A Cure for Hearing Loss on the Horizon

​Activation of the signaling pathway that regulates the differentiation of hair cells could represent a new approach to cochlear regeneration and potentially restore hearing, a new study found (Eur J Neurosci. 2018 Sep 30. doi: 10.1111/ejn.14183. [Epub ahead of print]). Researchers from the University of Rochester Medical Center and the Massachusetts Ear and Eye Infirmary hypothesized that signaling from the epidermal growth factor receptor family may play a role in cochlear regeneration. Specifically, they focused on a receptor called ERBB2, which is found in cochlear support cells. They found that activating the ERBB2 pathway triggered a cascading series of cellular events by which cochlear support cells began to proliferate and start the process of activating other neighboring stem cells to become new sensory hair cells. This process not only could impact the regeneration of sensory hair cells but also support their integration with nerve cells. The authors said their findings suggest a new model where an interplay of cell signaling regulates regeneration by endogenous stem-like cells. 

Published: 10/19/2018 11:00:00 AM

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A Cure for Hearing Loss on the Horizon

​Activation of the signaling pathway that regulates the differentiation of hair cells could represent a new approach to cochlear regeneration and potentially restore hearing, a new study found (Eur J Neurosci. 2018 Sep 30. doi: 10.1111/ejn.14183. [Epub ahead of print]). Researchers from the University of Rochester Medical Center and the Massachusetts Ear and Eye Infirmary hypothesized that signaling from the epidermal growth factor receptor family may play a role in cochlear regeneration. Specifically, they focused on a receptor called ERBB2, which is found in cochlear support cells. They found that activating the ERBB2 pathway triggered a cascading series of cellular events by which cochlear support cells began to proliferate and start the process of activating other neighboring stem cells to become new sensory hair cells. This process not only could impact the regeneration of sensory hair cells but also support their integration with nerve cells. The authors said their findings suggest a new model where an interplay of cell signaling regulates regeneration by endogenous stem-like cells. 

Published: 10/19/2018 11:00:00 AM

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Objective Binaural Loudness Balancing Based on 40-Hz Auditory Steady-State Responses. Part II: Asymmetric and Bimodal Hearing.

Related Articles

Objective Binaural Loudness Balancing Based on 40-Hz Auditory Steady-State Responses. Part II: Asymmetric and Bimodal Hearing.

Trends Hear. 2018 Jan-Dec;22:2331216518805363

Authors: Van Eeckhoutte M, Spirrov D, Wouters J, Francart T

Abstract
In Part I, we investigated 40-Hz auditory steady-state response (ASSR) amplitudes for the use of objective loudness balancing across the ears for normal-hearing participants and found median across-ear ratios in ASSR amplitudes close to 1. In this part, we further investigated whether the ASSR can be used to estimate binaural loudness balance for listeners with asymmetric hearing, for whom binaural loudness balancing is of particular interest. We tested participants with asymmetric hearing and participants with bimodal hearing, who hear with electrical stimulation through a cochlear implant (CI) in one ear and with acoustical stimulation in the other ear. Behavioral loudness balancing was performed at different percentages of the dynamic range. Acoustical carrier frequencies were 500, 1000, or 2000 Hz, and CI channels were stimulated in apical or middle regions in the cochlea. For both groups, the ASSR amplitudes at balanced loudness levels were similar for the two ears, with median ratios between left and right ear stimulation close to 1. However, individual variability was observed. For participants with asymmetric hearing loss, the difference between the behavioral balanced levels and the ASSR-predicted balanced levels was smaller than 10 dB in 50% and 56% of cases, for 500 Hz and 2000 Hz, respectively. For bimodal listeners, these percentages were 89% and 60%. Apical CI channels yielded significantly better results (median difference near 0 dB) than middle CI channels, which had a median difference of -7.25 dB.

PMID: 30334496 [PubMed - in process]

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Objective Binaural Loudness Balancing Based on 40-Hz Auditory Steady-State Responses. Part I: Normal Hearing.

Related Articles

Objective Binaural Loudness Balancing Based on 40-Hz Auditory Steady-State Responses. Part I: Normal Hearing.

