Effects of Within-Talker Variability on Speech Intelligibility in Mandarin-Speaking Adult and Pediatric Cochlear Implant Patients

Cochlear implant (CI) speech performance is typically evaluated using well-enunciated speech produced at a normal rate by a single talker. CI users often have greater difficulty with variations in speech production encountered in everyday listening. Within a single talker, speaking rate, amplitude, duration, and voice pitch information may be quite variable, depending on the production context. The coarse spectral resolution afforded by the CI limits perception of voice pitch, which is an important cue for speech prosody and for tonal languages such as Mandarin Chinese. In this study, sentence recognition from the Mandarin speech perception database was measured in adult and pediatric Mandarin-speaking CI listeners for a variety of speaking styles: voiced speech produced at slow, normal, and fast speaking rates; whispered speech; voiced emotional speech; and voiced shouted speech. Recognition of Mandarin Hearing in Noise Test sentences was also measured. Results showed that performance was significantly poorer with whispered speech relative to the other speaking styles and that performance was significantly better with slow speech than with fast or emotional speech. Results also showed that adult and pediatric performance was significantly poorer with Mandarin Hearing in Noise Test than with Mandarin speech perception sentences at the normal rate. The results suggest that adult and pediatric Mandarin-speaking CI patients are highly susceptible to whispered speech, due to the lack of lexically important voice pitch cues and perhaps other qualities associated with whispered speech. The results also suggest that test materials may contribute to differences in performance observed between adult and pediatric CI users.

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Effects of Within-Talker Variability on Speech Intelligibility in Mandarin-Speaking Adult and Pediatric Cochlear Implant Patients

Cochlear implant (CI) speech performance is typically evaluated using well-enunciated speech produced at a normal rate by a single talker. CI users often have greater difficulty with variations in speech production encountered in everyday listening. Within a single talker, speaking rate, amplitude, duration, and voice pitch information may be quite variable, depending on the production context. The coarse spectral resolution afforded by the CI limits perception of voice pitch, which is an important cue for speech prosody and for tonal languages such as Mandarin Chinese. In this study, sentence recognition from the Mandarin speech perception database was measured in adult and pediatric Mandarin-speaking CI listeners for a variety of speaking styles: voiced speech produced at slow, normal, and fast speaking rates; whispered speech; voiced emotional speech; and voiced shouted speech. Recognition of Mandarin Hearing in Noise Test sentences was also measured. Results showed that performance was significantly poorer with whispered speech relative to the other speaking styles and that performance was significantly better with slow speech than with fast or emotional speech. Results also showed that adult and pediatric performance was significantly poorer with Mandarin Hearing in Noise Test than with Mandarin speech perception sentences at the normal rate. The results suggest that adult and pediatric Mandarin-speaking CI patients are highly susceptible to whispered speech, due to the lack of lexically important voice pitch cues and perhaps other qualities associated with whispered speech. The results also suggest that test materials may contribute to differences in performance observed between adult and pediatric CI users.

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Effects of Within-Talker Variability on Speech Intelligibility in Mandarin-Speaking Adult and Pediatric Cochlear Implant Patients

Cochlear implant (CI) speech performance is typically evaluated using well-enunciated speech produced at a normal rate by a single talker. CI users often have greater difficulty with variations in speech production encountered in everyday listening. Within a single talker, speaking rate, amplitude, duration, and voice pitch information may be quite variable, depending on the production context. The coarse spectral resolution afforded by the CI limits perception of voice pitch, which is an important cue for speech prosody and for tonal languages such as Mandarin Chinese. In this study, sentence recognition from the Mandarin speech perception database was measured in adult and pediatric Mandarin-speaking CI listeners for a variety of speaking styles: voiced speech produced at slow, normal, and fast speaking rates; whispered speech; voiced emotional speech; and voiced shouted speech. Recognition of Mandarin Hearing in Noise Test sentences was also measured. Results showed that performance was significantly poorer with whispered speech relative to the other speaking styles and that performance was significantly better with slow speech than with fast or emotional speech. Results also showed that adult and pediatric performance was significantly poorer with Mandarin Hearing in Noise Test than with Mandarin speech perception sentences at the normal rate. The results suggest that adult and pediatric Mandarin-speaking CI patients are highly susceptible to whispered speech, due to the lack of lexically important voice pitch cues and perhaps other qualities associated with whispered speech. The results also suggest that test materials may contribute to differences in performance observed between adult and pediatric CI users.

