The Effect of Short-Term Auditory Training on Speech in Noise Perception and Cortical Auditory Evoked Potentials in Adults with Cochlear Implants

Semin Hear 2016; 37: 084-098
DOI: 10.1055/s-0035-1570335

This study investigated whether a short intensive psychophysical auditory training program is associated with speech perception benefits and changes in cortical auditory evoked potentials (CAEPs) in adult cochlear implant (CI) users. Ten adult implant recipients trained approximately 7 hours on psychophysical tasks (Gap-in-Noise Detection, Frequency Discrimination, Spectral Rippled Noise [SRN], Iterated Rippled Noise, Temporal Modulation). Speech performance was assessed before and after training using Lexical Neighborhood Test (LNT) words in quiet and in eight-speaker babble. CAEPs evoked by a natural speech stimulus /baba/ with varying syllable stress were assessed pre- and post-training, in quiet and in noise. SRN psychophysical thresholds showed a significant improvement (78% on average) over the training period, but performance on other psychophysical tasks did not change. LNT scores in noise improved significantly post-training by 11% on average compared with three pretraining baseline measures. N1P2 amplitude changed post-training for /baba/ in quiet (p = 0.005, visit 3 pretraining versus visit 4 post-training). CAEP changes did not correlate with behavioral measures. CI recipients' clinical records indicated a plateau in speech perception performance prior to participation in the study. A short period of intensive psychophysical training produced small but significant gains in speech perception in noise and spectral discrimination ability. There remain questions about the most appropriate type of training and the duration or dosage of training that provides the most robust outcomes for adults with CIs.
[...]

Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Article in Thieme eJournals:
Table of contents  |  Abstract  |  Full text

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Summary of the N1-P2 Cortical Auditory Evoked Potential to Estimate the Auditory Threshold in Adults

Semin Hear 2016; 37: 001-008
DOI: 10.1055/s-0035-1570334

This article introduces the cortical auditory evoked potential (CAEP) and describes the use of the N1-P2 response complex as an objective predictor of hearing threshold in adults and older children. The generators of the CAEP are discussed together with issues of maturation, subject factors, and stimuli and recording parameters for use in the clinic. The basic methods for response identification are outlined and suggestions are made for determining the CAEP threshold. Clinical applications are introduced and the accuracy of the CAEP as an estimator of hearing threshold is given. Finally, a case study provides an example of the technique in the context of medicolegal assessment.
[...]

Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Article in Thieme eJournals:
Table of contents  |  Abstract  |  Full text

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Cortical Auditory Evoked Potentials in (Un)aided Normal-Hearing and Hearing-Impaired Adults

Semin Hear 2016; 37: 009-024
DOI: 10.1055/s-0035-1570333

Cortical auditory evoked potentials (CAEPs) are influenced by the characteristics of the stimulus, including level and hearing aid gain. Previous studies have measured CAEPs aided and unaided in individuals with normal hearing. There is a significant difference between providing amplification to a person with normal hearing and a person with hearing loss. This study investigated this difference and the effects of stimulus signal-to-noise ratio (SNR) and audibility on the CAEP amplitude in a population with hearing loss. Twelve normal-hearing participants and 12 participants with a hearing loss participated in this study. Three speech sounds—/m/, /g/, and /t/—were presented in the free field. Unaided stimuli were presented at 55, 65, and 75 dB sound pressure level (SPL) and aided stimuli at 55 dB SPL with three different gains in steps of 10 dB. CAEPs were recorded and their amplitudes analyzed. Stimulus SNRs and audibility were determined. No significant effect of stimulus level or hearing aid gain was found in normal hearers. Conversely, a significant effect was found in hearing-impaired individuals. Audibility of the signal, which in some cases is determined by the signal level relative to threshold and in other cases by the SNR, is the dominant factor explaining changes in CAEP amplitude. CAEPs can potentially be used to assess the effects of hearing aid gain in hearing-impaired users.
[...]

Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

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Clinical Experience of Using Cortical Auditory Evoked Potentials in the Treatment of Infant Hearing Loss in Australia

Semin Hear 2016; 37: 036-052
DOI: 10.1055/s-0035-1570331

This article presents the clinical protocol that is currently being used within Australian Hearing for infant hearing aid evaluation using cortical auditory evoked potentials (CAEPs). CAEP testing is performed in the free field at two stimulus levels (65 dB sound pressure level [SPL], followed by 55 or 75 dB SPL) using three brief frequency-distinct speech sounds /m/, /ɡ/, and /t/, within a standard audiological appointment of up to 90 minutes. CAEP results are used to check or guide modifications of hearing aid fittings or to confirm unaided hearing capability. A retrospective review of 83 client files evaluated whether clinical practice aligned with the clinical protocol. It showed that most children could be assessed as part of their initial fitting program when they were identified as a priority for CAEP testing. Aided CAEPs were most commonly assessed within 8 weeks of the fitting. A survey of 32 pediatric audiologists provided information about their perception of cortical testing at Australian Hearing. The results indicated that clinical CAEP testing influenced audiologists' approach to rehabilitation and was well received by parents and that they were satisfied with the technique. Three case studies were selected to illustrate how CAEP testing can be used in a clinical environment. Overall, CAEP testing has been effectively integrated into the infant fitting program.
[...]

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Cortical Auditory Evoked Potentials Reveal Changes in Audibility with Nonlinear Frequency Compression in Hearing Aids for Children: Clinical Implications

Semin Hear 2016; 37: 025-035
DOI: 10.1055/s-0035-1570332

Hearing loss in children is detected soon after birth via newborn hearing screening. Procedures for early hearing assessment and hearing aid fitting are well established, but methods for evaluating the effectiveness of amplification for young children are limited. One promising approach to validating hearing aid fittings is to measure cortical auditory evoked potentials (CAEPs). This article provides first a brief overview of reports on the use of CAEPs for evaluation of hearing aids. Second, a study that measured CAEPs to evaluate nonlinear frequency compression (NLFC) in hearing aids for 27 children (between 6.1 and 16.8 years old) who have mild to severe hearing loss is reported. There was no significant difference in aided sensation level or the detection of CAEPs for /g/ between NLFC on and off conditions. The activation of NLFC was associated with a significant increase in aided sensation levels for /t/ and /s/. It also was associated with an increase in detection of CAEPs for /t/ and /s/. The findings support the use of CAEPs for checking audibility provided by hearing aids. Based on the current data, a clinical protocol for using CAEPs to validate audibility with amplification is presented.
[...]

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Change in Speech Perception and Auditory Evoked Potentials over Time after Unilateral Cochlear Implantation in Postlingually Deaf Adults

Semin Hear 2016; 37: 062-073
DOI: 10.1055/s-0035-1570329

Speech perception varies widely across cochlear implant (CI) users and typically improves over time after implantation. There is also some evidence for improved auditory evoked potentials (shorter latencies, larger amplitudes) after implantation but few longitudinal studies have examined the relationship between behavioral and evoked potential measures after implantation in postlingually deaf adults. The relationship between speech perception and auditory evoked potentials was investigated in newly implanted cochlear implant users from the day of implant activation to 9 months postimplantation, on five occasions, in 10 adults age 27 to 57 years who had been bilaterally profoundly deaf for 1 to 30 years prior to receiving a unilateral CI24 cochlear implant. Changes over time in middle latency response (MLR), mismatch negativity, and obligatory cortical auditory evoked potentials and word and sentence speech perception scores were examined. Speech perception improved significantly over the 9-month period. MLRs varied and showed no consistent change over time. Three participants aged in their 50s had absent MLRs. The pattern of change in N1 amplitudes over the five visits varied across participants. P2 area increased significantly for 1,000- and 4,000-Hz tones but not for 250 Hz. The greatest change in P2 area occurred after 6 months of implant experience. Although there was a trend for mismatch negativity peak latency to reduce and width to increase after 3 months of implant experience, there was considerable variability and these changes were not significant. Only 60% of participants had a detectable mismatch initially; this increased to 100% at 9 months. The continued change in P2 area over the period evaluated, with a trend for greater change for right hemisphere recordings, is consistent with the pattern of incremental change in speech perception scores over time. MLR, N1, and mismatch negativity changes were inconsistent and hence P2 may be a more robust measure of auditory plasticity in adult implant recipients. P2 was still improving at 9 months postimplantation. Future studies should explore longitudinal changes over a longer period.
[...]

Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Article in Thieme eJournals:
Table of contents  |  Abstract  |  Full text

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The Effect of Short-Term Auditory Training on Speech in Noise Perception and Cortical Auditory Evoked Potentials in Adults with Cochlear Implants

Semin Hear 2016; 37: 084-098
DOI: 10.1055/s-0035-1570335

This study investigated whether a short intensive psychophysical auditory training program is associated with speech perception benefits and changes in cortical auditory evoked potentials (CAEPs) in adult cochlear implant (CI) users. Ten adult implant recipients trained approximately 7 hours on psychophysical tasks (Gap-in-Noise Detection, Frequency Discrimination, Spectral Rippled Noise [SRN], Iterated Rippled Noise, Temporal Modulation). Speech performance was assessed before and after training using Lexical Neighborhood Test (LNT) words in quiet and in eight-speaker babble. CAEPs evoked by a natural speech stimulus /baba/ with varying syllable stress were assessed pre- and post-training, in quiet and in noise. SRN psychophysical thresholds showed a significant improvement (78% on average) over the training period, but performance on other psychophysical tasks did not change. LNT scores in noise improved significantly post-training by 11% on average compared with three pretraining baseline measures. N1P2 amplitude changed post-training for /baba/ in quiet (p = 0.005, visit 3 pretraining versus visit 4 post-training). CAEP changes did not correlate with behavioral measures. CI recipients' clinical records indicated a plateau in speech perception performance prior to participation in the study. A short period of intensive psychophysical training produced small but significant gains in speech perception in noise and spectral discrimination ability. There remain questions about the most appropriate type of training and the duration or dosage of training that provides the most robust outcomes for adults with CIs.
[...]

Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Article in Thieme eJournals:
Table of contents  |  Abstract  |  Full text

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Summary of the N1-P2 Cortical Auditory Evoked Potential to Estimate the Auditory Threshold in Adults

Semin Hear 2016; 37: 001-008
DOI: 10.1055/s-0035-1570334

This article introduces the cortical auditory evoked potential (CAEP) and describes the use of the N1-P2 response complex as an objective predictor of hearing threshold in adults and older children. The generators of the CAEP are discussed together with issues of maturation, subject factors, and stimuli and recording parameters for use in the clinic. The basic methods for response identification are outlined and suggestions are made for determining the CAEP threshold. Clinical applications are introduced and the accuracy of the CAEP as an estimator of hearing threshold is given. Finally, a case study provides an example of the technique in the context of medicolegal assessment.
[...]

Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Article in Thieme eJournals:
Table of contents  |  Abstract  |  Full text

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Channeling Your Inner Ear Potassium: K+ Channels in Vestibular Hair Cells

Publication date: Available online 4 February 2016
Source:Hearing Research
Author(s): Frances L. Meredith, Katherine J. Rennie
During development of vestibular hair cells, K⁺ conductances are acquired in a specific pattern. Functionally mature vestibular hair cells express different complements of K⁺ channels which uniquely shape the hair cell receptor potential and filtering properties. In amniote species, type I hair cells (HCI) have a large input conductance due to a ubiquitous low–voltage-activated K⁺ current that activates with slow sigmoidal kinetics at voltages negative to the membrane resting potential. In contrast type II hair cells (HCII) from mammalian and non-mammalian species have voltage-dependent outward K⁺ currents that activate rapidly at or above the resting membrane potential and show significant inactivation. A-type, delayed rectifier and calcium-activated K⁺ channels contribute to the outward K⁺ conductance and are present in varying proportions in HCII. In many species, K⁺ currents in HCII in peripheral locations of vestibular epithelia inactivate more than HCII in more central locations. Two types of inward rectifier currents have been described in both HCI and HCII. A rapidly activating K⁺-selective inward rectifier current (IK1, mediated by Kir2.1 channels) predominates in HCII in peripheral zones, whereas a slower mixed cation inward rectifier current (Ih), shows greater expression in HCII in central zones of vestibular epithelia. The implications for sensory coding of vestibular signals by different types of hair cells are discussed.



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Indication of Direct Acoustical Cochlea Stimulation in Comparison to Cochlear Implants

Publication date: Available online 4 February 2016
Source:Hearing Research
Author(s): Eugen Kludt, Andreas Büchner, Burkard Schwab, Thomas Lenarz, Hannes Maier
The new implantable hearing system Codacs™ was designed to close the treatment gap between active middle ear implants and cochlear implants in cases of severe-to-profound mixed hearing loss. The Codacs™ actuator is attached to conventional stapes prosthesis during the implantation and thereby provides acoustical stimulation through a stapedotomy to the cochlea. Cochlear implants (CIs) on the other hand are an established treatment option for profoundly deaf patients including mixed hearing losses that are possible candidates for the Codacs™.In this retrospective study, we compared the clinical outcome of 25 patients with the Codacs™ (≥3 month post-activation) to 54 CI patients (two years post-activation) with comparable pre-operative bone conduction (BC) thresholds that were potential candidates for both categories of devices. The word recognition score (Freiburg monosyllables test) in quiet was significantly (p < 0.05) better in the Codacs™ than in the corresponding CI patients for average pre-operative bone conduction below 60 dB HL and equal in patients with a pre-operative BC PTA between 60 and 70 dB HL. Speech in noise intelligibility (HSM sentences test at +10 dB SNR) was significantly (p < 0.001) better in Codacs™ (80 % median) than in CI patients (25 % median) in all tested groups.Our results indicate for patients with sufficient cochlear reserve that speech intelligibility in noise with the Codacs™ hearing implant is significantly better than with a CI. Further, results in Codacs™ were better predictable, encouraging the extension of the indication to patients with less cochlear reserve than reported here.



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Channeling Your Inner Ear Potassium: K+ Channels in Vestibular Hair Cells

Publication date: Available online 4 February 2016
Source:Hearing Research
Author(s): Frances L. Meredith, Katherine J. Rennie
During development of vestibular hair cells, K⁺ conductances are acquired in a specific pattern. Functionally mature vestibular hair cells express different complements of K⁺ channels which uniquely shape the hair cell receptor potential and filtering properties. In amniote species, type I hair cells (HCI) have a large input conductance due to a ubiquitous low–voltage-activated K⁺ current that activates with slow sigmoidal kinetics at voltages negative to the membrane resting potential. In contrast type II hair cells (HCII) from mammalian and non-mammalian species have voltage-dependent outward K⁺ currents that activate rapidly at or above the resting membrane potential and show significant inactivation. A-type, delayed rectifier and calcium-activated K⁺ channels contribute to the outward K⁺ conductance and are present in varying proportions in HCII. In many species, K⁺ currents in HCII in peripheral locations of vestibular epithelia inactivate more than HCII in more central locations. Two types of inward rectifier currents have been described in both HCI and HCII. A rapidly activating K⁺-selective inward rectifier current (IK1, mediated by Kir2.1 channels) predominates in HCII in peripheral zones, whereas a slower mixed cation inward rectifier current (Ih), shows greater expression in HCII in central zones of vestibular epithelia. The implications for sensory coding of vestibular signals by different types of hair cells are discussed.



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Indication of Direct Acoustical Cochlea Stimulation in Comparison to Cochlear Implants

Publication date: Available online 4 February 2016
Source:Hearing Research
Author(s): Eugen Kludt, Andreas Büchner, Burkard Schwab, Thomas Lenarz, Hannes Maier
The new implantable hearing system Codacs™ was designed to close the treatment gap between active middle ear implants and cochlear implants in cases of severe-to-profound mixed hearing loss. The Codacs™ actuator is attached to conventional stapes prosthesis during the implantation and thereby provides acoustical stimulation through a stapedotomy to the cochlea. Cochlear implants (CIs) on the other hand are an established treatment option for profoundly deaf patients including mixed hearing losses that are possible candidates for the Codacs™.In this retrospective study, we compared the clinical outcome of 25 patients with the Codacs™ (≥3 month post-activation) to 54 CI patients (two years post-activation) with comparable pre-operative bone conduction (BC) thresholds that were potential candidates for both categories of devices. The word recognition score (Freiburg monosyllables test) in quiet was significantly (p < 0.05) better in the Codacs™ than in the corresponding CI patients for average pre-operative bone conduction below 60 dB HL and equal in patients with a pre-operative BC PTA between 60 and 70 dB HL. Speech in noise intelligibility (HSM sentences test at +10 dB SNR) was significantly (p < 0.001) better in Codacs™ (80 % median) than in CI patients (25 % median) in all tested groups.Our results indicate for patients with sufficient cochlear reserve that speech intelligibility in noise with the Codacs™ hearing implant is significantly better than with a CI. Further, results in Codacs™ were better predictable, encouraging the extension of the indication to patients with less cochlear reserve than reported here.



