[Evaluation of the outcomes of cochlear implant in children with auditory neuropathy].

Objective: To investigate the auditory and speech abilities of children with congenital auditory neuropathy (AN) after cochlear implant (CI), and to analyze the role of genetic testing in predicting the postoperative outcomes of CI in AN patients. Methods: Fourteen children diagnosed with AN by audiological battery test and underwent CI surgery in Xijing Hospital of the Air Force Medical University from 2002 to 2021 were included in this study (9 males and 5 females), with an implantation age of (3.1±1.7) years (mean±standard deviation, the same as follows). The preoperative audiological results and deafness gene results were analyzed. Another 52 children with ordinary sensorineural hearing loss (SNHL) were selected as the control group (30 males and 22 females), with an implantation age of (2.2±0.9) years. The demographic factors such as age and gender were matched with those of the AN group. The modified Category Auditory Performance (CAP-Ⅱ) and Speech Intelligence Rate (SIR) were used to evaluate the development of postoperative auditory and speech abilities in two groups. The Mandarin Speech Test System was used to test the speech recognition rate of monosyllabic and disyllabic words and sentences. Matlab 2022 software was used to analyze the data. Results: The results of gene in 14 children with AN showed that 6 cases had OTOF gene mutations, 2 cases (siblings) were confirmed to have TNN gene mutations through whole exome sequencing, and the remaining 6 cases were not find any clear pathogenic gene mutations. All subjects underwent CI surgery with electrodes implanted into the cochlea smoothly, and there were no postoperative complications. After surgery, all AN children had improved auditory and speech abilities, but only 64% (9/14) of AN children with CI had auditory ability scores comparable to the control group of SNHL children (including 2 children with TNN gene mutations), and 36% (5/14) of AN children had lower scores than the control group of SNHL children.The average speech recognition rate of two children with TNN gene mutations was 86.5%, and of two children with OTOF gene mutations was 83.2%. Conclusions: AN children achieved varying degrees of auditory and speech abilities after CI, but the postoperative effects varied greatly. Some children achieved similar results as ordinary SNHL children, but there were still some children whose effects were worse than those of ordinary SNHL children. The postoperative efficacy of CI in two children with AN caused by TNN pathogenic genes were comparable to that of ordinary SNHL in children. Genetic testing had certain reference value for predicting the postoperative effect of CI in AN children.

Cochlear implantation in children with auditory neuropathy spectrum disorder: an updated systematic review.

BACKGROUND: The goal of managing auditory neuropathy spectrum disorder (ANSD) is to restore the children's ability to discriminate auditory information. Children who are not making sufficient progress in speech comprehension, and speech and language development after receiving adequate auditory re/habilitation and/or acoustic amplification may be candidates for cochlear implantation (CI). Despite the growing number of published literature on CI outcomes in children with ANSD, the current evidence is primarily based on case reports or retrospective chart reviews some of which had a limited number of children. In addition, the outcomes of CI seem to vary between children with ANSD. Thus, compelling evidence is lacking. This updated systematic review evaluated the speech perception, language, and speech intelligibility outcomes of children with ANSD post-CI. METHODS: An online bibliographic search was conducted in PubMed, Scopus, Web of Science, and CENTRAL databases. We included both interventional and observational studies that assessed the outcomes of the CI in  children with ANSD. RESULTS: Thirty-three studies were included in this systematic review. Several tests were used to assess speech perception following CI in children with ANSD. The findings of this study revealed that  children with ANSD had mean Categories of Auditory Performance scores ranging from 4.3 to 7 post-operatively, this result was better than the pre-operative scores which ranged between 0.4 to 2.5. Likewise, the Infant-Toddler Meaningful Auditory Integration Scale, Phonetically Balanced Kindergarten, and multisyllabic lexical neighborhood test showed clinically relevant improvement after CI. The same findings were reported for language and speech intelligibility scores. One study investigated the quality of life/children satisfaction after CI and showed overall good satisfaction with the outcomes. CONCLUSIONS: The present systematic review suggests that CI is a feasible and effective hearing  rehabilitation modality for children with ANSD. REGISTRATION AND PROTOCOL: PROSPERO ID: CRD42021279140.

