Effect of stimulus level on the temporal response properties of the auditory nerve in cochlear implants

Publication date: Available online 13 June 2017
Source:Hearing Research
Author(s): Michelle L. Hughes, Sarah A. Laurello
Electrically evoked compound action potentials (ECAPs) have been used to examine temporal response patterns of the auditory nerve in cochlear implant (CI) recipients. ECAP responses to individual pulses in a pulse train vary across stimulation rates for individual CI users. For very slow rates, auditory neurons have ample time to discharge, recover, and respond to each pulse in the train. As the pulse rate increases, an alternating ECAP-amplitude pattern occurs. As the stimulation rate increases further, the alternating pattern eventually ceases and the overall ECAP amplitudes are diminished, yielding a relatively stochastic state that presumably reflects a combination of adaptation, desynchronization, and facilitation across fibers. Because CIs operate over a range of current levels in everyday use, it is important to understand auditory-nerve responses to pulse trains over a range of levels. The effect of stimulus level on ECAP temporal response patterns in human CI users has not been well studied. The first goal of this study was to examine the effect of stimulus level on various aspects of ECAP temporal responses to pulse-train stimuli. Because higher stimulus levels yield more synchronous responses and faster recovery, it was hypothesized that: (1) the maximum alternation would occur at slower rates for lower levels and faster rates at higher levels, (2) the alternation depth at its maximum would be smaller for lower levels, (3) the rate that produces a stochastic state (‘stochastic rate’) would decrease with level, (4) adaptation would be greater for lower levels as a result of slower recovery, and (5) refractory-recovery time constants would be longer (slower) for lower levels, consistent with earlier studies. The second goal of this study was to examine how refractory-recovery time constants relate specifically to maximum alternation and stochastic rate. Data were collected for 12 ears in 10 CI recipients. ECAPs were recorded in response to each of 13 pulses in an equal-amplitude pulse train ranging in rate from 900–3500 pps for three levels (low, medium, high). The results generally supported hypotheses 1–4; there were no significant effects of level on the refractory-recovery time constants (hypothesis 5). When data were pooled across level, there was a significant negative correlation between alternation depth and refractory recovery time. Understanding the effects of stimulus level on auditory-nerve responses may provide further insight into improving the use of objective measures for potentially optimizing speech-processing strategies.



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Effect of stimulus level on the temporal response properties of the auditory nerve in cochlear implants

Publication date: Available online 13 June 2017
Source:Hearing Research
Author(s): Michelle L. Hughes, Sarah A. Laurello
Electrically evoked compound action potentials (ECAPs) have been used to examine temporal response patterns of the auditory nerve in cochlear implant (CI) recipients. ECAP responses to individual pulses in a pulse train vary across stimulation rates for individual CI users. For very slow rates, auditory neurons have ample time to discharge, recover, and respond to each pulse in the train. As the pulse rate increases, an alternating ECAP-amplitude pattern occurs. As the stimulation rate increases further, the alternating pattern eventually ceases and the overall ECAP amplitudes are diminished, yielding a relatively stochastic state that presumably reflects a combination of adaptation, desynchronization, and facilitation across fibers. Because CIs operate over a range of current levels in everyday use, it is important to understand auditory-nerve responses to pulse trains over a range of levels. The effect of stimulus level on ECAP temporal response patterns in human CI users has not been well studied. The first goal of this study was to examine the effect of stimulus level on various aspects of ECAP temporal responses to pulse-train stimuli. Because higher stimulus levels yield more synchronous responses and faster recovery, it was hypothesized that: (1) the maximum alternation would occur at slower rates for lower levels and faster rates at higher levels, (2) the alternation depth at its maximum would be smaller for lower levels, (3) the rate that produces a stochastic state (‘stochastic rate’) would decrease with level, (4) adaptation would be greater for lower levels as a result of slower recovery, and (5) refractory-recovery time constants would be longer (slower) for lower levels, consistent with earlier studies. The second goal of this study was to examine how refractory-recovery time constants relate specifically to maximum alternation and stochastic rate. Data were collected for 12 ears in 10 CI recipients. ECAPs were recorded in response to each of 13 pulses in an equal-amplitude pulse train ranging in rate from 900–3500 pps for three levels (low, medium, high). The results generally supported hypotheses 1–4; there were no significant effects of level on the refractory-recovery time constants (hypothesis 5). When data were pooled across level, there was a significant negative correlation between alternation depth and refractory recovery time. Understanding the effects of stimulus level on auditory-nerve responses may provide further insight into improving the use of objective measures for potentially optimizing speech-processing strategies.



