title: Prevalence of various etiologies of hearing loss among cochlear implant recipients: Systematic review and meta-analysis.
abstract: OBJECTIVE
  To investigate the etiology of deafness in cochlear implanted children and to address the question whether there is a need for more thorough diagnostics, especially concerning genetics.
  
  
  METHODS
  Systematic review. Four databases were searched for studies (year 2000-2014) on cochlear implanted children (n > 100). Studies were excluded if etiology had influenced their inclusion criteria. Eligibility and methodological quality were assessed independently by three authors. The studies' description of diagnostic evaluation was categorized in three groups.
  
  
  METHODS
  Sixteen studies were included (5069 children).
  
  
  RESULTS
  The most common etiological categories were 'Unknown' 40.3% (95% CI 32.8 to 48.0), 'Non-syndromic' 22.4% (95% CI 17.1 to 28.2), and 'Postnatal' 11.3% (95% CI 7.2 to 16.2). Studies published after 2006 had a lower proportion of 'Unknown' etiology 35.3% (95% CI 28.0 to 42.8) than older 45.5% (95% CI 31.0 to 60.4). Important information was missing from several studies: 11 (69%) studies did not provide detailed description on diagnostic evaluation of the etiology of deafness and had a higher proportion of 'Unknown' etiology.
  
  
  CONCLUSIONS
  In order to ensure a higher level of comparability in future studies, we recommend agreement upon an international standard of diagnostics and the introduction of an international standard for reporting etiology.
authors.affiliation: a Department of Otorhinolaryngology , Aarhus University Hospital , Aarhus C , Denmark.
authors.forename: Niels Krintel
authors.initials: NK
authors.lastname: Petersen
authors.affiliation: a Department of Otorhinolaryngology , Aarhus University Hospital , Aarhus C , Denmark.
authors.forename: Anders W
authors.initials: AW
authors.lastname: Jørgensen
authors.affiliation: a Department of Otorhinolaryngology , Aarhus University Hospital , Aarhus C , Denmark.
authors.forename: Therese
authors.initials: T
authors.lastname: Ovesen
mesh_terms: D002648:Child; D002675:Child, Preschool; D019929:Cochlear Implantation; D003054:Cochlear Implants; D003638:Deafness / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D005260:Female; D005820:Genetic Testing / Q000592:standards; D006801:Humans; D008297:Male; D012015:Reference Standards; D063189:Symptom Assessment / Q000592:standards*
keywords: Cochlear implant; demographics/epidemiology; etiology; pediatric; syndromes/genetics