title: Evaluation of speech recognition in noise with cochlear implants and dynamic FM.
abstract: BACKGROUND
  Use of personal frequency-modulated (FM) systems significantly improves speech recognition in noise for users of cochlear implants (CIs). Previous studies have shown that the most appropriate gain setting on the FM receiver may vary based on the listening situation and the manufacturer of the CI system. Unlike traditional FM systems with fixed-gain settings, Dynamic FM automatically varies the gain of the FM receiver with changes in the ambient noise level. There are no published reports describing the benefits of Dynamic FM use for CI recipients or how Dynamic FM performance varies as a function of CI manufacturer.
  
  
  OBJECTIVE
  To evaluate speech recognition of Advanced Bionics Corporation or Cochlear Corporation CI recipients using Dynamic FM vs. a traditional FM system and to examine the effects of Autosensitivity on the FM performance of Cochlear Corporation recipients.
  
  
  METHODS
  A two-group repeated-measures design. Participants were assigned to a group according to their type of CI.
  
  
  METHODS
  Twenty-five subjects, ranging in age from 8 to 82 years, met the inclusion criteria for one or more of the experiments. Thirteen subjects used Advanced Bionics Corporation, and 12 used Cochlear Corporation implants.
  
  
  METHODS
  Speech recognition was assessed while subjects used traditional, fixed-gain FM systems and Dynamic FM systems.
  
  
  METHODS
  In Experiments 1 and 2, speech recognition was evaluated with a traditional, fixed-gain FM system and a Dynamic FM system using the Hearing in Noise Test sentences in quiet and in classroom noise. A repeated-measures analysis of variance (ANOVA) was used to evaluate effects of CI manufacturer (Advanced Bionics and Cochlear Corporation), type of FM system (traditional and dynamic), noise level, and use of Autosensitivity for users of Cochlear Corporation implants. Experiment 3 determined the effects of Autosensitivity on speech recognition of Cochlear Corporation implant recipients when listening through the speech processor microphone with the FM system muted. A repeated-measures ANOVA was used to examine the effects of signal-to-noise ratio and Autosensitivity.
  
  
  RESULTS
  In Experiment 1, use of Dynamic FM resulted in better speech recognition in noise for Advanced Bionics recipients relative to traditional FM at noise levels of 65, 70, and 75 dB SPL. Advanced Bionics recipients obtained better speech recognition in noise with FM use when compared to Cochlear Corporation recipients. When Autosensitivity was enabled in Experiment 2, the performance of Cochlear Corporation recipients was equivalent to that of Advanced Bionics recipients, and Dynamic FM was significantly better than traditional FM. Results of Experiment 3 indicate that use of Autosensitivity improves speech recognition in noise of signals directed to the speech processor relative to no Autosensitivity.
  
  
  CONCLUSIONS
  Dynamic FM should be considered for use with persons with CIs to improve speech recognition in noise. At default CI settings, FM performance is better for Advanced Bionics recipients when compared to Cochlear Corporation recipients, but use of Autosensitivity by Cochlear Corporation users results in equivalent group performance.
authors.affiliation: Hearts for Hearing Foundation, USA. jace.wolfe@heartsforhearing.org
authors.forename: Jace
authors.initials: J
authors.lastname: Wolfe
authors.forename: Erin C
authors.initials: EC
authors.lastname: Schafer
authors.forename: Benjamin
authors.initials: B
authors.lastname: Heldner
authors.forename: Hans
authors.initials: H
authors.lastname: Mülder
authors.forename: Emily
authors.initials: E
authors.lastname: Ward
authors.forename: Brandon
authors.initials: B
authors.lastname: Vincent
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000669:Amplifiers, Electronic; D001302:Audiometry, Speech; D002648:Child; D003054:Cochlear Implants; D003638:Deafness / Q000503:physiopathology* / Q000628:therapy*; D005260:Female; D006801:Humans; D008144:Loudness Perception / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009622:Noise; D017060:Patient Satisfaction; D011474:Prosthesis Design; D012815:Signal Processing, Computer-Assisted; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult