Auditory Nerve Research Articles

Sudden sensorineural hearing loss during pregnancy. A case study and literature review

<b>Introduction:</b> Sudden sensorineural hearing loss (SSNHL) is defined as the sudden onset of hearing loss of 30 dB or more, across three consecutive frequencies in a pure-tone audiogram occurring within a 72-hour period. The term “sensorineural” indicates that the cause of the hearing loss lies in disturbances within the cochlea or auditory nerve. SSNHL typically presents as unilateral, transient hearing loss that occurs upon awakening. Bilateral hearing loss occurs in less than 2% of patients. Additionally, patients may report sensations of ear fullness or blockage, tinnitus, dizziness, nausea, and vomiting.<b>Aim:</b> Defining the management of SSNHL in pregnant women.<b>Case report:</b> This article describes the case of a 36-years-old pregnant woman who developed hearing impairment in the left ear in the third trimester along with tinnitus and balance disorders.<b>Discussion:</b> The occurrence of SSNHL in pregnant women is rare and not well understood. Majority of pregnant patients with SSNHL experienced the condition in second or third trimester. Key elements facilitating an accurate diagnosis include: interview and physical examination, hearing tests, balance evaluation, and imaging studies. The exact causes of SSNHL in pregnant women remain unknown. However, hormonal changes during pregnancy can have some contribution to development of this condition. Onset of SSNHL symptoms could resemble Ménière’s disease.<b>Conclusions:</b> Due to rare occurrence of SSNHL in pregnant women, there is no standardized approach to managing this medical issue. Given that most cases of SSNHL are classified as idiopathic, empirical treatment primarily involves steroids.

Toward Optogenetic Hearing Restoration.

The cochlear implant (CI) is considered the most successful neuroprosthesis as it enables speech comprehension in the majority of the million otherwise deaf patients. In hearing by electrical stimulation of the auditory nerve, the broad spread of current from each electrode acts as a bottleneck that limits the transfer of sound frequency information. Hence, there remains a major unmet medical need for improving the quality of hearing with CIs. Recently, optogenetic stimulation of the cochlea has been suggested as an alternative approach for hearing restoration. Cochlear optogenetics promises to transfer more sound frequency information, hence improving hearing, as light can conveniently be confined in space to activate the auditory nerve within smaller tonotopic ranges. In this review, we discuss the latest experimental and technological developments of optogenetic hearing restoration and outline remaining challenges en route to clinical translation.

Simultaneous cochlear implantation with early endoscopic surgery in small acoustic neuroma.

The exclusive endoscopic transcanal transpromontorial approach (EETTA) has recently been developed for the removal of small-sized acoustic neuromas in the labyrinth (intralabyrinthine schwannoma [ILS]) or internal auditory canal (IAC). Although small tumors that meet the indications for EETTA are also good candidates for cochlear implantation (CI), there are few reports on CI after schwannoma removal using EETTA. Here we present an outcome of patients who underwent simultaneous EETTA and CI. Five patients (two with IAC fundus tumors and three with ILS) who underwent simultaneous EETTA and CI between 2020 and 2022 were retrospectively enrolled. Their medical charts and test results were reviewed. After at least 12 months of follow-up, there were no severe surgical complications such as meningitis, infection, or skin necrosis. Four of the five patients responded to auditory stimulation. Three out of four auditory-responsive patients scored >80% on sentence recognition. Simultaneous EETTA and CI are feasible for the treatment of ILS and IAC fundus tumors. Preservation of the cochlear nerve and modiolus is important for favorable CI outcomes. Therefore, ILS and IAC fundus tumors in patients with nonserviceable hearing should be surgically removed as early as possible to enable proper hearing rehabilitation with CI. Level 4.

Elevated modiolus density on high-resolution computed tomography as an indicator of cochlear neurodysplasia: a retrospective case-control study.

