Cochlear implant development going at a rapid pace (in Dutch)

Posted on 27/03/2015 by | Leave a comment

Uit “De Audiciens”, februari 2015: “CI’s (cochleaire implantaten, Red.) volop in ontwikkeling.

Het is een traditie, de refereeravond van KNO/Centrum voor Audiologie en Hoorimplantaten (CAHIL) in het LUMC op de tweede donderdag van het jaar.

Ook op 8 januari 2015 zit de collegezaal weer vol. Het is dan ook een bijeenkomst waar een aantal disciplines uit de hoorbranche samenkomen. KNO-artsen, audiologen, akoepedisten, audiciens, fabrikanten en anderen luisteren naar voordrachten die inzicht geven in nieuwe ontwikkelingen op audiologisch gebied.

De avond wordt geopend door prof. dr. ir. J.H.M. Frijns, hoofd CAHIL. (…) In het kader van de Medical Delta (een samenwerkingsverband tussen het Erasmus MC in Rotterdam, de TU Delft en het LUMC in Leiden voor de ontwikkeling van medische technologie) is er een presentatie van Johan de Vos die als arts-onderzoeker KNO onderzoek verricht naar nieuwe technologie voor cochleaire implantaten. Onder begeleiding van Wouter Serdijn en Paddy French hebben drie promovendi van de TU een meetversterker (Cees Jeroen Bes), een elektrode ontwerp (Nishant Lawant) en een stimulatorchip (Wannaya Ngamkham) ontwikkeld. Deze technologie wordt onder leiding van Johan Frijns en Jeroen Briaire in het LUMC geimplanteerd en getest door Johan de Vos. Tevens ontwikkelt het LUMC nieuwe meetmethodes voor het terugmeten van de respons van de gehoorzenuw (Dick Biesheuvel).”

Lees meer hier.

Leave a comment

Posted in General

We cured several mice from epilepsy!

Posted on 18/03/2015 by | Leave a comment

The cerebellum might be able to stop epileptic seizures

A single short-lasting (30-300 ms) optogenetic stimulation of the cerebellum (the small brains) abruptly stopped generalized spike-wave discharges (GSWDs) as occur, e.g., in absence epileptic seizures, even when applied unilaterally. Using a closed-loop system absence seizures were detected and stopped within 500 ms.

If you want to read more about the neuroscientific aspects, click here. If you want to read more about the epilepsy detector we developed, click here.

We are now working on our next mission: to reliably detect other forms of epileptic seizures and to study cerebellar nuclei further and their potential therapeutic benefit for controlling other types of generalized epilepsies.

Exciting times ahead, if you ask me, and not only for mice.

Leave a comment

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

Cerebellar output controls generalized spike-and-wave discharge occurrence

Posted on 15/03/2015 by | Leave a comment

Cerebellar output controls generalized spike-and-wave discharge occurrence.

Kros L, Eelkman Rooda OH, Spanke JK, Alva P, van Dongen MN, Karapatis A, Tolner EA, Strydis C, Davey N, Winkelman BH, Negrello M, Serdijn WA, Steuber V, van den Maagdenberg AM, De Zeeuw CI, Hoebeek FE.

Abstract

OBJECTIVE:

Disrupting thalamocortical activity patterns has proven to be a promising approach to stop generalized spike-and-wave discharges (GSWDs) characteristic of absence seizures. Here, we investigated to what extent modulation of neuronal firing in cerebellar nuclei (CN), which are anatomically in an advantageous position to disrupt cortical oscillations through their innervation of a wide variety of thalamic nuclei, is effective in controlling absence seizures.

METHODS:

Two unrelated mouse models of generalized absence seizures were used; the natural mutant tottering, which is characterized by a missense mutation in Cacna1a, and inbred C3H/HeOuJ. While simultaneously recording single CN neuron activity and electrocorticogram (ECoG) in awake animals, we investigated to what extent pharmacologically increased or decreased CN neuron activity could modulate GSWD occurrence and short-lasting on-demand CN stimulation could disrupt epileptic seizures.

RESULTS:

We found that a subset of CN neurons shows phase-locked oscillatory firing during GSWDs and that manipulating this activity modulates GSWD occurrence. Inhibiting CN neuron action potential firing by local application of the GABAA -agonist muscimol increased GSWD occurrence up to 37-fold, whereas increasing the frequency and regularity of CN neuron firing with the use of gabazine decimated its occurrence. A single short-lasting (30-300 ms) optogenetic stimulation of CN neuron activity abruptly stopped GSWDs, even when applied unilaterally. Using a closed-loop system GSWDs were detected and stopped within 500 ms.

