<unk>  is caused when the<unk>  airway narrows without closing. Consequently, airflow is either reduced or compensated for through an increase in inspiratory efforts. This increased activity in inspiratory muscles leads to the arousals during sleep which patients may or may not be aware of. A typical<unk>  patient is not obese and possesses small jaws, which can result in a smaller amount of space in the nasal airway and behind the base of the tongue. Patients may have other anatomical abnormalities that can cause<unk>  such as deviated septum, inferior turbinate hypertrophy, a narrow hard palate that reduces nasal volume, enlarged tonsils, or nasal valve collapse.<unk>  affects equal numbers of males and females. Why some patients with airway obstruction present with<unk>  and not OSA is thought to be caused by alterations in nerves located in the palatal mucosa.<unk>  patients have largely intact and responsive nerves, while OSA patients show clear impairment and nerve damage. Functioning nerves in the palatal mucosa allow<unk>  patients to more effectively detect and respond to flow limitations before apneas and hypopneas can occur. Patients with intact nerves are able to dilate the genioglossus muscle, a key compensatory mechanism utilized in the presence of airway obstruction. What damages the nerves is not definitively known, but it is hypothesized to be caused by the long term effects of gastroesophageal reflux and/or snoring.
Upper airway resistance syndrome
Central hypoventilation syndrome
Obesity hypoventilation syndrome
Hyperventilation syndrome
Reactive airway disease
Eustachian tube dysfunction
Cardiac asthma
Yokkaichi asthma