taking on many new dimensions. With advanced technology, evolving support infrastructures, and the unquestionable need for healthcare cost reductions, vital sign monitoring will become a natural part of our daily lives, potentially available when and where we need it, blending into our personal telehealth ecosystem. Whether it’s for managing disease outside of a hospital or clinic, supporting independence to the aging population, motivating healthy lifestyle habits, improving personal safety, or simply providing peace of mind, Analog Devices is at the forefront of this market dynamic, developing sensor and signal conditioning technology solutions to enable next generation vital sign monitoring.

Please visit to learn more about ADI’s health monitoring products (ADuCM360, AD8232, ADAS1000-3, ADXL377, ADXL362, ADT7320).


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