What Would Joe Do?
Peggy Aycinena is a freelance journalist and Editor of EDA Confidential at www.aycinena.com. She can be reached at peggy at aycinena dot com.
Imec: Firat Yazicioglu & the Cardiac Patch
May 2nd, 2012 by Peggy Aycinena
For the last few years, the world of Imec Senior Scientist and R&D Team Leader Firat Yazicioglu has revolved around IC design of mixed-signal and analog devices, specifically those used for bio-medical health monitoring, and not just the technical challenges, but the economic and ergonomic aspects as well.
When we spoke recently, Firat said, “At Imec [in Leuven, Belgium] we are looking at all pieces of the puzzle with regards to bio-medical devices. How can you curb the costs, what are the details of the electronics, and how can a wearable sensor offer a solution to the problem of home monitoring for patients with chronic disease? Things like arrhythmia or predicting a seizure before it happens.
“These questions are definitely More than Moore issues that involve both digital and analog content on-chip, signal processing problems, and the need for such devices to run on very, very low power.
“There are many Holter monitors, for instance, on the market today for cardiac monitoring. They run for about 24 hours on a battery pack, but are inconvenient when the battery pack dies, plus the wires [in such large devices] cause artifacts and the signal can be lost. It’s what we refer to as signal detecting in ‘horrible’ conditions.”
(Editor’s Note: Holter monitors, per the NIH website are like portable ECG Machines. They are strapped to the patients chest and worn for up to 48 hours, keeping a non-stop record of heart activity, and are then returned to medical professionals for data download and analysis.)
Firat continued: “These Holter monitors of the past were a royal pain. It was a big thing you wore strapped to your side, with wires hooked up to your arm. The device we’ve developed, however, is small and portable. It basically looks like a plaster patch that can stick on the body. It can be worn for anywhere from 1 week to 1 month. The skin adhesive has been somewhat of a challenge to develop, because we needed something that can be up against the skin for up to a month without irritation.
“But the bigger challenge has been the electrodes. If they become too dry, they shift about on the skin and create signal disturbance, so we’re working with gel-based electrodes and studying the signal to distinguish between noise and regular cardiac signals.
“What you need for arrhythmia detection is the ability to distinguish between ambient noise and the signature of an irregular ECG signal. When a patient is lying still on a bed these problems are straightforward. The difficulty comes when the patient is up and going about their normal lives, but this is when cardiac events happen.
“We’re not tackling these cardiac monitors as an engineering challenge, but as an app challenge. We’re working with low-power Bluetooth and local data processing in both the analog and digital domain to create SOCs that run [autonomously], even if communication with the doctor’s office or hospital is not easily available.
“The knowledge is created locally in the sensor on the patient, and then the extracted knowledge is streamed from the local conditions to the doctor [by way of the patient’s computer or smart phone].
“Of course, the doctor will not have to look at the data 24 hours a day, 7 days a week. Instead, we want the local device to interpret the signals themselves, and then let the computer or smart phone know when to notify the doctor. Yes, human intervention is still relevant, but this is an excellent use of the low-power devices being developed today. That’s why we refer to it as an app.”
“You don’t even have to go to the doctor now to have your blood pressure checked. Now wearing this monitor patch, when your blood pressure goes up the doctor will be notified.”
And who is funding this work at Imec?
Firat said, “Three types of companies. The large consumer electronics companies, because it’s like a hardware extension to the smart phone for both stress and cardiac monitoring, which can be viewed as as app add-on to the device.
“Secondly, the mixed-signal companies are funding this work because they will provide the circuits. These types of things will become their next generation bread and butter. And of course, the third group includes the medical devices companies.”
What about the health care industry? Will they be willing to foot the bill for these cardiac ‘patch’ devices?
Firat said, “When people get used to wearing these patches, they’ll push their health insurance companies to expand the coverage to include the patch. People will buy them, and use them, and if the devices are priced at just $25 a piece at places like Walgreen’s, they’ll become commonplace. People will definitely begin to use these things if they’re both inexpensive and useful.”
What kind of devices are already out on the market?
Firat said, “Corventis is one of them, they have a patch. There are a number of other companies with similar devices, but it’s our experience that they only work for a day or so, are similar to the Holter style device, and require the patient to deal with a call center [to monitor the readings]. These are not made for widespread use.
“Additionally, none of these devices are disposable, some get sent back to the manufacturer to be reconditioned, while what we’re doing only requires a single SOC and one standard radio transmitter, involves a standard interface, and is interoperable across many platforms. Most importantly, the Bill of Materials for our device is in only in the tens of dollars, so when viewed in the context of a possible volume market is not expensive.
“This is particularly true in developing countries where chronic disease is on the rise. Those geographies, in general, have leapfrogged over land-line phones, so these smart phone-based health monitoring devices are ideal.”
So going forward, what does Firat and the team at Imec hope to achieve?
He said, “We want the device to be even smaller, even more comfortable, and to run on even lower power. In other words, we want comfort for the patient and we want to reduce the number of components per patch.”
“We’re working to something disposable and cheap – like a smart band-aid. It’s going to take a while longer, clearly, because we need a large ecosystem to support these devices, and many suppliers. Everybody today accepts the idea of a stress patch.
“We want to expand that to wide acceptance of a cardiac patch as well. It will require a change in behavior of the patients, but also of the doctors, but we are confident this will happen.”
Note: If you want to see Imec’s cardiac patch in operation, here’s the video …