Glossary of Terms

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ACROMEGALY A curious condition of increased growth hormone production in adults that can present as an obstructive sleep apnoea.

ALCOHOL While it can help relaxation, it also relaxes the throat muscles and so contribute to snoring and obstructive apnoea.

ANAESTHESIA A dangerous time for people with sleep apnoea. The anaesthetic drugs, pre-medication sedatives and post operative pain relief drugs can all worsen sleep apnoea.Make sure your surgeon and anaesthetist are aware ahead of any operation if you have sleep apnoea.

APNOEA (ap-nee-ah)

A pause in breathing; conventionally more than 10 seconds. From the Greek a (without) ponea (breath).

AUTO CPAP MACHINE or APAP A clever, computerised CPAP machine that adjusts its pressure automatically as needed. Many clinics are now issuing APAP machines to patients instead of CPAP, as these machines can be set to a fixed pressure, a wide or narrow pressure range or left fully automatic, to best suit the needs of particular patients.


BECONASE Nasal steroid spray. Extremely useful to reduce nasal inflammation and swelling. Can be used for long periods. Flixonase is very similar but is prescription only.


CATAPLEXY (cat-ar-plex-ee)

Sudden loss of muscle power, with collapse onto the ground, but no loss of consciousness. A feature of narcolepsy that occurs particularly during moments of excitement or anticipation.

CENTRAL APNOEA Episodes of stopping breathing, not due to obstruction of the upper airway, but due to the brain simply failing to ask for a breath. Much less common than obstructive sleep apnoea and needs nasal intermittent positive pressure ventilation (NIPPV) as a treatment, rather than nasal CPAP.

CHEYNE-STOKES-BREATHING Breathing that cycles up and down, also know as periodic breathing. Found in people with heart failure and neurological problems.

CHIN SUPPORT / STRAP A strap or loop of material passing under the chin, sometimes needed to hold the mouth closed to prevent air leaks during nasal CPAP or nasal ventilation.


CYANOSIS (sigh-an-o-sis)

The bluey colour one goes when low in oxygen.


DENTAL DEVICE see Mandibular Advancement Device.

DESATURATIONS see Hypoxic Dips.

DIAPHRAGM (die-er-fram)

Main muscle of breathing between the bottom of the chest and stomach; pulls the lungs out, thus drawing in air.


EAR Foam earplugs, the most comfortable available, but not as good as wax ones. They are little foam cylinders that are rolled up into a thin core which then slowly expands after insertion into the ear canal. Like all earplugs, they take two or three nights to get used to. Available from most chemists.

ELECTRO-ENCEPHALOGRAM (EEG, most people only use the abbreviation). Recording of brain waves, required for sleep staging.

ELECTRO-MYOGRAM (EMG) Recording of muscle activity. Used as part of sleep staging.

ELECTRO-OCULOGRAM (EOG) Recording of eye movements, required for sleep staging to define rapid eye movement sleep (or dreaming sleep).

EPWORTH SLEEPINESS SCALE Eight questions asking about tendency to drop off at inappropriate times, used to gauge how sleepy someone is.


FLIXONASE see Beconase


HYPERCAPNIA (high-per-cap-nee-ah)

A raised level of carbon dioxide in the blood. This is the gas normally breathed out which will rise if breathing is inadequate. Usually measured by taking an arterial blood sample.

HYPERSOMNOLENCE (high-per-som-no-lence)

Technical expression for excessive sleepiness.

HYPNOGRAM (hip-no-gram)

The final print out of all the night sleep stages (REM and non-REM). HYPOPNOEA (high-pop-nee-ah)

A period of underbreathing, conventionally for more than 10 seconds.

HYPOTHRYOIDISM (high-po-thy-royd-ism)

Also known as myxoedema (mix-ee-dee-ma). When the thyroid gland fails to make enough thyroid hormone. Can present as obstructive sleep apnoea and snoring.

HYPOXIA (high-pox-ee-ar)

When the body is short of oxygen and therefore the level in the blood falls.

HYPOXIC DIPS (high-pox-ic)

The falls in oxygen levels, seen on the oximeter, that usually accompany apnoeas. Also know as desaturations, because when it is not hypoxic the blood is described as fully saturated with oxygen.


INSOMNIA (in-som-nee-ah)

Being awake when you want to be asleep. Often thought of as a problem,but may not be. Common if people try to spend too long in bed.


Jaw Adjustment Device.(Other common names for these devices are MAD (Mandibular Advancement Device) or MRD(Mandibular Repositioning Device).


LASER Used by surgeons as an alternative to a scalpel. Cuts and coagulates vessels (lessens bleeding) at the same time.

LASER ASSISTED UPPP (LAUP) Fancy version of a conventional UPPP, but unlikely to be any better.


MANDIBULAR ADVANCEMENT DEVICE (MAD) Intra-oral device worn at night to hold the mouth closed and the lower jaw forward. Increases the space behind the tongue, which lessens snoring and may help obstructive sleep apnoea. Obtained from dentists.

MANOMETER (man-om-eater)

Device to measure the pressure being delivered by a CPAP machine (usually measured in centimetres of water {cmH20} – where a common CPAP pressure is about 10).

MICRO AROUSALS Very brief “awakenings”, perhaps only seen when the brain waves (EEG) are being monitored.

MOVEMENT AROUSAL These are short awakenings with minor body movements of which the sleeper is unaware.

MUFFLES Wax ear plugs. Less comfortable than the foam ones but more effective. From most chemists.


NARCOLEPSY (nar-co-lep-si)

A cause of daytime sleepiness due to an inherited disorder of the control of dreaming sleep. Has to be differentiated from sleep apnoea, periodic leg movements and other rarer causes of daytime sleepiness.

