title: Impact of cochlear nerve deficiency determined using 3-dimensional magnetic resonance imaging on hearing outcome in children with cochlear implants.
abstract: OBJECTIVE
  1) To review the radiologic and audiologic data of 656 children with sensorineural hearing impairment who underwent 3-dimensional magnetic resonance imaging (MRI) in our cochlear implant (CI) center to understand the incidence of cochlear nerve deficiency (CND); and 2) to compare postimplant auditory and speech intelligibility outcomes in implantees with cochlear nerve (CN) aplasia, CN hypoplasia, and normal CN.
  
  
  METHODS
  A retrospective cohort study.
  
  
  METHODS
  A tertiary medical center.
  
  
  METHODS
  A total of 656 patients (aged 0-18 yr; mean, 4.5 ± 4.3 yr) who underwent MRI in our center during May 2000 to December 2012.
  
  
  METHODS
  The radiologic/audiologic data were reviewed. The postimplant outcomes of 13 implantees with CND (7 aplasia and 6 hypoplasia) were compared with 50 non-CND implantees using the Categories of Auditory Performance (CAP) and the Speech Intelligibility Rating (SIR) scales.
  
  
  RESULTS
  Upon MRI, 139 patients (21.2%) exhibited CND. Bilateral CN aplasia occurred in 4.3% of the patients with severe-to-profound deafness (588 cases) and in one-fifth of patients with CND. The aplasia group showed significantly worse postimplant CAP (p = 0.002) and SIR (p = 0.009) scores than the non-CND group. No significant difference was noted between the hypoplasia group and the non-CND group.
  
  
  CONCLUSIONS
  Although the audiologic and radiologic results may be incompatible, the majority of patients with CND may be well delineated preoperatively using MRI. The type of CND (aplasia/hypoplasia) may affect CI outcomes. Patients implanted on the side with CN hypoplasia are more likely to exhibit favorable results compared with patients implanted on the side with CN aplasia.
authors.affiliation: *Department of Otolaryngology, Chang-Gung Memorial Hospital, College of Medicine, †Molecular Imaging Center and Departments of Diagnostic Radiology and Medical Imaging, and ‡Radiological Sciences, Chang-Gung University, Linkou, Taiwan, Republic of China.
authors.forename: Che-Ming
authors.initials: CM
authors.lastname: Wu
authors.forename: Li-Ang
authors.initials: LA
authors.lastname: Lee
authors.forename: Chin-Kuo
authors.initials: CK
authors.lastname: Chen
authors.forename: Kai-Chieh
authors.initials: KC
authors.lastname: Chan
authors.forename: Yung-Ting
authors.initials: YT
authors.lastname: Tsou
authors.forename: Shu-Hang
authors.initials: SH
authors.lastname: Ng
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D019929:Cochlear Implantation / Q000379:methods*; D003054:Cochlear Implants; D003056:Cochlear Nerve / Q000002:abnormalities*; D015331:Cohort Studies; D005260:Female; D006309:Hearing; D006319:Hearing Loss, Sensorineural / Q000209:etiology* / Q000601:surgery*; D006320:Hearing Tests; D006801:Humans; D021621:Imaging, Three-Dimensional; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D012189:Retrospective Studies; D013065:Speech Intelligibility