Showing papers on "Electrode array published in 1999"

Method and apparatus for integrating manual input

Abstract: Apparatus and methods are disclosed for simultaneously tracking multiple finger (202-204) and palm (206, 207) contacts as hands approach, touch, and slide across a proximity-sensing, compliant, and flexible multi-touch surface (2). The surface consists of compressible cushion (32), dielectric electrode (33), and circuitry layers. A simple proximity transduction circuit is placed under each electrode to maximize the signal-to-noise ratio and to reduce wiring complexity. Scanning and signal offset removal on electrode array produces low-noise proximity images. Segmentation processing of each proximity image constructs a group of electrodes corresponding to each distinguishable contacts and extracts shape, position and surface proximity features for each group. Groups in successive images which correspond to the same hand contact are linked by a persistent path tracker (245) which also detects individual contact touchdown and liftoff. Classification of intuitive hand configurations and motions enables unprecedented integration of typing, resting, pointing, scrolling, 3D manipulation, and handwriting into a versatile, ergonomic computer input device.

Liquid crystal display having stripe-shaped common electrodes formed above plate-shaped pixel electrodes

Abstract: An electrode structure has independent pixel electrodes and connected common electrodes for a wide viewing angle liquid crystal display. The pixel electrode being a plate-shaped structure is fabricated on a lower layer above a substrate. The common electrode being a striped-shape structure is formed in an upper layer above the substrate. The common electrode may be a herringbone-shaped structure. The pixel electrodes and the common electrodes may overlay the data signal lines of the liquid crystal display. The arrangement of the electrode structure increases the effective light transmission. The electrode structure has the advantages that the tolerance for an electrostatic breakdown or residual electric charges is increased, and reproduction process is simplified.

Directional programming for implantable electrode arrays

Abstract: A programming system and method for use with an implantable tissue stimulator allows a clinician or patient to quickly determine a desired electrode stimulation pattern, including which electrodes of a multiplicity of electrodes in an electrode array should receive a stimulation current, including the amplitude, width and pulse repetition rate of such current. Such system and method allows the clinician or user to readily select and visualize a particular group of electrodes of the electrode array by displaying a visual image of the array, and then allows selection of a group of electrodes in the array, as well as the ability to move the selected group or change the size of the selected group, while applying a stimulation pulse current having a selected amplitude, width and pulse repetition rate, to the group of electrodes. Movement of the selected group of electrodes is facilitated through the use of a directional pointing device, such as a joystick. Through use of the programming system, the clinician or patient is able to select for stimulation only those electrodes which prove most effective for a desired purpose, e.g., pain relief, to best meet the needs of a particular patient.

Programmable current output stimulus stage for implantable device

Abstract: A programmable output current stage (200) for use within an implantable tissue or nerve stimulator, e.g., an implantable cochlear stimulator or spinal cord stimulator, includes parallel-connected P-FET current source sets (210) connected between a positive voltage rail (+V) and an electrode node (204), and parallel-connected N-FET current source sets (220) connected between the electrode node (204) and a negative voltage rail (-V). The N-FET current source sets (220) include n N-FET current sources (220a, 220b, 220c, 220d, ..., 220n), where n is an integer, and wherein each N-FET current source, when enabled, respectively sinks a current 2nI from the electrode node (204) to the negative rail (-V), where I is a selectable fixed current. Similarly, the P-FET current source sets (210) include n P-FET current sources (210a, 210b, 210c, 210d,..., 210n), and wherein each P-FET current source, when enabled, respectively sources a current 2nI from the positive voltage rail (+V) to the electrode node (204). An individual current pulse is formed by selecting an electrode pair, and enabling a desired combination of P-FET current sources so that a desired total current is sourced to one of the electrodes of the selected electrode pair, and at the same time enabling a corresponding combination of N-FET current sources so that the same total current is sunk from the other electrode of the selected electrode pair. Sequences of current pulses, e.g., biphasic or multiphasic stimulation pulse pairs, are formed by combining individual current pulses having the desired polarity and timing relationship. In one embodiment, the programmable amplitude of the current pulse is further enhanced through the addition of m P-FET and m N-FET current sources (212, 222) as part of the P-FET and N-FET current source sets, respectively, that source or sink a current I/2m, when enabled, where m = 1, 2, 3, ..., m.

