scholarly journals Transient Conductive Hearing Loss Regulates Cross-Modal VGLUT Expression in the Cochlear Nucleus of C57BL/6 Mice

2020 ◽  
Vol 10 (5) ◽  
pp. 260 ◽  
Author(s):  
Takaomi Kurioka ◽  
Sachiyo Mogi ◽  
Taku Yamashita

Auditory nerve fibers synapse onto the cochlear nucleus (CN) and are labeled using the vesicular glutamate transporter-1 (VGLUT-1), whereas non-auditory inputs are labeled using the VGLUT-2. However, the underlying regulatory mechanism of VGLUT expression in the CN remains unknown. We examined whether a sound level decrease, without primary neural damage, induces cellular and VGLUT expression change in the CN, and examined the potential for neural plasticity of the CN using unilateral conductive hearing loss models. We inserted earplugs in 8-week-old mice unilaterally for 4 weeks and subsequently removed them for another 4 weeks. Although the threshold of an auditory brainstem response significantly increased across all tested frequencies following earplug insertion, it completely recovered after earplug removal. Auditory deprivation had no significant impact on spiral ganglion and ventral CN (VCN) neurons’ survival. Conversely, although the cell size and VGLUT-1 expression in the VCN significantly decreased after earplug insertion, VGLUT-2 expression in the granule cell lamina significantly increased. These cell sizes decreased and the alterations in VGLUT-1 and -2 expression almost completely recovered at 1 month after earplug removal. Our results suggested that the cell size and VGLUT expression in the CN have a neuroplasticity capacity, which is regulated by increases and decreases in sound levels. Restoration of the sound levels might partly prevent cell size decrease and maintain VGLUT expression in the CN.

2017 ◽  
Vol 21 (04) ◽  
pp. 318-322 ◽  
Author(s):  
Pricila Sleifer ◽  
Dayane Didoné ◽  
Ísis Keppeler ◽  
Claudine Bueno ◽  
Rudimar Riesgo

Introduction The tone-evoked auditory brainstem responses (tone-ABR) enable the differential diagnosis in the evaluation of children until 12 months of age, including those with external and/or middle ear malformations. The use of auditory stimuli with frequency specificity by air and bone conduction allows characterization of hearing profile. Objective The objective of our study was to compare the results obtained in tone-ABR by air and bone conduction in children until 12 months, with agenesis of the external auditory canal. Method The study was cross-sectional, observational, individual, and contemporary. We conducted the research with tone-ABR by air and bone conduction in the frequencies of 500 Hz and 2000 Hz in 32 children, 23 boys, from one to 12 months old, with agenesis of the external auditory canal. Results The tone-ABR thresholds were significantly elevated for air conduction in the frequencies of 500 Hz and 2000 Hz, while the thresholds of bone conduction had normal values in both ears. We found no statistically significant difference between genders and ears for most of the comparisons. Conclusion The thresholds obtained by bone conduction did not alter the thresholds in children with conductive hearing loss. However, the conductive hearing loss alter all thresholds by air conduction. The tone-ABR by bone conduction is an important tool for assessing cochlear integrity in children with agenesis of the external auditory canal under 12 months.


ORL ◽  
2021 ◽  
pp. 1-7
Author(s):  
Takahiro Nakashima ◽  
Akira Ganaha ◽  
Shougo Tsumagari ◽  
Takeshi Nakamura ◽  
Yuusuke Yamada ◽  
...  

We describe a dominant Japanese patient with progressive conductive hearing loss who was diagnosed with <i>NOG</i>-related symphalangism spectrum disorder (<i>NOG</i>-SSD), a spectrum of congenital stapes fixation syndromes caused by <i>NOG</i> mutations. Based on the clinical features, including proximal symphalangism, conductive hearing loss, hyper­opia, and short, broad middle, and distal phalanges of the thumbs, his family was diagnosed with stapes ankylosis with broad thumbs and toes syndrome (SABTT). Genetic analysis revealed a heterozygous substitution in the <i>NOG</i> gene, c.645C&#x3e;A, p.C215* in affected family individuals. He had normal hearing on auditory brainstem response (ABR) testing at ages 9 months and 1 and 2 years. He was followed up to evaluate the hearing level because of his family history of hearing loss caused by SABTT. Follow-up pure tone average testing revealed the development of progressive conductive hearing loss. Stapes surgery was performed, and his post-operative hearing threshold improved to normal in both ears. According to hearing test results, the stapes ankylosis in our SABTT patient seemed to be incomplete at birth and progressive in early childhood. The ABR results in our patient indicated the possibility that newborn hearing screening may not detect conductive hearing loss in patients with <i>NOG</i>-SSD. Hence, children with a family history and/or known congenital joint abnormality should undergo periodic hearing tests due to possible progressive hearing loss. Because of high success rates of stapes surgeries in cases of SABTT, early surgical interventions would help minimise the negative effect of hearing loss during school age. Identification of the nature of conductive hearing loss due to progressive stapes ankylosis allows for better genetic counselling and proper intervention in <i>NOG</i>-SSD patients.


