According to they have demonstrated electroencefalográficos studies to it, the dream consists of two precise states: dream MOR (fast ocular movements), also called of dream, paradoxical state D or, and dream NMOR (noncMor). By different electroencefalográficos patterns, the dreams happen mainly in state MOR and smaller degree in the NMOR. The dream is a cyclical phenomenon, with four or five periods MOR during the night that correspond to almost one fourth part of the total of the nocturnal dream (one and average one to two hours).

First period MOR appears 80 to 120 minutes after beginning to sleep and lasts around 10 minutes. Later periods MOR more are prolonged (15 to 40 minutes) and happen mainly in the last hours of the dream. Almost all stage four (deepest) happens in the first hours. The alterations of the normal dream related to the age include a constant increase of dream MOR and diminution of stages three and four, with more periods in than awakes during the night.

These normal changes and the siestas in the day have a paper in the increase of the insomnia in age people outpost. The variations in the patterns of the dream can depend on the circumstances (for example, "delay of the jet") or on idiosincráticos patterns ("trasnochadores") in people in which perhaps by different biological rates they lie down late and usually they sleep until late in the morning. It also has individual rare with chronic difficulties to adapt to a cycle to sleep and to wake up of 24 hours (upheaval by desincronización of the dream).

Insomnia, is the traditional term, although disomnio would be the most precise term.

The fleeting episodes are common and they do not have importance. The persistent insomnia (by more than three weeks) is commonest in age people outpost for the commented reasons.

It is possible that the clients complain

1) difficulty to sleep or to remain slept
2) to wake up intermittent during the night
3) to early wake up in the morning
4) combinations of anyone of them.