“Gentlemen, we can rebuild him. We have the technology. We have the capability to make the world’s first bionic man.”
So began each episode of The Six Million Dollar Man, of which I was a big fan not all that many decades ago.
At the time, of course, the idea of “rebuilding” a man with artificial parts was pure science fiction. But science fiction is, after all, the extrapolation of present-day trends into the future, and the future is here.
Consider the artificial heart that surgeons in Louisville, Kentucky recently implanted in an unnamed patient. The AbioCor is a battery-powered pump. Unlike the first artificial heart, the air-driven Jarvik 7, implanted in 1982, which required all kinds of tubes leading from the patient to a console, the AbioCor is entirely self-contained, recharged by a battery pack worn by the recipient, which transfers energy through the skin to an internal coil.
As I write this, the recipient is improving and the AbioCor is functioning flawlessly. (In animal tests, it kept calves alive and healthy for three months, after which they were slaughtered only because they had outgrown the device.) Although doctors fully expect all of the initial recipients of the experimental heart will die, all only had a month or so to live anyway before their hearts gave out. This work, researchers hope, will lead to even better artificial hearts in the future.
Meanwhile, a bionic ear holds promise for people who have gone deaf. More than 500 deaf Americans already wear one part of the year, surgical implants below the skin in the back of the head that convert sounds into electrical impulses and send them to the main hearing nerve. But what they hear sounds very synthetic. Ten Americans are wearing the new ear, which features software 10 times more sensitive and produces sounds that are much more natural. Doctors expect the FDA to approve the new $50,000 device by the end of the year.
And then there’s the bionic eye. A year ago, doctors in Illinois implanted the first permanent artificial silicon retinas (ASRs) in the eyes of three patients suffering from the hereditary disease retinitis pigmentosa, which causes blindness by damaging the eyes’ light-sensitive cells. Invented by opthamalogist Alan Chow and his brother Vincent Chow, an electrical engineer, the ASR is a silicon chip two millimetres in diameter and 1/2500th of a millimetre thick. It contains 3,500 microscopic photosensors, which turn light into electrical energy and stimulate the remaining functional cells in the patients’ eyes. The Chows are hopeful that in a few years they may have a device that provides at least some level of sight to victims of retinitis pigmentosa and macular degeneration.
Scientists at several U.S. universities are working on a more complex bionic eye that uses captures images with a small, eyeglass-mounted video camera. The digitized images are then beamed via a laser beam into a solar-powered microchip implanted in the eye (the laser also powers the chip). Photosensors on the chip convert the light and images into electrical impulses, which stimulates the nerves that transmit visual information to the brain. Human trials are expected to begin in early 2002.
Artificial limbs, too, are improving all the time. The current state-of-the-art prosthetics are myoelectrically controlled–electrodes inside the socket of the limb pick up movements of muscles in the stump, and transform them into the appropriate movements. The most common use is to control an artificial hand, telling it to open or close.
Many scientists doubt we’ll ever create bionic hands that are indistinguishable from the real thing. But…
Biomedical engineers in Virginia have developed a prototype system that combines muscle-stimulating electrodes implanted under the skin with a computer sensitive to brainwaves, allowing a quadriplegic to grasp and manipulate objects with his paralyzed hand just by thinking about it. The test subject trained with a computer to learn to move a cursor up or down just by thinking about it, then translated that ability to his own limbs. He can open and close his hand and pick up objects like a drinking glass and a fork, but he has to keep thinking “open, open, open” all the time or he loses control. (To make things easier, a switch has been added that locks his hand open until he thinks “close,” and vice versa.)
Although the system is designed for quadriplegics, it’s not hard to imagine it being used to manipulate prosthetic limbs.
Maybe we can’t build The Six Million Dollar Man yet…but we’re getting close!