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Channeling Your Inner Ear Potassium: K+ Channels in Vestibular Hair Cells

Publication date: Available online 4 February 2016
Source:Hearing Research
Author(s): Frances L. Meredith, Katherine J. Rennie
During development of vestibular hair cells, K⁺ conductances are acquired in a specific pattern. Functionally mature vestibular hair cells express different complements of K⁺ channels which uniquely shape the hair cell receptor potential and filtering properties. In amniote species, type I hair cells (HCI) have a large input conductance due to a ubiquitous low–voltage-activated K⁺ current that activates with slow sigmoidal kinetics at voltages negative to the membrane resting potential. In contrast type II hair cells (HCII) from mammalian and non-mammalian species have voltage-dependent outward K⁺ currents that activate rapidly at or above the resting membrane potential and show significant inactivation. A-type, delayed rectifier and calcium-activated K⁺ channels contribute to the outward K⁺ conductance and are present in varying proportions in HCII. In many species, K⁺ currents in HCII in peripheral locations of vestibular epithelia inactivate more than HCII in more central locations. Two types of inward rectifier currents have been described in both HCI and HCII. A rapidly activating K⁺-selective inward rectifier current (IK1, mediated by Kir2.1 channels) predominates in HCII in peripheral zones, whereas a slower mixed cation inward rectifier current (Ih), shows greater expression in HCII in central zones of vestibular epithelia. The implications for sensory coding of vestibular signals by different types of hair cells are discussed.



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Indication of Direct Acoustical Cochlea Stimulation in Comparison to Cochlear Implants

Publication date: Available online 4 February 2016
Source:Hearing Research
Author(s): Eugen Kludt, Andreas Büchner, Burkard Schwab, Thomas Lenarz, Hannes Maier
The new implantable hearing system Codacs™ was designed to close the treatment gap between active middle ear implants and cochlear implants in cases of severe-to-profound mixed hearing loss. The Codacs™ actuator is attached to conventional stapes prosthesis during the implantation and thereby provides acoustical stimulation through a stapedotomy to the cochlea. Cochlear implants (CIs) on the other hand are an established treatment option for profoundly deaf patients including mixed hearing losses that are possible candidates for the Codacs™.In this retrospective study, we compared the clinical outcome of 25 patients with the Codacs™ (≥3 month post-activation) to 54 CI patients (two years post-activation) with comparable pre-operative bone conduction (BC) thresholds that were potential candidates for both categories of devices. The word recognition score (Freiburg monosyllables test) in quiet was significantly (p < 0.05) better in the Codacs™ than in the corresponding CI patients for average pre-operative bone conduction below 60 dB HL and equal in patients with a pre-operative BC PTA between 60 and 70 dB HL. Speech in noise intelligibility (HSM sentences test at +10 dB SNR) was significantly (p < 0.001) better in Codacs™ (80 % median) than in CI patients (25 % median) in all tested groups.Our results indicate for patients with sufficient cochlear reserve that speech intelligibility in noise with the Codacs™ hearing implant is significantly better than with a CI. Further, results in Codacs™ were better predictable, encouraging the extension of the indication to patients with less cochlear reserve than reported here.



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Channeling Your Inner Ear Potassium: K+ Channels in Vestibular Hair Cells

Publication date: Available online 4 February 2016
Source:Hearing Research
Author(s): Frances L. Meredith, Katherine J. Rennie
During development of vestibular hair cells, K⁺ conductances are acquired in a specific pattern. Functionally mature vestibular hair cells express different complements of K⁺ channels which uniquely shape the hair cell receptor potential and filtering properties. In amniote species, type I hair cells (HCI) have a large input conductance due to a ubiquitous low–voltage-activated K⁺ current that activates with slow sigmoidal kinetics at voltages negative to the membrane resting potential. In contrast type II hair cells (HCII) from mammalian and non-mammalian species have voltage-dependent outward K⁺ currents that activate rapidly at or above the resting membrane potential and show significant inactivation. A-type, delayed rectifier and calcium-activated K⁺ channels contribute to the outward K⁺ conductance and are present in varying proportions in HCII. In many species, K⁺ currents in HCII in peripheral locations of vestibular epithelia inactivate more than HCII in more central locations. Two types of inward rectifier currents have been described in both HCI and HCII. A rapidly activating K⁺-selective inward rectifier current (IK1, mediated by Kir2.1 channels) predominates in HCII in peripheral zones, whereas a slower mixed cation inward rectifier current (Ih), shows greater expression in HCII in central zones of vestibular epithelia. The implications for sensory coding of vestibular signals by different types of hair cells are discussed.



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Indication of Direct Acoustical Cochlea Stimulation in Comparison to Cochlear Implants

Publication date: Available online 4 February 2016
Source:Hearing Research
Author(s): Eugen Kludt, Andreas Büchner, Burkard Schwab, Thomas Lenarz, Hannes Maier
The new implantable hearing system Codacs™ was designed to close the treatment gap between active middle ear implants and cochlear implants in cases of severe-to-profound mixed hearing loss. The Codacs™ actuator is attached to conventional stapes prosthesis during the implantation and thereby provides acoustical stimulation through a stapedotomy to the cochlea. Cochlear implants (CIs) on the other hand are an established treatment option for profoundly deaf patients including mixed hearing losses that are possible candidates for the Codacs™.In this retrospective study, we compared the clinical outcome of 25 patients with the Codacs™ (≥3 month post-activation) to 54 CI patients (two years post-activation) with comparable pre-operative bone conduction (BC) thresholds that were potential candidates for both categories of devices. The word recognition score (Freiburg monosyllables test) in quiet was significantly (p < 0.05) better in the Codacs™ than in the corresponding CI patients for average pre-operative bone conduction below 60 dB HL and equal in patients with a pre-operative BC PTA between 60 and 70 dB HL. Speech in noise intelligibility (HSM sentences test at +10 dB SNR) was significantly (p < 0.001) better in Codacs™ (80 % median) than in CI patients (25 % median) in all tested groups.Our results indicate for patients with sufficient cochlear reserve that speech intelligibility in noise with the Codacs™ hearing implant is significantly better than with a CI. Further, results in Codacs™ were better predictable, encouraging the extension of the indication to patients with less cochlear reserve than reported here.



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Channeling Your Inner Ear Potassium: K+ Channels in Vestibular Hair Cells

Publication date: Available online 4 February 2016
Source:Hearing Research
Author(s): Frances L. Meredith, Katherine J. Rennie
During development of vestibular hair cells, K⁺ conductances are acquired in a specific pattern. Functionally mature vestibular hair cells express different complements of K⁺ channels which uniquely shape the hair cell receptor potential and filtering properties. In amniote species, type I hair cells (HCI) have a large input conductance due to a ubiquitous low–voltage-activated K⁺ current that activates with slow sigmoidal kinetics at voltages negative to the membrane resting potential. In contrast type II hair cells (HCII) from mammalian and non-mammalian species have voltage-dependent outward K⁺ currents that activate rapidly at or above the resting membrane potential and show significant inactivation. A-type, delayed rectifier and calcium-activated K⁺ channels contribute to the outward K⁺ conductance and are present in varying proportions in HCII. In many species, K⁺ currents in HCII in peripheral locations of vestibular epithelia inactivate more than HCII in more central locations. Two types of inward rectifier currents have been described in both HCI and HCII. A rapidly activating K⁺-selective inward rectifier current (IK1, mediated by Kir2.1 channels) predominates in HCII in peripheral zones, whereas a slower mixed cation inward rectifier current (Ih), shows greater expression in HCII in central zones of vestibular epithelia. The implications for sensory coding of vestibular signals by different types of hair cells are discussed.