Cochlear neurodysplasia (CND) is recognized as a contributing factor to sensorineural hearing loss in children. This study aimed to investigate the relationship between modiolus density on high-resolution computed tomography (HRCT) and CND, and to evaluate its performance in diagnosing CND. This retrospective study collected HRCT images of 34 patients diagnosed with unilateral neurological hearing loss in the Children's Hospital of Chongqing Medical University from March 2018 to December 2023, who were also diagnosed with unilateral CND by computed tomography (CT) and magnetic resonance imaging (MRI) hydroimaging. CT values of the modiolus and petrous bone were measured on the affected and healthy sides, in addition to determining the width of cochlear nerve foramina and the width of internal auditory tract. The receiver operator characteristic (ROC) curve was used to evaluate the diagnostic performance of these features. Simultaneously, comparisons were conducted with parameters obtained from normal children. A total of 29 patients without CND were randomly selected as a control group. The unilateral sensorineural hearing loss group had 34 patients, comprising 18 males and 16 females, with a median age of 4.5 years, ranging from 0.7 to 11 years. The normal children group consisted of 20 males and 9 females, with a median age of 5.9 years, ranging from 0.5 to 12.0 years. Statistically significant differences were observed in the CT values of the modiolus, modiolus/petrous bone CT value ratio, width of cochlear nerve foramina, and width of internal auditory tract between the affected and healthy sides in patients with unilateral sensorineural hearing loss (P<0.05). The area under the ROC curve (AUC) of the modiolus CT value and the width of cochlear nerve foramina for the diagnosis of unilateral sensorineural hearing loss was 0.98 [95% confidence interval (CI): 0.95-1.00] and 0.99 (95% CI: 0.98-1.00), respectively. the modiolus density was significantly elevated in the affected sides in patients with unilateral CND. The optimal cut-off value of modiolus CT values was 983 Hounsfield unit (HU). The elevated density of the modiolus on HRCT holds significant value in diagnosing CND.

Effects of Age on Responses of Principal Cells of the Mouse Anteroventral Cochlear Nucleus in Quiet and Noise.

Older listeners often report difficulties understanding speech in noisy environments. It is important to identify where in the auditory pathway hearing-in-noise deficits arise to develop appropriate therapies. We tested how encoding of sounds is affected by masking noise at early stages of the auditory pathway by recording responses of principal cells in the anteroventral cochlear nucleus (AVCN) of aging CBA/CaJ and C57BL/6J mice in vivo. Previous work indicated that masking noise shifts the dynamic range of single auditory nerve fibers (ANFs), leading to elevated tone thresholds. We hypothesized that such threshold shifts could contribute to increased hearing-in-noise deficits with age if susceptibility to masking increased in AVCN units. We tested this by recording the responses of AVCN principal neurons to tones in the presence and absence of masking noise. Surprisingly, we found that masker-induced threshold shifts decreased with age in primary-like units and did not change in choppers. In addition, spontaneous activity decreased in primary-like and chopper units of old mice, with no change in dynamic range or tuning precision. In C57 mice, which undergo early-onset hearing loss, units showed similar changes in threshold and spontaneous rate at younger ages, suggesting they were related to hearing loss and not simply aging. These findings suggest that sound information carried by AVCN principal cells remains largely unchanged with age. Therefore, hearing-in-noise deficits may result from other changes during aging, such as distorted across-channel input from the cochlea and changes in sound coding at later stages of the auditory pathway.

Gene Electrotransfer via Conductivity-Clamped Electric Field Focusing Pivots Sensori-Motor DNA Therapeutics: "A Spoonful of Sugar Helps the Medicine Go Down".

