Argus II Retinal Prosthesis System
April 27, 2014

NSF Researcher Develops How-To Guide For DIY Brain-Machine Interfaces

redOrbit Staff & Wire Reports - Your Universe Online

A few decades ago, instruments capable of tapping into a person’s nervous system to help restore movement, sensations or cognitive function seemed impossible. Now, however, the National Science Foundation (NSF) has released a how-to guide for those interested in building their own brain-machine interfaces (BMIs).

Guide author and AAAS Science and Technology Policy Fellow Valerie Thompson recruited the engineers behind the Argus II Retinal Prosthesis System to help walk aspiring BMI developers through the creative process. The Argus II is an artificial retina intended for use by men and women who have lost their vision due to retinitis pigmentosa.

Retinitis pigmentosa is a genetic condition that affects one out of every 4,000 or so people, and early symptoms include night blindness and a gradual progressive loss of peripheral vision. The Argus II system bypasses damaged cells in the eye that typically convert light into electrical signals interpreted by the brain (photoreceptors). It transmits images from a small camera to an implant located in the back of the eye that acts like a photoreceptor.

So how does someone set out creating a device like the Argus II?

“Like any other engineering challenge, building a BMI involves background research, feasibility testing, prototyping and production,” Thompson wrote. “But building a BMI is unique in that engineers must design these devices to seamlessly interface with another complex system: the human nervous system.”

Motivation is essential, she explained. One of the device’s co-creators, Mark Humayun, associate director of research at the USC Doheny Retina Institute, explained that it was his grandmother’s blindness that inspired him to “pursue ophthalmology and biomedical engineering to develop a treatment for patients for whom there was no foreseeable cure.”

Without that motivation, Thompson said, the development of such a device probably would have been too challenging for the engineers to see through to the end. Once the motivation is there, the first step is to determine whether or not a condition is a good fit for a BMI, and the second is to make sure that a mechanical fix is even possible.

In the case of the Argus II, the researchers had to first figure out which parts of the visual pathway were functioning and which were not, and to make sure that there were enough neurons in the eye to be stimulated and transmit nerve impulses. Next, they had to figure out how to simulate photoreceptor activity with artificial electrical stimulation, how to make sure the implant had power, and how to integrate its external components.

The third part of the process, according to Thompson, is to make sure that the devices function cohesively with the human body, and can function effectively in the presence of body fluids and tissues. Next, the engineers need to optimize each component of the device, making them as small as possible and ensuring that it functions well with all other parts of the unit. This process is known as systems-level optimization.

“One of the final steps in building a BMI is getting it into the hands of those who need it,” she continued. “When the initial technology is developed in an academic research setting, this can often mean handing it off to a company that will facilitate manufacturing and manage clinical trials and commercial distribution to patients.”

With the Argus project, the developers conducted clinical trials on the first-generation device in 2002, followed by pilot studies and patent trials for the Argus II in 2006. It was approved by the FDA on February 14, 2013, making it the first visual prosthesis to receive market approval in the US. However, there’s always room for improvement, Thompson said – which itself is the sixth and final step of the brain-machine interface development process.