scholarly journals The Effects of Round Window Membrane Injury and the Use of a Model Electrode Application on Hearing in Rats

2021 ◽  
pp. 014556132199018
Author(s):  
Murat Koc ◽  
Abdullah Dalgic ◽  
Mehmet Ziya Ozuer
Keyword(s):  
Hearing Loss ◽  
Cochlear Implant ◽  
Round Window ◽  
Mechanical Trauma ◽  
Round Window Membrane ◽  
Albino Rats ◽  
Topical Steroids ◽  
Distortion Product ◽  
Significant Difference ◽  
Group 3

Objective: To investigate the effects of the mechanical trauma to the round window, a model electrode inserted into the scala tympani on the cochlear reserve, and the efficacy of topical steroids in preventing hearing loss. Materials and Methods: 21 male Wistar Albino rats were equally categorized into three groups. In all groups an initial mechanical injury to round window was created. Only subsequent dexamethasone injection was administrated into the cochlea in the subjects of group 2 while a multichannel cochlear implant guide inserted into the cochlea prior to dexamethasone administration for group 3. Distortion product otoacoustic emissions (DPOAEs) were obtained prior to and immediately after the surgical injury, eventually on postoperative seventh day (d 7). Mean signal/noise ratios (S/Ns) obtained at 2000, 3000, and 4000 Hz were calculated. Data sets were compared with non-parametric statistical tests. Results: The early intraoperative mean S/Ns were significantly less than preoperative measurements for group 1 and 2; however, preoperative and postoperative d 7 average S/Ns did not differ. There was statistically significant difference between preoperative, intraoperative and postoperative d 7 average S/Ns for group 3. Conclusion: We observed that hearing was restored approximately to the preoperative levels following early postoperative repair. However, an electrode insertion into the cochlea via round window subsequent to mechanical trauma seems to cause a progressive hearing loss. Therefore, a special care must be taken to avoid the injury to the round window membrane in the course of the placement of a cochlear implant electrode and surgery for the chronic otitis media.

Histopathological and audiological effects of mechanical trauma associated with the placement of an intracochlear electrode, and the benefit of corticosteroid infusion: prospective animal study

2014 ◽  
Vol 128 (8) ◽  
pp. 702-708 ◽  
Author(s):  
G Malkoc ◽  
A Dalgic ◽  
M Koc ◽  
T Kandogan ◽  
S Korkmaz ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Topical Corticosteroid ◽  
Animal Study ◽  
Hair Cells ◽  
Normal Saline ◽  
Round Window ◽  
Osmotic Pump ◽  
Mechanical Trauma ◽  
Round Window Membrane ◽  
Scala Tympani

AbstractObjective:This study aimed to present the histopathological and audiological effects of mechanical trauma associated with the placement of a model electrode in the scala tympani in rats, and the effects of continuous topical corticosteroid application.Method:The study comprised three groups of rats. The round window membrane was perforated in all three groups and a model electrode was inserted in the round window. Group one received no further treatments. Groups two and three also had an intrathecal microcatheter compatible with a mini-osmotic pump inserted; in group two this was used to release normal saline and in group three the pump released 400 µg/ml dexamethasone.Results:Dexamethasone infusion given after implantation of the intracochlear model electrode was more effective for preventing hearing loss than the administration of just one dose of dexamethasone.Conclusion:The findings suggest that continuous dexamethasone infusion is beneficial for preventing the loss of hair cells and neurons associated with early and late periods of intracochlear electrode trauma.

Impact of Cochlear Implantation on Neurocognitive Subdomains in Adult Cochlear Implant Recipients

2021 ◽  
pp. 1-10
Author(s):  
Christiane Völter ◽  
Lisa Götze ◽  
Imme Haubitz ◽  
Janine Müther ◽  
Stefan Dazert ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Cochlear Implant ◽  
Cochlear Implantation ◽  
Verbal Fluency ◽  
Homogeneous Population ◽  
Delayed Recall ◽  
Hearing Status ◽  
Age Related ◽  
Significant Difference ◽  
The Impact

