Catathrenia, sometimes referred to as nocturnal groaning, is a distinct sleep phenomenon often mistaken for snoring or sleep talking. The medical term for this specific sleep-related noise is Catathrenia. It is an involuntary vocalization that sounds like a sustained whine, groan, or moan.
What Exactly is Catathrenia?
Catathrenia is a relatively rare sleep-related breathing disorder characterized by a loud, often monotonic sound during sleep. The noise is typically a prolonged moan, groan, or humming sound lasting anywhere from a few seconds up to nearly a minute. This sound is distinct from snoring because it is produced exclusively during the exhalation phase of breathing, rather than inhalation.
It is also set apart from sleep talking, as the vocalization is usually a simple, repetitive sound without recognizable words. Individuals are almost always oblivious to the noise, often learning about the condition from an alarmed bed partner. Although classified as a parasomnia, its connection to a specific breathing pattern gives it a unique classification.
The Underlying Mechanism of Sleep Moaning
Catathrenia is fundamentally a respiratory event involving a specific sequence of breathing mechanics. The episode begins with a deep, slow breath, followed by a brief period of breath-holding. The characteristic moaning sound is created when air is slowly released during a prolonged exhalation against a partially closed airway. The sound originates in the larynx, or voice box, where the vocal cords restrict the airflow. This partial closure, termed laryngeal adduction, causes the vocal cords to vibrate as the air is pushed out, generating the sustained groan. The sound is the result of a pressurized, slow release of air through a narrowed opening.
This unique breathing pattern often occurs when muscle tone is reduced during non-REM sleep, but it can also occur during REM sleep. Researchers suspect the origin may be related to an abnormality in the brain’s respiratory control center. The condition is also sometimes linked to subtle structural factors, such as a narrow upper airway, that may predispose an individual to airway restriction during sleep.
Diagnosis and Associated Health Impacts
The definitive diagnosis of catathrenia requires an overnight sleep study, known as Polysomnography, performed in a specialized sleep center. During this study, technicians monitor biological functions, including airflow, brain waves, and heart rate. The polysomnogram records the unique breathing pattern—the deep inhalation followed by the prolonged, moaning exhalation—and confirms the sounds originate from the larynx. The sleep study also rules out more common conditions, such as snoring or obstructive sleep apnea (OSA), which involves complete breathing pauses. Unlike other parasomnias, catathrenia is not associated with complex brain wave patterns or movements indicative of an arousal. The lack of significant oxygen desaturation helps differentiate it from serious breathing disorders.
Catathrenia is generally considered a benign condition that does not pose a physical health risk. While the groaning rarely wakes the individual, it can sometimes lead to unrefreshing sleep or mild daytime fatigue. The most significant impact is social, often causing distress and embarrassment for the person affected. The loud, unusual nature of the sound is a major disruptor for any bed partner, frequently leading to relationship strain and social avoidance.
Management and Treatment Options
Management focuses on reducing or eliminating the nocturnal groaning, as catathrenia primarily affects the quality of life and the sleep of others. The most effective treatment is Continuous Positive Airway Pressure (CPAP) therapy. A CPAP machine delivers a steady stream of pressurized air through a mask, keeping the upper airway open. This pressure stabilizes the airway and prevents the laryngeal adduction—the partial closing of the vocal cords—that causes the sound. CPAP successfully eliminates the groaning sound for many individuals and can also improve general sleep quality.
Another nonsurgical option involves custom-fitted oral appliances, designed to keep the jaw and tongue positioned forward to maintain an open airway. In rare cases where nonsurgical treatments are ineffective, an ear, nose, and throat specialist may consider surgical interventions. Procedures such as tonsillectomy may reduce the groaning, particularly if underlying airway obstructions exist. A diagnosis confirmed by a sleep specialist is necessary to determine the most appropriate course of action, which may also include counseling to address the anxiety and social embarrassment caused by the condition.