Tracing curves with the eye

For more than 25 years, the voice of British physicist Stephen Hawking has been generated with the help of computers, special software that converts text to speech and his twitching cheek muscle. Concerns were raised several months ago that Hawking’s cheek muscle is weakening, making it difficult for him to communicate with others.

One of the alternative methods of communication reportedly being considered for him involves using brain scans to first monitor and then somehow transfer and translate the information straight from the scientist’s mind. Another kind of technology relies on eye-tracking software that can do a variety of things such as turning spelled-out words into speech and remotely controlling devices.

Cursive eye writing

A French researcher recently proposed another type of eye-tracking software that could one day prove beneficial to Hawking and others unable to use their limbs or voices to communicate. In a report published online July 26 in the journal Current Biology, Jean Lorenceau of Universite Pierre et Marie Curie-Paris detailed a method by which eye movements could be tracking on a flickering display. With training, he noted, users could scribble up to 30 characters a minute using their eyes, a rate comparable to that of someone writing a note by hand.

“Using cursive eye writing,” Lorenceau concluded in his report, “people deprive of limb movement could enjoy a personal and emotionally rich way of communicating with others, drawing figures or their own signature at will, offering a large palette of possibilities not available with current eye-writing devices.”

With half a dozen volunteers, Lorenceau himself underwent training to write with their eyes. He noted that current eye-tracking technology relies on someone quickly focusing on a target in the display such as a particular letter or an icon. If such eye movements or saccades were represented by a laser pointer being aimed at a screen, the laser dot would erratically jump all over the display. When writing by eye, however, people need to focus on making smooth eye movements. For example, writing the letter “m” requires lines that move both forward and backward, as well as curve.

Comfortable enough

After a handful of short sessions, the study participants became comfortable enough with the required eye movements to write out words such as “eye” or numbers. “Contrary to the current belief, we show that one can gain complete, voluntary control over smooth pursuit eye movements,” Lorenceau said in a statement. “The discovery also provides a tool to use smooth pursuit eye movements as a pencil to draw, write, or generate a signature.”

The French team is working on improving their eye writer and hopes to start tests with patients who, like Stephen Hawking, have amyotrophic lateral sclerosis. It’s not clear yet when the technology will be available for people who can’t move their limbs to share their thoughts through virtual displays of penmanship that could become as personally distinctive as the 70-year-old Hawking’s computer-generated voice.

E-mail the author at massie@ massie.com.