Expiration can be slow and accompanied by sound caused by vibration of the vocal cords or a simple rapid exhalation.

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.

The main characteristics are: There are a few other similarities[citation needed] amongst people with catathrenia that have not yet been studied properly: Certain side effects include sore throat, fatigue, and dizziness.

[8] Catathrenia must be distinguished from moaning during epileptic seizures, central sleep apnea, sleep-related laryngospasm, snoring, and stridor.

[citation needed] Some evidence indicates that continuous positive airway pressure can be an effective treatment for catathrenia:[22][23] in a study, the subject using CPAP significantly decreased the sounds typically produced because of the disorder, which almost disappeared.

Multiple studies have described nocturnal vocalisation among animals and have also reported some cases in humans, especially in patients with Parkinson's disease.