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Posted on 20/05/2011 by | Leave a comment

The regular contributors to this blog have received a free upgrade. By becoming a Publisher rather than a Contributor, I hope we will be able to serve the readership in a more timely manner. Check it …

(W)out

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Posted in General

Brain and ears…

Posted on 20/05/2011 by | Leave a comment

Usually this blog reports on fancy inventions or breakthroughs related to the biomedical field. We have discussed many technical advances that will ultimately improve the quality of people who suffer from a wide range of pathologies.

Sometimes though medical knowledge and engineering can come together in a funny way, too. The company ‘neurowear’ is doing exactly this as stated on their website: "to develop fashion items and gadgets using brain waves and other biosensors". Their first product is called ‘Necomimi’ and instead of spending a lot of words explaining what it exactly does, this movie might be self-explaining:

http://www.youtube.com/watch?v=w06zvM2x_lw

Enjoy!

Marijn

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Posted in Brain-Machine Interfaces

Unexpected Meet and Greet with Hero in Circuit Theory

Posted on 08/05/2011 by | Leave a comment

Georg Simon OhmLast week, I was in Köln, Koeln, Keulen or Cologne (depending on from which country you are) with my family and while on our way to the Dom, Cologne’s well-known cathedral, I bumped into one of the greatest heroes of electric circuit theory: Georg Simon Ohm. The sign says that "George Simon Ohm discovered, in this house, being a teacher at the Old Gymnasium in Cologne, in 1826, the foundation of electric current."

Though one of the most important discoveries indeed, I think it is not so much the discovery of the foundation of electric current, but rather the relation between voltage and current that holds for linear resistances (and impedances, in the harmonic regime), later known as "Ohm’s Law" that caused his name to be remembered forever.

For those that have both an interest in technology and law, I cordially recommend Ohm’s Law and Kirchhoff’s Laws as basic study material.

Wouter

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Posted in Education, Electronics, General

First clinical tests!

Posted on 03/05/2011 by | 1 comment

 

Last friday a milestone was reached in the Biomedical Electronics Group: the first clinical experiments were conducted with the neurostimulator ‘uStim’ designed within the group! This neurostimulator allows the use of arbritrary waveforms for neural stimulation while still assuring safe stimulation by charge cancellation. After extensive electrical characterization of the device in the last couple of months the moment was finally there to test it in real life!

Two subjects were implanted with percutaneous leads. These leads were connected to the stimulator while the EEG activity of the subjects was closely monitored. The subjects were first stimulated using a commercially available stimulator (ANS – St. Jude Medical) and after that using the uStim. 

The first prelimenary results are promising. Both subjects showed clear responses in the EEG as a result of the stimulation pulses generated by our stimulator. The data will need further analysis in order to compare it to the commercially available stimulators, but at least it is possible to conclude that the stimulator is able to generate arbritrary stimulation pulses in a safe manner.

It was a great moment for the researchers to see their work in real action! We are looking forward to working on the next version of uStim!

Marijn

 

Preparing the electronics: 

 

 

Connecting the leads!!

 

 

EEG monitoring showing the response to the stimulator: 

 

All activity is closely monitored. 

 

 

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Posted in Neurostimulation and Neuromodulation

Can I ask a question?

Posted on 22/04/2011 by | 2 comments
There was a very interesting lecture from dr. Firat Yazicioglu yesterday. This lecture, entitled Analog Signal Processing for Bio-Medical Applications, was at IMEC Belgium in Leuven. However, Biomedical Group members attended the lecture online, using streaming technology. The lecture was real-time projected in the Davidsezaal at the 18th floor of our building at Delft University of Technology (TU Delft). As I really enjoyed the lecture, I would like to share a few main points with you.

Dr. Yazicioglu introduced the lecture by explaining what main drivers are behind emerging biomedical electronics. One of the most important drivers is that healthcare costs can be reduced by remote monitoring of the patients. Other important drivers are the need for tools for emerging therapies, need for smart (closed-loop) devices that can adapt their therapy to the patient’s condition, understanding of biology and brain communications and Brain Computer Interfaces (BCI) for, i.e., the gaming industry.   