<b><i>Introduction:</i></b> Age-related hearing loss affects about one-third of the population worldwide. Studies suggest that hearing loss may be linked to cognitive decline and auditory rehabilitation may improve cognitive functions. So far, the data are limited, and the underlying mechanisms are not fully understood. The study aimed to analyze the impact of cochlear implantation on cognition in a large homogeneous population of hearing-impaired adults using a comprehensive non-auditory cognitive assessment with regard to normal-hearing (NH) subjects. <b><i>Material and Methods:</i></b> Seventy-one cochlear implant (CI) candidates with a postlingual, bilateral severe or profound hearing loss aged 66.3 years (standard deviation [SD] 9.2) and 105 NH subjects aged 65.96 years (SD 9.4) were enrolled. The computer-based neurocognitive tool applied included 11 subtests covering attention (M3), short- and long-term memory (recall and delayed recall), working memory (0- and 2-back, Operation Span [OSPAN] task), processing speed (Trail Making Test [TMT] A), mental flexibility (TMT B), inhibition (cFlanker and iFlanker), and verbal fluency. CI patients underwent a neurocognitive testing preoperatively as well as 12 months postoperatively. Impact of hearing status, age, gender, and education on cognitive subdomains was studied. Additionally, after controlling for education and age, cognitive performance of CI subjects (<i>n</i> = 41) was compared to that of NH (<i>n</i> = 34). <b><i>Results:</i></b> CI users achieved significantly better neurocognitive scores 12 months after cochlear implantation than before in most subtests (M3, [delayed] recall, 2-back, OSPAN, iFlanker, and verbal fluency; all <i>p</i> &#x3c; 0.05) except for the TMT A and B. A significant correlation could be found between the postoperative improvement in speech perception and in the attentional task M3 (<i>p</i> = 0.01). Hearing status (<i>p</i> = 0.0006) had the strongest effect on attention, whereas education had a high impact on recall (<i>p</i> = 0.002), OSPAN (<i>p</i> = 0.0004), and TMT A (<i>p</i> = 0.005) and B (<i>p</i> = 0.003). Inhibition was mainly age-dependent with better results in younger subjects (<i>p</i> = 0.016). Verbal fluency was predicted by gender as females outperformed men (<i>p</i> = 0.009). Even after controlling for age and education NH subjects showed a significantly better performance than CI candidates in the recall (<i>p</i> = 0.03) and delayed recall (<i>p</i> = 0.01) tasks. Postoperatively, there was no significant difference between the 2 groups anymore. <b><i>Conclusion:</i></b> Impact of cochlear implantation on neurocognitive functions differs according to the cognitive subdomains. Postoperatively, CI recipients performed as good as age- and education-matched NH subjects.

scholarly journals Cochlear Implantation Following Explorative Tympanotomy in Patients With Sudden Sensorineural Hearing Loss: Surgical Features and Audiological Outcomes

2021 ◽  
pp. 014556132110091
Author(s):  
Robin Rupp ◽  
Joachim Hornung ◽  
Matthias Balk ◽  
Matti Sievert ◽  
Sarina Müller ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Connective Tissue ◽  
Sensorineural Hearing Loss ◽  
Cochlear Implantation ◽  
Round Window ◽  
Sudden Sensorineural Hearing Loss ◽  
Sensorineural Hearing ◽  
Round Window Membrane ◽  
Hearing Results ◽  
Round Window Niche

