title: Speech perception after cochlear implantation over a 4-year time period.
abstract: OBJECTIVE
  To evaluate the long-term speech perception of cochlear implantees and to compare the developing auditory performance patterns of prelingual children and postlingual deaf adults.
  
  
  METHODS
  Twenty-nine prelingually deaf children and 17 postlingually deaf adults who had been followed up for 4 years were included in the study. Speech perception ability was assessed by means of vowel and consonant confusion tests and the Korean version of the Central Institute of Deafness (K-CID) test (performed without visual cues). The test results were analyzed at 3 and 6 months after implantation and then annually.
  
  
  RESULTS
  In the prelingually deaf children, the average results continuously improved over the 4-year period. In the postlingually deaf adults, the average results did not improve further after the first 2 years. Individuals with < 5 years of deafness had a faster rate of recovery of speech perception than those who had been deaf for > 5 years. The K-CID scores were negatively correlated with age at implantation for the prelingually deaf group and with the duration of deafness in the postlingually deaf group. Children fitted with implants at a younger age showed better speech perception ability than those fitted with implants at an older age. Interestingly, prelingually deaf children aged 5-7 years at implantation showed the widest variation in individual outcomes. Amongst this group of children with highly variable outcomes, the metabolic status of brain cortices determined by means of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was available for three patients. The individual with the widest hypometabolic area had the best speech perception ability.
  
  
  CONCLUSIONS
  The extent of hypometabolism as assessed by FDG-PET seemed to be one of the major factors predicting the outcome of cochlear implantation.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul, South Korea.
authors.forename: Seung-Ha
authors.initials: SH
authors.lastname: Oh
authors.forename: Chong-Sun
authors.initials: CS
authors.lastname: Kim
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Kang
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
authors.forename: Hyo Jeong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Sun O
authors.initials: SO
authors.lastname: Chang
authors.forename: Soon-Hyun
authors.initials: SH
authors.lastname: Ahn
authors.forename: Chan Ho
authors.initials: CH
authors.lastname: Hwang
authors.forename: Hong Ju
authors.initials: HJ
authors.lastname: Park
authors.forename: Ja Won
authors.initials: JW
authors.lastname: Koo
mesh_terms: D000328:Adult; D000367:Age Factors; D001302:Audiometry, Speech / Q000379:methods; D001307:Auditory Perception / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D019929:Cochlear Implantation / Q000379:methods; D003054:Cochlear Implants; D015331:Cohort Studies; D003638:Deafness / Q000175:diagnosis / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007804:Language Development; D008137:Longitudinal Studies; D008297:Male; D017060:Patient Satisfaction; D011336:Probability; D012307:Risk Factors; D013063:Speech Discrimination Tests; D013065:Speech Intelligibility; D013067:Speech Perception / Q000502:physiology*; D013069:Speech Reception Threshold Test; D013997:Time Factors; D016896:Treatment Outcome