Fast, Continuous Audiogram Estimation Using Machine Learning.
Song, Xinyu D.; Wallace, Brittany M.; Gardner, Jacob R.; Ledbetter, Noah M.; Weinberger, Kilian Q.; Barbour, Dennis L., 2015-06-24 08:00:00 AM
Objectives: Pure-tone audiometry has been a staple of hearing assessments for decades. Many different procedures have been proposed for measuring thresholds with pure tones by systematically manipulating intensity one frequency at a time until a discrete threshold function is determined. The authors have developed a novel nonparametric approach for estimating a continuous threshold audiogram using Bayesian estimation and machine learning classification. The objective of this study was to assess the accuracy and reliability of this new method relative to a commonly used threshold measurement technique. Design: The authors performed air conduction pure-tone audiometry on 21 participants between the ages of 18 and 90 years with varying degrees of hearing ability. Two repetitions of automated machine learning audiogram estimation and one repetition of conventional modified Hughson-Westlake ascending-descending audiogram estimation were acquired by an audiologist. The estimated hearing thresholds of these two techniques were compared at standard audiogram frequencies (i.e., 0.25, 0.5, 1, 2, 4, 8 kHz). Results: The two threshold estimate methods delivered very similar estimates at standard audiogram frequencies. Specifically, the mean absolute difference between estimates was 4.16 +/- 3.76 dB HL. The mean absolute difference between repeated measurements of the new machine learning procedure was 4.51 +/- 4.45 dB HL. These values compare favorably with those of other threshold audiogram estimation procedures. Furthermore, the machine learning method generated threshold estimates from significantly fewer samples than the modified Hughson-Westlake procedure while returning a continuous threshold estimate as a function of frequency. Conclusions: The new machine learning audiogram estimation technique produces continuous threshold audiogram estimates accurately, reliably, and efficiently, making it a strong candidate for widespread application in clinical and research audiometry. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Statistical Learning, Syllable Processing, and Speech Production in Healthy Hearing and Hearing-Impaired Preschool Children: A Mismatch Negativity Study.
Studer-Eichenberger, Esther; Studer-Eichenberger, Felix; Koenig, Thomas, 2015-06-24 08:00:00 AM
Objectives: The objectives of the present study were to investigate temporal/spectral sound-feature processing in preschool children (4 to 7 years old) with peripheral hearing loss compared with age-matched controls. The results verified the presence of statistical learning, which was diminished in children with hearing impairments (HIs), and elucidated possible perceptual mediators of speech production. Design: Perception and production of the syllables /ba/, /da/, /ta/, and /na/ were recorded in 13 children with normal hearing and 13 children with HI. Perception was assessed physiologically through event-related potentials (ERPs) recorded by EEG in a multifeature mismatch negativity paradigm and behaviorally through a discrimination task. Temporal and spectral features of the ERPs during speech perception were analyzed, and speech production was quantitatively evaluated using speech motor maximum performance tasks. Results: Proximal to stimulus onset, children with HI displayed a difference in map topography, indicating diminished statistical learning. In later ERP components, children with HI exhibited reduced amplitudes in the N2 and early parts of the late disciminative negativity components specifically, which are associated with temporal and spectral control mechanisms. Abnormalities of speech perception were only subtly reflected in speech production, as the lone difference found in speech production studies was a mild delay in regulating speech intensity. Conclusions: In addition to previously reported deficits of sound-feature discriminations, the present study results reflect diminished statistical learning in children with HI, which plays an early and important, but so far neglected, role in phonological processing. Furthermore, the lack of corresponding behavioral abnormalities in speech production implies that impaired perceptual capacities do not necessarily translate into productive deficits. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.The Effect of Functional Hearing and Hearing Aid Usage on Verbal Reasoning in a Large Community-Dwelling Population.
Keidser, Gitte; Rudner, Mary; Seeto, Mark; Hygge, Staffan; Rönnberg, Jerker, 2015-06-24 08:00:00 AM
Objectives: Verbal reasoning performance is an indicator of the ability to think constructively in everyday life and relies on both crystallized and fluid intelligence. This study aimed to determine the effect of functional hearing on verbal reasoning when controlling for age, gender, and education. In addition, the study investigated whether hearing aid usage mitigated the effect and examined different routes from hearing to verbal reasoning. Design: Cross-sectional data on 40- to 70-year-old community-dwelling participants from the UK Biobank resource were accessed. Data consisted of behavioral and subjective measures of functional hearing, assessments of numerical and linguistic verbal reasoning, measures of executive function, and demographic and lifestyle information. Data on 119,093 participants who had completed hearing and verbal reasoning tests were submitted to multiple regression analyses, and data on 61,688 of these participants, who had completed additional cognitive tests and provided relevant lifestyle information, were submitted to structural equation modeling. Results: Poorer performance on the behavioral measure of functional hearing was significantly associated with poorer verbal reasoning in both the numerical and linguistic domains (p < 0.001). There was no association between the subjective measure of functional hearing and verbal reasoning. Functional hearing significantly interacted with education (p < 0.002), showing a trend for functional hearing to have a greater impact on verbal reasoning among those with a higher level of formal education. Among those with poor hearing, hearing aid usage had a significant positive, but not necessarily causal, effect on both numerical and linguistic verbal reasoning (p < 0.005). The estimated effect of hearing aid usage was less than the effect of poor functional hearing. Structural equation modeling analyses confirmed that controlling for education reduced the effect of functional hearing on verbal reasoning and showed that controlling for executive function eliminated the effect. However, when computer usage was controlled for, the eliminating effect of executive function was weakened. Conclusions: Poor functional hearing was associated with poor verbal reasoning in a 40- to 70-year-old community-dwelling population after controlling for age, gender, and education. The effect of functional hearing on verbal reasoning was significantly reduced among hearing aid users and completely overcome by good executive function skills, which may be enhanced by playing computer games. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Masking Period Patterns and Forward Masking for Speech-Shaped Noise: Age-Related Effects.
Grose, John H.; Menezes, Denise C.; Porter, Heather L.; Griz, Silvana, 2015-06-24 08:00:00 AM
Objective: The purpose of this study was to assess age-related changes in temporal resolution in listeners with relatively normal audiograms. The hypothesis was that increased susceptibility to nonsimultaneous masking contributes to the hearing difficulties experienced by older listeners in complex fluctuating backgrounds. Design: Participants included younger (n = 11), middle-age (n = 12), and older (n = 11) listeners with relatively normal audiograms. The first phase of the study measured masking period patterns for speech-shaped noise maskers and signals. From these data, temporal window shapes were derived. The second phase measured forward-masking functions and assessed how well the temporal window fits accounted for these data. Results: The masking period patterns demonstrated increased susceptibility to backward masking in the older listeners, compatible with a more symmetric temporal window in this group. The forward-masking functions exhibited an age-related decline in recovery to baseline thresholds, and there was also an increase in the variability of the temporal window fits to these data. Conclusions: This study demonstrated an age-related increase in susceptibility to nonsimultaneous masking, supporting the hypothesis that exacerbated nonsimultaneous masking contributes to age-related difficulties understanding speech in fluctuating noise. Further support for this hypothesis comes from limited speech-in-noise data, suggesting an association between susceptibility to forward masking and speech understanding in modulated noise. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Development of Open-Set Word Recognition in Children: Speech-Shaped Noise and Two-Talker Speech Maskers.
Corbin, Nicole E.; Bonino, Angela Yarnell; Buss, Emily; Leibold, Lori J., 2015-06-24 08:00:00 AM
Objective: The goal of this study was to establish the developmental trajectories for children's open-set recognition of monosyllabic words in each of two maskers: two-talker speech and speech-shaped noise. Design: Listeners were 56 children (5 to 16 years) and 16 adults, all with normal hearing. Thresholds for 50% correct recognition of monosyllabic words were measured in a two-talker speech or a speech-shaped noise masker in the sound field using an open-set task. Target words were presented at a fixed level of 65 dB SPL throughout testing, while the masker level was adapted. A repeated-measures design was used to compare the performance of three age groups of children (5 to 7 years, 8 to 12 years, and 13 to 16 years) and a group of adults. The pattern of age-related changes during childhood was also compared between the two masker conditions. Results: Listeners in all four age groups performed more poorly in the two-talker speech than the speech-shaped noise masker, but the developmental trajectories differed for the two masker conditions. For the speech-shaped noise masker, children's performance improved with age until about 10 years of age, with little systematic child-adult differences thereafter. In contrast, for the two-talker speech masker, children's thresholds gradually improved between 5 and 13 years of age, followed by an abrupt improvement in performance to adult-like levels. Children's thresholds in the two masker conditions were uncorrelated. Conclusions: Younger children require a more advantageous signal-to-noise ratio than older children and adults to achieve 50% correct word recognition in both masker conditions. However, children's ability to recognize words appears to take longer to mature and follows a different developmental trajectory for the two-talker speech masker than the speech-shaped noise masker. These findings highlight the importance of considering both age and masker type when evaluating children's masked speech perception abilities. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Evaluation of Speech-Evoked Envelope Following Responses as an Objective Aided Outcome Measure: Effect of Stimulus Level, Bandwidth, and Amplification in Adults With Hearing Loss.
Easwar, Vijayalakshmi; Purcell, David W.; Aiken, Steven J.; Parsa, Vijay; Scollie, Susan D., 2015-06-24 08:00:00 AM
Objectives: The present study evaluated a novel test paradigm based on speech-evoked envelope following responses (EFRs) as an objective aided outcome measure for individuals fitted with hearing aids. Although intended for use in infants with hearing loss, this study evaluated the paradigm in adults with hearing loss, as a precursor to further evaluation in infants. The test stimulus was a naturally male-spoken token /susa[integral]i/, modified to enable recording of eight individual EFRs, two from each vowel for different formants and one from each fricative. In experiment I, sensitivity of the paradigm to changes in audibility due to varying stimulus level and use of hearing aids was tested. In experiment II, sensitivity of the paradigm to changes in aided audible bandwidth was evaluated. As well, experiment II aimed to test convergent validity of the EFR paradigm by comparing the effect of bandwidth on EFRs and behavioral outcome measures of hearing aid fitting. Design: Twenty-one adult hearing aid users with mild to moderately severe sensorineural hearing loss participated in the study. To evaluate the effects of level and amplification in experiment I, the stimulus was presented at 50 and 65 dB SPL through an ER-2 insert earphone in unaided conditions and through individually verified hearing aids in aided conditions. Behavioral thresholds of EFR carriers were obtained using an ER-2 insert earphone to estimate sensation level of EFR carriers. To evaluate the effect of aided audible bandwidth in experiment II, EFRs were elicited by /susa[integral]i/ low-pass filtered at 1, 2, and 4 kHz and presented through the programmed hearing aid. EFRs recorded in the 65 dB SPL aided condition in experiment I represented the full bandwidth condition. EEG was recorded from the vertex to the nape of the neck over 300 sweeps. Speech discrimination using the University of Western Ontario Distinctive Feature Differences test and sound quality rating using the Multiple-Stimulus Hidden Reference and Anchor paradigm were measured in the same bandwidth conditions. Results: In experiment I, an increase in stimulus level above threshold and the use of amplification resulted in a significant increase in the number of EFRs detected per condition. At positive sensation levels, an increase in level demonstrated a significant increase in response amplitude in unaided and aided conditions. At 50 and 65 dB SPL, the use of amplification led to a significant increase in response amplitude for the majority of carriers. In experiment II, the number of EFR detections and the combined response amplitude of all eight EFRs improved with an increase in bandwidth up to 4 kHz. In contrast, behavioral measures continued to improve at wider bandwidths. Further change in EFR parameters was possibly limited by the hearing aid bandwidth. Significant positive correlations were found between EFR parameters and behavioral test scores in experiment II. Conclusions: The EFR paradigm demonstrates sensitivity to changes in audibility due to a change in stimulus level, bandwidth, and use of amplification in clinically feasible test times. The paradigm may thus have potential applications as an objective aided outcome measure. Further investigations exploring stimulus-response relationships in aided conditions and validation studies in children are warranted. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Effect of Stimulus Level and Bandwidth on Speech-Evoked Envelope Following Responses in Adults With Normal Hearing.
