title: Frequency discrimination in ears with and without contralateral cochlear dead regions.
abstract: OBJECTIVE
  The purpose of this study was to test the ability to discriminate low-frequency pure-tone stimuli for ears with and without contralateral dead regions, in subjects with bilateral high-frequency hearing loss; we examined associations between hearing loss characteristics and frequency discrimination of low-frequency stimuli in subjects with high-frequency hearing loss.
  
  
  METHODS
  Cochlear dead regions were diagnosed using the TEN-HL test. A frequency discrimination test utilizing an adaptive three-alternative forced choice method provided difference limens for reference frequencies 0.25 kHz and 0.5 kHz.
  
  
  METHODS
  Among 105 subjects with bilateral high-frequency hearing loss, unilateral dead regions were found in 15 subjects. These, and an additional 15 matched control subjects without dead regions, were included in the study.
  
  
  RESULTS
  Ears with dead regions performed best at the frequency discrimination test. Ears with a contralateral dead region performed significantly better than ears without a contralateral dead region at 0.5 kHz, the reference frequency closest to the mean audiogram cut-off, while the opposite result was obtained at 0.25 kHz.
  
  
  CONCLUSIONS
  Results may be seen as sign of a contralateral effect of unilateral dead regions on the discrimination of stimuli with frequencies well below the audiogram cut-off in adult subjects with bilateral high-frequency hearing loss.
authors.affiliation: Department of Audiology, Haukeland University Hospital, Bergen, Norway. pederheggdal@gmail.com
authors.forename: Peder O Laugen
authors.initials: PO
authors.lastname: Heggdal
authors.forename: Ola
authors.initials: O
authors.lastname: Lind
authors.forename: K Jonas
authors.initials: KJ
authors.lastname: Brännström
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone; D001306:Auditory Pathways / Q000473:pathology / Q000503:physiopathology; D001309:Auditory Threshold; D016022:Case-Control Studies; D003051:Cochlea / Q000473:pathology / Q000503:physiopathology*; D006312:Hearing Loss, Bilateral / Q000473:pathology / Q000503:physiopathology / Q000523:psychology*; D006316:Hearing Loss, High-Frequency / Q000473:pathology / Q000503:physiopathology / Q000523:psychology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019986:Persons with Hearing Disabilities / Q000523:psychology*; D010897:Pitch Discrimination; D011571:Psychoacoustics; D021641:Recognition, Psychology; D055815:Young Adult