Sound Booth Research Articles

Models for Estimating the Hearing Threshold of Quarry Workers at High Frequencies

It is widely known that quarry industry has great importance in developing countries, such as Nigeria. There is paucity of information regarding effects of noise experienced by quarry workers during their working time. Therefore, this study investigated the influence of age of workers, years of exposure of workers and noise level of the machine used in quarry on hearing threshold. A factorial design of experiment was employed for the investigation. Two hundred and four quarry workers volunteered for this study from four quarries in South western Nigeria. Emitted noise, which quarry workers were exposed to during machinery operation, was measured with a digital sound level meter and workers hearing threshold was measured in an audiogram sound proofing testing booth at standard conditions. Predicted models were established from experimental design to determine main and interactions effects towards the response (hearing threshold). These were statistically analysed using analysis of variance (ANOVA). All terms of the models were significant at p<0.05. The best fitted model was at 4kHz (R2 = 0.639, p<0.05). The magnitudes of the main effect of the factors are in ascending order of noise level >years of exposure>age. The analysis of the experimental response indicated that there is no interaction of any factors on the hearing threshold. It can be concluded that age, years of exposure and noise level have main effects at various capacities at different frequency to predict the hearing threshold of the quarry workers. This work determined the factors and the predicted model to spell out safe hearing threshold of quarry workers that fitted for the job at a particular noisy workstation as well as ensuring comfortable, safe and effective workstation design.

Comparisons of Auditory Brainstem Responses Between a Laboratory and Simulated Home Environment.

Purpose Miniaturization of digital technologies has created new opportunities for remote health care and neuroscientific fieldwork. The current study assesses comparisons between in-home auditory brainstem response (ABR) recordings and recordings obtained in a traditional lab setting. Method Click-evoked and speech-evoked ABRs were recorded in 12 normal-hearing, young adult participants over three test sessions in (a) a shielded sound booth within a research lab, (b) a simulated home environment, and (c) the research lab once more. The same single-family house was used for all home testing. Results Analyses of ABR latencies, a common clinical metric, showed high repeatability between the home and lab environments across both the click-evoked and speech-evoked ABRs. Like ABR latencies, response consistency and signal-to-noise ratio (SNR) were robust both in the lab and in the home and did not show significant differences between locations, although variability between the home and lab was higher than latencies, with two participants influencing this lower repeatability between locations. Response consistency and SNR also patterned together, with a trend for higher SNRs to pair with more consistent responses in both the home and lab environments. Conclusions Our findings demonstrate the feasibility of obtaining high-quality ABR recordings within a simulated home environment that closely approximate those recorded in a more traditional recording environment. This line of work may open doors to greater accessibility to underserved clinical and research populations.

Identification of unreliable subject data from remote testing

The less controlled nature of conducting behavioral testing outside of the typical sound booth and not under the direct observation of the experimenter introduces additional factors that may lead to unreliable data. These factors arise from the environment (e.g., room acoustics and background noise), the participant (e.g., attention, engagement, and understanding of the task), and the testing apparatus (e.g., calibration and network latency). Remote-testing protocols should include features to allow for the detection of unreliable data. To aid in the detection of unreliable data in future remote-testing protocols, we retrospectively examined a large dataset (N > 1000) of speech intelligibility and tone-in-noise detection that was collected over headphones with a tablet-based system in a waiting room environment. The dataset provides the ability to determine the extent to which unreliable data can be detected based on the presence of high levels of background noise during the testing, abnormally short response times, high lapse rates, flat psychometric functions, and patterns in the response sequence. [The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army/Navy/Air Force, Department of Defense, or U.S. Government.]

