Pick Topic
Review Topic
List Experts
Examine Expert
Save Expert
  Site Guide ··   
Hearing Disorders: HELP
Articles by Hiroshi Yamazaki
Based on 10 articles published since 2010
(Why 10 articles?)
||||

Between 2010 and 2020, Hiroshi Yamazaki wrote the following 10 articles about Hearing Disorders.
 
+ Citations + Abstracts
1 Article First Implant-Induced Changes in Rostral Brainstem Impair Second Implant Outcomes in Sequential Bilateral Cochlear Implant Children With Long Inter-Implant Delay. 2019

Kishimoto, Ippei / Yamazaki, Hiroshi / Naito, Yasushi / Moroto, Saburo / Yamazaki, Tomoko. ·Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto. · Department of Otolaryngology, Head and Neck Surgery, Osaka Red Cross Hospital, Tennouji-ku, Osaka. · Department of Otolaryngology, Kobe City Medical Center General Hospital, Chuo-ku, Kobe, Japan. ·Otol Neurotol · Pubmed #30870357.

ABSTRACT: HYPOTHESIS: Long-term unilateral use of a cochlear implant (CI) induces abnormal maturation of the rostral brainstem innervating the contralateral ear. BACKGROUND: In sequential bilateral CI children with long inter-implant delay, both sides of auditory cortices were dominantly activated by the first CI, but mechanisms of this abnormal development of the auditory system remain unclear. METHODS: Fifteen sequential bilateral CI children with long delay (mean ± SD, 28.7 ± 12.1 mo) underwent electrically evoked auditory brainstem response (EABR) testing using each of the first and second CI (CI1 and CI2, respectively), immediately after the second implantation. CI1 and CI2 were implanted at age of 23.7 ± 9.6 and 53.1 ± 12.1 months (mean ± SD), respectively. Apical-to-basal difference in electrically evoked interwave III-V latencies (eIII-eV slope) which decreases with implant use was compared between the CI1 and CI2 sides. Their speech perception scores were evaluated 3 years after the second implantation. RESULTS: eIII-eV slopes evoked by the CI2 showed less mature pattern than those by the CI1. This CI2 versus CI1 difference in eIII-eV slopes, however, reduced as the inter-implant delay was prolonged, suggesting CI1-induced maturation of the rostral brainstem innervating the second ear before the second implantation. The smaller CI2 versus CI1 difference in eIII-eV slopes at the second implantation was correlated to poorer outcomes using the CI2 than the CI1. CONCLUSIONS: In this population, long-term unilateral CI use induced re-organization of the rostral brainstem innervating the second ear, which affected hearing outcomes using the CI2. Evaluation of eIII-eV slopes at the second implantation may be useful to predict hearing outcomes with CI2.

2 Article Cortical Processing of Level Cues for Spatial Hearing is Impaired in Children with Prelingual Deafness Despite Early Bilateral Access to Sound. 2018

Easwar, Vijayalakshmi / Yamazaki, Hiroshi / Deighton, Michael / Papsin, Blake / Gordon, Karen. ·Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Room 6D08, 555 University Avenue, Toronto, ON, M5G 1X8, Canada. veaswar@nca.uwo.ca. · Collaborative Program in Neuroscience, University of Toronto, Toronto, Canada. veaswar@nca.uwo.ca. · Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Room 6D08, 555 University Avenue, Toronto, ON, M5G 1X8, Canada. · Department of Otolaryngology, University of Toronto, Toronto, Canada. · Department of Otolaryngology, The Hospital for Sick Children, Toronto, Canada. ·Brain Topogr · Pubmed #29119311.

ABSTRACT: Bilateral cochlear implantation aims to restore binaural hearing, important for spatial hearing, to children who are deaf. Improvements over unilateral implant use are attributed largely to the detection of interaural level differences (ILDs) but emerging evidence of impaired sound localization and binaural fusion suggest that these binaural cues are abnormally coded by the auditory system. We used multichannel electroencephalography (EEG) to assess cortical responses to ILDs in two groups: 13 children who received early bilateral cochlear implants (CIs) simultaneously, known to protect the developing auditory cortices from unilaterally driven reorganization, and 15 age matched peers with normal hearing. EEG source analyses indicated a dominance of right auditory cortex in both groups. Expected reductions in activity to ipsilaterally weighted ILDs were evident in the right hemisphere of children with normal hearing. By contrast, cortical activity in children with CIs showed: (1) limited ILD sensitivity in either cortical hemisphere, (2) limited correlation with reliable behavioral right-left lateralization of ILDs (in 10/12 CI users), and (3) deficits in parieto-occipital areas and the cerebellum. Thus, expected cortical ILD coding develops with normal hearing but is affected by developmental deafness despite early and simultaneous bilateral implantation. Findings suggest that impoverished fidelity of ILDs in independently functioning CIs may be impeding development of cortical ILD sensitivity in children who are deaf but do not altogether limit benefits of listening with bilateral CIs. Future efforts to provide consistent/accurate ILDs through auditory prostheses including CIs could improve binaural hearing for children with hearing loss.

