WS1-3. Attended video–audio polysomnographic study about patients with catathrenia (sleep related groaning)

Sleep related groaning (catathrenia), which is characterized by episodes of monotonous vocalization during sleep, has been integrated in the International Classification of Sleep Disorders 2nd edition as a new parasomnia. This condition should be differentiated from moaning during epileptic seizures, central sleep apnea, sleep-related laryngospasm, snoring, and stridor. Attended video-polysomnography (PSG) with audio recording is necessary to make a diagnosis of catathrenia. As plysomnographic pattern of catathrenia closely resembles that of central sleep apnea, catathrenia can be easily scored erroneously or mistakenly recognized as central sleep apnea when polysomnogram alone is available. In catathrenia, a breath before an apnea is large inhalation, and associated activity in the snoring channel indicates a groaning noise. Since exhalation is prolonged, the patient’s breathing rate slows down during the episode. However, no oxygen desaturation occurs despite slower breathing rate. Catathrenia occurs both NREM and REM sleep depending on individuals. A few reports suggest that arousal mechanism plays an important role in triggering groaning, and some groups have proposed that catathrenia should be classified as sleep disordered breathing. Catathrenia can occur concomitantly with sleep bruxism and obstructive sleep apnea. In conclusion, detailed analysis of PSG data with video–audio recording is important to clarify the pathophysiology of catathrenia.