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Convery E.,ing Cooperative Research Center | Convery E.,Macquarie University | Keidser G.,ing Cooperative Research Center | Seeto M.,ing Cooperative Research Center | And 2 more authors.
Journal of the American Academy of Audiology | Year: 2015

Background: A reliable and valid method for the automatic in situ measurement of hearing thresholds is a prerequisite for the feasibility of a self-fitting hearing aid, whether such a device becomes an automated component of an audiological management program or is fitted by the user independently of a clinician. Issues that must be addressed before implementation of the procedure into a self-fitting hearing aid include the role of real-ear-to-dial difference correction factors in ensuring accurate results and the ability of potential users to successfully self-direct the procedure. Purpose: The purpose of this study was to evaluate the reliability and validity of an automatic audiometry algorithm that is fully implemented in a wearable hearing aid, to determine to what extent reliability and validity are affected when the procedure is self-directed by the user, and to investigate contributors to a successful outcome. Research Design: Design was a two-phase correlational study. Study Sample: A total of 60 adults with mild to moderately severe hearing loss participated in both studies: 20 in Study 1 and 40 in Study 2. Twenty-seven participants in Study 2 attended with a partner. Participants in both phases were selected for inclusion if their thresholds were within the output limitations of the test device. Data Collection and Analysis: In both phases, participants performed automatic audiometry through a receiver-in-canal, behind-the-ear hearing aid coupled to an open dome. In Study 1, the experimenter directed the task. In Study 2, participants followed a set of written, illustrated instructions to perform automatic audiometry independently of the experimenter, with optional assistance from a lay partner. Standardized measures of hearing aid self-efficacy, locus of control, cognitive function, health literacy, and manual dexterity were administered. Statistical analysis examined the repeatability of automatic audiometry; the match between automatically and manually measured thresholds; and contributors to successful, independent completion of the automatic audiometry procedure. Results: When the procedure was directed by an audiologist, automatic audiometry yielded reliable and valid thresholds. Reliability and validity were negatively affected when the procedure was self-directed by the user, but the results were still clinically acceptable: test-retest correspondence was 10 dB or lower in 97% of cases, and 91% of automatic thresholds were within 10 dB of their manual counterparts. However, only 58% of participants were able to achieve a complete audiogram in both ears. Cognitive function significantly influenced accurate and independent performance of the automatic audiometry procedure; accuracy was further affected by locus of control and level of education. Several characteristics of the automatic audiometry algorithm played an additional role in the outcome. Conclusions: Average transducer- and coupling-specific correction factors are sufficient for a self-directed in situ audiometry procedure to yield clinically reliable and valid hearing thresholds. Before implementation in a self-fitting hearing aid, however, the algorithm and test instructions should be refined in an effort to increase the proportion of users who are able to achieve complete audiometric results. Further evaluation of the procedure, particularly among populations likely to form the primary audience of a self-fitting hearing aid, should be undertaken.

Dahl H.-H.,Murdoch Childrens Research Institute | Dahl H.-H.,University of Melbourne | Ching T.Y.C.,National Acoustic Laboratories | Ching T.Y.C.,ing Cooperative Research Center | And 7 more authors.
PLoS ONE | Year: 2013

Hearing loss is an etiologically heterogeneous trait with differences in the age of onset, severity and site of lesion. It is caused by a combination of genetic and/or environmental factors. A longitudinal study to examine the efficacy of early intervention for improving child outcomes is ongoing in Australia. To determine the cause of hearing loss in these children we undertook molecular testing of perinatal "Guthrie" blood spots of children whose hearing loss was either detected via newborn hearing screening or detected later in infancy. We analyzed the GJB2 and SLC26A4 genes for the presence of mutations, screened for the mitochondrial DNA (mtDNA) A1555G mutation, and screened for congenital CMV infection in DNA isolated from dried newborn blood spots. Results were obtained from 364 children. We established etiology for 60% of children. One or two known GJB2 mutations were present in 82 children. Twenty-four children had one or two known SLC26A4 mutations. GJB2 or SLC26A4 changes with unknown consequences on hearing were found in 32 children. The A1555G mutation was found in one child, and CMV infection was detected in 28 children. Auditory neuropathy spectrum disorder was confirmed in 26 children whose DNA evaluations were negative. A secondary objective was to investigate the relationship between etiology and audiological outcomes over the first 3 years of life. Regression analysis was used to investigate the relationship between hearing levels and etiology. Data analysis does not support the existence of differential effects of etiology on degree of hearing loss or on progressiveness of hearing loss. © 2013 Dahl et al.