The spoken language research laboratories (SLRL) at the University of Oregon

The Spoken Language Research Laboratories (SLRL) at the University of Oregon houses 5 integrated laboratories that focus onspeech communication. The SLRL occupies nearly 4000 square feet and includes the following state-of-the-art facilities: 10 sound-attenuated subject running rooms; 3 sound-attenuated (clinical-type) observation rooms; 2 single-wall sound booths in another sound attenuated room; 2 waiting rooms; 1 large computer lab; 2 graduate student workrooms; and 8 offices. The SLRL is further equipped with all necessary high-quality audio and audio-visual recording equipment. Research at the SLRL ranges from work on language variation and change to first and second language acquisition to the perception and production of spoken language. The labs provide a dynamic, supportive environment for collaborative research and training in experimental design, acoustic and speech movement analysis, statistical analysis, grant writing, science communication and community outreach. The SLRL is embedded in a vibrant language research community at the University of Oregon (UO) that is anchored in the Linguistics Department, but spread over multiple departments, including East Asian Languages & Literatures, Romance Languages & Literatures, and Communication Disorders & Sciences. The UO and the SLRL provide a myriad of research opportunities for students interested in spoken language behavior.

Evaluation of Portable Tablet-Based Audiometry in a South Indian Population.

While a comprehensive booth audiogram is the gold standard for diagnosis of hearing loss, access to this may not be available in remote and low resource settings. The aims of this study were to validate a tablet-based audiometer in a tertiary medical center in India and explore its capacity in improving access to hearing healthcare. Subjects presenting to Ear-Nose-Throat clinics for conventional booth audiometry testing were recruited for subsequent tablet-based audiometric testing. Testing with the tablet was conducted in a non-sound-treated hospital clinic room. Bilateral air and bone conduction hearing threshold data from 250 through 4000Hz were validated against conventional booth audiometry. In addition, a small feasibility study was conducted in rural clinics. 70 participants (37 adults and 33 children between the ages 5-18) were assessed. 69% were male, with a mean age of 29.7years. Sensitivity and specificity for the tablet were 89% (95% CI 80-94%) and 70% (95% CI 56-82%), respectively. While median differences in air conduction thresholds between conventional and tablet audiograms showed statistical significance at 250, 500, and 1000Hz (p < 0.001), the threshold results of the tablet audiometer were within 5dB of the conventional audiogram and not clinically significant. Ten patients were successfully screened in rural clinics with tablet audiometry. Tablet portable audiometry is a valid tool for air and bone conduction threshold assessment outside of conventional sound booths. It can accurately identify hearing impairment and offers a screening tool for hearing loss in low resource settings.

Total remission or persistence of tinnitus and decreased sound level tolerance in adolescents with normal audiograms: A follow-up study.

Tinnitus may reflect hidden cochlear synaptic injury that does not express in the audiogram, but leads to neuroplastic changes in auditory pathways that, in turn, reduce tolerance to sounds. Such injury may follow the exposure to loud sounds. The aim of this study was to follow-up adolescents enrolled in a private school to evaluate the prevalence of tinnitus and reduced sound level tolerance (SLT) with 1-year interval, as well as to observe rates of tinnitus persistence, remission and incidence of new cases by repeat measurements. In Study 1 (Sanchez et al., 2016), we evaluated 170 adolescents by a questionnaire about tinnitus and reduced tolerance to ordinary sounds and by measurements in a sound booth: audiometry (0.25-16kHz), Loudness Discomfort Levels (LDL, 0.5-4kHz) and tinnitus pitch/loudness matching (if present). Tinnitus measured in the booth was then called "confirmed tinnitus." In Study 2, we revaluated 54 adolescents who returned voluntarily 1 year later to repeat all measurements. From Study 1 to 2, the prevalence of confirmed tinnitus reduced from 28.8% (49/170) to 14.9% (8/54) in retested subjects, which includes the cases of persisting tinnitus (confirmed tinnitus in both studies, n=6/54=11.2%) and the new cases of tinnitus (confirmed tinnitus just at Study 2, n=2/54=3.7%). Among the 15 adolescents with confirmed tinnitus at Study 1 who returned for Study 2, 40% had persistent tinnitus (n=6) and 60% did not (remitted tinnitus, n=9). SLT was reduced by 17.3dB in cases with persistent tinnitus (P<0.0002), similar to the findings of Study 1, and returned to normal levels in subjects with remitted tinnitus. Hearing thresholds averaged 4.37dBHL and were <20dBHL in 97% of ears and all frequencies. At 14 and 16kHz thresholds were bilaterally elevated at Study 1 (5.07dB) and 2 (5.56dB) in adolescents with confirmed tinnitus. Tinnitus and reduced sound tolerance could feature early signals of hidden synaptic injury that is prevalent among adolescents and hidden from the audiogram. The strong relationship between both symptoms, in addition to low-level increases in hearing thresholds at high frequencies in the extended audiogram, poses a challenge for future hearing health and should be further evaluated as a possible intrinsic vulnerability for lesions following exposure to loud sounds. Moreover, the relationship between their spontaneous remissions may signal a possible synaptic repair, which has been reported in animal models.

