Some of the most common signs and symptoms of OSA include:
While in the depth of sleep, airway obstruction occurs due to poor muscular tone. In response to an obstructive event, the brain partly awakens which is called an arousal. During an arousal, muscular tone is increased and the obstruction to breathing is relieved. Multiple arousals from deep sleep occur all night long in response to the repetitive apneic and hypopneic events. Perhaps this is a natural defense mechanism which prevents suffocation, but at the expense of high quality sleep. Repetitive nocturnal obstruction to breathing results in poor quality sleep with visible symptoms of sleep deprivation.
Many factors may lead to OSA. The characteristics of the skeletal and soft tissues supporting the throat are important. Some include:
Male gender, excess weight or obesity, and aging are also typical risk factors for OSA. Additionally, the use of alcohol, sedatives, tranquilizers or antihistamines around bedtime can lead to snoring and OSA.
The diagnosis of OSA is made by a test commonly called a sleep study or polysomnogram. This is performed in a facility accredited by the American Sleep Disorders Association (www.sleepassociation.org) and requires an overnight stay. The study measures multiple body functions, including efforts at breathing, oxygen levels, heart rhythms and EEG while you sleep.
The repetitive night-time blockage to breathing interferes with the normal physiology of sleep. Normal sleep architecture is seen as characteristic electroencephalogram (EEG) waveforms and durations at the different levels of sleep. With OSA the normal EEG architecture is altered such that the deepest and most restful levels of sleep are minimized or abolished.