Aug. 6, 2012 at 9:05 AM ET
People suffering from motor neuron diseases, such as ALS, often lose their ability to speak. Being unable to communicate can be frustrating and alienating. To help them, various researchers have searched for ways to help such patients “talk.”
A researcher in France taught people to write with their eyes, making it possible for people who lost the ability to speak to communicate again.
Jean Lorenceau, director of research in cognitive neuroscience at CNRS (the French National Centre for Scientific Research), and six others learned how to use smooth pursuit eye movements to write in cursive. Smooth pursuit eye movements are those we use to track something as it moves, like watching a car drive down the street. These movements only occur if there is something for the eye to follow.
“We have an exquisite, fast, and accurate oculomotor system that has a whole repertoire of movements,” says Lorenceau via email.
“Too bad that [the oculomotor system] is only used to see and cannot be used to act on the environment. Cursive writing is continuous, curved, and smooth, just as pursuit eye movements are, so [these] eye movements should be suitable for this activity.”
In anywhere from three to five, 30-minute training sessions (the faster the learner, the fewer training session), the subjects learned how to control their smooth eye muscle movements to write in cursive.
“We move the eyes all the time, so eye writing relies on a natural activity, although slightly unusual,” he says.
On a computer screen, Lorenceau projected a reverse phi-movement effect, an optical illusion where static objects look like they are moving, in the background as the object that the eye tracks. This allowed them to learn how to independently move their eyes using smooth pursuit eye movements.
"[The paper] presents a novel and highly innovative new technique for gaze-controlled cursive writing," explains Miriam Spering, an assistant professor in the department of ophthalmology and visual sciences perception and action at the University of British Columbia."The type of eye movement used here are so-called smooth pursuit eye movements--the eyes' main response to moving visual stimuli. Until [Lorenceau's] contribution, it was widely believed that this type of eye movement could not be controlled at will."
Lorenceau recorded the subjects, using an eye tracker, a video camera connected to a computer. As the camera films the movement in one eye, a software program tracks the position of the pupil over time and Lorenceau collects all the recorded movements and compiles them, making the letters.
While learning how to move their eyes—which Lorenceau says is similar to learning how to surf and stay on a wave—the subjects experienced frustration because they could not initially force their eyes to move how they wanted. Users cannot see what they are writing with their eyes; it can be tiring and confusing at times.
While others have designed systems that enable people to communicate with their eyes by blinking to select a letters from a screen or to surf the web, Lorenceau’s method offers something more.
“My device brings personal, creative, and emotional ways of communication, for instance the ability to sign a document using one’s signature,” he explains.
Lorenceau plans on testing this technology with people with ALS. And he is working with a French technology company to create other applications of this system so that it might be easier for people to access.
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