Making Audiology Work During COVID-19 and Beyond

Making Audiology Work During COVID-19 and Beyond

The Effect of Unilateral Hearing Protection on Vocal Intensity With Varying Degrees of Background Noise

The Lombard effect (LE) is a phenomenon in which speakers adjust their vocal production by raising the volume in noisy environments. As a result, the LE can create problems of vocal strain, fatigue and potential injury. This study aims to examine the difference in vocal intensity output in subjects wearing unilateral hearing protection versus no hearing protection in the presence of background noise. Each subject was seated inside a sound booth wearing a head-mounted microphone. Subjects were asked to read an excerpt from "The Rainbow Passage" while various levels of background noise were played: 50, 60, 70, and 80 dBA (Multitalker Babble). Each noise level was played while the subject was with and without unilateral ear protection (Optime 98 Earmuff [3M]) in random order. The earmuff has a noise reduction rating of 25 dB. After each reading of the text, subjects were asked to rate communication disturbance, vocal clarity, and discomfort during talking using a 10 cm visual analogue scale. The LE is reduced from 0.38 dB/dB to 0.29 dB/dB with unilateral ear occlusion. However, self-perception of disturbance, clarity and comfort were not affected by unilateral occlusion, only by noise level. Unilateral hearing protection reduces the LE and may protect against phonotrauma when speaking in an environment with loud background noise.

Reliability of Tablet-based Hearing Testing in Nicaraguan Schoolchildren: A Detailed Analysis.

Determine whether an electronic tablet-based Wireless Automated Hearing-Test System can perform high-quality audiometry to assess schoolchildren for hearing loss in the field in Nicaragua. Cross-sectional. A school and hospital-based audiology clinic in Jinotega, Nicaragua. Second and third graders (n = 120) were randomly selected for hearing testing in a school. Air conduction hearing thresholds were obtained bilaterally using a Wireless Automated Hearing-Test System at 1000, 2000, and 4000 Hz. Referral criteria were set at more than 25 dBHL at one or more frequencies. A cohort of children was retested with conventional audiometry in a hospital-based sound booth. Factors influencing false-positive examinations, including ambient noise and behavior, were examined. All children with hearing loss were detected using an automated, manual, or two-step (those referred from automated testing were tested manually) protocol in the school (sensitivity = 100%). Specificity was 76% for automated testing, 97% for manual testing, and 99% for the two-step protocol. The variability between thresholds obtained with automated testing was greater than manual testing when compared with conventional audiometry. The percentage of participant responses when no stimulus tone was presented during automated testing was higher in children with false-positive examinations. A Wireless Automated Hearing-Test System identified all children with hearing loss in a challenging field setting. A two-step protocol (those referred from automated testing are tested manually) reduced false-positive examinations and unnecessary referrals. Children who respond frequently when no tone is presented are more likely to have false-positive automated examinations and should be tested manually.

