Peripheral vestibular pathology in Mondini dysplasia

A Peculiar Case of Ossicular Chain Fixation and Enlarged Vestibular Aqueduct

We present the case of a patient treated as affected by conductive hearing loss due to recurrent otitis, then as a juvenile otosclerosis, who was finally diagnosed as affected by bilateral ossicular chain fixation and enlarged vestibular aqueduct by means of cone-beam CT.

Vestibular anomalies and dysfunctions in children with inner ear malformations: A narrative review

About 20% of children with congenital hearing loss present malformations of the inner ear. In the past few years much has been understood about the morphology and function of the anterior part of the labyrinth, since hearing loss may have a dramatic effect on the overall development of a child. Nowadays, for most of them, a chance for hearing rehabilitation is available, making hearing loss a treatable condition. The anomalies range from the lack of development of the whole inner ear to specific anomalies of isolated structures. Despite the frequent concomitant involvement of the posterior part of the labyrinth, this part of the inner ear is frequently neglected while discussing its morphology and dysfunction. Even though vestibular and balance function/dysfunction may have a significant impact on the global development of children, very little is known about these specific disorders in patients with inner ear malformations. The aim of this review is to summarize the available literature about vestibular anomalies and dysfunctions in children with inner ear malformations, discussing what is currently known about the topic.

Establishment of Reference Values for Early Auditory Preverbal Skills of Children with Cochlear Implants

Auditory and verbal abilities of children with early cochlear implant (CI) surgery usually take some time to develop, and a reference index of early development for horizontal comparisons is urgently needed to guide the mapping process and adjust rehabilitation programs. Therefore, the aim of this study was to establish a reference value for early auditory preverbal skills development in children with CI and investigate the developmental curve and influencing factors for these children. The LittlEARS® Auditory Questionnaire (LEAQ) scores of 287 eligible Chinese participants were obtained at 1, 2, 3, 6, 9, 12, 18, 24, 28, and 36 months interval after CI activation. The median and standard deviation of the LEAQ score of each hearing stage for these children with different activation ages were calculated to establish the reference values. Quadratic regression was conducted to fit the expected developmental curve of the LEAQ score (y=-0.057x2+2.55x+5.45 [0 to 20 months]). With a linear mixed-effects model, we found that the receptive auditory behavior increased rapidly after CI activation, while expressive language skills developed at a steady rate. We also found that the following factors all significantly influenced the LEAQ: the duration of CI use, the development quotient, age of implantation and activation, and the presence of large vestibular aqueduct syndrome or auditory neuropathy spectrum disorder. The reference values and the expected developmental curve for the LEAQ in children with CI established by the present study provides guidance to clinicians and parents as well as realistic expectations regarding language and speech outcomes.

Vestibular function in children with cochlear implant: Impact and evaluation

Over the last 30 years, cochlear implant (CI) has been dedicated to improving the rehabilitation of hearing impairments. However, CI has shown potential detrimental effects on vestibular function. For children, due to atypical symptoms and difficulty in cooperating with vestibular function tests, systematic and objective assessments of vestibular function with CI have been conducted sparsely. This review focuses on the impact of vestibular function in children with CI and summarized the evaluation of vestibular function in children. In addition, some recommended strategies are summarized and proposed.

Direct Functional Protein Delivery with a Peptide into Neonatal and Adult Mammalian Inner Ear In Vivo

The aim of this study was to study an antimicrobial peptide (AMP), aurein 1.2, which substantially increased protein delivery directly into multiple mammalian inner-ear cell types in vivo. Different concentrations of aurein 1.2 with superpositively charged GFP (+36 GFP) protein fused with Cre recombinase were delivered to postnatal day 1-2 (P1-2) and adult cochleae of Cre reporter transgenic mice with various delivery methods. By cochleostomy at different concentrations of aurein 1.2-+36 GFP (1 μM, 5 μM, 22.5 μM, and 50 μM, respectively), the tdTomato (tdT) expression was observed in outer hair cells (OHCs; 20.77%, 23.02%, 76.36%, and 92.47%, respectively) and inner hair cells (IHCs; 14.90%, 44.50%, 89.59%, and 96.13%, respectively) in the cochlea. The optimal concentration was 22.5 μM with the highest transfection efficiency and the lowest cytotoxicity. Wide-spread tdT signals were detected in the cochlear-supporting cells, utricular-supporting cells, auditory nerve, and spiral ligament in neonatal and adult mice. Compared to cochleostomy, injection through the round window membrane (RWM) also produced highly efficient tdT+ labeled cells with less cell loss. In summary, the peptide aurein 1.2 fused with +36 GFP dramatically expanded the target cells with increased efficiency in direct protein delivery in the inner ear. Aurein 1.2-+36 GFP has the potential to be developed as protein-based therapy in regeneration and genome editing in the mammalian inner ear.

