title: Sentence recognition in noise and perceived benefit of noise reduction on the receiver and transmitter sides of a BICROS hearing aid.
abstract: BACKGROUND
  In the past, bilateral contralateral routing of signals (BICROS) amplification incorporated omnidirectional microphones on the transmitter and receiver sides and some models utilized noise reduction (NR) on the receiver side. Little research has examined the performance of BICROS amplification in background noise. However, previous studies examining contralateral routing of signals (CROS) amplification have reported that the presence of background noise on the transmitter side negatively affected speech recognition. Recently, NR was introduced as a feature on the receiver and transmitter sides of BICROS amplification, which has the potential to decrease the impact of noise on the wanted speech signal by decreasing unwanted noise directed to the transmitter side.
  
  
  OBJECTIVE
  The primary goal of this study was to examine differences in the reception threshold for sentences (RTS in dB) using the Hearing in Noise Test (HINT) in a diffuse listening environment between unaided and three aided BICROS conditions (no NR, mild NR, and maximum NR) in the Tandem 16 BICROS. A secondary goal was to examine real-world subjective impressions of the Tandem 16 BICROS compared to unaided.
  
  
  METHODS
  A randomized block repeated measures single blind design was used to assess differences between no NR, mild NR, and maximum NR listening conditions.
  
  
  METHODS
  Twenty-one adult participants with asymmetric sensorineural hearing loss (ASNHL) and experience with BICROS amplification were recruited from Washington University in St. Louis School of Medicine.
  
  
  METHODS
  Participants were fit with the National Acoustic Laboratories' Nonlinear version 1 prescriptive target (NAL-NL1) with the Tandem 16 BICROS at the initial visit and then verified using real-ear insertion gain (REIG) measures. Participants acclimatized to the Tandem 16 BICROS for 4 wk before returning for final testing. Participants were tested utilizing HINT sentences examining differences in RTS between unaided and three aided listening conditions. Subjective benefit was determined via the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire between the Tandem 16 BICROS and unaided. A repeated measures analysis of variance (ANOVA) was utilized to analyze the results of the HINT and APHAB.
  
  
  RESULTS
  Results revealed no significant differences in the RTS between unaided, no NR, mild NR, and maximum NR. Subjective impressions using the APHAB revealed statistically and clinically significant benefit with the Tandem 16 BICROS compared to unaided for the Ease of Communication (EC), Background Noise (BN), and Reverberation (RV) subscales.
  
  
  CONCLUSIONS
  The RTS was not significantly different between unaided, no NR, mild NR, and maximum NR. None of the three aided listening conditions were significantly different from unaided performance as has been reported for previous studies examining CROS hearing aids. Further, based on comments from participants and previous research studies with conventional hearing aids, manufacturers of BICROS amplification should consider incorporating directional microphones and independent volume controls on the receiver and transmitter sides to potentially provide further improvement in signal-to-noise ratio (SNR) for patients with ASNHL.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Division of Adult Audiology, Washington University in St. Louis School of Medicine.
authors.forename: Kristi
authors.initials: K
authors.lastname: Oeding
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Division of Adult Audiology, Washington University in St. Louis School of Medicine.
authors.forename: Michael
authors.initials: M
authors.lastname: Valente
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D005260:Female; D006310:Hearing Aids; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D009622:Noise / Q000009:adverse effects / Q000517:prevention & control*; D017060:Patient Satisfaction / Q000706:statistics & numerical data; D011474:Prosthesis Design; D017755:Prosthesis Fitting / Q000379:methods; D012720:Severity of Illness Index; D059629:Signal-To-Noise Ratio; D016037:Single-Blind Method; D013017:Sound Localization / Q000502:physiology; D013067:Speech Perception / Q000502:physiology*; D013069:Speech Reception Threshold Test / Q000379:methods / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D016896:Treatment Outcome