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Effect of stimulus level on the temporal response properties of the auditory nerve in cochlear implants

Publication date: Available online 13 June 2017
Source:Hearing Research
Author(s): Michelle L. Hughes, Sarah A. Laurello
Electrically evoked compound action potentials (ECAPs) have been used to examine temporal response patterns of the auditory nerve in cochlear implant (CI) recipients. ECAP responses to individual pulses in a pulse train vary across stimulation rates for individual CI users. For very slow rates, auditory neurons have ample time to discharge, recover, and respond to each pulse in the train. As the pulse rate increases, an alternating ECAP-amplitude pattern occurs. As the stimulation rate increases further, the alternating pattern eventually ceases and the overall ECAP amplitudes are diminished, yielding a relatively stochastic state that presumably reflects a combination of adaptation, desynchronization, and facilitation across fibers. Because CIs operate over a range of current levels in everyday use, it is important to understand auditory-nerve responses to pulse trains over a range of levels. The effect of stimulus level on ECAP temporal response patterns in human CI users has not been well studied. The first goal of this study was to examine the effect of stimulus level on various aspects of ECAP temporal responses to pulse-train stimuli. Because higher stimulus levels yield more synchronous responses and faster recovery, it was hypothesized that: (1) the maximum alternation would occur at slower rates for lower levels and faster rates at higher levels, (2) the alternation depth at its maximum would be smaller for lower levels, (3) the rate that produces a stochastic state (‘stochastic rate’) would decrease with level, (4) adaptation would be greater for lower levels as a result of slower recovery, and (5) refractory-recovery time constants would be longer (slower) for lower levels, consistent with earlier studies. The second goal of this study was to examine how refractory-recovery time constants relate specifically to maximum alternation and stochastic rate. Data were collected for 12 ears in 10 CI recipients. ECAPs were recorded in response to each of 13 pulses in an equal-amplitude pulse train ranging in rate from 900–3500 pps for three levels (low, medium, high). The results generally supported hypotheses 1–4; there were no significant effects of level on the refractory-recovery time constants (hypothesis 5). When data were pooled across level, there was a significant negative correlation between alternation depth and refractory recovery time. Understanding the effects of stimulus level on auditory-nerve responses may provide further insight into improving the use of objective measures for potentially optimizing speech-processing strategies.



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Effect of stimulus level on the temporal response properties of the auditory nerve in cochlear implants

Publication date: Available online 13 June 2017
Source:Hearing Research
Author(s): Michelle L. Hughes, Sarah A. Laurello
Electrically evoked compound action potentials (ECAPs) have been used to examine temporal response patterns of the auditory nerve in cochlear implant (CI) recipients. ECAP responses to individual pulses in a pulse train vary across stimulation rates for individual CI users. For very slow rates, auditory neurons have ample time to discharge, recover, and respond to each pulse in the train. As the pulse rate increases, an alternating ECAP-amplitude pattern occurs. As the stimulation rate increases further, the alternating pattern eventually ceases and the overall ECAP amplitudes are diminished, yielding a relatively stochastic state that presumably reflects a combination of adaptation, desynchronization, and facilitation across fibers. Because CIs operate over a range of current levels in everyday use, it is important to understand auditory-nerve responses to pulse trains over a range of levels. The effect of stimulus level on ECAP temporal response patterns in human CI users has not been well studied. The first goal of this study was to examine the effect of stimulus level on various aspects of ECAP temporal responses to pulse-train stimuli. Because higher stimulus levels yield more synchronous responses and faster recovery, it was hypothesized that: (1) the maximum alternation would occur at slower rates for lower levels and faster rates at higher levels, (2) the alternation depth at its maximum would be smaller for lower levels, (3) the rate that produces a stochastic state (‘stochastic rate’) would decrease with level, (4) adaptation would be greater for lower levels as a result of slower recovery, and (5) refractory-recovery time constants would be longer (slower) for lower levels, consistent with earlier studies. The second goal of this study was to examine how refractory-recovery time constants relate specifically to maximum alternation and stochastic rate. Data were collected for 12 ears in 10 CI recipients. ECAPs were recorded in response to each of 13 pulses in an equal-amplitude pulse train ranging in rate from 900–3500 pps for three levels (low, medium, high). The results generally supported hypotheses 1–4; there were no significant effects of level on the refractory-recovery time constants (hypothesis 5). When data were pooled across level, there was a significant negative correlation between alternation depth and refractory recovery time. Understanding the effects of stimulus level on auditory-nerve responses may provide further insight into improving the use of objective measures for potentially optimizing speech-processing strategies.



