Which statement best describes why sleep stage percentages are calculated in PSG reports?

Which statement best describes why sleep stage percentages are calculated in PSG reports?

• A. To quantify the distribution of sleep stages over total sleep time
• B. To identify electrode placement errors
• C. To measure respiratory rate
• D. To calculate total recording time

Answer: (A)

Sleep stage percentages quantify how the night’s sleep is distributed across stages by expressing each stage as a share of the total sleep time. In PSG, sleep is scored in 30-second epochs as N1, N2, N3, or REM. The time spent in each stage is summed and divided by the total sleep time to produce a percentage for that stage. This normalization lets you compare sleep architecture across nights or individuals and understand the balance of light sleep, deep sleep, and REM. It’s not about electrode placement errors, respiratory rate, or simply the length of the recording. Those are assessed separately, while stage percentages focus on how sleep is distributed over time.

Sleep stage percentages quantify how the night’s sleep is distributed across stages by expressing each stage as a share of the total sleep time. In PSG, sleep is scored in 30-second epochs as N1, N2, N3, or REM. The time spent in each stage is summed and divided by the total sleep time to produce a percentage for that stage. This normalization lets you compare sleep architecture across nights or individuals and understand the balance of light sleep, deep sleep, and REM. It’s not about electrode placement errors, respiratory rate, or simply the length of the recording. Those are assessed separately, while stage percentages focus on how sleep is distributed over time.