Glyde H.,ing Cooperative Research Center | Glyde H.,National Acoustic Laboratories | Glyde H.,University of Queensland | Cameron S.,ing Cooperative Research Center | And 7 more authors.
Ear and Hearing | Year: 2013

OBJECTIVES: Difficulty in understanding speech in background noise is frequently reported by hearing-impaired people despite well-fitted amplification. Understanding speech in the presence of background noise involves segregating the various auditory stimuli into distinct streams using cues such as pitch characteristics, spatial location of speakers, and contextual information. One possible cause of listening difficulties in noise is reduced spatial-processing ability. Previous attempts to investigate spatial processing in hearing-impaired people have often been confounded by inadequate stimulus audibility. The present research aimed to investigate the effects of hearing impairment and aging on spatial-processing ability. The effect of cognitive ability on spatial processing was also explored. In addition, the relationship between spatial-processing ability and self-report measures of listening difficulty was examined to investigate how much effect spatial-processing ability has in real-world situations. DESIGN: Eighty participants aged between 7 and 89 years took part in the study. Participants' hearing thresholds ranged from within normal limits to a moderately severe sensorineural hearing loss. All participants had English as their first language and no reported learning disabilities. The study sample included both hearing aid users and non-hearing aid users. Spatial-processing ability was assessed with a modified version of the Listening in Spatialized Noise-Sentences test (LiSN-S). The LiSN-S was modified to incorporate a prescribed gain amplifier that amplified the target and distracting stimulus according to the National Acoustic Laboratories-Revised Profound (NAL-RP) prescription. In addition, participants aged 18 years and above completed the Neurobehavioral Cognitive Status examination and the Speech, Spatial and Qualities questionnaire. Participants aged under 18 years completed the Listening Inventory for Education questionnaire. RESULTS: Spatial-processing ability, as measured by the spatial advantage measure of the LiSN-S, was negatively affected by hearing impairment. Aging was not significantly correlated with spatial-processing ability. No significant relationship was found between cognitive ability and spatial processing. Self-reported listening difficulty in children, as measured with the Listening Inventory for Education, and spatial-processing ability were not correlated. Self-reported listening difficulty in adults, as measured by the Speech, Spatial and Qualities questionnaire, was significantly correlated with spatial-processing ability. CONCLUSIONS: All hearing-impaired people will have a spatial processing deficit of some degree. This should be given due consideration when counseling patients in regard to realistic expectations of how they will perform in background noise. Further research is required into potential remediation for spatial-processing deficits and the cause of these deficits. Copyright © 2012 by Lippincott Williams & Wilkins.

Dawson P.W.,ing Cooperative Research Center | Dawson P.W.,Cochlear Limited | Mauger S.J.,ing Cooperative Research Center | Hersbach A.A.,Cochlear Limited
Ear and Hearing | Year: 2011

