Hearing aid noise reduction algorithms and the acquisition of novel speech contrasts by young children

A previous study by the authors concluded that digital noise reduction (DNR) does not have an influence on the acquisition of a second language in adults. On the basis of results from adult subjects, it was inferred that DNR is not likely to influence language acquisition in pre-verbal infants. The present study serves as an update to determine whether the tasks being modeled could be conducted with younger participants of 4-and 5-years of age, and whether similar results would be found. Two groups of normal-hearing, monolingual English-speaking children were presented with noise-embedded Hindi speech contrasts that were difficult to discriminate. One group listened to both speech items and noise processed with DNR while the other group listened to unprocessed speech in noise. To ensure task appropriateness, these results were also compared to measures from a third group composed of Hindi-speaking children of the same age. Results indicated that Hindi-speaking children performed better than English-speaking children, confirming age-appropriateness of the cross-language task, but that DNR did not enhance nor impair the acquisition of novel speech contrasts by young listeners.

from the Canadian Journal of Speech-Language Pathology and Audiology</p

Hearing aids: A contemporary review

contemporary review of hearing aids is provided with a focus on current styles of amplification devices, the goals of a hearing aid fitting and the signal processing schemes that allow the clinician to meet these goals, and the need to couple outside devices to hearing aids. A variety of new features available on hearing aids that improve the listener’s experience with amplification are described. Some future challenges in hearing aid design and hearing evaluation are presented.

from The Laryngoscope

Directional Effects on Infants and Young Children in Real Life: Implications for Amplification

Method: Twenty-seven children (11 with normal hearing, 16 with impaired hearing) between 11 and 78 months of age were video recorded in naturalistic settings for analyses of head orientation. Reports on daily activities were obtained from caregivers. The effect of directionality in different environments was quantified by measuring the Speech Transmission Index (STI; H. J. M. Steeneken & T. Houtgast, 1980).

Results: Averaged across 4 scenarios, children looked in the direction of a talker for 40% of the time when speech was present. Head orientation was not affected by age or hearing status. The STI measurements revealed a directional advantage of 3 dB when a child looked at a talker but a deficit of 2.8 dB when the talker was sideways or behind the child. The overall directional effect in real life was between –0.4 and 0.2 dB.

Conclusions: The findings suggest that directional microphones in personal hearing devices for young children are not detrimental and have much potential for benefits in real life. The benefits may be enhanced by fitting directionality early and by counseling caregivers on ways to maximize benefits in everyday situations.

from the Journal of Speech, Language, and Hearing Research

Directional effects on infants and young children in real life: Implications for amplification

Results: Averaged across 4 scenarios, children looked in the direction of a talker for 40% of the time when speech was present. Head orientation was not affected by age or hearing status. The STI measurements revealed a directional advantage of 3 dB when a child looked at a talker, but a deficit of 2.8 dB when the talker was sideways or behind the child. The overall directional effect in real life was between –0.4 and 0.2 dB.

Conclusions: The findings suggest that directional microphones in personal hearing devices for young children are not detrimental, and have much potential for benefits in real life. The benefits may be enhanced by fitting directionality early and by counselling caregivers on ways to maximize benefits in everyday situations.

from the Journal of Speech, Language, and Hearing Research

Development of Mandarin monosyllabic speech test materials in China

In this study, monosyllabic Mandarin speech test materials (MSTMs) were developed for use in word recognition tests for speech audiometry in Chinese audiology clinics. Mandarin monosyllabic materials with high familiarity were designed with regard to phonological balance and recorded digitally with a male voice. Inter-list equivalence of difficulty was evaluated for a group of 60 subjects (aged 18-25 years) with normal hearing. Seven lists with 50 words each were found to be equivalent. These seven equivalent lists were used to measure performance-intensity (PI) functions for a group of 32 subjects with normal hearing and a group of 40 subjects with mild to moderate sensorineural hearing loss. The mean slope of PI function was found to be 4.1%/dB and 2.7%/dB, respectively. The seven lists of Mandarin monosyllabic materials were found to have sufficient reliability and validity to be used in clinical situations.

from the International Journal of Audiology

A systematic review to determine the effectiveness of using amplification in conjunction with cochlear implantation

Method: RESEARCH DESIGN: A systematic review of the evidence that met the search criteria related to the use of amplification in adult implant users. All types of experiments were included with the exception of expert opinion. This systematic review ranked the levels of evidence related to these studies and distinguished the levels of evidence from judgments about the grade and strength of recommendations for the stated clinical question. STUDY SAMPLE: Fifty-two articles were initially reviewed with a final 11 articles meeting the search criteria and identified for in-depth analysis. DATA COLLECTION AND ANALYSIS: Several electronic databases and textbooks were searched to locate the evidence related to bimodal stimulation. Each article was reviewed using a check sheet and assigned a ranking for level of evidence (Levels 1-6) based on the type of research design that was used and a grade of evidence (A-D) based on the quality, relevance, and extensiveness of the study. Finally the level and grade were collapsed into only three categories to indicating the strength of the recommendations coming from each study and were classified as either strong (I), moderate (II), or weak (III).