A componential analysis of the ERP elicited by novel events using a dense electrode array

Abstract: In this study, we examined the relationship between the novelty P3 and the P300 components of the brain event-related potential (ERP). Fifteen subjects responded manually to the rare stimuli embedded either in a classical auditory oddball series or in a series in which "novel" stimuli were inserted. The electroencephalogram (EEG) was recorded with a dense array of 129 electrodes. The data were analyzed by using spatial Principal Components Analysis (PCA) to identify a set of orthogonal scalp distributions, "virtual electrodes" that account for the spatial variance. The data were then expressed as ERPs measured at each of the virtual electrodes. These ERPs were analyzed using temporal PCA, yielding a set of "virtual epochs." Most of the temporal variance of the rare events was associated with a virtual electrode with a posterior topography, that is, with a classical P300, which was active during the virtual epoch associated with the P300. The novel stimuli were found to elicit both a classical P300 and a component focused on a virtual electrode with a frontal topography. We propose that the term Novelty P3 should be restricted to this frontal component.

Apparatus and method for treating tumors near the surface of an organ

Abstract: A system for treating a target region in tissue beneath a tissue surface comprises a probe for deploying an electrode array within the tissue and a surface electrode for engaging the tissue surface above the treatment site. Preferably, surface electrode includes a plurality of tissue-penetrating elements which advance into the tissue, and the surface electrode is removably attachable to the probe. The tissue may be treated in a monopolar fashion where the electrode array and surface electrode are attached to a common pole on an electrode surgical power supply and powered simultaneously or successively, or in a bipolar fashion where the electrode array and surface electrode are attached to opposite poles of the power supply. The systems are particularly useful for treating tumors and other tissue treatment regions which lie near the surface.

Implantable expandable multicontact electrodes

Abstract: A paddle-type electrode or electrode array is implantable like a percutaneously inserted lead, i.e., without requiring major surgery, but once inserted, expands to provide a platform for many electrode configurations. The electrode array is provided on a flexible, foldable, subcarrier or substrate. Such subcarrier or substrate is folded, or compressed. during implantation, thereby facilitating its insertion using simple, well-known percutaneous implantation techniques. Once implanted, such subcarrier or substrate expands, thereby placing the electrodes in a desired spaced-apart positional relationship, and thus achieving a desired electrode array configuration. A memory element is used within the subcarrier or substrate which causes the electrode array to expand or unfold to a desired unfolded or expanded state after it has been implanted while in a folded up or compressed state. Further, the electrode array includes a membrane as an integral part thereof that prevents ingrowth of tissue inside the electrode array, thereby facilitating repositioning, removal, and/or reinsertion of the electrode array, as required.

Image display device with element driving device for matrix drive of multiple active elements

Abstract: An image display device has multiple active elements arranged therein, such as an organic EL (Electro-Luminescence) element to matrix-drives these active elements. In the image display device, when a switching element is turned on with a control signal applied to a control electrode, a control current on a signal electrode is converted to a control voltage by a second transistor, held in a holding capacitor, and applied to a gate electrode of a first transistor. Thus, the signal electrode is applied with the control current, not with a control voltage, for controlling the operation of the active element. A drive voltage to be applied to a power supply electrode is converted to a drive current and supplied to the active element.

Cochlear implant electrode array

Abstract: An electrode array (10) for a cochlear implant is formed with a carrier made, for example from silicone, is preshaped and is formed with a lumen. The array (10) is shaped to assume a first configuration. The array (10) can be straightened, and held in a straight configuration by inserting a stylet (44) into the lumen. The array (10) relaxes to a shape matching the curvature of the cochlea (48) when the stylet (44) is removed. The electrodes of the array (10) are disposed on one side of the array (10) to face the modiolus when that array (10) is inserted into the cochlea (48).

