Cochlear Implant Surgery Through Round Window Approach Is Always Possible.

OBJECTIVES: The benefit of round window (RW) approach for cochlear implant (CI) has been well studied. Because the RW represents a natural door to scala tympani, it facilitates precise electrode insertion. Atraumatic electrode insertion can also be performed without drilling the cochlear lateral wall. However, the RW approach has several limitations. The purpose of this study is to describe successful CI surgeries utilizing the RW approach except for severe cases of temporal bone anomaly. The authors' successful surgical solution for cases involving difficult RW access is also described. MATERIALS AND METHODS: We retrospectively analyzed 377 consecutive surgeries of cochlear implantation performed between June 2010 and December 2018 by a single experienced surgeon. Standard and alternative procedures were used according to anatomical variations. Standard procedures included modified techniques of mastoidectomy in the RW approach, opening of facial recess, exposure of RW membrane, and electrode insertion. Difficult cases involving severe rotated cochlea or hypoplastic mastoid were successfully treated with RW insertion using alternative procedures such as external auditory canal (EAC) wall mobilization and endomeatal approach. RESULTS: We performed CI surgery through a reproducible RW technique in two cases involving endomeatal approach and three cases of EAC mobilization. Other cases were treated using the standard procedure. CONCLUSION: Cochlear implant surgery through RW is reliable, safe, and effective. The RW technique is reproducible via several surgical procedures in most CI cases. Identification and safe exposure of RW membrane is a prerequisite for successful electrode insertion in cochlear implant surgery.

Optimizing maps for electric acoustic stimulation users.

OBJECTIVES: To optimize patient's maps in Electric Acoustic Stimulation (EAS) users based on the degree of post-operative aided hearing thresholds. METHODS: Twenty-one adult EAS patients participated in this study. Patients were subdivided into three groups, based on their unaided hearing threshold: (1) electric complementary (EC, n = 6) patients with ≤30 dB HL at 125-500 Hz with severe to profound hearing loss at higher frequencies who only use electric stimulation, (2) EAS (n = 8) patients with 30-70 dB HL from 125 to 250 Hz and profound hearing loss in high frequencies who use combined EAS, and (3) Marginal-EAS (M-EAS, n = 7) patients with 70-95 dB HL at frequencies ≤250 Hz who use combined EAS. Sentence perception in noise, melodic contour identification, and subjective preference were measured using Full Overlap, Narrow Overlap, Gap, and Meet maps. RESULT: Of the 21 patients that participated, 12 subjects were classified as complete hearing preservation and 9 subjects were classified as partial hearing preservation. The highest performing maps in sentence-in-noise perception and melodic contour identification were Gap, Meet, and Full Overlap for the EC, EAS, and the M-EAS groups, respectively. These results are consistently across different test materials and align with subject preference as well. CONCLUSION: These results suggest that clinical fitting in EAS listening should be individually tailored. EAS performance can be enhanced by optimizing maps between acoustic and electric stimulation based on the degree of aided hearing thresholds.

Error Patterns Analysis of Hearing Aid and Cochlear Implant Users as a Function of Noise.

BACKGROUND AND OBJECTIVES: Not all impaired listeners may have the same speech perception ability although they will have similar pure-tone threshold and configuration. For this reason, the present study analyzes error patterns in the hearing-impaired compared to normal hearing (NH) listeners as a function of signal-to-noise ratio (SNR). SUBJECTS AND METHODS: Forty-four adults participated: 10 listeners with NH, 20 hearing aids (HA) users and 14 cochlear implants (CI) users. The Korean standardized monosyllables were presented as the stimuli in quiet and three different SNRs. Total error patterns were classified into types of substitution, omission, addition, fail, and no response, using stacked bar plots. RESULTS: Total error percent for the three groups significantly increased as the SNRs decreased. For error pattern analysis, the NH group showed substitution errors dominantly regardless of the SNRs compared to the other groups. Both the HA and CI groups had substitution errors that declined, while no response errors appeared as the SNRs increased. The CI group was characterized by lower substitution and higher fail errors than did the HA group. Substitutions of initial and final phonemes in the HA and CI groups were limited by place of articulation errors. However, the HA group had missed consonant place cues, such as formant transitions and stop consonant bursts, whereas the CI group usually had limited confusions of nasal consonants with low frequency characteristics. Interestingly, all three groups showed /k/ addition in the final phoneme, a trend that magnified as noise increased. CONCLUSIONS: The HA and CI groups had their unique error patterns even though the aided thresholds of the two groups were similar. We expect that the results of this study will focus on high error patterns in auditory training of hearing-impaired listeners, resulting in reducing those errors and improving their speech perception ability.