NASAL CPAP (nasal see-pap)

The process of delivering a continuously raised airway pressure via a mask on the nose. Hence nasal Continuous Positive (as opposed to negative) Airway Pressure treatment.

NASAL CPAP SYSTEM ((parts of:))

Adam’s Circuit – alternative to the nose mask. Consists of nose plugs that fit at the entrance to the nose. Less stable than a mask – may be more comfortable.
Bubble Mask – a nasal CPAP mask, designed by ResCare in Australia, that looks like a bubble with a hole in it. Seals against the face better in some people.
Headgear – strap arrangement holding on the mask.
Mask – the bit going over the nose.
Mirage Mask – a particular make of nasal mask.
Nose Pads – foam pads to hold the mask at a certain distance off the bridge of the nose.
Pump or blower – main unit developing the pressure.
Ramp – the slow rise to full pressure after first turning on the machine, available from some manufacturers.
Softcap – type of headgear.
Vent Holes / Mask ports – the alternative to whisper swivels – the holes already present on the mask.
Whisper Swivel – one manufacturer’s arrangement to vent off the air from the mask end of the system.

NASAL INTERMITTENT POSITIVE PRESSURE VENTILATION (NIPPV) Overnight assisted breathing with a machine that intermittently inflates the lungs. In contrast to nasal CPAP which provides a constant pressure to hold open the upper airway.

NECK CIRCUMFERENCE One of the best predictors of whether there are upper airway problems during sleep. More than 16″ – could be a snorer, more than 17″ could have sleep apnoea. One can still have sleep apnoea with smaller necks but it is less common.

NOCTURIA (nock-tur-ee-ah)

Excessive urine production at night. Seen in sleep apnoea quite often.

NON REM SLEEP See sleep stages.


OBSTRUCTIVE SLEEP APNOEA (OSA) Episodes of stopping breathing at night due to obstruction of the upper airway from narrowing during sleep. Produces sleep disruption, and the daytime consequence of excessive sleepiness.

OTRIVINE Nasal spray to reduce congestion. Can only be used for up to five nights consecutively: therefore of most use during a cold. Can be obtained over the counter without prescription.

OXIMETER (ox-im-eater)

Monitoring device that continuously measures the level of oxygen (oxygen saturation) in the blood by measuring its colour: usually done with a clothes peg like clip on the finger or ear. A common way to analyse the overnight tracing is to count the number of dips in oxygen.


PALATE The soft tissue flap that hangs down the back of the throat attached to the roof of the mouth. The tip is also called the uvula. The whole structure is often called the soft palate to differentiate it from the roof of the mouth (a bony structure), also called the hard palate.

PANIC AROUSALS Episodes of awaking with sensation of panic. Sometimes due to bad dreams and stress, or as a consequence of waking and sensing the upper airway is blocked.

PERIODIC MOVEMENTS OF THE LEGS DURING SLEEP (PMLS) Also known as nocturnal myoclonus. A condition where the legs move every 40 seconds or so, producing brief arousals. Commonly seen in the first few weeks on nasal CPAP (not understood why). Another cause of daytime sleepiness.

PHARYNX (fa-rinx)

Essentially the throat area between the voice box and the back of the nose behind the tongue. A floppy muscular tube.

PICKWICKIAN SYNDROME An old term for large people with problems of underbreathing. Included a lot of diagnosis. No longer used by those that know!

POLYSOMNOGRAPHY (ply-som-nog-gra-fie)

Simply means a recording of lots of things during sleep. Has come to mean recording at least EEG, EMG and EDG all night.


REM SLEEP See sleep stages. RINATEC Nasal spray that reduces congestion and discharge. Can be used on a long term basis. Prescription only.


SCOLIOSIS A twisting of the spine that can limit lung expansion and lead to problems of underbreathing, which can be alleviated by overnight breathing support.

SILASTIC RING GASTROPLASTY An operation to limit eating (the last resort!), not very pleasant. If you overeat you are sick.

SLEEP STAGES Sleep is conventionally divided into five stages. Four of these are called non-REM sleep, the other is REM (or Rapid Eye Movement) sleep. REM sleep is when we dream, and the brain is virtually awake. Non_REM sleep is graded 1 to 4 and represents increasing depths of sleep. This is the sleep required to refresh, with the two deeper stages 3 and 4 called slow wave sleep.

SLOW WAVE SLEEP See sleep stages.

SNORING AROUSALS Sleep can be disturbed not only by actual episodes of stopping breathing, but also by snoring alone (when a big increase in breathing effort is required to overcome the narrowing of the upper airway that led to the snoring).

STRYCHNINE Has been tried to cure sleep apnoea! Works a bit, but there are worries that spouses might be tempted to give an overdose at 3 am when the snoring is particularly bad!


TONSILS Collection of tissues involved in fighting infection on the side walls of the throat, which usually melt away by the age of 8 or so, but may persist and partly block the pharynx or throat.

TRACHEOSTOMY (trak-ee-osto-mee)

Creating a hole into the windpipe from outside, just below the Adam’s apple. Sometimes needed in many different conditions, and used to be the main treatment for obstructive sleep apnoea (opened at night, closed during the day) to bypass the obstruction in the throat.


UPPER AIRWAY RESISTANCE SYNDROME A general term for obstructive sleep apnoea and heavy snoring. Used to describe the relationship between upper airway narrowing during sleep, sleep disruption, and the daytime consequences of excessive sleepiness.

UVULOPALATOPHARYNGOPLASTY Don’t bother with the pronunciation – say UPPP or U-triple P instead! The operation that cuts away part of the soft palate and side wall of the pharynx (or throat) in an attempt to reduce snoring volumes. Not very effective and extremely painful.