Results: Several trends about bimodal stimulation were observed, which include (1) significantly better speech understanding in the bimodal condition for many participants; (2) in noise, the largest bimodal benefits in speech recognition; (3) variable findings on localization tasks; and (4) overall significant improvement in functional ability based on self-assessments. The preponderance of evidence received grades of B or C.

from

Development of Mandarin monosyllabic speech test materials in China

In this study, monosyllabic Mandarin speech test materials (MSTMs) were developed for use in word recognition tests for speech audiometry in Chinese audiology clinics. Mandarin monosyllabic materials with high familiarity were designed with regard to phonological balance and recorded digitally with a male voice. Inter-list equivalence of difficulty was evaluated for a group of 60 subjects (aged 18-25 years) with normal hearing. Seven lists with 50 words each were found to be equivalent. These seven equivalent lists were used to measure performance-intensity (PI) functions for a group of 32 subjects with normal hearing and a group of 40 subjects with mild to moderate sensorineural hearing loss. The mean slope of PI function was found to be 4.1%/dB and 2.7%/dB, respectively. The seven lists of Mandarin monosyllabic materials were found to have sufficient reliability and validity to be used in clinical situations.

from the International Journal of Audiology

Frequency-Lowering Devices for Managing High-Frequency Hearing Loss: A Review

Frequency-lowering technology has been around for decades. The primary aim—namely, that of providing high-frequency information to those with severe high-frequency hearing loss—addresses a clinical need most conventional hearing devices are still unable to provide. Early studies with frequency-lowering technology reported mostly unfavorable results, and the devices never gained clinical popularity. However, as hearing aid (HA) technology becomes ever more sophisticated, it is appropriate to reconsider whether frequency-lowering HAs should be an amplification choice in those with high-frequency hearing loss. Recent research is yielding promise with people who wear frequency-lowering devices showing improved speech perception. Questions remain regarding patient candidacy and whether auditory training may result in better outcomes. The author also discusses future clinical directions and research needs for frequency lowering.

from Trends in Amplification

An evaluation of frequency transposition for hearing-impaired school-age children

A key objective when fitting hearing aids to children is to maximize the audibility of high frequency speech cues which are critical in the understanding of spoken English. Recent advances in digital signal processing have enabled the development of hearing aids which offer linear frequency transposition as a new way of accessing these important speech sounds. This study examined the changes in aided performance observed in children with hearing impairment who trialed the alternative hearing aid technology. The rationale behind the research was to evaluate the benefits of this new technology, as applied in the commercially available Widex Inteo hearing aid, for a group of children with sloping high frequency sensori-neural hearing loss (n = 6). The participants were aged between 9 and 14 years and all attended mainstream schools. Outcome measures were comprised of tests of speech perception and speech production and questionnaires. Speech perception abilities were measured using CNC word and phoneme tests, with and without frequency transposition in both the audiovisual and visual alone modalities at 6 weekly intervals for 24 weeks. The Goldman-Fristoe 2 Test of Articulation was the chosen measure of speech production and was administered prior to the new aid fitting and after 24 weeks of frequency transposition use. Results showed statistically significant improvements for the group as a whole on both these measures. These results were supported by positive reporting on the questionnaires completed by key stakeholders. Copyright © 2009 John Wiley & Sons, Ltd.

from Deafness and Education International

Studies of Hearing-Aid Outcome Measures in Older Adults: A Comparison of Technologies and an Examination of Individual Differences

ABSTRACT
This article first compares differences in hearing-aid outcome for groups of older adults fitted with different hearing-aid technologies, ranging from one-channel linear aids with output-limiting compression to four-channel wide-dynamic-range-compression devices with directional microphones. A total of four technologies were examined with 52 to 55 older adults fitted with each technology and assessed with multiple outcome measures. The only significant difference in performance across technologies was superior aided speech recognition in babble for the directional hearing aids when assessed in the sound booth with speech delivered at 0 degrees azimuth and competing babble delivered from 180 degrees azimuth. Importantly, however, all four groups, each with a different technology, demonstrated significant improvements in speech recognition in babble and indicated that they were satisfied with their hearing aids, found them to be beneficial, and used them ~7 to 8 hours per day, on average. Given the lack of differences in technology, the data were then pooled across groups to form one large data set of outcome measures from 333 older adults. From these data, guidelines were developed for the interpretation of individual scores from patients in other clinics with similar demographics as being “below average,” “average,” or “above average.”

