Sleep Apnea (Obstructive and Central) Glossary of Terms

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Abnormal: Not normal. Deviating from the usual structure, position, condition, or behavior. In referring to a growth, abnormal may mean that it is cancerous or premalignant (likely to become cancer).

Airway: The path air follows to get into and out of the lungs. The mouth and nose are the normal entry and exit ports. Entering air then passes through the back of the throat (pharynx), continues through the voice box (larynx), down the trachea, and finally out the branching tubes known as bronchi.

Airway obstruction: Partial or complete blockage of the breathing tubes to the lungs. Obstruction of the airway can be due to different causes including foreign bodies, allergic reactions, infections, anatomical abnormalities and trauma.
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Ambient: Surrounding, present on all sides; encompassing. As, the ambient noise is deafening, or the ambient light is blinding. From the Latin "ambire" meaning "to go around."

Anatomy: The study of form. Gross anatomy involves structures that can be seen with the naked eye. It is as opposed to microscopic anatomy (or histology) which involves structures seen under the microscope. Traditionally, both gross and microscopic anatomy have been studied in the first year of medical school in the U.S. The most celebrated textbook of anatomy in the English-speaking world is Gray's Anatomy, still a useful reference book. The word "anatomy" comes from the Greek ana- meaning up or through + tome meaning a cutting. Anatomy was once a "cutting up" because the structure of the body was originally learned through dissecting it, cutting it up. The abbreviation for anatomy is anat.

Anxiety: A feeling of apprehension and fear characterized by physical symptoms such as palpitations, sweating, and feelings of stress. Anxiety disorders are serious medical illnesses that affect approximately 19 million American adults. These disorders fill people's lives with overwhelming anxiety and fear. Unlike the relatively mild, brief anxiety caused by a stressful event such as a business presentation or a first date, anxiety disorders are chronic, relentless, and can grow progressively worse if not treated.
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Apnea: An apnea is a period of time during which breathing stops or is markedly reduced. There are two types of apneas, the more common obstructive sleep apnea and the less common central sleep apnea.
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Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle. It's measurement is recorded by two numbers. The first (systolic pressure) is measured after the heart contracts and is highest. The second (diastolic pressure) is measured before the heart contracts and lowest. A blood pressure cuff is used to measure the pressure. Elevation of blood pressure is called "hypertension".

Brain: That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres."

Breathing: The process of respiration, during which air is inhaled into the lungs through the mouth or nose due to muscle contraction, and then exhaled due to muscle relaxation.

Carbon dioxide: A gas which is the byproduct of cellular metabolism and which collects in the tissues, is cleared from the tissues by the blood within the veins, is carried by the hemoglobin in the red blood cells, and removed from the body via the lungs in the exhaled air. Abbreviated CO2.

Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.
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Co-morbid: Pertaining to two or more disorders simultaneously.

Congenital: Present at birth. A condition that is congenital is one that is present at birth. There are numerous uses of "congenital" in medicine. There are, for example, congenital abnormalities. (For more examples, see below.)
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Congestion: An abnormal or excessive accumulation of a body fluid. The term is used broadly in medicine. Examples include nasal congestion (excess mucus and secretions in the air passages of the nose) seen with a common cold and congestion of blood in the lower extremities seen with some types of heart failure.

Continuous positive airway pressure: See: CPAP.

CPAP: Continuous positive airway pressure. CPAP is an effective treatment for obstructive sleep apnea.
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Diagnosis: 1 The nature of a disease; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies. 3 The identification of any problem. The diagnosis was a plugged IV.
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ECG: Abbreviation for electrocardiogram or EKG. The K is from "kardio" (in German).

EEG: Electroencephalogram, e technique for studying the electrical current within the brain. Electrodes are attached to the scalp. Wires attach these electrodes to a machine which records the electrical impulses. The results are either printed out or displayed on a computer screen. Electroencephalogram is abbreviated EEG.
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Electrocardiogram: A recording of the electrical activity of the heart. An electrocardiogram is a simple, non-invasive procedure. Electrodes are placed on the skin of the chest and connected in a specific order to a machine that, when turned on, measures electrical activity all overaround the heart. Output is usually in the form of a long scroll of paper displaying a printed graph of activity. Newer models output the data directly to a computer and screen, although a print-out may still be made.
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Electroencephalogram: A study of electrical current within the brain. Electrodes are attached to the scalp. Wires attach these electrodes to a machine which records the electrical impulses. The results are either printed out or displayed on a computer screen. Electroencephalogram is abbreviated EEG.
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Essential: 1. Something that cannot be done without.
2. Required in the diet, because the body cannot make it. As in an essential amino acid or an essential fatty acid.
3. Idiopathic. As in essential hypertension. "Essential" is a hallowed term meaning "We don't know the cause."

