title: Cochlear implantation in a patient with profound hearing loss with the A1555G mitochondrial mutation.
abstract: OBJECTIVE
  This study aimed to describe the performance of a cochlear implant in a patient with profound hearing loss with the A1555G mitochondrial mutation.
  
  
  METHODS
  The study was conducted at two university hospitals.
  
  
  METHODS
  A 50-year-old Japanese man in whom bilateral profound hearing loss developed after administration of streptomycin at the age of 23 participated. The pedigree of the family showed exclusively maternal transmission of hearing impairment.
  
  
  METHODS
  Genetic study and auditory rehabilitation with a cochlear implant were performed.
  
  
  RESULTS
  The A1555G point mutation was identified from the patient's mitochondrial DNA. Since activation of the implant, the patient has been using it successfully with a monosyllable recognition score of 78% using Japanese word lists for speech audiometry.
  
  
  CONCLUSIONS
  The current case indicated that cochlear implantation may be a valuable choice of therapy for the patient with profound hearing loss with the A1555G mutation. The excellent auditory performance with a cochlear implant suggests that hearing loss associated with this mutation is primarily caused by insult to the cochlear tissue containing rich mitochondria (i.e., hair cells or stria vascularis or both), not to the cochlear nerve and its central connections.
authors.affiliation: Department of Otorhinolaryngology, Miyazaki Medical College, Kiyotake, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tono
authors.forename: Y
authors.initials: Y
authors.lastname: Ushisako
authors.forename: K
authors.initials: K
authors.lastname: Kiyomizu
authors.forename: S
authors.initials: S
authors.lastname: Usami
authors.forename: S
authors.initials: S
authors.lastname: Abe
authors.forename: H
authors.initials: H
authors.lastname: Shinkawa
authors.forename: S
authors.initials: S
authors.lastname: Komune
mesh_terms: D000904:Antibiotics, Antitubercular / Q000009:adverse effects*; D001302:Audiometry, Speech; D019929:Cochlear Implantation; D004272:DNA, Mitochondrial / Q000235:genetics*; D006319:Hearing Loss, Sensorineural / Q000139:chemically induced / Q000175:diagnosis / Q000235:genetics* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D017354:Point Mutation / Q000235:genetics*; D013307:Streptomycin / Q000009:adverse effects*
chemical_list: D000904:Antibiotics, Antitubercular; D004272:DNA, Mitochondrial; D013307:Streptomycin