title: Level discrimination of speech sounds by hearing-impaired individuals with and without hearing amplification.
abstract: OBJECTIVE
  The current study was designed to see how hearing-impaired individuals judge level differences between speech sounds with and without hearing amplification. It was hypothesized that hearing aid compression should adversely affect the user's ability to judge level differences.
  
  
  METHODS
  Thirty-eight hearing-impaired participants performed an adaptive tracking procedure to determine their level-discrimination thresholds for different word and sentence tokens, as well as speech-spectrum noise, with and without their hearing aids. Eight normal-hearing participants performed the same task for comparison.
  
  
  RESULTS
  Level discrimination for different word and sentence tokens was more difficult than the discrimination of stationary noises. Word level discrimination was significantly more difficult than sentence level discrimination. There were no significant differences, however, between mean performance with and without hearing aids and no correlations between performance and various hearing aid measurements.
  
  
  CONCLUSIONS
  There is a clear difficulty in judging the level differences between words or sentences relative to differences between broadband noises, but this difficulty was found for both hearing-impaired and normal-hearing individuals and had no relation to hearing aid compression measures. The lack of a clear adverse effect of hearing aid compression on level discrimination is suggested to be due to the low effective compression ratios of currently fit hearing aids.
authors.affiliation: MRC Institute of Hearing Research (Scottish Section), Glasgow Royal Infirmary, Glasgow, United Kingdom. bill@ihr.gla.ac.uk
authors.forename: William M
authors.initials: WM
authors.lastname: Whitmer
authors.forename: Michael A
authors.initials: MA
authors.lastname: Akeroyd
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D001309:Auditory Threshold / Q000502:physiology; D005260:Female; D006309:Hearing / Q000502:physiology; D006310:Hearing Aids; D006311:Hearing Disorders / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D008297:Male; D009622:Noise; D010700:Phonetics; D011571:Psychoacoustics; D013067:Speech Perception / Q000502:physiology*