Abstract
STUDY OBJECTIVES: Catathrenia has been classified as a sleep-related breathing disorder variant in the third edition of the International Classification of Sleep Disorders, but its validity remains unverified. We analyzed the clinical descriptive variables and polysomnographic findings of catathrenia and discussed the similarities to and differences from those of obstructive sleep apnea, non-rapid eye movement parasomnias, and sleep bruxism (SB). METHODS: A retrospective analysis was conducted on 47 patients diagnosed with nocturnal groaning through polysomnography. We examined sex, body mass index, age at symptom onset, weekly symptom frequency, and presence/absence of comorbidities, including obstructive sleep apnea, periodic limb movement disorder, non-rapid eye movement parasomnia, and SB. The groaning event index was calculated according to sleep position and sleep stage. RESULTS: The distribution of patients with catathrenia did not show sex differences (male/female = 20:27), body mass index was 20.6 ± 3.0 kg/m(2), and age of onset was 18.2 ± 7.4 years. The groaning event index was higher in stages N1 and R than in stage N3 and in the supine position than in the lateral position. There were no cases complicated with non-rapid eye movement parasomnia, but the complication of SB was observed in 30% of the participants, and SB events appeared immediately before or during the interictal period of the groaning event episodes in these cases. CONCLUSIONS: Given the clinical background, posture- and sleep stage-dependent appearance of groaning events, and the relatively high complication rate of SB, catathrenia pathogenesis may be heterogeneous or comprise elements of different sleep disorders. CITATION: Takei Y, Nakayama H, Inoue Y. Characteristics of clinical descriptive variables and polysomnographic findings of catathrenia. J Clin Sleep Med. 2025;21(2):377-381.