A new study in the Sept. 1 issue of the journal Sleep investigated lucid dreaming.
What is lucid dreaming? It involves the conscious awareness of dreaming while you are still asleep.
Lucid dreaming combines aspects of waking and dreaming. You have hallucinatory dream activity along with reflective awareness; you realize that you are not awake and are dreaming. In contrast, during non-lucid dreams, you mistakenly think that you are awake. Lucid dreaming also can involve the ability to control what happens during the dream.
Lucid dreams tend to occur after several hours of sleep; they are more common during later periods of rapid eye movement sleep – or REM sleep. The longest period of REM sleep may last for an hour near the end of the night. REM sleep makes up about 25 percent of total sleep time in normal adult sleep.
According to the authors, spontaneous lucidity is rare. But people can be trained to become lucid. A special electronic device can help induce lucidity; these devices emit specific light or sound signals.
But most often the training is done through pre-sleep “autosuggestion.” Before going to sleep, you tell yourself to recognize when you are dreaming; you prepare yourself to notice the bizarre events of the dream.
The authors also report that it is possible for you to communicate that you have become lucid during sleep; you can make a sequence of voluntary eye movements as a signal.
The study preparation involved 20 college students in Bonn, Germany. They took part in weekly lucidity training sessions. After four months, six people claimed to be lucid more than three times per week.
These six volunteers participated in the study. Their sleep was monitored during multiple overnight sleep studies.
Results show that three of the six volunteers were able to have a lucid dream in the sleep lab. In each case, lucidity occurred in the morning hours.
The dreamers were able to signal that they had become lucid with a pattern of horizontal eye movements. Lucidity also was confirmed by self-report after waking.
Brain-wave recordings confirmed that lucid dreaming occurs during sleep. But the recordings also showed that it differs from REM sleep.
The authors suggest that lucid dreaming is a “unique, hybrid state of sleep”; it involves features of both REM sleep and wakefulness. They conclude that lucidity requires a shift in brain activity during sleep.
This post was first published on the Sleep Education Blog on Sept. 15, 2009.