Successful monitoring of the condition of stimulation electrodes is critical for maintaining chro... more Successful monitoring of the condition of stimulation electrodes is critical for maintaining chronic device performance for neural stimulation. As part of pre-clinical safety testing in preparation for a visual prostheses clinical trial, we evaluated the stability of the implantable devices and stimulation electrodes using a combination of current pulsing in saline and in canine visual cortex. Specifically, in saline we monitored the stability and performance of 3000 μm2 geometric surface area activated iridium oxide film (AIROF) electrodes within a wireless floating microelectrode array (WFMA) by measuring the voltage transient (VT) response through reverse telemetry. Eight WFMAs were assessed in vitro for 24 days, where n = 4 were pulsed continuously at 80 μA (16 nC/phase) and n = 4 remained in solution with no applied stimulation. Subsequently, twelve different WFMAs were implanted in visual cortex in n = 3 canine subjects (4 WFMAs each). After a 2-week recovery period, half of t...
ABSTRACT: Sensors embedded in structural composites have been a topic of research in recent years... more ABSTRACT: Sensors embedded in structural composites have been a topic of research in recent years. Embedded sensors can be used to monitor and optimize the manufacturing process, to monitor performance during use, and for structural health monitoring in highperformance applications. For several years, embedded optical fibers were the predominant type of sensor. There are well-known reasons that optical fiber sensors have not yet been fully embraced in industry including the cost of equipment and sensors, the fragility of the optical fiber itself, and the need to provide ingress and egress from the structure. Recent work by the authors and others has produced prototype wireless electronic sensors of various types that address these shortcomings. The US Office of Naval Research is funding a multidisciplinary
IEEE Antennas and Propagation Society International Symposium. Transmitting Waves of Progress to the Next Millennium. 2000 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.00CH37118)
... The microcoil couples to an extracorporeal transmitter coil using a transcuf.aneous inductive... more ... The microcoil couples to an extracorporeal transmitter coil using a transcuf.aneous inductive link. ... switchmode resonant drivers can be used to drive the transmitter coil, but these topologies are often better suited for circuits in which significant power transfer must take place. ...
2021 43rd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), 2021
Peripheral nerve stimulation is a commonly used method for assisting movements after spinal cord ... more Peripheral nerve stimulation is a commonly used method for assisting movements after spinal cord injury, stroke, traumatic brain injury, and other types of neurological damage or dysfunction. There are many different patterns of electrical stimulation used to accomplish movement. And so, our study investigated stimulation with a wireless floating microelectrode array (WFMA) in comparison to previously reported data on functional electrical stimulation. To determine the effect on hindlimb movement, we tested a range of frequencies and pulse widths using WFMAs that were implanted in the rat sciatic nerve for 38 weeks. Frequencies between 1 and 50 Hz did not change the minimum current amplitude required to elicit movement in the hindlimb. Increasing pulse width from 57.2 to 400.4 µs decreased the minimum current required but had an associated increase in total charge applied per pulse. Overall, the WFMA provides a stable wireless peripheral nerve interface suitable for functional electrical stimulation. Clinical Relevance-This work establishes the efficacy of various stimulation parameters for controlling movement with a wireless peripheral nerve stimulator.
The possibility of engineering, testing, and deploying a cybernetic interface to the visual areas... more The possibility of engineering, testing, and deploying a cybernetic interface to the visual areas of the human brain has inspired scientists, biomedical engineers, clinicians, and science fiction writers. Implemented as a cortical visual prosthesis, visual perception might be provided to individuals with blindness. Based upon pioneering work in the late 1960’s, and the development of significant technology throughout the remainder of the twentieth century, the Intracortical Visual Prosthesis (ICVP) is being planned for clinical trial. Autonomous, wireless, 16-channel stimulator modules will be used to tile the dorsolateral surface of the human occipital lobe. Each module will contain 16 intracortical electrodes that penetrate the cortical surface and provide simulation currents to visual processing areas of the brain. Through the use of spatial and temporal integration, the expectation is that the brain will convert the artificial visual information into useful visual perceptions. While it is not expected that the ICVP will produce normal vision, prior work strongly suggests that the artificial visual perception may notably enhance the user’s ability to recognize objects and navigate, and improve overall quality of life.
