This project represents an ongoing collaboration between teams at two institutions. As people live longer, blindness caused by degenerative diseases of the retina such as macular degeneration or retinitis pigmentosa is today a major disability among the aging in the developed world. These types of "neural" blindness cannot currently be medically treated in any satisfactory manner. There is now compelling experimental evidence in humans that even when such diseases cause a loss of photoreceptors (i.e., rod and cone cells in the retina), electrical stimulation of the remaining retinal neurons that survive this loss can be used to bypass the damaged tissue and deliver visual information to the brain. This is essentially the same concept that supported the development of the cochlear prosthesis, which has been a fabulous success, restoring hearing to many tens of thousands of deaf patients. The PIs and their respective teams have been working for over 20 years toward the goal of developing a retinal prosthesis to restore truly useful vision to patients in an analogous manner. With prior funding from a number of agencies including NSF, they have created enabling technology for a miniaturized high-density implantable wirelessly-driven neuro-prosthesis package with over 200 individually-addressable channels, which is over three times the inputs and outputs in any current commercially available neurostimulator. The field's ability to create complex integrated circuitry for neurostimulation and/or recording has outpaced the development of long-term implantable packaging, microelectrode array, and assembly technology. If optimized, those technologies would make possible new devices that interface with hundreds of neural tissue sites simultaneously. This is the PI's aim in the current project. The funding will complement existing grants to the PIs and their collaborators, and will allow them to complete development of a new 200+ channel co-fired ceramic signal feed-through disc, to optimize the micro-fabrication process for high-density microelectrode arrays that interface with neural tissue, and to improve the bonding and interconnection processes required to assemble the implant package.
Broader Impacts: The 200+ channel wirelessly-driven implant that will constitute the primary project outcome will have over three times the number of individually-addressable stimulating electrodes now available from any group. This funding will further allow the PI to ready devices for later pre-clinical testing (with anticipated follow-on support from the VA). Project results will be widely disseminated in publications, and by distributing sample devices within the rehabilitation R&D community. The device which is the focus of this project will also be useful in a myriad other future chronically implantable prosthetics, palliative devices, and human-computer interface devices.
This grant proposal sought to develop an advanced device to treat blindness caused by retinal disease, like macular degeneration and retinitis pigmentosa. Our goal was to develop a retinal prosthesis with significantly more stimluation electrodes, which has the potential to improve the quality of vision over devices that are using a smaller number of electrodes. Our accomplishments during the period of this grant enabled us to develop the computer chip and delicate wires to drive more than 256 electrodes, while protecting the electronic system from the destructive salt-water environment of the body. Our 256 electrode system has achieved a more than 4 fold increase in the number of stimluation electrodes compared to any other system in the world, for any type of therapeutic application. Our accomplishments can also be used to treat a wide variety of other diseases that affect the central nervous system, including deafness, Parkinson, chronic pain syndromes, intractable epilepsy, and spinal cord injury. Our technology can also be used to significantly improve the technical approach for a wide range of laboratory experiments in the field of electrical stimluation, which will be helpful toward the development of new devices to treat nervous system disease. The work on this grant also enabled the recruitment of one of our primary engineers to the Carnegie Melon University, where he has established a new laboratory to develop tools for electrical stimluation of the nervous system. In this new laboratory, this researcher is now training his own students who will contribute to future work in this area.