Washington: Patients with altered state of consciousness may now be able to communicate with a system that measures the size of their pupils, a new study has found.
Patients who are otherwise completely unable to communicate can answer yes or no questions within seconds with the help of a simple system-consisting of just a laptop and camera- that measures nothing but the size of their pupils.
The tool, developed by Philipps-Universityt Marburg in Germany, takes advantage of changes in pupil size that naturally occur when people do mental arithmetic and it requires no specialized equipment or training at all.
According to researchers, the new pupil response system might not only help those who are severely motor-impaired communicate, but might also be extended to assessing the mental state of patients whose state of consciousness is unclear.
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 they could measure and translate into an accurate answer to questions like "Are you 20 years old?"
They then tested out their pupil response algorithm on seven "typical" locked-in patients who had suffered brain damage following a stroke. In many cases, they were able to discern an answer based on pupil size alone.
The study is published in journal Current Biology.