3 Article Simultaneous bilateral cochlear implants: Developmental advances do not yet achieve normal cortical processing. 2017

Easwar, Vijayalakshmi / Yamazaki, Hiroshi / Deighton, Michael / Papsin, Blake / Gordon, Karen. ·Archie's Cochlear Implant Laboratory The Hospital for Sick Children Toronto ON Canada. · Collaborative Program in Neuroscience The University of Toronto Toronto ON Canada. · Otolaryngology The University of Toronto Toronto ON Canada. · Otolaryngology The Hospital for Sick Children Toronto ON Canada. ·Brain Behav · Pubmed #28413698.

ABSTRACT: BACKGROUND: Simultaneous bilateral cochlear implantation promotes symmetric development of bilateral auditory pathways but binaural hearing remains abnormal. To evaluate whether bilateral cortical processing remains impaired in such children, cortical activity to unilateral and bilateral stimuli was assessed in a unique cohort of 16 children who received bilateral cochlear implants (CIs) simultaneously at 1.97 ± 0.86 years of age and had ~4 years of CI experience, providing the first opportunity to assess electrically driven cortical development in the absence of reorganized asymmetries from sequential implantation. METHODS: Cortical activity to unilateral and bilateral stimuli was measured using multichannel electro-encephalography. Cortical processing in children with bilateral CIs was compared with click-elicited activity in 13 normal hearing children matched for time-in-sound. Source activity was localized using the Time Restricted, Artefact and Coherence source Suppression (TRACS) beamformer method. RESULTS: Consistent with dominant crossed auditory pathways, normal P1 activity (~100 ms) was weaker to ipsilateral stimuli relative to contralateral and bilateral stimuli and both auditory cortices preferentially responded to the contralateral ear. Right hemisphere dominance was evident overall. Children with bilateral CIs maintained the expected right dominance but differences from normal included: (i) minimal changes between ipsilateral, contralateral and bilateral stimuli, (ii) weaker than normal contralateral stimulus preference, (iii) symmetric activity to bilateral stimuli, and (iv) increased occipital lobe recruitment during bilateral relative to unilateral stimulation. Between-group contrasts demonstrated lower than normal activity in the inferior parieto-occipital lobe (suggesting deficits in sensory integration) and greater than normal left frontal lobe activity (suggesting increased attention), even during passive listening. CONCLUSIONS: Together, findings suggest that early simultaneous bilateral cochlear implantation promotes normal-like auditory symmetry but that abnormalities in cortical processing consequent to deafness and/or electrical stimulation through two independent speech processors persist.

4 Article Cortical Representation of Interaural Time Difference Is Impaired by Deafness in Development: Evidence from Children with Early Long-term Access to Sound through Bilateral Cochlear Implants Provided Simultaneously. 2017

Easwar, Vijayalakshmi / Yamazaki, Hiroshi / Deighton, Michael / Papsin, Blake / Gordon, Karen. ·Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada, v.easwar@utoronto.ca. · Collaborative Program in Neuroscience, University of Toronto, Toronto, Ontario M5S 1A8, Canada. · Archie's Cochlear Implant Laboratory, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada. · Department of Otolaryngology, University of Toronto, Toronto, Ontario M5G 2N2, Canada, and. · Department of Otolaryngology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada. ·J Neurosci · Pubmed #28123078.

