Philips Research Technology Backgrounder


MyHeart project

When it comes to people’s health, the first and foremost rule is that prevention is better than cure. Where illness cannot be cured, the second rule is that disease management is better than hospitalization. In addition to improving the quality of people’s lives, exercising these rules frequently has the added benefit of reducing healthcare costs, thereby freeing up hospital resources to care for critical patients. This is particularly true in the case of chronic cardiovascular disease, which currently affects more than 20% of Europe’s population and is one of the world’s biggest killers.

The MyHeart consortium, comprising 33 industrial, research, academic and medical organizations from 10 different European countries, is working on both the preventative and management aspects of chronic cardiovascular disease. It is doing so through the application of technology that has been designed to monitor vital body signs, and software that can be programmed to analyze the measured data in relation to heart function and provide direct feedback to users or clinicians.

The MyHeart project, to which Philips Research is a major contributor, is one of the largest biomedical and healthcare research projects within the European Union and runs until the end of 2008. It will spend a budget of around 35 million Euro, of which 16 million Euro is funded by the European Union as part of the EU 6th Framework Program.

Over the past two years, the MyHeart project has identified four key product concepts that are likely to bring the most benefit to the prevention and management of chronic cardiovascular disease:
  1. Activity Coach
    Maximizing the enjoyment and health benefits of regular exercise. Targeted primarily at healthy individuals.
     
  2. Take Care
    Assessment and reduction of the risk factors for cardiovascular disease through vital body signs monitoring, lifestyle coaching and motivation. Targeted at people who are at risk of developing cardiovascular disease.
     
  3. Neuro Rehab
    Improving and shortening the rehabilitation period through physical and mental exercises, targeted primarily at stroke victims.
     
  4. Heart Failure Management
    Improving quality of life and life expectancy for heart failure patients by early detection of deterioration in their condition (decompensation) and improved patient management.
     
The principal technology development common to all of these applications has been the development of on-body sensors and electronics for monitoring vital body signs and physical movement. These sensors and electronics have now been integrated into functional clothing and combined with wireless-based telemetry and user interaction systems to produce prototype product concepts that entered user/clinical evaluations in 2007.

Philips Research's main involvement in the MyHeart project so far has been the development of wearable electronics and body sensors that can unobtrusively detect and measure vital body signs such as heart rate and breathing rate, communicate and analyze the acquired data and provide feedback to users or health providers. The prototype systems that it has developed for use in user/clinical evaluations comprise a disease management system for heart failure patients and a sleep monitoring system that can be used by patients suffering from sleep disorders or anyone who wishes to improve the quality of their sleep.

Heart failure management
Heart failure patients frequently suffer complications that currently require them to be hospitalized so that their condition can be stabilized. These complications are typically the result of a process known as decompensation, in which progressive deterioration leads to potentially lethal conditions such as fluid accumulation in the lungs. In many cases, this decompensation remains undetected until the patient suffers noticeable symptoms and visits their doctor.

As part of the MyHeart initiative, Philips Research is developing an advanced heart failure management system with the aim of providing several days advance warning of life-threatening decompensations, giving doctors time to stabilize the condition by modifying the patient’s drug regime rather than having to admit them to hospital.

Like Philips’ current home telemonitoring solution sold in the U.S. for heart failure patients, the system comprises an electronic weight scale and blood pressure monitor, but Philips Research is adding a body vest with integrated textile electrodes and control electronics to measure the patient’s ECG (Electro-cardiogram), and sensors that are placed in the patient’s normal bed to measure heart-rate, breathing rate and body movement while sleeping. All of these devices communicate measurement data via wireless links to a PDA on which the heart failure management software runs. This software guides the user through a daily ritual of taking their weight, blood pressure and ECG measurements, and then combines this data with information from the bed sensors to assess changes in overall heart function. Measurement data could then be delivered to healthcare providers either via the phone network as with Philips current telemonitoring system or via a broadband connection similar to Philips’ Motiva interactive healthcare platform.

One of the key technologies developed by Philips Research relates to the signal processing algorithms needed to extract ECG data from the electrodes built into the vest and bed sensors, which because they must be unobtrusive are somewhat less effective than conventional ECG electrodes. The next development, which will take place during clinical trials, is refinement of the algorithms that predict decompensation to make them highly reliable as well as patient specific.

Sleep monitoring
The same bed sensors and electronics that are used in Philips Research’s heart failure management system can also be used to analyze sleep quality and give users valuable feedback on how to improve it. They therefore have significant application in both the consumer and medical domains.

Measuring heart rate and breathing rate – two of the key parameters needed to assess sleep quality – is not easy. Taped-on ECG electrodes are not only highly obtrusive and likely to keep the user awake, they are also prone to becoming dislodged or disconnected as users roll over in their sleep. The solution developed by Philips Research and Italian textile manufacturer Smartex consists of an electrically conducting pillowcase that makes contact with the user’s head and a similar sheet of material at the foot of the bed that contacts the user’s feet. These two electrodes pick up the minute electrical potential developed between the head and the feet as a result of electrical impulses of the heart. An additional sensor, made from a sheet of pressure sensitive electret material, is positioned halfway up the bed under the mattress cover to detect user movement. This sensor is also sensitive enough to pick up the chest movements associated with breathing and can even detect the ballistic recoil generated by contraction of the user’s heart muscles.

Once again, the key to making the system work is extracting meaningful information from the noisy signals that are picked up by the sensors. The signal processing algorithms built into the system’s measurement electronics must initially distinguish viable measurement periods from non-viable periods – for example, when the user moves his/her feet such that they no longer make contact with the foot electrode. Even during viable measurement periods, the signals that correspond to the heart beat or breathing must be distinguished from noise sources such as movement artifacts. Philips Research’s signal processing algorithms are able to extract these rhythmical patterns from the sensor signals to reliably measure heart and breathing rates.

Combined with information from the movement sensor, these measurements are then used to identify periods of light, deep and REM (Rapid Eye Movement) sleep, micro-arousals and waking periods. Each morning, after downloading information to a Bluetooth connected PDA or tablet PC, the user can access a detailed breakdown of their sleep patterns in the form of parameters such as time of going to bed, time awake in bed, time asleep and sleep efficiency. The system even gives users clues as to why their sleep was interrupted – for example, by periods of snoring.

They can also receive general recommendations on sleep improvement, such as avoiding caffeine drinks before bedtime and creating an appropriate environment in the bedroom. In addition, the computed sleep parameters can be used to develop a personalized coaching strategy for sleep quality improvement that encourages users to adopt a healthier lifestyle – for example, by adopting regular bedtimes that also fit in with their schedule or by selecting favorite techniques such as relaxation therapy. The success of these measures is then monitored by the system and fed back to users, providing an inherent motivation for them to stick to their new lifestyles.

Open innovation
One of the most important things about these developments, and indeed about the MyHeart project as a whole, is that putting together such systems requires a multi-disciplinary approach that brings together hardware engineers, software engineers, textile manufacturers, industrial designers, clinical experts and healthcare providers. Only by adopting the open innovation approach that Philips Research is well known for is it possible to create system solutions that will truly benefit people’s health and wellbeing.