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Purpose: Catathrenia is a rare sleeping disorder characterized by repetitive nocturnal groaning during prolonged expirations. Patients with catathrenia had heterogeneous polysomnographic, comorbidity, craniofacial characteristics, and responses to treatment. Identifying phenotypes of catathrenia might benefit the exploration of etiology and personalized therapy. Patients and Methods: Sixty-six patients diagnosed with catathrenia by full-night audio/video polysomnography seeking treatment with mandibular advancement devices (MAD) or continuous positive airway pressure (CPAP) were included in the cohort. Polysomnographic characteristics including sleep architecture, respiratory, groaning, and arousal events were analyzed. Three-dimensional (3D) and 2D craniofacial hard tissue and upper airway structures were evaluated with cone-beam computed tomography and lateral cephalometry. Phenotypes of catathrenia were identified by K-mean cluster analysis, and inter-group comparisons were assessed. Results: Two distinct clusters of catathrenia were identified: cluster 1 (n=17) was characterized to have more males (71%), a longer average duration of groaning events (18.5± 4.8 and 12.8± 5.7s, p =0.005), and broader upper airway (volume 41,386± 10,543 and 26,661± 6700 mm 3 , p < 0.001); cluster 2 (n=49) was characterized to have more females (73%), higher respiratory disturbance index (RDI) (median 1.0 0.3, 2.0 and 5.2 1.2, 13.3/h, p =0.009), more respiratory effort-related arousals (RERA)(1 1, 109 and 32 13, 57), p =0.005), smaller upper airway (cross-sectional area of velopharynx 512± 87 and 339± 84 mm 2 , p < 0.001) and better response to treatment (41.2% and 82.6%, p =0.004). Conclusion: Two distinct phenotypes were identified in patients with catathrenia, primary catathrenia, and catathrenia associated with upper airway obstruction, suggesting respiratory events and upper airway structures might be related to the etiology of catathrenia, with implications for its treatment. Keywords: subtype, groaning, upper airway, treatment, OSA, sleep-disordered breathing
Yu et al. (Wed,) studied this question.