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Effect of stimulus level on the temporal response properties of the auditory nerve in cochlear implants

Publication date: Available online 13 June 2017
Source:Hearing Research
Author(s): Michelle L. Hughes, Sarah A. Laurello
Electrically evoked compound action potentials (ECAPs) have been used to examine temporal response patterns of the auditory nerve in cochlear implant (CI) recipients. ECAP responses to individual pulses in a pulse train vary across stimulation rates for individual CI users. For very slow rates, auditory neurons have ample time to discharge, recover, and respond to each pulse in the train. As the pulse rate increases, an alternating ECAP-amplitude pattern occurs. As the stimulation rate increases further, the alternating pattern eventually ceases and the overall ECAP amplitudes are diminished, yielding a relatively stochastic state that presumably reflects a combination of adaptation, desynchronization, and facilitation across fibers. Because CIs operate over a range of current levels in everyday use, it is important to understand auditory-nerve responses to pulse trains over a range of levels. The effect of stimulus level on ECAP temporal response patterns in human CI users has not been well studied. The first goal of this study was to examine the effect of stimulus level on various aspects of ECAP temporal responses to pulse-train stimuli. Because higher stimulus levels yield more synchronous responses and faster recovery, it was hypothesized that: (1) the maximum alternation would occur at slower rates for lower levels and faster rates at higher levels, (2) the alternation depth at its maximum would be smaller for lower levels, (3) the rate that produces a stochastic state (‘stochastic rate’) would decrease with level, (4) adaptation would be greater for lower levels as a result of slower recovery, and (5) refractory-recovery time constants would be longer (slower) for lower levels, consistent with earlier studies. The second goal of this study was to examine how refractory-recovery time constants relate specifically to maximum alternation and stochastic rate. Data were collected for 12 ears in 10 CI recipients. ECAPs were recorded in response to each of 13 pulses in an equal-amplitude pulse train ranging in rate from 900–3500 pps for three levels (low, medium, high). The results generally supported hypotheses 1–4; there were no significant effects of level on the refractory-recovery time constants (hypothesis 5). When data were pooled across level, there was a significant negative correlation between alternation depth and refractory recovery time. Understanding the effects of stimulus level on auditory-nerve responses may provide further insight into improving the use of objective measures for potentially optimizing speech-processing strategies.



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Suprameatal Cochlear Implantation in a CHARGE Patient With a Novel CHD7 Variant and KALLMANN Syndrome Phenotype: A Case Report.

Objective: We present the clinical findings, technique of the suprameatal cochlear implantation, postoperative auditory results, and genetic analysis of the CHD7 gene. Patient: A 19-year-old Japanese woman was referred because of progressive hearing loss since early childhood. She had used verbal language for the main mode of communication until the age of 17. Examination revealed coloboma, heart defect, choanal atresia, genital hypoplasia, and deafness, which was diagnosed as CHARGE syndrome. Examination also revealed features of Kallmann syndrome. Interventions: Cochlear implantation was performed in the left ear at age 20. Targeted resequencing of the CHD7 gene was performed by next-generation sequencing. Results: Cochlear implantation was performed using a suprameatal approach (SMA) with cartilage protection because of a venous malformation of the temporal bone. The electrode introduced into the scala tympani through the cochleostomy could be fully inserted. The electrode was covered with cartilage to avoid contact with the skin of the external auditory canal. No intra- or postoperative complications have occurred up to 4 years postoperatively, and the patient uses verbal language again as the main mode of communication. A novel variant c.6405_6406delAG,p.(Ala2137Argfs*2) in CHD7 was identified by next-generation and Sanger sequencing analyses, resulting in a 2137-amino-acid truncated polypeptide. Parental genetic screening confirmed the sporadic origin of the mutation. Conclusion: Cochlear implantation surgery using the SMA with cartilage protection technique appears to be a feasible and effective option for patients with ear anomalies that obstruct the usual approach. A novel frameshift variant c.6405_6406delAG,p.(Ala2137Argfs*2) in CHD7 was also identified in this patient. Copyright (C) 2017 by Otology & Neurotology, Inc. Image copyright (C) 2010 Wolters Kluwer Health/Anatomical Chart Company

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A Comparison of Coverbal Gesture Use in Oral Discourse Among Speakers With Fluent and Nonfluent Aphasia

Purpose

Coverbal gesture use, which is affected by the presence and degree of aphasia, can be culturally specific. The purpose of this study was to compare gesture use among Cantonese-speaking individuals: 23 neurologically healthy speakers, 23 speakers with fluent aphasia, and 21 speakers with nonfluent aphasia.