Activation in human auditory cortex in relation to the loudness and unpleasantness of low-frequency and infrasound stimuli

Low frequency noise (LFS) and infrasound (IS) are controversially discussed as potential causes of annoyance and distress experienced by many people. However, the perception mechanisms for IS in the human auditory system are not completely understood yet. In the present study, sinusoids at 32 Hz (at the lower limit of melodic pitch for tonal stimulation), as well as 8 Hz (IS range) were presented to a group of 20 normal hearing subjects, using monaural stimulation via a loudspeaker sound source coupled to the ear canal by a long silicone rubber tube. Each participant attended two experimental sessions. In the first session, participants performed a categorical loudness scaling procedure as well as an unpleasantness rating task in a sound booth. In the second session, the loudness scaling procedure was repeated while brain activation was measured using functional magnetic resonance imaging (fMRI). Subsequently, activation data were collected for the respective stimuli presented at fixed levels adjusted to the individual loudness judgments. Silent trials were included as a baseline condition. Our results indicate that the brain regions involved in processing LFS and IS are similar to those for sounds in the typical audio frequency range, i.e., mainly primary and secondary auditory cortex (AC). In spite of large variation across listeners with respect to judgments of loudness and unpleasantness, neural correlates of these interindividual differences could not yet be identified. Still, for individual listeners, fMRI activation in the AC was more closely related to individual perception than to the physical stimulus level.

The effect of an active transcutaneous bone conduction device on spatial release from masking

Objective: The aim was to quantify the effect of the experimental active transcutaneous Bone Conduction Implant (BCI) on spatial release from masking (SRM) in subjects with bilateral or unilateral conductive and mixed hearing loss.Design: Measurements were performed in a sound booth with five loudspeakers at 0°, +/−30° and +/−150° azimuth. Target speech was presented frontally, and interfering speech from either the front (co-located) or surrounding (separated) loudspeakers. SRM was calculated as the difference between the separated and the co-located speech recognition threshold (SRT).Study Sample: Twelve patients (aged 22–76 years) unilaterally implanted with the BCI were included.Results: A positive SRM, reflecting a benefit of spatially separating interferers from target speech, existed for all subjects in unaided condition, and for nine subjects (75%) in aided condition. Aided SRM was lower compared to unaided in nine of the subjects. There was no difference in SRM between patients with bilateral and unilateral hearing loss. In aided situation, SRT improved only for patients with bilateral hearing loss.Conclusions: The BCI fitted unilaterally in patients with bilateral or unilateral conductive/mixed hearing loss seems to reduce SRM. However, data indicates that SRT is improved or maintained for patients with bilateral and unilateral hearing loss, respectively.

Speech Perception in Classroom Acoustics by Children With Hearing Loss and Wearing Hearing Aids.

PurposeThe classroom acoustic standard ANSI/ASA S12.60-2010/Part 1 requires a reverberation time (RT) for children with hearing impairment of 0.3 s, shorter than its requirement of 0.6 s for children with typical hearing. While preliminary data from conference proceedings support this new RT requirement of 0.3 s, peer-reviewed data that support 0.3-s RT are not available on those wearing hearing aids. To help address this, this article compares speech perception performance by children with hearing aids in RTs, including those specified in the ANSI/ASA-2010 standard. A related clinical issue is whether assessments of speech perception conducted in near-anechoic sound booths, which may overestimate performance in reverberant classrooms, may now provide a more reliable estimate when the child is in a classroom with a short RT of 0.3 s. To address this, this study compared speech perception by children with hearing aids in a sound booth to listening in 0.3-s RT.MethodParticipants listened in classroom RTs of 0.3, 0.6, and 0.9 s and in a near-anechoic sound booth. All conditions also included a 21-dB range of speech-to-noise ratios (SNRs) to further represent classroom listening environments. Performance measures using the Bamford–Kowal–Bench Speech-in-Noise (BKB-SIN) test were 50% correct word recognition across these acoustic conditions, with supplementary analyses of percent correct.ResultsEach reduction in RT from 0.9 to 0.6 to 0.3 s significantly benefited the children's perception of speech. Scores obtained in a sound booth were significantly better than those measured in 0.3-s RT.ConclusionThese results support the acoustic standard of 0.3-s RT for children with hearing impairment in learning spaces ≤ 283 m3, as specified in ANSI/ASA S12.60-2010/Part 1. Additionally, speech perception testing in a sound booth did not predict accurately listening ability in a classroom with 0.3-s RT.Supplemental Material https://doi.org/10.23641/asha.11356487

Performance and Reliability of a Smartphone Digits-in-Noise Test in the Sound Field.

