Sleep can be divided into a number of stages with different characteristics.
Sleep is divided into rapid-eye movement (REM) and non-rapid eye movement (NREM).
NREM is divided into 3 stages: N1, N2 and N3.
|
EEG Feature
|
Clinical Findings
|
Stage
|
|
alpha waves
|
eyes closed
|
wakefulness
|
|
theta waves
|
slow, rolling eye movements
|
N1 (sleep onset)
|
|
sleep spindles and K-complexes
|
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N2 (light sleep)
|
|
delta waves, slow oscillations
|
|
N3 (deep sleep)
|
|
low amplitude, mixed frequencies, saw-tooth theta waves
|
rapid eye movements, muscle atonia
|
REM (paradoxical)
|
|
EEG Wave
|
Hertz
|
|
alpha
|
8-12
|
|
theta
|
4-8
|
|
sleep spindles
|
11-16
|
|
delta
|
0.5-2
|
|
slow oscillations
|
< 1
|
|
Stage
|
Disorders
|
|
N1 (sleep onset)
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hypnic jerks, hypnagogic hallucinations
|
|
N2 (light sleep)
|
bruxism, nocturnal frontal lobe epilepsy
|
|
N3 (deep sleep)
|
somnambulism, sleep terrors, confusional arousals
|
|
REM (paradoxical)
|
REM behavior disorder, nightmares
|
|
|
|
