A French study showed that it is possible to respond to external requests during sleep

According to research, sleepers without certain disorders are able to pick up verbal information transmitted by the human voice and respond to it through facial muscle contractions. However, these abilities appear intermittently during almost all stages of sleep.

Therefore, there will be intermediate states between wakefulness and sleep. To find out, the researchers analyzed 22 patients without sleep disorders and 27 patients with narcolepsy, who are often able to have lucid dreams (in which they are conscious and can form the scenario).

Nap test

“One of our previous studies showed that two-way communication, from the experiencer to the dreamer and vice versa, is possible during distinct paradoxical sleep,” Delphine Audet, a researcher at the Inserm Institute for Cognitive Neuroscience, explained in a press release. “I wanted to know whether these findings could be generalized to other stages of sleep and to individuals who do not have lucid dreams.”

To do this, participants took a nap during which the researchers spoke a series of real and made-up words, which either had to elicit a frown or a smile, to classify them. Upon waking, patients were asked to report whether they had had a lucid dream and whether they remembered interacting with anyone.

“Most participants, whether narcolepsy or not, were able to respond correctly to verbal stimuli while remaining asleep. These events were certainly more frequent during lucid dreaming episodes, which are characterized by a high level of consciousness; but we observed them occasionally in both groups.” During all stages of sleep,” reveals Isabelle Arnulf, Head of the Department of Sleep Medicine at the Piti-Salpetriere Hospital AP-HP.

Research is still ongoing and it could be used to improve sleep disorders or enhance learning, for example. They can also question the very definition of sleep, the period when the body and mind are at rest, because it may be more active than previously thought.