Σάββατο 13 Φεβρουαρίου 2016

Response of the human tympanic membrane to transient acoustic and mechanical stimuli

Publication date: Available online 12 February 2016
Source:Hearing Research
Author(s): Payam Razavi, Michael E. Ravicz, Ivo Dobrev, Jeffrey Tao Cheng, Cosme Furlong, John J. Rosowski
The response of the tympanic membrane (TM) to transient environmental sounds and the contributions of different parts of the TM to middle-ear sound transmission were investigated by measuring the TM response to global transients (acoustic clicks) and to local transients (mechanical impulses) applied to the umbo and various locations on the TM. A lightly-fixed human temporal bone was prepared by removing the ear canal, inner ear, and stapes, leaving the incus, malleus, and TM intact. Motion of nearly the entire TM was measured by a digital holography system with a high speed camera at a rate of 42 000 frames per second, giving a temporal resolution of <24 μs for the duration of the TM response. The entire TM responded nearly instantaneously to acoustic transient stimuli, though the peak displacement and decay time constant varied with location. With local mechanical transients, the TM responded first locally at the site of stimulation, and the response spread approximately symmetrically and circumferentially around the umbo and manubrium. Acoustic and mechanical transients provide distinct and complementary stimuli for the study of TM response. Spatial variations in decay and rate of spread of response imply local variations in TM stiffness, mass, and damping.

Graphical abstract

image


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Response of the human tympanic membrane to transient acoustic and mechanical stimuli

Publication date: Available online 12 February 2016
Source:Hearing Research
Author(s): Payam Razavi, Michael E. Ravicz, Ivo Dobrev, Jeffrey Tao Cheng, Cosme Furlong, John J. Rosowski
The response of the tympanic membrane (TM) to transient environmental sounds and the contributions of different parts of the TM to middle-ear sound transmission were investigated by measuring the TM response to global transients (acoustic clicks) and to local transients (mechanical impulses) applied to the umbo and various locations on the TM. A lightly-fixed human temporal bone was prepared by removing the ear canal, inner ear, and stapes, leaving the incus, malleus, and TM intact. Motion of nearly the entire TM was measured by a digital holography system with a high speed camera at a rate of 42 000 frames per second, giving a temporal resolution of <24 μs for the duration of the TM response. The entire TM responded nearly instantaneously to acoustic transient stimuli, though the peak displacement and decay time constant varied with location. With local mechanical transients, the TM responded first locally at the site of stimulation, and the response spread approximately symmetrically and circumferentially around the umbo and manubrium. Acoustic and mechanical transients provide distinct and complementary stimuli for the study of TM response. Spatial variations in decay and rate of spread of response imply local variations in TM stiffness, mass, and damping.

Graphical abstract

image


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Effects of Removing Low-Frequency Electric Information on Speech Perception With Bimodal Hearing

Purpose
The objective was to determine whether speech perception could be improved for bimodal listeners (those using a cochlear implant [CI] in one ear and hearing aid in the contralateral ear) by removing low-frequency information provided by the CI, thereby reducing acoustic–electric overlap.
Method
Subjects were adult CI subjects with at least 1 year of CI experience. Nine subjects were evaluated in the CI-only condition (control condition), and 26 subjects were evaluated in the bimodal condition. CIs were programmed with 4 experimental programs in which the low cutoff frequency (LCF) was progressively raised. Speech perception was evaluated using Consonant-Nucleus-Consonant words in quiet, AzBio sentences in background babble, and spondee words in background babble.
Results
The CI-only group showed decreased speech perception in both quiet and noise as the LCF was raised. Bimodal subjects with better hearing in the hearing aid ear ( 60 dB HL at 250 and 500 Hz) performed similarly to the CI-only group.
Conclusions
These findings suggest that reducing low-frequency overlap of the CI and contralateral hearing aid may improve performance in quiet for some bimodal listeners with better hearing.

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Masking Release in Children and Adults With Hearing Loss When Using Amplification

Purpose
This study compared masking release for adults and children with normal hearing and hearing loss. For the participants with hearing loss, masking release using simulated hearing aid amplification with 2 different compression speeds (slow, fast) was compared.
Method
Sentence recognition in unmodulated noise was compared with recognition in modulated noise (masking release). Recognition was measured for participants with hearing loss using individualized amplification via the hearing-aid simulator.
Results
Adults with hearing loss showed greater masking release than the children with hearing loss. Average masking release was small (1 dB) and did not depend on hearing status. Masking release was comparable for slow and fast compression.
Conclusions
The use of amplification in this study contrasts with previous studies that did not use amplification. The results suggest that when differences in audibility are reduced, participants with hearing loss may be able to take advantage of dips in the noise levels, similar to participants with normal hearing. Although children required a more favorable signal-to-noise ratio than adults for both unmodulated and modulated noise, masking release was not statistically different. However, the ability to detect a difference may have been limited by the small amount of masking release observed.

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Effects of Removing Low-Frequency Electric Information on Speech Perception With Bimodal Hearing

Purpose
The objective was to determine whether speech perception could be improved for bimodal listeners (those using a cochlear implant [CI] in one ear and hearing aid in the contralateral ear) by removing low-frequency information provided by the CI, thereby reducing acoustic–electric overlap.
Method
Subjects were adult CI subjects with at least 1 year of CI experience. Nine subjects were evaluated in the CI-only condition (control condition), and 26 subjects were evaluated in the bimodal condition. CIs were programmed with 4 experimental programs in which the low cutoff frequency (LCF) was progressively raised. Speech perception was evaluated using Consonant-Nucleus-Consonant words in quiet, AzBio sentences in background babble, and spondee words in background babble.
Results
The CI-only group showed decreased speech perception in both quiet and noise as the LCF was raised. Bimodal subjects with better hearing in the hearing aid ear ( 60 dB HL at 250 and 500 Hz) performed similarly to the CI-only group.
Conclusions
These findings suggest that reducing low-frequency overlap of the CI and contralateral hearing aid may improve performance in quiet for some bimodal listeners with better hearing.

