title: Functional magnetic resonance imaging of hearing-impaired children under sedation before cochlear implantation.
abstract: OBJECTIVE
  To investigate functional magnetic resonance imaging (fMRI) in pediatric cochlear implantation candidates with residual hearing who are under sedation for evaluation of auditory function.
  
  
  METHODS
  During fMRI, subjects heard a random sequence of tones (250-4000 Hz) presented 10 dB above hearing thresholds. Tones were interleaved with silence in a block-periodic fMRI design with 30-second on-off intervals. Twenty-four axial sections (5 mm thick) covering most of the brain were obtained every 3 seconds for a total acquisition time of 5.5 minutes.
  
  
  METHODS
  Single tertiary academic medical institution.
  
  
  METHODS
  Severely to profoundly hearing-impaired children (n=10; mean age, 49.1 months). During fMRI, subjects were awake (n=2) or sedated with pentobarbital sodium if their weight was 10 kg or greater (n=4) or chloral hydrate if their weight was less than 10 kg (n=4).
  
  
  METHODS
  Detection of brain activation by fMRI in the primary auditory cortex (A1) in hearing-impaired patients under sedation, and correlation of A1 activation with hearing levels measured after cochlear implantation.
  
  
  RESULTS
  In most subjects, fMRI detected significant levels of activation in the A1 region before cochlear implantation. The improvement in hearing threshold after cochlear implantation correlated strongly (linear regression coefficient, R=0.88) with the amount of activation in the A1 region detected by fMRI before cochlear implantation.
  
  
  CONCLUSIONS
  Functional MRI can be considered a means of assessing residual function in the A1 region in sedated hearing-impaired toddlers. With improvements in acquisition, processing, and sedation methods, fMRI may be translated into a prognostic indicator for outcome after cochlear implantation in infants.
authors.affiliation: Imaging Research Center, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH 45229-3039, USA.
authors.forename: Ankur M
authors.initials: AM
authors.lastname: Patel
authors.forename: Lisa D
authors.initials: LD
authors.lastname: Cahill
authors.forename: Jennifer
authors.initials: J
authors.lastname: Ret
authors.forename: Vincent
authors.initials: V
authors.lastname: Schmithorst
authors.forename: Daniel
authors.initials: D
authors.lastname: Choo
authors.forename: Scott
authors.initials: S
authors.lastname: Holland
mesh_terms: D000161:Acoustic Stimulation; D001301:Audiometry, Pure-Tone; D001303:Auditory Cortex / Q000473:pathology*; D001309:Auditory Threshold; D002675:Child, Preschool; D002697:Chloral Hydrate / Q000008:administration & dosage; D019929:Cochlear Implantation; D005072:Evoked Potentials, Auditory; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000601:surgery*; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D010424:Pentobarbital / Q000008:administration & dosage; D011184:Postoperative Period; D011300:Preoperative Care
chemical_list: D006993:Hypnotics and Sedatives; D002697:Chloral Hydrate; D010424:Pentobarbital