Results of cochlear implant surgery in patients with auditory neuropathy.

OBJECTIVES: The primary aim of this study was to analyze the benefit of cochlear implants for patients with auditory neuropathy. The secondary aim was to identify risk factors for auditory neuropathy. MATERIALS AND METHODS: Patients with cochlear implants (CIs) who were educated in hearing rehabilitation schools were included in the study. A total of 175 children were operated on for cochlear implantation between August 2019 and August 2021 in the department of otorhinolaryngology at different centers in Turkey, and while 16 (9.1%) of those patients had auditory neuropathy spectrum disorder (ANSD), 159 (90.9%) had sensorineural hearing loss (SNHL). Differences in auditory perception between the two groups were examined. Auditory perception tests were applied for these patients 6 months after CI surgery. The auditory perception performances of the patients were evaluated with the Evaluation of Auditory Responses to Speech (EARS) battery, including the Littlears, Lip, Bis4, Bis12, Cap, Sir, Mtp-3, Mtp-6, Mtp-12, Matrix A1, and Gasp tests. RESULTS: All patients had profound bilateral SNHL. Four auditory perception tests (Littlears, Bis-12, Sir, Matrix A1) showed similar results between patients with ANSD and SNHL, but seven auditory perception tests (Lip, Bis-4, Cap, Mtp-3, Mtp-6, Mtp-12, Gasp) showed significantly higher results among patients with SNHL. Hyperbilirubinemia, prematurity, consanguineous marriage, and family history of hearing loss were found to be common among patients with ANSD. CONCLUSIONS: ANSD patients who do not benefit from hearing aids benefit from CI surgery.

Cochlear implantation in patient with Charcot-Marie-Tooth disease.

Two patients with auditory neuropathy spectrum disorder (ANSD) considered to be associated with Charcot-Marie-Tooth (CMT) are reported. In case 1, a 23-year-old man presented with progressive bilateral sensorineural hearing loss (SNHL) from 10 years of age and was diagnosed with ANSD. He was later diagnosed with CMT by neurological testing. In case 2, a 16-year-old girl, the younger sister of the patient in case 1, presented with progressive SNHL with similar auditory findings since 6 years of age as those of her brother. Both cases underwent bilateral cochlear implantation. In case 1, the maximum discrimination score improved to 45% 24 months after the first side of cochlear implantation from 5% before the surgery. In case 2, the score was 5% 10 months after cochlear implant (CI) surgery from 0% before the surgery. CI treatment for CMT patients has been considered difficult because of both failure in synchronization of nerve conduction due to demyelination and axonal failure of the auditory nerve. Though slower progress compared to the average subset of patients receiving CI was seen, significant improvement was gradually observed in the present patients after bilateral cochlear implantations. CI is thus a viable option for rehabilitation of SNHL in CMT patients.

Taurine enhances mouse cochlear neural stem cell transplantation via the cochlear lateral wall for replacement of degenerated spiral ganglion neurons via sonic hedgehog signaling pathway.

The aim of this paper is to investigate the potential beneficial effects of taurine in cochlear neural stem cell (NSC) transplantation and elucidate the underlying molecular mechanism. The NSC cells were isolated from neonatal Balb/c mice and an auditory neuropathy gerbil model was established by microinjection of ouabain. The spiral ganglion neurons (SGN) were characterized with immunofluorescence stained with Tuj1 antibody. Cell proliferation was determined by BrdU incorporation assay and the morphologic index was measured under the light microscope. The relative protein level was determined by immunoblotting. The hearing of the animal model was scored by click- and tone burst-evoked auditory brainstem response (ABR). Here we consolidated our previous finding that taurine stimulated SGN density and the proliferation index, which were completely abolished by Shh inhibitor, cyclopamine. Transplantation of cochlear NSCs combined with taurine significantly improved ouabain-induced auditory neuropathy in gerbils. In addition, cyclopamine antagonized taurine's effect on glutamatergic and GABAergic neuron population via suppression of VGLUT1 and GAT1 expression. Mechanistically, taurine evidently activated the Sonic HedgeHog pathway and upregulated Shh, Ptc-1, Smo and Gli-1 proteins, which were specifically blockaded by cyclopamine. Here, for the first time demonstrated we that co-administration with taurine significantly improved NSC transplantation and the Shh pathway was identified in this beneficial effect.