Objective: To investigate the anatomical status of the round window niche and hearing outcome of cochlear implantation (CI) after explorative tympanotomy (ExT) with sealing of the round window membrane in patients with sudden sensorineural hearing loss at a tertiary referral medical center. Methods: Between January 1, 2007, and July 30, 2020, 1602 patients underwent CI at our department. Out of these, all patients previously treated by ExT with sealing of the round window membrane because of unilateral sudden hearing loss were included in the study. A retrospective chart review was conducted concerning method of round window membrane sealing, intraoperative findings during CI, postoperative imaging, and hearing results. Results: Twenty one patients (9 females; 8 right ears; 54.3 years [± 12.9 years]) underwent ExT with sealing of the round window membrane with subsequent CI after 26.6 months (± 32.9 mo) on average. During CI, in 76% of cases (n = 16), the round window niche was blocked by connective tissue due to the previous intervention but could be removed completely in all cases. The connective tissue itself and its removal had no detrimental effects on the round window membrane. Postoperative computed tomography scan showed no electrode dislocation. Mean postoperative word recognition score after 3 months was 57.4% (± 17.2%) and improved significantly to 73.1% (± 16.4%, P = .005) after 2 years. Conclusion: Performing CI after preceding ExT, connective tissue has to be expected blocking the round window niche. Remaining tissue can be removed safely and does not alter the round window membrane allowing for a proper electrode insertion. Short- and long-term hearing results are satisfactory. Consequently, ExT with sealing of the round window membrane in patients with sudden sensorineural hearing loss does not impede subsequent CI that can still be performed safely.

Direct drug application to the round window: A comparative study of ototoxicity in rats

2009 ◽  
Vol 141 (5) ◽  
pp. 584-590 ◽  
Author(s):  
Silvia Murillo-Cuesta ◽  
Fernando García-Alcántara ◽  
Elena Vacas ◽  
Jon Alexander Sistiaga ◽  
Guadalupe Camarero ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Cell Damage ◽  
Round Window ◽  
Drug Application ◽  
Local Drug Delivery ◽  
Saline Control ◽  
Round Window Membrane ◽  
Cochlear Function ◽  
Profound Hearing Loss ◽  
Brainstem Response

Objective: To assess the validity of inducing ototoxicity in rats by applying a sponge soaked in kanamycin and furosemide on the round window. Study Design: Basic, randomized, nonblind experimental study. Setting: Animal models of cochlear damage and reliable methods of local drug delivery are fundamental to study hearing loss and to design new therapies. Subjects and Methods: Four experimental groups of six Wistar rats with different methods of drug administration were used: (1) injection of subcutaneous kanamycin (400 mg/kg) and intravenous furosemide (100 mg/kg); (2) local application of a sponge soaked in saline close to the round window; (3) animals for which the sponge was soaked in a solution containing kanamycin (200 mg/mL) and furosemide (50 mg/mL); and (4) sham-operated rats. The tympanic bulla was exposed using a ventral approach, and a bullostomy was performed to visualize the round window membrane. Cochlear function was assessed by measuring the auditory brainstem response, and hearing thresholds in response to click and tone burst stimuli were determined as peak and interpeak latencies. At the end of the study, cochlear histology was analyzed. Results: Systemic administration of kanamycin and furosemide induced profound hearing loss and severe hair cell damage. Local delivery of these ototoxic drugs caused comparable damage but avoided the systemic side effects of the drug. Sham-operated and saline control animals did not experience functional alterations. Conclusion: Situating a sponge soaked in kanamycin and furosemide on the round window membrane through the ventral approach is a reliable method to provoke local ototoxicity in rats.

scholarly journals The Protective Effect of Intratympanic Dexamethasone on Streptomycin Ototoxicity in Rats

2017 ◽  
Vol 96 (6) ◽  
pp. E12-E17 ◽  
Author(s):  
Aylin Göl ◽  
Engin Şengül ◽  
Beyhan Yılmaz ◽  
Fazıl Emre Özkurt ◽  
Mehmet Akdağ ◽  
...  
Keyword(s):  
Experimental Study ◽  
Hair Cells ◽  
Otoacoustic Emissions ◽  
Albino Rats ◽  
Protective Effects ◽  
Cochlear Hair Cells ◽  
Distortion Product ◽  
Dexamethasone Group ◽  
Significant Difference ◽  
Intratympanic Dexamethasone

