title: To measure the impact of hearing protectors on the perception of speech in noise.
abstract: OBJECTIVE
  To propose and evaluate a new method for assessing the potential impact on speech intelligibility when wearing a hearing protection device (HPD) in a noisy environment.
  
  
  METHODS
  The method is based on a self adaptive method for finding the speech reception threshold (SRT) using speech material from the Callsign acquisition test (CAT) presented at a constant level while adjusting the level of a background noise. A key point is to primarily examine the impact of the HPD; i.e. the difference between occluded and unoccluded SRTs, presented as the speech intelligibility impact level.
  
  
  METHODS
  A total of 31 test subjects.
  
  
  RESULTS
  The method is shown to be stable, with a minimum amount of learning effect, and capable of detecting differences between hearing protection devices. It is also shown that low-attenuation passive HPDs are likely to have a very small effect on speech intelligibility in noise, and that an electronic HPD with a level-dependant function has the potential to improve intelligibility.
  
  
  CONCLUSIONS
  The results are encouraging regarding the precision, repeatability, and applicability of the proposed method.
authors.affiliation: * 3M Personal Safety Division, 3M Svenska AB , Box, Värnamo , Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Hiselius
authors.forename: Niklas
authors.initials: N
authors.lastname: Edvall
authors.forename: Daniel
authors.initials: D
authors.lastname: Reimers
mesh_terms: D004430:Ear Protective Devices; D005260:Female; D006801:Humans; D008297:Male; D009622:Noise; D013067:Speech Perception
keywords: Hearing protection devices; learning effect; speech intelligibility; speech intelligibility impact level; speech reception threshold