Not All Sleep Apnea Is the Same
Sleep apnea is often spoken about as a single condition, but there are three distinct types — and understanding which type you have is essential because they have different causes, different presentations, and very different treatment approaches. The two main forms are obstructive sleep apnea (OSA) and central sleep apnea (CSA), with a third form — complex or mixed sleep apnea — combining elements of both.
Obstructive Sleep Apnea (OSA)
OSA is by far the most common form, accounting for approximately 84% of all sleep apnea cases. It occurs when the muscles of the throat and upper airway relax too much during sleep, causing physical collapse of the airway. Despite continued breathing effort — the chest and abdomen still move — no air can pass through the blocked passage.
OSA is strongly associated with excess weight, jaw anatomy, enlarged tonsils, and age-related loss of airway muscle tone. Its hallmark is loud snoring, often followed by gasping or choking as the airway reopens. The primary treatments are CPAP, oral appliance therapy, weight loss, and in some cases surgery.
Central Sleep Apnea (CSA)
Central sleep apnea accounts for approximately 0.4–4% of sleep apnea cases. It occurs when the brain fails to send the proper signals to the muscles that control breathing. Unlike OSA, there is no airway obstruction — the airway is open, but no breathing effort is made. The chest and abdomen do not move during CSA events.
CSA is most commonly associated with heart failure, stroke, opioid or narcotic medication use, high-altitude sleeping, and brainstem injury. It is less likely to produce loud snoring and more likely to present with insomnia, frequent awakenings, and central pauses in breathing. Treatment focuses on addressing the underlying cause and may include adaptive servo-ventilation (ASV), supplemental oxygen, or medication adjustments.
Complex or Mixed Sleep Apnea
Some patients have both obstructive and central components. This is called complex or mixed sleep apnea. It is most commonly identified when patients who appear to have OSA on initial testing develop or reveal central apneas once CPAP is started — a pattern known as treatment-emergent central sleep apnea. Managing mixed sleep apnea typically requires more advanced titration and may involve different pressure support modes.
Why the Distinction Matters
The type of sleep apnea you have directly determines which treatments are appropriate. Oral appliance therapy — which works by physically repositioning the jaw to prevent airway collapse — is effective for obstructive sleep apnea but does not address central apneas. Before starting any treatment, it is essential to have a proper sleep study interpreted by a sleep medicine physician who can differentiate between OSA and CSA and identify any mixed component.