Showing papers on "Electrode array published in 2006"

Low voltage flexible organic/transparent transistor for selective gas sensing, photodetecting and CMOS device applications

Abstract: A thin film transistor (TFT) includes a source electrode, a drain electrode, and a gate electrode. A gate insulator is coupled to the source electrode, drain electrode, and gate electrode. The gate insulator includes room temperature deposited high-K materials so as to allow said thin film transistor to operate at low operating voltage.

A Low-Power Integrated Circuit for a Wireless 100-Electrode Neural Recording System

Abstract: Recent work in field of neuroprosthetics has demonstrated that by observing the simultaneous activity of many neurons in specific regions of the brain, it is possible to produce control signals that allow animals or humans to drive cursors or prosthetic limbs directly through thoughts. As neuroprosthetic devices transition from experimental to clinical use, there is a need for fully-implantable amplification and telemetry electronics in close proximity to the recording sites. To address these needs, we developed a prototype integrated circuit for wireless neural recording from a 100-channel microelectrode array. The design of both the system-level architecture and the individual circuits were driven by severe power constraints for small implantable devices; chronically heating tissue by only a few degrees Celsius leads to cell death. Due to the high data rate produced by 100 neural signals, the system must perform data reduction as well. We use a combination of a low-power ADC and an array of "spike detectors" to reduce the transmitted data rate while preserving critical information. The complete system receives power and commands (at 6.5 kb/s) wirelessly over a 2.64-MHz inductive link and transmits neural data back at a data rate of 330 kb/s using a fully-integrated 433-MHz FSK transmitter. The 4.7times5.9 mm2 chip was fabricated in a 0.5-mum 3M2P CMOS process and consumes 13.5 mW of power. While cross-chip interference limits performance in single-chip operation, a two-chip system was used to record neural signals from a Utah Electrode Array in cat cortex and transmit the digitized signals wirelessly to a receiver

Stimulator system with electrode array and the method of making the same

Abstract: An implantable microstimulator can include a housing with a surface containing a metal region. The housing defines an exterior and an interior. At least one conductive electrode is disposed on the exterior of the housing over the metal region of the housing. Adhesive is disposed between the metal region of the housing and the conductive electrodes. An electronic subassembly is disposed in the interior of the housing and coupled to the conductive electrodes through the housing.

Piezoelectric composite device, method of manufacturing same, method of controlling same, input-output device, and electronic device

Abstract: A piezoelectric composite device including: a feeding electrode; a common electrode; a signal detecting electrode; a first piezoelectric element joined between the feeding electrode and the common electrode; and a second piezoelectric element joined between the common electrode and the signal detecting electrode; a predetermined voltage being supplied between the feeding electrode and the common electrode; and a force detection signal based on an external force being extracted from the detecting electrode.

Flexible Circuit Electrode Array

Abstract: Polymer materials are useful as electrode array bodies for neural stimulation They are particularly useful for retinal stimulation to create artificial vision, cochlear stimulation to create artificial hearing, or cortical stimulation many purposes The pressure applied against the retina, or other neural tissue, by an electrode array is critical Too little pressure causes increased electrical resistance, along with electric field dispersion Too much pressure may block blood flow Common flexible circuit fabrication techniques generally require that a flexible circuit electrode array be made flat Since neural tissue is almost never flat, a flat array will necessarily apply uneven pressure Further, the edges of a flexible circuit polymer array may be sharp and cut the delicate neural tissue By applying the right amount of heat to a completed array, a curve can be induced With a thermoplastic polymer it may be further advantageous to repeatedly heat the flexible circuit in multiple molds, each with a decreasing radius Further, it is advantageous to add material along the edges It is further advantageous to provide a fold or twist in the flexible circuit array Additional material may be added inside and outside the fold to promote a good seal with tissue