Easwar, Vijayalakshmi; Purcell, David W.; Aiken, Steven J.; Parsa, Vijay; Scollie, Susan D., 2015-06-24 08:00:00 AM
Objective: The use of auditory evoked potentials as an objective outcome measure in infants fitted with hearing aids has gained interest in recent years. This article proposes a test paradigm using speech-evoked envelope following responses (EFRs) for use as an objective-aided outcome measure. The method uses a running speech-like, naturally spoken stimulus token /susa[Latin small letter esh]i/ (fundamental frequency [f0] = 98 Hz; duration 2.05 sec), to elicit EFRs by eight carriers representing low, mid, and high frequencies. Each vowel elicited two EFRs simultaneously, one from the region of formant one (F1) and one from the higher formants region (F2+). The simultaneous recording of two EFRs was enabled by lowering f0 in the region of F1 alone. Fricatives were amplitude modulated to enable recording of EFRs from high-frequency spectral regions. The present study aimed to evaluate the effect of level and bandwidth on speech-evoked EFRs in adults with normal hearing. As well, the study aimed to test convergent validity of the EFR paradigm by comparing it with changes in behavioral tasks due to bandwidth. Design: Single-channel electroencephalogram was recorded from the vertex to the nape of the neck over 300 sweeps in two polarities from 20 young adults with normal hearing. To evaluate the effects of level in experiment I, EFRs were recorded at test levels of 50 and 65 dB SPL. To evaluate the effects of bandwidth in experiment II, EFRs were elicited by /susa[Latin small letter esh]i/ low-pass filtered at 1, 2, and 4 kHz, presented at 65 dB SPL. The 65 dB SPL condition from experiment I represented the full bandwidth condition. EFRs were averaged across the two polarities and estimated using a Fourier analyzer. An F test was used to determine whether an EFR was detected. Speech discrimination using the University of Western Ontario Distinctive Feature Differences test and sound quality rating using the Multiple Stimulus Hidden Reference and Anchors paradigm were measured in identical bandwidth conditions. Results: In experiment I, the increase in level resulted in a significant increase in response amplitudes for all eight carriers (mean increase of 14 to 50 nV) and the number of detections (mean increase of 1.4 detections). In experiment II, an increase in bandwidth resulted in a significant increase in the number of EFRs detected until the low-pass filtered 4 kHz condition and carrier-specific changes in response amplitude until the full bandwidth condition. Scores in both behavioral tasks increased with bandwidth up to the full bandwidth condition. The number of detections and composite amplitude (sum of all eight EFR amplitudes) significantly correlated with changes in behavioral test scores. Conclusions: Results suggest that the EFR paradigm is sensitive to changes in level and audible bandwidth. This may be a useful tool as an objective-aided outcome measure considering its running speech-like stimulus, representation of spectral regions important for speech understanding, level and bandwidth sensitivity, and clinically feasible test times. This paradigm requires further validation in individuals with hearing loss, with and without hearing aids. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Nonmuscle Myosin Heavy Chain IIA Mutation Predicts Severity and Progression of Sensorineural Hearing Loss in Patients With MYH9-Related Disease.
Verver, Eva J. J.; Topsakal, Vedat; Kunst, Henricus P. M.; Huygen, Patrick L. M.; Heller, Paula G.; Pujol-Moix, Nuria; Savoia, Anna; Benazzo, Marco; Fierro, Tiziana; Grolman, Wilko; Gresele, Paolo; Pecci, Alessandro, 2015-06-24 08:00:00 AM
Objectives: MYH9-related disease (MYH9-RD) is an autosomal--dominant disorder deriving from mutations in MYH9, the gene for the nonmuscle myosin heavy chain (NMMHC)-IIA. MYH9-RD has a complex phenotype including congenital features, such as thrombocytopenia, and noncongenital manifestations, namely sensorineural hearing loss (SNHL), nephropathy, cataract, and liver abnormalities. The disease is caused by a limited number of mutations affecting different regions of the NMMHC-IIA protein. SNHL is the most frequent noncongenital manifestation of MYH9-RD. However, only scarce and anecdotal information is currently available about the clinical and audiometric features of SNHL of MYH9-RD subjects. The objective of this study was to investigate the severity and propensity for progression of SNHL in a large series of MYH9-RD patients in relation to the causative NMMHC-IIA mutations. Design: This study included the consecutive patients diagnosed with MYH9-RD between July 2007 and March 2012 at four participating institutions. A total of 115 audiograms were analyzed from 63 patients belonging to 45 unrelated families with different NMMHC-IIA mutations. Cross-sectional analyses of audiograms were performed. Regression analysis was performed, and age-related typical audiograms (ARTAs) were derived to characterize the type of SNHL associated with different mutations. Results: Severity of SNHL appeared to depend on the specific NMMHC-IIA mutation. Patients carrying substitutions at the residue R702 located in the short functional SH1 helix had the most severe degree of SNHL, whereas patients with the p.E1841K substitution in the coiled-coil region or mutations at the nonhelical tailpiece presented a mild degree of SNHL even at advanced age. The authors also disclosed the effects of different amino acid changes at the same residue: for instance, individuals with the p.R702C mutation had more severe SNHL than those with the p.R702H mutation, and the p.R1165L substitution was associated with a higher degree of hearing loss than the p.R1165C. In general, mild SNHL was associated with a fairly flat audiogram configuration, whereas severe SNHL correlated with downsloping configurations. ARTA plots showed that the most progressive type of SNHL was associated with the p.R702C, the p.R702H, and the p.R1165L substitutions, whereas the p.R1165C mutation correlated with a milder, nonprogressive type of SNHL than the p.R1165L. ARTA for the p.E1841K mutation demonstrated a mild degree of SNHL with only mild progression, whereas the ARTA for the mutations at the nonhelical tailpiece did not show any substantial progression. Conclusions: These data provide useful tools to predict the progression and the expected degree of severity of SNHL in individual MYH9-RD patients, which is especially relevant in young patients. Consequences in clinical practice are important not only for appropriate patient counseling but also for development of customized, genotype-driven clinical management. The authors recently reported that cochlear implantation has a good outcome in MYH9-RD patients; thus, stricter follow-up and earlier intervention are recommended for patients with unfavorable genotypes. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Background Noise Degrades Central Auditory Processing in Toddlers.
Niemitalo-Haapola, Elina; Haapala, Sini; Jansson-Verkasalo, Eira; Kujala, Teija, 2015-06-24 08:00:00 AM
Objectives: Noise, as an unwanted sound, has become one of modern society's environmental conundrums, and many children are exposed to higher noise levels than previously assumed. However, the effects of background noise on central auditory processing of toddlers, who are still acquiring language skills, have so far not been determined. The authors evaluated the effects of background noise on toddlers' speech-sound processing by recording event-related brain potentials. The hypothesis was that background noise modulates neural speech-sound encoding and degrades speech-sound discrimination. Design: Obligatory P1 and N2 responses for standard syllables and the mismatch negativity (MMN) response for five different syllable deviants presented in a linguistic multifeature paradigm were recorded in silent and background noise conditions. The participants were 18 typically developing 22- to 26-month-old monolingual children with healthy ears. Results: The results showed that the P1 amplitude was smaller and the N2 amplitude larger in the noisy conditions compared with the silent conditions. In the noisy condition, the MMN was absent for the intensity and vowel changes and diminished for the consonant, frequency, and vowel duration changes embedded in speech syllables. Furthermore, the frontal MMN component was attenuated in the noisy condition. However, noise had no effect on P1, N2, or MMN latencies. Conclusions: The results from this study suggest multiple effects of background noise on the central auditory processing of toddlers. It modulates the early stages of sound encoding and dampens neural discrimination vital for accurate speech perception. These results imply that speech processing of toddlers, who may spend long periods of daytime in noisy conditions, is vulnerable to background noise. In noisy conditions, toddlers' neural representations of some speech sounds might be weakened. Thus, special attention should be paid to acoustic conditions and background noise levels in children's daily environments, like day-care centers, to ensure a propitious setting for linguistic development. In addition, the evaluation and improvement of daily listening conditions should be an ordinary part of clinical intervention of children with linguistic problems. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Clinical Outcomes for Adult Cochlear Implant Recipients Experiencing Loss of Usable Acoustic Hearing in the Implanted Ear: Erratum: Changes to the Editorial Board and New Guidelines for Reporting Population-Based Research: Erratum.
2015-06-24 08:00:00 AM
Vestibular, Visual Acuity, and Balance Outcomes in Children With Cochlear Implants: A Preliminary Report.
Janky, Kristen L.; Givens, Diane, 2015-06-24 08:00:00 AM
Objectives: There is a high incidence of vestibular loss in children with cochlear implants (CCI). However, the relationship between vestibular loss and various outcomes is unknown in children. The objectives of this study are to (1) determine if age-related changes in peripheral vestibular tests occur; (2) quantify peripheral vestibular function in children with normal hearing and CCI; (3) determine if amount of vestibular loss predicts visual acuity and balance performance. Design: Eleven CCI and 12 children with normal hearing completed the following tests of vestibular function: ocular and cervical vestibular-evoked myogenic potential to assess utricle and saccule function and the video head impulse test to assess semicircular canal function. The relationship between amount of vestibular loss and the following balance and visual acuity outcomes was assessed: dynamic gait index, single-leg stance, the sensory organization test, and tests of visual acuity, including dynamic visual acuity and the gaze stabilization test. Results: (1) There were no significant age-related changes in peripheral vestibular testing with the exception of the n23 cervical vestibular-evoked myogenic potential latency, which was moderately correlated with age. (2) CCI had significantly higher rates of vestibular loss for each test of canal and otolith function. (3) Amount of vestibular loss predicted performance on single-leg stance, the dynamic gait index, some conditions of the sensory organization test, and the dynamic visual acuity test. Age was also a contributing factor for predicting the performance of almost all outcomes. Conclusions: Preliminarily, children with vestibular loss do not recover naturally to levels of their healthy peers, particularly with activities that utilize vestibular input; they have poorer visual acuity and balance function. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Effects of Aging on the Encoding of Dynamic and Static Components of Speech.
