- Most common sleep stage during a normal night’s sleep.
- Appearance of sleep spindles
- Short burst of waxing and waning rhythmic waves.
- Amplitude of 20-100 microvolt.
- Frequency of 12-16 Hz
- The presence of sleep spindles is necessary and sufficient to define non REM 2 sleep
- First appear in infants of 6-8 weeks old
- Bilateral and synchronous
- Maximum in the frontal and central regions
- Appearance of K complex
- Appearance of <20% Delta waves
- All sleep patterns in Non-REM 1 persist in Non-REM 2, except for slow rolling eye movements (SREM).