TU Delft to combat Parkinson’s disease and epilepsy with neurostimulator

Posted on 24/09/2011 by | 1 comment

23 September 2011 by Webredactie

In the future people with brain disorders such as Parkinson’s disease, epilepsy and tinnitus (ringing in the ears) may be fitted with a smart, miniaturised neurostimulator. This stimulator, a prototype of which was recently developed and tested by TU Delft, may considerably reduce the symptoms for some patients. An article on this can be read in the latest edition of Delft Outlook, the TU Delft science magazine, published online today.

Mobile phone

‘A great deal of how we function is determined by electrical currents in our body’, says electrical engineer Marijn van Dongen of TU Delft. ‘We can use this to tackle a whole host of disorders, such as Parkinson’s disease, tinnitus and epilepsy, at a local level. Yet at the same time, this technology is still somewhat “medieval”. At present the neurostimulator is a device the size of a mobile phone which is implanted in the chest. It sends electric pulses via a cable to electrodes in the areas of the brain which show abnormal activity. The electric cables which run through the neck to the brain can break and cause infections. They also lead to the formation of scar tissue in the neck.

SINs

The current design of the neurostimulator is not conducive to further miniaturisation. In order to obviate the need for cables, a complete rethink of the design is needed. Van Dongen is working on this with a large number of colleagues from various knowledge institutes and hospitals, as part of the Smart Implantable Neurostimulators (SINs) programme that started in 2008. In that year, brain surgeons Dirk de Ridder and Eddy van der Velden of Antwerp University Hospital (UZA) contacted electrical engineer Wouter Serdijn of TU Delft. Serdijn is the SINs programme leader. They aim to have developed a cranial-implantable neurostimulator within the next ten years: a two-millimetre thick device measuring two square centimetres including the battery and antenna.

More natural
Challenges facing the researchers in reaching this goal include integrating all the separate components in a single chip, and doing away with the space-consuming capacitors. ‘The stimulators also need to be able to automatically detect when they need to generate pulses, by analysing signals in the brain, just as a pacemaker does in the heart’, says Serdijn. ‘Furthermore, the pattern of the pulses needs to be adjustable and have a more natural form.

Prototype

The TU Delft researchers have already developed and recently tested a prototype. ‘This was a preliminary test to see if our neurostimulator was in fact capable of generating a suitable neural response’, says Van Dongen. It turned out that it was, and the prototype will be further miniaturised in the coming years.For this study Dirk de Ridder and Eddy van der Velden tested the device on themselves: they had temporary electrodes implanted in their body and were able to control the stimulator via an iPhone app.

More information

The latest edition of Delft Outlook, TU Delft’s science magazine, to be published online on 23 September and in print on 26 September, will feature an extensive article on the research conducted by Marijn van Dongen and Wouter Serdijn.

Contact information

Marijn van Dongen (researcher), M.N.vanDongen@remove-this.tudelft.nl tel +31 (0)15-2783679
Dr Wouter Serdijn (SINs programme leader), W.A.Serdijn@remove-this.tudelft.nl tel +31 (0)15-2781715
Nienke van Bemmel (science information officer), n.vanbemmel@remove-this.tudelft.nl +31 (0)15-2784259

Links:
http://www.delftintegraal.tudelft.nl
http://www.braininnovations.nl

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Posted in Electronics, General, Neurostimulation and Neuromodulation, Understanding the Brain

Electrical Stimulation of Brain Boosts Birth of New Cells

Posted on 23/09/2011 by | Leave a comment

ScienceDaily (Sep. 22, 2011) — Stimulating a
specific region of the brain leads to the production of new brain cells that
enhance memory, according to an animal study in the September 21 issue of
The Journal of Neuroscience. The findings show how deep brain
stimulation (DBS) — a clinical intervention that delivers electrical pulses to
targeted areas of the brain — may work to improve cognition. Read more.