OBJECTIVE:: The aim of this study was to investigate whether a real-time noise reduction algorithm provided speech perception benefit for Cochlear™ Nucleus® cochlear implant recipients in the laboratory. Design: The noise reduction algorithm attenuated masker-dominated channels. It estimated the signal-to-noise ratio of each channel on a short-term basis from a single microphone input, using a recursive minimum statistics method. In this clinical evaluation, the algorithm was implemented in two programs (noise reduction programs 1 [NR1] and 2 [NR2]), which differed in their level of noise reduction. These programs used advanced combination encoder (ACE™) channel selection and were compared with ACE without noise reduction in 13 experienced cochlear implant subjects. An adaptive speech reception threshold (SRT) test provided the signal-to-noise ratio for 50% sentence intelligibility in three different types of noises: speech-weighted, cocktail party, and street-side city noise. Results: In all three noise types, mean SRTs for both NR programs were significantly better than those for ACE. The greatest improvement occurred for speech-weighted noise; the SRT benefit over ACE was 1.77 dB for NR1 and 2.14 dB for NR2. There were no significant differences in speech perception scores between the two NR programs. Subjects reported no degradation in sound quality with the experimental programs. Conclusions: The noise reduction algorithm was successful in improving sentence perception in speech-weighted noise, as well as in more dynamic types of background noise. The algorithm is currently being trialed in a behind-the-ear processor for take-home use. © 2011 Lippincott Williams & Wilkins, Inc.

Wang S.,Capital Medical University | Wang S.,Macquarie University | Wang S.,ing Cooperative Research Center | Xu L.,Ohio University | And 2 more authors.
JARO - Journal of the Association for Research in Otolaryngology | Year: 2011

It has been reported that normal-hearing Chinese speakers base their lexical tone recognition on fine structure regardless of temporal envelope cues. However, a few psychoacoustic and perceptual studies have demonstrated that listeners with sensorineural hearing impairment may have an impaired ability to use fine structure information, whereas their ability to use temporal envelope information is close to normal. The purpose of this study is to investigate the relative contributions of temporal envelope and fine structure cues to lexical tone recognition in normal-hearing and hearing-impaired native Mandarin Chinese speakers. Twenty-two normal-hearing subjects and 31 subjects with various degrees of sensorineural hearing loss participated in the study. Sixteen sets of Mandarin monosyllables with four tone patterns for each were processed through a "chimeric synthesizer" in which temporal envelope from a monosyllabic word of one tone was paired with fine structure from the same monosyllable of other tones. The chimeric tokens were generated in the three channel conditions (4, 8, and 16 channels). Results showed that differences in tone responses among the three channel conditions were minor. On average, 90.9%, 70.9%, 57.5%, and 38.2% of tone responses were consistent with fine structure for normal-hearing, moderate, moderate to severe, and severely hearing-impaired groups respectively, whereas 6.8%, 21.1%, 31.4%, and 44.7% of tone responses were consistent with temporal envelope cues for the above-mentioned groups. Tone responses that were consistent neither with temporal envelope nor fine structure had averages of 2.3%, 8.0%, 11.1%, and 17.1% for the above-mentioned groups of subjects. Pure-tone average thresholds were negatively correlated with tone responses that were consistent with fine structure, but were positively correlated with tone responses that were based on the temporal envelope cues. Consistent with the idea that the spectral resolvability is responsible for fine structure coding, these results demonstrated that, as hearing loss becomes more severe, lexical tone recognition relies increasingly on temporal envelope rather than fine structure cues due to the widened auditory filters. © 2011 Association for Research in Otolaryngology.

Tomlin D.,ing Cooperative Research Center | Tomlin D.,University of Melbourne | Dillon H.,ing Cooperative Research Center | Dillon H.,National Acoustic Laboratories | And 3 more authors.
Ear and Hearing | Year: 2015

