title: Using multichannel wide-dynamic range compression in severely hearing-impaired listeners: effects on speech recognition and quality.
abstract: OBJECTIVE
  The objective of this study was to compare speech recognition across a sampling of amplification choices available for listeners with severe loss. This includes conventional options (linear with peak clipping and linear with compression limiting) and newer strategies (multichannel wide-dynamic range compression [WDRC]) theorized to better accommodate reduced dynamic range. A second objective was to compare speech quality across the same conditions using a paired-comparison test.
  
  
  METHODS
  Participants were 13 adults with severe sensorineural hearing loss and a control group of seven adults with normal hearing. Test materials included consonant-vowel syllables (speech recognition) and sentences (speech quality). Four amplification conditions were included: peak clipping; compression limiting; two-channel WDRC; and three-channel WDRC, with overall audibility similar across conditions. In the WDRC conditions, the compression ratio was fixed at 3:1 in each channel. Consonant recognition was measured using a closed-set task, and speech quality was measured using a paired-comparison test.
  
  
  RESULTS
  For the listeners with severe loss, recognition and preference were lower for a three-channel WDRC system than for a compression limiting system. Specific errors were consistent with poorer transmission of amplitude envelope information by the multichannel WDRC systems.
  
  
  CONCLUSIONS
  Under some conditions, the benefit of fast-acting, multichannel WDRC systems relative to more linear amplification strategies may be reduced in listeners with severe loss. Performance decrements with these systems are consistent with consequences of broader auditory filters.
authors.affiliation: Department of Speech and Hearing Sciences, University of Washington, Seattle, Washington 98105, USA.
authors.forename: Pamela E
authors.initials: PE
authors.lastname: Souza
authors.forename: Lorienne M
authors.initials: LM
authors.lastname: Jenstad
authors.forename: Richard
authors.initials: R
authors.lastname: Folino
mesh_terms: D000161:Acoustic Stimulation / Q000295:instrumentation; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006310:Hearing Aids / Q000592:standards*; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010700:Phonetics; D011474:Prosthesis Design; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013067:Speech Perception; D013069:Speech Reception Threshold Test