title: The effect on localization of frequency-specific gain reduction schemes when matched and mismatched across ears.
abstract: OBJECTIVE
  To evaluate the impact of non-adaptive matched and mismatched gain reduction schemes on localization in spatially-separated noise.
  
  
  METHODS
  Inspired by the function of commercial noise reduction algorithms, five frequency-specific gain reduction filter schemes were created, three for a modulated babble-noise and two for an unmodulated speech-shaped noise. Applying these schemes as both matched and mismatched conditions across ears, localization of five everyday sounds in noise was measured in a virtual environment using insert earphones. The performance in the reference scheme (no gain reduction in either ear) was measured as well.
  
  
  METHODS
  Twenty-four adult bilateral hearing-aid users were enrolled in this study.
  
  
  RESULTS
  One of the two mismatched gain reduction schemes for the unmodulated noise had a small but negative impact on localization compared to the reference scheme. For that scheme more high-frequency reduction was noted than for the other schemes. Matching gain reduction across ears restored the deteriorated localization performance. No localization performance differences were observed in the modulated babble-noise regardless of whether the scheme was matched or mismatched across ears.
  
  
  CONCLUSIONS
  The impact of noise-induced gain reduction on localization in noise was trivial in the study regardless of whether gain reduction schemes were matched or not across ears.
authors: * Department of Communication Sciences and Disorders, Illinois State University , Normal, Illinois , USA.
authors: Hua
authors: H
authors: Ou
authors: Ruth A
authors: RA
authors: Bentler
authors: Shawn S
authors: SS
authors: Goodman
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D012048:Correction of Hearing Impairment / Q000295:instrumentation; D005260:Female; D006310:Hearing Aids; D006312:Hearing Loss, Bilateral / Q000503:physiopathology* / Q000534:rehabilitation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects*; D013017:Sound Localization / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology
keywords: Hearing aid; bilateral gain reduction; localization