Medical electronics today and tomorrow


Medical electronics smacks of the future but is not a new discipline. Electronic devices have been supporting the frail human body for over five decades since the first artificial cardiac pacemaker was implanted in 1958. But, since the turn of the century, medical technology has accelerated dramatically.

Cheaper, smaller electronic chips have, for example, allowed medical manufacturers to develop products that significantly enhance the quality of life of chronically sick people, allow constant monitoring of elderly people so they can continue to live at home and provide motivation for the obese to lose weight and improve their health.

It’s a booming market with considerable potential and Australia is home to some of the leading medical manufacturers. Electronics News spoke to some of these companies to find out how they see electronics and medicine combining in the future.  

Inside the body

The ongoing miniaturisation and improving power efficiency of electronics is encouraging the use of more implants says David Mulcahy, ResMed’s vice president of sleep product development. The smaller the device can be made, the less invasive it becomes for the patient, and long battery life reduces the number of inconvenient trips to hospital to swap out exhausted cells.

ResMed is a global leader in the development, manufacturing and marketing of innovative medical products for the treatment and management of respiratory disorders, with a focus on sleep-disordered breathing (SDB, also known as sleep apnea).

“[Implants] used to be the domain of life-critical applications in the past, but we expect to see more low cost, low complexity devices, in less critical applications, including simple passive sensors, that improve patient management and care,” Mulcahy told Electronics News.

If the work of Bionic Vision Australia is anything to go by, implants are indeed moving into less critical applications, but applications which still drastically improve patients’ quality of life.

The Bionic Vision Australia project aims to restore vision to people affected by retinitis pigmentosa and age-related macular degeneration, via use of a bionic eye implant.

The system is intended to capture footage via a camera attached a pair of eye glasses. The visual information would then be transmitted as RF signals to a chip actually in the eye, which then uses electrical impulses to stimulate the retinal ganglion cells which in turn connect to the optic nerve.

Professor Stan Skafidas is program leader for the development of this high-acuity device at Bionic Vision Australia. He is also the research group manager in embedded systems at National ICT Australia (NICTA), Australia’s ICT centre of excellence.

The high-acuity device program is currently developing the second prototype of the retinal implant, which provides higher resolution imaging, with 1000 stimulating electrodes, compared to the 100 electrodes of the first prototype.

The bionic eye is far from the only implant-related technology on the horizon. Prof. Skafidas points out that Australian researchers, be it at NICTA or elsewhere, are also working on bionic ears, deep brain stimulators which combat certain psychological conditions and implants to treat chronic pain by stimulating muscles and nerves.

But surely pain and psychological conditions can be treated by taking a tablet, without the need for invasive implants and surgery? Prof. Skafidas agrees, but explains that implants are much more precise in their effect.

“The body is very specialised, and you need to have the right level of chemical or pharmacological agents at the right location, at the right time. You can’t target where those drugs are going,” Prof. Skafidas told Electronics News. “[But] these new types of [implant] technologies…can be much more targeted for a very specific part of the brain.”

And, in the case of reversing vision loss, for example, pharmacological solutions don’t look like providing an answer, leaving the field open for implants.

But for all their promise, implants have one serious drawback: they are not biocompatible, so the body starts to attack what it perceives to be a foreign object. The attack comes in the form of an immune response that brings with it a risk of necrosis or histological changes around the site of the implant.

Diamonds, it turns out, are a patient’s best friend.

“In the bionic eye, we’re encapsulating devices in polycrystalline diamonds. Diamonds are very inert, structurally very strong,” said Dr. Skafidas, “There’s also a lot of work in developing new types of biocompatible materials.”

Power is the other big challenge for implants. Battery technology is moving slowly compared to other advances in electronics, and implants that run constantly are greedy power consumers.

Prof. Skafidas says technologies like supercapacitors or power harvesting may provide the answer. Wireless power transfers are also an option, although the low efficiency of this technology means a lot of the energy is dissipated in the tissue.

