sleep stage
Distinct phases of sleep characterized by specific patterns of brain wave activity, eye movements, and muscle tone.
Full Definition
Standardized categories of sleep identified through polysomnographic recordings, including three stages of non-REM sleep (N1, N2, N3) and REM sleep. Each stage has unique electroencephalographic patterns: N1 represents light sleep with theta waves, N2 features sleep spindles and K-complexes, N3 is deep sleep dominated by delta waves, and REM sleep shows rapid eye movements with vivid dreaming. Healthy sleep involves cycling through these stages multiple times per night in a predictable pattern. Sleep stage analysis is fundamental to diagnosing sleep disorders and assessing sleep quality in clinical practice.
Usage
Usage note: Current AASM scoring uses N1, N2, N3 for NREM stages rather than older 1-4 system.
In Context
- "The sleep study revealed abnormal transitions between sleep stages and reduced deep sleep." — Polysomnography interpretation
- "Alcohol consumption before bedtime can disrupt normal sleep stage progression throughout the night." — Patient education material