Sleep Stages and EEG : Mnemonic

Mnemonic: BATS Drink Blood – in sleep

1. Awake with eyes open: Beta wave (highest frequency and lowest amplitude)

2. Awake with eyes closed: Alpha wave (synchronized brain activity)

3. NREM/Slow wave/Orthodox sleep (70-80%):

• Stage 1 (light sleep): Theta waves
• Stage 2 (intermediate): Sleep spindles and K-complex
• Stage 3 and 4 (deep sleep): Delta waves (lowest frequency and highest amplitude)

4. REM/Paradoxical sleep (20-30%): Beta waves

Order in which frequency decreases and amplitude increases: BAT Drink

1. Beta wave: >14 Hz, low amplitude
2. Alpha wave: 8-13 Hz, high amplitude
3. Theta wave: 4-7 Hz, high amplitude
4. Delta wave: 3-5 Hz, maximum amplitude