Chronic intracortical microstimulation (ICMS) of cat sensory cortex using the Utah intracortical electrode array

Abstract: In an effort to assess the safety and efficacy of focal intracortical microstimulation (ICMS) of cerebral cortex with an array of penetrating electrodes as might be applied to a neuroprosthetic device to aid the deaf or blind, the authors have chronically implanted 3 trained cats in primary auditory cortex with the 100-electrode Utah Intracortical Electrode Array (UIEA). Eleven of the 100 electrodes were hard-wired to a percutaneous connector for chronic access. Prior to implant, cats were trained to "lever-press" in response to pure tone auditory stimulation. After implant, this behavior was transferred to "lever-presses" in response to current injections via single electrodes of the implanted arrays. Psychometric function curves relating injected charge level to the probability of response were obtained for stimulation of 22 separate electrodes in the 3 implanted cats. The average threshold charge/phase required for electrical stimulus detection in each cat was, 8.5, 8.6, and 11.6 nC/phase respectively, with a maximum charge/phase of 26 nC/phase and a minimum of 1.5 nC/phase thresholds were tracked for varying time intervals, and 7 electrodes from 2 cats were tracked for up to 100 days. Electrodes were stimulated for no more than a few minutes each day. Neural recordings taken from the same electrodes before and after multiple electrical stimulation sessions were very similar in signal/noise ratio and in the number of recordable units, suggesting that the range of electrical stimulation levels used did not damage neurons in the vicinity of the electrodes. Although a few early implants failed, the authors conclude that ICMS of cerebral cortex to evoke a behavioral response can be achieved with the penetrating UIEA. Further experiments in support of a sensory cortical prosthesis based on ICMS are warranted.

Cochlear electrode array having current-focusing and tissue-treating features

Abstract: An implantable electrode array, adapted for insertion into a cochlea, provides a multiplicity of exposed electrode contacts, each having a shape, geometry, or makeup that aids in controlling the current flow and current density associated with the electrode contact as a function of position on the electrode contact. In one embodiment, the shape or geometry of the exposed electrode contact controls the contact surface of the electrode contact in a way that varies the current flow and current density as a function of surface area position on the electrode, thereby focusing most of the current to flow through the center of the electrode contact. In another embodiment, the electrode contact is coated with a dielectric or other material that controls the surface contact impedance as a function of distance from the center of the electrode, again focusing most of the current flow through the center of the electrode contact. In yet a further embodiment, the exposed electrode contact surface area is masked with an insulator to prevent conduction of current at various locations on the surface of the electrode contact. Separately, or in combination with any of the above embodiments, the exposed electrode contact surface and/or the entire electrode array may be coated with a selected substance or drug compound that diffuses into the tissue and liquids surrounding the electrode. Such substance or drug compound is selected to elicit a desired result, e.g., to inhibit fibrous tissue or bone growth in the vicinity of the electrode contacts; to promote healing of damaged tissue in the region of the electrode contacts, to prevent neural degeneration, or to promote neural regeneration.

Method and apparatus for treating oropharyngeal respiratory and oral motor neuromuscular disorders with electrical stimulation

Abstract: A simple, non-invasive device and method for treating oropharyngeal, respiratory, and oral motor neuromuscular disorders provides electrical stimulation to various regions of a patient. The method and device offer an effective and non-invasive treatment for these disorders. The device is an electrical neuromuscular stimulator that includes a pulse generator for generating a series of electrical pulses and a processor coupled to the pulse generator for controlling its operation. An electrode array of uni-directional or bi-directional electrodes is coupled to the pulse generator and provides electrical stimulation to the appropriate neck, chest, or facial region of the patient. Using bi-directional snap electrodes, for example, the electrode array may also generate electrical feedback signals in response to the neuromuscular stimulation of the patient. The electrical feedback signals are provided to the processor, which generates and stores test data and may modify the operation of the device in response to the electrical feedback signals.

Electro-kinetic air transporter-conditioner

Abstract: An electro-kinetic electro-static air conditioner includes a self-contained ion generator that provides electro-kinetically moved air with ions and safe amounts of ozone. The ion generator includes a high voltage pulse generator whose output pulses are coupled between first and second electrode arrays. Preferably the first array comprises one or more wire electrodes spaced staggeringly apart from a second array comprising hollow “U”-shaped electrodes. Preferably a ratio between effective area of an electrode in the second array compared to effective area of an electrode in the first array exceeds about 15:1 and preferably is about 20:1. An electric field produced by the high voltage pulses between the arrays produces an electrostatic flow of ionized air containing safe amounts of ozone. A bias electrode, electrically coupled to the second array electrodes, affects net polarity of ions generated. The outflow of ionized air and ozone is thus conditioned.

