Catathrenia

Catathrenia is a rapid eye movement sleep parasomnia consisting of end-inspiratory apnea (breath holding) and expiratory groaning during sleep. Catathrenia is distinct from both somniloquy and obstructive sleep apnea. The sound is produced during exhalation as opposed to snoring which occurs during inhalation. It is usually not noticed by the person producing the sound but can be extremely disturbing to sleep partners, although once aware of it, sufferers tend to be woken up by their own groaning as well. Bed partners generally report hearing the person take a deep breath, hold it, then slowly exhale; often with a high-pitched squeak or groaning sound.

Catathrenia typically occurs during REM sleep, although it may also occur to a lesser degree during NREM sleep. Often the groaning occurs toward the end of the sleep cycle, within a couple hours of waking. In many cases it occurs exclusively during REM sleep. Catathrenia begins with a deep inspiration. The sufferer holds his breath against a closed glottis, similar to the Valsalva maneuver. After a period of time and some blood oxygen desaturation, there is an arousal, followed by expiration. Expiration can be slow and accompanied by sound caused by vibration of the vocal cords or a simple rapid exhalation with no sound.

There is a debate about whether the cause is physical or neurological, a question that requires further study. While some speculate about a direct correlation to high stress or the concept that this purely psychological, there is only anecdotal evidence of either cause.

Catathrenia has been defined as a parasomnia in the International Classification of Sleep Disorders Diagnostic and Coding Manual (ICSD-2), but there is debate about its classification.

A study in the SLEEP Journal by Guilleminault C; Hagen CC; Khaja AM. Catathrenia: "para-somnia or uncommon feature of sleep disordered breathing?". SLEEP 2008;31(1):132–139 concluded:

"Catathrenia may have subtypes related to sleep stage specificity or presence of sleep disordered breathing." and "CPAP and select soft tissue surgeries of the upper airway (often augmented with an oral appliance) successfully treated nocturnal groaning."

While a CPAP machine successfully treats catathrenia as defined by Dr. Guilleminault, there is debate whether he has confused catathrenia with expiratory snoring. Expiratory snoring can be cured by CPAP. It does not, however, include catathrenia's characteristic breath holding spells. Furthermore, there are catathrenia sufferers who have not seen improvement with CPAP, upper airway surgery, or oral appliance.

There are a few other similarities amongst catathrenia sufferers that have not yet been studied properly: Many took part in sports activities during teens and twenties which required breath-holding. They find a certain level of comfort in breath-holding, and often do it while awake. Sufferers themselves do not feel like they are experiencing a sleep apnea; the breath-holding appears controlled though unconscious. Oxygen desaturation during a catathrenia episode is usually negligible.

Because catathrenia is not considered life-threatening, there has been very little research done in the medical community, and many experts assume that the way to treat catathrenia is to treat the underlying sleep apnea, though there is no conclusive evidence published that catathrenia results from sleep apnea, and sleep studies show that not all sufferers of catathrenia have been diagnosed with sleep apnea.

While doctors tend to dismiss it as an inconvenience, sufferers routinely describe the condition's highly negative effects on their relationships, social lives and sleep quality.