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Masking Release in Children and Adults With Hearing Loss When Using Amplification

Purpose
This study compared masking release for adults and children with normal hearing and hearing loss. For the participants with hearing loss, masking release using simulated hearing aid amplification with 2 different compression speeds (slow, fast) was compared.
Method
Sentence recognition in unmodulated noise was compared with recognition in modulated noise (masking release). Recognition was measured for participants with hearing loss using individualized amplification via the hearing-aid simulator.
Results
Adults with hearing loss showed greater masking release than the children with hearing loss. Average masking release was small (1 dB) and did not depend on hearing status. Masking release was comparable for slow and fast compression.
Conclusions
The use of amplification in this study contrasts with previous studies that did not use amplification. The results suggest that when differences in audibility are reduced, participants with hearing loss may be able to take advantage of dips in the noise levels, similar to participants with normal hearing. Although children required a more favorable signal-to-noise ratio than adults for both unmodulated and modulated noise, masking release was not statistically different. However, the ability to detect a difference may have been limited by the small amount of masking release observed.

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Effects of Removing Low-Frequency Electric Information on Speech Perception With Bimodal Hearing

Purpose
The objective was to determine whether speech perception could be improved for bimodal listeners (those using a cochlear implant [CI] in one ear and hearing aid in the contralateral ear) by removing low-frequency information provided by the CI, thereby reducing acoustic–electric overlap.
Method
Subjects were adult CI subjects with at least 1 year of CI experience. Nine subjects were evaluated in the CI-only condition (control condition), and 26 subjects were evaluated in the bimodal condition. CIs were programmed with 4 experimental programs in which the low cutoff frequency (LCF) was progressively raised. Speech perception was evaluated using Consonant-Nucleus-Consonant words in quiet, AzBio sentences in background babble, and spondee words in background babble.
Results
The CI-only group showed decreased speech perception in both quiet and noise as the LCF was raised. Bimodal subjects with better hearing in the hearing aid ear ( 60 dB HL at 250 and 500 Hz) performed similarly to the CI-only group.
Conclusions
These findings suggest that reducing low-frequency overlap of the CI and contralateral hearing aid may improve performance in quiet for some bimodal listeners with better hearing.

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Masking Release in Children and Adults With Hearing Loss When Using Amplification

Purpose
This study compared masking release for adults and children with normal hearing and hearing loss. For the participants with hearing loss, masking release using simulated hearing aid amplification with 2 different compression speeds (slow, fast) was compared.
Method
Sentence recognition in unmodulated noise was compared with recognition in modulated noise (masking release). Recognition was measured for participants with hearing loss using individualized amplification via the hearing-aid simulator.
Results
Adults with hearing loss showed greater masking release than the children with hearing loss. Average masking release was small (1 dB) and did not depend on hearing status. Masking release was comparable for slow and fast compression.
Conclusions
The use of amplification in this study contrasts with previous studies that did not use amplification. The results suggest that when differences in audibility are reduced, participants with hearing loss may be able to take advantage of dips in the noise levels, similar to participants with normal hearing. Although children required a more favorable signal-to-noise ratio than adults for both unmodulated and modulated noise, masking release was not statistically different. However, the ability to detect a difference may have been limited by the small amount of masking release observed.

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Response of the human tympanic membrane to transient acoustic and mechanical stimuli

Publication date: Available online 12 February 2016
Source:Hearing Research
Author(s): Payam Razavi, Michael E. Ravicz, Ivo Dobrev, Jeffrey Tao Cheng, Cosme Furlong, John J. Rosowski
The response of the tympanic membrane (TM) to transient environmental sounds and the contributions of different parts of the TM to middle-ear sound transmission were investigated by measuring the TM response to global transients (acoustic clicks) and to local transients (mechanical impulses) applied to the umbo and various locations on the TM. A lightly-fixed human temporal bone was prepared by removing the ear canal, inner ear, and stapes, leaving the incus, malleus, and TM intact. Motion of nearly the entire TM was measured by a digital holography system with a high speed camera at a rate of 42 000 frames per second, giving a temporal resolution of <24 μs for the duration of the TM response. The entire TM responded nearly instantaneously to acoustic transient stimuli, though the peak displacement and decay time constant varied with location. With local mechanical transients, the TM responded first locally at the site of stimulation, and the response spread approximately symmetrically and circumferentially around the umbo and manubrium. Acoustic and mechanical transients provide distinct and complementary stimuli for the study of TM response. Spatial variations in decay and rate of spread of response imply local variations in TM stiffness, mass, and damping.

Graphical abstract

image


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Response of the human tympanic membrane to transient acoustic and mechanical stimuli

Publication date: Available online 12 February 2016
Source:Hearing Research
Author(s): Payam Razavi, Michael E. Ravicz, Ivo Dobrev, Jeffrey Tao Cheng, Cosme Furlong, John J. Rosowski
The response of the tympanic membrane (TM) to transient environmental sounds and the contributions of different parts of the TM to middle-ear sound transmission were investigated by measuring the TM response to global transients (acoustic clicks) and to local transients (mechanical impulses) applied to the umbo and various locations on the TM. A lightly-fixed human temporal bone was prepared by removing the ear canal, inner ear, and stapes, leaving the incus, malleus, and TM intact. Motion of nearly the entire TM was measured by a digital holography system with a high speed camera at a rate of 42 000 frames per second, giving a temporal resolution of <24 μs for the duration of the TM response. The entire TM responded nearly instantaneously to acoustic transient stimuli, though the peak displacement and decay time constant varied with location. With local mechanical transients, the TM responded first locally at the site of stimulation, and the response spread approximately symmetrically and circumferentially around the umbo and manubrium. Acoustic and mechanical transients provide distinct and complementary stimuli for the study of TM response. Spatial variations in decay and rate of spread of response imply local variations in TM stiffness, mass, and damping.

