title: Anatomical characteristics of catathrenia (nocturnal groaning) in upper airway and orofacial structures.
abstract: BACKGROUND
  Catathrenia is a rare sleep disorder characterized by repeated groaning in a protracted expiration preceded by a deep inspiration. This study aimed to explore whether anatomy is one of pathophysiology of catathrenia by investigating the anatomical features associated with catathrenia in the upper airway, craniofacial structures, and dental patterns.
  
  
  METHODS
  Twenty-two patients with catathrenia (7 males, 15 females; age 22 to 69 years) were recruited as well as 66 patients matched by age and gender (matching proportion 1:3) with obstructive sleep apnea syndrome (OSAS). Both groups underwent cephalograms and dental casting, and cephalometric measurements and the Peer Assessment Rating (PAR) index was applied. Differences between the two groups were evaluated and cephalometric measurements in catathrenia group were compared with control values of Chinese patients from previous studies.
  
  
  RESULTS
  As for airway-related measurements, increased PNS-R, PNS-UPW, and H-FH and decreased SPT and TGL were found in catathrenia group compared to normal values. Such trends were found even more evident when compared with the OSAS Group. As for craniofacial parameters, values of U1/NA and U1/SN were found increased in the catathrenia group compared with normal values and values of MP/FH and Y decreased. The differences were more distinct from the OSAS Group. Increased arch lengths and upper inter-first molar widths, and decreased overbite and PAR index, were found in catathrenia group compared with the OSAS Group.
  
  
  CONCLUSIONS
  Catathrenia patients present with a broad upper airway, yet protrusive upper incisors and flat mandibular angles. Anatomical characteristics of catathrenia are different from those associated with OSAS, namely a wide airway, large skeleton, and good occlusion.
authors.affiliation: Department of Orthodontics, Peking University School and Hospital of Stomatology, 22 Zhongguancun South Avenue, Haidian District, Beijing, 100081, People's Republic of China.
authors.forename: Zeliang
authors.initials: Z
authors.lastname: Hao
authors.affiliation: PKU-Upenn Sleep Center, Peking University International Hospital, Beijing, 102206, People's Republic of China.
authors.forename: Liyue
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Orthodontics, Peking University School and Hospital of Stomatology, 22 Zhongguancun South Avenue, Haidian District, Beijing, 100081, People's Republic of China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Pulmonary Medicine, Aerospace Central Hospital, Beijing, 100049, People's Republic of China.
authors.forename: Xueli
authors.initials: X
authors.lastname: Lan
authors.affiliation: Department of Orthodontics, Peking University School and Hospital of Stomatology, 22 Zhongguancun South Avenue, Haidian District, Beijing, 100081, People's Republic of China. xmgao@263.net.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Pulmonary Medicine, Peking University People's Hospital, Beijing, 100044, People's Republic of China. hanfang1@hotmal.com.
authors.forename: Fang
authors.initials: F
authors.lastname: Han
mesh_terms: D000328:Adult; D000368:Aged; D002508:Cephalometry; D003735:Dental Casting Technique; D045853:Exhalation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000503:physiopathology; D008875:Middle Aged; D008963:Molar / Q000503:physiopathology; D057887:Overbite / Q000503:physiopathology; D010159:Palate / Q000503:physiopathology; D012016:Reference Values; D012135:Respiratory Sounds / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*; D012893:Sleep Wake Disorders / Q000503:physiopathology*; D055815:Young Adult
keywords: Catathrenia; Cephalometrics; Craniofacial; OSAS; Occlusion; Upper airway