Obstructed Apnea: Defined as a 90% reduction of airflow lasting at least 10 seconds.
Central Apnea: An absence of respiratory effort for at least 10 seconds, associated with an arousal, or interruption of sleep.
Hypopnea: Defined as a 50% reduction of airflow lasting al least 10 sec.
AHI: Apnoea/hoponea index or AHI represents the number of apnea and hypopnea episodes that occur per hour of sleep.
Oxygen Desaturation Index: The Oxygen Desaturation Index (ODI) is the number of times per hour of sleep that the blood's oxygen level drops by 3 percent or more from baseline. (Normal oxygen saturations - greater than 90-92%)