Graphical abstract

image


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Response of the human tympanic membrane to transient acoustic and mechanical stimuli

Publication date: Available online 12 February 2016
Source:Hearing Research
Author(s): Payam Razavi, Michael E. Ravicz, Ivo Dobrev, Jeffrey Tao Cheng, Cosme Furlong, John J. Rosowski
The response of the tympanic membrane (TM) to transient environmental sounds and the contributions of different parts of the TM to middle-ear sound transmission were investigated by measuring the TM response to global transients (acoustic clicks) and to local transients (mechanical impulses) applied to the umbo and various locations on the TM. A lightly-fixed human temporal bone was prepared by removing the ear canal, inner ear, and stapes, leaving the incus, malleus, and TM intact. Motion of nearly the entire TM was measured by a digital holography system with a high speed camera at a rate of 42 000 frames per second, giving a temporal resolution of <24 μs for the duration of the TM response. The entire TM responded nearly instantaneously to acoustic transient stimuli, though the peak displacement and decay time constant varied with location. With local mechanical transients, the TM responded first locally at the site of stimulation, and the response spread approximately symmetrically and circumferentially around the umbo and manubrium. Acoustic and mechanical transients provide distinct and complementary stimuli for the study of TM response. Spatial variations in decay and rate of spread of response imply local variations in TM stiffness, mass, and damping.

Graphical abstract

image


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Family quality of life among families with a child who has a severe neurodevelopmental disability: Impact of family and child socio-demographic factors.

Family quality of life among families with a child who has a severe neurodevelopmental disability: Impact of family and child socio-demographic factors.

Res Dev Disabil. 2016 Feb 9;53-54:95-106

Authors: Schertz M, Karni-Visel Y, Tamir A, Genizi J, Roth D

Abstract
We aimed to examine family quality of life (FQOL) of Northern Israeli families having a child with a severe neurodevelopmental disability and its relation to socio-demographics. The cohort included caregivers of 70 children ages (mean±standard deviation) 5.36±3.53 years. Families were two-parent (85.7%), lived in the periphery (67.1%) and included Jews (60%), Muslims (18.6%), Druze (14.3%) and Christians (7.1%). Religiosity included: secular (38.6%), traditional (31.4%), religious (30%). Children's diagnosis included autistic spectrum disorder (41.4%), intellectual disability (21.4%), cerebral palsy (17.1%), genetic syndromes (17.1%) and sensorineural hearing loss (2.9%). Degree of support (1-minimal,5-greatest) required by the child was 3.67±1.28 for physical and 3.49±1.36 for communication. Primary caregivers completed the FQOL Survey. Domain scores were highest for family relations and lowest for financial well-being. Dimension scores were highest for importance and lowest for opportunities. Overall FQOL approximated average. Jewish families and residents of a major urban area reported higher and more religious families reported lower overall FQOL. Regression analysis found ethnicity contributing to overall FQOL and domain scores with residence contributing to support from services. Ethnicity and child dependence contributed to dimension scores. Northern Israeli families having a child with a severe neurodevelopmental disability report average FQOL scores. However, family and child dependence characteristics affect FQOL scores. Professionals working with these families should consider FQOL information when making recommendations.

PMID: 26871463 [PubMed - as supplied by publisher]



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A Novel Splicing Mutation Identified in a Chinese Family with X-linked Alport Syndrome Using Targeted Next-Generation Sequencing.

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A Novel Splicing Mutation Identified in a Chinese Family with X-linked Alport Syndrome Using Targeted Next-Generation Sequencing.

Genet Test Mol Biomarkers. 2016 Feb 11;

Authors: Chen C, Lu CX, Wang Q, Cao LH, Luo Y, Zhang X

Abstract
AIMS: Alport syndrome (AS) is a genetically heterogeneous disorder, characterized by hematuria, progressive renal failure, sensorineural hearing loss, and ocular abnormalities caused by mutations in the COL4A3, COL4A4, and COL4A5 genes. The aim of this study was to identify underlying mutations in individuals from a Chinese family with X-linked AS.
METHODS: We performed targeted next-generation sequencing (NGS) to identify mutations associated with AS. The results were processed and visualized using an Integrated Genomics Viewer software. The most likely disease-causing variants were identified and confirmed by Sanger sequencing of reverse transcription-polymerase chain reaction products.
RESULTS: Visual inspection using Integrative Genomics Viewer software found that COL4A5 exon 10 was not covered by the disease panel, while coverage of exons 4, 17, 20, 21, 37, and 45 was incomplete. Sanger sequencing of these regions identified a novel splice-site mutation in intron 9 (c.547-3C>A) of the COL4A5 gene. Subsequent cDNA analysis revealed that c.547-3C>A led to skipping of exon 10, which resulted in an in-frame deletion of 21 amino acids from the α5 chain of type IV collagen.
CONCLUSION: We determined the molecular basis of AS in a Chinese family by targeted NGS and cDNA analysis. This is the first report of the novel c.547-3C>A splicing mutation in the collagen domain of COL4A5 gene.

PMID: 26866448 [PubMed - as supplied by publisher]



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Self-reports versus parental perceptions of health-related quality of life among deaf children and adolescents.

http:--highwire.stanford.edu-icons-exter Related Articles

Self-reports versus parental perceptions of health-related quality of life among deaf children and adolescents.

J Deaf Stud Deaf Educ. 2015 Jul;20(3):275-82

Authors: Pardo-Guijarro MJ, Martínez-Andrés M, Notario-Pacheco B, Solera-Martínez M, Sánchez-López M, Martínez-Vizcaíno V

Abstract
The aim of this study was to assess the agreement between deaf children's and adolescents' self-ratings of health-related quality of life (HRQoL) and their parents' proxy reports. This observational cross-sectional study included 114 deaf 8- to 18-years-old students and proxy family members. HRQoL was measured using the KIDSCREEN-27 questionnaire, which was adapted to Spanish sign language for children, with a written version for parents. Respondents completed a self-administered paper questionnaire. Parents' and children's mean scores differences were not significant, except for the "Autonomy and Parents" and "Peers and Social Support" dimensions. Children aged 8-11 years scored higher in some domains of QoL compared to those aged 12-18 years. The level of agreement between children/adolescents' and parents/proxies' responses was acceptable, except for the dimension "Autonomy and Parents." Overall, deaf children/adolescents' self-ratings of HRQoL did not differ from their parents' proxy reports; however, differences were found in the dimensions that explored the quality of the interaction of children/adolescents and parents, the perceived level of autonomy, and social relations and support.

PMID: 25986604 [PubMed - indexed for MEDLINE]



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The effect of fluctuating maskers on speech understanding of high-performing cochlear implant users.

Related Articles

The effect of fluctuating maskers on speech understanding of high-performing cochlear implant users.

Int J Audiol. 2016 Feb 10;:1-10

Authors: Zirn S, Polterauer D, Keller S, Hemmert W

Abstract
OBJECTIVE: The present study evaluated whether the poorer baseline performance of cochlear implant (CI) users or the technical and/or physiological properties of CI stimulation are responsible for the absence of masking release.
DESIGN: This study measured speech reception thresholds (SRTs) in continuous and modulated noise as a function of signal to noise ratio (SNR).
STUDY SAMPLE: A total of 24 subjects participated: 12 normal-hearing (NH) listeners and 12 subjects provided with recent MED-EL CI systems.
RESULTS: The mean SRT of CI users in continuous noise was -3.0 ± 1.5 dB SNR (mean ± SEM), while the normal-hearing group reached -5.9 ± 0.8 dB SNR. In modulated noise, the difference across groups increased considerably. For CI users, the mean SRT worsened to -1.4 ± 2.3 dB SNR, while it improved for normal-hearing listeners to -18.9 ± 3.8 dB SNR.
CONCLUSIONS: The detrimental effect of fluctuating maskers on SRTs in CI users shown by prior studies was confirmed by the current study. Concluding, the absence of masking release is mainly caused by the technical and/or physiological properties of CI stimulation, not just the poorer baseline performance of many CI users compared to normal-hearing subjects. Speech understanding in modulated noise was more robust in CI users who had a relatively large electrical dynamic range.

PMID: 26865377 [PubMed - as supplied by publisher]



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The effect of fluctuating maskers on speech understanding of high-performing cochlear implant users.

Related Articles

The effect of fluctuating maskers on speech understanding of high-performing cochlear implant users.

Int J Audiol. 2016 Feb 10;:1-10

Authors: Zirn S, Polterauer D, Keller S, Hemmert W

Abstract
OBJECTIVE: The present study evaluated whether the poorer baseline performance of cochlear implant (CI) users or the technical and/or physiological properties of CI stimulation are responsible for the absence of masking release.
DESIGN: This study measured speech reception thresholds (SRTs) in continuous and modulated noise as a function of signal to noise ratio (SNR).
STUDY SAMPLE: A total of 24 subjects participated: 12 normal-hearing (NH) listeners and 12 subjects provided with recent MED-EL CI systems.
RESULTS: The mean SRT of CI users in continuous noise was -3.0 ± 1.5 dB SNR (mean ± SEM), while the normal-hearing group reached -5.9 ± 0.8 dB SNR. In modulated noise, the difference across groups increased considerably. For CI users, the mean SRT worsened to -1.4 ± 2.3 dB SNR, while it improved for normal-hearing listeners to -18.9 ± 3.8 dB SNR.
CONCLUSIONS: The detrimental effect of fluctuating maskers on SRTs in CI users shown by prior studies was confirmed by the current study. Concluding, the absence of masking release is mainly caused by the technical and/or physiological properties of CI stimulation, not just the poorer baseline performance of many CI users compared to normal-hearing subjects. Speech understanding in modulated noise was more robust in CI users who had a relatively large electrical dynamic range.

PMID: 26865377 [PubMed - as supplied by publisher]



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The effect of fluctuating maskers on speech understanding of high-performing cochlear implant users.

Related Articles

The effect of fluctuating maskers on speech understanding of high-performing cochlear implant users.

Int J Audiol. 2016 Feb 10;:1-10

Authors: Zirn S, Polterauer D, Keller S, Hemmert W

Abstract
OBJECTIVE: The present study evaluated whether the poorer baseline performance of cochlear implant (CI) users or the technical and/or physiological properties of CI stimulation are responsible for the absence of masking release.
DESIGN: This study measured speech reception thresholds (SRTs) in continuous and modulated noise as a function of signal to noise ratio (SNR).
STUDY SAMPLE: A total of 24 subjects participated: 12 normal-hearing (NH) listeners and 12 subjects provided with recent MED-EL CI systems.
RESULTS: The mean SRT of CI users in continuous noise was -3.0 ± 1.5 dB SNR (mean ± SEM), while the normal-hearing group reached -5.9 ± 0.8 dB SNR. In modulated noise, the difference across groups increased considerably. For CI users, the mean SRT worsened to -1.4 ± 2.3 dB SNR, while it improved for normal-hearing listeners to -18.9 ± 3.8 dB SNR.
CONCLUSIONS: The detrimental effect of fluctuating maskers on SRTs in CI users shown by prior studies was confirmed by the current study. Concluding, the absence of masking release is mainly caused by the technical and/or physiological properties of CI stimulation, not just the poorer baseline performance of many CI users compared to normal-hearing subjects. Speech understanding in modulated noise was more robust in CI users who had a relatively large electrical dynamic range.

