scholarly journals The design of a lumped parameter model considering the stimulus path of round window

2021 ◽  
Vol 29 ◽  
pp. 49-56
Author(s):  
Jong Hoon Kim ◽  
Min Gyu Park ◽  
Qun Wei ◽  
Ki Woong Seong ◽  
Jyung Hyun Lee
Keyword(s):  
Guinea Pigs ◽  
Round Window ◽  
Animal Experiments ◽  
Hearing Threshold ◽  
Auditory Brainstem ◽  
Oval Window ◽  
Lumped Parameter Model ◽  
Piezo Actuator ◽  
Lumped Parameter ◽  
Brainstem Response

BACKGROUND: Sound normally enters the ear canal, passes through the middle ear, and stimulates the cochlea through the oval window. Alternatively, the cochlea can be stimulated in a reverse manner, namely round window stimulation. The reverse stimulation is not well understood, partly because in classic lumped-parameter models the path of reverse drive during the round window stimulation is usually not considered. OBJECTIVE: The study goal is to gain a better understanding of the hearing mechanism during round window stimulation. METHODS: A piezo actuator was coupled to the oval and round window of the guinea pigs. The auditory brainstem response produced by the forward and reverse stimulation at four frequencies was recorded. RESULTS: The results show that the input voltage of the actuator required at the hearing threshold in the round window drive was higher than that in the oval window drive. In order to understand the data, we designed a lumped-parameter cochlear model that can simulate both forward and reverse drive. The model-predicted results were consistent with the experimental results. CONCLUSIONS: The response of the auditory system to stimulus of oval window and round window was quantified through animal experimentation, and guinea pigs were used as experimental animals. When the same stimulus was applied to the oval window and round window of the cochlea, the ABR signals were compared. A lumped parameter model was designed to incorporate the sound transmission paths in both oval and round window stimulation. The simulated results are consistent with those of animal experiments. This model will be useful in understanding the inner-ear response in round window.

An auditory profile of sclerosteosis

2014 ◽  
Vol 128 (4) ◽  
pp. 336-344 ◽  
Author(s):  
J M Potgieter ◽  
D W Swanepoel ◽  
B M Heinze ◽  
L M Hofmeyr ◽  
A A S Burger ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Middle Ear ◽  
Bone Growth ◽  
Round Window ◽  
Internal Auditory Canal ◽  
Auditory Brainstem ◽  
Oval Window ◽  
Speech Discrimination ◽  
Cross Sectional ◽  
Brainstem Response

AbstractObjective:To characterise auditory involvement secondary to excessive craniotubular bone growth in individuals with sclerosteosis in South Africa.Methods:This cross-sectional study assessed the auditory profile of 10 participants with sclerosteosis. An auditory test battery was used and results for each ear were recorded using descriptive and comparative analyses.Results:All participants presented with bilateral, mixed hearing losses. Of the 20 ears, hearing loss was moderate in 5 per cent (n = 1), severe in 55 per cent (n = 11) and profound in 40 per cent (n = 8). Air–bone gaps were smaller in older participants, although the difference was not statistically significant (p > 0.05). Computed tomography scans indicated pervasive abnormalities of the external auditory canal, tympanic membrane, middle-ear space, ossicles, oval window, round window and internal auditory canal. Narrowed internal auditory canals corresponded to poor speech discrimination, indicative of retrocochlear pathology and absent auditory brainstem response waves.Conclusion:Progressive abnormal bone formation in sclerosteosis involves the middle ear, the round and oval windows of the cochlea, and the internal auditory canal. The condition compromises conductive, sensory and neural auditory pathways, which results in moderate to profound, mixed hearing loss.

Therapeutic efficacy of topical application of dexamethasone to the round window niche after acoustic trauma caused by intensive impulse noise in guinea pigs

2011 ◽  
Vol 125 (7) ◽  
pp. 673-685 ◽  
Author(s):  
F-L Chi ◽  
M-Q Yang ◽  
Y-D Zhou ◽  
B Wang
Keyword(s):  
Topical Application ◽  
Guinea Pigs ◽  
Impulse Noise ◽  
Round Window ◽  
Spiral Ganglion ◽  
Cell Loss ◽  
Auditory Brainstem ◽  
Post Treatment ◽  
Brainstem Response ◽  
Round Window Niche

