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, described and demonstrated in Current Biology, a Cell Press publication, on August 5 takes advantage of changes in pupil size that naturally occur when people do mental arithmetic. It requires no specialized equipment or training at all. 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 say. To see more details visit, www.medicalnewstoday.com