PMID: 26865377 [PubMed - as supplied by publisher]



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The effect of fluctuating maskers on speech understanding of high-performing cochlear implant users.

Related Articles

The effect of fluctuating maskers on speech understanding of high-performing cochlear implant users.

Int J Audiol. 2016 Feb 10;:1-10

Authors: Zirn S, Polterauer D, Keller S, Hemmert W

Abstract
OBJECTIVE: The present study evaluated whether the poorer baseline performance of cochlear implant (CI) users or the technical and/or physiological properties of CI stimulation are responsible for the absence of masking release.
DESIGN: This study measured speech reception thresholds (SRTs) in continuous and modulated noise as a function of signal to noise ratio (SNR).
STUDY SAMPLE: A total of 24 subjects participated: 12 normal-hearing (NH) listeners and 12 subjects provided with recent MED-EL CI systems.
RESULTS: The mean SRT of CI users in continuous noise was -3.0 ± 1.5 dB SNR (mean ± SEM), while the normal-hearing group reached -5.9 ± 0.8 dB SNR. In modulated noise, the difference across groups increased considerably. For CI users, the mean SRT worsened to -1.4 ± 2.3 dB SNR, while it improved for normal-hearing listeners to -18.9 ± 3.8 dB SNR.
CONCLUSIONS: The detrimental effect of fluctuating maskers on SRTs in CI users shown by prior studies was confirmed by the current study. Concluding, the absence of masking release is mainly caused by the technical and/or physiological properties of CI stimulation, not just the poorer baseline performance of many CI users compared to normal-hearing subjects. Speech understanding in modulated noise was more robust in CI users who had a relatively large electrical dynamic range.

PMID: 26865377 [PubMed - as supplied by publisher]



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Walking at the preferred stride frequency minimizes muscle activity

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Daniel M. Russell, Dylan T. Apatoczky
This study determined whether walking at the preferred stride frequency minimizes muscle activity compared with other cadences at the same speed. Anthropometric measurements were recorded from 10 subjects and used to estimate their predicted resonant stride frequency. The preferred walking speed and stride frequency were determined from freely adopted walking on a treadmill. For the experimental trials the treadmill was set at each individual's preferred walking speed. Participants walked for 6min at eight cadences prescribed by an auditory metronome: preferred stride frequency and −35, −25, −15, 0, +15, +25, +35% of predicted resonant stride frequency. Oxygen consumption was measured via gas analysis. Muscle activity of the right leg gastrocnemius (GA), tibialis anterior (TA), biceps femoris (BF) and rectus femoris (RF) muscles was recorded via electromyography (EMG). On average, participants preferred to walk with a stride frequency .07Hz lower than their predicted resonant stride frequency, however a strong positive correlation was observed between these variables. Stride frequency had a significant and large quadratic effect on VO2 (RLR2=.76), and activity of the GA (RLR2=.66), TA (RLR2=.83), BF (RLR2=.70) and RF (RLR2=.78) muscles. VO2, GA and TA activity were all minimal at the preferred stride frequency and increased for faster or slower cadences. BF and RF activity were minimal across a broad range of slow frequencies including the preferred stride frequency and increased for faster frequencies. The preferred stride frequency that humans readily adopt during walking minimizes the activation of the GA, TA, BF and RF muscles, which in turn minimizes the overall metabolic cost.



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Walking Beyond Preferred Transition Speed Increases Muscle Activations with a Shift from Inverted Pendulum to Spring Mass Model in Lower Extremity

Publication date: Available online 12 February 2016
Source:Gait & Posture
Author(s): Yo Shih, Yi-Chun Chen, Yin-Shin Lee, Ming-Sheng Chan, Tzyy-Yuang Shiang
BackgroundThe triggers for the transition of gait from walking to running during increasing speed locomotion have been attributed to an energy conservation strategy or a relief of excessive muscle activation. Walking beyond the preferred transition speed (PTS) has been proposed as an exercise protocol for boosting energy consumption. However, the biomechanical factors involved while this protocol is used have not been investigated. Thus, this study investigated the difference between walking and running below, during, and beyond the PTS from a biomechanical perspective.MethodsSixteen healthy male participants were recruited. After determination of their PTS, five speeds of walking and running were defined. Kinematic data, including center-of-mass (COM) displacement, COM acceleration, and electromyography (EMG) data of rectus femoris (RF), biceps femoris, gastrocnemius (GAS), and tibialis anterior were collected at the five speeds for both walking and running.ResultThe vertical COM displacement and acceleration in running were significantly larger than those in walking at all five speeds (p<0.05). EMG signals of the two antigravity muscles, RF and GAS, demonstrated a significant higher activation in walking than that in running at the speed beyond PTS (p<0.05).ConclusionThe larger energy consumption in walking than that in running beyond the PTS may be attributed to the high activation of lower-extremity muscles. The smaller vertical COM displacements and accelerations exhibited when participants walked beyond the PTS rather than ran did not indicate adverse effects of using walking beyond the PTS as an exercise prescription for boosting energy consumption.



