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Telehealth age dawns

Posted: 01 Dec 2008 ?? ?Print Version ?Bookmark and Share

Keywords:telehealth? wireless technology? networking? Bluetooth?

IMEC's wireless ECG patch is undergoing validation in hospitals.

Nearly half the population suffers from at least one chronic disease in the United States. And the cost of treating these patients accounts for more than 75 percent of the nation's $2 trillion medical bill, according to a 2005 report from the U.S. Centers for Disease Control and Prevention.

Many of these dollars are spent on high-tech treatments and surgeries. But billons pay for less dramatic but far more numerous events, such as routine doctor visits, lab tests and other monitoring procedures.

In the next few years, many of those spiraling costs could go into remission.

Wireless monitoring
Chronic disease monitoring and treatment is one part of the health care bill that doesn't have to perpetually increase. This sunny diagnosis can be made in large part because remote monitoring using wireless technology is finally getting its interoperability act together worldwide.

Telehealth technologies are being developed and deployed to reduce visits to hospitals and doctors' offices and improve patient health with lifestyle coaching. This first telehealth wave will be quickly followed by a second, in which highly sophisticated sensors attached to and implanted in the body will communicate over body-area networks. The focus will shift from providing lifestyle modifications to delivering just-in-time, life-saving information to physicians.

Telehealth will create opportunities for design engineers. The market for remote personal health monitoring will reach $5 billion in 2010 and explode to $34 billion by 2015, according to Elizabeth Boehm, senior analyst at Forrester Research Inc.

Initial guidelines
The first big step will come at the end of this year when the Continua Health Alliance releases its initial guidelines for wireless and wired data transport between monitoring devices and health care providers. While these guidelines will involve familiar devices such as blood pressure cuffs, glucose meters, pedometers, thermometers and weight scales, the data transport structures are applicable to far more sophisticated devices.

Next-generation devices are already being deployed in hospital trials. One example is a wireless ECG monitor designed by IMEC that integrates electrodes, a biochip sensor, MCU and radio into a package about the size of a very thin wristwatch. Algorithms running on the patch's processor monitor for heart arrhythmias 24/7. It can run for a week on a small battery.

The concept becomes even more interesting with technologies still in silicon prototype stage, including ultralow-power DSPs tuned for biomedical signal analysis, low sample rate/high-resolution ADCs, UWB radios that consume two orders of magnitude less power than Bluetooth and MEMS-based energy harvesters that will replace batteries.

First-wave: interoperability
Continua Health Alliance's mission is to ensure interoperability between health monitoring devices and home-based hubs that relay the data from the devices to health care providers.

First-generation devices that comply with Continua's Version One Guidelines will provide secure transport of sensor data over wireless Bluetooth or wired USB links, said David Whitlinger, President of Continua. The local hub receiving the information can be a cellphone, PC, advanced STB or specialized device.

The guidelines are in final review, with publication expected by year-end. They define use cases for monitoring devices and specify compliance with the Health Device Profiles created by the Bluetooth SIG and USB Implementers Forum.

Continua has made significant contributions to the device profiles, said Whitlinger. The guidelines also specify compliance with the IEEE 11073 standard, which defines protocols and data structures for the secure transport of medical data.

Several companiesincluding Bluegiga, Broadcom, Cambridge Consultants, Cybercom, MindTree, Panasonic Electronic Devices, Stollmann and Toshibaalready offer solutions that integrate software and silicon for a Continua-compliant Bluetooth/USB/IEEE11073 module. And a set of reference designs for first-generation monitors and a tool kit that includes Bluetooth and USB silicon have been created by Cambridge Consultants.

"Customizations might involve using your own display or reading data from an existing sensor," said Paul Williamson, head of Cambridge Consultants' wireless medical group. Once the customization is completed, firmware can be ported to CSR's Bluecore chip. While Bluetooth and USB have security provisions, Williamson said, they're focused on data integrity. The IEEE 11073 protocols ride above the transport, and additional customization may be required to meet local regulatory mandates to protect patient health records.

The telehealth ecosystem is based on remote monitoring.

Second-wave: sophistication
Cardiovascular disease is the most common cause of death and disability in the United States and Europe. Heart diseases including cardiac arrhythmias cause 30 percent of all U.S. deaths. The most common ways to diagnose an arrhythmia are point-of-care ECG monitoring or the wearing of a portable but uncomfortable device that records heart activity for 24 hours.

A miniature, inconspicuous ECG monitor with wireless connectivity would save lives and reduce emergency medical costs by continuously scanning for arrhythmias. For maximum benefit, the device would also analyze the ECG signals. Local analysis would make it possible to take appropriate action, from storing the data to alerting the patient and the health care provider of an impending and potentially serious event.

Work on similar devices is under way elsewhere, but the IMEC design is already being validated in European hospitals. IMEC's ECG patch is in development in the Human++ program at Holst Centre, which focuses on technologies for wireless autonomous sensor systems for health care monitoring.

IMEC's cutting-edge ECG patch features wavelet-based ECG analysis software that runs on Texas Instrument Inc.'s MSP430 f1611 MCU. Major hardware components include a Nordic Semiconductor Inc. nRF24L01 radio, a bio-potential-chip sensor, electrodes, an ADC and a fork antenna all integrated on a flexible polyimide substrate. This system is in turn integrated into textile to achieve flexibility and stretchability. It can run for a week on a 20mm x 20mm x 5mm battery, according to Bert Gyselinckx, IMEC program director.

Average power consumption is around 2mW. But as impressive as the ECG patch is, there's plenty of room for improvement, particularly in reaching aggressive ultralow-power goals. Reducing power is always a challenge. "In theory, you want to do more processing and less communication," said Gyselinckx, "but with today's technology that doesn't work because you can't properly duty-cycle the processor or the radio. We need to develop processors and radios tuned to duty-cycling so they can be switched off and on very quickly without losing power in start-up and shut-down."

Researchers are working on that and improvements from new technologies such as UWB radios, which reduce power on the transmit side by 10-100x compared with the 2.4GHz Nordic chip. The Nordic chip is already an ultralow-power device, consuming much less power than Bluetooth.

IMEC has developed prototypes of UWB radios and DSPs tuned for duty-cycling and biomedical signal analysis, Gyselinckx said. An ultralow-power ADC that uses a 100kHz to 200kHz sampling rate with a 12bit to 16bit resolution is in development. Other technology frontiers include the sensors themselves and energy harvesting-extracting energy from the body, thus eliminating the need for batteries.

Broader challenges
Although the road to technology solutions is clear, telehealth also faces cultural and institutional hurdles. Carlton Doty, a principal analyst at Forrester Research, cited concerns about regulatory compliance and malpractice at health care providers and a lagging IT infrastructure on the back-end. According to Doty, 65-70 percent of all U.S. physicians practice in groups of less than 10 doctors. These smaller providers still struggle to establish an IT-based medical records system, he said. Reimbursement shortfalls are another factor causing both large and small providers to delay IT spending.

None of these impediments is insurmountable and advances in technology will make the need to implement them at an institutional level a no-brainer.

- Jack Shandle
EE Times

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