Purpose This study compared the speech reception thresholds (SRTs) and test-retest reliability of the smartphone digits-in-noise (DIN) test coupled to various sound-field transducers. Method Fifty normal-hearing participants (bilateral pure- tone thresholds 0.5-8kHz ≤ 15dB HL) between the ages of 18 and 25 years (M = 20, SD = ±1.9) were recruited. The study used a repeated measure counterbalanced Latin square design to compare the SRTs of the smartphone DIN test recorded with earphones, 2 smartphone speakers, and 2 external loudspeakers in a sound booth. Test-retest reliability across sound field conditions was also determined. Results Mean SRTs across earphone and different sound field transducers ranged from -11.3 (SD = 0.8) to -11.7 (SD = 1.2). SRTs across the 4 different loudspeaker transducers and earphones were not significantly different (p > .05) between test and retest sessions. Conclusion The smartphone DIN test is reliable and can be conducted using various sound field transducers in a sound booth. To allow home-based testing without earphones, with special application to aided performance for speech-in-noise testing, the smartphone DIN test should be evaluated in home environments.

Spectral-temporally modulated ripple test Lite for computeRless Measurement (SLRM): A Nonlinguistic Test for Audiology Clinics.

Many clinics are faced with the difficulty of evaluating performance in patients who speak a language for which there are no validated tests. It would be desirable to have a nonlinguistic method of evaluating these patients. Spectral ripple tests are nonlinguistic and highly correlated with speech identification performance. However, they are generally not amenable to clinical environments as they typically require the use of computers which are often not found in clinic sound booths. In this study, we evaluate the Spectral-temporally Modulated Ripple Test (SMRT) Lite for computeRless Measurement (SLRM), which is a new variant of the adaptive SMRT that can be implemented via a CD player. SMRT and SLRM were measured for 10 normal hearing and 10 cochlear implant participants. Performance on the two tests was highly correlated (r = 0.97). The results suggest that SLRM can be used interchangeably with SMRT but can be implemented without a computer.

Moderate Reverberation Does Not Increase Subjective Fatigue, Subjective Listening Effort, or Behavioral Listening Effort in School-Aged Children.

Background noise and reverberation levels in typical classrooms have negative effects on speech recognition, but their effects on listening effort and fatigue are less well understood. Based on the Framework for Understanding Effortful Listening, noise and reverberation would be expected to increase both listening effort and fatigue. However, previous investigations of the effects of reverberation for adults have resulted in mixed findings. Some discrepancies in the literature might be accounted for by methodological differences; behavioral and subjective indices of listening effort do not often align in adults. The effects of sustained listening on self-reported fatigue in school-aged children are also not well understood. The purposes of this project were to (1) evaluate the effects of noise and reverberation on listening effort in school-aged children using behavioral and subjective measures, (2) compare subjective and behavioral indices of listening effort, and (3) evaluate the effects of reverberation on self-reported fatigue. Twenty typically developing children (10–17 years old) participated. Participants completed dual-task testing in two rooms that varied in terms of reverberation, an audiometric sound booth and a moderately reverberant room. In each room, testing was completed in quiet and in two levels of background noise. Participants provided subjective ratings of listening effort after completing the dual-task in each listening condition. Subjective ratings of fatigue were completed before and after testing in each level of reverberation. Results revealed background noise, not reverberation, increased behavioral and subjective listening effort. Subjective ratings of perceived performance, ease of listening, and desire to control the listening situation revealed a similar pattern of results as word recognition performance, making them poor candidates for providing an indication of behavioral listening effort. However, ratings of time perception were moderately correlated with behavioral listening effort. Finally, sustained listening for approximately 25 min increased self-reported fatigue, although changes in fatigue were comparable in low and moderately reverberant environments. In total, these data offer no evidence that a moderate level of reverberation increases listening effort or fatigue, but the data do support the reduction of background noise in classrooms.

