Some individuals in vegetative and minimally conscious states can learn and thereby demonstrate at least partial consciousness, scientists in Argentina and the UK report.

By using classical Pavlonian conditioning, the researchers played a tone immediately prior to blowing air into a patient’s eye. After some time training, the patients would start to blink when the tone played but before the air puff to the eye. This type of learning was not seen in the control group of subjects, who had been under anaesthesia.

The researchers suggest that this could be a useful, simple tool to test for consciousness, and the fact that these patients can learn associations shows that they can form memories and may benefit from rehabilitation.