In this study we used functional near-infrared spectroscopy (fNIRS) to investigate neural responses in normal-hearing adults as a function of speech recognition accuracy, intelligibility of the speech stimulus, and the manner in which speech is distorted. Participants listened to sentences and reported aloud what they heard. Speech quality was distorted artificially by vocoding (simulated cochlear implant speech) or naturally by adding background noise. Each type of distortion included high and low-intelligibility conditions. Sentences in quiet were used as baseline comparison. fNIRS data were analyzed using a newly developed image reconstruction approach. First, elevated cortical responses in the middle temporal gyrus (MTG) and middle frontal gyrus (MFG) were associated with speech recognition during the low-intelligibility conditions. Second, activation in the MTG was associated with recognition of vocoded speech with low intelligibility, whereas MFG activity was largely driven by recognition of speech in background noise, suggesting that the cortical response varies as a function of distortion type. Lastly, an accuracy effect in the MFG demonstrated significantly higher activation during correct perception relative to incorrect perception of speech. These results suggest that normal-hearing adults (i.e., untrained listeners of vocoded stimuli) do not exploit the same attentional mechanisms of the frontal cortex used to resolve naturally degraded speech and may instead rely on segmental and phonetic analyses in the temporal lobe to discriminate vocoded speech.

Purpose: The purpose of the study was to determine the effect of hearing aid technology level on listener outcome measures. In addition, we aimed to determine if individual characteristics such as noise acceptance and the demands of the listening environment impacted performance and preference.Method: A repeated-measures, single-blinded research design was utilized. Twenty-four adults recruited by mail from The University of Tennessee Health Science Center Audiology Clinic participated in this experiment (15 men and nine women). Participants completed two 2-week trial periods using Unitron T Moxi Fit FLEX:TRIAL devices programmed as basic or premium technology levels. A data-logging feature, Log It All (LIA), quantified the demands of the listening environment. At the end of each trial, outcome measures were obtained using Pascoe's High-Frequency Word List, the Hearing in Noise Test, the Quick Speech-in-Noise Test, the Acceptable Noise Level (ANL), the Speech, Spatial and Qualities of Hearing short form, satisfaction ratings, and preference.Results: Results for ANL, satisfaction in large groups, and LIA total coverage were significantly improved for the premium devices. Participants who preferred the premium devices received significant improvement with premium devices on the ANL and the speech in small group and speech in large group satisfaction ratings, whereas participants who preferred the basic devices did not receive significant improvement with premium devices on any outcome measure. Participants in more demanding listening environments received significant improvement with premium devices on the ANL, whereas participants in less demanding listening environments did not receive significant improvement with premium devices on any outcome measure.Conclusions: Group data revealed similar outcomes between technology levels on most measures; however, noise acceptance and satisfaction for speech in a large group were significantly improved when using the premium devices. Individual characteristics such as noise acceptance and listening demands may be useful when comparing hearing aid technology levels for a given patient.

Background:Nonlinear frequency compression (NLFC) and digital noise reduction (DNR) are hearing aid features often used simultaneously in the adult population with hearing loss. Although each feature has been studied extensively in isolation, the effects of using them in combination are unclear.Purpose:The effects of NLFC and DNR in noise on word recognition and satisfaction ratings in noise in adult hearing aid users were evaluated.Research Design:A repeated measures design was used.Study Sample:Two females and 13 males between the ages of 55 and 83 yr who were experienced hearing aid users participated. Thirteen were experienced with NLFC and all were experienced with DNR. Each participant was fit with Phonak Bolero Q90-P hearing instruments using their specific audiometric data and the Desired Sensation Level v5.0 (adult) fitting strategy. Fittings were verified with probe microphone measurements using speech at 65-dB sound pressure level (SPL). NLFC verification was performed using the Protocol for the Provision of Amplification, Version 2014.01.Data Collection and Analysis:All testing was conducted in a double-walled sound booth. Four hearing aid conditions were used for all testing: Baseline (NLFC off, DNR off), NLFC only, DNR only, and Combination (NLFC on, DNR on). A modified version of the Pascoe’s High-Frequency Word List was presented at 65-dB SPL with speech spectrum noise at 6-dB signal-to-noise ratio (SNR) and 1-dB SNR for each hearing aid condition. Listener satisfaction ratings were obtained after each listening condition in terms of word comfort, word clarity, and average satisfaction. Two-way repeated measures analyses of variance were conducted to assess listener performance. Pairwise comparisons were then completed for significant main effects.Results:Word recognition results indicated a significant SNR effect only (6 dB SNR > 1 dB SNR). Satisfaction ratings results indicated a significant SNR and hearing aid condition effect for clarity, comfort, and average satisfaction. Clarity ratings were significantly higher for DNR and Combination than NLFC. Comfort ratings were significantly higher for DNR than NLFC. Average satisfaction was significantly higher for DNR and Combination than for NLFC. Also, average ratings were significantly higher for Combination than Baseline.Conclusions:Activating NLFC or DNR in isolation or in combination did not significantly impact word recognition in noise. Activating NLFC in isolation reduced satisfaction ratings relative to the DNR or Combination conditions. The isolated use of DNR significantly improved all satisfaction ratings when compared with the isolated use of NLFC. These findings suggest NLFC should not be used in isolation and should be coupled with DNR for best results. Future research should include a field trial as this was a limitation of the study.