Modeling of surface myoelectric signals. II. Model-based signal interpretation

Abstract: For pt. I see ibid., vol. 46, no. 7, p. 810-20 (1999). Experimental electromyogram (EMG) data from the human biceps brachii were simulated using the model described in pt. I of this work. A multichannel linear electrode array, spanning the length of the biceps, was used to detect monopolar and bipolar signals, from which double differential signals were computed, during either voluntary or electrically elicited isometric contractions. For relatively low-level voluntary contractions (10%-30% of maximum force) individual firings of three to four-different motor units were identified and their waveforms were closely approximated by the model. Motor unit parameters such as depth, size, fiber orientation and length, location of innervation and tendonous zones, propagation velocity, and source width were estimated using the model. Two applications of the model are described. The first analyzes the effects of electrode rotation with respect to the muscle fiber direction and shows the possibility of conduction velocity (CV) over- and under-estimation. The second focuses on the myoelectric manifestations of fatigue during a sustained electrically elicited contraction and the interrelationship between muscle fiber CV, spectral and amplitude variables, and the length of the depolarization zone. It is concluded that a) surface EMG detection using an electrode array, when combined with a model of signal propagation, provides a useful method for understanding the physiological and anatomical determinants of EMG waveform characteristics and b) the model provides a way for the interpretation of fatigue plots.

Multichannel implantable cochlear stimulator

Abstract: An implantable cochlear stimulator (ICS) has eight output stages (212), each having a current source (212B) connected to a pair of electrodes, designated 'A' and 'B', through respective output coupling capacitors and an electrode switching matrix (212C). An indifferent electrode is connected to each output stage by way of an indifferent electrode switch (212D). The current source generates a precise stimulation current as a function of an analog control voltage. The analog control voltage, in turn, is generated by a logarithmic D/A converter. The D/A converter serially converts data words, received in a data frame from an external source, to respective analog control voltages that are applied sequentially to the current sources of each output stage. An output mode register (208) controls the switching matrix of each stage, as well as the indifferent electrode switch, to configure the electrodes for a desired stimulation configuration, e.g., bipolar stimulation (current flow between the pair of electrodes of the output stage), or monopolar stimulation (current flow between one of the electrodes of the output stage and the indifferent electrode). The voltage at the 'A' and 'B' electrode of each output stage may be selectively telemetered to the wearable system, as may the current flow through the indifferent electrode, thereby facilitating a measurement of the electrode impedance. The 'A' and 'B' electrodes of each output stage may be selectively shorted through a high or low resistance in order to discharge the output coupling capacitors.

Cochlear electrode array with positioning stylet

Abstract: An implantable electrode array, adapted for insertion into either a left or right cochlea, assumes a spiral shape so as to hug the modiolar wall of the cochlea after insertion into the cochlea. All of the electrode contacts are spaced apart along one edge or side of the array, termed the "medial side", which medial side resides on the inside of the spiral. The electrode contacts are thus positioned in close proximity to the modiolar wall, closest to the ganglion cells that are to be stimulated by the electrode array. A positioning stylet made from a suitable memory wire is inserted into a longitudinal channel of the array. The stylet is made from memory wire and has properties selected to return to a desired memory spiral shape at or near body temperature (e.g., approximately 37° C. or 98.6° F.). The positioning stylet is cooled and bent as needed to assume a relatively straight, or non-spiral shape. While relatively straight, the stylet is slidably inserted into the longitudinal channel of the electrode array. The electrode array is then inserted into the cochlea in conventional manner. As the stylet within the electrode array warms to body temperature, it returns to its spiral memory shape, thereby causing the electrode array to also assume a spiral shape, thus positioning the electrode contacts of the electrode array against the modiolar wall.

Cochlear electrode with drug delivery channel and method of making same

Abstract: An electrode array suitable for insertion into the cochlea has a drug delivery channel therein. In a preferred embodiment, electrical stimuli may be applied near the modiolar wall of the cochlea via spaced-apart electrode contacts embedded along a front edge of a flexible carrier, which flexible carrier comprises the body of the electrode array. The front edge, and hence the electrode contacts, may be held against the modiolar wall by a flexible positioner placed on the back side of the flexible carrier. Drugs may be delivered deep into the cochlea through the drug delivery channel that passes longitudinally through the center of the flexible carrier. In an alternative embodiment, the drug delivery channel may be included within the positioner.

