title: Discrimination of Japanese monosyllables in patients with high-frequency hearing loss.
abstract: OBJECTIVE
  To analyze the difficulty of discriminating Japanese nonsense monosyllables in each of several grades of high-frequency hearing loss and to evaluate the limitations of amplification.
  
  
  METHODS
  We collected retrospective data on the discrimination of Japanese nonsense monosyllables by patients with three grades of high-frequency hearing loss who fulfilled or nearly fulfilled the Japanese criteria for EAS. Discrimination of the twenty monosyllables included in the 67-S speech audiometric test, which is approved by the Japan Audiological Society, was evaluated under quiet conditions.
  
  
  RESULTS
  One hundred and five ears of ninety-one adults with high-frequency hearing loss were tested. We classified the ears according to hearing threshold at 1000 Hz; Group 1: <45 dB; Group 2: ≥45 dB and <70 dB; Group 3: ≥70 dB. Under the best conditions, the best speech discrimination scores were 72.3 ± 18.6% (mean ± SD, N=11), 56.9 ± 19.9% (N=57) and 38.1 ± 22.6% (N=37) in Group 1, Group 2 and Group 3, respectively. For most of the monosyllables, discrimination score declined gradually as high-frequency hearing loss became more severe. The high incidence in the Japanese language of [k], an easy consonant to distinguish, may be an advantage for patients with high-frequency hearing loss who use hearing aids. By employing a new confusion matrix that displays consonants and the following vowels separately, we were able to reveal the interactions of those two components. We observed that discrimination of preceding nasal consonants and that of the following vowels were not independent in patients with high-frequency hearing loss.
  
  
  CONCLUSIONS
  Our classification based on threshold at 1000 Hz was useful to predict the effectiveness and limitations of amplification in high-frequency hearing loss. Threshold at 1000 Hz can be an index enabling us to refine the indications of EAS for native Japanese speakers to maximize its effectiveness against high-frequency hearing loss.
authors.affiliation: Department of Otolaryngology, University of Tokyo, Japan. Electronic address: karinos-tky@umin.ac.jp.
authors.forename: Shotaro
authors.initials: S
authors.lastname: Karino
authors.affiliation: Department of Otolaryngology, Shinshu University, Japan.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Usami
authors.affiliation: Department of Otolaryngology, Toranomon Hospital, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Kumakawa
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, Nagasaki University Graduate School of Biomedical Sciences, Japan.
authors.forename: Haruo
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Otolaryngology, Miyazaki University, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tono
authors.affiliation: Department of Otolaryngology, Kobe City Medical Center, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Naito
authors.affiliation: Department of Otolaryngology, Kinki University, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Doi
authors.affiliation: Department of Otolaryngology, Teikyo University, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Ito
authors.affiliation: Department of Otolaryngology, Sakura Medical Center, Toho University, Japan.
authors.forename: Mitsuya
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Speech, Language and Hearing Therapy, Mejiro University, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Sakata
authors.affiliation: Department of Otolaryngology, Shinshu University, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takumi
authors.affiliation: Department of Hearing Implant Science, Shinshu University, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iwasaki
authors.affiliation: Department of Otolaryngology, University of Tokyo, Japan.
authors.forename: Akinobu
authors.initials: A
authors.lastname: Kakigi
authors.affiliation: Department of Otolaryngology, University of Tokyo, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Yamasoba
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001302:Audiometry, Speech; D005260:Female; D006316:Hearing Loss, High-Frequency / Q000503:physiopathology*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013063:Speech Discrimination Tests; D013067:Speech Perception / Q000502:physiology*
keywords: Confusion matrix; Monosyllable; Speech discrimination