Polysomnography PSG a.k.a. sleep study:
What is recorded:
- Eye movements: REM vs Non-REM
- EMG (submental or limb): tone
- Electroencephalography (EEG): alpha and theta activity
- O2 saturation
Normal REM sleep:
- REM Rapid eye movements
- EMG: minimal to no EMG tone
- EEG: mixed alpha and theta activity
- Hypopnea: 10 seconds of decrease in airflow for <10 secons by >50%. Or decrease in airflow <50% with arousal. Or decrease in airflow <50% with 3% desaturation.
- Apnea: decrease in airflow =or>80% for 10 seconds.
- Obstructive apnea: apnea that occurs with continued respiratory effort.
- Central apnea: apnea without continued respiratory effort
- Hypoventilation: increased CO2