Sleep Medicine Acronyms (From APAP to Zzzz): Part 4, S-Z

It can be frustrating trying to understand medical jargon of any kind. Sleep medicine acronyms are no exception.

Here is a series on abbreviations you are likely to encounter during your visits to a sleep specialist or sleep center. 

This fourth section highlights terms that start with the letters S through Z. 

See also: 

Sleep Medicine Acronyms (S-Z) 

 

S

SBD/SRBD/SDB

Sleep Breathing Disorder/Sleep Related Breathing Disorder/Sleep Disordered Breathing. This term references sleep disorders which impair respiratory system processes during sleep. They include snoring, upper airway resistance, sleep apnea, and hypoventilation. Learn more: 

 

SL

Sleep Latency. This measures the length of time that it takes to fall sleep, usually in stage 1 nonREM sleep, though sleep may also be initiated in other sleep stages. It is SL that is critically examined during the sleep test known as the MSLT. Learn more: 

 

SO

Sleep Onset. This is the moment you fall asleep, usually in stage 1 nonREM sleep. 

 

SOREMP

Sleep Onset REM Period. A REM period that occurs at sleep onset. This is atypical, as most people transition from wakefulness to stage 1 nonREM sleep. The presence of SOREMPs during an MSLT or "nap test" indicates the potential for a diagnosis of narcolepsy. Learn more: 

 

SPO2

Blood Oxygen Saturation. This is expressed as a chemical equation: The S stands for saturation, the P stands for pulse, and the O2 stands for oxygen. A fingertip sensor known as a pulse oximeter is used during a sleep study to measure trends in both blood oxygen saturation and pulse throughout the test. 

 

SWS

Slow Wave Sleep. This is another name for stage 3 nonREM sleep, delta sleep, or deep sleep. Brain waves during slow wave sleep show a distinctive delta wave pattern. It is during this stage of sleep that the brain releases growth hormone into the bloodstream to help heal the body at the cellular level. 

 

U

UARS

Upper Airway Resistance Syndrome. A form of sleep-breathing disorder in which there are increases in resistance to airflow in the upper airway during sleep; this leads to brief arousals and daytime fatigue, even in the absence of apneas. Learn more: 

 

W

WASO

Wake After Sleep Onset. The total amount of time spent awake after sleep has been initiated. WASO is a marker of sleep fragmentation, in which people fall asleep, then awaken frequently all night during and between each sleep cycle. A high WASO index on a sleep study may reveal the cause of someone's excessive daytime sleepiness or confirm the presence of other sleep disorders. Learn more: 

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