title: Effects of user training with electronically-modulated sound transmission hearing protectors and the open ear on horizontal localization ability.
abstract: OBJECTIVE
  To determine if training with electronically-modulated hearing protection (EMHP) and the open ear results in auditory learning on a horizontal localization task.
  
  
  METHODS
  Baseline localization testing was conducted in three listening conditions (open-ear, in-the-ear (ITE) EMHP, and over-the-ear (OTE) EMHP). Participants then wore either an ITE or OTE EMHP for 12, almost daily, one-hour training sessions. After training was complete, participants again underwent localization testing in all three listening conditions. A computer with a custom software and hardware interface presented localization sounds and collected participant responses.
  
  
  METHODS
  Twelve participants were recruited from the student population at Virginia Tech. Audiometric requirements were 35 dBHL at 500, 1000, and 2000 Hz bilaterally, and 55 dBHL at 4000 Hz in at least one ear.
  
  
  RESULTS
  Pre-training localization performance with an ITE or OTE EMHP was worse than open-ear performance. After training with any given listening condition, including open-ear, performance in that listening condition improved, in part from a practice effect. However, post-training localization performance showed near equal performance between the open-ear and training EMHP. Auditory learning occurred for the training EMHP, but not for the non-training EMHP; that is, there was no significant training crossover effect between the ITE and the OTE devices.
  
  
  CONCLUSIONS
  It is evident from this study that auditory learning (improved horizontal localization performance) occurred with the EMHP for which training was performed. However, performance improvements found with the training EMHP were not realized in the non-training EMHP. Furthermore, localization performance in the open-ear condition also benefitted from training on the task.
authors.affiliation: * Auditory Systems Lab, Virginia Polytechnic Institute and State University (Virginia Tech) , Blacksburg , USA.
authors.forename: John G
authors.initials: JG
authors.lastname: Casali
authors.forename: Martin B
authors.initials: MB
authors.lastname: Robinette
mesh_terms: D000328:Adult; D004430:Ear Protective Devices; D005260:Female; D006801:Humans; D007858:Learning; D008297:Male; D013017:Sound Localization; D055815:Young Adult
keywords: Auditory learning; TCAPS; active HPDs; electronically modulated; hearing protection; interaural level differences; interaural time differences; localization; sensory adaptation; warfighter