Objective: The aim of this study was to determine the relation between the acceptable noise level (ANL) and cognitive measures of auditory attention and working memory. Design: Young adults were administered the following tests: the ANL, the Digit Span and Letter–Number Sequencing subtests of the Wechsler Adult Intelligence Scale–Fourth Edition, the Auditory Attention subtest from the Woodcock-Johnson Tests of Cognitive Abilities, the Hearing in Noise Test (HINT), and the operation span (OSPAN) test. A correlation matrix was constructed using Pearson coefficients. Study sample: Twenty-four young adults aged 20–29 years with normal hearing participated in the study. Results: No significant relationships were found among the ANL and the different cognitive tasks, nor was there a significant relation found between the ANL and the HINT. However, significant relationships were found between individual cognitive tasks. There was a significant relation found between selective attention and the most comfortable level of presentation of a story. Conclusion: Selective attention may be a key cognitive function in acceptance of background noise.

Background:Digital hearing aids using a 16-bit analog-to-digital converter (ADC) provide a 96-dB input dynamic range. The level at which the ADC peak clips and distorts input signals ranges between 95 and 105 dB SPL. Recent research evaluated the effect of extending the input dynamic range in a commercially available hearing aid. Although the results were promising, several limitations were noted by the authors. Laboratory testing was conducted using recordings from hearing aids set for a flat 50-dB loss; however, field testing was conducted with hearing aids fitted for their hearing loss. In addition, participants rarely encountered input levels of sufficient intensity to adequately test the feature and were unable to directly compare aids with and without extended input dynamic range (EIDR) under identical conditions.Purpose:The effects of EIDR under realistic and repeatable test conditions both within and outside the laboratory setting were evaluated.Research Design:A repeated measures design was used. The experiment was single-blinded.Study Sample:Twenty adults (14 males and six females) between the ages of 30 and 71 years (average age 62 years) who were experienced hearing aid users participated.Data Collection and Analysis:Each participant was fit with Oticon Opn hearing instruments binaurally using the National Acoustics Laboratory-Nonlinear 1 fitting strategy. Participants completed a two-week trial period using hearing aids with EIDR and a two-week trial period without EIDR. The initial EIDR condition trial period was counterbalanced. After each trial, laboratory evaluations were obtained at 85 dBC using the Connected Speech Test, the Hearing in Noise Test, and the acceptable noise level (ANL). Satisfaction ratings were conducted at 85 dBC using speech in quiet and in noise as well as music. Field-trial evaluations were obtained using the abbreviated profile of hearing aid benefit (APHAB). Satisfaction ratings were also conducted in the field at 85 dBC using speech and music. After the study, each participant indicated which trial period they preferred overall. Repeated measures analysis of variances were conducted to assess listener performance. Pairwise comparisons were then completed for significant main effects.Results:In the laboratory, results did not reveal significant differences between EIDR conditions on any speech perception in noise test or any satisfaction rating measurement. In the field, results did not reveal significant differences between the EIDR conditions on the APHAB or on any of the satisfaction rating measurements. Nine participants (45%) preferred the EIDR condition. Fifteen participants (75%) indicated that speech clarity was the most important factor in determining the overall preference. Sixteen participants (80%) preferred the EIDR condition that resulted in the lower ANL.Conclusions:The use of EIDR in hearing aids within and outside the laboratory under realistic and repeatable test conditions did not positively or negatively impact performance or preference. Results disagreed with previous findings obtained in the laboratory that suggested EIDR improved performance; however, results agreed with previous findings obtained in the field. Future research may consider the effect of hearing aid experience, input level, and noise acceptance on potential benefit with EIDR.

Purpose: The purpose of this study was to determine the effectiveness of television (TV) streaming on hearing aid user performance and satisfaction in quiet and in noise.Method: Twenty experienced hearing aid users were evaluated in quiet and in noise (5 dB SNR) under three hearing aid conditions: hearing aids, streaming with hearing aid microphones attenuated by 6 dB, and streaming with hearing aid microphones muted. The audiovisual Connected Speech Test served as the signal, and the ipsilateral competing message from the Synthetic Sentence Identification—Ipsilateral Competing Message (SSI-ICM) served as the noise. Measures of speech understanding, satisfaction with sound quality and clarity, and preference were obtained.Results: Speech understanding was significantly better in quiet than in noise, and streaming improved performance in noise when the hearing aid microphones were muted. Sound quality satisfaction was significantly better in quiet than in noise but was not impacted significantly by the hearing aid settings. Speech clarity satisfaction was significantly better in quiet than in noise, and streaming improved satisfaction in noise when the hearing aid microphones were muted. More participants preferred streaming with the microphones muted in quiet, in noise, and overall; however, results did not reach statistical significance.Conclusions: Hearing aid users did not benefit from TV streaming with the microphones attenuated or muted when listening in quiet. TV streaming was more beneficial to hearing aid users when listening in noise with the microphones muted. Hearing aid users should be counseled on the impact of the hearing aid microphone settings when using a TV streamer, particularly in noise.