K-complex
Pronunciation: KAY-com-plex
Large amplitude biphasic waves occurring in NREM sleep, representing normal sleep architecture and arousal responses.
Full Definition
K-complexes are high-amplitude, biphasic waveforms that occur spontaneously during NREM sleep stages, particularly stage 2. They consist of an initial negative sharp wave followed by a positive slow wave, typically lasting 0.5-2 seconds with amplitude exceeding 75 microvolts. K-complexes represent a normal component of sleep architecture and reflect the brain's ability to maintain sleep while processing external stimuli. They may occur spontaneously or in response to auditory stimuli and are often followed by sleep spindles. The presence and morphology of K-complexes provide important information about sleep quality and neurological integrity.
Usage
Usage note: Hyphenated when used as adjective (K-complex activity) but not as noun (K complex formation).
In Context
- "Well-formed K-complexes were present throughout stage 2 NREM sleep." — Polysomnography report
- "The K-complex morphology appeared normal for the patient's age." — Sleep study interpretation