Method

Multimedia data of discourse samples from these speakers were extracted from the Cantonese AphasiaBank. Gestures were independently annotated on their forms and functions to determine how gesturing rate and distribution of gestures differed across speaker groups. A multiple regression was conducted to determine the most predictive variable(s) for gesture-to-word ratio.

Results

Although speakers with nonfluent aphasia gestured most frequently, the rate of gesture use in counterparts with fluent aphasia did not differ significantly from controls. Different patterns of gesture functions in the 3 speaker groups revealed that gesture plays a minor role in lexical retrieval whereas its role in enhancing communication dominates among the speakers with aphasia. The percentages of complete sentences and dysfluency strongly predicted the gesturing rate in aphasia.

Conclusions

The current results supported the sketch model of language–gesture association. The relationship between gesture production and linguistic abilities and clinical implications for gesture-based language intervention for speakers with aphasia are also discussed.

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Automated Assessment of Child Vocalization Development Using LENA

Purpose

To produce a novel, efficient measure of children's expressive vocal development on the basis of automatic vocalization assessment (AVA), child vocalizations were automatically identified and extracted from audio recordings using Language Environment Analysis (LENA) System technology.

Method

Assessment was based on full-day audio recordings collected in a child's unrestricted, natural language environment. AVA estimates were derived using automatic speech recognition modeling techniques to categorize and quantify the sounds in child vocalizations (e.g., protophones and phonemes). These were expressed as phone and biphone frequencies, reduced to principal components, and inputted to age-based multiple linear regression models to predict independently collected criterion-expressive language scores. From these models, we generated vocal development AVA estimates as age-standardized scores and development age estimates.

Result

AVA estimates demonstrated strong statistical reliability and validity when compared with standard criterion expressive language assessments.

Conclusions

Automated analysis of child vocalizations extracted from full-day recordings in natural settings offers a novel and efficient means to assess children's expressive vocal development. More research remains to identify specific mechanisms of operation.

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Speech-Processing Fatigue in Children: Auditory Event-Related Potential and Behavioral Measures

Purpose

Fatigue related to speech processing is an understudied area that may have significant negative effects, especially in children who spend the majority of their school days listening to classroom instruction.

Method

This study examined the feasibility of using auditory P300 responses and behavioral indices (lapses of attention and self-report) to measure fatigue resulting from sustained listening demands in 27 children (M = 9.28 years).

Results

Consistent with predictions, increased lapses of attention, longer reaction times, reduced P300 amplitudes to infrequent target stimuli, and self-report of greater fatigue were observed after the completion of a series of demanding listening tasks compared with the baseline values. The event-related potential responses correlated with the behavioral measures of performance.

Conclusion

These findings suggest that neural and behavioral responses indexing attention and processing resources show promise as effective markers of fatigue in children.

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A Comparison of Coverbal Gesture Use in Oral Discourse Among Speakers With Fluent and Nonfluent Aphasia

Purpose

Coverbal gesture use, which is affected by the presence and degree of aphasia, can be culturally specific. The purpose of this study was to compare gesture use among Cantonese-speaking individuals: 23 neurologically healthy speakers, 23 speakers with fluent aphasia, and 21 speakers with nonfluent aphasia.

Method

Multimedia data of discourse samples from these speakers were extracted from the Cantonese AphasiaBank. Gestures were independently annotated on their forms and functions to determine how gesturing rate and distribution of gestures differed across speaker groups. A multiple regression was conducted to determine the most predictive variable(s) for gesture-to-word ratio.

Results

Although speakers with nonfluent aphasia gestured most frequently, the rate of gesture use in counterparts with fluent aphasia did not differ significantly from controls. Different patterns of gesture functions in the 3 speaker groups revealed that gesture plays a minor role in lexical retrieval whereas its role in enhancing communication dominates among the speakers with aphasia. The percentages of complete sentences and dysfluency strongly predicted the gesturing rate in aphasia.

