Thursday, March 25, 2010

Back to School: Dental Sleep Medicine Terms Explained – Part I

Confused about the commonly used acronyms of sleep medicine? Take out a pen or pencil and get ready to learn.

Obstructive sleep apnea (OSA) - A sleep-related breathing disorder (SBD) that occurs when the tissues in the throat collapse during sleep, causing a partial or complete halt in airflow.

Most pauses last between 10 and 30 seconds, but can persist for one minute or longer. They can happen hundreds of times a night.

The collapses lead to low blood-oxygen levels. When the oxygen drops too low, the brain arouses the body to breathe. This pattern can lead to excessive daytime sleepiness and other health problems.

Most people with OSA snore loudly and frequently, with periods of silence when airflow is blocked. They may make choking, snorting or gasping sounds when their airway reopens.

Polysomnogram (PSG) – Also known as a sleep test, a PSG helps determine the presence of OSA. A sleep specialist will conduct a PSG at a sleep center.

This blog post describes the sleep center experience in detail. Many sleep centers have a hotel-like feel to help visitors fall asleep easily despite being away from home.

In part, sleep specialists diagnose OSA based on the results described below.

Apnea-Hypopnea Index (AHI) – The average number of apneas (full breaks) and hypopneas (partial breaks) that occur per hour of sleep as measured by a PSG.

Mild OSA: AHI of 5-15
Involuntary sleepiness during activities that require little attention, such as watching TV or reading
Moderate OSA: AHI of 15-30
Involuntary sleepiness during activities that require some attention, such as meetings or presentations
Severe OSA: AHI of more than 30
Involuntary sleepiness during activities that require more active attention, such as talking or driving

Respiratory Disturbance Index (RDI) – Like the AHI, RDI counts the number of apneas and hypopneas in breathing per hour of sleep. It may also include respiratory events that disturb sleep but do not qualify as an apnea or hypopnea. The RDI may be higher than the AHI because of the extra events.

Oral Appliance Therapy (OAT) – Describes the treatment that qualified dentists can perform for patients who have been diagnosed with OSA at a sleep center. Oral appliances look like mouth guards, but are worn during sleep. These devices are portable, silent and non-invasive. They move the lower jaw forward to keep a patient’s airway open during sleep. Learn more about OAT here.

Source: American Academy of Sleep Medicine Fact Sheet

Image by Greenhem

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The Official Blog of the American Academy of Dental Sleep Medicine (AADSM) is intended as an information source only. Content of this blog should not be used for self-diagnosis or treatment, and it is not a substitute for medical care, which should be provided by the appropriate health care professional. If you suspect you have a sleep-related breathing disorder, such as obstructive sleep apnea (OSA), you should consult your personal physician or visit an AASM-accredited sleep disorders center. The AADSM, and the American Academy of Sleep Medicine, as the managing agent of the AADSM, assume no liability for the information contained on the Official Blog of the AADSM or for its use.