ABSTRACT: Accurate use of interaural time differences (ITDs) for spatial hearing may require access to bilateral auditory input during sensitive periods in human development. Providing bilateral cochlear implants (CIs) simultaneously promotes symmetrical development of bilateral auditory pathways but does not support normal ITD sensitivity. Thus, although binaural interactions are established by bilateral CIs in the auditory brainstem, potential deficits in cortical processing of ITDs remain. Cortical ITD processing in children with simultaneous bilateral CIs and normal hearing with similar time-in-sound was explored in the present study. Cortical activity evoked by bilateral stimuli with varying ITDs (0, ±0.4, ±1 ms) was recorded using multichannel electroencephalography. Source analyses indicated dominant activity in the right auditory cortex in both groups but limited ITD processing in children with bilateral CIs. In normal-hearing children, adult-like processing patterns were found underlying the immature P1 (∼100 ms) response peak with reduced activity in the auditory cortex ipsilateral to the leading ITD. Further, the left cortex showed a stronger preference than the right cortex for stimuli leading from the contralateral hemifield. By contrast, children with CIs demonstrated reduced ITD-related changes in both auditory cortices. Decreased parieto-occipital activity, possibly involved in spatial processing, was also revealed in children with CIs. Thus, simultaneous bilateral implantation in young children maintains right cortical dominance during binaural processing but does not fully overcome effects of deafness using present CI devices. Protection of bilateral pathways through simultaneous implantation might be capitalized for ITD processing with signal processing advances, which more consistently represent binaural timing cues.

5 Article Audio-visual integration during speech perception in prelingually deafened Japanese children revealed by the McGurk effect. 2015

Tona, Risa / Naito, Yasushi / Moroto, Saburo / Yamamoto, Rinko / Fujiwara, Keizo / Yamazaki, Hiroshi / Shinohara, Shogo / Kikuchi, Masahiro. ·Department of Otolaryngology, Kobe City Medical Center General Hospital, Kobe, Japan; Department of Otolaryngology, Institute of Biomedical Research and Innovation, Kobe, Japan; Department of Otolaryngology, Kyoto University Graduate School of Medicine, Kyoto, Japan. · Department of Otolaryngology, Kobe City Medical Center General Hospital, Kobe, Japan; Department of Otolaryngology, Institute of Biomedical Research and Innovation, Kobe, Japan. Electronic address: naito@kcho.jp. · Department of Otolaryngology, Kobe City Medical Center General Hospital, Kobe, Japan; Department of Otolaryngology, Institute of Biomedical Research and Innovation, Kobe, Japan. · Department of Otolaryngology, Kobe City Medical Center General Hospital, Kobe, Japan. · Department of Otolaryngology, Kobe City Medical Center General Hospital, Kobe, Japan; Department of Otolaryngology, Kyoto University Graduate School of Medicine, Kyoto, Japan. ·Int J Pediatr Otorhinolaryngol · Pubmed #26455920.

ABSTRACT: OBJECTIVE: To investigate the McGurk effect in profoundly deafened Japanese children with cochlear implants (CI) and in normal-hearing children. This was done to identify how children with profound deafness using CI established audiovisual integration during the speech acquisition period. METHODS: Twenty-four prelingually deafened children with CI and 12 age-matched normal-hearing children participated in this study. Responses to audiovisual stimuli were compared between deafened and normal-hearing controls. Additionally, responses of the children with CI younger than 6 years of age were compared with those of the children with CI at least 6 years of age at the time of the test. RESULTS: Responses to stimuli combining auditory labials and visual non-labials were significantly different between deafened children with CI and normal-hearing controls (p<0.05). Additionally, the McGurk effect tended to be more induced in deafened children older than 6 years of age than in their younger counterparts. CONCLUSIONS: The McGurk effect was more significantly induced in prelingually deafened Japanese children with CI than in normal-hearing, age-matched Japanese children. Despite having good speech-perception skills and auditory input through their CI, from early childhood, deafened children may use more visual information in speech perception than normal-hearing children. As children using CI need to communicate based on insufficient speech signals coded by CI, additional activities of higher-order brain function may be necessary to compensate for the incomplete auditory input. This study provided information on the influence of deafness on the development of audiovisual integration related to speech, which could contribute to our further understanding of the strategies used in spoken language communication by prelingually deafened children.

6 Article SLC26A4 p.Thr410Met homozygous mutation in a patient with a cystic cochlea and an enlarged vestibular aqueduct showing characteristic features of incomplete partition type I and II. 2014

Yamazaki, Hiroshi / Naito, Yasushi / Moroto, Saburo / Tamaya, Rinko / Yamazaki, Tomoko / Fujiwara, Keizo / Ito, Juichi. ·Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. Electronic address: h_yamazaki@ent.kuhp.kyoto-u.ac.jp. · Department of Otolaryngology, Kobe City Medical Center General Hospital, Kobe, Japan. · Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. ·Int J Pediatr Otorhinolaryngol · Pubmed #25468468.