AbstractObjective:To assess the therapeutic efficacy of dexamethasone administered topically to the round window niche, following acoustic trauma induced by intensive impulse noise, in guinea pigs.Methods:Adult, male, albino guinea pigs with a normal Preyer's reflex were exposed to 80 impulse noises (peak value 167 dB, duration 0.5 ms, interval 2 s). Dexamethasone (40 mg/ml) or saline was then topically applied to the round window niche. Each animal's auditory brainstem response was measured before and one day after exposure, and three weeks after topical treatment. Cochlear morphology was examined to assess hair cell loss and spiral ganglion cell damage. To assess oxidative activity, cochlear malondialdehyde and superoxide dismutase concentrations were determined three weeks post-treatment. Following topical application, the pharmacokinetic characteristics of dexamethasone in cochlear perilymph were analysed using high-performance liquid chromatography.Results:Animals receiving dexamethasone showed reduced noise-induced outer hair cell loss (three weeks post-treatment), and significant attenuation of noise-induced auditory brainstem response threshold shifts (one day post-exposure and three weeks post-treatment), compared with controls. There was no difference in spiral ganglion morphology. Animals receiving dexamethasone also showed a significantly lower malondialdehyde concentration and a higher superoxide dismutase concentration, post-exposure. Following topical application, the perilymph dexamethasone level peaked at 5330.522 µg/ml (15 minutes post-treatment), and was 299.797 µg/ml 360 minutes later.Conclusion:Topical application of dexamethasone to the round window niche has protective effects against intensive impulse noise induced trauma in the guinea pig cochlea. This drug can diffuse into the inner ear through the round window membrane and persist in the perilymph for a relatively long period. The mechanism of protection may involve an anti-oxidant effect.

scholarly journals Estrogen inhibits apoptosis of pericytes in the cochlea stria vascularis through downregulating TMEM16A

2020 ◽  
Author(s):  
Xuerui Li ◽  
Yang Zhang ◽  
Long Chen ◽  
Ziyi Feng ◽  
Ketao Ma ◽  
...  
Keyword(s):  
Stria Vascularis ◽  
Animal Experiments ◽  
Hearing Threshold ◽  
Auditory Brainstem ◽  
Protective Role ◽  
Apoptosis Rate ◽  
Aged Mice ◽  
Ovariectomized Mice ◽  
Brainstem Response

Abstract Background: Currently, the specific mechanism of estrogen (E2) in protecting presbycusis is not clear. This study aimed to investigate whether E2 could affect the apoptosis of capillary pericytes (PCs) of cochlear stria vascularis (SV) in aged C57BL/6J mice by regulating transmembrane member 16A (TMEM16A), such that it plays a protective role in presbycusis.Methods: The model of C57BL/6J ovariectomized mice was established, and E2 was administered for 2 months. The hearing threshold was measured by auditory brainstem response (ABR). The changes in the cochlea were measured using hematoxylin-eosin (HE) and electron microscopy. qRT-PCR was used to examine the expression of TMEM16A and apoptosis-related protein mRNA. The PCs were cultured in vitro, and the cell senescence model was established by the continuous passage method. TMEM16A expression was assessed using immunofluorescence. Flow cytometry was performed to explore the apoptosis rate.Results: The results of animal experiments showed that E2 intervention could reduce hearing loss and improve the atrophy of cochlear SV, loss of PC chromatin organelles, cytoplasmic swelling and nuclear porosity in aged mice. E2 also decreased the mRNA expression of TMEM16A, Caspase-3 and Bax in cochlear SV of aged mice and upregulated the expression of Bcl-2 mRNA. Cellular experiments showed that E2 could downregulate the expression of TMEM16A, and E2 or T16Ainh-A01(a specific blocker of TMEM16A) could reduce the apoptosis rate of PCs in aged mice.Conclusions: E2 may inhibit the apoptosis of PCs through downregulating the expression of TMEM16A, which plays a protective role in presbycusis. This study may provide a novel potential treatment and prevention method for presbycusis.

Antioxidant Enzyme Levels Inversely Covary with Hearing Loss After Amikacin Treatment

2003 ◽  
Vol 14 (03) ◽  
pp. 134-143 ◽  
Author(s):  
James J. Klemens ◽  
Robert P. Meech ◽  
Larry F. Hughes ◽  
Satu Somani ◽  
Kathleen C.M. Campbell
Keyword(s):  
Hearing Loss ◽  
Enzyme Activity ◽  
Antioxidant Enzyme ◽  
Guinea Pigs ◽  
Auditory Brainstem ◽  
Antioxidant Enzyme Activity ◽  
Control Group ◽  
Glutathione S Transferase ◽  
Brainstem Response ◽  
The Difference

This study's purpose was to determine if a correlation exists between cochlear antioxidant activity changes and auditory function after induction of aminoglycoside (AG) ototoxicity. Two groups of five 250-350 g albino guinea pigs served as subjects. For 28 days, albino guinea pigs were administered either 200 mg/kg/day amikacin, or saline subcutaneously. Auditory brainstem response testing was performed prior to the first injection and again before sacrifice, 28 days later. Cochleae were harvested and superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase activities and malondialdehyde levels were measured. All antioxidant enzymes had significantly lower activity in the amikacin group (p ≤ 0.05) than in the control group. The difference in cochlear antioxidant enzyme activity between groups inversely correlated significantly with the change in ABR thresholds. The greatest correlation was for the high frequencies, which are most affected by aminoglycosides. This study demonstrates that antioxidant enzyme activity and amikacin-induced hearing loss significantly covary.

