Category Archives: General

In case you’ve just missed it…

Posted on 30/06/2011 by | Leave a comment

Fixing the Brain-Computer Interface

Researchers are addressing the sizable population for whom
BCI doesn’t work

By Erica
Westly  /  June 2011

New website (in Dutch): http://www.braininnovations.nl/

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It takes some cooking to prepare a good meal

Posted on 24/06/2011 by | Leave a comment

Frequent readers of this weblog may have started to wonder whether the activities of the Biomedical Electronics Group have gradually fainted and dissolved in eternity, its members have all become hobos and it all ended in a big dream. Bzinga. The truth is, of course, that everybody is very busy and under the yoke of some deadline or another.

Senad and June been working very hard on a first proof-of-principle of a Tinnitus detector circuit. Such a circuit should allow for detection of the spatial properties of tinnitus and give objective information on its severity. This could, in turn, lead to more refined or adjusted stimulation therapies. Don’t sell your mother for it, yet, but expectations are high. The findings will be worked out in a manuscript, to be submitted to the annual BioCAS Conference today.

On the detection side of things, Yongjia has been working very hard on the new type of level-crossing analog-to-digital converter, described in an earlier weblog. Also this work will be submitted to the BioCAS Conference.

Duan Zhao received the good news that our paper (together with the Holst Centre) on a reconfigurable subsampling receiver has been accepted for presentation and publication at the PIMRC Conference in Toronto. Congratulations. He just returned from a visit to his home country and we’re happy to have him back again.

Of course there is more that can be reported, such as the coming ELCA day trip, the preparations for organizing BioCAS 2013 in Delft, the IMDI NeuroControl, more power-efficient neurostimulation circuits, higher-efficiency RF energy harvesting circuits, June’s paper that got accepted in Transactions on Circuits and Systems-I: Regular Papers (congrats, too), Sandro’s and Senad’s paper that enjoyed the same fate (congrats, too), STW Perspectief and how the Dutch Ministries of Economical Affairs, Agriculture and Innovation and of Health, Wellbeing and Sport have no clue on how to increase valorization in the Netherlands (as witnessed yesterday at the MedTech West Event), but this would make good stuff for another blog. So stay tuned!

Wouter

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Mr. Brain: The Role of Neuroscience in Crime Investigation

Posted on 08/06/2011 by | 1 comment

More than a week ago, Wouter recommended a Dutch documentary ‘Mystery of the brain’. I believe that the documentary must be very interesting but unfortunately I don’t understand Dutch… What a pity.

I also would like to share my experience with you all in a way that is more relaxing. There is a Japanese TV series called “Mr. Brain” that we can watch online at http://www.youtube.com/watch?v=pKjHIIK7qew&feature=related.

After being busy with my research, watching it reminds me of myself and my work. It makes me smile sometimes. In these series, we will see how the detective and the neuroscientist deal with each other in a bitter-sweet-funny way. Understanding the brain helps a lot in interpreting the evidences that are left behind at the crime scene. Whenever the story goes to a complicated theory of neural processing there will be animations popping up to explain in a very cute way.

It is also good for kids, I think.

A few useful things I got from watching it:

  • I enjoy eating bananas more
  • I know where to sit in front of the girl I meet for the first time
  • Color comes first, shape follows but sound is the most powerful
  • We are using only 5% of our brain. There are still more than enough resources in our brain
  • For creativity, just don’t give up

Like Neil Yongjia said before singing: “I hope you’ll enjoy.”

June

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Smaller can be better

Posted on 07/06/2011 by | Leave a comment

After the 2011 edition of ELCA Music Festival, I was dragged (by some mysterious power) deep into the idea that came to my mind around three years ago. At that time, I was trying to simultaneously linearize and reduce a transconductance of a Gm cell (V–I converter circuit) for very low frequency biomedical filtering. The linearization and transconductance reduction were successful but the success came prices that I needed to pay:

  1. circuit complexity which is really unfriendly to weak inversion CMOS.
  2. more current consumption which was not surprising. It was very well in line with the circuit complexity. 
  3. more noise contribution (this was also a good friend with circuit complexity).

When I looked into the dynamic range of my design, it was not improved that much from that of an ordinary differential pair circuit (even so the paper was published [1] :). Then I got an idea that ‘instead of inventing a sophisticated linearization technique to obtain larger dynamic range, trying to use as less as possible noisy circuit elements and forget about linearization are more reasonable for biomedical signal processing which requires a good deal of power reduction’. The idea was left there since then for two reasons: I had other jobs to do and the idea seemed too sloppy.