The use of animal models to study cell transplantation in neuropathic hearing loss.

Auditory neuropathy (AN) is a form of sensorineural deafness specifically affecting the conduction of the nerve impulse from the cochlear hair cells to the auditory centres of the brain. As such, the condition is a potential clinical target for 'cell replacement therapy', in which a functioning auditory nerve is regenerated by transplanting an appropriated neural progenitor. In this review, we survey the current literature and examine possible experimental models for this condition, with particular reference to their compatibility as suitable hosts for transplantation. The use of exogenous neurotoxic agents such as ouabain or ß-bungarotoxin is discussed, as are ageing and noise-induced synaptopathy models. Lesioning of the nerve by mechanical damage during surgery and the neuropathy resulting from infectious diseases may be very relevant clinically, and we discuss whether there are good models for these situations. We also address genetic models for AN, examining whether the phenotypes truly model the clinical situation in their human counterpart syndromes - we use the example of the hyperbilirubinaemic Gunn rat as a particular instance in this regard.

Transplantation of human limbus-derived mesenchymal stromal cells via occipital approach improves hearing in animal auditory neuropathy.

OBJECTIVE: To develop a surgical approach for cell transplantation into mouse cochlear nerves via an intracranial route and investigate whether transplantation of human limbus-derived mesenchymal stromal cells (HL-MSCs) can improve hearing in this model of auditory neuropathy. METHODS: We used 8-week-old CBA/CaJ male mice and created ouabain-induced auditory neuropathy. The surgical approach passed through the cerebellum to reveal the superior semicircular canal and brainstem, allowing access to the auditory nerve. Then HL-MSCs were injected around the cochlear nerve trunk using a micropipette driven by a micropump. Hearing thresholds in the mice were determined by auditory brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs). RESULTS: We produced ouabain-induced neuropathy in mice with an elevated hearing threshold but normal DPOAE. Using immunohistological staining, we detected HL-MSCs were localized in the cochlear nerve trunk 2 days after cell transplantation via this occipital approach. More spiral ganglion neurons were detected in ouabain-treated cochleae 3 months after HL-MSCs transplantation compared to those without HL-MSCs transplantation. The ABR showed significant hearing improvement 3 months after HL-MSCs transplantation. CONCLUSIONS: We successfully established a mouse model for cell transplantation into the intracranial cochlear nerve trunk and showed that HL-MSCs potentially can be applied as cell therapy to treat sensorineural hearing loss.

Targeted next generation sequencing reveals OTOF mutations in auditory neuropathy spectrum disorder.

OBJECTIVE: To study the genetic etiology of auditory neuropathy spectrum disorder (ANSD) in a Chinese family and perform a literature review of OTOF mutations and cochlear implantation (CI). METHODS: Sequential targeted next generation sequencing (NGS) and CI was performed for the proband. Further, 50 DNA samples from unrelated families with nonsyndromic deafness were examined for frequency determination. The impact of OTOF mutations on hearing recovery after CI was assessed through the literature survey. RESULTS: In the proband, the targeted NGS panel revealed five suspected variants in four genes (OTOF, EYA4, PCDH15, and GIPC3), of which two mutations-c.5098G > C (p.Glu1700Gln) and c.1702C > T (p.Arg568Trp)-in the OTOF gene were found to be correlated with ANSD. The c.5098G > C allele was identified in only one child from the 50 unrelated participants. The proband's hearing and speech abilities were restored 2 years after the surgery. Most ANSD patients (90.9%; 30/33) with OTOF mutations have acceptable surgical outcomes, as indicated by existing reports. CONCLUSIONS: Our results support the feasibility of CI for patients with ANSD and OTOF mutations, and this hypothesis was supported by the review of existing data. A larger number of cases studies is required to determine possible modifies on the prognosis of surgery.

