It's every writer's dream: just look at the page and have the words appear.

Jean Lorenceau, a neuroscientist at the Université Pierre et Marie Curie in Paris, has developed an interface to do that, by tracking eye movement. With a little training, he says, a person can learn to control a cursor on a screen.

This isn't a cure for writer's block, though. Lorenceau sees it as an aid to people who are paralyzed and want to communicate. He plans to test it with people who have Amyotrophic lateral sclerosis, or Lou Gehrig's disease.

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The system works by attaching a camera to the person's head (using a frame for glasses). The camera tracks eye movements. That's more complicated than it sounds, though, because a person's eyes don't move smoothly.


Ordinarily, when a human eye is not following something that moves, it makes what are called saccades. These are tiny, sudden movements. A good way to see this is to watch someone's eyes as they look out the window of a car or subway train. The eyes will smoothly track what's out the window, and snap back. The eyes move smoothly only when they track the moving objects (or, strictly speaking, objects that appear to move across the field of view).

Lorenceau 's system tracks the eyes for 30 seconds at a time. The movement data is sent to a computer that can then ignore the saccades. If the user moves the eyes as though they were writing something, the eye behaves as though it were tracking a real object even if one isn't there. It does take some practice though, because the person is learning to "see" his or her own eye movements, which are largely involuntary.

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The system isn't as sophisticated as it could be — there are ways to add processing to smooth out the movement more. But for poeple who cannot write with their hands, this technology could allow them to communicate more fully.

Image: Lorenceau et al., Current Biology