Fatigue: A condition characterized by a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a feeling of weariness and tiredness. Fatigue can be acute and come on suddenly or chronic and persist.
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FDA: The Food and Drug Administration, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services.
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Food and Drug Administration: The FDA, an agency within the U.S. Public Health Service, which is a part of the Department of Health and Human Services.
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Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest.
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Heart attack: The death of heart muscle due to the loss of blood supply. The loss of blood supply is usually caused by a complete blockage of a coronary artery, one of the arteries that supplies blood to the heart muscle. Death of the heart muscle, in turn, causes chest pain and electrical instability of the heart muscle tissue.
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Heart disease: Any disorder that affects the heart. Sometimes the term "heart disease" is used narrowly and incorrectly as a synonym for coronary artery disease. Heart disease is synonymous with cardiac disease but not with cardiovascular disease which is any disease of the heart or blood vessels. Among the many types of heart disease, see, for example: Angina; Arrhythmia; Congenital heart disease; Coronary artery disease (CAD); Dilated cardiomyopathy; Heart attack (myocardial infarction); Heart failure; Hypertrophic cardiomyopathy; Mitral regurgitation; Mitral valve prolapse; and Pulmonary stenosis.

Heart failure: Inability of the heart to keep up with the demands on it and, specifically, failure of the heart to pump blood with normal efficiency. When this occurs, the heart is unable to provide adequate blood flow to other organs such as the brain, liver and kidneys. Heart failure may be due to failure of the right or left or both ventricles. The signs and symptoms depend upon which side of the heart is failing. They can include shortness of breath (dyspnea), asthma due to the heart (cardiac asthma), pooling of blood (stasis) in the general body (systemic) circulation or in the liver's (portal) circulation, swelling (edema), blueness or duskiness (cyanosis), and enlargement (hypertrophy) of the heart.
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Heart rate: The number of heart beats per unit time, usually per minute. The heart rate is based on the number of contractions of the ventricles (the lower chambers of the heart). The heart rate may be too fast (tachycardia) or too slow (bradycardia). The pulse is bulge of an artery from the wave of blood coursing through the blood vessel as a result of the heart beat. The pulse is often taken at the wrist to estimate the heart rate.

High blood pressure: Also known as hypertension, high blood pressure is, by definition, a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90.
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Hygiene: The science of preventive medicine and the preservation of health. From the name of Hygeia, the daughter of Asklepios, the Greek god of medicine (whose staff with entwined snake is the symbol of medicine). Asklepios (known to the Romans as Aesculapius) had a number of children including not only Hygeia but also Panaceia, the patroness of clinical medicine. Hygeia also followed her father into medicine. As the patroness of health, Hygeia was charged with providing a healthy environment to prevent illness. In Greek, "hygieia" means health.

Hypertension: High blood pressure, defined as a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90.
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Hypopnea: Literally, underbreathing. Breathing that is shallower or slower than normal. Hypopnea is distinct from apnea in which there is no breathing.
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Hypoventilation: The state in which a reduced amount of air enters the alveoli in the lungs, resulting in decreased levels of oxygen and increased levels of carbon dioxide in the blood. Hypoventilation can be due to breathing that is too shallow (hypopnea) or too slow (bradypnea) or to diminished lung function.
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Injury: Harm or hurt. The term "injury" may be applied in medicine to damage inflicted upon oneself as in a hamstring injury or by an external agent on as in a cold injury. The injury may be accidental or deliberate, as with a needlestick injury. The term "injury" may be synonymous (depending on the context) with a wound or with trauma.

Insomnia: The perception or complaint of inadequate or poor-quality sleep because of one or more of the following: difficulty falling asleep; waking up frequently during the night with difficulty returning to sleep; waking up too early in the morning; or unrefreshing sleep. Insomnia is not defined by the number of hours of sleep a person gets or how long it takes to fall asleep. Individuals vary normally in their need for, and their satisfaction with, sleep. Insomnia may cause problems during the day, such as tiredness, a lack of energy, difficulty concentrating, and irritability.
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Jaw: The bones below the mouth (the mandible) and the bone above the mouth just above the mouth (the maxilla). The word jaw comes from the Anglo-Saxon ceowan meaning to chew.

Limb: The arm or leg.

Lungs: The lungs are a pair of breathing organs located with the chest which remove carbon dioxide from and bring oxygen to the blood. There is a right and left lung.