Viral vectors and lipofection-based gene therapies have dispersion-dependent transduction/transfection profiles that thwart precise targeting. The study describes the development of focused close-field gene electrotransfer (GET) technology, refining spatial control of gene expression. Integration of fluidics for precise delivery of "naked" plasmid deoxyribonucleic acid (DNA)in sucrose carrier within the focused electric field enables negative biasing of near-field conductivity ("conductivity-clamping"-CC), increasing the efficiency of plasma membrane molecular translocation. This enables titratable gene delivery with unprecedently low charge transfer. The clinic-ready bionics-derived CC-GET device achieved neurotrophin-encoding miniplasmid DNA delivery to the cochlea to promote auditory nerve regeneration; validated in deafened guinea pig and cat models, leading to improved central auditory tuning with bionics-based hearing. The performance of CC-GET is evaluated in the brain, an organ problematic for pulsed electric field-based plasmid DNA delivery, due to high required currents causing Joule-heating and damaging electroporation. Here CC-GET enables safe precision targeting of gene expression. In the guinea pig, reporter expression is enabled in physiologically critical brainstem regions, and in the striatum (globus pallidus region) delivery of a red-shifted channelrhodopsin and a genetically-encoded Ca2+sensor, achieved photoactivated neuromodulation relevant to the treatment of Parkinson's Disease and other focal brain disorders.

Do auditory brainstem implants favor the development of sensory integration and cognitive functions?

Information about the development of cognitive skills and the effect of sensory integration in children using auditory brainstem implants (ABIs) is still limited. This study primarily aims to investigate the relationship between sensory processing skills and attention and memory abilities in children with ABI, and secondarily aims to examine the effects of implant duration on sensory processing and cognitive skills in these children. The study included 25 children between the ages of 6 and 10 years (mean age: 14 girls and 11 boys) with inner ear and/or auditory nerve anomalies using auditory brainstem implants. Visual-Aural Digit Span Test B, Marking Test, Dunn Sensory Profile Questionnaire were applied to all children. The sensory processing skills of children are statistically significant and positive, and moderately related to their cognitive skills. As the duration of implant use increases, better attention and memory performances have been observed (p<.05). The study demonstrated the positive impact of sensory processing on the development of memory and attention skills in children with ABI. It will contribute to evaluating the effectiveness of attention, memory, and sensory integration skills, and aiding in the development of more effective educational strategies for these children.

Auditory nerve fiber excitability for alternative electrode placement in the obstructed human cochlea: electrode insertion in scala vestibuli versus scala tympani

Objective. The cochlear implant (CI) belongs to the most successful neuro-prostheses. Traditionally, the stimulating electrode arrays are inserted into the scala tympani (ST), the lower cochlear cavity, which enables simple surgical access. However, often deep insertion is blocked, e.g. by ossification, and the auditory nerve fibers (ANFs) of lower frequency regions cannot be stimulated causing severe restrictions in speech understanding. As an alternative, the CI can be inserted into the scala vestibuli (SV), the other upper cochlear cavity. Approach. In this computational study, the excitability of 25 ANFs are compared for stimulation with ST and SV implants. We employed a 3-dimensional realistic human cochlear model with lateral wall electrodes based on a μ-CT dataset and manually traced fibers. A finite element approach in combination with a compartment model of a spiral ganglion cell was used to simulate monophasic stimulation with anodic (ANO) and cathodic (CAT) pulses of 50 μs. Main results. ANO thresholds are lower in ST (mean/std = μ/σ = 189/55 μA) stimulation compared to SV (μ/σ = 323/119 μA) stimulation. Contrary, CAT thresholds are higher for the ST array (μ/σ = 165/42 μA) compared to the SV array (μ/σ = 122/46 μA). The threshold amplitude depends on the specific fiber-electrode spatial relationship, such as lateral distance from the cochlear axis, the angle between electrode and target ANF, and the curvature of the peripheral process. For CAT stimulation the SV electrodes show a higher selectivity leading to less cross-stimulation of additional fibers from different cochlear areas. Significance. We present a first simulation study with a human cochlear model that investigates an additional CI placement into the SV and its impact on the excitation behavior. Results predict comparable outcomes to ST electrodes which confirms that SV implantation might be an alternative for patients with a highly obstructed ST.

