Delta waves must be how many microvolts (µV) in amplitude to count toward stage N3 sleep percentages?

Delta waves must be how many microvolts (µV) in amplitude to count toward stage N3 sleep percentages?

• A. 75µV
• B. 30µV
• C. 100µV
• D. 55µV

Answer: (A)

Delta activity used to define deep sleep must reach a high amplitude, specifically at least 75 microvolts, and occur in the slow-frequency range about 0.5–2 Hz. When such delta waves are present for a substantial portion of the 30-second epoch (typically at least 20%), the epoch can be scored as stage N3. The 75 µV threshold is the key criterion that distinguishes true slow-wave activity from lighter sleep stages, which have smaller, less intense waves. Other amplitudes do not meet this standard, so they would not contribute to counting N3 sleep.

Delta activity used to define deep sleep must reach a high amplitude, specifically at least 75 microvolts, and occur in the slow-frequency range about 0.5–2 Hz. When such delta waves are present for a substantial portion of the 30-second epoch (typically at least 20%), the epoch can be scored as stage N3. The 75 µV threshold is the key criterion that distinguishes true slow-wave activity from lighter sleep stages, which have smaller, less intense waves. Other amplitudes do not meet this standard, so they would not contribute to counting N3 sleep.