title: The speech intelligibility benefit of a unilateral wireless system for hearing-impaired adults.
abstract: OBJECTIVE
  This study measured the effects of two previously untested practical considerations-venting and transmission delays-on speech intelligibility in a simulated unilateral wireless system, where a target signal in background noise was transmitted wirelessly to the hearing-impaired (HI) listener.
  
  
  METHODS
  Speech reception thresholds (SRTs) relative to the signal-to-noise ratio (SNR) were measured by varying the surrounding babble noise level. The target signal was presented at 0° azimuth in the soundfield and unilaterally via an insert earphone, using open and closed fittings with simulated-wireless delays ranging between 0-160 ms. SRTs were also measured unaided and with participants' current hearing aid(s).
  
  
  METHODS
  Thirty-three mild-to-moderate sensorineural HI adults participated in the experiment.
  
  
  RESULTS
  For an open fitting, the results showed a 5-dB SNR benefit in SRT compared to unaided performance at shorter delays. For a closed fitting, the majority of participants could accurately recognize speech below - 20 dBSNR across delays.
  
  
  CONCLUSIONS
  These results highlight the efficacy of wireless systems with HI adults. Speech-intelligibility benefits are affected by transmission delays only when the delay is greater than 40 ms and the coupling is vented.
authors.affiliation: MRC Institute of Hearing Research (Scottish Section), Glasgow, UK. bill@ihr.gla.ac.uk
authors.forename: William M
authors.initials: WM
authors.lastname: Whitmer
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Brennan-Jones
authors.forename: Michael A
authors.initials: MA
authors.lastname: Akeroyd
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D034381:Hearing Loss / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D013061:Speech Acoustics; D013067:Speech Perception; D059015:Wireless Technology