Objective. Maximizing the stability of implanted neural interfaces will be critical to developing... more Objective. Maximizing the stability of implanted neural interfaces will be critical to developing effective treatments for neurological and neuromuscular disorders. Our research aims to develop a stable neural interface using wireless communication and intrafascicular microelectrodes to provide highly selective stimulation of neural tissue.Approach. We implanted a wireless floating microelectrode array into the left sciatic nerve of six rats. Over a 38-week implantation period, we recorded stimulation thresholds and movements evoked at each implanted electrode. We also tracked each animal's response to sensory stimuli and performance on two different walking tasks.Main Results. Presence of the microelectrode array inside the sciatic nerve did not cause any obvious motor or sensory deficits in the hindlimb. Visible movement in the hindlimb was evoked by stimulating the sciatic nerve with currents as low as 4.1 μA. Thresholds for most of the 96 electrodes we implanted were below 20 μA, and predictable recruitment of plantar flexion and dorsiflexion was achieved by stimulating rat sciatic nerve with the intrafascicular microelectrode array. Further, motor recruitment patterns for each electrode did not change significantly throughout the study.Significance. Incorporating wireless communication and a low-profile neural interface facilitated highly stable motor recruitment thresholds and fine motor control in the hindlimb throughout an extensive 9.5-month assessment in rodent peripheral nerve. Results of this study indicate that use of the wireless device tested here could be extended to other applications requiring selective neural stimulation and chronic implantation.
Translational Vision Science & Technology, 2020
Notice: Changes introduced as a result of publishing processes such as copy-editing and formattin... more Notice: Changes introduced as a result of publishing processes such as copy-editing and formatting may not be reflected in this document. For a definitive version of this work, please refer to the published source.
Public reporting burden for this collection of information is estimated to average 1 hour per res... more Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015
Here, we report on chronic in-vivo testing of a 16-channel wireless floating microelectrode array... more Here, we report on chronic in-vivo testing of a 16-channel wireless floating microelectrode array (WFMA) in a rat sciatic nerve model. Muscle threshold currents, charge injection levels, and charge density were monitored for electrodes of two WFMA devices implanted into animal subjects over a five month period. This type of wireless stimulation device could eliminate problems associated with percutaneous connectors for a variety of neural prostheses and other medical devices.
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015
Functional stability and in-vivo reliability are significant factors determining the longevity of... more Functional stability and in-vivo reliability are significant factors determining the longevity of a neural interface. In this ongoing study, we test the performance of a wireless floating microelectrode array (WFMA) over a period of 143 days. The topography of the microelectrodes has allowed for selective stimulation of different fascicles of the rat sciatic nerve. We confirmed that motor evoked thresholds remain stable over time and that the nerve stimulation charges were within tissue safety limits. Importantly, motor evoked responses were elicited at threshold currents in fully awake animals without causing pain or discomfort. These data validate the use of the WFMA system for intraneural interfacing of peripheral nerves for neuroprosthetic and bioelectronics medical applications.
Proceedings of the 20th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. Vol.20 Biomedical Engineering Towards the Year 2000 and Beyond (Cat. No.98CH36286)
The goal of this project is to develop complete clinical systems for the application of functiona... more The goal of this project is to develop complete clinical systems for the application of functional electrical stimulation to alleviate disabilities and morbidity associated with musculoskeletal paralysis and atrophy. Over the past 8 years, the authors have designed, built and successfully tested in animals the first device in a new class of implantable electronic interfaces with nerve and muscle. BIONs
2015 7th International IEEE/EMBS Conference on Neural Engineering (NER), 2015
A total of thirteen individuals were interviewed and asked to describe their experiences of parti... more A total of thirteen individuals were interviewed and asked to describe their experiences of participating in a cortical vision implant study conducted by William Dobelle between 2000 and 2005. The transcripts from the interviews were analyzed using MAXQDA software and themes that resulted from the interviews such as motivation to participate, sensory substitution expectations, decision-making process, experience of artificial vision and functional use of artificial vision is described in depth. Emotional experiences of participating in the study result in ethical and psychological implications for future research.