Trends Hear. 2018 Jan-Dec;22:2331216518805352

Authors: Van Eeckhoutte M, Wouters J, Francart T

Abstract
Psychophysical procedures are used to balance loudness across the ears. However, they can be difficult and require active cooperation. We investigated whether 40-Hz auditory steady-state response (ASSR) amplitudes can be used to objectively estimate the balanced loudness across the ears for a group of young, normal-hearing participants. The 40-Hz ASSRs were recorded using monaural stimuli with carrier frequencies of 500, 1000, or 2000 Hz over a range of levels between 40 and 80 dB SPL. Behavioral loudness balancing was performed for at least one reference level of the left ear. ASSR amplitude growth functions were listener dependent, but median across-ear ratios in ASSR amplitudes were close to 1. The differences between the ASSR-predicted balanced levels and the behaviorally found balanced levels were smaller than 5 dB in 59% of cases and smaller than 10 dB in 85% of cases. The differences between the ASSR-predicted balanced levels and the reference levels were smaller than 5 dB in 54% of cases and smaller than 10 dB in 87% of cases. No clear hemispheric lateralization was found for 40-Hz ASSRs, with the exception of responses evoked by stimulus levels of 40 to 60 dB SPL at 2000 Hz.

PMID: 30334493 [PubMed - in process]

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Objective Binaural Loudness Balancing Based on 40-Hz Auditory Steady-State Responses. Part II: Asymmetric and Bimodal Hearing.

Related Articles

Objective Binaural Loudness Balancing Based on 40-Hz Auditory Steady-State Responses. Part II: Asymmetric and Bimodal Hearing.

Trends Hear. 2018 Jan-Dec;22:2331216518805363

Authors: Van Eeckhoutte M, Spirrov D, Wouters J, Francart T

Abstract
In Part I, we investigated 40-Hz auditory steady-state response (ASSR) amplitudes for the use of objective loudness balancing across the ears for normal-hearing participants and found median across-ear ratios in ASSR amplitudes close to 1. In this part, we further investigated whether the ASSR can be used to estimate binaural loudness balance for listeners with asymmetric hearing, for whom binaural loudness balancing is of particular interest. We tested participants with asymmetric hearing and participants with bimodal hearing, who hear with electrical stimulation through a cochlear implant (CI) in one ear and with acoustical stimulation in the other ear. Behavioral loudness balancing was performed at different percentages of the dynamic range. Acoustical carrier frequencies were 500, 1000, or 2000 Hz, and CI channels were stimulated in apical or middle regions in the cochlea. For both groups, the ASSR amplitudes at balanced loudness levels were similar for the two ears, with median ratios between left and right ear stimulation close to 1. However, individual variability was observed. For participants with asymmetric hearing loss, the difference between the behavioral balanced levels and the ASSR-predicted balanced levels was smaller than 10 dB in 50% and 56% of cases, for 500 Hz and 2000 Hz, respectively. For bimodal listeners, these percentages were 89% and 60%. Apical CI channels yielded significantly better results (median difference near 0 dB) than middle CI channels, which had a median difference of -7.25 dB.

PMID: 30334496 [PubMed - in process]

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via IFTTT

Objective Binaural Loudness Balancing Based on 40-Hz Auditory Steady-State Responses. Part I: Normal Hearing.

Related Articles

Objective Binaural Loudness Balancing Based on 40-Hz Auditory Steady-State Responses. Part I: Normal Hearing.

Trends Hear. 2018 Jan-Dec;22:2331216518805352

Authors: Van Eeckhoutte M, Wouters J, Francart T

Abstract
Psychophysical procedures are used to balance loudness across the ears. However, they can be difficult and require active cooperation. We investigated whether 40-Hz auditory steady-state response (ASSR) amplitudes can be used to objectively estimate the balanced loudness across the ears for a group of young, normal-hearing participants. The 40-Hz ASSRs were recorded using monaural stimuli with carrier frequencies of 500, 1000, or 2000 Hz over a range of levels between 40 and 80 dB SPL. Behavioral loudness balancing was performed for at least one reference level of the left ear. ASSR amplitude growth functions were listener dependent, but median across-ear ratios in ASSR amplitudes were close to 1. The differences between the ASSR-predicted balanced levels and the behaviorally found balanced levels were smaller than 5 dB in 59% of cases and smaller than 10 dB in 85% of cases. The differences between the ASSR-predicted balanced levels and the reference levels were smaller than 5 dB in 54% of cases and smaller than 10 dB in 87% of cases. No clear hemispheric lateralization was found for 40-Hz ASSRs, with the exception of responses evoked by stimulus levels of 40 to 60 dB SPL at 2000 Hz.