Conclusions

The current results supported the sketch model of language–gesture association. The relationship between gesture production and linguistic abilities and clinical implications for gesture-based language intervention for speakers with aphasia are also discussed.

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Automated Assessment of Child Vocalization Development Using LENA

Purpose

To produce a novel, efficient measure of children's expressive vocal development on the basis of automatic vocalization assessment (AVA), child vocalizations were automatically identified and extracted from audio recordings using Language Environment Analysis (LENA) System technology.

Method

Assessment was based on full-day audio recordings collected in a child's unrestricted, natural language environment. AVA estimates were derived using automatic speech recognition modeling techniques to categorize and quantify the sounds in child vocalizations (e.g., protophones and phonemes). These were expressed as phone and biphone frequencies, reduced to principal components, and inputted to age-based multiple linear regression models to predict independently collected criterion-expressive language scores. From these models, we generated vocal development AVA estimates as age-standardized scores and development age estimates.

Result

AVA estimates demonstrated strong statistical reliability and validity when compared with standard criterion expressive language assessments.

Conclusions

Automated analysis of child vocalizations extracted from full-day recordings in natural settings offers a novel and efficient means to assess children's expressive vocal development. More research remains to identify specific mechanisms of operation.

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Speech-Processing Fatigue in Children: Auditory Event-Related Potential and Behavioral Measures

Purpose

Fatigue related to speech processing is an understudied area that may have significant negative effects, especially in children who spend the majority of their school days listening to classroom instruction.

Method

This study examined the feasibility of using auditory P300 responses and behavioral indices (lapses of attention and self-report) to measure fatigue resulting from sustained listening demands in 27 children (M = 9.28 years).

Results

Consistent with predictions, increased lapses of attention, longer reaction times, reduced P300 amplitudes to infrequent target stimuli, and self-report of greater fatigue were observed after the completion of a series of demanding listening tasks compared with the baseline values. The event-related potential responses correlated with the behavioral measures of performance.

Conclusion

These findings suggest that neural and behavioral responses indexing attention and processing resources show promise as effective markers of fatigue in children.

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A Comparison of Coverbal Gesture Use in Oral Discourse Among Speakers With Fluent and Nonfluent Aphasia

Purpose

Coverbal gesture use, which is affected by the presence and degree of aphasia, can be culturally specific. The purpose of this study was to compare gesture use among Cantonese-speaking individuals: 23 neurologically healthy speakers, 23 speakers with fluent aphasia, and 21 speakers with nonfluent aphasia.

Method

Multimedia data of discourse samples from these speakers were extracted from the Cantonese AphasiaBank. Gestures were independently annotated on their forms and functions to determine how gesturing rate and distribution of gestures differed across speaker groups. A multiple regression was conducted to determine the most predictive variable(s) for gesture-to-word ratio.

Results

Although speakers with nonfluent aphasia gestured most frequently, the rate of gesture use in counterparts with fluent aphasia did not differ significantly from controls. Different patterns of gesture functions in the 3 speaker groups revealed that gesture plays a minor role in lexical retrieval whereas its role in enhancing communication dominates among the speakers with aphasia. The percentages of complete sentences and dysfluency strongly predicted the gesturing rate in aphasia.

Conclusions

The current results supported the sketch model of language–gesture association. The relationship between gesture production and linguistic abilities and clinical implications for gesture-based language intervention for speakers with aphasia are also discussed.

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Automated Assessment of Child Vocalization Development Using LENA

Purpose

To produce a novel, efficient measure of children's expressive vocal development on the basis of automatic vocalization assessment (AVA), child vocalizations were automatically identified and extracted from audio recordings using Language Environment Analysis (LENA) System technology.

Method

Assessment was based on full-day audio recordings collected in a child's unrestricted, natural language environment. AVA estimates were derived using automatic speech recognition modeling techniques to categorize and quantify the sounds in child vocalizations (e.g., protophones and phonemes). These were expressed as phone and biphone frequencies, reduced to principal components, and inputted to age-based multiple linear regression models to predict independently collected criterion-expressive language scores. From these models, we generated vocal development AVA estimates as age-standardized scores and development age estimates.

Result

AVA estimates demonstrated strong statistical reliability and validity when compared with standard criterion expressive language assessments.