2015 7th International IEEE/EMBS Conference on Neural Engineering (NER), 2015
Wireless stimulation of neural tissue could enable many emerging neural prosthesis designs, and e... more Wireless stimulation of neural tissue could enable many emerging neural prosthesis designs, and eliminate problems associated with percutaneous wires and connectors. Our laboratory has developed a 16-channel wireless floating microelectrode array (WFMA) for chronic implantation. Here, we report on its first use within in-vivo experiments, using a rat sciatic nerve model. Stimulus currents and associated muscular movements were determined for electrodes of two WFMA devices implanted into four animal subjects.
The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society
AbstractThe charge-injection currents of AIROF (activated iridium oxide film) microelectrodes, w... more AbstractThe charge-injection currents of AIROF (activated iridium oxide film) microelectrodes, which are subjected to charge-balanced biphasic pulsing or monophasic current pulsing, have to be limited such that the anodic and cathodic voltage excursions are kept ...
Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439)
Absrracf-The capability to use the same microelectrode for electrical stimulation of neurons, as ... more Absrracf-The capability to use the same microelectrode for electrical stimulation of neurons, as well as for neural signal recording from neurons in the vicinity of the electrode, has historically been a goal of neuroscientists. During, and after, stimulation the stimulus artifact effectively disables the recording system until the residual effects of the artifact have dissipated. The only practical way to successfully record neural signals in the presence of stimulus pulses is to fully integrate the constant-current hi-directional stimulation circuitry with a specialized bioelectric recording amplifier on the same electronic chip. This is because post-stimulus electrode polarization recovery, amplifier blanking, and low-noise amplifier circuitry must be intimately tied to the stimulus circuitry, and such functional integration can only be obtained by implementing the combined circuitry as one application specific integrated circuit (ASIC) design. Toward this goal, a topology for a neural recording amplifier with rapid recovery characteristics was designed and tested using discrete components, and was successfully used to suppress stimulation artifacts generated by a nearby electrode in vitro.
Proceedings of the 15th Annual International Conference of the IEEE Engineering in Medicine and Biology Societ
Neural prostheses are electronic devices that restore sensory or motor function by transmitting s... more Neural prostheses are electronic devices that restore sensory or motor function by transmitting signals directly between electronic circuits and the living nervous system. We are developing a family of implantable electronic moduIes that can be used in a variety of combinations both to stimulate individual nerves and muscles (microstimulators), and to measure and transmit information from the limb to the
2006 International Conference of the IEEE Engineering in Medicine and Biology Society, 2006
The goal of cortical neuroprosthesis researchers of last four decades is to develop a practical i... more The goal of cortical neuroprosthesis researchers of last four decades is to develop a practical intracortical visual prosthesis device. Although the concept of such a system seems straightforward, details of its configuration remain undefined. Knowledge of how the human visual system will respond to artificially-induced visually-based input is sparse. Combined with technological limitations, these have hindered the progress in developing a practical intracortical visual prosthesis device. The long-term objective of this research is to develop a continuously wearable intracortical visual prosthesis device. Earlier studies have used relatively small numbers of cortical electrodes, and these have been insufficient to generate an integrated visual perception. Surgical difficulties also complicate problem. A prototype visual prosthesis system needs to be adaptable to varying stimulation, image processing, and user interface needs. It also has the obvious requirement portability, implying extremely low power consumption and low weight so that the system can be used outside the confinement of a lab. We feel that available technology has sufficiently advanced to develop a first-generation intracortical visual prosthesis device. In this paper we propose some solutions to the challenges for developing this visual prosthesis device using existing technologies.
