How is Sleep Latency calculated?

How is Sleep Latency calculated?

• A. (First epoch scored as sleep − lights out) / 2
• B. Lights out epoch minus first epoch scored as sleep
• C. First epoch scored as sleep minus last epoch scored as sleep
• D. (First epoch scored as sleep − lights out epoch) / 2

Answer: (D)

Sleep latency is the time from lights out to the moment you first fall asleep. In PSG scoring, sleep onset is marked by the first 30-second epoch that contains sleep (N1 or higher) after lights out. Since each epoch is 30 seconds, you determine how many 30-second intervals occur between lights out and that first sleep epoch. Dividing that interval count by 2 converts the elapsed 30-second blocks into minutes. So, using the first sleep epoch minus the lights-out epoch, then dividing by 2, gives the sleep latency in minutes.

Sleep latency is the time from lights out to the moment you first fall asleep. In PSG scoring, sleep onset is marked by the first 30-second epoch that contains sleep (N1 or higher) after lights out. Since each epoch is 30 seconds, you determine how many 30-second intervals occur between lights out and that first sleep epoch. Dividing that interval count by 2 converts the elapsed 30-second blocks into minutes. So, using the first sleep epoch minus the lights-out epoch, then dividing by 2, gives the sleep latency in minutes.