Conclusions

Automated analysis of child vocalizations extracted from full-day recordings in natural settings offers a novel and efficient means to assess children's expressive vocal development. More research remains to identify specific mechanisms of operation.

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Speech-Processing Fatigue in Children: Auditory Event-Related Potential and Behavioral Measures

Purpose

Fatigue related to speech processing is an understudied area that may have significant negative effects, especially in children who spend the majority of their school days listening to classroom instruction.

Method

This study examined the feasibility of using auditory P300 responses and behavioral indices (lapses of attention and self-report) to measure fatigue resulting from sustained listening demands in 27 children (M = 9.28 years).

Results

Consistent with predictions, increased lapses of attention, longer reaction times, reduced P300 amplitudes to infrequent target stimuli, and self-report of greater fatigue were observed after the completion of a series of demanding listening tasks compared with the baseline values. The event-related potential responses correlated with the behavioral measures of performance.

Conclusion

These findings suggest that neural and behavioral responses indexing attention and processing resources show promise as effective markers of fatigue in children.

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Analysis of Pressure Distribution During Direct Microlaryngoscopy

Publication date: Available online 12 June 2017
Source:Journal of Voice
Author(s): Busheng Tong, Rui Fang
ObjectiveThis study aimed to investigate the pressure distribution during direct microlaryngoscopy and its relation with the positioning of the patient.Study DesignThis is a prospective study in cadavers.Materials and MethodsThe pressure distribution during direct microlaryngoscopy was investigated in five adult fresh cadavers by using matrix-based piezoresistive thin-film sensors. The pressure among three head and neck positions (extension-extension, neutral, and flexion-extension) was studied.ResultsThe real-time pressure and its distribution were recorded as 3-D contours. The map commonly showed two peak pressure points, with one focused on the middle of the laryngoscope (peak pressure 1) and the other one focused on the distal part of the laryngoscope (peak pressure 2). The mean average pressure in this study was 38 ± 13 kPa, and the flexion-extension position had the lowest average pressure and peak pressure. However, the average pressure and peak pressure 1 showed no significant difference among the three positions (P > 0.05); peak pressure 2 in the flexion-extension position was significantly lower than that in the extension-extension position (P = 0.024) and the neutral position (P = 0.020).ConclusionsThe results of this study indicate that the flexion-extension position induced lower pressure exerted on the laryngoscope and is an optimal position for direct microlaryngoscopy. Hyoid bone may play an important role in the pressure exerted.



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Autophagy in the Vertebrate Inner Ear.

Related Articles

Autophagy in the Vertebrate Inner Ear.

Front Cell Dev Biol. 2017;5:56

Authors: Magariños M, Pulido S, Aburto MR, de Iriarte Rodríguez R, Varela-Nieto I

Abstract
Autophagy is a conserved catabolic process that results in the lysosomal degradation of cell components. During development, autophagy is associated with tissue and organ remodeling, and under physiological conditions it is tightly regulated as it plays a housekeeping role in removing misfolded proteins and damaged organelles. The vertebrate inner ear is a complex sensory organ responsible for the perception of sound and for balance. Cell survival, death and proliferation, as well as cell fate specification and differentiation, are processes that are strictly coordinated during the development of the inner ear in order to generate the more than a dozen specialized cell types that constitute this structure. Here, we review the existing evidence that implicates autophagy in the generation of the vertebrate inner ear. At early stages of chicken otic development, inhibiting autophagy impairs neurogenesis and causes aberrant otocyst morphogenesis. Autophagy provides energy for the clearing of dying cells and it favors neuronal differentiation. Moreover, autophagy is required for proper vestibular development in the mouse inner ear. The autophagy-related genes Becn1, Atg4g, Atg5, and Atg9, are expressed in the inner ear from late developmental stages to adulthood, and Atg4b mutants show impaired vestibular behavior associated to defects in otoconial biogenesis that are also common to Atg5 mutants. Autophagic flux appears to be age-regulated, augmenting from perinatal stages to young adulthood in mice. This up-regulation is concomitant with the functional maturation of the hearing receptor. Hence, autophagy can be considered an intracellular pathway fundamental for in vertebrate inner ear development and maturation.

PMID: 28603711 [PubMed - in process]

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Autophagy in the Vertebrate Inner Ear.

Related Articles

Autophagy in the Vertebrate Inner Ear.

