During which sleep stage are K complexes typically observed?

K complexes are typically observed during Stage N2 sleep. This sleep stage is characterized by specific brain wave patterns and is considered a transitional phase between light sleep and deeper sleep. K complexes appear as sharp, high-voltage waves that can last a fraction of a second to a few seconds and are thought to be a response to external stimuli or disturbances in the environment. Their presence is considered a marker of Stage N2 sleep, contributing to the overall architecture of sleep cycles.

In addition, Stage N2 represents a significant portion of total sleep time in adults, encompassing roughly 45-55% of total sleep. This stage plays an essential role in sleep maintenance and memory consolidation, with K complexes aiding in the protection of sleep by suppressing brain activity in response to environmental stimuli. Understanding the characteristics of each sleep stage, including the occurrence of events like K complexes, is crucial for polysomnographic technologists in accurately interpreting sleep studies.