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Walking at the preferred stride frequency minimizes muscle activity

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Daniel M. Russell, Dylan T. Apatoczky
This study determined whether walking at the preferred stride frequency minimizes muscle activity compared with other cadences at the same speed. Anthropometric measurements were recorded from 10 subjects and used to estimate their predicted resonant stride frequency. The preferred walking speed and stride frequency were determined from freely adopted walking on a treadmill. For the experimental trials the treadmill was set at each individual's preferred walking speed. Participants walked for 6min at eight cadences prescribed by an auditory metronome: preferred stride frequency and −35, −25, −15, 0, +15, +25, +35% of predicted resonant stride frequency. Oxygen consumption was measured via gas analysis. Muscle activity of the right leg gastrocnemius (GA), tibialis anterior (TA), biceps femoris (BF) and rectus femoris (RF) muscles was recorded via electromyography (EMG). On average, participants preferred to walk with a stride frequency .07Hz lower than their predicted resonant stride frequency, however a strong positive correlation was observed between these variables. Stride frequency had a significant and large quadratic effect on VO2 (RLR2=.76), and activity of the GA (RLR2=.66), TA (RLR2=.83), BF (RLR2=.70) and RF (RLR2=.78) muscles. VO2, GA and TA activity were all minimal at the preferred stride frequency and increased for faster or slower cadences. BF and RF activity were minimal across a broad range of slow frequencies including the preferred stride frequency and increased for faster frequencies. The preferred stride frequency that humans readily adopt during walking minimizes the activation of the GA, TA, BF and RF muscles, which in turn minimizes the overall metabolic cost.



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Walking Beyond Preferred Transition Speed Increases Muscle Activations with a Shift from Inverted Pendulum to Spring Mass Model in Lower Extremity

Publication date: Available online 12 February 2016
Source:Gait & Posture
Author(s): Yo Shih, Yi-Chun Chen, Yin-Shin Lee, Ming-Sheng Chan, Tzyy-Yuang Shiang
BackgroundThe triggers for the transition of gait from walking to running during increasing speed locomotion have been attributed to an energy conservation strategy or a relief of excessive muscle activation. Walking beyond the preferred transition speed (PTS) has been proposed as an exercise protocol for boosting energy consumption. However, the biomechanical factors involved while this protocol is used have not been investigated. Thus, this study investigated the difference between walking and running below, during, and beyond the PTS from a biomechanical perspective.MethodsSixteen healthy male participants were recruited. After determination of their PTS, five speeds of walking and running were defined. Kinematic data, including center-of-mass (COM) displacement, COM acceleration, and electromyography (EMG) data of rectus femoris (RF), biceps femoris, gastrocnemius (GAS), and tibialis anterior were collected at the five speeds for both walking and running.ResultThe vertical COM displacement and acceleration in running were significantly larger than those in walking at all five speeds (p<0.05). EMG signals of the two antigravity muscles, RF and GAS, demonstrated a significant higher activation in walking than that in running at the speed beyond PTS (p<0.05).ConclusionThe larger energy consumption in walking than that in running beyond the PTS may be attributed to the high activation of lower-extremity muscles. The smaller vertical COM displacements and accelerations exhibited when participants walked beyond the PTS rather than ran did not indicate adverse effects of using walking beyond the PTS as an exercise prescription for boosting energy consumption.



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Walking at the preferred stride frequency minimizes muscle activity

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Daniel M. Russell, Dylan T. Apatoczky
This study determined whether walking at the preferred stride frequency minimizes muscle activity compared with other cadences at the same speed. Anthropometric measurements were recorded from 10 subjects and used to estimate their predicted resonant stride frequency. The preferred walking speed and stride frequency were determined from freely adopted walking on a treadmill. For the experimental trials the treadmill was set at each individual's preferred walking speed. Participants walked for 6min at eight cadences prescribed by an auditory metronome: preferred stride frequency and −35, −25, −15, 0, +15, +25, +35% of predicted resonant stride frequency. Oxygen consumption was measured via gas analysis. Muscle activity of the right leg gastrocnemius (GA), tibialis anterior (TA), biceps femoris (BF) and rectus femoris (RF) muscles was recorded via electromyography (EMG). On average, participants preferred to walk with a stride frequency .07Hz lower than their predicted resonant stride frequency, however a strong positive correlation was observed between these variables. Stride frequency had a significant and large quadratic effect on VO2 (RLR2=.76), and activity of the GA (RLR2=.66), TA (RLR2=.83), BF (RLR2=.70) and RF (RLR2=.78) muscles. VO2, GA and TA activity were all minimal at the preferred stride frequency and increased for faster or slower cadences. BF and RF activity were minimal across a broad range of slow frequencies including the preferred stride frequency and increased for faster frequencies. The preferred stride frequency that humans readily adopt during walking minimizes the activation of the GA, TA, BF and RF muscles, which in turn minimizes the overall metabolic cost.



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Walking Beyond Preferred Transition Speed Increases Muscle Activations with a Shift from Inverted Pendulum to Spring Mass Model in Lower Extremity