The speaker continued the lecture with topics about instrumentation amplifiers, impedance measurements and biomedical signal processing.  

One of the main messages of instrumentation amplifiers part is that implantable and wearable biomedical devices tighten the specifications of traditional instrumentations amplifiers where an optimum between noise and power consumption has to be found. In the biomedical electronics field, instrumentation amplifier specifications are much tougher and an optimum among noise, supply voltage, # of extern components, CMRR, input impedance and DC filtering range needs to be found.

Other types of electronic circuits treated by the speaker were circuits for impedance measurements. Such measurements can be useful in electrode quality check, motion artifact monitoring, medical imaging, respiration monitoring and impedance cardiography. 

Last part of the lecture was about biomedical signal processing. In biomedical signal processing, very often, there is a need for high count channel measurements. Employing traditional signal processing schemes it is impossible to keep biomedical devices power efficient. However, by combining Analog Signal Processing (ASP) and Digital Signal Processing (DSP), more power efficient medical devices can be developed. Important massage here was that in the case of careful design the total power consumption of the system can be less than the sum of the power consumptions of all separate blocks,
Psystem << Panalog+Pdigital+Pradio.
I would like to end this post by thanking dr. Firat Yazicioglu for a very interesting and useful lecture.

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Posted in Education, General

Making music keeps the brain fitter

Posted on 22/04/2011 by | Leave a comment

On http://esthenews.org/tag/brenda-hanna-pladdy/ we can read the following:

"The Tiger Mothers were right all along: Music lessons as a kid may make you a sharper grown-up.

A new study finds that older adults with musical experience perform better on some cognitive tests than those who had never studied music. With only 70 participants, the study was small, but the results match those from other studies of challenging tasks, including findings that learning a second language protects against dementia.

no music no life"Musical activity throughout life may serve as a challenging cognitive exercise, making your brain fitter and more capable of accommodating the challenges of aging," study researcher Brenda Hanna-Pladdy, a neurologist at the Emory University School of Medicine, said in a statement. "Since studying an instrument requires years of practice and learning, it may create alternate connections in the brain that could compensate for cognitive declines as we get older."

[…]

"Whether the participant continued to play music into old age didn’t matter, the researchers found. Instead, long-term study in youth seemed to confer benefits far down the road."

The entire scientific article can be found at: http://www.apa.org/pubs/journals/releases/neu-25-3-378.pdf.

This is, of course, good news for those involved in the ELCA Music Festival, all of them who speak a second language (often English) and took up making music in their childhood, or, like Senad, inspired by the ELCA Festival, are currently taking up music lessons. Gradually I start looking out for the next edition…

Wouter

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Posted in General, Understanding the Brain

Programmable Implants

Posted on 21/04/2011 by | 2 comments

This article originally appeared in Delta, April 13, 2011. By Thomas van Dijk

For his PhD research, Dr Christos Strydis rethought the architecture for processors in biomedical implants.

In future implants might be recharged by the brain. (Photo: Ana Laura Santos)

Saying that they are committed to their research into neurostimulation is an understatement. In their quest to develop a treatment for patients with tinnitus, a syndrome where people hear phantom noises, Professor Dirk De Ridder, a neurosurgeon and neuroscientist at  University Hospital Antwerp, and assistant professor Eddy van der Velden, a medical researcher at Antwerp’s Monica hospital, are about to be operated on themselves. During an experiment to be held at the end of this month, the professors will have wires sticking out of the back of their heads, through which electrical pulses will travel to their brains. 

“They are really crazy,” says computer engineer, Dr Christos Strydis, laughing. In his office, Dr Strydis shows an application on his smart phone. With this app he will command the device – which is the size of a packet of cigarettes – that is attached to the guinea pig professors and generates the pulses. Depending on the frequency of the pulses, the test subjects might feel energetic, euphoric or sleepy, to name but a few of the possible states. 