Presacco, Alessandro; Jenkins, Kimberly; Lieberman, Rachel; Anderson, Samira, 2015-06-24 08:00:00 AM
Objectives: The authors investigated aging effects on the envelope of the frequency following response to dynamic and static components of speech. Older adults frequently experience problems understanding speech, despite having clinically normal hearing. Improving audibility with hearing aids provides variable benefit, as amplification cannot restore the temporal precision degraded by aging. Previous studies have demonstrated age-related delays in subcortical timing specific to the dynamic, transition region of the stimulus. However, it is unknown whether this delay is mainly due to a failure to encode rapid changes in the formant transition because of central temporal processing deficits or as a result of cochlear damage that reduces audibility for the high-frequency components of the speech syllable. To investigate the nature of this delay, the authors compared subcortical responses in younger and older adults with normal hearing to the speech syllables /da/ and /a/, hypothesizing that the delays in peak timing observed in older adults are mainly caused by temporal processing deficits in the central auditory system. Design: The frequency following response was recorded to the speech syllables /da/ and /a/ from 15 younger and 15 older adults with normal hearing, normal IQ, and no history of neurological disorders. Both speech syllables were presented binaurally with alternating polarities at 80 dB SPL at a rate of 4.3 Hz through electromagnetically shielded insert earphones. A vertical montage of four Ag-AgCl electrodes (Cz, active, forehead ground, and earlobe references) was used. Results: The responses of older adults were significantly delayed with respect to younger adults for the transition and onset regions of the /da/ syllable and for the onset of the /a/ syllable. However, in contrast with the younger adults who had earlier latencies for /da/ than for /a/ (as was expected given the high-frequency energy in the /da/ stop consonant burst), latencies in older adults were not significantly different between the responses to /da/ and /a/. An unexpected finding was noted in the amplitude and phase dissimilarities between the two groups in the later part of the steady-state region, rather than in the transition region. This amplitude reduction may indicate prolonged neural recovery or response decay associated with a loss of auditory nerve fibers. Conclusions: These results suggest that older adults' peak timing delays may arise from decreased synchronization to the onset of the stimulus due to reduced audibility, though the possible role of impaired central auditory processing cannot be ruled out. Conversely, a deterioration in temporal processing mechanisms in the auditory nerve, brainstem, or midbrain may be a factor in the sudden loss of synchronization in the later part of the steady-state response in older adults. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Self-Reported Hearing Difficulties Among Adults With Normal Audiograms: The Beaver Dam Offspring Study.
Tremblay, Kelly L.; Pinto, Alex; Fischer, Mary E.; Klein, Barbara E. K.; Klein, Ronald; Levy, Sarah; Tweed, Ted S.; Cruickshanks, Karen J., 2015-06-24 08:00:00 AM
Objective: Clinicians encounter patients who report experiencing hearing difficulty (HD) even when audiometric thresholds fall within normal limits. When there is no evidence of audiometric hearing loss, it generates debate over possible biomedical and psychosocial etiologies. It is possible that self-reported HDs relate to variables within and/or outside the scope of audiology. The purpose of this study is to identify how often, on a population basis, people with normal audiometric thresholds self-report HD and to identify factors associated with such HDs. Design: This was a cross-sectional investigation of participants in the Beaver Dam Offspring Study. HD was defined as a self-reported HD on a four-item scale despite having pure-tone audiometric thresholds within normal limits (<20 dB HL0.5, 1, 2, 3, 4, 6, 8 kHz bilaterally, at each frequency). Distortion product otoacoustic emissions and word-recognition performance in quiet and with competing messages were also analyzed. In addition to hearing assessments, relevant factors such as sociodemographic and lifestyle factors, environmental exposures, medical history, health-related quality of life, and symptoms of neurological disorders were also examined as possible risk factors. The Center for Epidemiological Studies-Depression was used to probe symptoms associated with depression, and the Medical Outcomes Study Short-Form 36 mental score was used to quantify psychological stress and social and role disability due to emotional problems. The Visual Function Questionnaire-25 and contrast sensitivity test were used to query vision difficulties. Results: Of the 2783 participants, 686 participants had normal audiometric thresholds. An additional grouping variable was created based on the available scores of HD (four self-report questions), which reduced the total dataset to n = 682 (age range, 21-67 years). The percentage of individuals with normal audiometric thresholds who self-reported HD was 12.0% (82 of 682). The prevalence in the entire cohort was therefore 2.9% (82 of 2783). Performance on audiological tests (distortion product otoacoustic emissions and word-recognition tests) did not differ between the group self-reporting HD and the group reporting no HD. A multivariable model controlling for age and sex identified the following risk factors for HD: lower incomes (odds ratio [OR] $50,000+ = 0.55, 95% confidence interval [CI] = 0.30-1.00), noise exposure through loud hobbies (OR = 1.48, 95% CI = 1.15-1.90), or firearms (OR = 2.07, 95% CI = 1.04-4.16). People reporting HD were more likely to have seen a doctor for hearing loss (OR = 12.93, 95% CI = 3.86-43.33) and report symptoms associated with depression (Center for Epidemiological Studies-Depression [OR = 2.39, 95% CI = 1.03-5.54]), vision difficulties (Visual Function Questionnaire-25 [OR = 0.93, 95% CI = 0.89-0.97]), and neuropathy (e.g., numbness, tingling, and loss of sensation [OR = 1.98, 95% CI = 1.14-3.44]). Conclusions: The authors used a population approach to identify the prevalence and risk factors associated with self-reported HD among people who perform within normal limits on common clinical tests of auditory function. The percentage of individuals with normal audiometric thresholds who self-reported HD was 12.0%, resulting in an overall prevalence of 2.9%. Auditory and nonauditory risk factors were identified, therefore suggesting that future directions aimed at assessing, preventing, and managing these types of HDs might benefit from information outside the traditional scope of audiology. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Electrophysiology and Perception of Speech in Noise in Older Listeners: Effects of Hearing Impairment and Age.
Billings, Curtis J.; Penman, Tina M.; McMillan, Garnett P.; Ellis, Emily M., 2015-06-24 08:00:00 AM
Objectives: Speech perception in background noise is difficult for many individuals, and there is considerable performance variability across listeners. The combination of physiological and behavioral measures may help to understand sources of this variability for individuals and groups and prove useful clinically with hard-to-test populations. The purpose of this study was threefold: (1) determine the effect of signal-to-noise ratio (SNR) and signal level on cortical auditory evoked potentials (CAEPs) and sentence-level perception in older normal-hearing (ONH) and older hearing-impaired (OHI) individuals, (2) determine the effects of hearing impairment and age on CAEPs and perception, and (3) explore how well CAEPs correlate with and predict speech perception in noise. Design: Two groups of older participants (15 ONH and 15 OHI) were tested using speech-in-noise stimuli to measure CAEPs and sentence-level perception of speech. The syllable /ba/, used to evoke CAEPs, and sentences were presented in speech-spectrum background noise at four signal levels (50, 60, 70, and 80 dB SPL) and up to seven SNRs (-10, -5, 0, 5, 15, 25, and 35 dB). These data were compared between groups to reveal the hearing impairment effect and then combined with previously published data for 15 young normal-hearing individuals to determine the aging effect. Results: Robust effects of SNR were found for perception and CAEPs. Small but significant effects of signal level were found for perception, primarily at poor SNRs and high signal levels, and in some limited instances for CAEPs. Significant effects of age were seen for both CAEPs and perception, while hearing impairment effects were only found with perception measures. CAEPs correlate well with perception and can predict SNR50s to within 2 dB for ONH. However, prediction error is much larger for OHI and varies widely (from 6 to 12 dB) depending on the model that was used for prediction. Conclusions: When background noise is present, SNR dominates both perception-in-noise testing and cortical electrophysiological testing, with smaller and sometimes significant contributions from signal level. A mismatch between behavioral and electrophysiological results was found (hearing impairment effects were primarily only seen for behavioral data), illustrating the possible contributions of higher order cognitive processes on behavior. It is interesting that the hearing impairment effect size was more than five times larger than the aging effect size for CAEPs and perception. Sentence-level perception can be predicted well in normal-hearing individuals; however, additional research is needed to explore improved prediction methods for older individuals with hearing impairment. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.The Effect of Increasing Intracranial Pressure on Ocular Vestibular-Evoked Myogenic Potential Frequency Tuning.
Jerin, Claudia; Wakili, Reza; Kalla, Roger; Gürkov, Robert, 2015-06-24 08:00:00 AM
Objective: Ocular vestibular-evoked myogenic potentials (oVEMPs) represent extraocular muscle activity in response to vestibular stimulation. The authors sought to investigate whether posture-induced increase of the intracranial pressure (ICP) modulated oVEMP frequency tuning, that is, the amplitude ratio between 500-Hz and 1000-Hz stimuli. Design: Ten healthy subjects were enrolled in this study. The subjects were positioned in the horizontal plane (0 degree) and in a 30-degree head-downwards position to elevate the ICP. In both positions, oVEMPs were recorded using 500-Hz and 1000-Hz air-conducted tone bursts. Results: When tilting the subject from the horizontal plane to the 30-degree head-down position, oVEMP amplitudes in response to 500-Hz tone bursts distinctly decreased (3.40 [mu]V versus 2.06 [mu]V; p < 0.001), whereas amplitudes to 1000 Hz were only slightly diminished (2.74 [mu]V versus 2.48 [mu]V; p = 0.251). Correspondingly, the 500/1000-Hz amplitude ratio significantly decreased when tilting the subjects from 0- to 30-degree inclination (1.59 versus 1.05; p = 0.029). Latencies were not modulated by head-down position. Conclusions: Increasing ICP systematically alters oVEMPs in terms of absolute amplitudes and frequency tuning characteristics. oVEMPs are therefore in principle suited for noninvasive ICP monitoring. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Changes in Tinnitus After Middle Ear Implant Surgery: Comparisons With the Cochlear Implant.
Seo, Young Joon; Kim, Hyun Ji; Moon, In Seok; Choi, Jae Young, 2015-06-24 08:00:00 AM
Objectives: Tinnitus is a very common symptom in patients with hearing loss. Several studies have confirmed that hearing restoration using hearing aids or cochlear implants (CIs) has a suppressive effect on tinnitus in users. The aim of this study was to analyze the effect of other hearing restoration devices, specifically the middle ear implant (MEI), on changes in tinnitus severity. Design: From 2012 to October 2014, 11 adults with tinnitus and hearing loss underwent MEI surgery. Pure-tone audiometry, tinnitus handicap inventory (THI), and visual analog scale scores for loudness, awareness, and annoyance and psychosocial instruments were measured before, immediately after, and 6 months after surgery. Changes in hearing thresholds and THI scores were analyzed and compared with those of 16 CI recipients. Results: In both MEI and CI groups, significant improvements in tinnitus were found after the surgery. The THI scores improved in 91% of patients in the MEI group and in 56% of those in the CI group. Visual analog scale scores and psychosocial scale scores also decreased after surgery, but there were no statistical differences between the groups. Conclusions: The results indicate that the MEI may be as beneficial as the CI in relieving tinnitus in subjects with unilateral tinnitus accompanying hearing loss. Furthermore, this improvement may manifest as hearing restoration or habituation rather than a direct electrical nerve stimulation, which was previously considered as the main mechanism underlying tinnitus suppression by auditory implants. This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Negative Middle Ear Pressure and Composite and Component Distortion Product Otoacoustic Emissions.