INTERPRETATION:

CN neurons are potent modulators of pathological oscillations in thalamocortical network activity during absence seizures and their potential therapeutic benefit for controlling other types of generalized epilepsies should be evaluated.

This article is protected by copyright. All rights reserved.

© 2015 American Neurological Association.

PMID: 25762286
[PubMed – as supplied by publisher]

Leave a comment

Posted in General, Neurostimulation and Neuromodulation, Understanding the Brain

How to optimize the antenna-electronics interface

Posted on 13/03/2015 by | Leave a comment
Autonomous Wireless ECG Sensor Node by Andre Mansano and Yongjia Li

Autonomous Wireless ECG Sensor Node by Andre Mansano and Yongjia Li

During the design process of a wireless system, the antenna and electronic circuit designers sometimes are operating independently from each other and considered to belong to separate disciplines. Both designers agree upon a common characteristic impedance (Z0) of the antenna electronics interface and subsequently optimize their part of the system. The electronic circuit often requires an impedance transformation network while the antenna usually is directly matched to the characteristic impedance of a transmission line to avoid propagation effects in the interface. Traditionally, this characteristic impedance is commonly assumed to be 50 Ω, without any further discussion. Although this standardization may be convenient from a measurement point of view, it is a rather uncomfortable assumption to make as it clearly cannot be the optimum impedance for all design challenges when for example considering noise performance, efficiency or antenna size.

By co-designing the antenna-electronics interface, both disciplines share a common optimization target and can agree on an alternative interface impedance to optimize the overall system performance for a specific application. The choice of interface impedance plays a crucial role in the optimization of antenna systems in the receiving mode, which is the topic addressed in this brief.

Read more in this paper by Mark Stoopman and Yao Liu here.

Leave a comment

Posted in General

Rewiring the brain – creating artificial vision

Posted on 11/03/2015 by | Leave a comment
creating artificial vision

creating artificial vision

For our course “Introduction in Microelectronics” MSc student Lucas van Dijk wrote an inspiring essay about how you can either restore vision for the blind or create enhanced vision for people that see normally.

The essay can be found here.

The abstract reads: “The current state of visual prostheses progresses rapidly. In this essay three approaches to a visual prosthesis are discussed: an epiretinal implant, a visual prosthesis which stimulates the optic nerve, and a visual prosthesis which stimulates the lateral geniculate nucleus. While the epiretinal implants are currently the most advanced visual prostheses available, I think
a visual prosthesis stimulating the lateral geniculate nucleus has the greatest potential, especially when you also keep applications for people with healthy vision.”

Enjoy!

Leave a comment

Posted in General

Building a Bionic Nervous System

Posted on 13/02/2015 by | Leave a comment

Electroceuticals Inside!

“It’s an electrifying time to be in neuroscience. Using implanted devices that send pulses of electricity through the nervous system, physicians are learning how to influence the neural systems that control people’s bodies and minds. These devices give neurologists new ways to treat patients with a wide range of disorders, including epilepsy, chronic pain, depression, and Parkinson’s disease. So far, these stimulators have been oneway devices that deliver a steady sequence of pulses to the nervous system but can’t react to changes in the patient’s body. Now, at last, medical device companies are coming out with dynamic neural stimulators that have a bit of “brain” themselves. These smart systems can detect changes in a physiological signal and then respond by delivering a therapy or adjusting the patient’s treatment in real time.”

Abstract of a paper by Tim Denison, Milton Morris and Felice Sun in IEEE Spectrum, Febr. 2015, DOI: 10.1109/MSPEC.2015.7024509.

Leave a comment

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

A 0.042 mm^2 programmable biphasic stimulator for cochlear implants suitable for a large number of channels

Posted on 03/02/2015 by | Leave a comment

ArXiv-paper on miniature neurostimulator circuit

Today we published the following (scientific) paper online:

A 0.042 mm^2 programmable biphasic stimulator for cochlear implants suitable for a large number of channels
W. Ngamkham; M.N. van Dongen; W.A. Serdijn; C.J. Bes; J.J. Briaire; J.H.M. Frijns; 
ArXiv.org, 
January 29 2015. 

Abstract

This paper presents a compact programmable biphasic stimulator for cochlear implants. By employing double-loop negative feedback, the output impedance of the current generator is increased, while maximizing the voltage compliance of the output transistor. To make the stimulator circuit compact, the stimulation current is set by scaling a reference current using a two stage binary-weighted transistor DAC (comprising a 3 bit high-voltage transistor DAC and a 4 bit low-voltage transistor DAC). With this structure the power consumption and the area of the circuit can be minimized. The proposed circuit has been implemented in AMS 0.18µm high-voltage CMOS IC technology, using an active chip area of about 0.042mm^2. Measurement results show that proper charge balance of the anodic and cathodic stimulation phases is achieved and a dc blocking capacitor can be omitted. The resulting reduction in the required area makes the proposed system suitable for a large number of channels.

