title: Cochlear nerve deficiency and associated clinical features in patients with bilateral and unilateral hearing loss.
abstract: OBJECTIVE
  To clarify the prevalence and clinical characteristics of cochlear nerve deficiency (CND) in patients with congenital bilateral and unilateral hearing loss.
  
  
  METHODS
  Retrospective case review.
  
  
  METHODS
  Tertiary referral center.
  
  
  METHODS
  One hundred fourteen children with bilateral and 56 children with congenital unilateral sensoneural hearing loss.
  
  
  METHODS
  Review of medical records, audiologic tests, and imaging studies. Imaging studies were evaluated for the presence or absence of abnormalities in the bony cochlear nerve canal (BCNC), internal auditory canal (IAC), and inner ear.
  
  
  RESULTS
  The prevalence of CND, whether unilateral or bilateral, was much higher in the unilateral than in the bilateral hearing loss group: 50% (28/56) versus 5.3% (6/114). Among the 6 children with bilateral hearing loss and CND, 2 had bilateral BCNC stenosis alone, 2 had bilateral BCNC stenosis and unilateral IAC stenosis, 1 had unilateral BCNC stenosis alone, and 1 had unilateral IAC stenosis alone. All 28 children with unilateral hearing loss and CND had BCNC stenosis, whereas 9 (32.1%) also had concurrent IAC stenosis. Three of the 6 children with CND and bilateral hearing loss and 5 of the 28 children with CND and unilateral hearing loss also had other inner ear abnormalities.
  
  
  CONCLUSIONS
  Our results suggest differences in the causes and mechanisms of CND in children with bilateral versus unilateral hearing loss.
authors: Division of Otolaryngology, Chiba Children's Hospital, Chiba, Japan. a.nkn@pref.chiba.lg.jp
authors: Atsuko
authors: A
authors: Nakano
authors: Yukiko
authors: Y
authors: Arimoto
authors: Tatsuo
authors: T
authors: Matsunaga
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003056:Cochlear Nerve / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000503:physiopathology; D007758:Ear, Inner / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D006312:Hearing Loss, Bilateral / Q000151:congenital / Q000000981:diagnostic imaging* / Q000209:etiology; D006319:Hearing Loss, Sensorineural / Q000151:congenital / Q000000981:diagnostic imaging* / Q000209:etiology; D046088:Hearing Loss, Unilateral / Q000151:congenital / Q000000981:diagnostic imaging* / Q000209:etiology; D006801:Humans; D007223:Infant; D011859:Radiography; D012189:Retrospective Studies; D000160:Vestibulocochlear Nerve Diseases / Q000151:congenital / Q000000981:diagnostic imaging* / Q000209:etiology; D055815:Young Adult