How OSA and CSA Differ at a Physiological Level
Obstructive sleep apnea (OSA) and central sleep apnea (CSA) both cause breathing pauses during sleep, but their underlying mechanisms are completely different. In OSA, the airway physically collapses — the muscles supporting the soft palate, tongue base, and throat relax to the point where the passage narrows or closes entirely. The brain continues sending the signal to breathe, but air cannot get through. This physical obstruction is what causes the characteristic snoring sound and the gasping arousals.
Central sleep apnea is not an airway problem at all. In CSA, the brainstem fails to send adequate signals to the respiratory muscles, so breathing simply stops for a period because the body receives no instruction to continue it. There is no blockage, no snoring, and often no gasping — just silent pauses in breathing. CSA is often associated with heart failure, opioid use, or high-altitude exposure. It can also appear as treatment-emergent central apnea in people who begin CPAP therapy for OSA. Understanding this physiological distinction is the foundation of every treatment decision that follows.
Symptoms That Help Distinguish OSA From CSA
Clinically separating OSA from CSA based on symptoms alone is difficult, but certain patterns point in different directions. OSA is strongly associated with loud, habitual snoring — snoring that a bed partner notices most nights, often interrupted by gasping or choking. Excessive daytime sleepiness, morning headaches, and waking with a dry or sore throat are also common in OSA. Many people with OSA are overweight, have a thick neck, or are told they sleep with their mouth open.
CSA is quieter. Because the airway is patent, snoring is absent or mild. Instead, patients may describe non-restorative sleep, frequent nighttime awakenings, and in some cases, conscious awareness of not breathing. Insomnia is more prevalent in CSA than in OSA. Patients with underlying heart failure may notice that their symptoms worsen when lying flat. Neither condition is reliably diagnosed from symptoms alone, which is why objective testing is essential.
Diagnosing Both Conditions: The Role of Polysomnography
The gold-standard diagnostic test for both OSA and CSA is in-lab polysomnography (PSG) — an overnight study that simultaneously records brain activity (EEG), eye movements, muscle activity, heart rhythm, airflow, respiratory effort, and blood oxygen saturation. The simultaneous measurement of airflow and respiratory effort is what differentiates the two types: in OSA, effort is present but airflow stops; in CSA, both effort and airflow stop together.
The study produces an Apnea-Hypopnea Index (AHI), which counts the number of complete breathing pauses (apneas) and partial reductions in airflow (hypopneas) per hour of sleep. An AHI above 5 with symptoms, or above 15 regardless of symptoms, meets criteria for a clinical diagnosis. Home sleep apnea tests can detect OSA in straightforward cases but are not adequate for diagnosing CSA, as they cannot measure the neural respiratory effort signals needed to classify apnea type. If your physician suspects CSA, in-lab testing is required.
Treatment Paths: CPAP for OSA, Adaptive Servo-Ventilation for CSA
Because the mechanisms differ, the treatments differ substantially. For moderate to severe OSA, continuous positive airway pressure (CPAP) is the first-line treatment. CPAP delivers a pressurized airflow that acts as a pneumatic splint, physically holding the upper airway open and preventing the soft tissue collapse that causes obstruction. It does not help central apnea because the problem is not a collapsed airway — it is absent respiratory drive.
CSA is treated with adaptive servo-ventilation (ASV), a more sophisticated device that monitors the patient's breathing pattern in real time and delivers pressure support precisely when it detects an absent or insufficient breath. ASV effectively normalizes the irregular breathing rhythm seen in CSA. For treatment-emergent central apnea (where CPAP use itself triggers central events), ASV is often the preferred upgrade. Bi-level positive airway pressure (BiPAP) is used in some CSA cases, particularly those related to neuromuscular disease. The choice of device must be guided by a sleep medicine physician who has reviewed the diagnostic study.
When an Anti-Snoring Mouthpiece Is Appropriate (OSA Only)
Oral appliances such as mandibular advancement devices (MADs) are clinically appropriate for OSA — not for CSA. This distinction matters because using an oral appliance in someone with undiagnosed central apnea will eliminate any snoring but leave the central events entirely untreated, creating a false sense of security. For OSA, however, the evidence for MADs is strong. The Journal of Clinical Sleep Medicine and the American Academy of Sleep Medicine both recognize oral appliances as effective therapy for mild to moderate OSA and as an alternative for patients with severe OSA who cannot tolerate CPAP.
MADs work by advancing the lower jaw slightly forward during sleep, which increases the cross-sectional area behind the tongue and reduces the propensity for soft tissue collapse. The Snorple mouthpiece combines mandibular advancement with tongue stabilization in a dual-mechanism design that addresses both common anatomical contributors to airway obstruction in OSA. If you have already been tested and confirmed to have OSA without a significant central component, an oral appliance is a practical, non-invasive nightly option. If you have not been tested and you snore loudly with witnessed apneas, a diagnostic sleep study should come first.
Take Action Tonight
If snoring affects you or someone you love, the solution does not have to be complicated or expensive. The Snorple mouthpiece uses dual MAD and TSD technology to keep your airway open naturally while you sleep.