ICU Management of Post-Craniotomy Patients with Schwannoma Vestibular Tumor Removal

Background: Vestibular schwannoma (VS) is a relatively common tumor that arises from the vestibulocochlear nerve (CN VIII) and represents 80% of cerebellopontine angle (CPA) masses. CPA tumors are mostly benign, slow growing with low malignant potential (~1%). VS have rarely been reported, and there is a lack of in-depth discussion on the experience of management of massive acoustic neuromas in ICU. It represents the case in which the patient presented with obstructive hydrocephalus and progressive neurological deficits. The purpose of this case report is to understand the management of post-operative patients with VS with several comorbidities in the ICU.Case: We present a 53 years old woman with a giant VS and obstructive hydrocephalus. An imaging findings revealed a brain tumor in the CPA region and obstructive hydrocephalus. Consequently, she relieved her hydrocephalus with a ventriculoperitoneal shunt (VP shunt). After 1.5 years, her mental condition deteriorated, and her left limb muscle strength gradually decreased. Under a joint consultation with Department of Neurosurgery and Anesthesiology, she underwent tumor removal. Upon discharge, the previously observed neurological deficits, which were reversible had been successfully resolved. The neuroimaging confirmed the complete tumor removal, while the neuropathologic examination revealed a VS.Discussion: If untreated, an acoustic neuroma can grow large enough to cause pressure on the brain stem. The tumor can block the flow of cerebrospinal fluid (CSF) between the brain and the spinal cord, causing a buildup of the fluid in the brain. Because the skull is a closed structure, excess fluid in the brain (hydrocephalus) can press against the brain, causing unsteady movement and lack of coordination (ataxia), headaches and confusion. Patients with brainstem compression had significantly longer mean LOS than patients without. Also, the dissection of the facial nerve from the tumor in order to preserve it can sometimes cause swelling, which can result in weakness or paralysis (complete or partial loss of muscle function). This is usually temporary but can take weeks to months to recover. After the operation, the patient was treated in the ICU, a ventilator was installed,insulin was given to regulate blood sugar and anti-hypertension medication for maintaining blood pressure. During treatment in the ICU, adequate fluids and nutrition are provided. Monitoring is carried out on cardiovascular function, hemodynamics and respiration by monitoring blood pressure, electrocardiogram (ECG), oxygen saturation. The patient was moved to high care unit (HCU) after being treated for 3 days in the ICU.Conclusion: Postoperative therapy is more focused on supportive therapy, including maintaining the airway, regulating blood sugar, blood pressure and providing mechanical ventilation to maintain adequate oxygenation.

Wireless electrocochleography in awake chinchillas: A model to study crossmodal modulations at the peripheral level

The discovery and development of electrocochleography (ECochG) in animal models has been fundamental for its implementation in clinical audiology and neurotology. In our laboratory, the use of round-window ECochG recordings in chinchillas has allowed a better understanding of auditory efferent functioning. In previous works, we gave evidence of the corticofugal modulation of auditory-nerve and cochlear responses during visual attention and working memory. However, whether these cognitive top-down mechanisms to the most peripheral structures of the auditory pathway are also active during audiovisual crossmodal stimulation is unknown. Here, we introduce a new technique, wireless ECochG to record compound-action potentials of the auditory nerve (CAP), cochlear microphonics (CM), and round-window noise (RWN) in awake chinchillas during a paradigm of crossmodal (visual and auditory) stimulation. We compared ECochG data obtained from four awake chinchillas recorded with a wireless ECochG system with wired ECochG recordings from six anesthetized animals. Although ECochG experiments with the wireless system had a lower signal-to-noise ratio than wired recordings, their quality was sufficient to compare ECochG potentials in awake crossmodal conditions. We found non-significant differences in CAP and CM amplitudes in response to audiovisual stimulation compared to auditory stimulation alone (clicks and tones). On the other hand, spontaneous auditory-nerve activity (RWN) was modulated by visual crossmodal stimulation, suggesting that visual crossmodal simulation can modulate spontaneous but not evoked auditory-nerve activity. However, given the limited sample of 10 animals (4 wireless and 6 wired), these results should be interpreted cautiously. Future experiments are required to substantiate these conclusions. In addition, we introduce the use of wireless ECochG in animal models as a useful tool for translational research.