Cochlear implantation in children with auditory neuropathy spectrum disorder: A multicenter study on auditory performance and speech production outcomes.

OBJECTIVES: To evaluate the auditory performance and speech production outcome in children with auditory neuropathy spectrum disorder (ANSD). The effect of age on the outcomes of the surgery at the time of implantation was also evaluated. METHODS: Cochlear implantation was performed in 136 children with bilateral severe-to- profound hearing loss due to ANSD, at four tertiary academic centers. The patients were divided into two groups based on the age at the time of implantation; Group I: Children ≤24 months, and Group II: subjects >24 months. The categories of auditory performance (CAP) and speech intelligibility rating (SIR) scores were evaluated after the first and second years of implantation. The differences between the CAP and SIR scores in the two groups were assessed. RESULTS: The median CAP scores improved significantly after the cochlear implantation in all the patients (p value < 0.001). The improvement in the CAP scores during the first year in Group II was greater than Group I (p value: 0.007), but the improvement in CAP scores tended to be significantly higher in patients who were implanted at ≤24 months (p value < 0.001). There was no significant difference between two groups in SIR scores at first-year and second-year follow-ups. The evaluation of the SIR improvement revealed significantly higher values for Group I during the second-year follow-up (p value: 0.003). CONCLUSION: The auditory performance and speech production skills of the children with ANSD improved significantly after cochlear implantation, and this improvement was affected by age at the time of implantation.

Percepção de fala em deficientes auditivos pré-linguais com desordem do espectro da neuropatia auditiva usuários de aparelho auditivo de amplificação sonora / Speech perception in users of hearing aid with auditory neuropathy spectrum disorder

RESUMO Objetivo: Analisar a percepção de fala em crianças portadoras de deficiência auditiva pré-lingual com desordem do espectro da neuropatia auditiva (DENA) usuárias de aparelho de amplificação sonora individual (AASI) bilateral. Métodos: Trata-se de um estudo descritivo e exploratório realizado no Centro de Pesquisas Audiológicas da Sessão de Implante Coclear do Hospital de Reabilitação de Anomalias Craniofaciais (HRAC/USP). Foram avaliadas 4 crianças com idade variando entre 8 anos e 3 meses e 12 anos e 2 meses. Foram utilizados: listas de palavras monossílabas, dissílabas, palavras sem sentido e sentenças, Escala de Integração Auditiva Significativa para Crianças Pequenas (IT-MAIS) e Questionário de Avaliação da Linguagem Oral (MUSS), categorias de linguagem e audição. Todas as listas foram aplicadas em cabine acústica, à viva-voz, em campo livre, no silêncio. Resultados: Os resultados apresentaram média de 69,5% para a lista de palavras monossílabas, 87,75% para a lista de palavras dissílabas, 89,92% para a lista de sílabas sem sentido e 92,5% para a lista de sentenças. Conclusão: O processo terapêutico aplicado, que incluiu o uso do AASI bilateral, foi extremamente satisfatório, uma vez que possibilitou o desenvolvimento máximo das habilidades auditivas.

ABSTRACT Purpose: To analyze speech perception in children with pre-lingual hearing loss with auditory neuropathy spectrum disorder users of bilateral hearing aid. Methods: This is a descriptive and exploratory study carried out at the Research Center Audiological (HRAC/USP). The study included four children aged between 8 years and 3 months and 12 years and 2 months. Lists of monosyllabic words, two syllables, nonsense words and sentences, the Infant Toddler-Meaningful Auditory Integration Scale (IT-MAIS) and the Meaningful Use of Speech Scale (MUSS), hearing, and language categories were used. All lists were applied in acoustic booth, with speakers, in free field, in silence. Results: The results showed an average 69.5% for the list of monosyllabic words, 87.75% for the list of two-syllable words, 89.92% for the list of nonsense syllables, and 92.5% for the list of sentences. Conclusion: The therapeutic process that includes the use of bilateral hearing aid was extremely satisfactory, since it allowed the maximum development of auditory skills.

Indications and contraindications of auditory brainstem implants: systematic review and illustrative cases.