In the meantime, reducing the power consumption of the electronics by upping the efficiency will buy some time for either battery technology or new techniques to catch up.

Body area networks

Compact size and long battery life are not just desirable characteristics in implants; all electronics medical devices benefit from these attributes. The goal is to make devices so unobtrusive that they fit seamlessly into the normal lifestyles of patients. And this goal is never more important than with Body Area Networks (BANs).

BANs comprise a network of compact wireless sensors – boasting long battery life to minimise maintenance – monitoring vital signs such as pulse, blood pressure and blood glucose levels. The sensors can send their information to a variety of “gateways” such as mobile phones or PCs, and from there to remote physicians.

Electronics News spoke to Bert Gystelinckx, program manager of imec’s Human++ program, who is widely regarded as a thought leader in the BANs sector.

Headquartered in Leuven, Belgium. Imec performs research in nano-electronics, delivering technology solutions to the ICT, healthcare and energy sectors.

In particular, its business line Human++ works on innovative solutions in the healthcare domain. Within Human++, imec and Holst Centre develop technologies for wearable and implantable body area networks, with low-power components, radios and sensors.

The goal of monitoring, according Gystelinckx, is to improve quality of life. In current hospital technology, this involves wires and cables running from bulky machinery to a patient, who is consequently “tied” to a bed. BANs remove the wires, reinstating the patient’s independence.

Gystelinckx outlined three main areas using BANs that are occupying imec: cardiac monitoring, brain monitoring and emotion monitoring.

“In cardiac monitoring, we work on all kinds of wearable patch-like devices, which you can just stick on, that monitor full electrocardiograph (ECG) from one to multi-leads,” Gystelinckx said.

In brain activity monitoring, the organisation is developing new generations of electroencephalogram (EEG) headsets that monitor a range of conditions from sleep to epilepsy, with a focus on capturing a high integrity signals via devices that would be practical to use in daily life.

Emotion monitoring involves capturing skin response, respiration rate and heart activity, which combined with EEG allow insight into emotion. There is also ongoing work on sensors which detect biochemicals and chemical compounds found in breath.

“By [using the latest technology], you can take advantage of low power consumption,” explained Gystelinckx, “And because the electronics are so low-powered, with even a tiny battery, you can run these devices for a week or even up to months at a time.”

As with industrial networks, often the most power-hungry operation is transmitting data wirelessly. To address this, imec, Holst Centre and NXP announced the CoolBio ultra-low power biomedical signal processor in February 2011.

The new chip consumes only 13pJ/cycle when running a complex ECG algorithm at 1MHz and 0.4V operating voltage. It is designed to be integrated into the sensor nodes, so data is processed and compressed directly on the nodes, reducing the amount of data which needs to be transmitted wirelessly.

Standards and the exact transmission technologies for BANs are still being worked on, most notably by IEEE 802.15 Task Group 6, but there is widespread consensus that the resulting technologies and protocols would need to meet the relevant medical and communication regulations, as well as combine low power, reliability, quality of service, data rate and non-interference properties.

In the meantime, companies like imec are continuing to work on smaller and more efficient electronics. The hope is for interconnected healthcare and monitoring devices which are truly wearable and integrated into everyday objects like clothing, buttons and jewellery, allowing better autonomous and remote reliable health monitoring.

There’s an app for that

At the Wireless Health Conference, held recently in Sydney, a key discussion was the use of smartphones as a gateway from BANs (which use wireless sensors with a restricted range) to a wider network of doctors, patients, and equipment suppliers.

In his address to the conference, NICTA’s CEO David Skellern provided a clear vision of the future of healthcare offered by BANs.

“BAN is around-body wireless. It’s low power, it’s high speed, it’s always on, and it will be built into your phones,” Skellern said. “The aim of this is to remove every wire in the hospital, integrate all your personal monitoring devices and have the system function whether it’s at home, work or play.”

