Under a grant funded by the National Institutes of Health Institute on Deafness and Other Communication Disorders (NIDCD), researchers are developing a new laser that stimulates human nerve tissue. The project, developed by Vixar, includes evaluating the devices for incorporation into optically based neuroprostheses, such as cochlear implants.
The researchers will develop a miniaturized infrared (IR) laser that will form the basis of IR neurostimulation prostheses with dramatically improved spatial selectivity. The small size, power, and efficiency of the device would make possible implantable devices that can overcome some of the issues of electrically based stimulation devices, for instance, current spreading that limits the number of independent channels in cochlear implants.
In the example of cochlear implants, this innovation would improve the quality of the implants, particularly in noisy environments or in appreciating music.
Infrared neural stimulation (INS) is a novel technology that holds promise for increasing the number of independent channels in neuroprostheses. A complementary technology to electrical stimulation, INS has been used in the cochlea, vestibular system, peripheral nerve, brain, and other excitable tissues to provide precisely targeted, artifact-free stimulation of nerves.
The long-term goal of the proposed research is to improve the performance of neurostimulation prostheses. For example, while cochlear implants have been very successful in restoring hearing, they still face limitations in terms of their performance in noisy environments or the ability of the user to enjoy music. These challenges are primarily due to the limited number of effective frequency channels resulting from electrical cross-talk between electrodes.
The preliminary feasibility and safety of neuroprostheses based upon INS have been demonstrated by Northwestern University and Lockheed Martin in a variety of pre-clinical trials. However, the practical implementation of INS requires substantial miniaturization, with the key missing piece being an optical source that can be incorporated into an implantable device.
Vertical Cavity Surface Emitting Lasers (VCSELs) hold great promise for providing the combination of size and performance that are required. The Phase I project will therefore establish the feasibility of the VCSEL for meeting the optical power, power efficiency, and physical size requirements. A Phase II project will develop suitable packaging for implantation and perform a proof-of-concept demonstration of efficacy and safety in animals.
Vixar has demonstrated the highest power 1860 nm VCSELs to date, but a gap remains between the status and the requirements for INS. By combining several new design features of the VCSEL, Vixar expects to achieve output power and efficiency that are sufficient for the targeted applications. The Phase I project will therefore establish the feasibility of using a VCSEL device in INS, setting the stage for a Phase II project, which will address thermal management, packaging, and the proof-of-concept.
SOURCE: Vixar Inc