A preoperative dose of the pyridoindole AC102 improves the recovery of residual hearing in a gerbil animal model of cochlear implantation

Sensorineural hearing loss (SNHL) is the most common sensory deficit worldwide. Due to the heterogeneity of causes for SNHL, effective treatment options remain scarce, creating an unmet need for novel drugs in the field of otology. Cochlear implantation (CI) currently is the only established method to restore hearing function in profound SNHL and deaf patients. The cochlear implant bypasses the non-functioning sensory hair cells (HCs) and electrically stimulates the neurons of the cochlear nerve. CI also benefits patients with residual hearing by combined electrical and auditory stimulation. However, the insertion of an electrode array into the cochlea induces an inflammatory response, characterized by the expression of pro-inflammatory cytokines, upregulation of reactive oxygen species, and apoptosis and necrosis of HCs, putting residual hearing at risk. Here, we characterize the small molecule AC102, a pyridoindole, for its protective effects on residual hearing in CI. In a gerbil animal model of CI, AC102 significantly improves the recovery of hearing thresholds across multiple frequencies and confines the cochlear trauma to the directly mechanically injured area. In addition, AC102 significantly preserves auditory nerve fibers and inner HC synapses throughout the whole cochlea. In vitro experiments in an ethanol challenged HT22 cell-line revealed significant and dose-responsive anti-apoptotic effects following the treatment of with AC102. Further, AC102 treatment resulted in significant downregulation of the expression of pro-inflammatory cytokines in an organotypic ex vivo model of electrode insertion trauma (EIT). These results suggest that AC102’s effects are likely elicited during the inflammatory phase of EIT and mediated by anti-apoptotic and anti-inflammatory properties, highlighting AC102 as a promising compound for hearing preservation during CI. Moreover, since the inflammatory response in CI shares similarities to that in other etiologies of SNHL, AC102 may be inferred as a potential general treatment option for various inner ear conditions.

“Correlation between cochlear nerve size and outcome of cochlear implant "

“Correlation between cochlear nerve size and outcome of cochlear implant "

Long-Term Hearing Outcome For Vestibular Schwannomas After Microsurgery And Radiotherapy: A Systematic Review and Meta-Analysis.

Hearing loss is a common symptom associated with vestibular schwannoma (VS), either because of the tumor's effects on the cochlear nerve or due to active treatments such as surgery or stereotactic radiosurgery (SRS). Treatment decisions for VS are based on factors including tumor size, hearing status, patient symptoms, and institutional preference. The study aimed to investigate long-term auditory outcomes in VS patients undergoing active treatments with a hearing preservation intent. A systematic literature review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, searching Scopus, Pubmed, and Web of Science databases from inception to January 2024. Studies meeting inclusion criteria, including a minimum 5-year follow-up and assessment of pre- and posttreatment hearing outcomes, were included. Pooled prevalence estimates for serviceable hearing after SRS and microsurgery were calculated using MetaXL software. Risk of bias assessment was performed with the Risk of Bias in Non-randomized Studies of Interventions tool. Nine studies met the inclusion criteria, with 356 patients included for analysis. The pooled prevalence of maintaining serviceable hearing after SRS at 10 years was 18.1% (95% confidence interval [CI]: 1.7%-43.3%), with wide prediction intervals indicating variability in outcomes. Microsurgery demonstrated a higher prevalence of maintaining long-term serviceable hearing, with a pooled estimate of 74.5% (95% CI: 63.5%-84.1%). This systematic review underscores the importance of long-term follow-up in evaluating auditory outcomes in VS treatment. Despite the biases inherent to pretreatment patients selection, hearing preservation microsurgery for sporadic VS removal demonstrated favorable and stable long-term serviceable hearing.

