delta wave
Pronunciation: DEL-ta wave
Slow brain waves (0.5-2 Hz) characteristic of deep NREM sleep stages.
Full Definition
Delta waves represent the slowest brain wave frequency recorded during sleep, ranging from 0.5 to 2 Hz with high amplitude typically exceeding 75 microvolts. These waves are the defining characteristic of stage N3 sleep (slow-wave sleep or deep sleep) and are generated by synchronized firing of cortical neurons. Delta wave activity is highest during the first third of the night and decreases with age. The presence and distribution of delta waves are crucial for sleep stage scoring and assessing sleep quality, as reduced delta activity is associated with various sleep disorders and cognitive impairment.
Usage
Usage note: Specify frequency range when technical precision is required; distinguish from general 'slow-wave sleep' terminology.
In Context
- "The EEG showed abundant delta wave activity during the first sleep cycle." — Polysomnography interpretation
- "Age-related reduction in delta waves contributes to lighter, more fragmented sleep in older adults." — Research literature