Non-rapid eye movement sleep

Non -REM sleep (also: Orthodox sleep or NREM sleep) is in sleep research and sleep medicine in addition to REM sleep ( REM, Rapid Eye Movement engl. ) One of the two forms of sleep.

Classification and features

In the further classification of NREM sleep is divided into the sleep stages N1, N2 and N3. This nomenclature is due to a publication of the American Academy of Sleep Medicine in 2007. The sleep stage N1 represents the transition between waking and sleeping, N2 and N3 is stable sleep deep sleep. The NREM sleep as a whole is also called a sleep stage N.

The individual sleep stages have characteristic features in the electrical activity of the brain and are determined by measurement and separable. The allocation of time segments of sleep to the sleep stages occurs in the evaluation of the conducted by polysomnography study and is used to assess sleep in the diagnosis of sleep disorders. The display is in sleep profile ( hypnogram ). In this context, the term R is used for the stage REM and stage W to the awake state.

The body temperature and blood pressure of the sleeper fall from the NREM sleep and he dreams hardly.

The proportion of each sleep stage on the duration of sleep is not a fixed quantity, but varies depending on the gender with age. Per night it comes in healthy humans to 4-7 sleep cycles of about 70-110 minutes, in which the NREM stages N1, N2 and N3 and N2 again followed by REM sleep are run. In the following cycles of deep sleep decreases and the proportion of REM to share. In an about 30 -year-old people, the percentage of NREM stages 3 lies on the entire duration of the night's sleep above 70%.

Sleep stage N1

Transition between wakefulness and sleep:

  • The electroencephalogram (EEG ) shows theta activity, in healthy adults, a sign of sleepiness.
  • The electromyogram ( EMG) shows a decrease in muscle tone compared to the waking state.
  • The electrooculogram (EOG ) shows slow, partly rolling eye movements.

The proportion of the total duration is in middle age (about 30 years) at about 5%.

Sleep stage N2

Stable sleep:

  • The EEG shows theta activity, K - complexes and sleep spindles.
  • The EMG shows a decrease of muscle tone over the stage N1.
  • The EOG shows no eye movements.

The proportion of the total duration is in middle age (about 30 years) at about 45-55 %.

Sleep stage N3

Deep sleep:

  • The EEG shows delta activity.
  • The EMG shows a decrease of muscle tone over the stage N2.
  • The EOG shows no eye movements.

The proportion of the total duration is in middle age (about 30 years) at about 15-25%.

Sleep stages according to Rechtschaffen and Kales

An earlier and used for many years nomenclature goes back to a publication by Allan Rechtschaffen and Anthony Kales in 1968. There, the NREM sleep was divided into 4 stages, 2 light sleep stages and 2 deep sleep stages. The words' to R K "in the relevant literature refers to this classification. The two deep sleep stages are now combined as stage N3.

Somnology Electromyography
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