PMID: 30334493 [PubMed - in process]

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High frequency transient-evoked otoacoustic emission measurements using chirp and click stimuli

Publication date: Available online 18 October 2018

Source: Hearing Research

Author(s): Douglas H. Keefe, M. Patrick Feeney, Lisa L. Hunter, Denis F. Fitzpatrick, Chelsea M. Blankenship, Angela C. Garinis, Daniel B. Putterman, Marcin Wróblewski

Abstract

Transient-evoked otoacoustic emissions (TEOAEs) at high frequencies are a non-invasive physiological test of basilar membrane mechanics at the basal end, and have clinical potential to detect risk of hearing loss related to outer-hair-cell dysfunction. Using stimuli with constant incident pressure across frequency, TEOAEs were measured in experiment 1 at low frequencies (0.7-8 kHz) and high frequencies (7.1-14.7 kHz) in adults with normal hearing up to 8 kHz and varying hearing levels from 9 to 16 kHz. In combination with click stimuli, chirp stimuli were used with slow, medium and fast sweep rates for which the local frequency increased or decreased with time. Chirp TEOAEs were transformed into equivalent click TEOAEs by inverse filtering out chirp stimulus phase, and analyzed similarly to click TEOAEs. To improve detection above 8 kHz, TEOAEs were measured in experiment 2 with higher-level stimuli and longer averaging times. These changes increased the TEOAE signal-to-noise ratio (SNR) by 10 dB. Slower sweep rates were investigated but the elicited TEOAEs were detected in fewer ears compared to faster rates. Data were acquired in adults and children (age 11-17 y.), including children with cystic fibrosis (CF) treated with ototoxic antibiotics. Test-retest measurements revealed satisfactory repeatability of high-frequency TEOAE SNR (median of 1.3 dB) and coherence synchrony measure, despite small test-retest differences related to changes in forward and reverse transmission in the ear canal. The results suggest the potential use of such tests to screen for sensorineural hearing loss, including ototoxic loss. Experiment 2 was a feasibility study to explore TEOAE test parameters that might be used in a full-scale study to screen CF patients for risk of ototoxic hearing loss.

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High frequency transient-evoked otoacoustic emission measurements using chirp and click stimuli

Publication date: Available online 18 October 2018

Source: Hearing Research

Author(s): Douglas H. Keefe, M. Patrick Feeney, Lisa L. Hunter, Denis F. Fitzpatrick, Chelsea M. Blankenship, Angela C. Garinis, Daniel B. Putterman, Marcin Wróblewski

Abstract

Transient-evoked otoacoustic emissions (TEOAEs) at high frequencies are a non-invasive physiological test of basilar membrane mechanics at the basal end, and have clinical potential to detect risk of hearing loss related to outer-hair-cell dysfunction. Using stimuli with constant incident pressure across frequency, TEOAEs were measured in experiment 1 at low frequencies (0.7-8 kHz) and high frequencies (7.1-14.7 kHz) in adults with normal hearing up to 8 kHz and varying hearing levels from 9 to 16 kHz. In combination with click stimuli, chirp stimuli were used with slow, medium and fast sweep rates for which the local frequency increased or decreased with time. Chirp TEOAEs were transformed into equivalent click TEOAEs by inverse filtering out chirp stimulus phase, and analyzed similarly to click TEOAEs. To improve detection above 8 kHz, TEOAEs were measured in experiment 2 with higher-level stimuli and longer averaging times. These changes increased the TEOAE signal-to-noise ratio (SNR) by 10 dB. Slower sweep rates were investigated but the elicited TEOAEs were detected in fewer ears compared to faster rates. Data were acquired in adults and children (age 11-17 y.), including children with cystic fibrosis (CF) treated with ototoxic antibiotics. Test-retest measurements revealed satisfactory repeatability of high-frequency TEOAE SNR (median of 1.3 dB) and coherence synchrony measure, despite small test-retest differences related to changes in forward and reverse transmission in the ear canal. The results suggest the potential use of such tests to screen for sensorineural hearing loss, including ototoxic loss. Experiment 2 was a feasibility study to explore TEOAE test parameters that might be used in a full-scale study to screen CF patients for risk of ototoxic hearing loss.

