The largest, slowest waves seen on EEG are characteristic of which sleep depth?

The largest, slowest waves seen on EEG are characteristic of which sleep depth?

• A. Delta waves
• B. Theta waves
• C. Sleep spindles
• D. Hypnic jerk

Answer: (A)

Deep sleep shows the largest, slowest EEG waves. These are delta waves—high in amplitude and very low in frequency (about 0.5–4 Hz). This pattern marks slow-wave sleep, the deepest non-REM stage (often called slow-wave sleep or stage N3). Theta waves (4–8 Hz) appear in lighter sleep and drowsiness, sleep spindles (brief bursts of 12–14 Hz) occur in stage N2, and a hypnic jerk is a sudden muscle movement at sleep onset, not an EEG sleep-depth feature. So the presence of large, slow delta waves points to deep, restorative sleep.

Deep sleep shows the largest, slowest EEG waves. These are delta waves—high in amplitude and very low in frequency (about 0.5–4 Hz). This pattern marks slow-wave sleep, the deepest non-REM stage (often called slow-wave sleep or stage N3).

Theta waves (4–8 Hz) appear in lighter sleep and drowsiness, sleep spindles (brief bursts of 12–14 Hz) occur in stage N2, and a hypnic jerk is a sudden muscle movement at sleep onset, not an EEG sleep-depth feature. So the presence of large, slow delta waves points to deep, restorative sleep.