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A Two-Year Randomized Trial of Interventions to Decrease Stress Hormone Vasopressin Production in Patients with Meniere’s Disease—A Pilot Study

by Tadashi Kitahara, Hidehiko Okamoto, Munehisa Fukushima, Masaharu Sakagami, Taeko Ito, Akinori Yamashita, Ichiro Ota, Toshiaki Yamanaka

Meniere's disease, a common inner ear condition, has an incidence of 15–50 per 100,000. Because mental/physical stress and subsequent increase in the stress hormone vasopressin supposedly trigger Meniere's disease, we set a pilot study to seek new therapeutic interventions, namely management of vasopressin secretion, to treat this disease. We enrolled 297 definite Meniere's patients from 2010 to 2012 in a randomized-controlled and open-label trial, assigning Group-I (control) traditional oral medication, Group-II abundant water intake, Group-III tympanic ventilation tubes and Group-IV sleeping in darkness. Two hundred sixty-three patients completed the planned 2-year-follow-up, which included assessment of vertigo, hearing, plasma vasopressin concentrations and changes in stress/psychological factors. At 2 years, vertigo was completely controlled in 54.3% of patients in Group-I, 81.4% in Group-II, 84.1% in Group-III, and 80.0% in Group-IV (statistically I Trial Registration: ClinicalTrials.gov NCT01099046

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Initial Stop Voicing in Bilingual Children With Cochlear Implants and Their Typically Developing Peers With Normal Hearing

Purpose

This study focuses on stop voicing differentiation in bilingual children with normal hearing (NH) and their bilingual peers with hearing loss who use cochlear implants (CIs).

Method

Twenty-two bilingual children participated in our study (11 with NH, M age = 5;1 [years;months], and 11 with CIs, M hearing age = 5;1). The groups were matched on hearing age and a range of demographic variables. Single-word picture elicitation was used with word-initial singleton stop consonants. Repeated measures analyses of variance with three within-subject factors (language, stop voicing, and stop place of articulation) and one between-subjects factor (NH vs. CI user) were conducted with voice onset time and percentage of prevoiced stops as dependent variables.

Results

Main effects were statistically significant for language, stop voicing, and stop place of articulation on both voice onset time and prevoicing. There were no significant main effects for NH versus CI groups. Both children with NH and with CIs differentiated stop voicing in their languages and by stop place of articulation. Stop voicing differentiation was commensurate across the groups of children with NH versus CIs.

Conclusions

Stop voicing differentiation is accomplished in a similar fashion by bilingual children with NH and CIs, and both groups differentiate stop voicing in a language-specific fashion.

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Initial Stop Voicing in Bilingual Children With Cochlear Implants and Their Typically Developing Peers With Normal Hearing

Purpose

This study focuses on stop voicing differentiation in bilingual children with normal hearing (NH) and their bilingual peers with hearing loss who use cochlear implants (CIs).

Method

Twenty-two bilingual children participated in our study (11 with NH, M age = 5;1 [years;months], and 11 with CIs, M hearing age = 5;1). The groups were matched on hearing age and a range of demographic variables. Single-word picture elicitation was used with word-initial singleton stop consonants. Repeated measures analyses of variance with three within-subject factors (language, stop voicing, and stop place of articulation) and one between-subjects factor (NH vs. CI user) were conducted with voice onset time and percentage of prevoiced stops as dependent variables.

Results

Main effects were statistically significant for language, stop voicing, and stop place of articulation on both voice onset time and prevoicing. There were no significant main effects for NH versus CI groups. Both children with NH and with CIs differentiated stop voicing in their languages and by stop place of articulation. Stop voicing differentiation was commensurate across the groups of children with NH versus CIs.

Conclusions

Stop voicing differentiation is accomplished in a similar fashion by bilingual children with NH and CIs, and both groups differentiate stop voicing in a language-specific fashion.

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Initial Stop Voicing in Bilingual Children With Cochlear Implants and Their Typically Developing Peers With Normal Hearing

Purpose

This study focuses on stop voicing differentiation in bilingual children with normal hearing (NH) and their bilingual peers with hearing loss who use cochlear implants (CIs).