Front Cell Dev Biol. 2017;5:56

Authors: Magariños M, Pulido S, Aburto MR, de Iriarte Rodríguez R, Varela-Nieto I

Abstract
Autophagy is a conserved catabolic process that results in the lysosomal degradation of cell components. During development, autophagy is associated with tissue and organ remodeling, and under physiological conditions it is tightly regulated as it plays a housekeeping role in removing misfolded proteins and damaged organelles. The vertebrate inner ear is a complex sensory organ responsible for the perception of sound and for balance. Cell survival, death and proliferation, as well as cell fate specification and differentiation, are processes that are strictly coordinated during the development of the inner ear in order to generate the more than a dozen specialized cell types that constitute this structure. Here, we review the existing evidence that implicates autophagy in the generation of the vertebrate inner ear. At early stages of chicken otic development, inhibiting autophagy impairs neurogenesis and causes aberrant otocyst morphogenesis. Autophagy provides energy for the clearing of dying cells and it favors neuronal differentiation. Moreover, autophagy is required for proper vestibular development in the mouse inner ear. The autophagy-related genes Becn1, Atg4g, Atg5, and Atg9, are expressed in the inner ear from late developmental stages to adulthood, and Atg4b mutants show impaired vestibular behavior associated to defects in otoconial biogenesis that are also common to Atg5 mutants. Autophagic flux appears to be age-regulated, augmenting from perinatal stages to young adulthood in mice. This up-regulation is concomitant with the functional maturation of the hearing receptor. Hence, autophagy can be considered an intracellular pathway fundamental for in vertebrate inner ear development and maturation.

PMID: 28603711 [PubMed - in process]

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Pain After Cochlear Implantation: An Unusual Complication?.

Objective: To analyze clinical signs and better define the underestimated long-term pain after implantation, to discuss etiological hypothesis, and to propose our department treatment algorithm and results. Study Design and Setting: Retrospective review of children implanted with complaints of atypical pain in the area of device implantation, not in the immediate postoperative period, more than or equal to 4 on the Visual Analog Pain Scale (VAPS: 0-10) in the ENT pediatric department of Trousseau and Necker Enfants Malades Hospitals between 1998 and 2015. Patients: All patients had full clinical and electrophysiological checking, and had normal functioning device. Exclusion criteria were: related history of local trauma, ongoing skin infection, magnet displacement, and device failure. Intervention(s): Treatments and outcomes were reviewed, with a minimum of 6 months follow up. Two groups were analyzed: Group PS: pain associated with local swelling (n = 9) and Group P: isolated pain (n = 11). The first-line treatment was medical. In Group PS, anti-inflammatory, pain medication, and antibiotics were used at the same time; in Group P, only anti-inflammatory and pain medication was used. Main Outcome Measure(s): Success was defined when complete resolution of pain and swelling (pain scale = 0). Results: Twenty cases out of the 1,448 implanted patients in our department (1.4%) were included. Average age at first occurrence of pain was 15 years (3-22 yr). Mean delay between surgery and pain complaint was 5.8 years (0.25-14). Mean follow up was 2 years (0.5-5 yr). First line medical treatment was successful in eight cases (40%). Of the 12 patients who failed medical treatment and required surgery, two had resolution of pain with magnet change and 10 had resolution with reimplantation. (5/9 patients in Group PS and 7/11 in Group P). Microbiology was performed in 10/20 cases and analysis of explanted devices was performed in 7/10 cases. Positive microbiological culture of soft tissues was positive for 3/10 cases, biofilm was positive for 5/7 cases. Pain in the area of the implanted device can occur shortly after surgery or on long-term follow up. It has been seen in all device types. Pain may be clinically underestimated, as low VAPS grade (

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Long-term Outcomes of Cochlear Implantation in Children With Congenital Cytomegalovirus Infection.