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Indication of Direct Acoustical Cochlea Stimulation in Comparison to Cochlear Implants

Publication date: Available online 4 February 2016
Source:Hearing Research
Author(s): Eugen Kludt, Andreas Büchner, Burkard Schwab, Thomas Lenarz, Hannes Maier
The new implantable hearing system Codacs™ was designed to close the treatment gap between active middle ear implants and cochlear implants in cases of severe-to-profound mixed hearing loss. The Codacs™ actuator is attached to conventional stapes prosthesis during the implantation and thereby provides acoustical stimulation through a stapedotomy to the cochlea. Cochlear implants (CIs) on the other hand are an established treatment option for profoundly deaf patients including mixed hearing losses that are possible candidates for the Codacs™.In this retrospective study, we compared the clinical outcome of 25 patients with the Codacs™ (≥3 month post-activation) to 54 CI patients (two years post-activation) with comparable pre-operative bone conduction (BC) thresholds that were potential candidates for both categories of devices. The word recognition score (Freiburg monosyllables test) in quiet was significantly (p < 0.05) better in the Codacs™ than in the corresponding CI patients for average pre-operative bone conduction below 60 dB HL and equal in patients with a pre-operative BC PTA between 60 and 70 dB HL. Speech in noise intelligibility (HSM sentences test at +10 dB SNR) was significantly (p < 0.001) better in Codacs™ (80 % median) than in CI patients (25 % median) in all tested groups.Our results indicate for patients with sufficient cochlear reserve that speech intelligibility in noise with the Codacs™ hearing implant is significantly better than with a CI. Further, results in Codacs™ were better predictable, encouraging the extension of the indication to patients with less cochlear reserve than reported here.



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Fast evaluation of transient acoustic fields

The efficient computation of transient fields radiated by non-harmonic source distributions is a problem relevant in numerous areas of acoustics. This paper presents an efficient easily implemented method for the generation of time-dependent spherical harmonic expansions for arbitrary sources, which can be used to compute the transient radiated field at arbitrary points outside the source domain. The method depends on the theory of time-domain spherical harmonic expansions and the solution of Vandermonde systems. Results are presented demonstrating the efficiency and accuracy of the method with respect to full evaluation of the field radiated by a randomized source distribution.

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Multimodal acquisition of articulatory data: Geometrical and temporal registration

Acquisition of dynamic articulatory data is of major importance for studying speech production. It turns out that one technique alone often is not enough to get a correct coverage of the whole vocal tract at a sufficient sampling rate. Ultrasound(US)imaging has been proposed as a good acquisition technique for the tongue surface because it offers a good temporal sampling, does not alter speech production, is cheap, and is widely available. However, it cannot be used alone and this paper describes a multimodal acquisition system which uses electromagnetography sensors to locate the US probe. The paper particularly focuses on the calibration of the US modality which is the key point of the system. This approach enables US data to be merged with other data. The use of the system is illustrated via an experiment consisting of measuring the minimal tongue to palate distance in order to evaluate and design Magnetic Resonance Imaging protocols well suited for the acquisition of three-dimensionalimages of the vocal tract. Compared to manual registration of acquisition modalities which is often used in acquisition of articulatory data, the approach presented relies on automatic techniques well founded from geometrical and mathematical points of view.

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Auditory risk of air rifles.

Auditory risk of air rifles.

Int J Audiol. 2016 Feb;55(sup1):S51-S58

Authors: Lankford JE, Meinke DK, Flamme GA, Finan DS, Stewart M, Tasko S, Murphy WJ

Abstract
OBJECTIVE: To characterize the impulse noise exposure and auditory risk for air rifle users for both youth and adults.
DESIGN: Acoustic characteristics were examined and the auditory risk estimates were evaluated using contemporary damage-risk criteria for unprotected adult listeners and the 120-dB peak limit and LAeq75 exposure limit suggested by the World Health Organization (1999) for children.
STUDY SAMPLE: Impulses were generated by nine pellet air rifles and one BB air rifle.
RESULTS: None of the air rifles generated peak levels that exceeded the 140 dB peak limit for adults, and eight (80%) exceeded the 120 dB peak SPL limit for youth. In general, for both adults and youth, there is minimal auditory risk when shooting fewer than 100 unprotected shots with pellet air rifles. Air rifles with suppressors were less hazardous than those without suppressors, and the pellet air rifles with higher velocities were generally more hazardous than those with lower velocities.
CONCLUSION: To minimize auditory risk, youth should utilize air rifles with an integrated suppressor and lower velocity ratings. Air rifle shooters are advised to wear hearing protection whenever engaging in shooting activities in order to gain self-efficacy and model appropriate hearing health behaviors necessary for recreational firearm use.

PMID: 26840923 [PubMed - as supplied by publisher]

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Speech recognition in noise under hearing protection: A computational study of the combined effects of hearing loss and hearing protector attenuation.

Speech recognition in noise under hearing protection: A computational study of the combined effects of hearing loss and hearing protector attenuation.

Int J Audiol. 2016 Feb;55(sup1):S30-S40

Authors: Giguère C, Berger EH

Abstract
OBJECTIVE: To investigate the effects of hearing protection on speech recognition in noise.
DESIGN: Computational study using a speech recognition model that was previously empirically validated.
STUDY SAMPLE: Recognition scores were calculated in unprotected and protected conditions for four sets of hearing protector attenuation functions in two different noises, for three simulated hearing profiles illustrative of those anticipated in the noisy workplace.
RESULTS: For a normal-hearing profile, recognition scores were not sensitive to the slope of the attenuation function and the overall amount of noise reduction, but protected conditions provided a small but consistent 7-12% benefit compared to unprotected listening. For profiles simulating hearing loss, recognition scores were much more sensitive to the attenuation function. Substantial drops of 30% or more were found compared to unprotected listening in some conditions of steep attenuation slopes and large noise reductions. Attenuation functions modelled from real hearing protectors with nearly-flat attenuation yielded a benefit compared to unprotected listening for all hearing profiles studied. These findings were true in both noises.
CONCLUSIONS: Limiting the slope of the hearing protector attenuation function and/or the overall amount of noise reduction is useful and warranted for workers with hearing loss to prevent adverse effects on speech recognition.

PMID: 26840922 [PubMed - as supplied by publisher]

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Celebrating hearing loss prevention.

Celebrating hearing loss prevention.

Int J Audiol. 2016 Feb;55(sup1):S1-S2

Authors: Le Prell CG, Grantham MA

PMID: 26840921 [PubMed - as supplied by publisher]

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Auditory risk of air rifles.

Auditory risk of air rifles.

Int J Audiol. 2016 Feb;55(sup1):S51-S58

Authors: Lankford JE, Meinke DK, Flamme GA, Finan DS, Stewart M, Tasko S, Murphy WJ

Abstract
OBJECTIVE: To characterize the impulse noise exposure and auditory risk for air rifle users for both youth and adults.
DESIGN: Acoustic characteristics were examined and the auditory risk estimates were evaluated using contemporary damage-risk criteria for unprotected adult listeners and the 120-dB peak limit and LAeq75 exposure limit suggested by the World Health Organization (1999) for children.
STUDY SAMPLE: Impulses were generated by nine pellet air rifles and one BB air rifle.
RESULTS: None of the air rifles generated peak levels that exceeded the 140 dB peak limit for adults, and eight (80%) exceeded the 120 dB peak SPL limit for youth. In general, for both adults and youth, there is minimal auditory risk when shooting fewer than 100 unprotected shots with pellet air rifles. Air rifles with suppressors were less hazardous than those without suppressors, and the pellet air rifles with higher velocities were generally more hazardous than those with lower velocities.
CONCLUSION: To minimize auditory risk, youth should utilize air rifles with an integrated suppressor and lower velocity ratings. Air rifle shooters are advised to wear hearing protection whenever engaging in shooting activities in order to gain self-efficacy and model appropriate hearing health behaviors necessary for recreational firearm use.

PMID: 26840923 [PubMed - as supplied by publisher]

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Speech recognition in noise under hearing protection: A computational study of the combined effects of hearing loss and hearing protector attenuation.