To examine the links between auditory processing (AP) test results, functional deficits, and cognitive abilities. Design: One hundred and fifty-five children, ages 7-12 years, comprising 50 control children and 105 children referred for AP assessment, all with normal peripheral hearing, completed an AP and cognitive (sustained attention, auditory working memory, and nonverbal intelligence) test battery. Functional outcome measures of listening ability (developed using questionnaires from parent, teacher, and child respondents) and reading fluency were also collected. Results: AP scores for dichotic digits, frequency pattern, and listening in spatialized noise-sentences test baseline scores showed significant intertask correlations, and significant correlations with functional outcomes. The gaps in noise task showed correlation with reading fluency only. The AP tasks of masking level differences and spatial advantage showed no correlation with listening ability or reading fluency. Results showed significantly poorer cognitive abilities overall in the children referred for AP assessment compared with the control group. Within the referred group, children diagnosed with an auditory processing disorder had significantly poorer cognitive abilities than those passing the test battery. Correlation and regression studies showed significant associations between AP and cognitive scores. The results of multilinear regression analyses showed that the associations of AP scores with listening and academic results were no longer significant when cognitive scores were also included as predictors. Conclusions: A complex interaction of cognitive abilities and AP scores is evident. For many children with listening difficulties, who perform poorly on AP tasks, cognitive deficits are also in place. Although the direction of causality is unclear, it is likely that these cognitive deficits are causing the perceived difficulty and/or are having a significant effect on the test results. Interpretation of AP tests requires consideration of how cognitive abilities may have impacted on not only task results but also the functional difficulties experienced by the child. © 2015 Wolters Kluwer Health, Inc.

Boisvert I.,Macquarie University | Boisvert I.,ing Cooperative Research Center | Boisvert I.,Kimab - Corrosion And Metals Research Institute | McMahon C.M.,Macquarie University | And 4 more authors.
Ear and Hearing | Year: 2011

OBJECTIVES: Making evidence-based recommendations to prospective unilateral cochlear implant recipients on the potential benefits of implanting one or the other ear is challenging for cochlear implant teams. This particularly occurs in cases where a hearing aid has only been used in one ear for many years (referred to here as the "hearing ear"), and the contralateral ear has, in essence, been sound-deprived. In such cases, research to date is inconclusive, and little anecdotal evidence exists to inform the debate and support best clinical practice. DESIGN: Retrospective data on speech recognition outcomes of 16 adult participants who received a cochlear implant in an ear deprived of sound for a minimum of 15 yr were analyzed. All subjects were implanted through the Quebec Cochlear Implant Program and were provided with personalized intensive rehabilitation services. Data obtained from clinical records included demographic data and speech recognition scores measured after implantation with the sentences of a multimedia auditory test battery in the auditory-only condition. Speech recognition outcomes were compared with the duration of auditory deprivation in the implanted ear, bilateral significant hearing loss, and auditory stimulation before bilateral significant hearing loss. RESULTS: Using nonparametric correlation analyses, a strong negative correlation was demonstrated between speech recognition scores and the duration of bilateral significant hearing loss and with the duration of auditory stimulation before bilateral significant hearing loss. No significant correlation with the duration of auditory deprivation or with the duration of prior auditory stimulation in the implanted ear was found. CONCLUSIONS: These findings suggest that functional outcomes of cochlear implantation for unilateral sound deprivation may be more strongly influenced by central processes than peripheral effects stemming from the deprivation per se. This indicates the relevance of considering the client's history of binaural hearing rather than the hearing in each ear individually when discussing possible outcomes with a cochlear implant. Copyright © 2011 by Lippincott Williams & Wilkins.

PubMed | ing Cooperative Research Center and University of Queensland
Type: | Journal: International journal of language & communication disorders | Year: 2016