Strydis is part of a large team of researchers from the faculties of Electrical Engineering, Mathematics and Computer Science, and Applied Sciences, who over the years have been working with the Belgian medics on biomedical implants. The team’s goal is to develop tiny, low-energy consuming implants that can be controlled by software, rather than being based solely on hardwired circuits. 

Strydis has been focusing on the type of processor needed for such devices. Last month he defended his PhD thesis, titled ‘Universal processor architecture for biomedical implants.’

Strydis believes that it’s time for a paradigm shift in the field of biomedical implants: “One big problem is that the electrical signals created by implants no longer aid patients with neurological diseases after a certain period of time, because the body simply gets used to the signals and ignores them. So the device should be smarter and more flexible. You should be able to programme it. What’s more, every patient is different, so standard implants with standard signals do not work optimally for everyone.”

It will take at least another five years before the device built by the Delft researchers will be miniaturised enough to be placed directly under the skull of patients, Strydis surmises. Neuroscientist Prof. van der Velden hopes that the battery inside the implant, which ultimately must work at a voltage of no more than half a millivolt, will be recharged by the brain. 

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Posted in General, Neurostimulation and Neuromodulation, Understanding the Brain

About impact factor, freedom trails and electrology

Posted on 11/04/2011 by | 1 comment

Dear reader,

Though I have tried to be virtually present as much as possible, I am currently neither in Delft nor in my hometown Leiden. This also explains the late hour of this post. Where I am, it is currently a little over 6 pm. I am in Medford, a small forensic town near Boston, MA, USA. The main reason for being here is twofold. First, as Editor-in-Chief (EiC) of the IEEE Transactions on Circuits and Systems-I, I participated in the annual IEEE Panel of Editors (PoE) meeting. Second, I am here to give an invited talk at Tufts University in a seminar hosted by Prof. Sameer Sonkusale.

During the PoE meeting, we discussed a lot about good and not-so-good EiC practices, about upcoming changes to IEEE Xplore, about plagiarism (which, unfortunately, becomes more of a problem), about journal performance metrics, etc. The latter is also very important to you. That is, if you (plan to) make scientific, design and engineering contributions and you (plan to) present them in a journal or at a conference. And if they contribute to your reputation as a researcher, scientist, designer or scholar. For this, our busy chairs, heads and leaders, more and more resort to the only thing they understand about your work, being "the number"; more specifically, the Impact Factor (IF). I will not bother you with the exact definition of IF; many people do not even know and don’t care, your boss probably included, but it is generally considered to be a measure to express your importance, or the importance of your publications, or the importance of the journal that you publish your work in. Whereas it purely counts incoming citations without considering the significance of those citations.

ethicsSince the algorithm for computing the impact factor is simple, it is also simple to manipulate. And this is exactly what is being done constantly, by authors, who for this reason include a lot of self-citations in their manuscripts, and by journals that impose a lot of self-citations (to the journal) on their authors. Since this is seriously blurring the reputation of people and journals, but also the minds of our evaluators, more objective figures-of-merit have been discussed, the most elegant one probably being the Article Influence. If you are interested you may wish to (and if you are a boss of a scholar or a scholar yourself, you probably should) check out http://www.eigenfactor.org/.

After the PoE meeting, I took off for a walk in and around the city center of Boston, called The Freedom Trail. See http://www.thefreedomtrail.org/. The Freedom Trail was recommended to me by Menno (as of now honorary member of the BME group) and, according to the web site, is "a 2.5 mile red-brick walking trail that leads you to 16 nationally significant historic sites, every one an authentic American treasure." And indeed it did. And I believe it also guides you through some of the most beautiful places in Boston. If you ever happen to be around, check it (and the Guinness from one of the Irish pubs) out!

Today I changed hotels and I am currently in Medford, where I will be staying for the coming two days, as tomorrow and the day thereafter I will meet various students, professors, heads and deans of Tufts University and give two presentations on Electronics for Wearable and Implantable Medical Devices, discuss possible opportunities for collaboration and discuss some latest research results that both Sameer Sonkusale’s group and the one of yours truly are working on.