Medical history: 1. In clinical medicine, the patient's past and present which may contain clues bearing on their health past, present, and future. The medical history, being an account of all medical events and problems a person has experienced, including psychiatric illness, is especially helpful when a differential diagnosis is needed.
2. The history of medicine.

Memory: 1. The ability to recover information about past events or knowledge. 2. The process of recovering information about past events or knowledge. 3. Cognitive reconstruction. The brain engages in a remarkable reshuffling process in an attempt to extract what is general and what is particular about each passing moment.
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Modafinil: An oral drug first approved by the FDA in 1998 for the treatment of narcolepsy, a condition in which there is an uncontrollable desire to sleep. Modafinil promotes wakefulness. In 2004 the FDA also approved modafinil for the treatment of obstructive sleep apnea and sleeping problems caused by shift work.
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Mouth: 1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.

MPH: Master of Public Health (a master's degree in this field of medicine).

Nasal: Having to do with the nose. Nasal drops are intended for the nose, not (for example) the eyes. The word "nasal" came from the Latin "nasus" meaning the nose or snout.

Nasal septum: The dividing wall within the nose. The nasal septum runs down the middle of the nose creating two sides to the nose, each containing a passageway that ends in a nare (nostril).
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Neck: The part of the body joining the head to the shoulders. Also, any narrow or constricted part of a bone or organ that joins its parts as, for example, the neck of the femur bone.

Neurologist: A doctor who specializes in the diagnosis and treatment of disorders of the nervous system.

Neuromuscular: Pertaining to both nerves and muscles, as in neuromuscular blockade by an anesthetic agent, the neuromuscular junction (the meeting place of a nerve and a muscle fiber), and neuromuscular transmission (the transfer of "information" from the nerve to the muscle).

Nose: The external midline projection from the face.
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Obesity: The state of being well above one's normal weight.
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Objective: In a microscope, the objective (also called the objective lens) is the lens nearest to the object being examined whereas the lens closest to the eye is termed the ocular (the eyepiece).
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Obstruction: Blockage of a passageway. See, for example: Airway obstruction; Intestinal obstruction.

Obstructive sleep apnea (OSA): Sleep apnea is a breathing disorder characterized by brief interruptions of breathing during sleep. It owes its name to a Greek word, apnea, meaning "want of breath."
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Oxygen: A colorless, odorless and tasteless gas that makes up about 20% of the air we breathe (and at least half the weight of the entire solid crust of the earth) and which combines with most of the other elements to form oxides. Oxygen is essential to human, animal and plant life.
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Oxygenation: The addition of oxygen to any system, including the human body. Oxygenation may also refer to the process of treating a patient with oxygen, or of combining a medication or other substance with oxygen.
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Palate: The roof of the mouth. The front portion is bony (hard palate), and the back portion is muscular (soft palate).

Pharyngeal: Having to do with the throat (pharynx).

Pharynx: The hollow tube about 5 inches long that starts behind the nose and ends at the top of the trachea (windpipe) and esophagus (the tube that goes to the stomach).

Polysomnography: Continuous recording of specific physiologic variables during sleep. Polysomnography typically records brain wave changes (electroencephalogram), eye movements (electrooculogram), muscle tone (electromyogram), respiration, electrocardiogram (EKG), and leg movements.

Positive pressure ventilation: The provision of oxygen under pressure by a mechanical respirator, a machine designed to improve the exchange of air between the lungs and the atmosphere. The device is basically designed for administering artificial respiration, especially for a prolonged period, in the event of inadequate spontaneous ventilation or respiratory paralysis.
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Primary care: The "medical home" for a patient, ideally providing continuity and integration of health care. All family physicians and most pediatricians and internists are in primary care. The aims of primary care are to provide the patient with a broad spectrum of care, both preventive and curative, over a period of time and to coordinate all of the care the patient receives.

Provigil: Brand name of the drug modafinil. See: Modafinil.

Pulmonary: Having to do with the lungs. (The word comes from the Latin pulmo for lung).

Pulmonary hypertension: High blood pressure in the pulmonary artery that conveys blood from the right ventricle to the lungs. The pressure in the pulmonary artery is normally low compared to that in the aorta. Pulmonary hypertension can irrevocably damage the lungs and cause failure of the right ventricle.
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Referral: The recommendation of a medical or paramedical professional. If you get a referral to ophthalmology, for example, you are being sent to the eye doctor. In HMOs and other managed care schemes, a referral is usually necessary to see any practitioner or specialist other than your primary care physician (PCP), if you want the service to be covered. The referral is obtained from your PCP, who may require a telephone or office consultation first.
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Remedy: Something that consistently helps treat or cure a disease. From the Latin "remedium" meaning that which heals again (and again).
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Respiratory: Having to do with respiration, the exchange of oxygen and carbon dioxide. From the Latin re- (again) + spirare (to breathe) = to breathe again.