Thompson, Suzanne; Henin, Simon; Long, Glenis R., 2015-06-24 08:00:00 AM
Objectives: Distortion product otoacoustic emissions (DPOAEs), a by-product of normal outer hair cell function, are used in research and clinical settings to noninvasively test cochlear health. The composite DPOAE recorded in the ear canal is the result of interactions of at least two components: a nonlinear distortion component (the generator component) and a linear reflection component. Negative middle ear pressure (NMEP) results in the tympanic membrane being pulled inward and increases middle ear impedance. This influences both the forward travel of stimuli used to induce distortion products and the reverse travel of the emissions back to the ear canal. NMEP may therefore limit the effectiveness of DPOAEs in clinical settings. Design: Twenty-six normal-hearing subjects were recruited, and eight were able to reliably and consistently induce NMEP using the Toynbee maneuver. Eight interleaved measures of tympanic peak pressure (TPP) were collected for each subject at normal pressure and NMEP. DPOAEs were then collected both when middle ear pressure was normal and during subject-induced NMEP. All measures were interleaved. Two primary tones were swept logarithmically across frequency (1 second per octave) from f1 = 410 to 6560 Hz and f2 = 500 to 8000 Hz (f1/f2 = 1.22), producing 2f1 - f2 DPOAEs from 320 to 5120 Hz. DPOAEs were collected at three equal-level primary level combinations (L65, L70, L75 dB SPL). Before composite and component DPOAE analysis, analysis of the f1 DPOAE primary confirmed that subjects had successfully induced NMEP. DPOAE and component magnitudes were separately analyzed using repeated measures analysis of variances with three factors, primary level (L65, L70, L75 dB SPL), middle ear pressure (normal pressure versus NMEP), and frequency (500 to 4000 Hz). Results: Mean subject-induced NMEP ranged from -65 to -324 daPa. Changes in the magnitude (dB) of the primary tones used to induce the DPOAE provided a reliable indicator of subject-induced NMEP. Composite DPOAE and component levels were significantly affected by NMEP for all the frequencies tested. Changes were most clearly observed for the generator component with one subject demonstrating a mean decrease of 12 dB in magnitude during NMEP. Results were subject-specific, and there was a correlation between the degree of negative TPP induced and the amount of change in DPOAE level. Conclusions: Mean TPPs collected during NMEP ranged from -65 to -324 daPa and significantly affected composite DPOAE, generator, and reflection component levels. Changes in the magnitude of the swept-primaries as a function of frequency were used to confirm that NMEP had been successfully induced. The patterns of change in the composite DPOAEs were clearer and easier to interpret when the components of the DPOAE were separated with evaluation of the generator component alone. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Bigger Is Better: Increasing Cortical Auditory Response Amplitude Via Stimulus Spectral Complexity.
Bardy, Fabrice; Van Dun, Bram; Dillon, Harvey, 2015-06-24 08:00:00 AM
Objective: To determine the influence of auditory stimuli spectral characteristics on cortical auditory evoked potentials (CAEPs). Design: CAEPs were obtained from 15 normal-hearing adults in response to six multitone (MT), four pure-tone (PT), and two narrowband noise stimuli. The sounds were presented at 10, 20, and 40 dB above threshold, which were estimated behaviorally beforehand. The root mean square amplitude of the CAEP and the detectability of the response were calculated and analyzed. Results: Amplitudes of the CAEPs to the MT were significantly larger compared with PT for stimuli with frequencies centered around 1, 2, and 4 kHz, whereas no significant difference was found for 0.5 kHz. The objective detection score for the MT was significantly higher compared with the PT. For the 1- and 2-kHz stimuli, the CAEP amplitudes to narrowband noise were not significantly different than those evoked by PT. Conclusion: The study supports the notion that spectral complexity, not just bandwidth, has an impact on the CAEP amplitude for stimuli with center frequency above 0.5 kHz. The implication of these findings is that the clinical test time required to estimate thresholds can potentially be decreased by using complex band-limited MT rather than conventional PT stimuli. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Auditory Perception and Production of Speech Feature Contrasts by Pediatric Implant Users.
Mahshie, James; Core, Cynthia; Larsen, Michael D., 2015-06-24 08:00:00 AM
Objective: The aim of the present research is to examine the relations between auditory perception and production of specific speech contrasts by children with cochlear implants (CIs) who received their implants before 3 years of age and to examine the hierarchy of abilities for perception and production for consonant and vowel features. The following features were examined: vowel height, vowel place, consonant place of articulation (front and back), continuance, and consonant voicing. Design: Fifteen children (mean age = 4;0 and range 3;2 to 5;11) with a minimum of 18 months of experience with their implants and no additional known disabilities served as participants. Perception of feature contrasts was assessed using a modification of the Online Imitative Speech Pattern Contrast test, which uses imitation to assess speech feature perception. Production was examined by having the children name a series of pictures containing consonant and vowel segments that reflected contrasts of each feature. Results: For five of the six feature contrasts, production accuracy was higher than perception accuracy. There was also a significant and positive correlation between accuracy of production and auditory perception for each consonant feature. This correlation was not found for vowels, owing largely to the overall high perception and production scores attained on the vowel features. The children perceived vowel feature contrasts more accurately than consonant feature contrasts. On average, the children had lower perception scores for Back Place and Continuance feature contrasts than for Anterior Place and Voicing contrasts. For all features, the median production scores were 100%; the majority of the children were able to accurately and consistently produce the feature contrasts. The mean production scores for features reflect greater score variability for consonant feature production than for vowel features. Back Place of articulation for back consonants and Continuance contrasts appeared to be the most difficult features to produce, as reflected in lower mean production scores for these features. Conclusions: The finding of greater production than auditory perception accuracy for five of the six features examined suggests that the children with CIs were able to produce articulatory contrasts that were not readily perceived through audition alone. Factors that are likely to play a role in the greater production accuracy in addition to audition include the lexical and phonetic properties of the words elicited, a child's phonological representation of the words and motor abilities, and learning through oro-tactile, visual, proprioceptive, and kinesthetic perception. The differences among the features examined, and between perception and production, point to the clinical importance of evaluating these abilities in children with CIs. The present findings further point to the utility of picture naming to establish a child's production accuracy, which in turn is necessary if using imitation as a measure of auditory capacity. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Pediatric Cochlear Implantation: Why Do Children Receive Implants Late?.
Fitzpatrick, Elizabeth M.; Ham, Julia; Whittingham, JoAnne, 2015-06-24 08:00:00 AM
Objectives: Early cochlear implantation has been widely promoted for children who derive inadequate benefit from conventional acoustic amplification. Universal newborn hearing screening has led to earlier identification and intervention, including cochlear implantation in much of the world. The purpose of this study was to examine age and time to cochlear implantation and to understand the factors that affected late cochlear implantation in children who received cochlear implants. Design: In this population-based study, data were examined for all children who underwent cochlear implant surgery in one region of Canada from 2002 to 2013. Clinical characteristics were collected prospectively as part of a larger project examining outcomes from newborn hearing screening. For this study, audiologic details including age and severity of hearing loss at diagnosis, age at cochlear implant candidacy, and age at cochlear implantation were documented. Additional detailed medical chart information was extracted to identify the factors associated with late implantation for children who received cochlear implants more than 12 months after confirmation of hearing loss. Results: The median age of diagnosis of permanent hearing loss for 187 children was 12.6 (interquartile range: 5.5, 21.7) months, and the age of cochlear implantation over the 12-year period was highly variable with a median age of 36.2 (interquartile range: 21.4, 71.3) months. A total of 118 (63.1%) received their first implant more than 12 months after confirmation of hearing loss. Detailed analysis of clinical profiles for these 118 children revealed that late implantation could be accounted for primarily by progressive hearing loss (52.5%), complex medical conditions (16.9%), family indecision (9.3%), geographical location (5.9%), and other miscellaneous known (6.8%) and unknown factors (8.5%). Conclusions: This study confirms that despite the trend toward earlier implantation, a substantial number of children can be expected to receive their first cochlear implant well beyond their first birthday because they do not meet audiologic criteria of severe to profound hearing loss for cochlear implantation at the time of identification of permanent hearing loss. This study underscores the importance of carefully monitoring all children with permanent hearing loss to ensure that optimal intervention including cochlear implantation occurs in a timely manner. This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Social Support Predicts Hearing Aid Satisfaction.
Singh, Gurjit; Lau, Sin-Tung; Pichora-Fuller, M. Kathleen, 2015-06-24 08:00:00 AM
Objectives: The goals of the current research were to determine: (i) whether there is a relationship between perceived social support and hearing aid satisfaction, and (ii) how well perceived social support predicts hearing aid satisfaction relative to other correlates previously identified in the literature. Design: In study 1, 173 adult (x age = 68.9 years; SD = 13.4) users of hearing aids completed a survey assessing attitudes toward health, hearing, and hearing aids, as well as a questionnaire assessing Big-Five personality factors (Openness to Experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism) either using paper and pencil or the Internet. In a follow-up study designed to replicate and extend the results from study 1, 161 adult (x age = 32.8 years; SD = 13.3) users of hearing aids completed a similar survey on the Internet. In study 2, participants also completed a measure of hearing aid benefit and reported the style of their hearing aid. Results: In studies 1 and 2, perceived social support was significantly correlated with hearing aid satisfaction (respectively, r = 0.34, r = 0.51, ps < 0.001). The results of a regression analysis revealed that in study 1, 22% of the variance in hearing aid satisfaction scores was predicted by perceived social support, satisfaction with one's hearing health care provider, duration of daily hearing aid use, and openness. In study 2, 43% of the variance in hearing aid satisfaction was predicted by perceived social support, hearing aid benefit, neuroticism, and hearing aid style. Overall, perceived social support was the best predictor of hearing aid satisfaction in both studies. After controlling for response style (i.e., acquiescence or the tendency to respond positively), the correlation between perceived social support and hearing aid satisfaction remained the same in study 1 (r = 0.34, p < 0.001) and was lower in study 2 (r = 0.39, p < 0.001), although the change in correlation was not significant. Conclusions: The results from study 1 provide evidence to suggest that perceived social support is a significant predictor of satisfaction with hearing aids, a finding that was replicated in a different sample of participants investigated in study 2. A significant relationship between perceived social support and hearing aid satisfaction was observed in both studies, even though the composition of the two samples differed in terms of age, relationship status, income, proportion of individuals with unilateral versus bilateral hearing impairment, and lifetime experience with hearing aids. The results from both studies 1 and 2 provide no support for the claim that participant response style accounts for the relationship between hearing aid satisfaction and perceived social support. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Use of Questionnaire-Based Measures in the Assessment of Listening Difficulties in School-Aged Children.
Barry, Johanna G.; Tomlin, Danielle; Moore, David R.; Dillon, Harvey, 2015-06-24 08:00:00 AM
Objectives: In this study, the authors assessed the potential utility of a recently developed questionnaire (Evaluation of Children's Listening and Processing Skills [ECLiPS]) for supporting the clinical assessment of children referred for auditory processing disorder (APD). Design: A total of 49 children (35 referred for APD assessment and 14 from mainstream schools) were assessed for auditory processing (AP) abilities, cognitive abilities, and symptoms of listening difficulty. Four questionnaires were used to capture the symptoms of listening difficulty from the perspective of parents (ECLiPS and Fisher's auditory problem checklist), teachers (Teacher's Evaluation of Auditory Performance), and children, that is, self-report (Listening Inventory for Education). Correlation analyses tested for convergence between the questionnaires and both cognitive and AP measures. Discriminant analyses were performed to determine the best combination of tests for discriminating between typically developing children and children referred for APD. Results: All questionnaires were sensitive to the presence of difficulty, that is, children referred for assessment had significantly more symptoms of listening difficulty than typically developing children. There was, however, no evidence of more listening difficulty in children meeting the diagnostic criteria for APD. Some AP tests were significantly correlated with ECLiPS factors measuring related abilities providing evidence for construct validity. All questionnaires correlated to a greater or lesser extent with the cognitive measures in the study. Discriminant analysis suggested that the best discrimination between groups was achieved using a combination of ECLiPS factors, together with nonverbal Intelligence Quotient (cognitive) and AP measures (i.e., dichotic digits test and frequency pattern test). Conclusions: The ECLiPS was particularly sensitive to cognitive difficulties, an important aspect of many children referred for APD, as well as correlating with some AP measures. It can potentially support the preliminary assessment of children referred for APD. This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Speech Perception With Combined Electric-Acoustic Stimulation: A Simulation and Model Comparison.