Development and evaluation of a tablet-based diagnostic audiometer

Objective: To develop and evaluate a software application capable of conducting Pure-Tone Audiometry tests in clinical practice.Design: We designed and developed a mobile software application for iPad devices that performs Pure-Tone Audiometry according to ANSI and IEC standards. The application is proposed to be operated by a trained audiologist inside a sound booth. No extra equipment is required. Hence, it updates the procedure by showing the versatility of the proposed system. Particularly, it provides manual and automated measurement, including air- and bone-conduction audiometry.Study sample: Twenty-nine participants-patients of Papageorgiou Hospital, Thessaloniki, Greece were tested, with all degrees of hearing sensitivity. Manual air- and bone-conduction Pure-Tone Audiometry was conducted inside a sound booth. Participants were tested with conventional audiometry and the audiometric application, in order to validate the tablet-based audiometer for measuring hearing thresholds.Results: The majority (90.9%) of air-conduction estimated hearing thresholds and (90.8%) of air-bone gaps were within 5 dB, compared to results obtained by conventional audiometry. Thus, threshold differences were not significant.Conclusions: The proposed audiometer is a reliable and valid tool for hearing assessment. Owing to certain limitations, mobile devices can provide a feasible substitute for conventional audiometry in clinical practice.

The Effects of Nonlinear Frequency Compression and Digital Noise Reduction on Word Recognition and Satisfaction Ratings in Noise in Adult Hearing Aid Users.

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. The effects of NLFC and DNR in noise on word recognition and satisfaction ratings in noise in adult hearing aid users were evaluated. A repeated measures design was used. 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. 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. 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. 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.

Adult validation of a self-administered tablet audiometer

BackgroundThere is evidence to suggest that rates of hearing loss are increasing more rapidly than the capacity of traditional audiometry resources for screening. A novel innovation in tablet, self-administered portable audiometry has been proposed as a solution to this discordance. The primary objective of this study was to validate a tablet audiometer with adult patients in a clinical setting. Secondarily, word recognition with a tablet audiometer was compared against conventional audiometry.MethodsThree distinct prospective adult cohorts underwent testing. In group 1 and group 2 testing with the automated tablet audiometer was compared to standard sound booth audiometry. In Group 1, participants’ pure tone thresholds were measured with an automated tablet audiometer in a quiet clinic exam room. In Group 2, participants completed monosyllabic word recognition testing using the NU-6 word lists. In Group 3, internal reliability was tested by having participants perform two automated tablet audiometric evaluation in sequence.ResultsGroup 1 included 40 patients mean age was 54.7 ± 18.4 years old and 60% female; Group 2 included 44 participants mean age was 55.2 ± 14.8 years old and 68.2% female; Group 3 included 40 participants with mean age of 39.4 + 15.9 years old and 60.5% female. In Group 1, compared to standard audiometry, 95.7% (95% CI: 92.6–98.9%) of thresholds were within 10 dB. In Group 2, comparing word recognition results, 96.2% (95% CI: 89.5–98.7%) were clinically equivalent and within a critical difference range. In Group 3, One-way Intraclass Correlation for agreement for the both left- and right-ear pure tone average was 0.98. The mean difference between repeat assessments was 0 (SD = 2.1) in the left ear, and 0.1 (SD = 1.1) in the right ear.ConclusionPuretone audiometry and word recognition testing appears valid when performed by non-healthcare experts using a tablet audiometer outside a sound booth in a quiet environment.Trial registrationClinicalTrials.gov Identifier: NCT02761798.Registered April, 2016 < https://clinicaltrials.gov/ct2/show/NCT02761798>

Reproducibility of Voice Parameters: The Effect of Room Acoustics and Microphones