Let me tell you more about the mysterious power. Several times we did rehearsals before the ELCA festival. I was in charge of acoustic guitar and harmonica for the song called ‘The end of the world’ http://www.youtube.com/watch?v=KmnKCE99sYE. Playing two instruments at the same time made me tired and it did not make a good harmony as expected. So I stopped playing the guitar and exercised only the harmonica (of course combined with the piano from Wouter, the electric guitar of Mark and Wannaya’s voice (I could not find this song on our Youtube channel — don’t know why). The song turned out better than before and this reminded me of that sloppy idea!!!

I did an investigation and found that there are strong evidences supporting my idea founded in low-pass filter design [2] [3]… It works!!! Large dynamic range was achieved as well as a very good figure of merit. Although the above filters were dedicated to communication systems rather than for low frequency biomedical signals, the underlying concept of the filter should be applicable for biomedical signal as well. Only a bit more effort was needed to work it out.

Good news!!! Recently, with the help from Senad, who has become 22 years old today — the same as me :). Happy Birthday!!!— my sloppy idea was realized. A 6th-order ECG low-pass filter with a large dynamic range of 59dB and extremely low power consumption of 0.45nW has been designed. We plan to submit this work to BioCAS2011. Hopefully, the reviewers will like it, too.

More good news!!! The application is not limited to low-pass filters only. I’m developing this idea further to apply it for a cochlear channel band-pass filter. What I can say now from the circuit simulations is that the filter provides the best figure of merit compared to state of the art designs. The secret is that all terminals of a single MOSFET device are being used, one pole and one zero are achieved by only two transistors sharing the same bias current.

Next time, I will tell you more about this. Stay tuned if you are interested!!!

Healthy Haring is coming. I heard from Marijn that this year, since the weather is warm, the fish is growing bigger. See you in the Pub this coming Thursday for Harings and Beers 😀

June

[1] C. Sawigun, D. Pal and A. Demosthenous, “A wide linear range transconductor subthreshold transconductor for sub-Hz filtering,” Proc. IEEE ISCAS, pp.1567-1570, 2010

[2] D. Python, A. S. Porret and C. Enz, “A 1V 5th-order Bessel filter dedicated to digital standard proceses,” Proc. IEEE CICC, pp. 505-508, 1999

[3] S. D’Amico, M. Conta and A. Baschirotto, “A 4.1mW 10MHz fourth-order source-follower-based continuous-time filter with 79-dB DR,” IEEE J. Solid-State Circuits, pp. 2713-2719, Dec. 2006

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Posted in Electronics, General, Pacemakers

BME Youtube Channel

Posted on 30/05/2011 by | Leave a comment

Only three months ago the Biomedical Electronics Group started this weblog to give the world a glimpse of what we are doing. More than 30 blogs have been written so far on our daily thoughts and projects and we’re still going strong! 

Today, we created our own "BMETUDelft" youtube channel!! The first few videos have already been posted. Here an impression of the atmosphere during the ELCA festival 2011 while the ELCA band plays Drunken Lullabies!!

http://youtu.be/18jmQCklfog

This youtube channel will also be used to explain our research areas. This short animation movie explains the concept of the Smart Implantable Neuro-Stimulator that we are developing:

http://youtu.be/UX56ibySb3I

So check out our youtube channel named BMETUDelft. We will soon post more videos, so stay tuned!!

Mark

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Dutch documentary on the Mystery of the Brain (6 episodes)

Posted on 28/05/2011 by | Leave a comment

BreingeheimLast Tuesday I saw an excerpt of an interesting episode on Dutch television about what happens with the human brain when it ages and in particular what happens with it in the unfortunate situation of Alzheimer’s disease. This episode, presented by the well-known and charming Dutch news presenter Charles Groenhuijsen, in fact is part of a larger series that tries to shed some light on what happens in this 1.5kg human organ that is at the base of all our thoughts, actions, emotions, etc., of which its intricacies and inner workings are still a mystery to us. 

The complete series (in Dutch) can be viewed from Uitzending Gemist and also from the following link of Omroep Max: http://www.maxbreingeheim.nl.

Highly recommended!

Wouter

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Posted in General, Understanding the Brain

“And the paralyzed will walk again”

Posted on 22/05/2011 by | 2 comments

With this promising statement of Michio Kaku ends a video cut that I made from a TV documentary entitled "2057 The Body" and which I use inside a presentation on wearable and implantable medical devices. The documentary predicts that in the year 2057 we will be able to inject tiny wireless sensors and actuators inside the body thereby restoring the connectivity of the peripheral nervous system and be able to use our senses and control our muscles again.

Last week, still 46 years away from the year 2057, it was reported in the Lancet that [from the UCLA Newsroom] "a team of scientists at the University of Louisville, UCLA and the
California Institute of Technology has achieved a significant breakthrough in
its initial work with a paralyzed male volunteer at Louisville’s Frazier Rehab
Institute — the result of 30 years of research to find potential clinical
therapies for paralysis.

