Neurological Causes of Central Sleep Apnea: How the Brain Impacts Breathing During Sleep

Central sleep apnea (CSA) is a complex sleep disorder that occurs when the brain does not send the correct signals to the muscles responsible for breathing during sleep. Unlike obstructive sleep apnea, which is caused by a physical blockage of the airway, central sleep apnea is a neurological issue involving the brain's control over breathing. 

Understanding the neurological causes of central sleep apnea is essential because disruptions in brain function play a significant role in the development of this disorder. 

If left untreated, CSA can cause long-term complications, which is why it is important to be able to distinguish the symptoms of the disorder from other neurological disorders. Any symptoms require urgent medical attention and timely intervention to safeguard overall health and improve quality of life.

The Role of the Brain in Central Sleep Apnea

The brainstem is involved in regulating breathing during sleep. It connects the brain to the spinal cord and controls essential functions such as heartbeat and respiration. In CSA, this part of the brain fails to send signals to the respiratory muscles, leading to pauses in breathing during sleep. These pauses in breathing are known as apneas. They often present as altered brainstem activity and can interfere with the ventilatory control system. 

Impaired Chemoreceptor Response

Under normal conditions, the brainstem adjusts your breathing rate and depth in response to changes in carbon dioxide (CO2) levels in the blood. When carbon dioxide levels increase, the brainstem signals for increased breathing rate, while low CO2 levels lead to reduced breathing. However, in central sleep apnea, the signaling does not work correctly, and the body is unable to respond to changes in CO2 levels. 

This leads to periodic breathing or pauses in breathing during sleep, explaining why patients with CSA experience cycles of hyperventilation followed by apnea to try to normalise CO2 levels in the body.

Impact of Neurological Disorders and Conditions

Several neurological disorders and conditions can cause CSA by affecting the brainstem or neural pathways, which are responsible for controlling respiration. For example, stroke, brainstem lesions, and neurodegenerative diseases often result in an increased risk of developing CSA.  Cheyne-Stokes breathing, a form of central apnea, can be seen in patients with congestive heart failure or after a stroke. 

CSA is sometimes referred to as a neurological sleep apnea syndrome and underscores the importance of neurological evaluation in its diagnosis and treatment. This also distinguishes CSA from OSA, as CSA arises from complex brain-related factors while OSA is caused by physical obstructions.

Specific Neurological Disorders Linked to Central Sleep Apnea

Brainstem Lesions

Brainstem lesions are among the most significant neurological causes of CSA. The brainstem contains critical respiratory centers, including the pre-Bötzinger complex, which regulates the respiratory rhythm. Damage caused by ischemia, infarction, tumors, edema, or demyelinating diseases can disrupt these respiratory control centers. As a result, patients experience impaired signaling to respiratory muscles during sleep, leading to CSA. Recent studies using advanced imaging techniques, such as diffusion tensor imaging (DTI), show that the extent of microscopic brainstem damage directly affects the severity of CSA.

Heart Failure and Its Neurological Implications

Congestive heart failure (CHF) is closely linked to a specific form of CSA called Cheyne-Stokes breathing. In this condition, impaired cardiac function affects blood flow and oxygen delivery, which in turn influences how the brain detects oxygen and carbon dioxide levels. The neurological changes induced by heart failure impair the brainstem’s ventilatory control, which causes a pathological breathing pattern that alternates between hyperventilation and apnea.

Neurodegenerative Diseases

Neurodegenerative disorders such as Parkinson’s disease, multiple system atrophy, and certain forms of dementia can contribute to CSA by affecting the brainstem and other regions involved in autonomic and respiratory control. These conditions progressively damage neural pathways that are essential for respiration. This means patients with neurodegenerative diseases often experience disturbances in breathing during sleep, which manifest as central apneas.

Connections to Other Health Issues

CSA is more than just a sleep disorder; it is deeply connected to other serious health conditions, particularly cardiovascular and neurological diseases. Interruptions in breathing and repeated pauses in respiration can cause hypoxia and increased sympathetic nervous system activity, which can cause stroke and heart failure. 

Patients experience a range of sleep apnea symptoms and neurological symptoms. It can be difficult to distinguish between the two disorders, but it is very important to diagnose the cause of the symptoms so that patients can receive timely intervention and correct treatment. 

Untreated CSA can impact brain function, leading to cognitive impairment, mood disorders, and persistent daytime fatigue. Recognizing these links highlights how CSA can cause broader systemic health challenges, making its diagnosis and management essential for improving overall patient outcomes.

Implications for Treatment and Management

CSA is caused by neurological dysfunction, which affects breathing control. It is important to have an individually tailored treatment plan that addresses both the apnea itself and its underlying causes. Positive airway pressure (PAP) therapies, such as CPAP, BiPAP, and adaptive servo ventilation (ASV) are effective in the management of CSA, helping to stabilize breathing and enhance oxygenation during sleep.

Underlying health conditions, for example, heart failure and other neurological disorders, have to be addressed at the same time. Fortunately, new developments such as phrenic nerve stimulation are becoming available for more complex cases. 

Advancing Research

Continued research into the causes of CSA is essential for improving diagnostics and developing more effective therapies. Currently, research is being carried out to understand brainstem function, chemoreceptor pathways, and the influence of neurological diseases on breathing and respiration.

Advances in neuroimaging and neurophysiology show the complexity of CSA mechanisms. Clinical trials are being carried out to help understand the disorder better, find innovative treatments, and combinations of therapies to help combat the illness. As our understanding deepens, it holds the potential to improve the health and well being of patients affected by CSA and reduce the risks that it poses.

Talk to your healthcare provider

Central sleep apnea (CSA) is a neurological disorder where the brain is unable to regulate breathing during sleep. This can be due to brainstem damage, heart failure, or neurodegenerative diseases. It is a neurological disorder and is linked to conditions that impair brain function. Recognizing the neurological causes of CSA is vital, as the condition can significantly affect overall health, including heart and brain function.

If you experience symptoms such as periodic breathing or pauses in breathing during sleep, it is important to speak to your healthcare provider as soon as possible. Early diagnosis and personalized treatment are essential for managing this complex condition, enhancing your quality of life and minimizing potential complications.