Catathrenia, also known as nocturnal groaning, is a distinct sleep-related breathing disorder characterized by groaning or moaning sounds during exhalation while asleep. While often unnoticed by the individual, it can be disruptive to bed partners. It is a relatively rare phenomenon, though its true prevalence might be underestimated due to lack of awareness and misdiagnosis.
Understanding Catathrenia
Catathrenia is primarily an expiratory phenomenon, meaning the groaning sound occurs during exhalation. This distinguishes it from snoring (inhalation) or sleep apnea (breathing pauses). The groans can be monotonous, irregular, and vary in duration, sometimes lasting from a few seconds up to 40 seconds. These sounds are thought to originate from the larynx, or voice box, due to partial closure of the vocal cords during exhalation.
Individuals are often unaware they are making these sounds; bed partners or family members usually notice the nocturnal groaning first. While it can occur during both REM (rapid eye movement) and non-REM sleep, catathrenia is frequently observed during REM sleep, the stage associated with dreaming. Catathrenia is not typically associated with oxygen desaturation, meaning blood oxygen levels usually remain stable.
Factors Contributing to Catathrenia
The precise cause of catathrenia remains unclear, though several physiological components and associations have been proposed. Research suggests a possible link to malfunctioning nerve cells in the brain’s respiratory center, specifically the medulla oblongata, which might lead to prolonged exhalation. The involvement of the vagus nerve, which regulates breathing and vocalization, is also considered, contributing to the unique sounds.
Anatomical variations in the upper airway may also play a role. Associations include a narrow upper airway, a large tongue, or a small jaw. Sleep position can sometimes influence the occurrence or intensity of groaning, with some reporting more frequent or louder episodes when sleeping on their back. While distinct, catathrenia can coexist with obstructive sleep apnea, though their underlying mechanisms and treatments differ.
Approaches to Managing Catathrenia
Managing catathrenia often begins with lifestyle adjustments aimed at promoting better sleep. Establishing a consistent sleep schedule and creating a comfortable sleep environment can enhance overall sleep hygiene. Avoiding alcohol and sedatives before bedtime is important, as these substances can relax airway muscles and potentially exacerbate groaning. Experimenting with different sleep positions, such as side sleeping, may also help reduce the frequency or intensity of episodes.
For persistent cases, medical interventions overseen by a sleep specialist are available. Continuous Positive Airway Pressure (CPAP) therapy is a common and effective treatment, delivering a continuous stream of air to keep airways open and prevent groaning. Oral appliances, custom-fitted by a dentist, are another option; these devices reposition the jaw and tongue to maintain an open airway. In rare instances, surgical interventions may be considered if a specific anatomical issue is identified.
When to Seek Professional Guidance
Consulting a healthcare professional, especially a sleep specialist, becomes important when catathrenia persists despite lifestyle adjustments or significantly impacts sleep quality for the individual or a bed partner. If nocturnal groaning leads to concerns about underlying sleep apnea or other sleep disorders, a professional evaluation is warranted. Individuals experiencing daytime fatigue, unrefreshing sleep, or a decline in daytime alertness should also seek medical advice. A proper diagnosis often involves an overnight sleep study, known as polysomnography, which can help differentiate catathrenia from other conditions and guide treatment.