Understanding Sleep Disorders and Their Symptoms
Ideally, humans would sleep through the night without any interruptions or wakings. This is rarely the case however, as almost all of us experience some sleep interruptions, which are known as arousals.
Sleep arousals are a natural reaction to a potential threat. These reflexes alert the body from deep sleep to a state of readiness. This reflex is left over from our ancestral times, meant to alert us when things that went “bump in the night” as a warning that there may be imminent danger.
It’s normal to experience brief periods of interruption during sleep, which can be triggered by anything from a strange noise to a bed partners shifting position. But when these arousal become too frequent or lengthy, they are considered to be sleep disorders.
There are a number of disorders that can keep a person from obtaining quality sleep. The disorders that dental sleep medicine addresses are the most frequent: disruptive snoring, hypopnea and obstructive sleep apnea. All of these conditions involve obstructions to the breathing process. The treatments provided involve the use of oral appliances. Similar devices can be used to address the pain associated with TMJ disorders, which is also within the realm of dental sleep medicine.
An apnea is defined as the complete cessation of breathing for a period of at least 10 seconds. A hypopnea is a decrease in breath volume of 30 to 50 percent that is associated with a drop in oxygen saturation of at least four percent, or which creates an arousal response. The apnea/hypopnea index (AHI) is a measure of how many of each of these events a patient has per hour of sleep.
Another measure frequently used to classify sleep disorders is the respiratory disturbance index (RDI), which records respiratory events, this also includes RERAs. An RERA is an arousal from sleep that technically does not meet the definition of an apnea or hypopnea, but still disrupts sleep.