Successful monitoring of the condition of stimulation electrodes is critical for maintaining chro... more Successful monitoring of the condition of stimulation electrodes is critical for maintaining chronic device performance for neural stimulation. As part of pre-clinical safety testing in preparation for a visual prostheses clinical trial, we evaluated the stability of the implantable devices and stimulation electrodes using a combination of current pulsing in saline and in canine visual cortex. Specifically, in saline we monitored the stability and performance of 3000 μm2 geometric surface area activated iridium oxide film (AIROF) electrodes within a wireless floating microelectrode array (WFMA) by measuring the voltage transient (VT) response through reverse telemetry. Eight WFMAs were assessed in vitro for 24 days, where n = 4 were pulsed continuously at 80 μA (16 nC/phase) and n = 4 remained in solution with no applied stimulation. Subsequently, twelve different WFMAs were implanted in visual cortex in n = 3 canine subjects (4 WFMAs each). After a 2-week recovery period, half of t...
ABSTRACT: Sensors embedded in structural composites have been a topic of research in recent years... more ABSTRACT: Sensors embedded in structural composites have been a topic of research in recent years. Embedded sensors can be used to monitor and optimize the manufacturing process, to monitor performance during use, and for structural health monitoring in highperformance applications. For several years, embedded optical fibers were the predominant type of sensor. There are well-known reasons that optical fiber sensors have not yet been fully embraced in industry including the cost of equipment and sensors, the fragility of the optical fiber itself, and the need to provide ingress and egress from the structure. Recent work by the authors and others has produced prototype wireless electronic sensors of various types that address these shortcomings. The US Office of Naval Research is funding a multidisciplinary
IEEE Antennas and Propagation Society International Symposium. Transmitting Waves of Progress to the Next Millennium. 2000 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.00CH37118)
... The microcoil couples to an extracorporeal transmitter coil using a transcuf.aneous inductive... more ... The microcoil couples to an extracorporeal transmitter coil using a transcuf.aneous inductive link. ... switchmode resonant drivers can be used to drive the transmitter coil, but these topologies are often better suited for circuits in which significant power transfer must take place. ...
2021 43rd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), 2021
Peripheral nerve stimulation is a commonly used method for assisting movements after spinal cord ... more Peripheral nerve stimulation is a commonly used method for assisting movements after spinal cord injury, stroke, traumatic brain injury, and other types of neurological damage or dysfunction. There are many different patterns of electrical stimulation used to accomplish movement. And so, our study investigated stimulation with a wireless floating microelectrode array (WFMA) in comparison to previously reported data on functional electrical stimulation. To determine the effect on hindlimb movement, we tested a range of frequencies and pulse widths using WFMAs that were implanted in the rat sciatic nerve for 38 weeks. Frequencies between 1 and 50 Hz did not change the minimum current amplitude required to elicit movement in the hindlimb. Increasing pulse width from 57.2 to 400.4 µs decreased the minimum current required but had an associated increase in total charge applied per pulse. Overall, the WFMA provides a stable wireless peripheral nerve interface suitable for functional electrical stimulation. Clinical Relevance-This work establishes the efficacy of various stimulation parameters for controlling movement with a wireless peripheral nerve stimulator.
The possibility of engineering, testing, and deploying a cybernetic interface to the visual areas... more The possibility of engineering, testing, and deploying a cybernetic interface to the visual areas of the human brain has inspired scientists, biomedical engineers, clinicians, and science fiction writers. Implemented as a cortical visual prosthesis, visual perception might be provided to individuals with blindness. Based upon pioneering work in the late 1960’s, and the development of significant technology throughout the remainder of the twentieth century, the Intracortical Visual Prosthesis (ICVP) is being planned for clinical trial. Autonomous, wireless, 16-channel stimulator modules will be used to tile the dorsolateral surface of the human occipital lobe. Each module will contain 16 intracortical electrodes that penetrate the cortical surface and provide simulation currents to visual processing areas of the brain. Through the use of spatial and temporal integration, the expectation is that the brain will convert the artificial visual information into useful visual perceptions. While it is not expected that the ICVP will produce normal vision, prior work strongly suggests that the artificial visual perception may notably enhance the user’s ability to recognize objects and navigate, and improve overall quality of life.