Speech recognition in noise under hearing protection: A computational study of the combined effects of hearing loss and hearing protector attenuation.

Int J Audiol. 2016 Feb;55(sup1):S30-S40

Authors: Giguère C, Berger EH

Abstract
OBJECTIVE: To investigate the effects of hearing protection on speech recognition in noise.
DESIGN: Computational study using a speech recognition model that was previously empirically validated.
STUDY SAMPLE: Recognition scores were calculated in unprotected and protected conditions for four sets of hearing protector attenuation functions in two different noises, for three simulated hearing profiles illustrative of those anticipated in the noisy workplace.
RESULTS: For a normal-hearing profile, recognition scores were not sensitive to the slope of the attenuation function and the overall amount of noise reduction, but protected conditions provided a small but consistent 7-12% benefit compared to unprotected listening. For profiles simulating hearing loss, recognition scores were much more sensitive to the attenuation function. Substantial drops of 30% or more were found compared to unprotected listening in some conditions of steep attenuation slopes and large noise reductions. Attenuation functions modelled from real hearing protectors with nearly-flat attenuation yielded a benefit compared to unprotected listening for all hearing profiles studied. These findings were true in both noises.
CONCLUSIONS: Limiting the slope of the hearing protector attenuation function and/or the overall amount of noise reduction is useful and warranted for workers with hearing loss to prevent adverse effects on speech recognition.

PMID: 26840922 [PubMed - as supplied by publisher]

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Celebrating hearing loss prevention.

Celebrating hearing loss prevention.

Int J Audiol. 2016 Feb;55(sup1):S1-S2

Authors: Le Prell CG, Grantham MA

PMID: 26840921 [PubMed - as supplied by publisher]

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Myo3a Causes Human Dominant Deafness And Interacts With Protocadherin 15-Cd2 Isoform.

Myo3a Causes Human Dominant Deafness And Interacts With Protocadherin 15-Cd2 Isoform.

Hum Mutat. 2016 Feb 3;

Authors: Grati M, Yan D, Raval MH, Walsh T, Ma Q, Chakchouk I, Kannan-Sundhari A, Mittal R, Masmoudi S, Blanton SH, Tekin M, King MC, Yengo CM, Liu XZ

Abstract
Hereditary hearing loss is characterized by both allelic and locus genetic heterogeneity. Both recessive and dominant forms of hearing loss may be caused by different mutations in the same deafness gene. In a family with post-lingual progressive non-syndromic deafness, whole exome sequencing of genomic DNA from five hearing-impaired relatives revealed a single variant, p.Gly488Glu (rs145970949:G>A) in MYO3A, co-segregating with hearing loss as an autosomal dominant trait. This amino acid change, predicted to be pathogenic, alters a highly conserved residue in the motor domain of MYO3A. The mutation severely alters the ATPase activity and motility of the protein in vitro, and the mutant protein fails to accumulate in the filopodia tips in COS7 cells. However, the mutant MYO3A was able to reach the tips of organotypic inner ear culture hair cell stereocilia, raising the possibility of a local effect on positioning of the mechano-electrical transduction (MET) complex at the stereocilia tips. To address this hypothesis, we investigated the interaction of MYO3A with the cytosolic tail of the integral tip-link protein protocadherin 15 (PCDH15), a core component of MET complex. Interestingly, we uncovered a novel interaction between MYO3A and PCDH15 shedding new light on the function of myosin IIIA at stereocilia tips. This article is protected by copyright. All rights reserved.

PMID: 26841241 [PubMed - as supplied by publisher]

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Phenotypic subregions within the split-hand/foot malformation 1 locus.

Phenotypic subregions within the split-hand/foot malformation 1 locus.

Hum Genet. 2016 Feb 2;

Authors: Rasmussen MB, Kreiborg S, Jensen P, Bak M, Mang Y, Lodahl M, Budtz-Jørgensen E, Tommerup N, Tranebjærg L, Rendtorff ND

Abstract
Split-hand/foot malformation 1 (SHFM1) is caused by chromosomal aberrations involving the region 7q21.3, DLX5 mutation, and dysregulation of DLX5/DLX6 expression by long-range position effects. SHFM1 can be isolated or syndromic with incomplete penetrance and a highly variable clinical expression, possibly influenced by sex and imprinting. We report on a new family with five affected individuals with syndromic SHFM1 that includes split-hand/foot malformations, hearing loss, and craniofacial anomalies, and an inv(7)(q21.3q35) present both in the proband and her affected son. The proximal inversion breakpoint, identified by next generation mate-pair sequencing, truncates the SHFM1 locus within the regulatory region of DLX5/6 expression. Through genotype-phenotype correlations of 100 patients with molecularly characterized chromosomal aberrations from 32 SHFM1 families, our findings suggest three phenotypic subregions within the SHFM1 locus associated with (1) isolated SHFM, (2) SHFM and hearing loss, and (3) SHFM, hearing loss, and craniofacial anomalies, respectively (ranked for increasing proximity to DLX5/6), and encompassing previously reported tissue-specific enhancers for DLX5/6. This uniquely well-characterized cohort of SHFM1 patients allowed us to systematically analyze the recently suggested hypothesis of skewed transmission and to confirm a higher penetrance in males vs. females in a subgroup of patients with isolated SHFM.

PMID: 26839112 [PubMed - as supplied by publisher]

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Mutation in TWINKLE in a Large Iranian Family with Progressive External Ophthalmoplegia, Myopathy, Dysphagia and Dysphonia, and Behavior Change.

Mutation in TWINKLE in a Large Iranian Family with Progressive External Ophthalmoplegia, Myopathy, Dysphagia and Dysphonia, and Behavior Change.

Arch Iran Med. 2016 Feb;19(2):87-91

Authors: Tafakhori A, Yu Jin Ng A, Tohari S, Venkatesh B, Lee H, Eskin A, Nelson SF, Bonnard C, Reversade B, Kariminejad A

Abstract
BACKGROUND: TWINKLE (c10orf2) gene is responsible for autosomal dominant progressive external ophthalmoplegia (PEO). In rare cases, additional features such as muscle weakness, peripheral neuropathy, ataxia, cardiomyopathy, dysphagia, dysphonia, cataracts, depression, dementia, parkinsonism, and hearing loss have been reported in association with heterozygous mutations of the TWINKLE gene.
METHODS: We have studied a large Iranian family with myopathy, dysphonia, dysphagia, and behavior change in addition to PEO in affected members.
RESULTS: We identified a missense mutation c.1121G > A in the c10orf2 gene in all affected members. Early death is a novel feature seen in affected members of this family that has not been reported to date.
CONCLUSION: The association of PEO, myopathy, dysphonia, dysphagia, behavior change and early death has not been previously reported in the literature or other patients with this mutation.

PMID: 26838077 [PubMed - in process]

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A new approach of the Star Excursion Balance Test to assess dynamic postural control in people complaining from chronic ankle instability

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Raphaël Pionnier, Nicolas Découfour, Franck Barbier, Christophe Popineau, Emilie Simoneau-Buessinger
The purpose of this study was to quantitatively and qualitatively assess dynamic balance with accuracy in individuals with chronic ankle instability (CAI). To this aim, a motion capture system was used while participants performed the Star Excursion Balance Test (SEBT). Reached distances for the 8 points of the star were automatically computed, thereby excluding any dependence to the experimenter. In addition, new relevant variables were also computed, such as absolute time needed to reach each distance, lower limb ranges of motion during unipodal stance, as well as absolute error of pointing. Velocity of the center of pressure and range of variation of ground reaction forces have also been assessed during the unipodal phase of the SEBT thanks to force plates. CAI group exhibited smaller reached distances and greater absolute error of pointing than the control group (p<0.05). Moreover, the ranges of motion of lower limbs joints, the velocity of the center of pressure and the range of variation of the ground reaction forces were all significantly smaller in the CAI group (p<0.05). These reduced quantitative and qualitative performances highlighted a lower dynamic postural control. The limited body movements and accelerations during the unipodal stance in the CAI group could highlight a protective strategy. The present findings could help clinicians to better understand the motor strategies used by CAI patients during dynamic balance and may guide the rehabilitation process.



