Sleep Apnea 101

Differences Between Complex, Obstructive, and Central Sleep Apnea

Sleep apnea is a serious sleep disorder that affects millions of people worldwide. It is characterized by repeated interruptions in breathing during sleep, which can lead to various health complications if left untreated. There are three main types of sleep apnea: Obstructive Sleep Apnea (OSA), Central Sleep Apnea (CSA), and Complex Sleep Apnea (CompSA). Each type has distinct causes, symptoms, and treatment approaches. This article explores the differences between these types of sleep apnea, providing a comprehensive understanding of their unique characteristics.

Obstructive Sleep Apnea (OSA)

Loud Snoring


Obstructive Sleep Apnea is the most common form of sleep apnea. It occurs when the muscles in the back of the throat fail to keep the airway open. This obstruction can be caused by various factors, including:

  • Obesity: Excess weight, particularly around the neck, can increase pressure on the airway.
  • Anatomical Factors: Structural abnormalities such as a large tongue, tonsils, or uvula, or a deviated septum can narrow the airway.
  • Age and Gender: OSA is more common in older adults and males.
  • Lifestyle Factors: Alcohol consumption and smoking can contribute to muscle relaxation and airway obstruction.


The primary symptoms of OSA include:

  • Loud Snoring: Often accompanied by gasping, choking, or snorting sounds.
  • Daytime Sleepiness: Excessive daytime sleepiness and fatigue due to disrupted sleep cycles.
  • Morning Headaches: Frequent headaches upon waking.
  • Difficulty Concentrating: Cognitive impairments such as memory problems and difficulty concentrating.
  • Mood Changes: Irritability, depression, or anxiety.

Diagnosis and Treatment

ProSomnus® Sleep and Snore Device

OSA is typically diagnosed through a sleep study, known as polysomnography, which monitors various physiological parameters during sleep. Treatment options include:

  • Continuous Positive Airway Pressure (CPAP): The most common and effective treatment, involving a machine that delivers air pressure through a mask to keep the airway open.
  • Lifestyle Changes: Weight loss, avoiding alcohol and smoking, and changing sleep positions.
  • Oral Appliances: Devices that reposition the lower jaw and tongue to keep the airway open.
  • Surgery: In severe cases, surgical interventions may be necessary to remove or reduce tissue blocking the airway.

Central Sleep Apnea (CSA)


Central Sleep Apnea is less common than OSA and occurs when the brain fails to send proper signals to the muscles that control breathing. CSA can be caused by various conditions, including:

  • Heart Disorders: Congestive heart failure and atrial fibrillation can affect the brain’s ability to regulate breathing.
  • Neurological Disorders: Conditions such as stroke, brain tumors, and neurodegenerative diseases.
  • Opioid Use: Medications that affect the central nervous system can disrupt normal breathing patterns.
  • High Altitude: Exposure to high altitudes can temporarily cause CSA due to lower oxygen levels.


Symptoms of CSA can overlap with those of OSA but often include:

  • Cheyne-Stokes Respiration: A distinct breathing pattern characterized by a gradual increase and then decrease in breathing effort, followed by a period of apnea.
  • Shortness of Breath: Waking up with shortness of breath.
  • Poor Sleep Quality: Frequent awakenings during the night.
  • Daytime Sleepiness: Similar to OSA, individuals with CSA often experience excessive daytime sleepiness and fatigue.

Diagnosis and Treatment

Diagnosis of CSA also involves polysomnography to monitor breathing patterns and brain activity. Treatment options include:

  • Adaptive Servo-Ventilation (ASV): A device that adjusts air pressure based on detected breathing patterns, specifically designed for CSA.
  • CPAP: Can be effective in some cases, though it is more commonly used for OSA.
  • Medication: Certain medications can stimulate breathing or address underlying conditions contributing to CSA.
  • Addressing Underlying Conditions: Treating heart or neurological disorders that contribute to CSA.

Complex Sleep Apnea (CompSA)


Complex Sleep Apnea, also known as treatment-emergent central sleep apnea, occurs when a person has both OSA and CSA. It often becomes apparent when OSA is treated with CPAP, which then reveals underlying CSA. The exact mechanisms are not fully understood but may involve a combination of airway obstruction and central nervous system dysfunction.


Symptoms of CompSA can include those of both OSA and CSA:

  • Loud Snoring and Gasping: Typical of OSA.
  • Disrupted Breathing Patterns: Including periods of apnea without obstructive causes, indicative of CSA.
  • Daytime Sleepiness and Fatigue: Due to poor sleep quality from both types of apneas.
  • Cognitive Impairment and Mood Changes: As a result of chronic sleep disruption.

Diagnosis and Treatment

Cpap machine

Diagnosing CompSA requires a detailed sleep study to identify the presence of both obstructive and central events. Treatment strategies include:

  • CPAP or BiPAP: Initial treatment with CPAP, and if CSA becomes apparent, switching to bilevel positive airway pressure (BiPAP).
  • ASV: Often used if CPAP or BiPAP is ineffective, ASV adjusts pressure based on the detection of breathing patterns and is specifically designed for complex cases.
  • Comprehensive Management: Addressing both obstructive and central components, including lifestyle changes, managing underlying conditions, and potentially using a combination of devices and therapies.


Understanding the differences between Obstructive Sleep Apnea, Central Sleep Apnea, and Complex Sleep Apnea is crucial for accurate diagnosis and effective treatment. Each type of sleep apnea has unique causes and symptoms, requiring tailored treatment approaches to ensure optimal patient outcomes. As research continues and technology advances, the ability to manage and treat these conditions will improve, offering a better quality of life for those affected by sleep apnea.

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