Publication date: Available online 12 February 2016
Source:Gait & Posture
Author(s): Yo Shih, Yi-Chun Chen, Yin-Shin Lee, Ming-Sheng Chan, Tzyy-Yuang Shiang
BackgroundThe triggers for the transition of gait from walking to running during increasing speed locomotion have been attributed to an energy conservation strategy or a relief of excessive muscle activation. Walking beyond the preferred transition speed (PTS) has been proposed as an exercise protocol for boosting energy consumption. However, the biomechanical factors involved while this protocol is used have not been investigated. Thus, this study investigated the difference between walking and running below, during, and beyond the PTS from a biomechanical perspective.MethodsSixteen healthy male participants were recruited. After determination of their PTS, five speeds of walking and running were defined. Kinematic data, including center-of-mass (COM) displacement, COM acceleration, and electromyography (EMG) data of rectus femoris (RF), biceps femoris, gastrocnemius (GAS), and tibialis anterior were collected at the five speeds for both walking and running.ResultThe vertical COM displacement and acceleration in running were significantly larger than those in walking at all five speeds (p<0.05). EMG signals of the two antigravity muscles, RF and GAS, demonstrated a significant higher activation in walking than that in running at the speed beyond PTS (p<0.05).ConclusionThe larger energy consumption in walking than that in running beyond the PTS may be attributed to the high activation of lower-extremity muscles. The smaller vertical COM displacements and accelerations exhibited when participants walked beyond the PTS rather than ran did not indicate adverse effects of using walking beyond the PTS as an exercise prescription for boosting energy consumption.



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Effects of Negative Middle Ear Pressure on Wideband Acoustic Immittance in Normal-Hearing Adults.

Objectives: Wideband acoustic immittance (WAI) measurements are capable of quantifying middle ear performance over a wide range of frequencies relevant to human hearing. Static pressure in the middle ear cavity affects sound transmission to the cochlea, but few datasets exist to quantify the relationship between middle ear transmission and the static pressure. In this study, WAI measurements of normal ears are analyzed in both negative middle ear pressure (NMEP) and ambient middle ear pressure (AMEP) conditions, with a focus on the effects of NMEP in individual ears. Design: Eight subjects with normal middle ear function were trained to induce consistent NMEPs, quantified by the tympanic peak pressure (TPP) and WAI. The effects of NMEP on the wideband power absorbance level are analyzed for individual ears. Complex (magnitude and phase) WAI quantities at the tympanic membrane (TM) are studied by removing the delay due to the residual ear canal (REC) volume between the probe tip and the TM. WAI results are then analyzed using a simplified classical model of the middle ear. Results: For the 8 ears presented here, NMEP has the largest and most significant effect across ears from 0.8 to 1.9 kHz, resulting in reduced power absorbance by the middle ear and cochlea. On average, NMEP causes a decrease in the power absorbance level for low- to mid-frequencies, and a small increase above about 4 kHz. The effects of NMEP on WAI quantities, including the absorbance level and TM impedance, vary considerably across ears. The complex WAI at the TM and fitted model parameters show that NMEP causes a decrease in the aggregate compliance at the TM. Estimated REC delays show little to no dependence on NMEP. Conclusions: In agreement with previous results, these data show that the power absorbance level is most sensitive to NMEP around 1 kHz. The REC effect is removed from WAI measurements, allowing for direct estimation of complex WAI at the TM. These estimates show NMEP effects consistent with an increased stiffness in the middle ear, which could originate from the TM, tensor tympani, annular ligament, or other middle ear structures. Model results quantify this nonlinear, stiffness-related change in a systematic way, that is not dependent on averaging WAI results in frequency bands. Given the variability of pressure effects, likely related to intersubject variability at AMEP, TPP is not a strong predictor of change in WAI at the TM. More data and modeling will be needed to better quantify the relationship between NMEP, WAI, and middle ear transmission. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.

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Using the Digits-In-Noise Test to Estimate Age-Related Hearing Loss.

Objective: Age-related hearing loss is common in the elderly population. Timely detection and targeted counseling can lead to adequate treatment with hearing aids. The Digits-In-Noise (DIN) test was developed as a relatively simple test to assess hearing acuity. It is a potentially powerful test for the screening of large populations, including the elderly. However, until to date, no sensitivity or specificity rates for detecting hearing loss were reported in a general elderly population. The purpose of this study was to evaluate the ability of the DIN test to screen for mild and moderate hearing loss in the elderly. Design: Data of pure-tone audiometry and the DIN test were collected from 3327 adults aged above 50 (mean: 65), as part of the Rotterdam Study, a large population-based cohort study. Sensitivity and specificity of the DIN test for detecting hearing loss were calculated by comparing speech reception threshold (SRT) with pure-tone average threshold at 0.5, 1, 2, and 4 kHz (PTA0.5,1,2,4). Receiver operating characteristics were calculated for detecting >20 and >35 dB HL average hearing loss at the best ear. Results: Hearing loss varied greatly between subjects and, as expected, increased with age. High frequencies and men were more severely affected. A strong correlation (R = 0.80, p

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Effects of Negative Middle Ear Pressure on Wideband Acoustic Immittance in Normal-Hearing Adults.

Objectives: Wideband acoustic immittance (WAI) measurements are capable of quantifying middle ear performance over a wide range of frequencies relevant to human hearing. Static pressure in the middle ear cavity affects sound transmission to the cochlea, but few datasets exist to quantify the relationship between middle ear transmission and the static pressure. In this study, WAI measurements of normal ears are analyzed in both negative middle ear pressure (NMEP) and ambient middle ear pressure (AMEP) conditions, with a focus on the effects of NMEP in individual ears. Design: Eight subjects with normal middle ear function were trained to induce consistent NMEPs, quantified by the tympanic peak pressure (TPP) and WAI. The effects of NMEP on the wideband power absorbance level are analyzed for individual ears. Complex (magnitude and phase) WAI quantities at the tympanic membrane (TM) are studied by removing the delay due to the residual ear canal (REC) volume between the probe tip and the TM. WAI results are then analyzed using a simplified classical model of the middle ear. Results: For the 8 ears presented here, NMEP has the largest and most significant effect across ears from 0.8 to 1.9 kHz, resulting in reduced power absorbance by the middle ear and cochlea. On average, NMEP causes a decrease in the power absorbance level for low- to mid-frequencies, and a small increase above about 4 kHz. The effects of NMEP on WAI quantities, including the absorbance level and TM impedance, vary considerably across ears. The complex WAI at the TM and fitted model parameters show that NMEP causes a decrease in the aggregate compliance at the TM. Estimated REC delays show little to no dependence on NMEP. Conclusions: In agreement with previous results, these data show that the power absorbance level is most sensitive to NMEP around 1 kHz. The REC effect is removed from WAI measurements, allowing for direct estimation of complex WAI at the TM. These estimates show NMEP effects consistent with an increased stiffness in the middle ear, which could originate from the TM, tensor tympani, annular ligament, or other middle ear structures. Model results quantify this nonlinear, stiffness-related change in a systematic way, that is not dependent on averaging WAI results in frequency bands. Given the variability of pressure effects, likely related to intersubject variability at AMEP, TPP is not a strong predictor of change in WAI at the TM. More data and modeling will be needed to better quantify the relationship between NMEP, WAI, and middle ear transmission. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.