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Biomechanical risk factors for tripping during obstacle—Crossing with the trailing limb in patients with type II diabetes mellitus

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Wei-Chun Hsu, Ming-Wei Liu, Tung-Wu Lu
People with type II diabetes mellitus (DM) are at a high risk of falling especially during more challenging locomotor tasks such as obstacle-crossing. The current study aimed to identify the risk factors for tripping in these patients during trailing-limb obstacle-crossing. Fourteen patients with type II DM with or without mild peripheral neuropathy (PN) and 14 healthy controls walked and crossed obstacles of three different heights while their motion data were measured using a motion capture system and two forceplates. The DM group was found to cross obstacles with significantly reduced trailing toe clearance (p<0.05), increasing the probability of the foot hitting the obstacle, and thus the risk of tripping. This altered end-point control was associated with significantly reduced knee flexion and hip adduction of the trailing swing limb (p<0.05), as well as significantly increased ankle plantarflexor moments in the leading stance limb (p<0.05). Therefore, reduced knee flexion and hip adduction of the swing limb are identified as risk factors for tripping during obstacle-crossing. Increased mechanical demands on the ankle plantarflexors suggest that weakness of these muscles may further reduce the already compromised performance of obstacle-crossing in these patients. The current results showed that obstacle-crossing can be used to detect gait deviations and to identify the associated risk of tripping in patients with type II DM without or at an early stage of PN.



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Estimation of foot trajectory during human walking by a wearable inertial measurement unit mounted to the foot

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Naoki Kitagawa, Naomichi Ogihara
To establish a supportive technology for reducing the risk of falling in older people, it is essential to clarify gait characteristics in elderly individuals that are possibly linked to the risk of falling during actual daily activities. In this study, we developed a system to monitor human gait in an outdoor environment using an inertial measurement unit consisting of a tri-axial accelerometer and tri-axial gyroscope. Step-by-step foot trajectories were estimated from the sensor unit attached to the dorsum of the foot. Specifically, stride length and foot clearance were calculated by integrating the gravity-compensated translational acceleration over time during the swing phase. Zero vertical velocity and displacement corrections were applied to obtain the final trajectory, assuming the slope of the walking surface is negligible. Short, normal, and long stride-length walking of 10 healthy participants was simultaneously measured using the proposed system and a conventional motion capture system to evaluate the accuracy of the estimated foot trajectory. Mean accuracy and precision were approximately 20±50mm, for stride length, and 2±7mm for foot clearance, indicating that the swing phase trajectory of the sensor unit attached to the foot was reconstructed more accurately and precisely using the proposed system than with previously published methods owing to the flat floor assumption. Although some methodological limitations certainly apply, this system will serve as a useful tool to monitor human walking during daily activities.



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Knee contact forces are not altered in early knee osteoarthritis

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): S. Meireles, F. De Groote, N.D. Reeves, S. Verschueren, C. Maganaris, F. Luyten, I. Jonkers
ObjectiveThis study calculated knee contact forces (KCF) and its relations with knee external knee adduction moments (KAM) and/or flexion moments (KFM) during the stance phase of gait in patients with early osteoarthritis (OA), classified based on early joint degeneration on Magnetic Resonance Imaging (MRI). We aimed at assessing if altered KCF are already present in early structural degeneration.DesignThree-dimensional motion and ground reaction force data in 59 subjects with medial compartment knee OA (N=23 established OA, N=16 early OA, N=20 controls) were used as input for a musculoskeletal model. KAM and KFM, and KCF were estimated using OpenSim software.ResultsNo significant differences were found between controls and subjects with early OA. In early OA patients, KAM significantly explained 69% of the variance associated with the first peaks KCF but only KFM contributed to the second peaks KCF. The multiple correlation, combining KAM and KFM, showed to be higher. However, only 20% of the variance of second peak KCF was explained by both moments in established OA.ConclusionKCF are not increased in patients with early OA, suggesting that knee joint overload is more a consequence of further joint degeneration in more advanced stages of OA. Additionally, our results clearly show that KAM is not sufficient to predict joint loading at the end of the stance, where KFM contributes substantially to the loading, especially in early OA.



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Analytical evaluation of the effects of inconsistent anthropometric measurements on joint kinematics in motion capturing

Publication date: Available online 3 February 2016
Source:Gait & Posture
Author(s): Dominik Krumm, John Cockcroft, Falk Zaumseil, Stephan Odenwald, Thomas L. Milani, Quinette Louw
Clinical decisions based on gait data obtained by optoelectronic motion capturing require profound knowledge about the repeatability of the used measurement systems and methods. The purpose of this study was to evaluate the effects of inconsistent anthropometric measurements on joint kinematics calculated with the Plug-in Gait model. Therefore, a sensitivity study was conducted to ascertain how joint kinematics output is affected to different anthropometric data input. One previously examined gait session of a healthy male subject and his anthropometric data that were assessed by two experienced examiners served as a basis for this analytical evaluation. This sensitivity study yielded a maximum difference in joint kinematics by the two sets of anthropometrics of up to 1.2°. In conclusion, this study has shown that the reliability of subjects’ anthropometrics assessed by experienced examiners has no considerable effects on joint kinematics.



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A new approach of the Star Excursion Balance Test to assess dynamic postural control in people complaining from chronic ankle instability

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Raphaël Pionnier, Nicolas Découfour, Franck Barbier, Christophe Popineau, Emilie Simoneau-Buessinger
The purpose of this study was to quantitatively and qualitatively assess dynamic balance with accuracy in individuals with chronic ankle instability (CAI). To this aim, a motion capture system was used while participants performed the Star Excursion Balance Test (SEBT). Reached distances for the 8 points of the star were automatically computed, thereby excluding any dependence to the experimenter. In addition, new relevant variables were also computed, such as absolute time needed to reach each distance, lower limb ranges of motion during unipodal stance, as well as absolute error of pointing. Velocity of the center of pressure and range of variation of ground reaction forces have also been assessed during the unipodal phase of the SEBT thanks to force plates. CAI group exhibited smaller reached distances and greater absolute error of pointing than the control group (p<0.05). Moreover, the ranges of motion of lower limbs joints, the velocity of the center of pressure and the range of variation of the ground reaction forces were all significantly smaller in the CAI group (p<0.05). These reduced quantitative and qualitative performances highlighted a lower dynamic postural control. The limited body movements and accelerations during the unipodal stance in the CAI group could highlight a protective strategy. The present findings could help clinicians to better understand the motor strategies used by CAI patients during dynamic balance and may guide the rehabilitation process.



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Biomechanical risk factors for tripping during obstacle—Crossing with the trailing limb in patients with type II diabetes mellitus

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Wei-Chun Hsu, Ming-Wei Liu, Tung-Wu Lu
People with type II diabetes mellitus (DM) are at a high risk of falling especially during more challenging locomotor tasks such as obstacle-crossing. The current study aimed to identify the risk factors for tripping in these patients during trailing-limb obstacle-crossing. Fourteen patients with type II DM with or without mild peripheral neuropathy (PN) and 14 healthy controls walked and crossed obstacles of three different heights while their motion data were measured using a motion capture system and two forceplates. The DM group was found to cross obstacles with significantly reduced trailing toe clearance (p<0.05), increasing the probability of the foot hitting the obstacle, and thus the risk of tripping. This altered end-point control was associated with significantly reduced knee flexion and hip adduction of the trailing swing limb (p<0.05), as well as significantly increased ankle plantarflexor moments in the leading stance limb (p<0.05). Therefore, reduced knee flexion and hip adduction of the swing limb are identified as risk factors for tripping during obstacle-crossing. Increased mechanical demands on the ankle plantarflexors suggest that weakness of these muscles may further reduce the already compromised performance of obstacle-crossing in these patients. The current results showed that obstacle-crossing can be used to detect gait deviations and to identify the associated risk of tripping in patients with type II DM without or at an early stage of PN.