ABSTRACT: Mutations of SLC26A4 are associated with incomplete partition type II (IP-II) and isolated enlargement of the vestibular aqueduct (EVA). We experienced a congenitally deaf 6-year-old boy with a rare p.Thr410Met homozygous mutation in SLC26A4 who underwent bilateral cochlear implantation. He had bilateral inner ear malformation, in which the dilated vestibule and EVA were identical to those in IP-II, but the cochlea lacking a bony modiolus resembled that in incomplete partition type I. These results suggest that homozygous mutations in SLC26A4 are always associated with EVA, while the severity of cochlear malformation may vary depending on the type of SLC26A4 mutation.

7 Article Comprehensive analysis of cochlear implant failure: usefulness of clinical symptom-based algorithm combined with in situ integrity testing. 2014

Yamazaki, Hiroshi / O'Leary, Stephen / Moran, Michelle / Briggs, Robert. ·*Department of Otolaryngology, Kobe City Medical Center General Hospital; †Institute of Biomedical Research and Innovation, Kobe, Hyogo, Japan; ‡The Royal Victorian Eye and Ear Hospital; ∥Department of Audiology and Speech Pathology, University of Melbourne; ¶The HEARing Co-operative Research Centre; and §The Department of Otolaryngology, University of Melbourne, Melbourne, Victoria. ·Otol Neurotol · Pubmed #24622015.

ABSTRACT: OBJECTIVE: Accurate diagnosis of cochlear implant failures is important for management; however, appropriate strategies to assess possible device failures are not always clear. The purpose of this study is to understand correlation between causes of device failure and the presenting clinical symptoms as well as results of in situ integrity testing and to propose effective strategies for diagnosis of device failure. STUDY DESIGN: Retrospective case review. SETTING: Cochlear implant center at a tertiary referral hospital. PATIENTS: Twenty-seven cases with suspected device failure of Cochlear Nucleus systems (excluding CI512 failures) on the basis of deterioration in auditory perception from January 2000 to September 2012 in the Melbourne cochlear implant clinic. MAIN OUTCOME MEASURES: Clinical presentations and types of abnormalities on in situ integrity testing were compared with modes of device failure detected by returned device analysis. RESULTS: Sudden deterioration in auditory perception was always observed in cases with "critical damage": either fracture of the integrated circuit or most or all of the electrode wires. Subacute or gradually progressive deterioration in auditory perception was significantly associated with a more limited number of broken electrode wires. Cochlear implant mediated auditory and nonauditory symptoms were significantly associated with an insulation problem. An algorithm based on the time course of deterioration in auditory perception and cochlear implant-mediated auditory and nonauditory symptoms was developed on the basis of these retrospective analyses, to help predict the mode of device failure. In situ integrity testing, which included close monitoring of device function in routine programming sessions as well as repeating the manufacturer's integrity test battery, was sensitive enough to detect malfunction in all suspected device failures, and each mode of device failure showed a characteristic abnormality on in situ integrity testing. CONCLUSION: Our clinical manifestation-based algorithm combined with in situ integrity testing may be useful for accurate diagnosis and appropriate management of device failure. Close monitoring of device function in routine programming sessions as well as repeating the manufacturer's integrity test battery is important if the initial in situ integrity testing is inconclusive because objective evidence of failure in the implanted device is essential to recommend explantation/reimplantation.

8 Article Clinical features of rapidly progressive bilateral sensorineural hearing loss. 2014

Kishimoto, Ippei / Yamazaki, Hiroshi / Naito, Yasushi / Shinohara, Shogo / Fujiwara, Keizo / Kikuchi, Masahiro / Kanazawa, Yuji / Tona, Risa / Harada, Hiroyuki. ·Department of Otolaryngology, Kobe City Medical Center General Hospital , Kobe. ·Acta Otolaryngol · Pubmed #24256048.

