Scientists have conducted a trial where they were able to communicate with patients that suffered from advanced forms of amyotrophic lateral sclerosis, a condition where people lose the ability to control their muscles. The trial employed a brain-computer interface that allowed the patients to reply to questions with a simple 'yes' or 'no' response.

The condition still allows patients to think but prevents them from talking or moving, and depending on the severity of the condition, eye movement may also be restricted. The people involved in this study were the worst-affected and could not move their eyes.

The method used in the study is called near-infrared spectroscopy. The activity of brain cells affects the oxygen levels in the blood, which in turn changes the color of the blood. Scientists were able to use light to detect the blood's color using near-infrared spectroscopy and determine the subject's response.

Before the subjects could give reliable answers to the questions being asked, the computer needed to be trained to interpret responses correctly. In order to get reliable answers, the questions had to be asked multiple times to verify the answers given.