Periodic ventilation, often called CHEYNE Stokes ventilation, results from a dysfunction of the mechanisms of the control of breathing. In this type of ventilation, alternating periods of hyperventilation and apneas and/or hypoventilation replace the normal regular pattern of breathing. Periodic ventilation occurs preferentially during sleep. It is responsible for decreases in arterial saturation in oxygen and for sleep fragmentation. There is currently no consensual treatment but non-invasive nocturnal mechanical ventilation is often used to bring the ventilatory pattern back to normal.