Tongue placed tactile output device

Abstract: A mouth stabilized electrode array allows spatially encoded data to be tactily impressed upon the tongue providing an alternative to conventional visual pathways with a more compact size, lower power usage and more convenient apparatus.

Cochlear electrode array with electrode contacts on medial side

Abstract: An implantable electrode array (30), adapted for insertion into a human cochlea, provides improved stability of electrode contact direction. In-line electrodes (32) are spaced-apart along one side of a flexible carrier. The structure of the electrode array facilitates bending of the array with the electrode contacts on the inside of the bend, yet deters flexing or twisting of the array in other directions. The electrode contacts preferably are each made from two strips of metal (210, 220), arranged in a 'T' shape (top view). During assembly, all of the 'T' strips are held in position on an iron sheet (100). Two wire bundles (202, 203) are formed that pass along each side of each 'T'. The leg of each 'T' is folded over to pinch at least one of the wires from one of the wire bundles therebetween. This pinched wire is then resistance welded to the strip. The sides of the 'T' are then folded up. In one embodiment, the sides touch or nearly touch to form a 'Δ' shape (FIG. 5A). In another embodiment, the sides are directed upwards to form a 'U' shape (FIG. 6B). The wire bundles going to more distal electrodes pass through The 'Δ' or 'U' and are engaged thereby. A flexible carrier (36), made from, e.g., silicone rubber, is molded over and around the wire bundles and folded electrode T's, preferably in a slightly curved shape. The iron sheet is chemically etched away, leaving an array of spaced-apart electrode contact areas along one edge of the flexible carrier, each of which is electrically attached to at least one wire which passes through the carrier. In one embodiment, soft shoulders (70) or bumps or ridges are formed in between each electrode contact. A soft tip (37), which in some embodiments may be enlarged into a ball (37'), and which is made from a material that is softer than the flexible carrier, is formed at a distal end of the flexible carrier (36).

An apparatus for controlling the generation of electric fields

Abstract: An apparatus (60) according to the present invention includes a voltage generator (1) for generating brief voltage pulses for the impression of voltage on electrodes (6, 15, 16, 24) included in the apparatus, and a measurement unit (50) which is coupled to the electrodes. These are designed to be secured at or inserted in tissue in a restricted region of a human or an animal in order therebetween to form electric fields in the tissue. The measurement unit (50) is disposed to determine the impedance between the electrodes which is substantially determined by the electric properties of the tissue which is located between the electrodes. A registration and calculator device (10) forms a control unit which, based on the impedance determined by the measurement unit, controls the output voltage of the voltage generator such that the electric field which is formed in the tissue always has a predetermined value. The treatment with the electric field realizes a perforation of cell membranes in the tissue which thereby permits the passage of substances fed to the body (e.g. cytostatic or genetic material).

Driving strategy for non-parallel arrays of electostatic actuators sharing a common electrode

Abstract: An electrostatic actuator array having at least one cell, in which the individual cells share a common electrode. Each cell includes first and second electrodes separated by a distance and having a moveable diaphragm mounted there between for conducting a voltage potential thereto. One of the pair is moveable with respect to the other, and the pair are positioned to move upon application of a voltage potential thereto by electrodes attached thereto. A voltage potential producing an alternate polarity field generated from a single DC power supply is selectively provided to the electrodes to cause the movement. The preferred signals from the power supply are uni-polar square wave signals, preferably deriving the alternate polarity field from a DC current having time allocation of signals to present alternating fields to each actuator. The individual cells are configured in an actuator array wherein some cells operate out of phase with adjoining cells. The plurality of actuation cells equals n, having 2n electrodes, where n is an integer of at least 2. A preferred actuator array comprises n actuation cells working out of phase with 2n electrodes driven with n+1 unipolar signals.

