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Wireless networks pave way for e-health era

Posted: 01 Nov 2007 ?? ?Print Version ?Bookmark and Share

Keywords:wireless network? e-health? Bluetooth?

Researchers increasingly share a vision of a coming revolution in health care. Today's services controlled by physicians and hospitals will give way to a new model in which consumers directly access devices and services on the Internet or their emerging home and personal area networks.

The diagnostic and therapeutic equipment now locked up in hospitals will someday be available on home or public networks, according to a leading University of Washington professor working to enable the move. This shift demands not only changes in technology, but upheavals in public policy and business models, so just how and when the so-called e-health era will arrive is still uncertain.

What is clear is that researchers believe consumer wireless devices will be the frontline of a future system focused on preventative care. More than a dozen papers from researchers around the globe described separate efforts toward that vision at last August's conference of the IEEE Engineering in Medicine and Biology Society.

Ambient devices
Several efforts prototyped so-called ambient devices that continuously monitor health signs over wireless networks without a user's intervention. For example, researchers at Seoul National University embedded the electronics for a wireless electrocardiography (ECG) machine and other monitors in a desk chair to test for signs of ailments such as hypertension.

Kanazawa University in Japan went one better by creating a simulated home environment in a lab with monitoring devices embedded in pillows, slippers, bathtubs, bathroom floors and toilets. The devices tracked everything from blood pressure and weight to ECG patterns and whether subjects got a good night's sleep.

Intel Corp.'s digital home group reported on a project in Ireland to define digital systems for assisted-living care. The Technology Research for Independent Living (TRIL) program is conducting clinical trials to determine which technologies it will put into a prototype environment late next year. More than 60 researchers are involved in the multimillion-dollar, three-year effort.

Separately, Intel is also seeding researchers with a small Zigbee sensor network module called Shimmer to aid in such investigations. "A lot of researchers have great ideas then wind up spending all their time building hardware," said Michael McGrath, a senior research technologist at Intel Ireland. "We'd like to provide them the hardware and let them focus on doing research."

But for Yongmin Kim, professor of bioengineering at the University of Washington in Seattle, it's all about building the hardware. Kim's group has secured a grant from the Bill and Melinda Gates Foundation to create a $2,000 point-of-care system that could test for health problems ranging from HIV to influenza using disposable modules. The device would replace lab gear in developing countries that would otherwise cost tens of thousands of dollars. The group is also working on a $2,000 ultrasound machine that could diagnose common ailments without requiring a human expert to interpret the images.

It could take five years or more for the devices to be ready for use in a doctor's office, and even longer for them to become consumer products, Kim said. "It will take 10 years to move these systems from primary-care offices to the home," he said.

Wearable monitors
Other researchers are taking it a step further and developing wearable devices using various heart, breath and motion sensors. Researchers at Harvard Medical School, for example, described how they used multiple wearable devices with embedded accelerometers to measure changes in symptoms among patients with Parkinson's disease. Several devices, the size of small MP3 players, were strapped onto a patient's arms and legs and linked via Zigbee to gather data on changes in shaking symptoms over a period of weeks.

"Doctors can use this to make more informed decisions about which drugs at what levels to prescribe, and to better monitor the effectiveness of those prescriptions," said Paolo Bonato, director of the motion analysis lab at the Spaulding Rehabilitation Hospital Network in Boston and an expert in wearable medical devices.

In other papers, researchers reported on their use of wearables to track sleeping disorders, exercise habits and other issues. Nokia displayed a flexible sensor platform it designed based on an Altera Cyclone II FPGA to serve such applications. The device, the size of a fat wristwatch, supports a number of sensors linked over Bluetooth.

IEEE group defines personal-health data standard. Protocol maps wireless technologies to medical data formats.

"It's quite a general platform, but the FPGA is the big bottleneck for power consumption," said Tom Ahola of Nokia Research Center in Finland. A next-generation platform will use an Actel Igloo or QuickLogic PolarPro FPGA and the low-power version of Bluetooth formerly known as Wibree, he said.

Other researchers reported on their work designing electronic patches or active garments. Researchers from the Osaka Electro-Communications University described a Bluetooth patch with motion sensors using off-the-shelf chips such as an Atmel AVR MCU and Rabbit Semiconductor transceiver. Two Belgian brothers behind startup Therasolve showed their concept for a programmable patch that could alert users when it is time to change the patch or take other medications.

Several European researchers described efforts to embed biosensors in clothes for continuous monitoring of health signs. The European Commission has funded work in the area under programs such as ProeTex, which is developing active shirts with UWB links for public-safety workers.

Active garments
Researchers are making progress developing conductive yet flexible yarns based on organic FETs to create active garments, said Annalisa Bonfiglio of the University of Cagliari in Italy, the coordinator of the ProeTex project. So far developers have only created primitive electronic devices such as ring oscillators and diodes with the yarns, which typically require tens of volts, she said.

"We are still far away from textiles with complex sensors that are washable. Researchers in this field are effectively at the single-sensor stage and years away from anything like a microprocessor," said Olaf Such, a director of Philips Research Europe and head of its biomedical sensor department.

Motion artifacts represent an even bigger technical hurdle for this sector, said Such. The dry electrodes linked via wireless connections used in wearable devices generate relatively poor, noisy signals, yet the devices are expected to accurately analyze and recommend actions based on the data without the need for a doctor's intervention.

The medical industry needs a benchmark for testing new algorithms that reduce the motion artifacts created in wearable devices. The work could be patterned after existing benchmarks and databases for ECG algorithms, Such said.

There's no shortage of wireless technologies for wearables. Researchers showed devices using Bluetooth, RFID, UWB and Zigbee. Many papers also described systems that use the cellular network to link doctors or first responders to health monitoring systems in remote hospitals. However, each wireless link has its issues, and researchers are working to create interoperability layers between them.

Reliability
"No wireless technology is 100 percent reliable, and you have to consider that fact when you are designing these medical systems," said Peter Chadwick, a senior RF consultant for Zarlink Semiconductor, who also chairs a European standards group on wireless for medical devices.

Intel's TRIL project in Ireland will use Bluetooth in assisted-living homes, but the company admits it needs a custom version of the technology for optimal use in that environment. Bluetooth cannot span even the smallest Irish cottage, must be kept at least 1.8m from any microwave to avoid interference, and needs to be carefully aligned to provide the best range, the company found.

In an effort to create some commonality at high levels, an IEEE 11073 subcommittee is developing a mapping for different wireless technologies to an existing standard that defines medical data formats. The groupwhich includes members from Intel, Philips and Sharpis about two months behind in its plans to have a complete standard early next year.

- Rick Merritt
EE Times




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