According to Gystelinckx, “the smartphone…is a central hub for all of these [BAN] devices. For example, we hooked the ECG monitor up to an Android-based cell phone,” Gystelinckx said, “indeed, the cell phone is probably going to be a key element in capturing, and relaying data that is coming in [from the BANs].”

With the rise of outcome-based medicine policies determining subsidies for healthcare equipment, companies like ResMed hope BANs, connected to the cloud via smartphones, will not only provide a convenient source of compliance information, but also help patients manage their own health.

“In the future, patient software for smartphones will become commonplace for information, diagnostics and treatment support,” said ResMed’s David Mulcahy. “The emergence of standards supporting home health and medical data transfer will increase the ability of patients to monitor their own health.”

The screen of the  smartphone could become a window for patients to “peer into their wellbeing”, helping them gain a better grasp of the situation, in the hope of helping them understand the treatment. This increased visibility is not just a “nice to have” feature, it can also have tangible benefits for patients, Mulcahy added.

“Viewing information about their condition and treatment may help remove some of that ‘fear of the unknown’ that patients may have had when confronted with a diagnosis they previously may not have understood,” he explained.

New models of care

The Wireless Health Conference in Sydney also featured Jan Janssen, senior vice president of design and development at Cochlear, a company that provides implants to combat hearing loss in children and adults.

According to Janssen, the company has already made notable headway in providing recipients of its implants with improved control and insight into the operation of their devices.

Most of the progress has been in the user interface found on the sound processor unit. The current generation of devices from Cochlear allows the user to control and monitor the system, with a bidirectional link to the implant.

Implant recipients can use their device to change the patterns and algorithms used by the microphones on-the-go, to optimise the device’s performance in different situations. These algorithms were once only adjustable by a specialist.

Janssen says Cochlear is looking to build on this advantage in the future.

“With the abundance of internet and mobile computing and wireless technologies, we can develop a new clinical model,” Janssen told the audience, “where the classical clinical model involved a highly specialised, typically academic clinic, we are now working on solutions that will move the care to satellite centres or to the recipient’s home.”

ResMed’s Mulcahy agrees a new paradigm of care is on the horizon.

“We are seeing a move towards decentralised (or distributed) health care versus the centralised hospital model,” Mulcahy said, “Patients want greater control over their own health care and data, which will be facilitated by technology enablers.”

Moving tasks like tuning and fitting down the skill ladder means patients will eventually be able to maintain their own treatment equipment and regimes within their own homes or working environments, without having to make regular trips to clinics.

The reduced workload means clinics and medical professional will be able to focus on new and more technically difficult cases, while still providing the occasional check-up and care for existing patients.

Such a move would also make treatments more affordable and available to a greater set of potential patients, especially in regions of the world where medical specialists are in short supply.

Slowly does it

Less invasive, more intelligent. Precisely targeted implants. Care without cables. More patient visibility and control of their own health conditions and outcomes. Better usage of professional resources. Electronics will make these healthcare providers’ dreams become reality.

But while increasing the use of electronic technology in medical care will yield many advantages, care must also be taken to mitigate the risks brought about by putting technology in such close proximity to the human body.

Circuits, for example, must be properly isolated from body tissue, and include measures to neutralise risks in the case of device failure. And in the face of continuing scientific furore over the effect of mobile phones on the human body, BAN technology needs to be developed and tested to minimise the risk of harm to the user.

Additionally, protocols for medical data transfer will need to be updated or created for the new network models, in order to provide security, privacy for the patient and efficient use of bandwidth.

The advances of healthcare and technology have been inextricably entwined for over five decades and this has proved to be good for the profession, patients and the economy. But future progress needs to be measured to allow regulation and certification to keep up. The last thing sick people need is for their current problems to be solved only to be replaced by a new set of unforetold challenges.

This article is an extended version of the piece which originally appeared in the April 2011 print issue of the Electronics News magazine.