What are the primary stages of sleep measured in polysomnography?

The primary stages of sleep measured in polysomnography are categorized into Non-REM (NREM) sleep and REM sleep. NREM sleep is further divided into three stages, characterized by varying levels of depth, with stage 1 being light sleep, and stage 3 being deep sleep. REM sleep, on the other hand, is associated with vivid dreaming and increased brain activity. Polysomnography captures these stages by monitoring brain waves, eye movements, muscle activity, and other physiological indicators, allowing for a comprehensive analysis of an individual’s sleep architecture.

This distinction between NREM and REM sleep is crucial for understanding sleep patterns and diagnosing sleep disorders. The presence of both stages is important for overall restorative sleep, making their accurate measurement a key focus of polysomnographic studies. In contrast, the other choices do not effectively encapsulate the established classifications of sleep in polysomnography, as they either oversimplify the concept or use unconventional terminology that does not align with standard sleep science.