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Estimation of foot trajectory during human walking by a wearable inertial measurement unit mounted to the foot

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Naoki Kitagawa, Naomichi Ogihara
To establish a supportive technology for reducing the risk of falling in older people, it is essential to clarify gait characteristics in elderly individuals that are possibly linked to the risk of falling during actual daily activities. In this study, we developed a system to monitor human gait in an outdoor environment using an inertial measurement unit consisting of a tri-axial accelerometer and tri-axial gyroscope. Step-by-step foot trajectories were estimated from the sensor unit attached to the dorsum of the foot. Specifically, stride length and foot clearance were calculated by integrating the gravity-compensated translational acceleration over time during the swing phase. Zero vertical velocity and displacement corrections were applied to obtain the final trajectory, assuming the slope of the walking surface is negligible. Short, normal, and long stride-length walking of 10 healthy participants was simultaneously measured using the proposed system and a conventional motion capture system to evaluate the accuracy of the estimated foot trajectory. Mean accuracy and precision were approximately 20±50mm, for stride length, and 2±7mm for foot clearance, indicating that the swing phase trajectory of the sensor unit attached to the foot was reconstructed more accurately and precisely using the proposed system than with previously published methods owing to the flat floor assumption. Although some methodological limitations certainly apply, this system will serve as a useful tool to monitor human walking during daily activities.



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Knee contact forces are not altered in early knee osteoarthritis

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): S. Meireles, F. De Groote, N.D. Reeves, S. Verschueren, C. Maganaris, F. Luyten, I. Jonkers
ObjectiveThis study calculated knee contact forces (KCF) and its relations with knee external knee adduction moments (KAM) and/or flexion moments (KFM) during the stance phase of gait in patients with early osteoarthritis (OA), classified based on early joint degeneration on Magnetic Resonance Imaging (MRI). We aimed at assessing if altered KCF are already present in early structural degeneration.DesignThree-dimensional motion and ground reaction force data in 59 subjects with medial compartment knee OA (N=23 established OA, N=16 early OA, N=20 controls) were used as input for a musculoskeletal model. KAM and KFM, and KCF were estimated using OpenSim software.ResultsNo significant differences were found between controls and subjects with early OA. In early OA patients, KAM significantly explained 69% of the variance associated with the first peaks KCF but only KFM contributed to the second peaks KCF. The multiple correlation, combining KAM and KFM, showed to be higher. However, only 20% of the variance of second peak KCF was explained by both moments in established OA.ConclusionKCF are not increased in patients with early OA, suggesting that knee joint overload is more a consequence of further joint degeneration in more advanced stages of OA. Additionally, our results clearly show that KAM is not sufficient to predict joint loading at the end of the stance, where KFM contributes substantially to the loading, especially in early OA.



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Analytical evaluation of the effects of inconsistent anthropometric measurements on joint kinematics in motion capturing

Publication date: Available online 3 February 2016
Source:Gait & Posture
Author(s): Dominik Krumm, John Cockcroft, Falk Zaumseil, Stephan Odenwald, Thomas L. Milani, Quinette Louw
Clinical decisions based on gait data obtained by optoelectronic motion capturing require profound knowledge about the repeatability of the used measurement systems and methods. The purpose of this study was to evaluate the effects of inconsistent anthropometric measurements on joint kinematics calculated with the Plug-in Gait model. Therefore, a sensitivity study was conducted to ascertain how joint kinematics output is affected to different anthropometric data input. One previously examined gait session of a healthy male subject and his anthropometric data that were assessed by two experienced examiners served as a basis for this analytical evaluation. This sensitivity study yielded a maximum difference in joint kinematics by the two sets of anthropometrics of up to 1.2°. In conclusion, this study has shown that the reliability of subjects’ anthropometrics assessed by experienced examiners has no considerable effects on joint kinematics.



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A new approach of the Star Excursion Balance Test to assess dynamic postural control in people complaining from chronic ankle instability

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Raphaël Pionnier, Nicolas Découfour, Franck Barbier, Christophe Popineau, Emilie Simoneau-Buessinger
The purpose of this study was to quantitatively and qualitatively assess dynamic balance with accuracy in individuals with chronic ankle instability (CAI). To this aim, a motion capture system was used while participants performed the Star Excursion Balance Test (SEBT). Reached distances for the 8 points of the star were automatically computed, thereby excluding any dependence to the experimenter. In addition, new relevant variables were also computed, such as absolute time needed to reach each distance, lower limb ranges of motion during unipodal stance, as well as absolute error of pointing. Velocity of the center of pressure and range of variation of ground reaction forces have also been assessed during the unipodal phase of the SEBT thanks to force plates. CAI group exhibited smaller reached distances and greater absolute error of pointing than the control group (p<0.05). Moreover, the ranges of motion of lower limbs joints, the velocity of the center of pressure and the range of variation of the ground reaction forces were all significantly smaller in the CAI group (p<0.05). These reduced quantitative and qualitative performances highlighted a lower dynamic postural control. The limited body movements and accelerations during the unipodal stance in the CAI group could highlight a protective strategy. The present findings could help clinicians to better understand the motor strategies used by CAI patients during dynamic balance and may guide the rehabilitation process.



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Biomechanical risk factors for tripping during obstacle—Crossing with the trailing limb in patients with type II diabetes mellitus

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Wei-Chun Hsu, Ming-Wei Liu, Tung-Wu Lu
People with type II diabetes mellitus (DM) are at a high risk of falling especially during more challenging locomotor tasks such as obstacle-crossing. The current study aimed to identify the risk factors for tripping in these patients during trailing-limb obstacle-crossing. Fourteen patients with type II DM with or without mild peripheral neuropathy (PN) and 14 healthy controls walked and crossed obstacles of three different heights while their motion data were measured using a motion capture system and two forceplates. The DM group was found to cross obstacles with significantly reduced trailing toe clearance (p<0.05), increasing the probability of the foot hitting the obstacle, and thus the risk of tripping. This altered end-point control was associated with significantly reduced knee flexion and hip adduction of the trailing swing limb (p<0.05), as well as significantly increased ankle plantarflexor moments in the leading stance limb (p<0.05). Therefore, reduced knee flexion and hip adduction of the swing limb are identified as risk factors for tripping during obstacle-crossing. Increased mechanical demands on the ankle plantarflexors suggest that weakness of these muscles may further reduce the already compromised performance of obstacle-crossing in these patients. The current results showed that obstacle-crossing can be used to detect gait deviations and to identify the associated risk of tripping in patients with type II DM without or at an early stage of PN.



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Estimation of foot trajectory during human walking by a wearable inertial measurement unit mounted to the foot

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): Naoki Kitagawa, Naomichi Ogihara
To establish a supportive technology for reducing the risk of falling in older people, it is essential to clarify gait characteristics in elderly individuals that are possibly linked to the risk of falling during actual daily activities. In this study, we developed a system to monitor human gait in an outdoor environment using an inertial measurement unit consisting of a tri-axial accelerometer and tri-axial gyroscope. Step-by-step foot trajectories were estimated from the sensor unit attached to the dorsum of the foot. Specifically, stride length and foot clearance were calculated by integrating the gravity-compensated translational acceleration over time during the swing phase. Zero vertical velocity and displacement corrections were applied to obtain the final trajectory, assuming the slope of the walking surface is negligible. Short, normal, and long stride-length walking of 10 healthy participants was simultaneously measured using the proposed system and a conventional motion capture system to evaluate the accuracy of the estimated foot trajectory. Mean accuracy and precision were approximately 20±50mm, for stride length, and 2±7mm for foot clearance, indicating that the swing phase trajectory of the sensor unit attached to the foot was reconstructed more accurately and precisely using the proposed system than with previously published methods owing to the flat floor assumption. Although some methodological limitations certainly apply, this system will serve as a useful tool to monitor human walking during daily activities.



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Knee contact forces are not altered in early knee osteoarthritis

Publication date: March 2016
Source:Gait & Posture, Volume 45
Author(s): S. Meireles, F. De Groote, N.D. Reeves, S. Verschueren, C. Maganaris, F. Luyten, I. Jonkers
ObjectiveThis study calculated knee contact forces (KCF) and its relations with knee external knee adduction moments (KAM) and/or flexion moments (KFM) during the stance phase of gait in patients with early osteoarthritis (OA), classified based on early joint degeneration on Magnetic Resonance Imaging (MRI). We aimed at assessing if altered KCF are already present in early structural degeneration.DesignThree-dimensional motion and ground reaction force data in 59 subjects with medial compartment knee OA (N=23 established OA, N=16 early OA, N=20 controls) were used as input for a musculoskeletal model. KAM and KFM, and KCF were estimated using OpenSim software.ResultsNo significant differences were found between controls and subjects with early OA. In early OA patients, KAM significantly explained 69% of the variance associated with the first peaks KCF but only KFM contributed to the second peaks KCF. The multiple correlation, combining KAM and KFM, showed to be higher. However, only 20% of the variance of second peak KCF was explained by both moments in established OA.ConclusionKCF are not increased in patients with early OA, suggesting that knee joint overload is more a consequence of further joint degeneration in more advanced stages of OA. Additionally, our results clearly show that KAM is not sufficient to predict joint loading at the end of the stance, where KFM contributes substantially to the loading, especially in early OA.