HiRes with Fidelity 120 benefit in native speakers of Korean.

In HiRes 120 sound processing, the spectral bands are created by precisely varying the proportion of current delivered simultaneously to adjacent electrodes through active current steering. The purpose of this study was to examine performance of native Korean speakers with HiRes 120. Eleven adults with postlinguial hearing loss participated in the study. The difference between baseline and three-month HiRes 120 performance was significant for all tests (p < 0.05). For monosyllabic words, eight subjects obtained higher scores with HiRes 120. For the Hearing in Noise Test (HINT), ten subjects obtained higher scores with standard HiRes. These results show Korean speakers exhibit improved speech understanding in quiet and in noise with HiRes 120. All subjects preferred the new HiRes 120 sound processing option.

A cochlear schwannoma presenting with sudden hearing loss.

A cochlear schwannoma is a rare tumor that arises from the cochlear nerve. Clinically, a cochlear schwannoma mimics the clinical features of sudden deafness or Meniere's disease. We report a case of cochlear schwannoma that presented with sudden hearing loss, which was diagnosed with gadolinium-enhanced magnetic resonance imaging and removed using a transotic approach.

Reversibility of experimental cholesteatoma epithelium using Mongolian gerbils.

CONCLUSION: The results of this study encourage our belief that some cholesteatomas can be managed using only conservative treatments. OBJECTIVE: We hypothesized that once cholesteatoma is in a normal environment, its cellular or molecular pathology can revert to those characteristic of normal epidermis. The aim of this study was to determine whether or not common molecular characteristics of cholesteatoma were reversible after removal of inductive factors in experimental cholesteatoma induced in gerbils. MATERIAL AND METHODS: We induced cholesteatoma using ear canal ligation in Mongolian gerbils. After ligation, the animals in the treated group were managed for 2 weeks. We examined differences between treated and untreated cholesteatomas using terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL) staining and an immunohistochemical technique using the proliferation markers proliferating cell nuclear antigen (PCNA) and cytokeratin (CK). RESULTS: With PCNA and CK 13/16, the untreated group showed positive staining in the suprabasal and basal cells, but the treated group showed weakly positive staining only in the basal cell layer. With TUNEL staining, there were more positive cells in the untreated than the treated group.

Immortalization of normal adult human middle ear epithelial cells using a retrovirus containing the E6/E7 genes of human papillomavirus type 16.

A human middle ear epithelial cell line (HMEEC-1) was established using human papillomavirus E6/E7 genes. HMEEC-1 has remained morphologically and phenotypically stable, even after 50 passages. The cells are anchorage-dependent and nontumorigenic when injected into nude mice. This cell line thus provides a new tool for the study of normal cell biology and the pathological processes associated with the epithelial cells of the middle ear in otitis media. HMEEC-1 will also be useful in the search for new drugs and biological agents for the treatment of otitis media.

Activation of a Src-dependent Raf-MEK1/2-ERK signaling pathway is required for IL-1alpha-induced upregulation of beta-defensin 2 in human middle ear epithelial cells.

beta-defensin 2 is produced by a variety of epithelial cell types in the body and exhibits potent antimicrobial activity against a variety of pathogens, including the bacteria that are most commonly associated with otitis media (OM). The human beta-defensin 2 (hBD-2) gene is an NF-kappa B regulated gene and a variety of proinflammatory stimuli can induce its expression. Although the presence of molecules of innate immunity such as lysozyme and lactoferrin has been demonstrated in the middle ear, to date there have been no reports on the expression of beta-defensin 2. In the present study, we demonstrate that beta-defensin 2 is expressed in the middle ear mucosa of humans and rats. We also show that it is expressed in a human middle ear epithelial cell line and that its expression is induced by proinflammatory stimuli such as interleukin 1 alpha (IL-1 alpha), tumor necrosis factor alpha (TNF-alpha), and lipopolysaccharide (LPS). Moreover, we demonstrate that the transcriptional activation of hBD-2 gene by IL-1 alpha is mediated through an Src-dependent Raf-MEK1/2-ERK signaling pathway.