Depiction of an implant in a human arm
© Wilddesign GmbH, Gelsenkirchen
2023-10-01 VDE dialog

Medical implants: Wireless networking

Microelectronic implants are fitted permanently in the human body to treat the illnesses of millions of people via nerve stimulation. To improve patient care even further, researchers are working on digitalizing and connecting implants.

By Julian Hörndlein

VDE dialog - the technology magazine
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Es nervt! Viele kennen den Tinnitus als leidvolles Geräusch in den Ohren. Weltweit sind laut italienischen Forschern 740 Millionen Menschen betroffen. Für knapp 118 Millionen von ihnen ist das Dauerpiepen eine nicht aushaltbare Belastung. Therapien mittels externer Technologie gibt es schon. Dabei wird der Hörnerv bei gleichzeitiger elektrischer Stimulation der Zunge über ein Mundstück gereizt. Eine wirkungsvolle Alternative soll künftig das Einsetzen von aktiven Implantaten ins Innenohr sein. Ohne von außen sichtbar zu sein, soll das

Is there anything more annoying? Tinnitus – the distressing sensation of phantom noise in the ears – is an affliction familiar to many. Italian researchers estimate that it affects 740 million people worldwide. For almost 118 million of them, the constant ringing reaches intolerable levels. Therapies using external technologies are already available: One solution involves activating the auditory nerve by electrically stimulating the tongue using a small device in the mouth. Scientists are also working on active implants for the inner ear as an effective future alternative. Invisible from outside, these devices will stimulate an area of the inner ear known as the round window and soothe the phantom sounds typical of tinnitus. Modern medicine is almost unimaginable without microelectronic implants in the human body. Just as pacemakers extend life and cochlear prostheses allow people to hear again, the new technological therapy for tinnitus could considerably improve the lives of millions of people, says Roman Ruff, a scientist at the Fraunhofer Institute for Biomedical Engineering IBMT. “Tinnitus is a common problem,” he adds.

Until now, medical implants have usually involved sensors and actuators that are distributed around the body and connected to a central implant by cable. It’s an effective solution. “The cable connection is often the part of the implant that fails first, however,” Ruff reveals. And when an implant fails, the cabling complicates the intervention needed to fix it. Scientists have now developed technology to address this flaw. “We’ve taken the step from a single central implant to a network of miniaturized implants,” Ruff reports. His institute was part of the Federal Ministry of Education and Research’s INTAKT innovation cluster, which was set up to work on interactive microimplants and research ways for them to connect and communicate with each other. “In tangible terms, we developed a technology platform,” says Ruff. Developing connected implants is challenging: the chips need to be enclosed in a capsule so that they don't interact with the body in undesired ways. Data transmission and signal analysis also need to be flawless throughout the lifespan of the device.

Depiction of the different layers of a microimplant

Complex functionality in the smallest of spaces: the microimplant is contained in a capsule and has an eight-layer circuit board.

| © Wilddesign GmbH, Gelsenkirchen

Prof. Dr. Thomas Stieglitz, professor of biomedical microtechnology at the University of Freiburg and head of the VDE DGBMT expert committee on neuroprosthetics and intelligent implants, points to another research trend in medical implants. He and his team have been working on intelligent prostheses and implants as part of the INOPRO project, a sister project of INTAKT. “We use familiar technologies for new applications,” Stieglitz explains. For example, they have developed deep brain stimulation to help patients with Parkinson’s disease. Contact points are implanted in the brain to monitor the course of the disease. In addition to Parkinson's disease, deep brain stimulation can be used to treat severe psychiatric diseases. According to Stieglitz, studies are currently underway in Europe to approve it for the treatment of depression. He also believes electrical stimulation has the potential to replace medication. “We're targeting lifestyle diseases such as hypertension and diabetes, but also diseases like Crohn’s, COPD or rheumatoid arthritis,” says Stieglitz – particularly when patients don’t respond well to medication.

Once the implants have been correctly positioned in the body, the next step is to get them communicating with each other. “If I have a vagus nerve stimulator, a prosthetic knee and a pacemaker, it’s helpful for each device to know what the others are doing,” says Stieglitz. “The trend is certainly toward more integration,” agrees Prof. Dr. med. Thomas Lenarz, deputy chairman of VDE DGBMT and a professor at Hanover Medical School. His research focuses on hearing impairments and implants. The cochlear implants he regularly uses are now “entirely digital systems that rely on connectivity.” They can communicate with each other and with hearing aids, as he explains in our detailed interview (see box). Connecting them to other types of implants is the next item on the agenda.

Implants exchange data – securely

An unavoidable implication of this connectivity is that the implants all need to store data in the same place. Using its platform, the INTAKT consortium has already realized technologies to enable this. “There are radio frequency bands that are approved for use in implants,” says Roman Ruff from Fraunhofer IBMT. These are supplemented by infrared communication, particularly for implants close to the skin. Of course, one aspect that has to be considered when implants exchange information is data security. As part of the EU project AI4HealthSec, Fraunhofer IBMT is currently working on a software platform that guards against cyber attacks in healthcare and has proposed connected active implants as a use case. However, Ruff believes there is not much risk of malicious bystanders being able to interfere with people’s active implants. “The implants and system components outside the body have a very short range, so it would be very difficult to compromise these systems using near-field communication,” he points out.

While both scientists emphasize that the development of connected implants is very much still at the research stage and not ready for the market, they are convinced that the technology will help many people in future. Stieglitz: “Getting the implants to talk to each other is a transformational discipline.”

Julian Hörndlein is a technology journalist in Nuremberg.

Cochlear: From inner-ear microphones to Bluetooth-enabled nerve implants

adimas /
2023-10-01 VDE dialog

They’re one of the best-known and most-researched implants used in medical practice: cochlear implants, which enable people to hear again. Developed and trialled in the 1960s, the technology behind them has steadily improved over the years. Now digitalization and connectivity are on the agenda. We recently spoke with top researcher Prof. Dr. Thomas Lenarz, professor at Hanover Medical School and board member of the German Society for Biomedical Engineering (DGBMT) within VDE.

Interview: Julian Hörndlein

Read more