Sleep Medicine Acronyms (From APAP to Zzzz): Part 3, N-R

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 third section highlights terms that start with the letters N through R.

See also: 

Sleep Medicine Acronyms (N-R) 




Noninvasive Ventilation or Noninvasive Positive Pressure Ventilation. This refers to forms of respiratory therapy that people use by way of a mask delivery system to help them to breathe better independently. (By comparison, a ventilator is a respiratory device, inserted into the trachea, which breathes for someone.) PAP therapy (CPAP, BiPAP, APAP) and ASV all qualify as forms of NIV. Learn more: 



Nocturnal Polysomnogram or Polysomnogram. This is an overnight sleep study which takes place in the sleep clinic or lab environment; its purpose is to identify and diagnose sleep disorders. Learn more: 



NonREM sleep. The 3 stages of sleep when rapid-eye movement does not occur. These include sleep stages 1, 2, and 3 of the sleep cycle. Learn more: 




Oral Appliance Therapy. This refers to the various kinds of dental appliances that can be used to treat snoring, upper airway resistance, or sleep apnea. Some are maxillomandibular advancement (MMA) devices, while others restrict the movement of the tongue in order to keep the upper airway clear. Learn more: 



Obesity Hypoventilation Syndrome. Also known as Pickwickian syndrome, OHS is a sleep-breathing disorder common to obese people, in which failure to breathe deeply or rapidly enough results in dangerously low blood oxygen levels and high carbon dioxide levels in the blood, especially during sleep. Learn more: 



Obstructive Sleep Apnea or Obstructive Sleep Apnea Syndrome or Obstructive Sleep Apnea Hypoventilation Syndrome. This refers to a sleep-breathing disorder in which the upper airway becomes partially or completely blocked for at least 10 seconds while sleeping, leading to struggles to get adequate oxygen into the bloodstream. Those who suffer at least 5 or more of these pauses during sleep are diagnosed with OSA. Learn more: 



Positive Airway Pressure. This therapy, used for treating sleep apnea, delivers preset ranges of therapeutic air pressure for the user. It includes CPAP, APAP, BiPAP, and ASV therapies. Learn more: 



Periodic Leg Movements of Sleep or Periodic Leg Movement Disorder. Periodic leg movements of sleep can occur in most anyone. However, when they happen frequently in a pattern and are not the result of arousals due to apnea, they can turn into a disorder: the pattern interrupts sleep, leading to sleep deprivation, excessive daytime sleepiness, or other concerns. PLMD is similar to RLS, but it only happens during sleep, whereas RLS takes place during the day or at bedtime. Learn more: 




REM Behavior Disorder. A parasomnia in which the brain fails to paralyze the body's muscles during REM sleep, allowing the person (potentially and dangerously) to act out dreams. Learn more: 



Respiratory Disturbance Index. A metric used to measure the severity of sleep apnea. It is based on the total number (per hour) of complete obstructions  (apnea), partial obstructions (hypopnea) in breathing, and respiratory-effort related arousals (RERA), expressed as an average. Learn more: 



Rapid Eye Movement. This stage of sleep is considered "paradoxical" because the brain is often as active, or more active, at this time than during wake. It is identified by distinctive patterns of eye movement that occur during this stage. Learn more: 



Respiratory Effort Related Arousals. This are partial obstructions to the upper airway that occur during sleep but which do not last as long as apneas and which may not result in a reduction in blood oxygen levels. Learn more: 



Restless Leg Syndrome. This is a movement disorder of sleep which can also exhibit symptoms during the day. The symptoms include unusual twitching, spasming, or other unpleasant sensation in the legs (and sometimes the arms) that may require movement or massage to relieve. RLS happens during bedtime and can lead to delays in falling asleep. Learn more: 

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