Music like Dream State

Hypnagogia, also referred to as "hypnagogic hallucinations", is the experience of the transitional state from wakefulness to sleep: the hypnagogic state of consciousness, during the onset of sleep. (The opposite transitional state from sleep into wakefulness is described as hypnopompic.) Mental phenomena that may occur during this "threshold consciousness" phase include hallucinations, lucid thought, lucid dreaming, and sleep paralysis. The latter two phenomena are themselves separate sleep conditions that are sometimes experienced during the hypnagogic state.

The word hypnagogia is sometimes used in a restricted sense to refer to the onset of sleep, and contrasted with hypnopompia, Frederic Myers's term for waking up. However, hypnagogia is also regularly employed in a more general sense that covers both falling asleep and waking up. Indeed, it is not always possible in practice to assign a particular episode of any given phenomenon to one or the other, given that the same kinds of experience occur in both, and that people may drift in and out of sleep. In this article hypnagogia will be used in the broader sense, unless otherwise stated or implied.