The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Advances in microfabrication have allowed the integration of large numbers of electrodes onto one platform. The small size and high channel density of these microelectrode arrays which promise improved performance of a neural prosthesis also complicate the design of an inductive link to achieve efficient powering and communication with the implant. Stimulating or recording with many channels requires...
We have developed a multichannel electrogmyography sensor system capable of receiving and processing signals from up to 32 implanted myoelectric sensors (IMES). The appeal of implanted sensors for myoelectric control is that electromyography (EMG) signals can be measured at their source providing relatively cross-talk-free signals that can be treated as independent control sites. An external telemetry...
As a component of the RP2009 project, the IMES system has emerged as a strong candidate for extracting naturally-occurring control signals to be used for providing functional control of an upper body artificial limb. In earlier publications, we described various elements of this system as they were being researched and developed. Presently, the system has matured to a level for which it is now appropriate...
We present updated progress on the design, construction and testing of an upper-extremity prosthesis control system based on implantable myoelectric sensors. The miniature injectable implant consists of a single silicon chip packaged with transmit and receive coils. Preparation for human implantation of the IMES system is underway. As part of this process, critical design improvements in the IMES...
Activated Iridium Oxide Film (AIROF) microelectrodes are being proposed for use in multiple neural prosthesis designs because they are characterized by a high charge-delivery capacity. Implicit in their use, is the restriction of limiting the electrode polarization within limits that do not initiate water electrolysis at the electrode/electrolyte interface. These limits, the so-called ";water...
Visual prosthesis devices are being developed to restore vision for those with blindness. Researchers working in the field of visual prosthesis are taking different approaches to develop a practical device. Some are targeting the retina for stimulation, whereas at least one group is targeting the optical nerve, and our laboratory is developing a system for the visual cortex. To estimate the kind of...
Earlier experiments in the field of cortical visual prosthesis have shown the possibility of generation of phosphenes. Experiments have been performed with different types of electrodes, researchers have found the stimulation parameters required to elicit a phosphene and they have shown the possibility of targeting different areas of visual cortex to elicit phosphenes. Experiments have not been conducted...
Activated iridium oxide film (AIROF) microelectrodes have high charge delivery capacity within polarization limits that don't initiate water electrolysis at the electrode/electrolyte interface. These limits, the so-called "water window," are used to ensure that the AIROF electrodes can deliver charge reversibly in various electrolyte environments. However, strictly observing these limits...
Researchers have been trying to develop a visual prosthesis device for last four decades. Earlier efforts were hindered by the shortcomings of technology. Recent technological advancements have improved the likelihood of developing a practical intracortical visual prosthesis device that can be implanted in blind human subjects. The requirement of such a device is to operate in real-time for a high...
Neuroscientists have widely used metal microelectrodes inserted into the cortex to record neural signals from, and provide electrical stimulation to, neural tissue for many years. Recently, the demand for implanting electrode arrays within the cortex, for both stimulation and recording, has rapidly increased. We are developing Active-floating-micro-electrode-arrays (AFMA) that are intended for use...
Cyclic voltametry and recording of stimulation electrode voltage excursions are two critical methods of measurement for understanding the performance of implantable electrodes. Because implanted electrodes cannot easily be replaced, it is necessary to have an a-priori understanding of an electrode's implanted performance and capabilities. In-vitro exhaustive tests are often needed to quantify an electrodes...
Capacitive coupling within high-density microelectrode arrays can degrade neural recording signal or disperse neural stimulation current. Material deterioration in a chronically implanted neural stimulation/recording system can cause such an undesired effect. We present a simple method with an iterative algorithm to quantify the cross-coupling capacitance, in-situ
With the availability of modern application specific integrated circuit (ASIC) design tools, simulation packages, and low-cost commercial silicon foundry processes, it is becoming increasingly easy for any laboratory, or small company, to develop a custom ASIC. For stimulation, as well as recording, chips that perform specialized functions can be designed, fabricated, and tested within a time period...
We present progress on the design and testing of an upper-extremity prosthesis control system based on implantable myoelectric sensors. The implant consists of a single silicon chip packaged with transmit and receive coils. Forward control telemetry to, and reverse EMG data telemetry from multiple implants has been demonstrated
Neuroscientists have widely used metal microelectrodes inserted into the cortex to record neural signals from, and provide electrical stimulation to, neural tissue for many years. Recently, the demand for implanting electrode arrays within the cortex, for both stimulation and recording, has rapidly increased. We are developing Active-floating-micro-electrode-arrays (AFMA) that are intended for use...
Cyclic voltametry and recording of stimulation electrode voltage excursions are two critical methods of measurement for understanding the performance of implantable electrodes. Because implanted electrodes cannot easily be replaced, it is necessary to have an a-priori understanding of an electrode's implanted performance and capabilities. In-vitro exhaustive tests are often needed to quantify an electrodes...
Neuroscientists have widely used metal microelectrodes inserted into the cortex to record neural signals from, and provide electrical stimulation to, neural tissue for many years. Recently, the demand for implanting electrode arrays within the cortex, for both stimulation and recording, has rapidly increased. We are developing Active-floating-micro-electrode-arrays (AFMA) that are intended for use...
Cyclic voltametry and recording of stimulation electrode voltage excursions are two critical methods of measurement for understanding the performance of implantable electrodes. Because implanted electrodes cannot easily be replaced, it is necessary to have an a-priori understanding of an electrode's implanted performance and capabilities. In-vitro exhaustive tests are often needed to quantify an electrodes...
The NeuroTalkTM interface, described in a companion paper allows for a standardized method of communication with implanted modules that contain custom application specific integrated circuits (ASIC). Here, we describe an example of one such ASIC that has been designed for use in a visual prosthesis. The ASIC is small enough to be incorporated within a 16-channel multielectrode stimulation array implanted...
Activated Iridium Oxide Film (AIROF) microelectrodes are thought to be well-suited for neural stimulation of the cortex because they can sustain high charge capacity (about ten times higher than Pt microelectrodes) when characterized in phosphate-buffered saline (PBS) or other high ionic strength electrolytes. However, it is known that their capacity diminishes after they are implanted in vivo. It...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.