Temporal Bone Results and Hearing Preservation with a New Straight Electrode

Abstract: Due to improved technology, cochlear implant (CI) candidacy has been widened towards patients with usable residual hearing in the low frequency range. These patients might benefit from additional acoustic amplification provided that residual hearing can be preserved with cochlear implantation. To provide a high probability of hearing preservation, a new electrode array was designed and developed at the Medizinische Hochschule Hannover. This 'Hybrid-L' electrode array has 22 electrodes spread over 15 mm with an overall insertion depth of 16 mm. The straight electrode with modiolus facing contacts is designed for a round window insertion. It shall provide the full range of the currently most advanced Nucleus CI system. A temporal bone study demonstrated the favorable insertion characteristics and minimized trauma to intracochlear structures. Compared to standard CI electrodes especially no basilar membrane perforation could be found. So far, 4 patients have been implanted and residual hearing could be preserved. One patient was fitted and showed a marked additional benefit from the electroacoustic stimulation compared to either acoustic or electrical stimulation alone. These results are very encouraging towards a concept of reliable hearing preservation with cochlear implantation.

Hermetically sealed three-dimensional electrode array

Abstract: The electrode array is a device for making electrical contacts with cellular tissue or organs. The electrode array includes an assembly of electrically conductive electrodes arising from a substrate where the electrodes are hermetically bonded to the substrate. The electrodes also include an insulating layer which leaves at least one zone or at least one hole exposed for making focused electrical contact with the tissue. A hole passing completely or partially through the electrode may further provide an anchor to the living tissue, thereby stabilizing the array with respect to the tissue being examined. Also, a method of manufacture of an electrode array and associated circuitry is disclosed.

Devices and Methods for Thermal Ablation of Biological Tissue Using Geometric Ablation Patterns

Abstract: A tissue ablation system including numerous components and methods is described herein for encircling target tissue and generating tissue ablation volumes in various biological tissues. The biological tissue includes tissue of a variety of organs of the human body including the liver, spleen, kidney, lung, breast and other organs, but is not so limited. The tissue ablation device comprises an energy source and at least one trocar coupled to the energy source, the trocar having a body, a proximal end, and a distal end. The trocar carries an electrode array that comprises a plurality of electrodes, each electrode of the plurality of electrodes is configured to extend from the trocar when moved from a retracted state to a deployed state, and to have at least one radius of curvature in the deployed state so that the electrode array forms a series of shaped electrodes in the deployed state.

A 32-Site 4-Channel High-Density Electrode Array for a Cochlear Prosthesis

Abstract: This paper describes a 32-site 4-channel high-density intracochlear electrode array. Combining MEMS-based processing technology with active circuitry, the thin-film device realizes a stimulating site density three times that of commercial systems, delivering 500 muA biphasic current levels with 8-bit resolution and less than 1% charge mismatch. The minimum pulsewidth is 4 mus, and the per-channel power dissipation is 2.5 mW from plusmn2.5 V. The active circuit chip has a footprint of 2.4mmtimes2.9 mm. Serving as the end-effector of a cochlear prosthesis, the active array also provides site-impedance measurement and position-sensing functions

Modular multichannel microelectrode array and methods of making same

Abstract: Some embodiments of the invention comprise a customizable multichannel microelectrode array with a modular planar microfabricated electrode array attached to a carrier and a high density of recording and/or stimulation electrode sites disposed thereon. Novel methods of making and using same are also disclosed.

16-Channel Integrated Potentiostat for Distributed Neurochemical Sensing

Abstract: We present the architecture and VLSI circuit implementation of a BiCMOS potentiostat bank for monitoring neurotransmitter concentration on a screen-printed carbon electrode array. The potentiostat performs simultaneous acquisition of bidirectional reduction-oxidation currents proportional to neurotransmitter concentration on 16 independent channels at controlled redox potentials. Programmable current gain control yields over 100-dB cross-scale dynamic range with 46-pA input-referred rms noise over 12-kHz bandwidth. The cutoff frequency of a second-order log-domain anti-aliasing filter ranges from 50 Hz to 400 kHz. Track-and-hold current integration is triggered at the sampling rate between dc and 200 kHz. A 2.25-mmtimes2.25-mm prototype was fabricated in a 1.2-mum VLSI technology and dissipates 12.5 mW. Chronoamperometry dopamine concentration measurements results are given. Other types of neurotransmitters can be selected by adjusting the redox potential on the electrodes and the surface properties of the sensor coating

