Hearing unusual sounds, such as deep moaning or groaning, coming from a sleeping person can be unsettling for those nearby. These nocturnal vocalizations may cause worry about the sleeper’s health or sleep quality. Although the sounds are loud enough to disturb a bed partner, the individual making them is typically unaware of the noise. Understanding this phenomenon provides reassurance that it is often a benign condition.
What is Catathrenia?
The medical term for this nighttime groaning is Catathrenia, a rare sleep-related breathing disorder. It is characterized by repeated episodes of a drawn-out, often monotone sound occurring during a prolonged exhalation. The noise is created when a person takes a deep breath, holds it briefly, and then slowly releases the air against a partially closed vocal cord structure in the larynx.
This exhalatory groan can last from a few seconds up to nearly a minute and may be repeated in clusters throughout the night. Catathrenia frequently occurs during Rapid Eye Movement (REM) sleep. Though the sound can reach decibel levels similar to loud talking, the sleeper rarely wakes up or remembers the episode. The primary impact of the disorder is almost exclusively on the sleep quality of the bed partner.
Distinguishing Catathrenia from Other Sleep Sounds
Catathrenia must be differentiated from more common sleep disturbances like snoring and Obstructive Sleep Apnea (OSA). Snoring is produced by the vibration of soft tissues in the throat and occurs during inhalation. Conversely, the noise in Catathrenia originates from the voice box and is specifically produced during exhalation.
Differentiating Catathrenia from OSA is significant because the two conditions have very different health implications. Obstructive Sleep Apnea involves breathing pauses that cause drops in blood oxygen levels and carry severe health risks. Catathrenia, while involving an abnormal breathing pattern, is not associated with oxygen desaturation or a compromised airway. It is generally considered a benign condition that presents a social issue rather than a serious medical threat.
Causes and Associated Factors
The precise cause of Catathrenia is largely unknown and is often considered idiopathic, meaning it arises spontaneously. Current theories suggest the groaning may be related to an abnormality in the respiratory control center of the brain during sleep. The mechanism involves a forced, prolonged expulsion of air to overcome resistance in the airway, possibly due to a partial closure of the glottis.
Structural factors in the upper airway may also play a role. Individuals with Catathrenia may have craniofacial characteristics such as a small jaw or a narrow upper airway. This anatomical structure could contribute to the difficulty in breathing out, leading to the characteristic groaning sound. The condition has also been associated with a personal or family history of other parasomnias, such as sleepwalking or sleep talking.
Treatment and Management
Since Catathrenia is primarily a nuisance for the partner rather than a health risk for the sleeper, management strategies aim to reduce the noise. The most effective medical treatment is often Continuous Positive Airway Pressure (CPAP) therapy. The pressurized air delivered by the CPAP machine helps stabilize the airway and maintain an open glottis during exhalation, often resolving the groaning completely.
Another intervention involves using an oral appliance, a custom-fitted dental device designed to reposition the lower jaw and tongue forward. This adjustment helps enlarge the upper airway space and reduce the respiratory effort that causes the moaning sound. For a definitive diagnosis and to rule out other sleep disorders like Obstructive Sleep Apnea, a consultation with a sleep specialist is recommended. They will often prescribe a polysomnography, or overnight sleep study, which includes audio-video recording to confirm the nature of the vocalizations.