Which EEG pattern defines slow-wave sleep (N3)?

Which EEG pattern defines slow-wave sleep (N3)?

• A. Theta waves
• B. Beta waves
• C. Alpha waves
• D. Delta waves (0.5–4 Hz) with high amplitude

Answer: (D)

The main idea is recognizing which EEG pattern signals the deepest stage of non-REM sleep. Slow-wave sleep, or N3, is defined by delta activity—very slow waves in the range of about 0.5–4 Hz with high amplitude. This large, slow activity reflects highly synchronized neuronal firing and marks the deepest, most restorative part of sleep, when arousal is hardest to achieve. Theta waves occur in lighter sleep (N1) and drowsiness, alpha waves appear during relaxed wakefulness with eyes closed, and beta waves are associated with alert wakefulness. None of these describe the dominant deep, high-amplitude delta activity that characterizes slow-wave sleep.

The main idea is recognizing which EEG pattern signals the deepest stage of non-REM sleep. Slow-wave sleep, or N3, is defined by delta activity—very slow waves in the range of about 0.5–4 Hz with high amplitude. This large, slow activity reflects highly synchronized neuronal firing and marks the deepest, most restorative part of sleep, when arousal is hardest to achieve.

Theta waves occur in lighter sleep (N1) and drowsiness, alpha waves appear during relaxed wakefulness with eyes closed, and beta waves are associated with alert wakefulness. None of these describe the dominant deep, high-amplitude delta activity that characterizes slow-wave sleep.