Methods and apparatus for controlling air supplied under pressure to a patient suffering from sleep disorders such as apnoea. Controlled pressurized air is supplied to the patient's upper anatomical airways by the apparatus according to the methods of the present invention. The apparatus measures and/or calculates the inspiratory air flow, volume and pressure to the airway. The apparatus further determines whether to increase or decrease the airway pressure based on a determination of several factors, such as the occurrence events representing a sleep problem, duration of inspiratory air flow, correspondence of the inspiratory air flow curve to a sinusoidal curve, air leakage and acoustical vibrations. Occurrences of events representing a sleep problem may be stored by the apparatus and read by a clinician at a later date.