Method

Twenty-two bilingual children participated in our study (11 with NH, M age = 5;1 [years;months], and 11 with CIs, M hearing age = 5;1). The groups were matched on hearing age and a range of demographic variables. Single-word picture elicitation was used with word-initial singleton stop consonants. Repeated measures analyses of variance with three within-subject factors (language, stop voicing, and stop place of articulation) and one between-subjects factor (NH vs. CI user) were conducted with voice onset time and percentage of prevoiced stops as dependent variables.

Results

Main effects were statistically significant for language, stop voicing, and stop place of articulation on both voice onset time and prevoicing. There were no significant main effects for NH versus CI groups. Both children with NH and with CIs differentiated stop voicing in their languages and by stop place of articulation. Stop voicing differentiation was commensurate across the groups of children with NH versus CIs.

Conclusions

Stop voicing differentiation is accomplished in a similar fashion by bilingual children with NH and CIs, and both groups differentiate stop voicing in a language-specific fashion.

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Minimal Hearing Loss: From a Failure-Based Approach to Evidence-Based Practice

Purpose

A representative sample of the literature on minimal hearing loss (MHL) was reviewed to provide evidence of challenges faced by children with MHL and to establish the need for evidence-based options for early intervention.

Method

Research articles published from 1950 to 2013 were searched in the Medline database using the keywords minimal hearing loss, unilateral hearing loss, and mild hearing loss. References cited in retrieved articles were also reviewed.

Results

In total, 69 articles contained relevant information about pediatric outcomes and/or intervention for unilateral hearing loss, 50 for mild hearing loss, and 6 for high-frequency hearing loss. Six challenges associated with MHL emerged, and 6 interventions were indicated. Evidence indicates that although some individuals may appear to have no observable speech-language or academic difficulties, others experience considerable difficulties. It also indicates that even though children with MHL may appear to catch up in some areas, difficulties in select domains continue into adulthood.

Conclusions

Evidence indicates significant risks associated with untreated MHL. Evidence also demonstrates the need for early intervention and identifies several appropriate intervention strategies; however, no single protocol is appropriate for all children. Therefore, families should be educated about the impact of MHL and about available interventions so that informed decisions can be made.

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Minimal Hearing Loss: From a Failure-Based Approach to Evidence-Based Practice

Purpose

A representative sample of the literature on minimal hearing loss (MHL) was reviewed to provide evidence of challenges faced by children with MHL and to establish the need for evidence-based options for early intervention.

Method

Research articles published from 1950 to 2013 were searched in the Medline database using the keywords minimal hearing loss, unilateral hearing loss, and mild hearing loss. References cited in retrieved articles were also reviewed.

Results

In total, 69 articles contained relevant information about pediatric outcomes and/or intervention for unilateral hearing loss, 50 for mild hearing loss, and 6 for high-frequency hearing loss. Six challenges associated with MHL emerged, and 6 interventions were indicated. Evidence indicates that although some individuals may appear to have no observable speech-language or academic difficulties, others experience considerable difficulties. It also indicates that even though children with MHL may appear to catch up in some areas, difficulties in select domains continue into adulthood.

Conclusions

Evidence indicates significant risks associated with untreated MHL. Evidence also demonstrates the need for early intervention and identifies several appropriate intervention strategies; however, no single protocol is appropriate for all children. Therefore, families should be educated about the impact of MHL and about available interventions so that informed decisions can be made.

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Minimal Hearing Loss: From a Failure-Based Approach to Evidence-Based Practice

Purpose

A representative sample of the literature on minimal hearing loss (MHL) was reviewed to provide evidence of challenges faced by children with MHL and to establish the need for evidence-based options for early intervention.

Method

Research articles published from 1950 to 2013 were searched in the Medline database using the keywords minimal hearing loss, unilateral hearing loss, and mild hearing loss. References cited in retrieved articles were also reviewed.

Results

In total, 69 articles contained relevant information about pediatric outcomes and/or intervention for unilateral hearing loss, 50 for mild hearing loss, and 6 for high-frequency hearing loss. Six challenges associated with MHL emerged, and 6 interventions were indicated. Evidence indicates that although some individuals may appear to have no observable speech-language or academic difficulties, others experience considerable difficulties. It also indicates that even though children with MHL may appear to catch up in some areas, difficulties in select domains continue into adulthood.