from Seminars in Hearing

An approach to bilateral bone-anchored hearing aid surgery in children: contralateral placement of sleeper fixture

Conclusions: In children with bilateral conductive hearing loss, in whom a bilateral bone-anchored hearing aid is being considered and the second side is to be operated upon at a later date, we recommend placing the sleeper fixture on the contralateral side at the time of primary first-side surgery. Our technique provides a sleeper fixture located in an optimal position, where it also offers the option of use for a second-side bone-anchored hearing aid and reduces the number of procedures needed.

from the Journal of Laryngology and Otology

human evoked cortical activity to signal-to-noise ratio and absolute signal level

Abstract
The purpose of this study was to determine the effect of signal level and signal-to-noise ratio (SNR) on the latency and amplitude of evoked cortical activity to further our understanding of how the human central auditory system encodes signals in noise. Cortical auditory evoked potentials (CAEPs) were recorded from 15 young normal-hearing adults in response to a 1000 Hz tone presented at two tone levels in quiet and while continuous background noise levels were varied in five equivalent SNR steps. These 12 conditions were used to determine the effects of signal level and SNR level on CAEP components P1, N1, P2, and N2. Based on prior signal-in-noise experiments conducted in animals, we hypothesized that SNR, would be a key contributor to human CAEP characteristics. As hypothesized, amplitude increased and latency decreased with increasing SNR; in addition, there was no main effect of tone level across the two signal levels tested (60 and 75 dB SPL). Morphology of the P1-N1-P2 complex was driven primarily by SNR, highlighting the importance of noise when recording CAEPs. Results are discussed in terms of the current interest in recording CAEPs in hearing aid users.

from Hearing Research

Speech perception with hearing aids: Effects of noise reduction and directional microphone systems on amplified signals

Our objective was to measure the variations of speech reception threshold (SRT) in noise induced by hearing aids with or without noise reduction (NR) and directional microphone systems (DM). Data were collected from 10 normal hearing volunteers wearing bilateral hearing aids and tested in a sound field of speech and noise. SRT was measured in function of: 1) speech source azimuth (0°,90°,180°); 2) background noise (monophonic vs. quadraphonic); 3) amplification (unaided vs. linearly aided); 4) amplification mode (linear, NR, DM, NR+DM). Compared using a hearing aid linear setting, NR does not improve the SRT in monophonic noise, while it improves the SRT by 2-3dB in quadraphonic noise with frontal and lateral speech. DM in monophonic noise improves frontal SRT (1dB) and worsens lateral and posterior SRT, while in quadraphonic noise frontal SRT is further advantaged and the DM negative effect disappears. With both devices activated a stronger positive effect is evident for frontal SRT in both noise fields (2-4dB) and for lateral SRT in quadraphonic noise. These results confirm that NR and DM can facilitate SRT in adverse noise conditions for normal hearing persons, and the results are useful as a reference for hearing impaired persons.

from Audiological Medicine

Economic viability of stapes surgery in Germany

Conclusion: Stapes surgery is economically beneficial for the individual patient as well as for the general patient cohort, irrespective of age. The stapedotomy procedure also prevents the known disadvantages of conventional hearing aids, thus improving the patient’s quality of life.

from the Journal of Laryngology and Otology

Pediatric cochlear implantation: How much hearing is too much?

Audiologic candidacy criteria for determining cochlear implantation candidacy in children are evolving. The objective of the study was to examine clinical practice related to the cochlear implantation of children who typically do not meet audiologic criteria for this technology. Practitioners’ perspectives on the process and the factors influencing candidacy decisions were explored through focus group interviews with hospital and school-based practitioners. The interviews were analysed using qualitative techniques to identify key issues. The findings from the interviews informed a questionnaire which was sent to all cochlear implant centers in Canada to further examine clinician views and experiences with this special population. Responses were collected from 11 of the 12 centers and indicated that children with hearing outside typical criteria were receiving implants. The definition of ‘borderline’ varied across the programs from approximately 70 dB HL to less than 90 dB HL. All centers emphasized the importance of considering factors beyond the child’s audiometric thresholds in candidacy decision-making.

from the International Journal of Audiology