High Blood Glucose Levels Affect Auditory Brainstem Responses after Acoustic Overexposure in Rats

2021 ◽  
pp. 1-8
Author(s):  
Jae-Hun Lee ◽  
Sang Hee Ji ◽  
Jae Yun Jung ◽  
Min Young Lee ◽  
Chi-Kyou Lee
Keyword(s):  
Blood Glucose ◽  
Hearing Threshold ◽  
Auditory Brainstem ◽  
Diabetic Rats ◽  
Control Groups ◽  
High Blood Glucose ◽  
Glucose Levels ◽  
Blood Glucose Levels ◽  
Hearing Function ◽  
Brainstem Response

Introduction: Diabetes mellitus (DM) is a systemic disease characterized by hyperglycemia and several pathological changes. DM-related hearing dysfunctions are associated with histological changes. Here, we explore hearing function and synaptic changes in the inner hair cells (IHCs) of rats with streptozotocin (STZ)-induced diabetes. Methods: STZ was injected to trigger diabetes. Rats with DM were exposed to narrow-band noise (105 dB SPL) for 2 h, and hearing function was analyzed 1, 3, 7, and 14 days later. Both the hearing threshold and the peak 1 amplitude of the tone auditory brainstem response were assessed. After the last functional test, animals were sacrificed for histological evaluation. Results: We found no changes in the baseline hearing threshold; however, the peak 1 amplitude at the low frequency (4 kHz) was significantly higher in both DM groups than in the control groups. The hearing threshold had not fully recovered at 14 days after diabetic rats were exposed to noise. The peak 1 amplitude at the higher frequencies (16 and 32 kHz) was significantly larger in both DM groups than in the control groups. The histological analysis revealed that the long-term DM group had significantly more synapses in the 16 kHz region than the other groups. Conclusions: We found that high blood glucose levels increased peak 1 amplitudes without changing the hearing threshold. Diabetic rats were less resilient in threshold changes and were less vulnerable to peak 1 amplitude and synaptic damage than control animals.

scholarly journals Comparison of auditory steady state response (ASSR) & auditory brainstem response (ABR) hearing thresholds in young children.

2019 ◽  
Vol 2 (1) ◽  
pp. 17-21
Author(s):  
Adil Munir ◽  
Nazia Mumtaz ◽  
Ghulam Saqulain ◽  
Munir Ahmad
Keyword(s):  
Steady State ◽  
Hearing Threshold ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Steady State Response ◽  
Female Ratio ◽  
State Response ◽  
Hearing Thresholds ◽  
Auditory Steady State Response ◽  
Brainstem Response

Objective: Hearing loss (HL) with a local prevalence of 5.7%, is the commonest childhood disability, requiring Early Hearing Detection and Intervention (EHDI) programs to reduce the disability burden. Knowing the degree, type and configuration of HL is prerequisite for appropriate amplification, with Automated Auditory Brainstem Responses (ABR) being commonly used for this purpose, however Auditory Steady State Response (ASSR) has been recently introduced in the region. This study was conducted to compare ABR to ASSR, as an early diagnostic tool in children under five years of age. Methodology: This cross-sectional comparative study was performed at the Auditory Verbal Institute of Audiology and Speech (AVIAS) clinics in Rawalpindi and Islamabad, from December 2016 to September 2017. It included thirty-two cases (n=32) who visited AVIAS clinics for hearing assessment and conformed to the investigative protocol using non probability convenient sampling technique, and subjected to both ABR and ASSR for comparative purposes. Correlations were calculated between the thresholds obtained by ABR and ASSR. Results: N=32 children (64 ears) with male female ratio of 2.2:1 and mean age of 33.50±17.73 months were tested with ABR and ASSR for hearing thresholds and correlation coefficient between 2KHz, 4KHz ASSR and average of both with ABR was calculated to be 0.92 and 0.90 and 0.94 respectively. Conclusion: ASSR provides additional frequency specific hearing threshold estimation compared to C-ABR, essentially required for proper setting of amplification devices. 

Effects of noise exposure on neonatal auditory brainstem response thresholds in pregnant guinea pigs at different gestational periods

2016 ◽  
Vol 43 (1) ◽  
pp. 78-86
Author(s):  
Chihiro Morimoto ◽  
Kazuhiko Nario ◽  
Tadashi Nishimura ◽  
Ryota Shimokura ◽  
Hiroshi Hosoi ◽  
...  
Keyword(s):  
Auditory Brainstem Response ◽  
Guinea Pigs ◽  
Noise Exposure ◽  
Auditory Brainstem ◽  
Brainstem Response ◽  
Response Thresholds

The Auditory Brainstem Response of Aged Guinea Pigs

1998 ◽  
Vol 118 (5) ◽  
pp. 673-680 ◽  
Author(s):  
Neil J. Ingham, Sally K. Thornton,
Keyword(s):  
Auditory Brainstem Response ◽  
Guinea Pigs ◽  
Auditory Brainstem ◽  
Brainstem Response
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