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Using the Digits-In-Noise Test to Estimate Age-Related Hearing Loss.

Objective: Age-related hearing loss is common in the elderly population. Timely detection and targeted counseling can lead to adequate treatment with hearing aids. The Digits-In-Noise (DIN) test was developed as a relatively simple test to assess hearing acuity. It is a potentially powerful test for the screening of large populations, including the elderly. However, until to date, no sensitivity or specificity rates for detecting hearing loss were reported in a general elderly population. The purpose of this study was to evaluate the ability of the DIN test to screen for mild and moderate hearing loss in the elderly. Design: Data of pure-tone audiometry and the DIN test were collected from 3327 adults aged above 50 (mean: 65), as part of the Rotterdam Study, a large population-based cohort study. Sensitivity and specificity of the DIN test for detecting hearing loss were calculated by comparing speech reception threshold (SRT) with pure-tone average threshold at 0.5, 1, 2, and 4 kHz (PTA0.5,1,2,4). Receiver operating characteristics were calculated for detecting >20 and >35 dB HL average hearing loss at the best ear. Results: Hearing loss varied greatly between subjects and, as expected, increased with age. High frequencies and men were more severely affected. A strong correlation (R = 0.80, p

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Effects of Negative Middle Ear Pressure on Wideband Acoustic Immittance in Normal-Hearing Adults.

Objectives: Wideband acoustic immittance (WAI) measurements are capable of quantifying middle ear performance over a wide range of frequencies relevant to human hearing. Static pressure in the middle ear cavity affects sound transmission to the cochlea, but few datasets exist to quantify the relationship between middle ear transmission and the static pressure. In this study, WAI measurements of normal ears are analyzed in both negative middle ear pressure (NMEP) and ambient middle ear pressure (AMEP) conditions, with a focus on the effects of NMEP in individual ears. Design: Eight subjects with normal middle ear function were trained to induce consistent NMEPs, quantified by the tympanic peak pressure (TPP) and WAI. The effects of NMEP on the wideband power absorbance level are analyzed for individual ears. Complex (magnitude and phase) WAI quantities at the tympanic membrane (TM) are studied by removing the delay due to the residual ear canal (REC) volume between the probe tip and the TM. WAI results are then analyzed using a simplified classical model of the middle ear. Results: For the 8 ears presented here, NMEP has the largest and most significant effect across ears from 0.8 to 1.9 kHz, resulting in reduced power absorbance by the middle ear and cochlea. On average, NMEP causes a decrease in the power absorbance level for low- to mid-frequencies, and a small increase above about 4 kHz. The effects of NMEP on WAI quantities, including the absorbance level and TM impedance, vary considerably across ears. The complex WAI at the TM and fitted model parameters show that NMEP causes a decrease in the aggregate compliance at the TM. Estimated REC delays show little to no dependence on NMEP. Conclusions: In agreement with previous results, these data show that the power absorbance level is most sensitive to NMEP around 1 kHz. The REC effect is removed from WAI measurements, allowing for direct estimation of complex WAI at the TM. These estimates show NMEP effects consistent with an increased stiffness in the middle ear, which could originate from the TM, tensor tympani, annular ligament, or other middle ear structures. Model results quantify this nonlinear, stiffness-related change in a systematic way, that is not dependent on averaging WAI results in frequency bands. Given the variability of pressure effects, likely related to intersubject variability at AMEP, TPP is not a strong predictor of change in WAI at the TM. More data and modeling will be needed to better quantify the relationship between NMEP, WAI, and middle ear transmission. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.

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Using the Digits-In-Noise Test to Estimate Age-Related Hearing Loss.

Objective: Age-related hearing loss is common in the elderly population. Timely detection and targeted counseling can lead to adequate treatment with hearing aids. The Digits-In-Noise (DIN) test was developed as a relatively simple test to assess hearing acuity. It is a potentially powerful test for the screening of large populations, including the elderly. However, until to date, no sensitivity or specificity rates for detecting hearing loss were reported in a general elderly population. The purpose of this study was to evaluate the ability of the DIN test to screen for mild and moderate hearing loss in the elderly. Design: Data of pure-tone audiometry and the DIN test were collected from 3327 adults aged above 50 (mean: 65), as part of the Rotterdam Study, a large population-based cohort study. Sensitivity and specificity of the DIN test for detecting hearing loss were calculated by comparing speech reception threshold (SRT) with pure-tone average threshold at 0.5, 1, 2, and 4 kHz (PTA0.5,1,2,4). Receiver operating characteristics were calculated for detecting >20 and >35 dB HL average hearing loss at the best ear. Results: Hearing loss varied greatly between subjects and, as expected, increased with age. High frequencies and men were more severely affected. A strong correlation (R = 0.80, p

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