title: Mandarin Tone Identification in Cochlear Implant Users Using Exaggerated Pitch Contours.
abstract: OBJECTIVE
  To determine whether exaggerating the variations in fundamental frequency (F0) contours of Mandarin-based pitch fluctuations could improve tone identification by cochlear implant (CI) users.
  
  
  METHODS
  Twelve normal-hearing (NH) listeners and 11 CI users were tested for their ability to recognize F0 contours modeled after Mandarin tones, in 4- or 5-alternatives forced-choice paradigms. Two types of stimuli were used: computer-generated complex tones and voice recordings. Four contours were tested with voice recordings: flat, rise, fall, and dip. A fifth contour, peak, was added for complex tones. The F0 range of each contour was varied in an adaptive manner. A maximum-likelihood technique was used to fit a psychometric function to the performance data and extract threshold at 70% accuracy.
  
  
  RESULTS
  As F0 range increased, performance in tone identification improved but did not reach 100% for some CI users, suggesting that confusions between contours could always be made even with extremely exaggerated contours. Compared with NH participants, CI users required substantially larger F0 ranges to identify tones, on the order of 9.3 versus 0.4 semitones. CI users achieved better performance for complex tones than for voice recordings, whereas the reverse was true for NH participants. Confusion matrices showed that the "flat" tone was often a default option when the tone contour's F0 range presented was too narrow for participants to respond correctly.
  
  
  CONCLUSIONS
  These results demonstrate markedly impaired ability for CI users to identify tonal contours, but suggest that the use of exaggerated pitch contours may be helpful for tonal language perception.
authors.affiliation: *Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland †Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco School of Medicine, San Francisco, California.
authors.forename: Alice
authors.initials: A
authors.lastname: He
authors.forename: Mickael L
authors.initials: ML
authors.lastname: Deroche
authors.forename: Judy
authors.initials: J
authors.lastname: Doong
authors.forename: Patpong
authors.initials: P
authors.lastname: Jiradejvong
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Limb
mesh_terms: D000328:Adult; D000368:Aged; D019929:Cochlear Implantation; D003054:Cochlear Implants; D003638:Deafness / Q000503:physiopathology* / Q000534:rehabilitation; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D010898:Pitch Perception / Q000502:physiology*