Conclusions

Evidence indicates significant risks associated with untreated MHL. Evidence also demonstrates the need for early intervention and identifies several appropriate intervention strategies; however, no single protocol is appropriate for all children. Therefore, families should be educated about the impact of MHL and about available interventions so that informed decisions can be made.

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Case Studies of Multilingual/Multicultural Asian Deaf Adults: Strategies for Success.

Related Articles

Case Studies of Multilingual/Multicultural Asian Deaf Adults: Strategies for Success.

Am Ann Deaf. 2016;161(1):67-88

Authors: Wang Q, Andrews J, Liu HT, Liu CJ

Abstract
Case studies of adult d/Deaf or Hard of Hearing Multilingual Learners (DMLs) are few, especially studies of DMLs who learn more than one sign language and read logographic and alphabetic scripts. To reduce this paucity, two descriptive case studies are presented. Written questionnaires, face-to-face interviews, and self-appraisals of language-use rubrics were used to explore (a) the language and literacy histories of two adult Asian DMLs who had learned multiple languages: Chinese (spoken/written), English (written), Chinese Sign Language, and American Sign Language; and (b) how each language was used in different cultural communities with diverse conversational partners. Home literacy environment, family support, visual access to languages, peer and sibling support, role models, encouragement, perseverance, and Deaf identity all played vital roles in the participants' academic success. The findings provide insights into the acquisition of multiple languages and bi-literacy through social communication and academic content.

PMID: 27156919 [PubMed - indexed for MEDLINE]

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Assessment and d/Deaf and Hard of Hearing Multilingual Learners: Considerations and Promising Practices.

Related Articles

Assessment and d/Deaf and Hard of Hearing Multilingual Learners: Considerations and Promising Practices.

Am Ann Deaf. 2016;161(1):56-66

Authors: Pizzo L, Chilvers A

Abstract
The authors address considerations and promising practices relating to assessment of d/Deaf and Hard of Hearing Multilingual Learners. DMLs' unique culture(s), language(s), and learning needs must be considered when assessments of this population are being planned, conducted, and interpreted. The authors address theory and research on (a) general considerations for the overarching assessment process, (b) specific assessment approaches used to assess DMLs, and (c) assessment of language proficiency for diverse language learners. In addition, basic recommendations for the assessment of DMLs are made, including increased availability of assessments in various languages, use of multiple sources of individual and family data, assessment of all languages, and incorporation of a strong assessment component (that includes nondiscrimination practices) into teacher preparation programs.

PMID: 27156918 [PubMed - indexed for MEDLINE]

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Early Intervention: A Multicultural Perspective on d/Deaf and Hard of Hearing Multilingual Learners.

Related Articles

Early Intervention: A Multicultural Perspective on d/Deaf and Hard of Hearing Multilingual Learners.

Am Ann Deaf. 2016;161(1):33-40

Authors: Sandy KB

Abstract
Today's pluralistic society is characterized by families from many linguistic and cultural backgrounds, including families with infants and toddlers who are deaf or hard of hearing (d/Dhh). Taking a multicultural perspective, the author examines family-centered early intervention (FCEI) and the transition to school services for children who are d/Dhh. Working with d/Dhh Multilingual Learners (DMLs) and their families presents a unique challenge to early intervention professionals: ensuring that families have adequate information and resources to make informed choices, particularly regarding communication. The author presents information and research related to (a) family and professional partnerships, (b) cultural contexts for early intervention,

PMID: 27156916 [PubMed - indexed for MEDLINE]

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d/Deaf and Hard of Hearing Multilingual Learners: The Development of Communication and Language.

Related Articles

d/Deaf and Hard of Hearing Multilingual Learners: The Development of Communication and Language.

