Bringing light to the sirens of night: laryngoscopy in catathrenia during sleep.

Catathrenia is a rare sleep disorder characterised by groaning and prolonged expiration confined to sleep alternating with normal breathing that may occur at all sleep stages. After its first description in 1983 [1], catathrenia was recently introduced into the International Classification of Sleep Disorders [2]. Although the exact pathogenesis remains unknown, catathrenia has been considered a parasomnia. Important differential diagnoses include moaning during epileptic seizures, central sleep apnoea, sleep-related laryngospasm, expiratory snoring and stridor. Most patients complain about social distress in their partnership, and only a minority suffers from excessive daytime sleepiness (EDS). Continuous positive airway pressure (CPAP) treatment has shown to be effective in some patients [3].