Rader, Tobias; Adel, Youssef; Fastl, Hugo; Baumann, Uwe, 2015-06-24 08:00:00 AM
Objective: The aim of this study is to simulate speech perception with combined electric-acoustic stimulation (EAS), verify the advantage of combined stimulation in normal-hearing (NH) subjects, and then compare it with cochlear implant (CI) and EAS user results from the authors' previous study. Furthermore, an automatic speech recognition (ASR) system was built to examine the impact of low-frequency information and is proposed as an applied model to study different hypotheses of the combined-stimulation advantage. Signal-detection-theory (SDT) models were applied to assess predictions of subject performance without the need to assume any synergistic effects. Design: Speech perception was tested using a closed-set matrix test (Oldenburg sentence test), and its speech material was processed to simulate CI and EAS hearing. A total of 43 NH subjects and a customized ASR system were tested. CI hearing was simulated by an aurally adequate signal spectrum analysis and representation, the part-tone-time-pattern, which was vocoded at 12 center frequencies according to the MED-EL DUET speech processor. Residual acoustic hearing was simulated by low-pass (LP)-filtered speech with cutoff frequencies 200 and 500 Hz for NH subjects and in the range from 100 to 500 Hz for the ASR system. Speech reception thresholds were determined in amplitude-modulated noise and in pseudocontinuous noise. Previously proposed SDT models were lastly applied to predict NH subject performance with EAS simulations. Results: NH subjects tested with EAS simulations demonstrated the combined-stimulation advantage. Increasing the LP cutoff frequency from 200 to 500 Hz significantly improved speech reception thresholds in both noise conditions. In continuous noise, CI and EAS users showed generally better performance than NH subjects tested with simulations. In modulated noise, performance was comparable except for the EAS at cutoff frequency 500 Hz where NH subject performance was superior. The ASR system showed similar behavior to NH subjects despite a positive signal-to-noise ratio shift for both noise conditions, while demonstrating the synergistic effect for cutoff frequencies >=300 Hz. One SDT model largely predicted the combined-stimulation results in continuous noise, while falling short of predicting performance observed in modulated noise. Conclusions: The presented simulation was able to demonstrate the combined-stimulation advantage for NH subjects as observed in EAS users. Only NH subjects tested with EAS simulations were able to take advantage of the gap listening effect, while CI and EAS user performance was consistently degraded in modulated noise compared with performance in continuous noise. The application of ASR systems seems feasible to assess the impact of different signal processing strategies on speech perception with CI and EAS simulations. In continuous noise, SDT models were largely able to predict the performance gain without assuming any synergistic effects, but model amendments are required to explain the gap listening effect in modulated noise. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Relationship Among Signal Fidelity, Hearing Loss, and Working Memory for Digital Noise Suppression.
Arehart, Kathryn; Souza, Pamela; Kates, James; Lunner, Thomas; Pedersen, Michael Syskind, 2015-06-24 08:00:00 AM
Objectives: This study considered speech modified by additive babble combined with noise-suppression processing. The purpose was to determine the relative importance of the signal modifications, individual peripheral hearing loss, and individual cognitive capacity on speech intelligibility and speech quality. Design: The participant group consisted of 31 individuals with moderate high-frequency hearing loss ranging in age from 51 to 89 years (mean = 69.6 years). Speech intelligibility and speech quality were measured using low-context sentences presented in babble at several signal-to-noise ratios. Speech stimuli were processed with a binary mask noise-suppression strategy with systematic manipulations of two parameters (error rate and attenuation values). The cumulative effects of signal modification produced by babble and signal processing were quantified using an envelope-distortion metric. Working memory capacity was assessed with a reading span test. Analysis of variance was used to determine the effects of signal processing parameters on perceptual scores. Hierarchical linear modeling was used to determine the role of degree of hearing loss and working memory capacity in individual listener response to the processed noisy speech. The model also considered improvements in envelope fidelity caused by the binary mask and the degradations to envelope caused by error and noise. Results: The participants showed significant benefits in terms of intelligibility scores and quality ratings for noisy speech processed by the ideal binary mask noise-suppression strategy. This benefit was observed across a range of signal-to-noise ratios and persisted when up to a 30% error rate was introduced into the processing. Average intelligibility scores and average quality ratings were well predicted by an objective metric of envelope fidelity. Degree of hearing loss and working memory capacity were significant factors in explaining individual listener's intelligibility scores for binary mask processing applied to speech in babble. Degree of hearing loss and working memory capacity did not predict listeners' quality ratings. Conclusions: The results indicate that envelope fidelity is a primary factor in determining the combined effects of noise and binary mask processing for intelligibility and quality of speech presented in babble noise. Degree of hearing loss and working memory capacity are significant factors in explaining variability in listeners' speech intelligibility scores but not in quality ratings. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Bilateral Loudness Balancing and Distorted Spatial Perception in Recipients of Bilateral Cochlear Implants.
Fitzgerald, Matthew B.; Kan, Alan; Goupell, Matthew J., 2015-06-24 08:00:00 AM
Objective: To determine whether bilateral loudness balancing during mapping of bilateral cochlear implants (CIs) produces fused, punctate, and centered auditory images that facilitate lateralization with stimulation on single-electrode pairs. Design: Adopting procedures similar to those that are practiced clinically, direct stimulation was used to obtain most-comfortable levels (C levels) in recipients of bilateral CIs. Three pairs of electrodes, located in the base, middle, and apex of the electrode array, were tested. These electrode pairs were loudness-balanced by playing right-left electrode pairs sequentially. In experiment 1, the authors measured the location, number, and compactness of auditory images in 11 participants in a subjective fusion experiment. In experiment 2, the authors measured the location and number of the auditory images while imposing a range of interaural level differences (ILDs) in 13 participants in a lateralization experiment. Six of these participants repeated the mapping process and lateralization experiment over three separate days to determine the variability in the procedure. Results: In approximately 80% of instances, bilateral loudness balancing was achieved from relatively small adjustments to the C levels (<=3 clinical current units). More important, however, was the observation that in 4 of 11 participants, simultaneous bilateral stimulation regularly elicited percepts that were not fused into a single auditory object. Across all participants, approximately 23% of percepts were not perceived as fused; this contrasts with the 1 to 2% incidence of diplacusis observed with normal-hearing individuals. In addition to the unfused images, the perceived location was often offset from the physical ILD. On the whole, only 45% of percepts presented with an ILD of 0 clinical current units were perceived as fused and heard in the center of the head. Taken together, these results suggest that distortions to the spatial map remain common in bilateral CI recipients even after careful bilateral loudness balancing. Conclusions: The primary conclusion from these experiments is that, even after bilateral loudness balancing, bilateral CI recipients still regularly perceive stimuli that are unfused, offset from the assumed zero ILD, or both. Thus, while current clinical mapping procedures for bilateral CIs are sufficient to enable many of the benefits of bilateral hearing, they may not elicit percepts that are thought to be optimal for sound-source location. As a result, in the absence of new developments in signal processing for CIs, new mapping procedures may need to be developed for bilateral CI recipients to maximize the benefits of bilateral hearing. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Meta-Analysis of Distortion Product Otoacoustic Emission Retest Variability for Serial Monitoring of Cochlear Function in Adults.
Reavis, Kelly M.; McMillan, Garnett P.; Dille, Marilyn F.; Konrad-Martin, Dawn, 2015-06-24 08:00:00 AM
Objective: Distortion product otoacoustic emissions (DPOAEs) have long been heralded as a means to objectively monitor cochlear function and increasingly are becoming a key component in hearing surveillance programs for individuals at risk for ototoxic- and occupational noise-related hearing loss. Yet clinicians are unsure how to define clinically meaningful shifts in DPOAE level. In this study, a meta-analysis approach is used to synthesize the DPOAE level test-retest literature to construct a set of DPOAE level shift reference limits that can be used clinically to define a statistically significant emission change. Design: The authors reviewed all published articles identified through a Medline search using the terms "Otoacoustic Emission Variability," "Otoacoustic Emission Reliability," "Otoacoustic Emission Repeatability," and "Otoacoustic Emission Test Retest" restricted to DPOAEs, adults, and English language. Articles with DPOAE level data elicited by moderate stimulus levels for f2 frequencies of 1000, 2000, 4000, or 6000 Hz were selected because these stimulus parameters were relatively well represented in the literature. The authors only included articles that reported the standard error of the measurement (SEM) or from which the SEM could be calculated. Meta-analysis was used to estimate the population mean SEM over the included studies. Models were fit separately for each f2 primary and included days since baseline and study-specific random effects. Results: Ten DPOAE test-retest studies met inclusion criteria for this meta-analysis. The SEM values varied widely across published studies (0.57 to 3.9 dB) and were provided for relatively short time intervals (less than 15 days on average). Time, or days since baseline, was statistically significant at higher f2 frequencies (4000 and 6000 Hz). From the model results, 90% reference limits specific to the f2 and elapsed time between baseline and follow-up measurements were established. Reference limits provided correspond to negative (emission decrement) and positive (emission enhancement) shifts indicative of the amount of measurement variability that, using this approach, must be tolerated as "normal" fluctuations over time. Changes larger than the reference limits are considered significant and warrant follow-up testing. Conclusions: The meta-analysis presented provides reference limits that are appropriate for a set of specific f2 frequencies and time intervals. The meta-analysis concerns the SEM statistic directly, so that any preferred reference limit can be computed from the results and should be predicated upon the screening application. The presumed advantage of this meta-analytic approach is increased precision relative to limits suggested by any of the individual studies included in the analysis. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Satisfaction With Cochlear Implants in Postlingually Deaf Adults and Its Nonaudiological Predictors: Psychological Distress, Coping Strategies, and Self-Esteem.