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High frequency transient-evoked otoacoustic emission measurements using chirp and click stimuli

Publication date: Available online 18 October 2018

Source: Hearing Research

Author(s): Douglas H. Keefe, M. Patrick Feeney, Lisa L. Hunter, Denis F. Fitzpatrick, Chelsea M. Blankenship, Angela C. Garinis, Daniel B. Putterman, Marcin Wróblewski

Abstract

Transient-evoked otoacoustic emissions (TEOAEs) at high frequencies are a non-invasive physiological test of basilar membrane mechanics at the basal end, and have clinical potential to detect risk of hearing loss related to outer-hair-cell dysfunction. Using stimuli with constant incident pressure across frequency, TEOAEs were measured in experiment 1 at low frequencies (0.7-8 kHz) and high frequencies (7.1-14.7 kHz) in adults with normal hearing up to 8 kHz and varying hearing levels from 9 to 16 kHz. In combination with click stimuli, chirp stimuli were used with slow, medium and fast sweep rates for which the local frequency increased or decreased with time. Chirp TEOAEs were transformed into equivalent click TEOAEs by inverse filtering out chirp stimulus phase, and analyzed similarly to click TEOAEs. To improve detection above 8 kHz, TEOAEs were measured in experiment 2 with higher-level stimuli and longer averaging times. These changes increased the TEOAE signal-to-noise ratio (SNR) by 10 dB. Slower sweep rates were investigated but the elicited TEOAEs were detected in fewer ears compared to faster rates. Data were acquired in adults and children (age 11-17 y.), including children with cystic fibrosis (CF) treated with ototoxic antibiotics. Test-retest measurements revealed satisfactory repeatability of high-frequency TEOAE SNR (median of 1.3 dB) and coherence synchrony measure, despite small test-retest differences related to changes in forward and reverse transmission in the ear canal. The results suggest the potential use of such tests to screen for sensorineural hearing loss, including ototoxic loss. Experiment 2 was a feasibility study to explore TEOAE test parameters that might be used in a full-scale study to screen CF patients for risk of ototoxic hearing loss.

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via IFTTT

High frequency transient-evoked otoacoustic emission measurements using chirp and click stimuli

Publication date: Available online 18 October 2018

Source: Hearing Research

Author(s): Douglas H. Keefe, M. Patrick Feeney, Lisa L. Hunter, Denis F. Fitzpatrick, Chelsea M. Blankenship, Angela C. Garinis, Daniel B. Putterman, Marcin Wróblewski

Abstract

Transient-evoked otoacoustic emissions (TEOAEs) at high frequencies are a non-invasive physiological test of basilar membrane mechanics at the basal end, and have clinical potential to detect risk of hearing loss related to outer-hair-cell dysfunction. Using stimuli with constant incident pressure across frequency, TEOAEs were measured in experiment 1 at low frequencies (0.7-8 kHz) and high frequencies (7.1-14.7 kHz) in adults with normal hearing up to 8 kHz and varying hearing levels from 9 to 16 kHz. In combination with click stimuli, chirp stimuli were used with slow, medium and fast sweep rates for which the local frequency increased or decreased with time. Chirp TEOAEs were transformed into equivalent click TEOAEs by inverse filtering out chirp stimulus phase, and analyzed similarly to click TEOAEs. To improve detection above 8 kHz, TEOAEs were measured in experiment 2 with higher-level stimuli and longer averaging times. These changes increased the TEOAE signal-to-noise ratio (SNR) by 10 dB. Slower sweep rates were investigated but the elicited TEOAEs were detected in fewer ears compared to faster rates. Data were acquired in adults and children (age 11-17 y.), including children with cystic fibrosis (CF) treated with ototoxic antibiotics. Test-retest measurements revealed satisfactory repeatability of high-frequency TEOAE SNR (median of 1.3 dB) and coherence synchrony measure, despite small test-retest differences related to changes in forward and reverse transmission in the ear canal. The results suggest the potential use of such tests to screen for sensorineural hearing loss, including ototoxic loss. Experiment 2 was a feasibility study to explore TEOAE test parameters that might be used in a full-scale study to screen CF patients for risk of ototoxic hearing loss.

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