Am Ann Deaf. 2016;161(1):17-32

Authors: Pizzo L

Abstract
The author examines the theory and research relevant to educating d/Deaf and Hard of Hearing Multilingual Learners (DMLs). There is minimal research on this population, yet a synthesis of related theory, research, and practice on spoken-language bilinguals can be used to add to the body of knowledge on these learners. Specifically, the author reports on three major areas: (a) population characteristics of DMLs, (b) theories relevant to understanding the language development of DMLs, and (c) considerations for programs in designing and implementing educational services for DMLs. In the interest of ensuring that children receive the foundation for linguistic success, aspects of linguistically responsive teaching (Lucas & Villegas, 2013) are addressed, with a focus on adopting an asset-based perspective on educating DMLs that honors all of a child's language, identity, and cultural memberships.

PMID: 27156915 [PubMed - indexed for MEDLINE]

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Effort and Displeasure in People Who Are Hard of Hearing.

Effort and Displeasure in People Who Are Hard of Hearing.

Ear Hear. 2016 Jul-Aug;37 Suppl 1:28S-34S

Authors: Matthen M

Abstract
Listening effort helps explain why people who are hard of hearing are prone to fatigue and social withdrawal. However, a one-factor model that cites only effort due to hardness of hearing is insufficient as there are many who lead happy lives despite their disability. This article explores other contributory factors, in particular motivational arousal and pleasure. The theory of rational motivational arousal predicts that some people forego listening comprehension because they believe it to be impossible and hence worth no effort at all. This is problematic. Why should the listening task be rated this way, given the availability of aids that reduce its difficulty? Two additional factors narrow the explanatory gap. First, we separate the listening task from the benefit derived as a consequence. The latter is temporally more distant, and is discounted as a result. The second factor is displeasure attributed to the listening task, which increases listening cost. Many who are hard of hearing enjoy social interaction. In such cases, the actual activity of listening is a benefit, not a cost. These people also reap the benefits of listening, but do not have to balance these against the displeasure of the task. It is suggested that if motivational harmony can be induced by training in somebody who is hard of hearing, then the obstacle to motivational arousal would be removed. This suggests a modified goal for health care professionals. Do not just teach those who are hard of hearing how to use hearing assistance devices. Teach them how to do so with pleasure and enjoyment.

PMID: 27355767 [PubMed - as supplied by publisher]

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Effort and Displeasure in People Who Are Hard of Hearing.

Effort and Displeasure in People Who Are Hard of Hearing.

Ear Hear. 2016 Jul-Aug;37 Suppl 1:28S-34S

Authors: Matthen M

Abstract
Listening effort helps explain why people who are hard of hearing are prone to fatigue and social withdrawal. However, a one-factor model that cites only effort due to hardness of hearing is insufficient as there are many who lead happy lives despite their disability. This article explores other contributory factors, in particular motivational arousal and pleasure. The theory of rational motivational arousal predicts that some people forego listening comprehension because they believe it to be impossible and hence worth no effort at all. This is problematic. Why should the listening task be rated this way, given the availability of aids that reduce its difficulty? Two additional factors narrow the explanatory gap. First, we separate the listening task from the benefit derived as a consequence. The latter is temporally more distant, and is discounted as a result. The second factor is displeasure attributed to the listening task, which increases listening cost. Many who are hard of hearing enjoy social interaction. In such cases, the actual activity of listening is a benefit, not a cost. These people also reap the benefits of listening, but do not have to balance these against the displeasure of the task. It is suggested that if motivational harmony can be induced by training in somebody who is hard of hearing, then the obstacle to motivational arousal would be removed. This suggests a modified goal for health care professionals. Do not just teach those who are hard of hearing how to use hearing assistance devices. Teach them how to do so with pleasure and enjoyment.

PMID: 27355767 [PubMed - as supplied by publisher]

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Subcortical correlates of auditory perceptual organization in humans

Publication date: Available online 29 June 2016
Source:Hearing Research
Author(s): Shimpei Yamagishi, Sho Otsuka, Shigeto Furukawa, Makio Kashino
To make sense of complex auditory scenes, the auditory system sequentially organizes auditory components into perceptual objects or streams. In the conventional view of this process, the cortex plays a major role in perceptual organization, and subcortical mechanisms merely provide the cortex with acoustical features. Here, we show that the neural activities of the brainstem are linked to perceptual organization, which alternates spontaneously for human listeners without any stimulus change. The stimulus used in the experiment was an unchanging sequence of repeated triplet tones, which can be interpreted as either one or two streams. Listeners were instructed to report the perceptual states whenever they experienced perceptual switching between one and two streams throughout the stimulus presentation. Simultaneously, we recorded event related potentials with scalp electrodes. We measured the frequency-following response (FFR), which is considered to originate from the brainstem. We also assessed thalamo-cortical activity through the middle-latency response (MLR). The results demonstrate that the FFR and MLR varied with the state of auditory stream perception. In addition, we found that the MLR change precedes the FFR change with perceptual switching from a one-stream to a two-stream percept. This suggests that there are top-down influences on brainstem activity from the thalamo-cortical pathway. These findings are consistent with the idea of a distributed, hierarchical neural network for perceptual organization and suggest that the network extends to the brainstem level.