Objective. Maximizing the stability of implanted neural interfaces will be critical to developing... more Objective. Maximizing the stability of implanted neural interfaces will be critical to developing effective treatments for neurological and neuromuscular disorders. Our research aims to develop a stable neural interface using wireless communication and intrafascicular microelectrodes to provide highly selective stimulation of neural tissue.Approach. We implanted a wireless floating microelectrode array into the left sciatic nerve of six rats. Over a 38-week implantation period, we recorded stimulation thresholds and movements evoked at each implanted electrode. We also tracked each animal's response to sensory stimuli and performance on two different walking tasks.Main Results. Presence of the microelectrode array inside the sciatic nerve did not cause any obvious motor or sensory deficits in the hindlimb. Visible movement in the hindlimb was evoked by stimulating the sciatic nerve with currents as low as 4.1 μA. Thresholds for most of the 96 electrodes we implanted were below 20 μA, and predictable recruitment of plantar flexion and dorsiflexion was achieved by stimulating rat sciatic nerve with the intrafascicular microelectrode array. Further, motor recruitment patterns for each electrode did not change significantly throughout the study.Significance. Incorporating wireless communication and a low-profile neural interface facilitated highly stable motor recruitment thresholds and fine motor control in the hindlimb throughout an extensive 9.5-month assessment in rodent peripheral nerve. Results of this study indicate that use of the wireless device tested here could be extended to other applications requiring selective neural stimulation and chronic implantation.
Translational Vision Science & Technology, 2020
Notice: Changes introduced as a result of publishing processes such as copy-editing and formattin... more Notice: Changes introduced as a result of publishing processes such as copy-editing and formatting may not be reflected in this document. For a definitive version of this work, please refer to the published source.
Public reporting burden for this collection of information is estimated to average 1 hour per res... more Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015
Here, we report on chronic in-vivo testing of a 16-channel wireless floating microelectrode array... more Here, we report on chronic in-vivo testing of a 16-channel wireless floating microelectrode array (WFMA) in a rat sciatic nerve model. Muscle threshold currents, charge injection levels, and charge density were monitored for electrodes of two WFMA devices implanted into animal subjects over a five month period. This type of wireless stimulation device could eliminate problems associated with percutaneous connectors for a variety of neural prostheses and other medical devices.
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015
Functional stability and in-vivo reliability are significant factors determining the longevity of... more Functional stability and in-vivo reliability are significant factors determining the longevity of a neural interface. In this ongoing study, we test the performance of a wireless floating microelectrode array (WFMA) over a period of 143 days. The topography of the microelectrodes has allowed for selective stimulation of different fascicles of the rat sciatic nerve. We confirmed that motor evoked thresholds remain stable over time and that the nerve stimulation charges were within tissue safety limits. Importantly, motor evoked responses were elicited at threshold currents in fully awake animals without causing pain or discomfort. These data validate the use of the WFMA system for intraneural interfacing of peripheral nerves for neuroprosthetic and bioelectronics medical applications.
Proceedings of the 20th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. Vol.20 Biomedical Engineering Towards the Year 2000 and Beyond (Cat. No.98CH36286)
The goal of this project is to develop complete clinical systems for the application of functiona... more The goal of this project is to develop complete clinical systems for the application of functional electrical stimulation to alleviate disabilities and morbidity associated with musculoskeletal paralysis and atrophy. Over the past 8 years, the authors have designed, built and successfully tested in animals the first device in a new class of implantable electronic interfaces with nerve and muscle. BIONs
2015 7th International IEEE/EMBS Conference on Neural Engineering (NER), 2015
A total of thirteen individuals were interviewed and asked to describe their experiences of parti... more A total of thirteen individuals were interviewed and asked to describe their experiences of participating in a cortical vision implant study conducted by William Dobelle between 2000 and 2005. The transcripts from the interviews were analyzed using MAXQDA software and themes that resulted from the interviews such as motivation to participate, sensory substitution expectations, decision-making process, experience of artificial vision and functional use of artificial vision is described in depth. Emotional experiences of participating in the study result in ethical and psychological implications for future research.