Computer analysis of voice recordings is an integral part of the evaluation and management of voice disorders. In many practices, voice samples are taken in rooms that are not sound attenuated and/or sound-proofed; further, the technology used is rarely consistent. This will likely affect the recordings, and therefore, their analyses. The objective of this study is to compare various acoustic outcome measures taken from samples recorded in a sound-proofed booth to those recorded in more common clinic environments. Further, the effects from six different commonly used microphones will be compared. Thirty-six speakers were recorded while reading a text and producing sustained vowels in a controlled acoustic environment. The collected samples were reproduced by a Head and Torso Simulator and recorded in three clinical rooms and in a sound booth using six different microphones. Newer measures (eg, Pitch Strength, cepstral peak prominence, Acoustic Voice Quality Index), as well as more traditional measures (eg Jitter, Shimmer, harmonics-to-noise ratio and Spectrum Tilt), were calculated from the samples collected with each microphone and within each room. The measures which are more robust to room acoustic differences, background noise, and microphone quality include Jitter and smooth cepstral peak prominence, followed by Shimmer, Acoustic Voice Quality Index, harmonics-to-noise ratio, Pitch Strength, and Spectrum Tilt. The effect of room acoustics and background noise on voice parameters appears to be stronger than the type of microphone used for the recording. Consequently, an appropriate acoustical clinical space may be more important than the quality of the microphone.

Using Microphone Technology to Improve Speech Perception in Noise in Children with Cochlear Implants.

Cochlear implant (CI) users are affected more than their normal hearing (NH) peers by the negative consequences of background noise on speech understanding. Research has shown that adult CI users can improve their speech recognition in challenging listening environments by using dual-microphone beamformers, such as adaptive directional microphones (ADMs) and wireless remote microphones (RMs). The suitability of these microphone technologies for use in children with CIs is not well-understood nor widely accepted. To assess the benefit of ADM or RM technology on speech perception in background noise in children and adolescents with cochlear implants (CIs) with no previous or current use of ADM or RM. Mixed, repeated measures design. Twenty (20) children, ten (10) CI users (mean age 14.3 yrs) who used Advanced Bionics HiRes90K implants with research Naida processors, and ten (10) NH age-matched controls participated in this prospective study. CI users listened with an ear-canal level microphone, T-Mic (TM), an ADM, and a wireless RM at different audio-mixing ratios. Speech understanding with five microphone settings (TM 100%, ADM, RM + TM 50/50, RM + TM 75/25, RM 100%) was evaluated in quiet and in noise. Speech perception ability was measured using children's spondee words to obtain a speech recognition threshold for 80% accuracy (SRT80%) in 20-talker babble where the listener sat in a sound booth 1 m (3.28') from the target speech (front) and noise (behind) to test five microphone settings (TM 100%, ADM, RM + TM 50/50, RM + TM 75/25, RM 100%). Group performance-intensity functions were computed for each listening condition to show the effects of microphone configuration with respect to signal-to-noise ratio (SNR). A difference score (CI Group minus NH Group) was computed to show the effect of microphone technology at different SNRs relative to NH. Statistical analysis using a repeated-measures analysis of variance evaluated the effects of the microphone configurations on SRT80% and performance at SNRs. Between-groups analysis of variance was used to compare the CI group with the NH group. The speech recognition was significantly poorer for children with CI than children with NH in quiet and in noise when using the TM alone. Adding the ADM or RM provided a significant improvement in speech recognition for the CI group over use of the TM alone in noise (mean dB advantage ranged from 5.8 for ADM to 16 for RM100). When children with CI used the RM75 or RM100 in background babble, speech recognition was not statistically different from the group with NH. Speech recognition in noise performance improved with the use of ADM and RM100 or RM75 over TM-only for children with CIs. Alhough children with CI remain at a disadvantage as compared with NH children in quiet and more favorable SNRs, microphone technology can enhance performance for some children with CI to match that of NH peers in contexts with negative SNRs.