The man, Rob Summers, 25, was completely paralyzed below the chest after
being struck by a vehicle in a hit-and-run accident in July 2006. Today, he is
able to reach a standing position, supplying the muscular push himself. He can
remain standing, and bearing weight, for up to four minutes at a time (up to an
hour with periodic assistance when he weakens). Aided by a harness support and
some therapist assistance, he can make repeated stepping motions on a treadmill.
He can also voluntarily move his toes, ankles, knees and hips on command.
 
These unprecedented results were achieved through continual direct
"epidural electrical stimulation" of the subject’s lower spinal cord, mimicking
signals the brain normally transmits to initiate movement. Once that signal is
given, the research shows, the spinal cord’s own neural network, combined with
the sensory input derived from the legs to the spinal cord, is able to direct
the muscle and joint movements required to stand and step with assistance on a
treadmill.
 
The other crucial component of the research was an extensive regime of
locomotor training while the spinal cord was being stimulated and the man
suspended over the treadmill. Assisted by rehabilitation specialists, the man’s
spinal cord neural networks were retrained to produce the muscle movements
necessary to stand and to take assisted steps.

[…]

Relief from secondary complications of complete spinal cord injury —
including impairment or loss of bladder control, sphincter control and sexual
response — could prove to be even more significant.
 
"The spinal cord is smart," said Edgerton, distinguished professor of
integrative biology and physiology and of neurobiology at UCLA. "The neural
networks in the lumbosacral spinal cord are capable of initiating full
weight-bearing and relatively coordinated stepping without any input from the
brain. This is possible, in part, due to information that is sent back from the
legs directly to the spinal cord."
 
This sensory feedback from the feet and legs to the spinal cord facilitates
the individual’s potential to balance and step over a range of speeds,
directions and levels of weight-bearing. The spinal cord can independently
interpret these data and send movement instructions back to the legs — all
without cortical involvement.

[…]

More than 5 million Americans live with some form of paralysis, defined as
a central nervous system disorder resulting in difficulty or inability to move
the upper or lower extremities. Roughly 1.3 million are spinal cord injured, and
of those, many are completely paralyzed in the lower extremities.
 
Epidural stimulation, in the context of paralysis of the lower extremities,
is the application of continuous electrical current, at varying frequencies and
intensities, to specific locations on the lumbosacral spinal cord corresponding
to the dense neural bundles that largely control movement of the hips, knees,
ankles and toes. The electrodes required for this stimulation were implanted at
University of Louisville Hospital by Dr. Jonathan Hodes, chairman of the
department of neurosurgery at the University of Louisville.

[…]
 
For a more in-depth discussion of the research behind the breakthrough,
watch this interview with
Edgerton." 

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Posted in General, Neurostimulation and Neuromodulation

Running for brains!

Posted on 21/05/2011 by | Leave a comment

On June 2 (Hemelvaartdag) we go with seven people (you are right, one is missing on the picture) of TU Delft (BHV members and Gerard Meijer) to the Golden Ten Loop in Delft to run 10 kilometers for “De hersenstichting”, a charity foundation stimulating brain research and educating the public about it.
As three of us had problems with our brain (one had a stroke, one had another brain problem and I had a complete brain check-up for my undefined kind of hyperventilation) it was a brainwave to run for this good cause.
“De hersenstichting” takes care of a lot of research in all kind of brain damages, so therefore we ask you to be a sponsor of our running event. You can give cash money to Marion or send it to bank account 3532534 t.n.v. N.J.M. van Zon and mention "Golden Ten Loop – hersenstichting".  In both cases you will sponsor the whole group.
The orange shirts are from the hersenstichting and the health coach of the TU Delft sponsored the printing of the shirts with a TU Delft logo. Please be so kind to donate a small amount for this running event and maybe you can also be a supporter on June 2 at the start and finish place on the Burgwal in Delft. It will be a nice afternoon with a lot of people and a lot of music.
Marion 
 

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STW project ReaSONS approved!

Posted on 20/05/2011 by | 2 comments

Today I received some good news by means of a phone call of Wouter Segeth, program officer with STW, the Dutch Technology Foundation. Our ReaSONS project (Realtime Sensing of Neural Signals), a collaboration between Delft University of Technology and Leiden University Medical Center has been approved.

The project aims at the realtime recording of the evoked compound action potential (ECAP) generated by the haircells in the cochlea while fitting a cochlear implant. Also it is considered to be one step towards the creation of realtime online closed-loop neurostimulators.

This is of course good news for Cees-Jeroen, upcoming PhD student in the BME group, who supposedly will start his duties in September this year. 

Wouter

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User permissions changed

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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