The number of non-neurofibromatosis type 2 (NF2) indications for auditory brainstem implant (ABI) in the literature is increasing. The objective of this study was to analyze and discuss the indications for ABI. Retrospective chart review and systematic review were conducted at Quaternary referral skull base center and referring centers. Analysis of ABI cases with non-NF2 indications and systematic review presenting non-NF2 ABI cases were performed. Fourteen referred cases with ABI were identified. All cases had unsatisfactory results of ABI and all could have been rehabilitated with a cochlear implant (CI). Of these 14 cases, 9 improved with a cochlear implant, and 2 with a hearing aid, two are still planned for CI, one received bilateral CI, no ABI. In literature, we found 31 articles presenting 144 non-NF2 ABI cases with at least 7 different indications other than NF2. ABI should be restricted to those patients who have no other rehabilitation options. Patency of the cochlea and evidence of an intact cochlear nerve should be examined with imaging and electrophysiologic testing. Sometimes a CI trial should be planned prior to proceeding with ABI. We have shown that in many cases a CI is still possible and CI provided better results than ABI. In vestibular schwannoma in the only hearing ear, cochlear otosclerosis, temporal bone fractures, (presumed) bilateral traumatic cochlear nerve disruption, auto-immune inner ear disease and auditory neuropathy primarily CI are indicated. Traumatic bilateral cochlear nerve disruption is exceptionally unlikely. In cochlear nerve aplasia, testing should be performed prior to meeting indications for ABI. In malformations, ABI is indicated only in severe cochlear hypoplasia or cochlear aplasia.

[Effectiveness of cochlear implantation in children with auditory neuropathy and cochlear nerve aplasia].

OBJECTIVE: The aim of this study is to assess of cochlear implantation in children with auditory neuropathy and cochlear nerve aplasia by using Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR). METHODS: Twenty one children with cochlear implants participated in this study. They all received cochlear implant surgery at our hospital from January 2004 to October 2010. All children had hearing aid trial and hearing and speech rehabilitation before surgery at least three months.Nine children (7 male, 2 female) were diagnosed with auditory neuropathy, twelve (7 male, 5 female) with cochlear nerve aplasia. Twenty children (10 male, 10 female) with sensorineural hearing loss served as a control group. All the children received cochlear implant for more than six months. Forty two children with normal hearing served as another control group which were divided into three subgroups according to their age.Group A included 18 children aged under two yrs, group B consisted of 16 children aged from two to four yrs and group C comprised eight children aged above four yrs. CAP and SIR were used to evaluate among all the children and the scores were compared. RESULTS: The CAP scores of children with auditory neuropathy, cochlear nerve aplasia, sensorial neural hearing loss and the three subgroups children with normal hearing were 4.44 ± 1.50, 4.83 ± 1.69, 4.55 ± 1.66, 5.22 ± 1.11, 6.75 ± 0.45 and 7.00 ± 0.00 respectively, and SIR scores were 2.66 ± 1.11, 2.33 ± 1.15, 2.40 ± 0.75, 2.56 ± 1.04, 4.12 ± 0.81 and 5.00 ± 0.00 respectively. There were significant differences among the six groups for CAP scores(χ(2) = 35.481, P < 0.001) and SIR scores(χ(2) = 40.549, P < 0.001).No significant differences for CAP and SIR scores were observed between children with auditory neuropathy/cochlear nerve aplasia and sensorial neural hearing loss as well as group A (P > 0.05 for each), and there were significant differences were shown between children with auditory neuropathy/cochlear nerve aplasia and group B as well as group C (P < 0.01 for each aplasia). CONCLUSIONS: The auditory and speech capabilities of children with auditory neuropathy and cochlear nerve deficiency can can get benefits from cochlear implants as children with sensorineural hearing loss, however not achieve the level of those with normal hearing after cochlear implantation. The long term effects still need follow-up and evaluation.

Cochlear implant electrode array misplacement: a cautionary case report.