Inflatable cochlear electrode array and method of making same

Abstract: An inflatable cochlear electrode array adapted for insertion into a human cochlear includes a flexible carrier on which a multiplicity of spaced-apart electrode contacts are carried, preferably along one side, e.g., a medial side, of the carrier. The flexible carrier also includes an inflatable compartment or section. In one embodiment, the inflatable section is located at the distal tip of the electrode array on a side of the flexible carrier that is opposite the electrode contacts. In another embodiment, the inflatable compartment or section is located along at least one half of the full length of the flexible carrier, forming a spine. In either embodiment, the electrode is readily inserted into the cochlea to a desired depth while the inflatable compartment or section remains in a deflated state. Thereafter, a desired modiolus-hugging position is achieved by inflating the inflatable compartment or section by injecting therein a suitable biocompatible fluid. A method of making an inflatable cochlear electrode is also disclosed.

Electro-stimulation apparatus using electrode matrix and a counter electrode

Abstract: An electro-stimulation apparatus comprises an electrode system for measuring local electrical impedance. The electrode system includes a multitude of electrode pads and a counter electrode held at a reference voltage. The electrode pads and the counter electrode are assembled in an electrode unit. A particular embodiment of the electro-stimulation apparatus comprises an electronic circuit including a source group of electrode pads and a sink group of electrode pads and a source conductor for applying a first electrical quantity to electrode pads of the source group. The electronic circuit also includes a sink conductor for receiving a second electrical quantity from electrode pads of the sink group. Switching elements couple individual electrode pads of the source group to the source conductor. Other switching elements couple individual electrode pads of the sink group to the sink conductor.

Method and apparatus for controlling the effect of contact impedence on a galvanic tool in a logging-while-drilling application

Abstract: The present invention describes a method and apparatus to control the effect of contact impedance on a formation resistivity measurement during a logging-while-drilling operation. The control of contact impedance is accomplished by maintaining a substantially zero difference in potential between two monitor electrodes positioned on the resistivity logging tool near a current electrode. The tool can employ a ring electrode configuration and/or a button electrode, configuration. The ring electrode configuration incorporates two pairs of ring monitor electrodes on each side of a ring current electrode. The button electrode configuration incorporates. a monitor electrode, surrounded by a current electrode, surrounded by a second monitor electrode. Insulation gaps are positioned between each electrode to separate the electrodes. A variable current is supplied to the current electrode in each configuration to maintain the same potential at each monitor electrode. The effect of contact impedance is controlled through maintaining the same potential at each monitor electrode.

RF Electrode array for low-rate collagen shrinkage in capsular shift procedures and methods of use

Abstract: Methods and apparatus are provided for an achieving low-rate collagen shrinkage using an electrode array comprising an elongated insulator strip having at least one pair of spaced-apart bi-polar RF electrodes, and a “channeling” disposed on the strip between the bi-polar electrodes to direct the flow of RF current therebetween. The channeling electrode is not directly coupled to the RF power source, but only indirectly through the tissue in contact with the channeling electrode. The apparatus enables low RF power levels (e.g., 0.5 watts to 25 watts) to be applied over time intervals of 5 seconds to 180 seconds to attain low-rate collagen shrinkage by directing or focusing the path of the RF current.

EMG electrode array

Abstract: An electrode array for collecting surface electromyographic (EMG) signals from a patient consists of 63 electrically conductive electrodes supported in a non-conductive, flexible pad in a predetermined pattern of nine rows and seven columns of equally spaced electrodes. The flexible pad allows the electrode array to conform to the external curvature of the patient, while the 9x7 rectangular array of electrodes provides a unique pattern related to the configuration of underlying muscle groups of the patient. This allows the sensor pad to be uniquely positioned relative to the patient's anatomy and to provide signals representative of the muscle activity, which can then be electronically displayed in a corresponding pattern, for evaluation by the attending physician.

Method and apparatus for concentrating and/or positioning particles or cells

Abstract: A method for concentrating and/or positioning and/or separating particles or cells comprises placing a liquid medium containing the particles and/or cells over a surface having an electrode array associated with the surface, applying an alternating voltage to the electrode array to create an electric field above the surface within the medium to repel the particles or cells from the electrode array and thereby levitate the particles or cells above the surface, within the medium, by negative dielectrophoresis, and heating the liquid medium so as to cause convection currents to circulate within the medium which concentrate or relocate the levitated cells within the medium. Apparatus for concentrating and/or positioning and/or separating particles or cells are also disclosed.