So what about electrology, then? Well, today I went for a walk in the town of Medford and I came across a sign that advertises the services offered on 82 Forest St. Among them those of an Electrologist. So what does he or she do? Well, the sign reads on with the name of the therapist (which I will not disclose here) and the name of his shop: "Hair it go’s!" The service? Permanent Hair Removal. So if you ever wonder whether I may be getting bold, don’t you dare. Signing off with a famous phrase of Senad: "The things we do for science…."

Wouter

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Posted in General

Thoughts over an exam…

Posted on 08/04/2011 by | 1 comment

Besides many research related posts on this weblog, there is another important aspect in universities: education. Currently the spring examinations take place. It is time to see if our efforts in introducing the students into the exciting world of transistors were good enough. Today I was supervising a retake of a first year BSc-course. In order not to get too bored, I printed out a bunch of papers to read through…

Despite the reading material, I was preparing for a long morning. But nothing could be further from the truth! While the students were sweating and battling their way through the exam, I picked up a paper about the history of electrical stimulation [1]. It was discussing about the very first steps of electricity for medical applications. As it turns out, soon after the development of the first electrical devices in the second half of the 18th century (such as static electricity machines, the Leyden jar or later the volta-cell), these devices were put in use for medical research very soon. Just like myself today, people were fascinated by how our body responds to electricity.

It is incredible to read what achievements were made with the extremely limited equipment that was available. Even more incredible were the experiments that were carried out: the effect of electricity on the human body was demonstrated using the decaptivated heads of executed criminals! Furthermore the functionality of pacemakers was demontrated by over-anesthesthetized animals until cardiac arrest occured, to subsequently reanimate them using electrical stimulation. Remarkably the method was also applied to a human subject, but without success…

Besides experiments, the inguinity of researchers to build machines is very remarkable. Without the availability of vacuum tubes (let alone transistors), it is hard to make pulses with accurate duration in the order to hundred milliseconds (which are required for stimulation). Various mechanical systems are described, of which the most remarkable one is a system in which a gun is fired to cut two wires placed at a certain distance from each other. Only during the time the bullet is travelling from the first wire to the second, the system is injecting electrical energy into the tissue. Imagine how being a researcher was like in those days: shooting rifles the whole day! Quite a difference from running circuit simulations like we do today!

For more interesting stories I can highly recommend to read this paper. Or save it for when you have to supervise an exam. For now: time to check the exam!

Marijn

[1] Geddes, L.A., "The first stimulators-reviewing the history of electrical stimulation and the devices crucial to its development", Engineering in Medicine and Biology Magazine, IEEE , vol.13, no.4, pp.532-542, Aug/Sep 1994

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Posted in Education, General, Neurostimulation and Neuromodulation, Pacemakers

Slides Hermes Partnership Workshop “Visions Towards ICT Supported Health” have been posted

Posted on 07/04/2011 by | Leave a comment

HermesStill in shock by the post below? Don’t be. As always there’s hope on the horizon. The slides of the Hermes Partnership Workshop "Visions Towards ICT Supported Health" of last week have been posted online. If you want to find out more about one or more of the topics below, don’t hesitate to click here or on the links below.

“E-health in practice, business opportunities”, prof. dr. Felix Hampe, University of Koblenz, Germany

“Present experiences and future perspectives of Telerehabilitation”, prof. dr. ir. Hermie Hermens, University of Twente, The Netherlands

"Moving diagnostic, monitoring and therapeutic wireless medical devices into the homes and into the body",  dr. ir. Wouter Serdijn, Delft University of Technology

"Nanoscale smart communication components and systems”, a research proposal of Hermes partners, dr. Jean Benoit Pierrot, CEA LETI France  

"Status e-health and  telehealth in Poland”, prof. dr. Łukasz Januszkiewicz, University of Lodz, Poland

"e-health systems developments and business opportunities at SME-companies”, dr.ir. Piet Verhoeve, Televic, Belgium

"Energy harvesting in e-health applications”, dr. Paul Mitcheson, Imperial College, UK

Wouter

 

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Posted in General, Medical Body Area Networks