Conversational breakdowns are a persistent concern for older adults with hearing impairment (HI). Previous studies in experimental settings have investigated potential causes of breakdowns in conversations with a person with HI, and effective strategies for repairing these breakdowns. However, little research has explored the causes of hearing-related communication breakdowns, and their repairs, in extended, naturally occurring conversations in a healthcare setting.To analyse systematically instances of clients initiations of repair within video-recorded initial audiology appointments, and to examine the interactional environment in which they occurred.Participants included 26 audiologists and their older adult clients (aged 55+ years). Companions were present in 17 of the 63 appointments. Conversation analysis (CA) was used to examine the video-recorded audiology appointments with older adults with HI. The corpus was systematically analysed for all instances of other-initiated repair by clients (initiation of repair targeting the prior speakers turn). A collection of 51 instances of other-initiated repair were identified. These instances were analysed in detail for: (1) the interactional environment in which they occurred; (2) the strategy by which the client initiated repair; and (3) the strategies used by the audiologist to repair the communication breakdown.In 76% (n = 39) of the 51 cases of other-initiated repair from the client, there was a lack of mutual gaze between participants (i.e., either the audiologist or the client were looking away or facing in another direction during the prior turn). More specifically, many of these instances occurred when the audiologist was speaking to the client while multitasking. Audiologists used multiple-repair strategies in their responsive turn in an attempt to repair the communication breakdown efficiently.These findings, from extended, naturally occurring conversations with older adults with HI in clinic settings, highlight the importance of face-to-face communication even in quiet one-to-one settings. Clinicians should remain aware of their movements and gaze when speaking to clients during appointments. The findings also provide further support for the importance of communication programs in hearing rehabilitation.

Dawson P.W.,ing Cooperative Research Center | Dawson P.W.,Cochlear Limited | Hersbach A.A.,Cochlear Limited | Swanson B.A.,Cochlear Limited
Ear and Hearing | Year: 2013

Objectives: The aim of this research is to describe the development of an adaptive Australian Sentence Test in Noise and to validate the test in terms of test-retest reliability and efficiency using data obtained from its clinical application. Design: The relative intelligibility of 1264 Bamford-Kowal-Bench (BKB)-like sentences in the presence of competing four-talker babble was assessed with cochlear implant recipients. Intensity adjustments to the babble segments were made to reduce intersentence variability. Computer software was developed to administer an adaptive speech reception threshold (SRT) test using these adjusted sentence/babble pairs and test-retest SRT data from a separate group of 23 cochlear implant recipients was analyzed, comparing different SRT calculation and test stopping rules. Results: The adjusted sentence/babble pairs were used in clinical studies to obtain an SRT by presenting 32 sentences. Analysis of test-retest pairs of SRT data from 23 recipients indicated that a psychometric fit SRT calculation rule provided better reliability than did the Hearing in Noise Test (HINT) calculation rule, or rules based on mean turns. This rule, using the morpheme correct scores for each sentence, gave a standard deviation for a single SRT of 0.76 dB. Further analyses revealed that the test could be shortened to 20 sentences with an increase of 0.19 dB in variability, while reducing the median test time by approximately 2 min. Conclusions: This article reports validation data for a new Australian Sentence Test In Noise. When 20 BKB-like sentences are used with a psychometric fit calculation rule, a standard deviation of approximately 1 dB is obtained in approximately 3 min 36 sec. © 2013 by Lippincott Williams and Wilkins.

Bhattacharya A.,University of California at Irvine | Vandali A.,ing Cooperative Research Center | Zeng F.-G.,University of California at Irvine
Journal of the Acoustical Society of America | Year: 2011

The present study examined the effect of combined spectral and temporal enhancement on speech recognition by cochlear-implant (CI) users in quiet and in noise. The spectral enhancement was achieved by expanding the short-term Fourier amplitudes in the input signal. Additionally, a variation of the Transient Emphasis Spectral Maxima (TESM) strategy was applied to enhance the short-duration consonant cues that are otherwise suppressed when processed with spectral expansion. Nine CI users were tested on phoneme recognition tasks and ten CI users were tested on sentence recognition tasks both in quiet and in steady, speech-spectrum-shaped noise. Vowel and consonant recognition in noise were significantly improved with spectral expansion combined with TESM. Sentence recognition improved with both spectral expansion and spectral expansion combined with TESM. The amount of improvement varied with individual CI users. Overall the present results suggest that customized processing is needed to optimize performance according to not only individual users but also listening conditions. © 2011 Acoustical Society of America.

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