The purpose of this experimental study was to investigate the protective role of intratympanically administered dexamethasone on the inner ears of rats that were exposed to streptomycin ototoxicity. Twenty-four adult Wistar albino rats were separated into 4 groups: Group 1 (only streptomycin), Group 2 (only intratympanic dexamethasone), Group 3 (streptomycin and intratympanic dexamethasone), and Group 4 (streptomycin and intratympanic saline). All rats were evaluated with distortion product otoacoustic emissions (DPOAE) tests before the start of treatment and on the day it ended. On the 45th day, after the final DPOAE tests, animals of all groups were sacrificed under general anesthesia. The differences between the amplitudes of DPOAE results were determined, and hearing results were statistically analyzed. Also, the cochleas of each rat were histopathologically evaluated under a light microscope with hematoxylin and eosin staining. In the intratympanic dexamethasone group it was observed that cochlear hair cells were mostly protected. No significant difference was seen between the DPOAE results before and after treatment (p > 0.05). On the other hand, loss was observed in the hearing functions and hair cells of the rats that received streptomycin and streptomycin plus intratympanic saline (p < 0.05). In the streptomycin plus intratympanic dexamethasone group, the cochlear hair cells were partially protected. A significant difference was observed when the DPOAE results (DP-grams) of the streptomycin plus intratypmanic dexamethasone group were compared to those of the streptomycin plus intratympanic saline group (p < 0.05). After the experimental study, ototoxic effects of the administration of streptomycin and intratympanic dexamethasone were observed on the rats’ cochlear hair cells. We conclude that intratympanic dexamethasone has protective effects against this cochlear damage in rats.

scholarly journals Preoperative Evaluation and Surgical Outcome of Cochlear Implantation in NIENT

2020 ◽  
Vol 26 (2) ◽  
pp. 128-135
Author(s):  
Md Zakaria Sarker ◽  
Muhammad Rafiqul Islam ◽  
Utpal Kumar Dutta ◽  
Debabrota Roy ◽  
AHM Ferdows Nur ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Facial Nerve ◽  
Psychosocial Development ◽  
Cochlear Implantation ◽  
Preoperative Evaluation ◽  
Round Window ◽  
Round Window Membrane ◽  
Safe Procedure ◽  
Female Ratio ◽  
Facial Recess

Background: Sensory neural hearing loss (SNHL) is the most common congenital sensory deficit, with an incidence of one to three per 1000 live births. Acoustic deprivation during the first 3 years of life can hinder speech and language acquisition with significant negative consequences on a child’s educational and psychosocial development. The gold standard intervention for permanent severe to profound hearing loss is cochlear implantation. Cochlear implant (CI); is a semi implantable electronic device that bypass the cochlea. Objectives: An observational study was carried out on 40 cases of pre-lingual deaf to find out the causes of pre-lingual deaf, to evaluate the preoperative procedures to set ideal criteria for pre -lingual cochlear implantation and to evaluate surgical procedure and outcome of cochlear implantations. Methods: Evaluation of the candidates included patient medical history, general health checkup, ENT examination, audiometric evaluation, CT and MRI scans, psychological profile of the candidate. A limited cortical mastoidectomy was performed. The facial recess was opened using the fossa of incudis as an initial landmark. The round window niche was visualized through the facial recess about 2 mm inferior to the stapes. A cochleostomy created by drilling over the basal turn of the cochlea anterior and inferior to the annulus of the round window membrane. The electrode array was then carefully inserted through the fenestra into the scala tympani of the cochlea. Electrophysiological testing (Neural Response Telemetry: NRT) was performed to verify the correct placement of active electrodes. Resulst: Among them 22 (55%) were male and 18 (45%) were female. Male female ratio was 1.2:1. Age distribution at implantation was 3.3±1.054(SD). Average hearing loss was 96.4±5.3(SD) dB and in aided audiogram was 63.7±4.6(SD) dB. Overall complications occurred in 10 (25%) cases. Transient facial nerve paresis in 2 (5%), injury of tympanic membrane in 1(2.5%), seroma 4(10%) and delayed otitis media in 1(2.5%) were observed. Major postoperative complications occurred in 2 cases including facial nerve palsy in 1(2.5%) case and spontaneous device failure in 1(2.5%) case. Conclusion: The result of this survey was find out the risk factor of congenital hearing loss. With a thorough preoperative evaluation, we can select proper candidates for CI which is a reliable and safe procedure with a low percentage of severe complication. Bangladesh J Otorhinolaryngol; October 2020; 26(2): 128-135

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