Glossary of Terms

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.

An apnea event
Defined as a cessation of ventilation(breathing) for 10 seconds or longer.

Apnea Diagnosis
Occurs when a person experiences 30 or more apnea episodes during a seven hour sleep period.

Central Sleep Apnea
A sleep disorder in which the airway is not blocked but the brain fails to signal the muscles to breathe.

Continuous Positive Air Pressure Machine used to treat sleep apnea. During sleep, the patient wears a face mask connected to a pump that forces air into the nasal passages to overcome obstructions in the airway, forcing the airway to remain open.

Occurs when there is a partial obstruction somewhere in the airflow. It involves a decrease in oxygen levels in the blood (oxygen desaturation-uptake of greater than 4%).

Obstructive Sleep Apnea (OSA)
During sleep, the muscles in the throat relax and the tongue is sucked against the throat blocking the airway.The entire upper airway is blocked causing air flow to stop. Air (and oxygen) cannot flow into the lungs. When the oxygen level in the brain becomes low enough, the sleeper partially awakens, the obstruction in the throat clears, and the flow of air starts again – usually with a loud gasp or snort. People with untreated apnea are generally not aware of the awakenings but only of being sleepy during the day. Loud snoring, mixed with periods of silence (apnea), is typical but is not always present, especially in children.

Oral Appliance (OA)
Oral appliances (OA) that treat snoring , UARS, and OSA are devices worn in the mouth similar to sports mouth guards or orthodontic retainers. They are made of plastic and fit partially or completely within the mouth.

Oral Appliance Therapy (OAT)
Oral appliance therapy the 1st line of treatment to be considered for patients with mild to moderate sleep apnea who either prefer it to CPAP or unable to successfully use CPAP.

RDI (Respiratory Disturbance Index ) / AHI (Apnea-Hypopnea Index)
Average number of apneas plus hypopneas combined per hour of sleep.

During sleep, muscles relax in the back of the throat narrowing the airway to a smaller opening. While breathing, air is forced through this smaller opening causing vibrations known as snoring.

Temporomandibular joint

Temporomandibular joint disorder

UARS- Upper Airway Resistance Syndrome
This condition lies midway between benign snoring and true OSA. People with UARS suffer many of the symptoms of OSA but sleep testing results lack evidence demonstrating true apneas or oxygen desaturation.


1100 SHERMAN AVE., SUITE 103 | NAPERVILLE, IL | PHONE: 630.369.5508