Objective: To investigate the role of the developmental delay often observed in children with congenital cytomegalovirus (CMV) infection on the improvement of language understanding after cochlear implantation (CI). Study Design: Retrospective chart review. Patients: Sixteen children with severe and/or profound hearing loss due to congenital CMV infection (CMV group) and 107 congenitally deaf children (168 ears) without CMV infection as the cause of deafness (non-CMV group). Mean age at which patients underwent CI was 2.9 years in both groups. The mean follow-up period was 7.8 versus 8.2 years, respectively. Interventions/Main Outcome Measures: The Enjoji Scale of Infant Analytical Development was used to evaluate/compare pre- and postoperative hearing level, word recognition score, speech discrimination score, and language production and perception skills. The Picture Vocabulary Test-Revised was used to assess vocabulary understanding skill. Correlation between the final vocabulary understanding skill assessment and several factors was also examined. Results: Improvement in hearing thresholds (mean: 106.0 dB) was greater after the first CI, (27-45 dB; mean: 33.8 dB) compared with hearing aid (48-74 dB; mean: 63.1 dB). Similarly, language perception and production were better in the CMV group. However, in the long term, differences between good and poor cases became prominent, especially in children with motor or cognitive delay and brain abnormalities who performed poorly in the CMV group. Conclusion: Long-term language perception and production after CI were overall satisfactory in congenital CMV-deafened children. CI was effective, particularly in the absence of CMV-induced disorders. However, this effectiveness was limited in those with motor or cognitive delay. Copyright (C) 2017 by Otology & Neurotology, Inc. Image copyright (C) 2010 Wolters Kluwer Health/Anatomical Chart Company

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How to Avoid a Learning Curve in Stapedotomy: A Standardized Surgical Technique.

Objective: To evaluate, whether a learning curve for beginners in stapedotomy can be avoided by using a prosthesis with thermal memory-shape attachment in combination with a standardized laser-assisted surgical technique. Study Design: Retrospective case review. Setting: Tertiary referral center. Patients: Fifty-eight ears were operated by three experienced surgeons and compared with a group of 12 cases operated by a beginner in stapedotomy. Intervention: Stapedotomy. Main Outcome Measures: Difference of pure-tone audiometry thresholds measured before and after surgery. Results: The average postoperative gain for air conduction in the frequencies below 2 kHz was 20 to 25 dB and decreased for the higher frequencies. Using the Mann-Whitney-U test for comparing mean gain between experienced and inexperienced surgeons showed no significant difference (p = 0.281 at 4 kHz and p > 0.7 for the other frequencies). A Spearman rank correlation of the postoperative gain for air- and bone-conduction thresholds was obtained at each test frequency for the first 12 patients consecutively treated with a thermal memory-shape attachment prosthesis by two experienced and one inexperienced surgeon. This analysis does not support the hypothesis of a "learning effect" that should be associated with an improved outcome for successively treated patients. Conclusion: It is possible to avoid a learning curve in stapes surgery by applying a thermal memory-shape prosthesis in a standardized laser-assisted surgical procedure. Copyright (C) 2017 by Otology & Neurotology, Inc. Image copyright (C) 2010 Wolters Kluwer Health/Anatomical Chart Company

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Diagnosing Large Vestibular Aqueduct: Radiological Review of High-Resolution CT Versus High-Resolution Volumetric MRI.

Objectives: To compare the diagnostic yield of high-resolution volumetric T2-weighted MRI (HRT2-MRI) with high-resolution computed tomography (HRCT) for diagnosis of large vestibular aqueduct (LVA). Study Design: Three board-certified neuroradiologists performed an independent, blinded radiological review for diagnosing LVA with 2:1 age-matched controls on patients with both HRCT and HRT2-MRI imaging. Setting: Tertiary referral center. Patients: All patients between 2002 and 2016 with hearing loss who underwent both HRCT and HRT2-MRI and were diagnosed with LVA on either modality. Main Outcome Measures: Concordance rate for LVA between HRCT and HRT2-MRI. Results: Concordance rate for HRCT and HRT2-MRI for diagnosing LVA was 88% (124/141) when assessing both the midpoint and external aperture diameters. Fifteen ears had LVA on computed tomography (CT), but not on magnetic resonance imaging (MRI); in comparison, two ears had LVA on MRI, but not on CT (p = 0.002). Excellent inter-rater reliability among the three radiologists was demonstrated. Conclusion: Historically, HRCT has been the imaging modality of choice for diagnosing LVA. Although a higher concordance rate of HRT2-MRI was found compared with previous studies utilizing earlier MRI technology, HRCT still detected a larger number of patients with clinically significant hearing loss compared with MRI. Given the high concordance rate and efficacy of both modalities in diagnosing LVA, the ultimate decision of which modality to choose may depend on other patient-specific and clinical factors. Copyright (C) 2017 by Otology & Neurotology, Inc. Image copyright (C) 2010 Wolters Kluwer Health/Anatomical Chart Company

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