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Analytical evaluation of the effects of inconsistent anthropometric measurements on joint kinematics in motion capturing

Publication date: Available online 3 February 2016
Source:Gait & Posture
Author(s): Dominik Krumm, John Cockcroft, Falk Zaumseil, Stephan Odenwald, Thomas L. Milani, Quinette Louw
Clinical decisions based on gait data obtained by optoelectronic motion capturing require profound knowledge about the repeatability of the used measurement systems and methods. The purpose of this study was to evaluate the effects of inconsistent anthropometric measurements on joint kinematics calculated with the Plug-in Gait model. Therefore, a sensitivity study was conducted to ascertain how joint kinematics output is affected to different anthropometric data input. One previously examined gait session of a healthy male subject and his anthropometric data that were assessed by two experienced examiners served as a basis for this analytical evaluation. This sensitivity study yielded a maximum difference in joint kinematics by the two sets of anthropometrics of up to 1.2°. In conclusion, this study has shown that the reliability of subjects’ anthropometrics assessed by experienced examiners has no considerable effects on joint kinematics.



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Auditory risk of air rifles.

Auditory risk of air rifles.

Int J Audiol. 2016 Feb;55(sup1):S51-S58

Authors: Lankford JE, Meinke DK, Flamme GA, Finan DS, Stewart M, Tasko S, Murphy WJ

Abstract
OBJECTIVE: To characterize the impulse noise exposure and auditory risk for air rifle users for both youth and adults.
DESIGN: Acoustic characteristics were examined and the auditory risk estimates were evaluated using contemporary damage-risk criteria for unprotected adult listeners and the 120-dB peak limit and LAeq75 exposure limit suggested by the World Health Organization (1999) for children.
STUDY SAMPLE: Impulses were generated by nine pellet air rifles and one BB air rifle.
RESULTS: None of the air rifles generated peak levels that exceeded the 140 dB peak limit for adults, and eight (80%) exceeded the 120 dB peak SPL limit for youth. In general, for both adults and youth, there is minimal auditory risk when shooting fewer than 100 unprotected shots with pellet air rifles. Air rifles with suppressors were less hazardous than those without suppressors, and the pellet air rifles with higher velocities were generally more hazardous than those with lower velocities.
CONCLUSION: To minimize auditory risk, youth should utilize air rifles with an integrated suppressor and lower velocity ratings. Air rifle shooters are advised to wear hearing protection whenever engaging in shooting activities in order to gain self-efficacy and model appropriate hearing health behaviors necessary for recreational firearm use.

PMID: 26840923 [PubMed - as supplied by publisher]

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Speech recognition in noise under hearing protection: A computational study of the combined effects of hearing loss and hearing protector attenuation.

Speech recognition in noise under hearing protection: A computational study of the combined effects of hearing loss and hearing protector attenuation.

Int J Audiol. 2016 Feb;55(sup1):S30-S40

Authors: Giguère C, Berger EH

Abstract
OBJECTIVE: To investigate the effects of hearing protection on speech recognition in noise.
DESIGN: Computational study using a speech recognition model that was previously empirically validated.
STUDY SAMPLE: Recognition scores were calculated in unprotected and protected conditions for four sets of hearing protector attenuation functions in two different noises, for three simulated hearing profiles illustrative of those anticipated in the noisy workplace.
RESULTS: For a normal-hearing profile, recognition scores were not sensitive to the slope of the attenuation function and the overall amount of noise reduction, but protected conditions provided a small but consistent 7-12% benefit compared to unprotected listening. For profiles simulating hearing loss, recognition scores were much more sensitive to the attenuation function. Substantial drops of 30% or more were found compared to unprotected listening in some conditions of steep attenuation slopes and large noise reductions. Attenuation functions modelled from real hearing protectors with nearly-flat attenuation yielded a benefit compared to unprotected listening for all hearing profiles studied. These findings were true in both noises.
CONCLUSIONS: Limiting the slope of the hearing protector attenuation function and/or the overall amount of noise reduction is useful and warranted for workers with hearing loss to prevent adverse effects on speech recognition.

PMID: 26840922 [PubMed - as supplied by publisher]

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Celebrating hearing loss prevention.

Celebrating hearing loss prevention.

Int J Audiol. 2016 Feb;55(sup1):S1-S2

Authors: Le Prell CG, Grantham MA

PMID: 26840921 [PubMed - as supplied by publisher]

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Auditory risk of air rifles.

Auditory risk of air rifles.

Int J Audiol. 2016 Feb;55(sup1):S51-S58

Authors: Lankford JE, Meinke DK, Flamme GA, Finan DS, Stewart M, Tasko S, Murphy WJ

Abstract
OBJECTIVE: To characterize the impulse noise exposure and auditory risk for air rifle users for both youth and adults.
DESIGN: Acoustic characteristics were examined and the auditory risk estimates were evaluated using contemporary damage-risk criteria for unprotected adult listeners and the 120-dB peak limit and LAeq75 exposure limit suggested by the World Health Organization (1999) for children.
STUDY SAMPLE: Impulses were generated by nine pellet air rifles and one BB air rifle.
RESULTS: None of the air rifles generated peak levels that exceeded the 140 dB peak limit for adults, and eight (80%) exceeded the 120 dB peak SPL limit for youth. In general, for both adults and youth, there is minimal auditory risk when shooting fewer than 100 unprotected shots with pellet air rifles. Air rifles with suppressors were less hazardous than those without suppressors, and the pellet air rifles with higher velocities were generally more hazardous than those with lower velocities.
CONCLUSION: To minimize auditory risk, youth should utilize air rifles with an integrated suppressor and lower velocity ratings. Air rifle shooters are advised to wear hearing protection whenever engaging in shooting activities in order to gain self-efficacy and model appropriate hearing health behaviors necessary for recreational firearm use.

PMID: 26840923 [PubMed - as supplied by publisher]

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Speech recognition in noise under hearing protection: A computational study of the combined effects of hearing loss and hearing protector attenuation.

Speech recognition in noise under hearing protection: A computational study of the combined effects of hearing loss and hearing protector attenuation.

Int J Audiol. 2016 Feb;55(sup1):S30-S40

Authors: Giguère C, Berger EH

Abstract
OBJECTIVE: To investigate the effects of hearing protection on speech recognition in noise.
DESIGN: Computational study using a speech recognition model that was previously empirically validated.
STUDY SAMPLE: Recognition scores were calculated in unprotected and protected conditions for four sets of hearing protector attenuation functions in two different noises, for three simulated hearing profiles illustrative of those anticipated in the noisy workplace.
RESULTS: For a normal-hearing profile, recognition scores were not sensitive to the slope of the attenuation function and the overall amount of noise reduction, but protected conditions provided a small but consistent 7-12% benefit compared to unprotected listening. For profiles simulating hearing loss, recognition scores were much more sensitive to the attenuation function. Substantial drops of 30% or more were found compared to unprotected listening in some conditions of steep attenuation slopes and large noise reductions. Attenuation functions modelled from real hearing protectors with nearly-flat attenuation yielded a benefit compared to unprotected listening for all hearing profiles studied. These findings were true in both noises.
CONCLUSIONS: Limiting the slope of the hearing protector attenuation function and/or the overall amount of noise reduction is useful and warranted for workers with hearing loss to prevent adverse effects on speech recognition.

PMID: 26840922 [PubMed - as supplied by publisher]

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Celebrating hearing loss prevention.

Celebrating hearing loss prevention.

Int J Audiol. 2016 Feb;55(sup1):S1-S2

Authors: Le Prell CG, Grantham MA

PMID: 26840921 [PubMed - as supplied by publisher]

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