Kobosko, Joanna; Jedrzejczak, W. Wiktor; Pilka, Edyta; Pankowska, Agnieszka; Skarzynski, Henryk, 2015-06-24 08:00:00 AM
Objective: A postlingually deaf patient who receives a cochlear implant (CI) acquires multiple benefits, not just audiological but also nonaudiological: improvement in quality of life, psychological well-being, and social interaction. The aim of the study was to ascertain the relationship between the CI satisfaction experienced by adult, postlingually deaf individuals and their level of psychological distress, stress coping strategies, and global self-esteem. We also considered sociodemographic variables (such as sex, age, education, marital/partner status, and employment/study status), variables related to their deafness, and their length of experience with a CI. Design: The study had a cross-sectional design in which participants were asked to fill in a mailed personal inquiry form seeking sociodemographic data and one question related to CI satisfaction, and the following questionnaires: General Health Questionnaire-28, the Brief Coping Orientation to Problems Experienced, and the Rosenberg Self-Esteem Scale. This study included 98 patients with postlingual deafness between 19 and 85 years old who had unilateral CIs. For some analyses, the patients were also divided into two groups: younger (<=60 years) and older (>60 years). Two other subgroups were those with shorter CI experience (1 to 2 years) and those with longer CI experience (5 to 6 years). As an objective reference, speech perception scores in quiet and in noise were also used. Results: The majority of postlingually deaf subjects rated their CI satisfaction as high or very high, and this was at similar levels in younger and older subjects, as well as in those who had used CIs for either a short or a long time. CI satisfaction was not related to speech perception scores, duration of deafness, length of CI use, or other sociodemographic factors. Positive self-esteem, having less severe symptoms of depression, and the use of humor or self-distraction were conducive to CI satisfaction. Using a coping strategy of denial had a negative association with CI satisfaction. Coping strategies and symptoms of mental distress varied between younger and older subjects. For younger subjects, higher CI satisfaction was associated with lower severity of depressive symptoms, whereas for the elderly, higher CI satisfaction was associated with less severe social dysfunction symptoms. Over the years of using a CI, the same strategy may have a different psychological function in providing satisfaction: for example, venting, which in the group with a short CI experience is negatively correlated to satisfaction, is positively correlated to satisfaction for those with longer CI experience. Conclusions: The results show that psychological factors-self-esteem, distress, and coping strategies-are important for CI satisfaction in postlingually deaf CI users. The results point to advantages in widening the availability of various tailored forms of psychological intervention for patients with postlingual deafness after receiving a CI. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Wideband Absorbance Outcomes in Newborns: A Comparison With High-Frequency Tympanometry, Automated Brainstem Response, and Transient Evoked and Distortion Product Otoacoustic Emissions.
Aithal, Sreedevi; Kei, Joseph; Driscoll, Carlie; Khan, Asaduzzaman; Swanston, Andrew, 2015-06-24 08:00:00 AM
Objectives: The purpose of this study was to evaluate the test performance of wideband absorbance (WBA) in terms of its ability to predict the outer and middle ear status as determined by nine reference standards. Design: Automated auditory brainstem response (AABR), high-frequency (1000 Hz) tympanometry (HFT), transient evoked otoacoustic emission (TEOAE), and distortion product otoacoustic emission (DPOAE) tests were performed on 298 ears (144 right, 154 left) of 192 (108 males, 84 females) neonates with a mean age of 43.7 hours (SD = 21.3, range = 8.3 to 152.2 hr). WBA was measured from 0.25 to 8 kHz using clicks under ambient pressure conditions. Test performance of WBA was assessed in terms of its ability to identify conductive conditions in neonates when compared with nine reference standards (including four single tests and five test batteries) using the receiver operating characteristic analysis. Results: The test performance of WBA against the test battery reference standards was better than that against single test reference standards. The area under the receiver operating characteristic curve reached a high value of 0.78 for HFT + TEOAE + DPOAE and AABR + TEOAE + DPOAE reference standards. Within the ears that passed each of the reference standards, there were no significant differences in WBA. However, for the ears that failed each of the test standards, there were significant differences in WBA. The region between 1 and 4 kHz provided the best discriminability to evaluate the conductive status compared with other frequencies. Conclusions: WBA is a desirable measure of conductive conditions in newborns due to its high performance in classifying ears with conductive loss as determined by the best performing surrogate gold standards (HFT + TEOAE + DPOAE and AABR + TEOAE + DPOAE). Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.The Impact of Auditory Processing and Cognitive Abilities in Children.
Tomlin, Dani; Dillon, Harvey; Sharma, Mridula; Rance, Gary, 2015-06-24 08:00:00 AM
Objectives: 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. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Effects of Nonlinear Frequency Compression on ACC Amplitude and Listener Performance.
Kirby, Benjamin James; Brown, Carolyn J., 2015-06-24 08:00:00 AM
Objectives: Nonlinear frequency compression is a signal processing technique used to increase the audibility of high-frequency speech sounds for hearing aid users with sloping, high-frequency hearing loss. However, excessive compression ratios may reduce spectral contrast between sounds and negatively impact speech perception. This is of particular concern in infants and young children who may not be able to provide feedback about frequency compression settings. This study explores the use of an objective cortical auditory evoked potential that is sensitive to changes in spectral contrast, the acoustic change complex (ACC), in the verification of frequency compression parameters. Design: ACC responses were recorded from adult listeners to a spectral ripple contrast stimulus that was processed using a range of frequency compression ratios (1:1, 1.5:1, 2:1, 3:1, and 4:1). Vowel identification, consonant identification, speech recognition in noise (QuickSIN), and behavioral ripple discrimination thresholds were also measured under identical frequency compression conditions. In Experiment 1, these tasks were completed in 10 adults with normal hearing. In Experiment 2, these same tasks were repeated in 10 adults with sloping, high-frequency hearing loss. Results: Repeated measures analysis of variance was completed for each task and each group with frequency compression ratio as the within-subjects factor. Increasing the compression ratio did not affect vowel identification for the normal hearing group but did cause a significant decrease in vowel identification for the hearing-impaired listeners. Increases in compression ratio were associated with significant decrements in ACC amplitudes, consonant identification scores, ripple discrimination thresholds, and speech perception in noise scores for both groups of listeners. Conclusions: The ACC response, like speech and nonspeech perceptual measures, is sensitive to frequency compression ratio. Additional study is needed to establish optimal stimulus and recording parameters for the clinical application of this measure in the verification of hearing aid frequency compression settings. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Hearing and Patient Satisfaction Among 19 Patients Who Received Implants Intended for Hybrid Hearing: A Two-Year Follow-Up.
Erixon, Elsa; Rask-Andersen, Helge, 2015-06-24 08:00:00 AM
Objectives: To measure patient satisfaction and correlate to hearing results in partially deaf patients, after hearing preservation cochlear implant surgery with hybrid hearing strategy, and to evaluate the stability of residual low-frequency hearing (LFH) over time. Design: A patient satisfaction survey and a retrospective, 2-year follow-up journal study. Nineteen partially deaf patients intended for hybrid hearing responded to a questionnaire when they had used their cochlear implants for at least a year. The questionnaire consisted of the International Outcome Inventory for Hearing Aids, EuroQol Group visual analogue scale and nine questions about hybrid hearing. Pure-tone audiometry, monosyllables, and hearing in noise test results from the patients' medical records were evaluated and compared with the results from the patient satisfaction survey. Results: All of the patients were satisfied with their CIs. The mean International Outcome Inventory for Hearing Aids score was 29. The CIs provided a major contribution to the speech comprehension of these partially deaf patients. Two years after surgery, the patients' mean binaural score on tests of monosyllables was 58%, and the mean signal to noise ratio was 4.6 dB. We observed ongoing deteriorations in the residual hearing of the operated ears that surpassed the deteriorations observed in the contralateral ears. One month after surgery, the LFH loss (125-500 Hz) was 17 dB, and after 2 years, this loss was 24 dB compared with 5 dB in the nonoperated ear. There were no significant correlations between preserved LFH and patient satisfaction or speech perception results. Conclusions: Electric stimulation provided a major contribution to speech comprehension of partially deaf patients. The gain reached in speech understanding widely exceeded the downside in losing some residual hearing. All the patients showed a high degree of satisfaction with their CIs regardless of varying hearing preservation. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Outcome Measurement in Adult Auditory Rehabilitation: A Scoping Review of Measures Used in Randomized Controlled Trials.
Barker, Fiona; MacKenzie, Emma; Elliott, Lynette; de Lusignan, Simon, 2015-06-24 08:00:00 AM
Objectives: This review documented the range and nature of reported outcome measures in the context of adult auditory rehabilitative research. Design: A scoping review conducted as a part of the development of a systematic review of the effect of interventions to improve hearing aid use. The authors searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials; PubMed; EMBASE; CINAHL; Web of Science; Cambridge Scientific Abstracts; ICTRP; and additional sources for published and unpublished randomized control trials. The date of the search was November 6, 2013. Outcomes were grouped using a framework suggested by the Cochrane Effective Practice and Organization of Care group. Results: Patient outcomes included adherence to hearing aid use, daily hours of aid use, hearing handicap, hearing aid benefit, quality of life, and communication and psychological outcome. Satisfaction and speech perception were frequent secondary outcomes. There was diversity in measures used to report patient outcomes. Outcome categories other than patient health status and behavior were rarely reported. The timing of outcome measurement was often short term (<12 weeks), with a relative lack of evidence on long-term outcomes (>1 year). Conclusions: This review has highlighted considerable diversity in patient-reported outcome measurements in randomized control trials in the context of adult auditory rehabilitation. In addition, there are gaps in the literature with respect to measurement of other outcome types of potential interest to stakeholders, including policymakers and commissioners. Long-term outcome assessment is rare. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.The Role of Dysfunctional Cognitions in Patients With Chronic Tinnitus.
Conrad, Isabell; Kleinstäuber, Maria; Jasper, Kristine; Hiller, Wolfgang; Andersson, Gerhard; Weise, Cornelia, 2015-06-24 08:00:00 AM
Objectives: The present study investigates the role of dysfunctional cognitions in patients with chronic tinnitus. To explore different dimensions of tinnitus-related thoughts, a 22-item self-report measure, the "Tinnitus Cognitions Scale" (T-Cog), is presented. Furthermore, dysfunctional cognitions are examined as a possible mediator of the relation between tinnitus distress and depression. Design: The present study analyzes the cross-sectional data of 373 patients with chronic tinnitus. Parallel analysis and principal axis factoring are used to identify the factor structure of the T-Cog. Assumed mediating effects are tested using the asymptotic and resampling procedure. Results: Factor analysis reveals two factors interpreted as "tinnitus-related catastrophic thinking" and "tinnitus-related avoidance cognitions." Internal consistency is sufficient with a Cronbach's [alpha] of 0.88 for the total scale and 0.74 and 0.87 for the subscales. The authors find high associations between the T-Cog and other measures of tinnitus distress, depression, anxiety, and tinnitus acceptance, indicating convergent validity. With the exception of neuroticism, low correlations with personality factors are found, indicating discriminant validity. Patients with moderate or severe tinnitus distress report significantly higher scores of dysfunctional cognitions than patients with mild tinnitus distress. Tinnitus-related catastrophic thinking and tinnitus-related avoidance cognitions partially mediate the relation between tinnitus distress and depression. Conclusions: Dysfunctional cognitions can play an important role in the degree of tinnitus distress. Catastrophic and avoidant thoughts contribute to the explanation of depression among tinnitus patients. The T-Cog is a reliable and valid questionnaire for the assessment of different dimensions of cognitions. Its use could provide information for identifying tinnitus patients who are particularly suitable for cognitive-behavioral therapy. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Physical Activity, Tinnitus Severity, and Improved Quality of Life.
Carpenter-Thompson, Jake R.; McAuley, Edward; Husain, Fatima T., 2015-06-24 08:00:00 AM
Objectives: The objective of this study was to examine the effects of tinnitus severity on quality of life (QOL) and the benefits physical activity may have on tinnitus severity and QOL. The authors hypothesized that (1) QOL would be negatively correlated with tinnitus severity, (2) physical activity would be negatively correlated with tinnitus severity, (3) tinnitus severity and physical activity would have significant independent effects on QOL, and (4) physical activity would have significant and independent effects on tinnitus severity. Design: An online survey was used to collect data from adults with tinnitus; 1030 individuals initiated the survey. Approximately 40% of responses were not included in data analysis due to incomplete data. The following measures were included in the survey: the Tinnitus Functional Index, the Godin Leisure-Time Exercise Question, the Medical Outcomes Study 36-item short form (Physical Component Score [PCS]; Mental Component Score [MCS]), and the Satisfaction with Life Scale (SWLS). Descriptive statistics, Pearson correlations, and multiple linear regression analyses were conducted. Results: Higher levels of physical activity were significantly associated with improved health-related and global QOL and lower levels of tinnitus severity. Both tinnitus severity (12.3% SWLS, 3.8% PCS, and 21.2% MCS) and physical activity (1.1% SWLS, 5.8% PCS, and 1.1% MCS) accounted for significant unique variations in the QOL measures. Physical activity accounted (0.8% Tinnitus Functional Index) for significant unique variation in tinnitus severity. Conclusions: Physical activity had a small but statistically significant correlation with QOL and tinnitus distress. Our results suggest that physical activity may be a management strategy for those with tinnitus, but further testing is necessary to assess the relationship between physical activity and tinnitus severity. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Musical Sound Quality in Cochlear Implant Users: A Comparison in Bass Frequency Perception Between Fine Structure Processing and High-Definition Continuous Interleaved Sampling Strategies.
