Eye Pupils Hold Key to Communication: Locked-In Patients Answer Questions

The inability to communicate can drastically affect a person's mental state and well-being. Now, though, researchers have developed a system that allows immobile patients to answer "yes" or "no" questions within seconds by using a laptop and a camera. The new method could be a boon to those who are otherwise unable to interact with others.

The new system revolves around pupil response. It takes advantage of changes in pupil size that naturally occur when people do mental arithmetic.  In order to see if their new system would work, the researchers asked healthy people to solve a math problem only when the correct answer to a "yes" or "no" question was shown to them on a screen. The mental load associated with solving that problem caused an automatic increase in pupil size, which the researchers showed that they could measure and translate into an accurate answer to questions that required "yes" or "no" answers.

"It is remarkable that a physiological system as simple as the pupil has such a rich repertoire of responses that it can be used for a task as complex as communications," said Wolfgang Einhauser, one of the researchers, in a news release.

After testing their system with healthy patients, the researchers then tested it out on seven "typical" locked-in patients who had suffered brain damage following a stroke. It turns out that in many cases, they were able to discern an answer based on pupil size alone.

"We find it remarkable that the system worked almost perfectly in all healthy observers and then could be transferred directly from them to the patients, with no need for training or parameter adjustment," said Einhauser.

That's not to say that the new system is perfect. It could be improved in both terms of speed and accuracy. Yet it does hold potential for the future. Immobile patients could use the new method in order to communicate with others, which could allow them to live more fulfilled lives. It's a big step forward for those who have trouble with communication.

The findings are published in the journal Current Biology.

Want to see the new system in action? You can check it out here.