Electrode array for neural stimulation

Abstract: An electrode array for neural stimulation is disclosed which has particular applications for use in a retinal prosthesis. The electrode array can be formed as a hermetically-sealed two-part ceramic package which includes an electronic circuit such as a demultiplexer circuit encapsulated therein. A relatively large number (up to 1000 or more) of individually-addressable electrodes are provided on a curved surface of a ceramic base portion the electrode array, while a much smaller number of electrical connections are provided on a ceramic lid of the electrode array. The base and lid can be attached using a metal-to-metal seal formed by laser brazing. Electrical connections to the electrode array can be provided by a flexible ribbon cable which can also be used to secure the electrode array in place.

Neural stimulation lead fixation

Abstract: An implantable lead having at least one electrode contact at or near its distal end prevents undesirable movement of the electrode contact from its initial implant location. One embodiment relates to a spinal cord stimulation (SCS) lead. A first injectable material is injected into the dura space to mechanically position the electrode array with respect to the spinal cord. Conjunctively for use with adhesives, or alternatively for use instead of the adhesives, a balloon may be positioned on the electrode lead array. The balloon is filled with air, liquid or a compliant material. When inflated, the balloon stabilizes the lead with respect to the spinal cord and holds the lead in place. An elastic aspect of the balloon serves as an internal contained relief valve to limit the pressure the balloon may place on the surrounding tissues when the epidural space is constrained.

Thermal hemostasis and/or coagulation of tissue

Abstract: Energy delivery systems and methods are provided for use in biological tissue. The energy delivery system includes an energy source and an electrode array. The electrode array includes bipolar electrodes positioned so a first spacing between a pair of adjacent electrodes is different relative to a second spacing between at least one other pair of adjacent electrodes. The electrode array and the energy source are coupled and configured to generate uniform energy density in target tissue according to impedance of the target tissue.

Transverse tripole neurostimulation lead, system and method

Abstract: An implantable neurostimulation lead, method and system adapted for tripolar electric simulation and/or field steering. The neurostimulation lead is are adapted to provide an electrode array defining, for example, a plurality of electrode sets that may be used to provide tripolar stimulation and/or electric field steering.

Focused stimulation in a medical stimulation device

Abstract: A medical stimulation device such as a cochlear implant configured to provide stimulation of one or more spatially-restricted contiguous portion(s) of the spiral array of auditory nerve fibers in the cochlear ('discrete stimulation regions'). Each discrete stimulation region is defined by the constructive and/or destructive interference of stimulating and limiting signals simultaneously applied to electrode channels of an implanted electrode array, the stimulating and limiting signals being determined based upon transimpedaπce measurements of intracochlear electrode channels of the implanted electrode array representing specific spread functions of an individual recipient. The stimulating signal is preferably applied through a targeted electrode channel; that is, one or more successive electrodes which is/are adjacent to the discrete stimulation region. The targeted electrode channel is selected to represent sound based on the outputs of a sound processor to stimulate neural activity in the discrete stimulation region to thereby cause a percept of the represented sound.

Effect of deep insertion of the cochlear implant electrode array on pitch estimation and speech perception.

Abstract: Conclusion. Deeply inserted electrodes offer the possibility that apical stimulation may improve speech performances. Therefore, deep insertion is reasonable and should be performed in patients with profound or total hearing loss. Objectives. To evaluate the importance of insertion depth beyond 25 mm in a group of cochlear implant patients with deeply inserted electrodes up to 32 mm. Patients and methods. In the first part of the study patients were asked to perform a pitch estimation for channels across the whole length of the electrode array. We evaluated whether pitch discrimination was possible along the whole cochlea and especially in its apical part. Then, the audiological performances of 10 patients were tested in 5 conditions, in which we artificially varied the insertion depth in each patient by activating and deactivating channels. The patients were tested immediately in the new condition to avoid adaptation. Results. The results showed that activating the electrodes in the uppermost region of t...

