title: Etiology of single-sided deafness and asymmetrical hearing loss.
abstract: CONCLUSIONS
  The present study revealed that various etiologies are involved in single-sided deafness (SSD), and that the cause of SSD and asymmetrical hearing loss (AHL) differed greatly between congenital/early-onset cases and adult cases. Clarification of the etiology is the first step toward providing appropriate intervention.
  
  
  OBJECTIVE
  The study aimed to clarify the etiology of SSD and AHL patients.
  
  
  METHODS
  The etiology of a total of 527 SSD or AHL patients who visited Shinshu University Hospital between 2006 and 2016 were analyzed by imaging as well as serological tests for mumps virus, and CMV DNA testing.
  
  
  RESULTS
  In our cohort of congenital/early-onset SSD (n = 210), the most prevalent cause in children was cochlear nerve deficiency (43.7%; 87 of 199 patients undergoing CT and/or MRI), followed by CMV infection, mumps infection, anomalies of the inner ear, ANSD, and other rare etiologies. In contrast, half of the adult SSD patients presented with idiopathic sensorineural hearing loss, followed by various types of otitis media, cerebellopontine angle tumor and other rare etiologies.
authors.affiliation: a Department of Otorhinolaryngology , Shinshu University School of Medicine , Nagano , Japan.|b Department of Hearing Implant Sciences , Shinshu University School of Medicine , Nagano , Japan.
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Usami
authors.affiliation: a Department of Otorhinolaryngology , Shinshu University School of Medicine , Nagano , Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kitoh
authors.affiliation: a Department of Otorhinolaryngology , Shinshu University School of Medicine , Nagano , Japan.|b Department of Hearing Implant Sciences , Shinshu University School of Medicine , Nagano , Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Moteki
authors.affiliation: a Department of Otorhinolaryngology , Shinshu University School of Medicine , Nagano , Japan.|b Department of Hearing Implant Sciences , Shinshu University School of Medicine , Nagano , Japan.
authors.forename: Shin-Ya
authors.initials: SY
authors.lastname: Nishio
authors.affiliation: a Department of Otorhinolaryngology , Shinshu University School of Medicine , Nagano , Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kitano
authors.affiliation: a Department of Otorhinolaryngology , Shinshu University School of Medicine , Nagano , Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: a Department of Otorhinolaryngology , Shinshu University School of Medicine , Nagano , Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Shinagawa
authors.affiliation: a Department of Otorhinolaryngology , Shinshu University School of Medicine , Nagano , Japan.
authors.forename: Yoh
authors.initials: Y
authors.lastname: Yokota
authors.affiliation: a Department of Otorhinolaryngology , Shinshu University School of Medicine , Nagano , Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Sugiyama
authors.affiliation: a Department of Otorhinolaryngology , Shinshu University School of Medicine , Nagano , Japan.
authors.forename: Kizuki
authors.initials: K
authors.lastname: Watanabe
mesh_terms: D000328:Adult; D002648:Child; D004279:DNA, Viral / Q000097:blood*; D046088:Hearing Loss, Unilateral / Q000097:blood / Q000000981:diagnostic imaging / Q000209:etiology*; D006801:Humans
chemical_list: D004279:DNA, Viral
keywords: Single-sided deafness; asymmetrical hearing loss; auditory neuropathy spectrum disorder; cochlear implant; cochlear nerve deficiency; cytomegalovirus; idiopathic sensorineural hearing loss; inner ear anomaly; mumps