Large-scale phenotyping of ABR P1-N1 amplitudes before and after exposure to noise in 69 strains of mice.

ABR wave I amplitude represents the synapse of auditory nerve fibers with the inner hair cell and is highly correlated with synapse counts. Cochlear synaptopathy, the loss of synaptic connections between inner hair cells and auditory nerve fibers, has been well-demonstrated in animal models of noise-induced hearing loss. The peak-to-peak wave I amplitude was determined at baseline and 2 weeks after noise exposure. We determined the ABR wave I amplitude at 80 dB SPL at the frequencies of 8, 12, 16, 24, and 32 kHz. A total of 69 strains (1-8 mice/strain) were analyzed. A statistically significant post-noise reduction in wave I amplitude was observed in all the tested frequencies (p < 0.00001). We identify distinct patterns of noise susceptibility and make this complete phenotypic dataset available for general use. This data establishes a new resource for the study of NIHL in mice and we hope this database will be a useful tool to expand the research in this field.

Cochlear implants: Insertion assessment by computed tomography.

BACKGROUND AND OBJECTIVES: Imaging exams play a key role in cochlear implants with regard to both planning implantation before surgery and quality control after surgery. The ability to visualize the three-dimensional location of implanted electrodes is useful in clinical routines for assessing patient outcome. The aim of this study was to evaluate linear and angular insertion depth measurements of cochlear implants based on conventional computed tomography. METHODS: Tools for linear and angular measurements of cochlear implants were used in computed tomography exams. The tools realized the insertion measurements in an image reconstruction of the CIs, based on image processing techniques. We comprehensively characterized two cochlear implant models while obviating possible changes that can be caused by different cochlea sizes by using the same human temporal bones to evaluate the implant models. RESULTS: The tools used herein were able to differentiate the insertion measurements between two cochlear implant models widely used in clinical practice. We observed significant differences between both insertion measurements because of their different design and construction characteristics (p = 0.004 and 0.003 for linear and angular measurements, respectively; t-test). The presented methodology showed to be a good tool to calculate insertion depth measurements, since it is easy to perform, produces high-resolution images, and is able to depict all the landmarks, thus enabling measurement of the angular and linear insertion depth of the most apical electrode contacts. CONCLUSION: The present study demonstrates practical and useful tools for evaluating cochlear implant electrodes in clinical practice. Further studies should measure preoperative and postoperative benefits in terms of speech recognition and evaluate the preservation of residual hearing in the implanted ear. Such studies can also determine correlations between surgical factors, electrode positions, and performance. In addition to refined surgical techniques, the precise evaluation of cochlear length and correct choice of cochlear implant characteristics can play an important role in postoperative outcomes.

SARS-CoV-2 infection with bilateral intralabyrinthine hemorrhage.

A 47-year-old woman presented with the complaint of sudden hearing loss associated with vertigo. Serological testing was positive for IgM and negative for IgG COVID-19 antibodies, with no other associated factors. Magnetic resonance imaging of the brain showed bilateral intralabyrinthine hemorrhage.

Bilateral facial paralysis secondary to temporal bone trauma: A case report and literature review.

When temporal bone fractures are associated with facial palsy (FP) evolution the medical team have no much time to make a decision: to do or not to do a surgical approach? How to evaluate the necessity? When to do it and when is the correct time?

Conservative management of petrous apex abscess and Gradenigo's syndrome in a diabetic patient: Case report and literature review.

The case reported evidences the possibility of nonsurgical treatment in patients with abscesses located in regions difficult to reach surgically due to surgical limitations or possible sequelae related to surgical procedure.

Progressive Asymmetry in Occupational Noise-Induced Hearing Loss: A Large Population-Based Cohort Study With a 15-Year Follow-Up.

BACKGROUND: To evaluate interaural differences between the right and left ears at frequencies from 0.25 to 8 kHz in 3 groups of workers from metallurgy companies. METHODS: This study is a cross-sectional cohort study. Workers were divided into 3 groups: (1) workers without occupational noise exposure and normal audiometric testing; (2) workers with 10 years of occupational noise exposure; and (3) workers with 15 years of occupational noise exposure. The interaural difference from 0.25 to 8 kHz was measured in each group. RESULTS: A total of 2103 workers were included. Of these, 483 workers had been exposed to noise in the workplace for 10 years and 216 workers for 15 years. Group 1, only at 4 and 6 kHz, the difference was statistically significant. Group 2, only at 3 , 4 , and 6 kHz, the difference was statistically significant. Group 3, the difference was statistically significant at the frequencies from 2 to 8 kHz. CONCLUSION: Asymmetry between the right and left ears was observed in all groups, with higher air-conduction thresholds in the left ear. It is important for otolaryngologists be aware that NIHL can also cause or accentuate asymmetry between the right and left ears over time.