A 3D paired microelectrode array for accumulation and separation of microparticles

Abstract: This paper presents a microfluidic system comprising a three-dimensional microelectrode structure for accumulation and separation of micro-sized particles based on the combination of negative dielectrophoresis (DEP) and hydrodynamic force. The paired electrode array is constructed by aligning two layers of microelectrode structure face to face on the top and bottom sides of the microchannel. Dielectrophoretic gates are generated between the top and bottom electrodes with high-frequency ac voltage. These gates are designed to study the behavior of microparticles such as polystyrene beads or cells carried by a laminar flow past the electrodes. Depending on the relative strength of the DEP force and hydrodynamic force acting on the particles, the particles can either penetrate the gates or settle by the gates. The threshold velocity at which the particles begin to penetrate the gates depends on a number of parameters such as channel height, particle size, dielectric properties, electrode width and local heating, etc. A wide range of these parameters give rise to approaches of accumulating and separating microparticles. For this purpose, a microfluidic device with the paired microelectrode array sitting on the channel has been designed and fabricated using microfabrication techniques. Polystyrene beads were used to study the performance of the device and particle behavior. Using a proper range of flow rates, particle accumulation and separation are successfully achieved with the microsystem.

Retinal prosthesis with a new configuration

Abstract: Polymer materials are useful as electrode array bodies for neural stimulation. They are particularly useful for retinal stimulation to create artificial vision, cochlear stimulation to create artificial hearing, and cortical stimulation, and many related purposes. The pressure applied against the retina, or other neural tissue, by an electrode array is critical. Too little pressure causes increased electrical resistance, along with electric field dispersion. Too much pressure may block blood flow. Common flexible circuit fabrication techniques generally require that a flexible circuit electrode array be made flat. Since neural tissue is almost never flat, a flat array will necessarily apply uneven pressure. Further, the edges of a flexible circuit polymer array may be sharp and cut the delicate neural tissue. By applying the right amount of heat to a completed array, a curve can be induced. With a thermoplastic polymer it may be further advantageous to repeatedly heat the flexible circuit in multiple molds, each with a decreasing radius. Further, it is advantageous to add material along the edges. It is further advantageous to provide a fold or twist in the flexible circuit array. Additional material may be added inside and outside the fold to promote a good seal with tissue.

Continuous flow microfluidic demixing of electrolytes by induced charge electrokinetics in structured electrode arrays.

Abstract: A continuous flow microfluidic demixing process is realized. It utilizes high external electrical fields that are applied over electrically floating noble metal electrodes in an otherwise straight microchannel. The process converts axial electrical potential gradients into lateral molecular selective transport via a structure oriented ensemble of numerous electrodes. While the individual electrodes locally modify the electrolyte distribution by nonlinear electrokinetic effects and concentration polarization, the directed orientation of the electrode array combines the individual polarization zones to a dedicated molecular enrichment against the generated concentration gradient. A homogeneously concentrated electrolyte can be separated into arbitrarily shaped laminae of increased and depleted concentration by the presented microfluidic demixer.

Hemostasis and/or coagulation of tissue

Abstract: A tissue treatment apparatus is described that includes a housing having a proximal end and a distal end including a tissue contacting surface having a plurality of apertures. The housing defines an interior. An electrode array is positionable in the housing interior. The electrode array includes a plurality of bipolar electrodes. The electrode array is configured to be advanced from the housing interior so a first spacing between a deployed pair of electrodes of the plurality of electrodes is different relative to a second spacing between at least one other deployed pair of electrodes. An advancement device is configured to selectively advance the plurality of electrodes from the housing interior into a target tissue site and withdraw advanced electrodes into the housing interior.