Histopathology of Inner Ear Malformations: Potential Pitfalls for Cochlear Implantation

HYPOTHESIS

The presence of bony inner ear malformations may associate with a number of anatomical abnormalities affecting the middle ear structures. Those malformations may create pitfalls and complications for cochlear implantation.

BACKGROUND

Inner ear malformations associate with varying degrees of hearing loss, and frequently require cochlear implantation for hearing rehabilitation. Therefore, the abnormalities affecting the middle- and inner-ear structures may increase the risk of surgical complications.

METHODS

We examined 38 human temporal bones from donors with bony inner ear malformations. Using light microscopy, we analyzed the presence of abnormalities in the structures of the middle- and inner-ear.

RESULTS

Our collection comprises of 38 specimens with inner-ear malformations (cochlear aplasia, n = 3; cochlear hypoplasia, n = 30; incomplete partition, n = 3; isolated vestibular malformation, n = 2). The anatomy of the middle ear was abnormal in most temporal bones with cochlear aplasia, cochlear hypoplasia, and incomplete partition type I (40%-100%). Some of those abnormalities (hypoplastic or obliterated mastoid, 55.2%; aplastic or obliterated round window, 71.0%; aberrant course of the facial nerve, 36.8%) may hinder the access to the round window using the conventional facial recess approach for cochlear implantation. The cochlear nerve and associated bony structures (internal auditory canal and bony canal for cochlear nerve) were normal in 71.0% of all temporal bones with inner ear malformations.

CONCLUSION

Each different type of malformation may create specific surgical challenges to surgeons. Comprehensive preoperative imaging is fundamental toward the surgical success of cochlear implants in patients with malformations. Alternatives to circumvent those middle- and inner-ear abnormalities and potential complications are further discussed.

Speech development in young children with Mondini dysplasia who had undergone cochlear implantation

OBJECTIVE

The purpose of this study was to investigate the development of speech skills in young children with Mondini dysplasia and age-matched deaf children with radiologically normal inner ears over a period of 5 years after cochlear implantation (CI).

METHODS

In total, 700 congenitally severely to profoundly deaf children (281 girls and 419 boys) participated in this study. All of the participants had undergone unilateral CI surgery before 36 months of age. The participants were categorized into two groups based on the absence or presence of Mondini dysplasia in the implanted ear, as assessed via high-resolution, thin-slice computerized tomography or magnetic resonance imaging: group A comprised 592 children with radiologically normal inner ears and group B comprised 108 children with Mondini dysplasia. The Meaningful Use of Speech Scale (MUSS) and Speech Intelligibility Rating (SIR) were used to evaluate the speech performance of all young children at various time points: pre-surgery and at 1, 3, 6, 12, 24, 36, 48, and 60 months after switch-on programming.

RESULTS

The mean scores of SIR and MUSS in children from both group A and group B showed significant improvements over time. No significant differences were found in the mean scores of SIR between the two groups at any time interval during the 5-year follow-up. The mean score of MUSS was significantly different between group A and group B at 12, 24, and 36 months after implantation, whereas no obvious differences were noted pre-surgery, and at 1, 3, 6, 48, and 60 months post-operation.

CONCLUSIONS

Young children with Mondini dysplasia develop their speech skills at a fast rate and achieve similar speech acquisition compared to age-matched children with radiologically normal inner ears 5 years post-operation. Therefore, CI is an effective intervention method for young children with Mondini dysplasia.