title: Risk factors for loss of ipsilateral residual hearing after hybrid cochlear implantation.
abstract: OBJECTIVE
  Residual low-frequency acoustic hearing benefits cochlear implantees in difficult listening situations such as understanding speech in noise and music appreciation. Most subjects retain functional residual hearing in the operated ear. A small number of patients, however, will lose significant ipsilateral residual hearing after short-electrode cochlear implantation. The objectives of this retrospective series are to determine whether predisposition to hearing loss after implantation exists in a subset of patients and to assess the functional impact of this hearing loss on clinical measures of combined electric and acoustic hearing.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  Multicenter clinical trial; tertiary care facility.
  
  
  METHODS
  Hearing preservation cochlear implant recipients.
  
  
  METHODS
  Frequency-averaged ipsilateral hearing loss at 1 year after activation.
  
  
  RESULTS
  Eighty-five patients from the Hybrid S8 FDA trial had serial postoperative audiometric measurements. Twenty-two of these patients, implanted at the home institution, provided additional medical data. Univariate analysis (Pearson's, Spearman's, Student's t test) showed that the severity of hearing loss at 1 year after activation was significantly correlated with age, male gender, and noise-induced hearing loss as the etiology of hearing impairment. A multivariate regression model corroborated these variables. No other medical factors were predictive. Clinical measures of speech perception (Consonant-Nucleus-Consonant and Hearing in Noise Test) worsened with hearing loss in ipsilateral but not bilateral listening conditions.
  
  
  CONCLUSIONS
  Age, male gender, and a history of noise-induced hearing loss correlate with the severity of hearing loss at 1 year after activation. Even the most severely affected patients benefit from bilateral electric and acoustic inputs.
authors: *Department of Otolaryngology-Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa; †Department of Otolaryngology Head and Neck Surgery, Oregon Health Science University, Portland, Oregon; and ‡Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, Iowa, U.S.A.
authors: Jonathan C
authors: JC
authors: Kopelovich
authors: Lina A J
authors: LA
authors: Reiss
authors: Jacob J
authors: JJ
authors: Oleson
authors: Emily S
authors: ES
authors: Lundt
authors: Bruce J
authors: BJ
authors: Gantz
authors: Marlan R
authors: MR
authors: Hansen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001307:Auditory Perception / Q000502:physiology; D019929:Cochlear Implantation / Q000009:adverse effects*; D003054:Cochlear Implants; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006309:Hearing; D034381:Hearing Loss / Q000453:epidemiology / Q000503:physiopathology* / Q000601:surgery*; D006320:Hearing Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013067:Speech Perception / Q000502:physiology; D055815:Young Adult