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Posted in General, Neurostimulation and Neuromodulation, Understanding the Brain

Hot Wavelets

Posted on 09/09/2011 by | Leave a comment
The paper "Emerging Applications of Wavelet: a review", by Akansu, Serdijn and Selesnick has been declared the hottest (No. 1) paper in Computer Science, Physical Communication (Elsevier) over the period from October 2009 to September 2010. Over the past 9 months, the paper held its No. 1 position firmly, so it is thus heading for becoming the hottest paper for two consecutive years!

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Posted in Education, General

ELCA Festival, 2012 Edition will be on Friday, January 13

Posted on 08/09/2011 by | Leave a comment

PSSST! Mark your calendar!

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I’m back!

Posted on 08/09/2011 by | 2 comments

After one year of absence since I graduated for my master thesis, I can happily tell you that I’ m back :). On September 1 I started my PhD research on neural readout circuitry in cochlear implants.

The project is a collaboration between Delft University of Technology and Leiden University Medical Center and is funded by STW (Dutch Technology Foundation). It is called ReaSONS (Realtime Sensing of Neural Signals). Within this project we aim to develop new technology to record the evoked Compound Action Potential (eCAP) generated by the hair cells in the cochlea.

As soon as I have my first results I will let you know. Stay tuned!

Cees-Jeroen

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Posted in General

Transcutaneous Vestibular Stimulator

Posted on 26/08/2011 by | 1 comment

Vestibular stimulators stimulate the vestibular organ (located in the ‘labyrinth of the inner ear’) and can therefore have a direct effect on the balance of a person. Triggered by some movies that show the impressive and funny effects that Vestibular Stimulators can offer, our group decided to build a very simple stimulator to experience the effects ourselves. We also have been informed that there might be interest for this type of stimulators for medical experiments, so there’s more behind it than just fun.

Transcutaneous Vestibular Stimulation uses electrodes that are put behind the ear of the subject (being ourselves in our experiments) and a current is injected. We decided to make the stimulator remote controlled to give the subject more freedom.

We could keep writing a lot more about this stimulator, but movies might be much more self explaining and fun to watch. Therefore, simply click the following link to see the effects of Vestibular Stimulators:

Movie 1

Movie 2

Marijn

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Posted in Brain-Machine Interfaces, Electronics, General, Neurostimulation and Neuromodulation

The Voices of DAC—A chip in your brain?

Posted on 23/08/2011 by | Leave a comment

Jan Rabaey, UC Berkeley, about brain-machine interfaces. Click here to watch the video.

This talk covers a little bit of transcutaneous signal and energy transfer, recording of brain signals, polymer electrode arrays, brain waves, EEG, ECoG, epilepsy, neurostimulation, DBS, 65nm, microwatt, pulsed waveform, temperature rise, digital amplifier, subthreshold logic, interference, frequency agile radios, security, neural dust…

Wouter

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Posted in Brain-Machine Interfaces, Electronics, General

Timing in the brain not only a matter of time

Posted on 23/08/2011 by | Leave a comment

In the Proceedings of the Royal Society B (Biology) of August 10, 2011, interested readers can read in an article by James Heron that  "duration perception […] may be mediated via a system of duration-selective ‘channels’, which
are differentially activated depending on the match between afferent
duration information and the channels’ ‘preferred’ duration." This is an interesting postulation which may, however, be incorrect, as, to the best of my knowledge (though I am not a physician), there are no particular channel-like structures associated with our sensors (ears and eyes) that can be held responsible for our understanding of how long a particular event lasts. 

From a mathematical and engineering perspective it is also known that there exists a strong relation between time and frequency, taught to us in high school when we learn about the meaning of T = 1/f, T being the period of a (periodical) signal and f its frequency. Some people are known for having an "absolute pitch", sometimes erroneously called "absolute hearing", in the sense that they recognize exactly the pitch of a tone they hear. Most people do not have this remarkable talent, but are nevertheless still pretty good at estimating the approximate pitch of a tone they hear.