Roy, Alexis T.; Carver, Courtney; Jiradejvong, Patpong; Limb, Charles J., 2015-06-24 08:00:00 AM
Objectives: Med-El cochlear implant (CI) patients are typically programmed with either the fine structure processing (FSP) or high-definition continuous interleaved sampling (HDCIS) strategy. FSP is the newer-generation strategy and aims to provide more direct encoding of fine structure information compared with HDCIS. Since fine structure information is extremely important in music listening, FSP may offer improvements in musical sound quality for CI users. Despite widespread clinical use of both strategies, few studies have assessed the possible benefits in music perception for the FSP strategy. The objective of this study is to measure the differences in musical sound quality discrimination between the FSP and HDCIS strategies. Design: Musical sound quality discrimination was measured using a previously designed evaluation, called Cochlear Implant-MUltiple Stimulus with Hidden Reference and Anchor (CI-MUSHRA). In this evaluation, participants were required to detect sound quality differences between an unaltered real-world musical stimulus and versions of the stimulus in which various amount of bass (low) frequency information was removed via a high-pass filer. Eight CI users, currently using the FSP strategy, were enrolled in this study. In the first session, participants completed the CI-MUSHRA evaluation with their FSP strategy. Patients were then programmed with the clinical-default HDCIS strategy, which they used for 2 months to allow for acclimatization. After acclimatization, each participant returned for the second session, during which they were retested with HDCIS, and then switched back to their original FSP strategy and tested acutely. Sixteen normal-hearing (NH) controls completed a CI-MUSHRA evaluation for comparison, in which NH controls listened to music samples under normal acoustic conditions, without CI stimulation. Results: Sensitivity to high-pass filtering more closely resembled that of NH controls when CI users were programmed with the clinical-default FSP strategy compared with performance when programmed with HDCIS (mixed-design analysis of variance, p < 0.05). Conclusions: The clinical-default FSP strategy offers improvements in musical sound quality discrimination for CI users with respect to bass frequency perception. This improved bass frequency discrimination may in turn support enhanced musical sound quality. This is the first study that has demonstrated objective improvements in musical sound quality discrimination with the newer-generation FSP strategy. These positive results may help guide the selection of processing strategies for Med-El CI patients. In addition, CI-MUSHRA may also provide a novel method for assessing the benefits of newer processing strategies in the future. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.The Relationship Between Insertion Angles, Default Frequency Allocations, and Spiral Ganglion Place Pitch in Cochlear Implants.
Landsberger, David M.; Svrakic, Maja; Roland, J. Thomas Jr; Svirsky, Mario, 2015-06-24 08:00:00 AM
Objectives: Commercially available cochlear implant systems attempt to deliver frequency information going down to a few hundred Hertz, but the electrode arrays are not designed to reach the most apical regions of the cochlea, which correspond to these low frequencies. This may cause a mismatch between the frequencies presented by a cochlear implant electrode array and the frequencies represented at the corresponding location in a normal-hearing cochlea. In the following study, the mismatch between the frequency presented at a given cochlear angle and the frequency expected by an acoustic hearing ear at the corresponding angle is examined for the cochlear implant systems that are most commonly used in the United States. Design: The angular insertion of each of the electrodes on four different electrode arrays (MED-EL Standard, MED-EL Flex28, Advanced Bionics HiFocus 1J, and Cochlear Contour Advance) was estimated from X-ray. For the angular location of each electrode on each electrode array, the predicted spiral ganglion frequency was estimated. The predicted spiral ganglion frequency was compared with the center frequency provided by the corresponding electrode using the manufacturer's default frequency-to-electrode allocation. Results: Differences across devices were observed for the place of stimulation for frequencies below 650 Hz. Longer electrode arrays (i.e., the MED-EL Standard and Flex28) demonstrated smaller deviations from the spiral ganglion map than the other electrode arrays. For insertion angles up to approximately 270[degrees], the frequencies presented at a given location were typically approximately an octave below what would be expected by a spiral ganglion frequency map, while the deviations were larger for angles deeper than 270[degrees]. For frequencies above 650 Hz, the frequency to angle relationship was consistent across all four electrode models. Conclusions: A mismatch was observed between the predicted frequency and the default frequency provided by every electrode on all electrode arrays. The mismatch can be reduced by changing the default frequency allocations, inserting electrodes deeper into the cochlea, or allowing cochlear implant users to adapt to the mismatch. Further studies are required to fully assess the clinical significance of the frequency mismatch. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Extended High-Frequency Bandwidth Improves Speech Reception in the Presence of Spatially Separated Masking Speech.
Levy, Suzanne Carr; Freed, Daniel J.; Nilsson, Michael; Moore, Brian C. J.; Puria, Sunil, 2015-06-24 08:00:00 AM
Objectives: The hypothesis that extending the audible frequency bandwidth beyond the range currently implemented in most hearing aids can improve speech understanding was tested for normal-hearing and hearing-impaired participants using target sentences and spatially separated masking speech. Design: The Hearing In Speech Test (HIST) speech corpus was re-recorded, and four masking talkers were recorded at a sample rate of 44.1 kHz. All talkers were male native speakers of American English. For each subject, the reception threshold for sentences (RTS) was measured in two spatial configurations. In the asymmetric configuration, the target was presented from -45[degrees] azimuth and two colocated masking talkers were presented from +45[degrees] azimuth. In the diffuse configuration, the target was presented from 0[degrees] azimuth and four masking talkers were each presented from a different azimuth: +45[degrees], +135[degrees], -135[degrees], and -45[degrees]. The new speech sentences, masking materials, and configurations were presented using low-pass filter cutoff frequencies of 4, 6, 8, and 10 kHz. For the normal-hearing participants, stimuli were presented in the sound field using loudspeakers. For the hearing-impaired participants, the spatial configurations were simulated using earphones, and a multiband wide-dynamic-range compressor with a modified CAM2 fitting algorithm was used to compensate for each participant's hearing loss. Results: For the normal-hearing participants (N = 24, mean age 40 years), the RTS improved significantly by 3.0 dB when the bandwidth was increased from 4 to 10 kHz, and a significant improvement of 1.3 dB was obtained from extending the bandwidth from 6 to 10 kHz, in both spatial configurations. Hearing-impaired participants (N = 25, mean age 71 years) also showed a significant improvement in RTS with extended bandwidth, but the effect was smaller than for the normal-hearing participants. The mean decrease in RTS when the bandwidth was increased from 4 to 10 kHz was 1.3 dB for the asymmetric condition and 0.5 dB for the diffuse condition. Conclusions: Extending bandwidth from 4 to 10 kHz can improve the ability of normal-hearing and hearing-impaired participants to understand target speech in the presence of spatially separated masking speech. Future studies of the benefits of extended high-frequency amplification should investigate other realistic listening situations, masker types, spatial configurations, and room reverberation conditions, to determine added value in overcoming the technical challenges associated with implementing a device capable of providing extended high-frequency amplification. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Amplitude Modulation Detection and Speech Recognition in Late-Implanted Prelingually and Postlingually Deafened Cochlear Implant Users.
De Ruiter, Anke M.; Debruyne, Joke A.; Chenault, Michelene N.; Francart, Tom; Brokx, Jan P. L., 2015-06-24 08:00:00 AM
Objectives: Many late-implanted prelingually deafened cochlear implant (CI) patients struggle to obtain open-set speech understanding. Because it is known that low-frequency temporal-envelope information contains important cues for speech understanding, the goal of this study was to compare the temporal-envelope processing abilities of late-implanted prelingually and postlingually deafened CI users. Furthermore, the possible relation between temporal processing abilities and speech recognition performances was investigated. Design: Amplitude modulation detection thresholds were obtained in eight prelingually and 18 postlingually deafened CI users, by means of a sinusoidally modulated broadband noise carrier, presented through a loudspeaker to the CI user's clinical device. Thresholds were determined with a two-down-one-up three-interval oddity adaptive procedure, at seven modulation frequencies. Phoneme recognition (consonant-nucleus-consonant [CNC]) scores (percentage correct at 65 dB SPL) were gathered for all CI users. For the prelingually deafened group, scores on two additional speech tests were obtained: (1) a closed-set monosyllable-trochee-spondee test (percentage correct scores at 65 dB SPL on word recognition and categorization of the suprasegmental word patterns), and (2) a speech tracking test (number of correctly repeated words per minute) with texts specifically designed for this population. Results: The prelingually deafened CI users had a significantly lower sensitivity to amplitude modulations than the postlingually deafened CI users, and the attenuation rate of their temporal modulation transfer function (TMTF) was greater. None of the prelingually deafened CI users were able to detect modulations at 150 and 200 Hz. High and significant correlations were found between the results on the amplitude modulation detection test and CNC phoneme scores, for the entire group of CI users. In the prelingually deafened group, CNC phoneme scores, word scores on the monosyllable-trochee-spondee test, and speech tracking scores correlated significantly with the mean amplitude modulation detection threshold of the modulation frequencies between 5 and 100 Hz and with almost all separate amplitude modulation thresholds. High correlations with these speech measures were also found for the attenuation rate of and the surface area below the TMTF. In postlingually deafened CI users, CNC phoneme scores only correlated significantly with the 100-Hz and 150-Hz amplitude modulation thresholds, as well as with the attenuation rate of and surface area below the TMTF. Conclusions: Prelingually deafened CI users were less sensitive to temporal modulations than postlingually deafened CI users, and the attenuation rate of their TMTF was steeper. For all CI users, subjects with better amplitude modulation detection skills tended to score better on measures of speech understanding. Significant correlations with low modulation frequencies were found only for the prelingually deafened CI users and not for the postlingually deafened CI users. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Comparison of Psychophysical and Physical Measurements of Real Ear to Coupler Differences.
Koning, Raphael; Wouters, Jan; Francart, Tom, 2015-06-24 08:00:00 AM
Objectives: The purpose of the study is to compare real ear to coupler difference (RECD) curves based on physical and psychophysical measures. For the physically measured RECD, the RECD was measured with real ear and coupler measurements for the ear simulator and HA1- and HA2 2-cc couplers. The psychophysically measured RECDs were derived from audiogram measures. Design: RECDs were measured in 19 normally hearing subjects. The coupler measurement was done with the probe microphone and the coupler microphone itself. Psychophysically measured RECDs were derived for all subjects by measuring the audiogram in sound field and with an ER-3A insert phone. Results: Reference data were obtained for the three coupler types. It was possible to derive the RECD curve with psychophysical methods. There was no overall statistical difference between the physically and psychophysically measured RECD curves for the HA2 2-cc coupler and the ear simulator. The standard deviation was, however, much higher for the psychophysically derived RECD, indicating that physically measured RECDs are more precise than psychophysically derived RECDs. Conclusions: For the physical RECD measurements, the coupler microphone should be used for the coupler measurement. Physically measured RECDs were validated on group level by the reliable derivation of the RECD curve from audiogram measures. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Processing of Horizontal Sound Localization Cues in Newborn Infants.
