Sleep Apnea Overview


Different forms of sleep apnea

Sleep apnea is a sleep disorder characterized by abnormal pauses in breathing or instances of abnormally low breathing during sleep. There are three types of sleep apnea:

  • Obstructive sleep apnea
  • Central sleep apnea
  • Complex sleep apnea

Of the three, obstructive sleep apnea (OSA) is by far the most common. It is caused by an absence of air flow due to an occlusion in the upper airway that lasts for at least 10 seconds, in spite of a continual effort to breathe. (More simply put your airway collapses and you can’t breathe). It is characterized by repetitive pauses in breathing during sleep and is usually associated with a reduction in blood-oxygen saturation. The breathing pauses that are called “apneas” (Latin for, “without breath”) typically last 20 to 40 seconds and may occur 5 to 30 or more times per hour. Severity of the condition is measured by the number of times these pauses in breathing occur per hour of sleep (the Apnea-Hypopnea Index or AHI). OSA is one of the causes of chronic loud snoring.

Central sleep apnea (CSA) is a form of sleep disordered breathing characterized by a normal deep inspiratory cycle interchanged with complete cessation in breathing. CSA is caused by the temporary absence of a signal from the brain’s repository center. Without this signal there is no effort to breath.

Complex sleep apnea is a form of sleep apnea that is triggered by attempt to treat OSA using positive airway pressure (PAP) therapy. It is sometimes called mixed sleep apnea as it is characterized by both OSA and CSA events that convert to all or predominately CSA events with PAP therapy. The cause is not known.