Respiratory rate: The number of breaths per minute or, more formally, the number of movements indicative of inspiration and expiration per unit time. In practice, the respiratory rate is usually determined by counting the number of times the chest rises or falls per minute. By whatever means, the aim is to determine if the respirations are normal, abnormally fast (tachypnea), abnormally slow (bradypnea), or nonexistent (apnea).

Rule out: A term much used in medicine, meaning to eliminate or exclude something from consideration. The ACB (albumin cobalt binding) test helps rule out a heart attack in the differential diagnosis of severe chest pain.

Sedative: A drug that calms a patient down, easing agitation and permitting sleep. Sedatives generally work by modulating signals within the central nervous system. These sedatives can dangerously depress important signals needed to maintain heart and lung function if they are misused or accidentally combined, as in the case of combining prescription sedatives with alcohol. Most sedatives also have addictive potential. For these reasons, sedatives should be used under supervision, and only as needed.

Septum: A word borrowed from the Latin "saeptum" meaning a "dividing wall or enclosure."

Sleep: The body's rest cycle.
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Sleep apnea: The temporary stoppage of breathing during sleep, often resulting in daytime sleepiness. Apnea is a Greek word that means "want of breath."
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Sleep hygiene: A series of practices and non-medical treatments for insomnia. Sleep hygiene includes simple steps that may improve initiation and maintenance of sleep, such as maintaining a regular sleep schedule, making the bedroom an inviting place to sleep, avoiding alcohol or smoking prior to going to bed, and exercising regularly (but not in the 4-5 hours prior to bedtime).

Snoring: A rough rattling noise made on inspiration during sleep by vibration of the soft palate (the back of the roof of the mouth) and the uvula (the prominent structure dangling down at the back of the mouth).
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Soft palate: The muscular part of the roof of the mouth. The soft palate is directly behind the hard palate. It lacks bone and so is soft.

Stroke: The sudden death of some brain cells due to a lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain. A stroke is also called a cerebrovascular accident or, for short, a CVA.
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Surgeon: A physician who treats disease, injury, or deformity by operative or manual methods. A medical doctor specialized in the removal of organs, masses and tumors and in doing other procedures using a knife (scalpel). The definition of a "surgeon" has begun to blur in recent years as surgeons have begun to minimize the cutting, employ new technologies that are "minimally invasive," use scopes, etc.
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Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office.
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Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease.
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Therapy: The treatment of disease.
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Throat: The throat is the anterior (front) portion of the neck beginning at the back of the mouth, consisting anatomically of the pharynx and larynx. The throat contains the trachea and a portion of the esophagus.

Tongue: The tongue is a strong muscle anchored to the floor of the mouth. It is covered by the lingual membrane which has special areas to detect tastes.
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Tonsils: Small masses of lymphoid tissue at the back of the throat, on either side of the throat.

Trauma: Any injury, whether physically or emotionally inflicted. "Trauma" has both a medical and a psychiatric definition. Medically, "trauma" refers to a serious or critical bodily injury, wound, or shock. This definition is often associated with trauma medicine practiced in emergency rooms and represents a popular view of the term. In psychiatry, "trauma" has assumed a different meaning and refers to an experience that is emotionally painful, distressful, or shocking, which often results in lasting mental and physical effects.
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Trigger: Something that either sets off a disease in people who are genetically predisposed to developing the disease, or that causes a certain symptom to occur in a person who has a disease. For example, sunlight can trigger rashes in people with lupus.

Uvula: The small piece of soft tissue that can be seen dangling down from the soft palate over the back of the tongue. The uvula is described variously shaped like a U, a tear or a grape. Its name comes from the Latin word for "grape," uva.
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Ventilation: The exchange of air between the lungs and the atmosphere so that oxygen can be exchanged for carbon dioxide in the alveoli (the tiny air sacs in the lungs).
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Vocal cord: One of two small bands of muscle within the larynx. These muscles vibrate to produce the voice. The vocal cords form a "V" inside the larynx, a 2-inch-long, tube-shaped organ in the neck:

Weight loss: Weight loss is a decrease in body weight resulting from either voluntary (diet, exercise) or involuntary (illness) circumstances. Most instances of weight loss arise due to the loss of body fat, but in cases of extreme or severe weight loss, protein and other substances in the body can also be depleted. Examples of involuntary weight loss include the weight loss associated with cancer, malabsorption (such as from chronic diarrheal illnesses ), and chronic inflammation (such as with rheumatoid arthritis).