Also, it is known that events seem to last longer when they are dull or not exciting and its opposite is probably best illustrated by the expression "time flies when you’re having fun", Also, and this many of us have experienced during the ELCA music festival of last March, sometimes, when excited, a little bit tensed or under pressure, musicians have a tendency to play their songs faster, with more beats per minute, without being aware of it. Apparently, in a more stressful situation, our notion of time becomes related to a faster clock, or a shorter time duration. Finally, it is known that when people are feverish, also their notion of time changes.

The above relation between time and frequency and thus pitch and the experience of time and frequency stretch depending on our excitement, suggest, at least to me, that our notion of time is not so much related to a static entity in the form of a channel, but rather is linked to our internal oscillatory processes, as, e.g., happen in the brain between its various hierarchical layers, or in our lifesupporting master clock, the heart. It would be interesting to see whether the above states of excitement also affect the frequency of our brain waves (alpha, beta and gamma waves). If so, the issue of reliable tinnitus detection (see Senad’s previous post) may become more patient and situation-specific and thus more difficult to implement.

Stay tuned 😉

Wouter

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Posted in General, Understanding the Brain

A first proof-of-principle of a Tinnitus detector circuit

Posted on 27/07/2011 by | 1 comment

Tinnitus is a condition in which a patient perceives an auditory phantom sound that can take the form of ringing, buzzing, roaring or hissing in the absence of an external sound. Approximately a billion of people suffer from tinnitus worldwide, while in 2% – 3% of the population, tinnitus significantly degrades quality of life of the patients and can lead to insomnia, anxiety and depression.

Currently, there are no proven treatments for tinnitus. However, recent research has shown that tinnitus patients can benefit from electrical brain stimulation. In addition, it has been shown that there is a link between tinnitus perception and a change in the energy levels of several electrocortigography (ECoG) / electroencephalography (EEG) frequency bands. For example, the energies of theta (4-8Hz) and low-gamma (30-50Hz) waves increase, while the energy of alpha (8-12Hz) waves decreases during active tinnitus perception. The same studies suggest that the intensity of the tinnitus perception correlates with the amount of the energy increased in the gamma band.

The real-time tinnitus detection method proposed by the BME group detects tinnitus by comparing ECoG/EEG signal energies from different locations in the brain according to a tinnitus "signature". First, the proposed strategy selects appropriate ECoG/EEG bands per channel by means of band-pass filters. Next, their extracted energies are compared to their counterparts from a different (healthy) location. Tinnitus is detected only if higher theta and gamma energies while lower alpha energy is found when compared to the signals from this healthy region. The applicability of the detector is verified by means of circuit simulations with real neural waveforms and is able to successfully detect tinnitus.

Are you interested in any progress related to the tinnitus detector circuit? Stay tuned.

Senad 

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Posted in Education, Electronics, General, Neurostimulation and Neuromodulation, Understanding the Brain

Small chip to overcome inflammation of joints

Posted on 18/07/2011 by | 1 comment

Today, the Telegraaf and Nu.nl report that a team of the Dutch rheumatologist Paul-Peter Tak of the Amsterdam Academic Medical Center will implant a kind of pacemaker, its size in the order of a bout a square centimeter, that will deliver stimuli to the vagus nerve for about one minute a day. By doing so, it is expected that inflammation of the joints of patients that suffer from rheumatoid arthritis can be reduced or even completely stopped.

Of course, what can be deduced from the article is that this pacemaker, electronics-wise, is nothing more than a simple blinking light with a timer, which can be implemented by means of a miniature microcontroller and a battery. However, it is also obvious that electrical stimulation of the vagus nerve, albeit at its infancy, is already very promising and a possible treatment of a wide range of neural disorders and pain is dawning at the horizon.

Wouter

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Posted in Electronics, General, Neurostimulation and Neuromodulation