Electro-optical arrangement

Abstract: An electro-optical arrangement includes an electro-optical device, which can take either a first display state or a second display state, and a driving stage which provides first and second electrode-drive signals to drive the first and second electrodes of the device. The driving stage in an initial clearing operation outputs a voltage across the electrodes, which places the device into its second display state corresponding to a second coloration of the device. Subsequently the driver stage applies voltages to the electrodes, such that the device assumes either the first display state (a first coloration) or the second display state (maintained second coloration). This is a writing phase of the device. In either state it is arranged for the device not to be subjected to more than a safe operating voltage across its electrodes. Preferably the device is an electrophoretic device and, in one of its two display states, one of its electrodes is supplied with a voltage which is higher than the voltage (Vcom) on the other electrode, while in the other of its two display states the one electrode is supplied with a voltage which is lower than the voltage (Vcom) on the other electrode, the voltage (Vcom) on the other electrode in one embodiment being approximately midway between the two voltages on the one electrode and the two voltage differences each being less than the safe operating voltage. A greyscale driving scheme is also envisaged.

Elimination of facial nerve stimulation by reimplantation in cochlear implant subjects

Abstract: Hypothesis Perimodiolar intracochlear electrodes with contacts facing towards the modiolus have limited current flow towards the outer wall of the cochlea and therefore, may reduce the occurrence of facial nerve stimulation (FN) in cochlear implant subjects. Background Facial nerve stimulation is a well-known complication in cochlear implant treatment especially in the group of subjects with otosclerosis. The possible explanation of this side effect is a change of the electrical properties of the otosclerotic bone leading to leakage current and resulting in facial nerve stimulation. Methods Four CI subjects who had been implanted with a Nucleus Mini22 device with a Nucleus Straight electrode between 9 to 12 years ago suffered from severe FN stimulation. Electrode contacts had to be switched off so that they could only use 4, 11, 13, and 15 electrodes of their usual set of 22. The switch off resulted in deteriorating speech understanding over time. Therefore, all subjects were reimplanted with a Nucleus 24R device with a Contour electrode. Preoperatively, the threshold of FN stimulation was obtained on all electrodes subjectively. Intraoperatively, FN stimulation thresholds were measured objectively with both, the old and the new device and were compared. NRT and SRT thresholds were also obtained with the reimplanted device to assure effective electrical stimulation of the auditory nerve. Results In all four cases the postoperative fitting demonstrated no FN stimulation on all electrodes up to maximum comfortable level. The insertion of the Contour electrode array was complete in three cases, in one case the array could only be inserted partially similarly to the situation before the reimplantation. Speech perception tests showed a significant improvement in all subjects with the new device. Conclusion Electrodes with modiolar facing contacts and perimodiolar position like the Nucleus Contour electrode reduce the possibility of facial nerve stimulation significantly due to more focused electrical stimulation.

Method of and system for stabilization of sensors

Abstract: A blood glucose sensing system includes a sensor and a sensor electronics device. The sensor includes a plurality of electrodes. The sensor electronics device includes stabilization circuitry. The stabilization circuitry causes a first voltage to be applied to one of the electrodes for a first timeframe and causes a second voltage to be applied to one of the electrodes for a second timeframe. The stabilization circuitry repeats the application of the first voltage and the second voltage to continue the anodic-cathodic cycle. The sensor electronics device may include a power supply, a regulator, and a voltage application device, where the voltage application device receives a regulated voltage from the regulator, applies a first voltage to an electrode for the first timeframe, and applies a second voltage to an electrode for the second timeframe.

Electrode system with shunt electrode

Abstract: The invention is directed to electrode systems that may be used with implantable medical devices such as a pacemaker. The electrode systems, in addition to one or more conventional electrodes, include a shunt electrode. Under ordinary conditions, the shunt electrode has very little effect upon the operation of the electrode system. When high frequency current is delivered to the electrode system, however, the electrode system shunts a large share of the high frequency current to the shunt electrode. The shunt electrode, which includes a conducting material surrounded by an insulating layer, dissipates heat that may be caused by the high frequency current.