US festival of science:Modern electronics has helped blind people to regain limited sight and has enabled people who are paralysed to grasp objects and stand. The next generation of devices will also allow movement to be controlled by thought alone, writes Dick Ahlstrom, Science Editor, in San Francisco
The integration of electronics and the body's nervous system provided an intriguing session yesterday at the American Association for the Advancement of Science's annual festival of science in San Francisco.
Participants heard that the US Food and Drug Administration (FDA) had just granted permission for a human trial of a device called the Argus II retinal prosthesis system. Implanted in the eye, it restores rudimentary sight to blind people with certain conditions.
The developer, Mark Humayun, professor of ophthalmology at the Doheny Eye Institute at the University of Southern California, implanted an earlier device in six patients. He now hopes to recruit up to 75 patients suffering with blinding conditions such as macular degeneration and retinitis pigmentosa to test the new, more advanced device at five centres in the US.
The original device involved implanting 16 tiny electrodes in the retina. The subject then wore a pair of seemingly ordinary glasses, which were in fact fitted with a small camera, Prof Humayun explained: "We were very sensitive to [ how they looked], so the glasses didn't look like a science experiment."
Images from the camera are processed and sent as a wireless signal via the frames into the implant in the eye. The subject sees a four-by-four matrix of dots of light and this gives them a crude visual image.
Subjects were able to differentiate between simple objects such as a cup, a knife and a plate, but Prof Humayun believes that the new device, which has 60 electrodes, will deliver much better vision.
The device is being developed in conjunction with a company called Second Sight Medical Products, which will manufacture the implant.
Prof Humayun expects that fitting the implant would cost in the region of €24,000.
Asked when the implant might be available, he responded: "Depending on the results of the trial, it could be as soon as two years."
Implants of a different kind were described by Prof Hunter Peckham, of Case Western Reserve University. His Functional Electrical Stimulation Centre in Virginia develops implanted muscle stimulation devices which enable subjects who are paralysed as a result of disease or injury to regain control over their limbs.
The centre develops electronic control devices which activate implanted units. These send a small current through a muscle, causing it to contract.
One of Prof Peckham's subjects, Jennifer French, who suffered spinal-cord damage, attended the session. With the help of the device, she stood up from her wheelchair to address the meeting.
The devices can be used for a range of conditions and to control various muscle groups, including arm movement, leg movement and gripping with the hand, Prof Peckham said.
Prof John Donoghue, a neuroscientist from Brown University in Rhode Island, wants to take this approach a step further, using nothing more than thought to control electronic devices. His research group is developing BrainGate, a brain-computer interface.
An implant is positioned on the brain's surface and external pick-ups link this to a computer. In this way the muscle stimulator devices being developed by groups such as Prof Peckham's can be switched on and off by thought alone.
BrainGate has already been used to enable people with paralysis to direct a computer cursor, control a wheelchair and operate a robotic hand in FDA-approved clinical trials.
Prof Donoghue oversees the trials conducted by Cyberkinetics Neurotechnology Systems, the Massachusetts company which is developing and testing the technology.