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Correlation between word recognition score and intracochlear new bone and fibrous tissue after cochlear implantation in the human

Publication date: Available online 29 June 2016
Source:Hearing Research
Author(s): Takefumi Kamakura, Joseph B. Nadol
Cochlear implantation is an effective, established procedure for patients with profound deafness. Although implant electrodes have been considered as biocompatible prostheses, surgical insertion of the electrode induces various changes within the cochlea. Immediate changes include insertional trauma to the cochlea. Delayed changes include a tissue response consisting of inflammation, fibrosis and neo-osteogenesis induced by trauma and an immunologic reaction to a foreign body. The goal of this study was to evaluate the effect of these delayed changes on the word recognition scores achieved post-operatively. Seventeen temporal bones from patients who in life had undergone cochlear implantation were prepared for light microscopy. We digitally calculated the volume of fibrous tissue and new bone within the cochlea using Amira^® three-dimensional reconstruction software and assessed the correlations of various clinical and histologic factors. The postoperative CNC word score was positively correlated with total spiral ganglion cell count. Fibrous tissue and new bone were found within the cochlea of all seventeen specimens. The postoperative CNC word score was negatively correlated with the % volume of new bone within the scala tympani, scala media/vestibuli and the cochlea, but not with the % volume of fibrous tissue. The % volume of new bone in the scala media/vestibuli was positively correlated with the degree of intracochlear insertional trauma, especially trauma to the basilar membrane.Our results revealed that the % volume of new bone as well as residual total spiral ganglion cell count are important factors influencing post-implant hearing performance. New bone formation may be reduced by limiting insertional trauma and increasing the biocompatibility of the electrodes.



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Subcortical correlates of auditory perceptual organization in humans

Publication date: Available online 29 June 2016
Source:Hearing Research
Author(s): Shimpei Yamagishi, Sho Otsuka, Shigeto Furukawa, Makio Kashino
To make sense of complex auditory scenes, the auditory system sequentially organizes auditory components into perceptual objects or streams. In the conventional view of this process, the cortex plays a major role in perceptual organization, and subcortical mechanisms merely provide the cortex with acoustical features. Here, we show that the neural activities of the brainstem are linked to perceptual organization, which alternates spontaneously for human listeners without any stimulus change. The stimulus used in the experiment was an unchanging sequence of repeated triplet tones, which can be interpreted as either one or two streams. Listeners were instructed to report the perceptual states whenever they experienced perceptual switching between one and two streams throughout the stimulus presentation. Simultaneously, we recorded event related potentials with scalp electrodes. We measured the frequency-following response (FFR), which is considered to originate from the brainstem. We also assessed thalamo-cortical activity through the middle-latency response (MLR). The results demonstrate that the FFR and MLR varied with the state of auditory stream perception. In addition, we found that the MLR change precedes the FFR change with perceptual switching from a one-stream to a two-stream percept. This suggests that there are top-down influences on brainstem activity from the thalamo-cortical pathway. These findings are consistent with the idea of a distributed, hierarchical neural network for perceptual organization and suggest that the network extends to the brainstem level.