Németh, Renáta; Háden, Gábor P.; Török, Miklós; Winkler, István, 2015-06-24 08:00:00 AM
Objectives: By measuring event-related brain potentials (ERPs), the authors tested the sensitivity of the newborn auditory cortex to sound lateralization and to the most common cues of horizontal sound localization. Design: Sixty-eight healthy full-term newborn infants were presented with auditory oddball sequences composed of frequent and rare noise segments in four experimental conditions. The authors tested in them the detection of deviations in the primary cues of sound lateralization (interaural time and level difference) and in actual sound source location (free-field and monaural sound presentation). ERP correlates of deviance detection were measured in two time windows. Results: Deviations in both primary sound localization cues and the ear of stimulation elicited a significant ERP difference in the early (90 to 140 msec) time window. Deviance in actual sound source location (the free-field condition) elicited a significant response in the late (290 to 340 msec) time window. Conclusions: The early differential response may indicate the detection of a change in the respective auditory features. The authors suggest that the late differential response, which was only elicited by actual sound source location deviation, reflects the detection of location deviance integrating the various cues of sound source location. Although the results suggest that all of the tested binaural cues are processed by the neonatal auditory cortex, utilizing the cues for locating sound sources of these cues may require maturation and learning. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Evaluating Inhibition of Motoneuron Firing From Electromyogram Data to Assess Vestibular Output Using Vestibular Evoked Myogenic Potentials.
Prakash, S. R.; Herrmann, Barbara S.; Milojcic, Rupprecht; Rauch, Steven D.; Guinan, John J. Jr, 2015-06-24 08:00:00 AM
Objectives: Vestibular evoked myogenic potentials (VEMPs) are due to vestibular responses producing brief inhibitions of muscle contractions that are detectable in electromyographic (EMG) responses. VEMP amplitudes are traditionally measured by the peak to peak amplitude of the averaged EMG response (VEMPpp) or by a normalized VEMPpp (nVEMPpp). However, a brief EMG inhibition does not satisfy the statistical assumptions for the average to be the optimal processing strategy. Here, it is postulated that the inhibition depth of motoneuron firing is the desired metric for showing the influence of the vestibular system on the muscle system. The authors present a metric called "VEMPid" that estimates this inhibition depth from the EMG data obtained in a usual VEMP data acquisition. The goal of this article was to compare how well VEMPid, VEMPpp, and nVEMPpp track inhibition depth. Design: To find a robust method to compare VEMPid, VEMPpp, and nVEMPpp, realistic physiological models for the inhibition of VEMP EMG signals were made using VEMP data from four measurement sessions on each of the five normal subjects. Each of the resulting 20 EMG-production models was adjusted to match the EMG autocorrelation of an individual subject and session. Simulated VEMP traces produced by these models were used to compare how well VEMPid, VEMPpp, and nVEMPpp tracked model inhibition depth. Results: Applied to simulated and real VEMP data, VEMPid showed good test-retest consistency and greater sensitivity at low stimulus levels than VEMPpp or nVEMPpp. For large-amplitude responses, nVEMPpp and VEMPid were equivalent in their consistency across subjects and sessions, but for low-amplitude responses, VEMPid was superior. Unnormalized VEMPpp was always worse than nVEMPpp or VEMPid. Conclusions: VEMPid provides a more reliable measurement of vestibular function at low sound levels than the traditional nVEMPpp, without requiring a change in how VEMP tests are performed. The calculation method for VEMPid should be applicable whenever an ongoing muscle contraction is briefly inhibited by an external stimulus. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Exploring the Effects of the Narrative Embodied in the Hearing Aid Fitting Process on Treatment Outcomes.
Naylor, Graham; Öberg, Marie; Wänström, Gunilla; Lunner, Thomas, 2015-06-24 08:00:00 AM
Objectives: There is strong evidence from other fields of health, and growing evidence in audiology, that characteristics of the process of intervention as perceived by the client (embodied narratives) can have significant effects on treatment outcomes, independent of the technical properties of the intervention itself. This phenomenon deserves examination because studies of technical interventions that fail to take account of it may reach erroneous conclusions and because clinical practice can put such effects to therapeutic use. The aim of this study was to test the idea that embodied narratives might affect outcomes in hearing aid fitting. This was achieved by carrying out experiments in which technical (acoustic) differences between alternative hearing aid fittings were absent, while providing test subjects with a strong contrast between the processes apparently applied to derive the fittings being compared. Thus, any effects of contrasting narratives could be observed, free of acoustical confounds. The hypothesis was that narrative effects would be observed. Design: A balanced crossover design was used, in which subjects received and evaluated two bilateral hearing aid fittings in succession. Subjects were deceived as to the true identical content of the hearing aid fittings being compared, but encouraged to believe that one fitting process was "interactive" and the other was "diagnostic" in character. Two almost identical experiments were undertaken: one with 24 experienced adult hearing aid users and another with 16 adult first-time users. Each hearing aid fitting was worn at home for 2 weeks, after which self-report outcome measures (Hearing Aid Performance Questionnaire, Hearing Handicap Inventory for the Elderly, and International Outcome Inventory for Hearing Aids) were administered. After the second test period, a short preference questionnaire was also completed. Results: Twenty of the 24 experienced users showed a clear preference for one or the other fitting, and their self-report scores reflected these preferences. Effect sizes were comparable with those typically observed for true acoustical contrasts. No order effect was seen in this group. In contrast, 13 of the 16 first-time users preferred the second fitting. Trends in the self-report measures were similar for this group but weaker than for the experienced users. In both groups, the reasons given for subjects' preference were predominantly related to sound, despite there being no acoustical differences. Conclusions: This study suggests that the narrative embodied in a given fitting process can have a substantial effect on the perceived benefit of the treatment, independent of any acoustical differences, at least for experienced users. For first-time users, acclimatization seems to overshadow the purely narrative effect of any fitting process. In the future, research study designs should include steps to avoid narrative effects when technical parameters of hearing aids are the intended object of study. In clinical practice, the narrative is part of the therapeutic context, and one may design it for maximum beneficial effect. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Psychophysical Map Stability in Bilateral Sequential Cochlear Implantation: Comparing Current Audiology Methods to a New Statistical Definition.
Domville-Lewis, Chloe; Santa Maria, Peter L.; Upson, Gemma; Chester-Browne, Ronel; Atlas, Marcus D., 2015-06-24 08:00:00 AM
Objectives: The purpose of this study was to establish a statistical definition for stability in cochlear implant maps. Once defined, this study aimed to compare the duration taken to achieve a stable map in first and second implants in patients who underwent sequential bilateral cochlear implantation. This article also sought to evaluate a number of factors that potentially affect map stability. Design: A retrospective cohort study of 33 patients with sensorineural hearing loss who received sequential bilateral cochlear implantation (Cochlear, Sydney, Australia), performed by the senior author. Psychophysical parameters of hearing threshold scores, comfort scores, and the dynamic range were measured for the apical, medial, and basal portions of the cochlear implant electrode at a range of intervals postimplantation. Stability was defined statistically as a less than 10% difference in threshold, comfort, and dynamic range scores over three consecutive mapping sessions. A senior cochlear implant audiologist, blinded to implant order and the statistical results, separately analyzed these psychophysical map parameters using current assessment methods. First and second implants were compared for duration to achieve stability, age, gender, the duration of deafness, etiology of deafness, time between the insertion of the first and second implant, and the presence or absence of preoperative hearing aids were evaluated and its relationship to stability. Statistical analysis included performing a two-tailed Student's t tests and least squares regression analysis, with a statistical significance set at p <= 0.05. Results: There was a significant positive correlation between the devised statistical definition and the current audiology methods for assessing stability, with a Pearson correlation coefficient r = 0.36 and a least squares regression slope (b) of 0.41, df(58), 95% confidence interval 0.07 to 0.55 (p = 0.004). The average duration from device switch on to stability in the first implant was 87 days using current audiology methods and 81 days using the statistical definition, with no statistically significant difference between assessment methods (p = 0.2). The duration to achieve stability in the second implant was 51 days using current audiology methods and 60 days using the statistical method, and again no difference between the two assessment methods (p = 0.13). There was a significant reduction in the time to achieve stability in second implants for both audiology and statistical methods (p < 0.001 and p = 0.02, respectively). There was a difference in duration to achieve stability based on electrode array region, with basal portions taking longer to stabilize than apical in the first implant (p = 0.02) and both apical and medial segments in second implants (p = 0.004 and p = 0.01, respectively). No factors that were evaluated in this study, including gender, age, etiology of deafness, duration of deafness, time between implant insertion, and the preoperative hearing aid status, were correlated with stability duration in either stability assessment method. Conclusions: Our statistical definition can accurately predict cochlear implant map stability when compared with current audiology practices. Cochlear implants that are implanted second tend to stabilize sooner than the first, which has a significant impact on counseling before a second implant. No factors evaluated affected the duration required to achieve stability in this study. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.Validity of Automated Threshold Audiometry: A Systematic Review and Meta-Analysis.
Mahomed, Faheema; Swanepoel, De Wet; Eikelboom, Robert H.; Soer, Maggi, 2015-06-24 08:00:00 AM
Objectives: A systematic literature review and meta-analysis on the validity (test-retest reliability and accuracy) of automated threshold audiometry compared with the gold standard of manual threshold audiometry was conducted. Design: A systematic literature review was completed in peer-reviewed databases on automated compared with manual threshold audiometry. Subsequently a meta-analysis was conducted on the validity of automated audiometry. A multifaceted approach, covering several databases and using different search strategies was used to ensure comprehensive coverage and to cross-check search findings. Databases included: MEDLINE, SCOPUS, and PubMed with a secondary search strategy reviewing references from identified reports. Reports including within-subject comparisons of manual and automated threshold audiometry were selected according to inclusion/exclusion criteria before data were extracted. For the meta-analysis weighted mean differences (and standard deviations) on test-retest reliability for automated compared with manual audiometry were determined to assess the validity of automated threshold audiometry. Results: In total, 29 reports on automated audiometry (method of limits and the method of adjustment techniques) met the inclusion criteria and were included in this review. Most reports included data on adult populations using air conduction testing with limited data on children, bone conduction testing, and the effects of hearing status on automated audiometry. Meta-analysis test-retest reliability for automated audiometry was within typical test-retest variability for manual audiometry. Accuracy results on the meta-analysis indicated overall average differences between manual and automated air conduction audiometry (0.4 dB; 6.1 SD) to be comparable with test-retest differences for manual (1.3 dB; 6.1 SD) and automated (0.3 dB; 6.9 SD) audiometry. Nosignificant differences (p > 0.01; summarized data analysis of variance) were seen in any of the comparisons between test-retest reliability of manual and automated audiometry compared with differences between manual and automated audiometry. Conclusions: Automated audiometry provides an accurate measure of hearing threshold, but validation data are still limited for (a) automated bone conduction audiometry; (b) automated audiometry in children and difficult-to-test populations; and (c) different types and degrees of hearing loss. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.
Παρασκευή 14 Αυγούστου 2015
Ear and Hearing - Published Ahead-of-Print
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