ABSTRACT: CONCLUSION: Rapidly progressive bilateral sensorineural hearing loss (SNHL) often develops as a symptom of intracranial diseases or systemic vasculitis. For early diagnosis and treatment of these potentially fatal diseases, a history of hearing deterioration within 2 months and associated symptoms may be important. OBJECTIVES: To reveal clinical features and causative diseases for rapidly progressive bilateral SNHL. METHODS: The inclusion criterion was patients with bilateral progressive SNHL, who had experienced difficulty in daily conversation within 4 days to 1 year after the onset of hearing loss awareness. This study was a retrospective evaluation of 12 patients with rapidly progressive bilateral SNHL who visited our hospital between 2007 and 2011. RESULTS: The causative disease for hearing loss was identified in 11 of 12 patients; intracranial lesions including nonbacterial meningitis, meningeal metastasis of lymphoma, and superficial siderosis in 4 patients, systemic vasculitis in 2, auditory neuropathy spectrum disorder in 1, and an isolated inner ear disorder in 4. Relatively rapid hearing deterioration within 2 months showed a significant association in six patients with an intracranial lesion or systemic vasculitis. Moreover, all these six patients complained of dizziness and/or non-cochleovestibular symptoms such as fever, headache, and/or altered mental state in addition to hearing loss.

9 Article Cochlear implantation in children with congenital cytomegalovirus infection accompanied by psycho-neurological disorders. 2012

Yamazaki, Hiroshi / Yamamoto, Rinko / Moroto, Saburo / Yamazaki, Tomoko / Fujiwara, Keizo / Nakai, Masako / Ito, Juichi / Naito, Yasushi. ·Department of Otolaryngology, Kobe City Medical Center General Hospital, Japan. ·Acta Otolaryngol · Pubmed #22443855.

ABSTRACT: CONCLUSION: Cochlear implantation was effective for deaf children with congenital cytomegalovirus (CMV) infection, but their cochlear implant (CI) outcomes were often impaired, depending on the types of CMV-associated psycho-neurological disorders. Evaluation of cognitive development and autistic tendency of implantees might be useful to predict their CI outcomes. OBJECTIVES: To reveal the influence of CMV-associated psycho-neurological disorders on CI outcomes. METHODS: This was a retrospective evaluation of 11 implantees with congenital CMV infection (CMV-CIs) and 14 implantees with autosomal recessive hearing loss (genetic-CIs). RESULTS: Nine of 11 CMV-CIs suffered from psycho-neurological disorders; one from attention deficit hyperactivity disorder, two from pervasive developmental disorder, and six from mental retardation. Aided hearing thresholds with CIs in the two groups did not differ, but two autistic and two mentally retarded CMV-CIs showed significantly low scores in speech discrimination tests. Language-Social (L-S) developmental quotients (DQs) evaluated by the Kyoto Scale of Psychological development were improved after the implantation in both groups, but the postoperative increase of L-S DQs was significantly smaller in the CMV-CIs than that of genetic-CIs. Interestingly, the postoperative L-S and Cognitive-Adaptive (C-A) DQs showed statistically significant correlation in all cases except for two autistic CMV-CIs whose L-S DQs were much lower than those expected from their C-A DQs.

10 Article Reversible cochlear disorders with normal vestibular functions in three cases with Wegener's granulomatosis. 2012

Yamazaki, Hiroshi / Fujiwara, Keizo / Shinohara, Shogo / Kikuchi, Masahiro / Kanazawa, Yuji / Kurihara, Risa / Kishimoto, Ippei / Naito, Yasushi. ·Department of Otolaryngology, Kobe City Medical Center General Hospital, Kobe, Japan. yamazaki@kcho.jp ·Auris Nasus Larynx · Pubmed #21601391.

ABSTRACT: Patients with Wegener's granulomatosis (WG) often suffer from hearing loss, but its precise mechanisms have not been well understood. We experienced 3 WG cases whose initial symptoms were bilateral progressive mixed (both conductive and sensorineural) hearing loss, followed by systemic symptoms one year later. They were diagnosed as WG based on positive serology of anti-neutrophil cytoplasmic antibodies (ANCAs) and pathologic findings of affected lesions in addition to systemic symptoms. Although they were different in the type of ANCAs and systemic lesions, all showed considerably reversible cochlear disorders with normal vestibular functions. Moreover, their initial otologic manifestations shared same characteristic features, (1) thick ear drums with pulsatile serous intratympanic effusion, (2) poor speech discrimination ability, and (3) steroid-dependent changes of hearing levels (HLs). They exhibited no significant vestibular abnormalities in chair vestibule-ocular reflex (VOR) testing and cold air caloric tests even when they had severe hearing loss. On the basis of these results, we hypothesized that vasculitis of stria vascularis which generates endocochlear potential might cause these reversible cochlear-specific dysfunctions.