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Correlation between word recognition score and intracochlear new bone and fibrous tissue after cochlear implantation in the human

Publication date: Available online 29 June 2016
Source:Hearing Research
Author(s): Takefumi Kamakura, Joseph B. Nadol
Cochlear implantation is an effective, established procedure for patients with profound deafness. Although implant electrodes have been considered as biocompatible prostheses, surgical insertion of the electrode induces various changes within the cochlea. Immediate changes include insertional trauma to the cochlea. Delayed changes include a tissue response consisting of inflammation, fibrosis and neo-osteogenesis induced by trauma and an immunologic reaction to a foreign body. The goal of this study was to evaluate the effect of these delayed changes on the word recognition scores achieved post-operatively. Seventeen temporal bones from patients who in life had undergone cochlear implantation were prepared for light microscopy. We digitally calculated the volume of fibrous tissue and new bone within the cochlea using Amira^® three-dimensional reconstruction software and assessed the correlations of various clinical and histologic factors. The postoperative CNC word score was positively correlated with total spiral ganglion cell count. Fibrous tissue and new bone were found within the cochlea of all seventeen specimens. The postoperative CNC word score was negatively correlated with the % volume of new bone within the scala tympani, scala media/vestibuli and the cochlea, but not with the % volume of fibrous tissue. The % volume of new bone in the scala media/vestibuli was positively correlated with the degree of intracochlear insertional trauma, especially trauma to the basilar membrane.Our results revealed that the % volume of new bone as well as residual total spiral ganglion cell count are important factors influencing post-implant hearing performance. New bone formation may be reduced by limiting insertional trauma and increasing the biocompatibility of the electrodes.



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Subcortical correlates of auditory perceptual organization in humans

Publication date: Available online 29 June 2016
Source:Hearing Research
Author(s): Shimpei Yamagishi, Sho Otsuka, Shigeto Furukawa, Makio Kashino
To make sense of complex auditory scenes, the auditory system sequentially organizes auditory components into perceptual objects or streams. In the conventional view of this process, the cortex plays a major role in perceptual organization, and subcortical mechanisms merely provide the cortex with acoustical features. Here, we show that the neural activities of the brainstem are linked to perceptual organization, which alternates spontaneously for human listeners without any stimulus change. The stimulus used in the experiment was an unchanging sequence of repeated triplet tones, which can be interpreted as either one or two streams. Listeners were instructed to report the perceptual states whenever they experienced perceptual switching between one and two streams throughout the stimulus presentation. Simultaneously, we recorded event related potentials with scalp electrodes. We measured the frequency-following response (FFR), which is considered to originate from the brainstem. We also assessed thalamo-cortical activity through the middle-latency response (MLR). The results demonstrate that the FFR and MLR varied with the state of auditory stream perception. In addition, we found that the MLR change precedes the FFR change with perceptual switching from a one-stream to a two-stream percept. This suggests that there are top-down influences on brainstem activity from the thalamo-cortical pathway. These findings are consistent with the idea of a distributed, hierarchical neural network for perceptual organization and suggest that the network extends to the brainstem level.



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Correlation between word recognition score and intracochlear new bone and fibrous tissue after cochlear implantation in the human

Publication date: Available online 29 June 2016
Source:Hearing Research
Author(s): Takefumi Kamakura, Joseph B. Nadol
Cochlear implantation is an effective, established procedure for patients with profound deafness. Although implant electrodes have been considered as biocompatible prostheses, surgical insertion of the electrode induces various changes within the cochlea. Immediate changes include insertional trauma to the cochlea. Delayed changes include a tissue response consisting of inflammation, fibrosis and neo-osteogenesis induced by trauma and an immunologic reaction to a foreign body. The goal of this study was to evaluate the effect of these delayed changes on the word recognition scores achieved post-operatively. Seventeen temporal bones from patients who in life had undergone cochlear implantation were prepared for light microscopy. We digitally calculated the volume of fibrous tissue and new bone within the cochlea using Amira^® three-dimensional reconstruction software and assessed the correlations of various clinical and histologic factors. The postoperative CNC word score was positively correlated with total spiral ganglion cell count. Fibrous tissue and new bone were found within the cochlea of all seventeen specimens. The postoperative CNC word score was negatively correlated with the % volume of new bone within the scala tympani, scala media/vestibuli and the cochlea, but not with the % volume of fibrous tissue. The % volume of new bone in the scala media/vestibuli was positively correlated with the degree of intracochlear insertional trauma, especially trauma to the basilar membrane.Our results revealed that the % volume of new bone as well as residual total spiral ganglion cell count are important factors influencing post-implant hearing performance. New bone formation may be reduced by limiting insertional trauma and increasing the biocompatibility of the electrodes.



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