1982 ◽  
Vol 91 (3) ◽  
pp. 304-309 ◽  
Author(s):  
Therese J. McGee ◽  
Jack D. Clemis

The purpose of this paper is not to propose that auditory brainstem response (ABR) be utilized for the assessment of conductive losses, but to define the effects of conductive hearing loss on the ABR when such a complication occurs. Conductive losses attenuate cochlear stimulation. Since wave V latency is inversely related to stimulus intensity, the magnitude of the conductive loss should be a predictor of the wave V latency delay. In this study, ABR wave V latencies from patients with known conductive losses due to canal occlusion, middle ear effusion, ossicular fixation and chain interruption were compared with latency values calculated from the magnitude of the loss. In those patients with occlusion of the external auditory canal and middle ear effusion, the shift of the wave V latency-intensity function correlated well with the air-bone gap. This correlation was poor for patients with ossicular chain disorders. In mixed hearing losses, the increased wave V latency due to the conductive component may totally mask an increase in latency caused by a retrocochlear component.


1985 ◽  
Vol 50 (4) ◽  
pp. 346-350 ◽  
Author(s):  
Michael P. Gorga ◽  
Jan K. Reiland ◽  
Kathryn A. Beauchaine

Click-evoked auditory brainstem responses were measured in a patient with high-frequency conductive hearing loss. As is typical in cases of conductive hearing loss, Wave I latency was prolonged beyond normal limits. Interpeak latency differences were just below the lower limits of the normal range. The Wave V latency-intensity function, however was abnormally steep. This pattern is explained by the hypothesis that the slope of the latency-intensity function is determined principally by the configuration of the hearing loss. In cases of high-frequency hearing loss (regardless of the etiology), the response may be dominated by more apical regions of the cochlea at lower intensities and thus have a longer latency.


2014 ◽  
Vol 8 ◽  
Author(s):  
Verónica Fuentes-Santamaría ◽  
Juan C. Alvarado ◽  
Diego F. López-Muñoz ◽  
Pedro Melgar-Rojas ◽  
María C. Gabaldón-Ull ◽  
...  

1994 ◽  
Vol 3 (2) ◽  
pp. 52-58 ◽  
Author(s):  
Carol L. Mackersie ◽  
David R. Stapells

Wave I latencies were used to predict the magnitude of conductive components in 80 infants and young children (122 ears) with normal hearing, conductive hearing loss due to otitis media or aural atresia, sensorineural hearing loss, and mixed hearing loss. Two prediction methods were used. The first method based predictions on a 0.03-ms wave I latency delay for each decibel of conductive hearing loss. The second method was based on a regression analysis of wave I latency delays and the magnitude of conductive component for the subjects in this study with normal cochlear status. On average, these prediction methods resulted in prediction errors of 15 dB or greater in over one-third of the ears with hearing loss. Therefore, the clinical use of wave I latencies to predict the presence or magnitude of conductive impairment is not recommended for infants and young children. Instead, bone-conduction ABR testing is recommended as a direct measure of cochlear status when behavioral evaluation is not possible.


1980 ◽  
Vol 89 (3_suppl) ◽  
pp. 200-206 ◽  
Author(s):  
Thomas J. Fria ◽  
Diane L. Sabo

Auditory brainstem responses (ABR) were recorded in 14 infants and toddlers and 12 school-age children with a previous history of recurrent otitis media with effusion (OME), or otoscopic and tympanometric evidence of persistent OME, or both. ABR tests were performed immediately before and after myringotomy and tympanostomy tube insertion in the younger subjects. For the school-age children, ABR tests were performed following otoscopy, tympanometry, and pure tone audiometry. The results demonstrate that the latency of both wave I and wave V of the ABR was sensitive (82% and 100%, respectively) to the presence of OME. Wave I also identified the absence of OME (specificity = 100%) whereas wave V did not (specificity = 25%). ABR latency was significantly decreased postoperatively in ears found to have OME, but not in ears found to have no OME. In the school-age subjects the ABR was used to predict the conductive hearing loss at 4000 Hz with less than a 20 dB error in virtually all subjects. The ABR latency delay was also found to be related to conductive hearing impairment at lower pure tone frequencies and to the average conductive loss at a variety of pure tone frequencies. Predictions of the presence of a conductive hearing loss from these relationships promise to be impressively accurate. The results suggest that the ABR can be a valuable tool for detecting the presence of conductive hearing impairment in infants and young children suspected to have OME and perhaps as an estimate of the degree of impairment.


Sign in / Sign up

Export Citation Format

Share Document