Obstructive sleep apnea (OSA) is one of the most common sleep disorders. It is characterized by repetitive obstruction of the upper airways during sleep. The frequency of such events can range up to hundreds of events per sleep-hour. Full closure of the airways is termed apnea, and a partial closure is known as hypopnea. The number of apnea/hypopnea events per hour is known as the AHI-index, and is used by clinical community as a measure of the severity of OSA. OSA, when untreated, presents as a major public health concern throughout the world. OSA patients use health facilities at twice the average rate (Delaive, Roos, Manfreda, & Kryger, 1998), causing huge pressures on national healthcare systems. OSA is associated with serious complications such as cardiovascular disease, stroke, (Barber & Quan, 2002; Kryger, 2000,), and sexual impotence. It also causes cognitive deficiencies, low IQ in children, fatigue, and accidents. Australian Sleep Association reported (ASA, 1999) that in the state of New South Wales alone 11,000–43,000 traffic accidents per year were attributable to untreated-OSA.
Key Terms in this Chapter
EEG Arousals: An abrupt shift in EEG frequencies during sleep which may include a, ?, and/or frequencies <16Hz, excluding structures known as sleep spindles.
Respiratory Disturbance Index (RDI): The number of all respiratory disturbances per hour, averaged over the entire duration of sleep.
Oxygen Desaturation: A decrease in the blood oxygen levels often associated with sleep apneas.
International 10/20 Electrode System: A standard placement of electroencephalographic (EEG) electrodes on the scalp to measure signals from the brain.