OBJECTIVE: To report a series of pitfalls and complications in a case of cochlear implantation. METHOD: Case report. RESULTS: An 11-year-old boy affected by auditory neuropathy underwent cochlear implantation. Intra-operative assessment was apparently consistent with correct insertion of the electrode array into the cochlea. However, subsequent high resolution computed tomography revealed that the entire electrode array was curled up within the vestibule. Revision surgery was complicated by cerebrospinal fluid leakage. A straight probe was repeatedly inserted into the internal auditory canal, before conversion to a canal wall down procedure and appropriate positioning of the electrode array. CONCLUSION: In this case, mild anteriorisation of the facial nerve created an awkward insertion angle for the electrode array via the retro-facial route, which may have triggered the described series of adverse events.

Rate of neural recovery in implanted children with auditory neuropathy spectrum disorder.

OBJECTIVES: The study objectives were to compare the rate of neural recovery and speech perception performance in children with auditory neuropathy spectrum disorder (ANSD) and children with sensorineural hearing loss (SNHL) from other etiologies. STUDY DESIGN: Cohort study. SETTING: Academic hospital and cochlear implant center. SUBJECTS AND METHODS: Ten children with ANSD were matched based on type of implant and age at implantation with peers diagnosed with SNHL. Electrically evoked compound action potential (ECAP) recovery functions were obtained to measure neural refractory behaviors in response to stimulation from the cochlear implant. Speech perception performance was measured using speech recognition thresholds (SRTs) for monosyllable and spondee word stimuli. These outcome measures were compared between groups. RESULTS: There was no difference in average recovery function exponent in children with ANSD compared to children with SNHL. Similarly, there were no differences in average SRTs in quiet and in noise in children with ANSD compared to children with SNHL. Relationships between SRT and recovery rate were not present within groups or for all subjects for SRT in quiet, but a significant relationship was found for all subjects for SRT in noise (P = .04). CONCLUSIONS: Dyssynchronous neural activity in ANSD may affect temporal encoding of electrical stimulation from a cochlear implant. As a group, children with ANSD did not demonstrate slower neural recovery compared to those with SNHL, but there was slower neural recovery observed for some subjects. The utility of ECAP recovery functions on optimizing the stimulation rate for individual patients with ANSD requires further investigation.

Cochlear implantation in a Mandarin Chinese-speaking child with auditory neuropathy.

Auditory neuropathy (AN) is a hearing disorder characterized by the preservation of outer hair cell function despite the absence of auditory brainstem responses. The pathophysiology and etiology of this condition remain unknown. Recent studies have shown that some patients with AN benefit significantly from cochlear implantation. These patients have all been native speakers of Western languages. A 3-year-old Mandarin-speaking boy was referred to our center because of speech delay. After a series of audiological surveys, retro-cochlear lesion was impressed. During the 2-year period of rehabilitation, poor speech discrimination out of proportion to aided hearing thresholds led to the diagnosis of auditory neuropathy. Because of the limited benefit from amplification, he received a cochlear implant. Significant improvement of speech perception skills assessed by a Mandarin auditory perception test was noted shortly after implantation. The post-implantation performance in this Mandarin-speaking child was consistent with that of reports for implantees speaking Western languages. For Mandarin-speaking children with AN who fail to benefit from conventional treatment, cochlear implantation may be a good alternative choice.

Hearing restoration with auditory brainstem implants after radiosurgery for neurofibromatosis type 2.

The auditory brainstem implant (ABI) is designed to restore useful auditory sensations in patients with neurofibromatosis Type 2 (NF2). The implantation is usually performed at the time of tumor removal in patients who do not undergo radiation treatment. The authors evaluated the performance of ABIs in three patients with NF2 in whom vestibular schwannoma continued to grow after radiation treatment. These three patients with NF2 received a 21-channel ABI; a translabyrinthine approach was used for both the tumor removal and the ABI placement. The interval between radiosurgery and the tumor removal plus device implantation ranged from 2 to 11 years. In all cases, the tumor was growing and the patients presented with total deafness. The mean number of active electrodes in these three patients was equivalent to the average results reported in other patients who received ABIs. The patients in this study used the ABI regularly for everyday life and obtained useful levels of environmental sound recognition. It is concluded that hearing function can be rehabilitated using ABIs in patients with NF2, even if radiosurgery fails to control the tumor growth.