2015 7th International IEEE/EMBS Conference on Neural Engineering (NER), 2015
Wireless stimulation of neural tissue could enable many emerging neural prosthesis designs, and e... more Wireless stimulation of neural tissue could enable many emerging neural prosthesis designs, and eliminate problems associated with percutaneous wires and connectors. Our laboratory has developed a 16-channel wireless floating microelectrode array (WFMA) for chronic implantation. Here, we report on its first use within in-vivo experiments, using a rat sciatic nerve model. Stimulus currents and associated muscular movements were determined for electrodes of two WFMA devices implanted into four animal subjects.
The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society
AbstractThe charge-injection currents of AIROF (activated iridium oxide film) microelectrodes, w... more AbstractThe charge-injection currents of AIROF (activated iridium oxide film) microelectrodes, which are subjected to charge-balanced biphasic pulsing or monophasic current pulsing, have to be limited such that the anodic and cathodic voltage excursions are kept ...
Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439)
Absrracf-The capability to use the same microelectrode for electrical stimulation of neurons, as ... more Absrracf-The capability to use the same microelectrode for electrical stimulation of neurons, as well as for neural signal recording from neurons in the vicinity of the electrode, has historically been a goal of neuroscientists. During, and after, stimulation the stimulus artifact effectively disables the recording system until the residual effects of the artifact have dissipated. The only practical way to successfully record neural signals in the presence of stimulus pulses is to fully integrate the constant-current hi-directional stimulation circuitry with a specialized bioelectric recording amplifier on the same electronic chip. This is because post-stimulus electrode polarization recovery, amplifier blanking, and low-noise amplifier circuitry must be intimately tied to the stimulus circuitry, and such functional integration can only be obtained by implementing the combined circuitry as one application specific integrated circuit (ASIC) design. Toward this goal, a topology for a neural recording amplifier with rapid recovery characteristics was designed and tested using discrete components, and was successfully used to suppress stimulation artifacts generated by a nearby electrode in vitro.
Proceedings of the 15th Annual International Conference of the IEEE Engineering in Medicine and Biology Societ
Neural prostheses are electronic devices that restore sensory or motor function by transmitting s... more Neural prostheses are electronic devices that restore sensory or motor function by transmitting signals directly between electronic circuits and the living nervous system. We are developing a family of implantable electronic moduIes that can be used in a variety of combinations both to stimulate individual nerves and muscles (microstimulators), and to measure and transmit information from the limb to the
2006 International Conference of the IEEE Engineering in Medicine and Biology Society, 2006
The goal of cortical neuroprosthesis researchers of last four decades is to develop a practical i... more The goal of cortical neuroprosthesis researchers of last four decades is to develop a practical intracortical visual prosthesis device. Although the concept of such a system seems straightforward, details of its configuration remain undefined. Knowledge of how the human visual system will respond to artificially-induced visually-based input is sparse. Combined with technological limitations, these have hindered the progress in developing a practical intracortical visual prosthesis device. The long-term objective of this research is to develop a continuously wearable intracortical visual prosthesis device. Earlier studies have used relatively small numbers of cortical electrodes, and these have been insufficient to generate an integrated visual perception. Surgical difficulties also complicate problem. A prototype visual prosthesis system needs to be adaptable to varying stimulation, image processing, and user interface needs. It also has the obvious requirement portability, implying extremely low power consumption and low weight so that the system can be used outside the confinement of a lab. We feel that available technology has sufficiently advanced to develop a first-generation intracortical visual prosthesis device. In this paper we propose some solutions to the challenges for developing this visual prosthesis device using existing technologies.
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