Human-machine mergers promising, but reality yet to live up to hype

Jens Naumann had been blind for 19 years. But in 2002, in a Portuguese hospital, the Canadian, then 39, began seeing flashes of light, then shapes of large objects.
The Utah Electrode Array can "talk" to nerves, telling parts of the body what to do.
Jens Naumann had been blind for 19 years. But in 2002, in a Portuguese hospital, the Canadian, then 39, began seeing flashes of light, then shapes of large objects.

That's because he was the first recipient of a brain implant called the Dobelle Eye.

Biomedical researcher William Dobelle worked for years to wire a tiny camera to a brain implant so people with irreparably damaged eyes might see again. It was an example of work being done in the field of neuroprosthetics, which explores making electronic devices communicate directly with the brain. One of the most common neuroprosthetic devices, the cochlear implant, has already helped nearly 200,000 people with hearing loss.

But technology to restore vision is still in the early development stages. Naumann says the Dobelle Eye implant gave him only rudimentary vision: "It is like seeing in a way, because you did feel a visual awareness."

Still, he could navigate around obstacles, locate objects and, with practice, read block letters 10 centimetres high. He even drove a car — slowly — in a parking lot. Sadly, it didn't last.

"The device was pretty functional for as long as you could baby it and doctor it," Naumann recalls. But after Dobelle's death in 2004, Naumann could not maintain it. The implant is still in his brain, but infections forced removal of the connectors placed in his skull to connect the external camera.

Sixteen patients had the implant, he says, but none had better luck than he did. The device was never approved in the U.S. or Canada — all operations were done in Portugal. Dobelle demonstrated the promise in feeding visual information directly into the brain — but also that was not ready for widespread use.

Neuroprosthetic progress

Researchers are exploring ways to use neuroprosthetics to restore broken communications between the brain and other parts of the body.
It still isn't — but promising work continues in a number of areas.

While Dobelle placed his implant on the surface of the brain, for example, Mohamad Sawan, Canada research chair in smart medical devices and director of the Polystim Neurotechnologies Laboratory at Montreal's Ecole Polytechnique, is working on one with a needle-like probe that enters the cortex to reach the precise area where the optic nerve goes. Like Sawan, other researchers are going right into the brain so they can use weaker but more efficient electrical signals.

Sawan uses radio waves to connect his external camera with the brain implant, so there is no need for the external connectors that caused problems for Naumann. The technology is still in the trial stage, Sawan says, but the use of these types of implants in humans might be possible in as little as four to five years.

His implant will allow patients to see low-resolution images, he says, but it will be possible to zoom in on objects, so patients should even be able to read: "The patient can be completely independent."

While brain implants best suit people whose eyes are damaged past repair, other researchers are creating implants that go in the eye itself, stimulating the retina to overcome problems including macular degeneration and retinitis pigmentosa.

Optobionics of Glen Ellyn, Ill., has developed a tiny chip that stimulates dormant retinal cells when implanted in the eye. Alan Chow, Optobionics' founder, says his team initially expected electrical impulses from the chip would simply allow patients to see some light, but they actually stimulated dormant cells to start functioning again, restoring near-normal vision.

Trials in about 40 patients showed that while the implant won't restore dead retinal cells, it works in the approximately 60 per cent of cases where cells are simply dormant. But faced with costs of hundreds of millions of dollars for more extensive testing before the device could get regulatory approval in the U.S., Optobionics' backers have pulled out. Chow is trying to revive the company, and says simpler approval procedures in Canada might allow his technology to be used here first.

The Boston Retinal Implant Project has tested a similar implant that bypasses dead photoreceptors in the eyes of patients who suffer from macular degeneration and retinitis pigmentosa. The researchers plan human trials of their latest prototype soon, and Shawn Kelly, a researcher with the project, says the implants would probably cost $40,000 to $60,000 (including surgery) — similar to the cost of a cochlear implant.

Restoring movement

Rajesh Rao is a researcher at the University of Washington.
Vision is just one area of neuroprosthetic development. Researchers are exploring ways to use neuroprosthetics to restore broken communications between the brain and other parts of the body, which could restore natural movement to people who are paralyzed or allow their brains to control prosthetic replacements for missing limbs.

A key to neuroprosthetics is the fact that the human nervous system uses weak electrical impulses to transmit information. The Utah Electrode Array is a tiny device — less than a sixth the size of a penny — that when implanted in the body can "talk" to nerves, telling parts of the body what to do.

Imagine a person paralyzed by spinal cord damage. The muscles function, but the brain can't communicate tell them to move. An electrode array can stimulate those muscles, says Greg Clark, associate professor of bioengineering at the University of Utah, giving the patient some motor control.

There are already simple systems that do this, Clark says, but they lack the fine control to produce smooth and efficient movement, so patients move awkwardly and tire quickly. By transmitting more data, the Utah Array should allow more precise control.

Clark says the ultimate system would use one pair of arrays to relay signals from the brain to nerves in, say, a leg, and two more arrays to return sensory feedback from the leg (so patients would feel their foot touching the floor, for instance). One scientist has already tested an electrode array collecting sensory feedback in his own arm, and all the necessary components have been tested in animals. However, a complete two-way sensory and muscle control system has not yet been built and tested in people, he says.

Other projects focus on using the brain to directly control devices outside the body. The BrainGate Research Team, with researchers at Brown University, Massachusetts General Hospital and Providence VA Medical Center, has tested a brain implant that can use signals from the brain to control a computer cursor.

Reasoning that fine muscle control is a difficult problem, University of Washington researchers are taking a different tack. The Neural Systems Group is experimenting with a small humanoid robot controlled by sensors worn outside the head. Because the robot has intelligence of its own, "when you tell it to pick up an object you don't have to tell it how to move its hand," says Rajesh Rao, associate professor of computer science and engineering. So imprecise signals from many neurons — detectable without an invasive implant — are enough.

Rao says the control system could use a menu where options would flash on a screen one by one, and the sensor would detect the user's recognition of the one wanted. The robot would also learn, so having once been taught step by step how to go to the refrigerator, the next time it would know the way.

Because this system would be worn, not implanted, approvals for its use should be easier, and Rao says possible entertainment uses of the technology could help bring the price down. Like most of today's neuroprosthetic research, it will take time to reach the point where the technology is ready for real-world use.

Still, progress is being made in many areas that help meld  humans and machines. Jens Naumann's brief glimpse of the world a few years ago was a landmark event, and medical technology is going to make that world a lot more accessible to people with a range of physical challenges in the coming years.