Keywords:

current generator, current source, current mirror, output impedance, stimulator
circuit, current stimulator, programmable stimulator, biphasic stimulation, neural stimulation, cochlear implants, electrode-tissue interface, electrode-tissue impedance, switch array, charge error, charge balancing, neurostimulator.

Leave a comment

Posted in Electronics, General, Neurostimulation and Neuromodulation

Aftermovie of The Border Sessions, featuring Wouter Serdijn

Posted on 20/12/2014 by | Leave a comment

Remember the blog about the Border Sessions, held on Nov. 12 and 13 in The Hague and where I gave a talk on Getting Better with Electricity? See a small excerpt in the aftermovie made by Daniel.

[youtube]http://www.youtube.com/watch?v=epfjh4mjubM[/youtube]

Leave a comment

Posted in General

Laagfrequente tinnitus

Posted on 05/11/2014 by | Leave a comment
Foto en artwork: Marleen Serdijn

Foto en artwork: Marleen Serdijn http://instagram.com/marleen.serdijn/

Vandaag ontving ik een email van een lezer van de Bioelectronics weblog, met daarin de vraag of neuromodulatie ook zin heeft in de behandeling van laagfrequente tinnitus, d.w.z., tinnitus die zich manifesteert als een gebrom of gezoem in plaats van een hoge (fluit-) toon.

Hieronder een deel van mijn reactie aan deze lezer, in de hoop dat het ook nuttig kan zijn voor andere mensen die lijden onder tinnitus.

Beste [afzender van de email],

(…)

Voor zover ik heb begrepen is tinnitus potentieel goed te behandelen indien het zijn oorsprong vindt in de gehoorschors en zich nog niet erg lang manifesteert (minder dan een paar jaren). [Prof.] Dirk de Ridder [verbonden aan het St. Augustinus Ziekenhuis in Antwerpen] en zijn team onderzoeken hoe ze de structurele verandering van de gehoorschors, bijv. ontstaan als gevolg van een gehoortrauma (bijvoorbeeld luid geluid), ongedaan kunnen maken door neuromodulatie, al of niet vergezeld van andere vormen van stimulatie. Of de tinnitus hoog- of laag-frequent is maakt volgens mij niet fundamenteel uit. Het kan wel betekenen dat de tinnitus een andere oorzaak heeft en dus anders “in de hersenen geprogrammeerd” en daarmee minder goed te behandelen is. Er is bijvoorbeeld een vaak voorkomende relatie tussen gehoorverlies en het optreden van tinnitus.

Als technisch wetenschapper probeer ik verbeterde technologie te ontwikkelen die de neurowetenschappers en neurochirurgen in staat stelt betere behandelingen te ontwikkelen, die minder invasief is en zich automatisch aanpast aan de therapeutische behoeften patient.

Ik hoop dat u iets aan het bovenstaande heeft.

Met vriendelijke groet,

Wouter Serdijn

—

Wouter A. Serdijn, PhD, F-IEEE, DL-IEEE Head Section Bioelectronics

Delft University of Technology Faculty of Electrical Engineering, M&CS Mekelweg 4, 2628 CD Delft The Netherlands Phone/Fax: +31-15-278-1715/5922 Email: w.a.serdijn@tudelft.nl serdijn@ieee.org http://elca.et.tudelft.nl/~wout http://bioelectronics.tudelft.nl

Leave a comment

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

Wouter Serdijn at Crossing Borders Festival in The Hague, Nov. 12, 13:00 hrs

Posted on 23/10/2014 by | Leave a comment

The 21st century will be the century in which we will unravel the intricacies of the brain and in which we will use electricity to interact with our electro-chemical mainframe better. At Border Sessions

Example of an electroceutical: a cochlear implant. Today, more than 250,000 people have cochlear implants worldwide.

Wouter Serdijn will explain how electroceuticals, the electronic counterparts of pharmaceuticals, can help to successfully treat neurological disorders. Further, he will sketch a technological avenue of their future development by making electroceuticals smaller, more energy efficient and more intelligent. Examples will be given for fully-implantable bionic ears and neurostimulators for the treatment of tinnitus, Tourette’s syndrome and epilepsy.

Leave a comment

Posted in General