Assessing Neural Synchrony in the Cochlear Nerve to Electrical Stimulation in Children With Auditory Neuropathy Spectrum Disorder.

This study reported phase locking values (PLVs) that quantified the trial-to-trial phase coherence of electrically evoked compound action potentials in children with auditory neuropathy spectrum disorders (ANSD) and children with Gap Junction Beta 2 (GJB2) mutations, a patient population without noticeable cochlear nerve damage. PLVs were measured at three electrode locations in 11 children with ANSD and 11 children with GJB2 mutations. Smaller PLVs indicated poorer neural synchrony. A linear mixed-effects model was used to compare PLVs measured at different electrode locations between participant groups. After controlling for the stimulation level effect, children with ANSD had smaller PLVs than children with GJB2 mutations at all three electrode locations. Cochlear-implanted children with ANSD show poorer peripheral neural synchrony than children with GJB2 mutations.

Single-Sided Deafness (SSD) - With the "Second" You Hear Better

Single-sided deafness (SSD) is characterised by deafness in one ear while the other ear has normal hearing. The most common cause in congenital SSD is aplasia of the auditory nerve, and in post-lingual SSD idiopathic hearing loss. Patients with SSD mainly suffer from impaired sound localisation and difficulties in speech perception in noise. There are various therapy options, but binaural hearing is only possible with a cochlear implant (CI).

Subtotal resection of vestibular schwannoma with subsequent Gamma Knife irradiation - tumor growth control, facial and cochlear nerve outcome - preliminary results.

&lt;b&gt;Introduction:&lt;/b&gt; The choice of treatment of vestibular schwannoma (VS) depends on several factors, including the tumor size, the patient's age and overall health, and the presence and severity of symptoms.&lt;b&gt;Aim:&lt;/b&gt; The aim of the study was to assess the effectiveness of intentional subtotal resection (STR) of tumor followed by Gamma Knife surgery (GKS) in patients with larger VS (Koos 3 and 4).&lt;b&gt;Materials and methods:&lt;/b&gt; The retrospective analysis was performed on 18 patients. Data of VS volumes measured in MRI, the facial nerve function assessed in the House-Brackmann scoring system (HB), and the results of audiological examination expressed on the Gardner-Robertson scale (GR) were collected preoperatively, postoperatively, and post-GKS.&lt;b&gt;Results:&lt;/b&gt; Preoperatively, the main symptom was hearing loss observed in 13 out of 18 patients. The facial nerve function was assessed as HB 1 in 16, whereas HB 2 in 2 patients. The mean volume of the tumor in the initial MRI amounted to 16.81 cm&lt;sup&gt;3&lt;/sup&gt; . Postoperatively, the facial nerve was assessed as HB 1 or 2 in 16, whereas HB 3 in 2 patients. Serviceable hearing was presented by only 4 persons. The Mean diameter of the tumor after subtotal surgery amounted to 3.16 cm&lt;sup&gt;3&lt;/sup&gt; , 1.83 cm&lt;sup&gt;3&lt;/sup&gt; after GKS, and 1.58 cm&lt;sup&gt;3&lt;/sup&gt; at the last follow-up. The facial nerve function and hearing level remained the same as before GKS in all patients.&lt;b&gt;Conclusions:&lt;/b&gt; STR followed by GKS can be a safe and effective method of treatment of large VS concerning the functional outcome of the facial nerve and the tumor volume growth control.

Cochlear reimplantation outcomes over 20 years: Expertise in reimplantation surgery and auditory-speech rehabilitation

ObjectivesThe aim of this study was to present an institution's experience with cochlear reimplantation (CRI), to assess surgical challenges and post-operative outcomes and to increase the success rate of CRI. Study designRetrospective single-institution study. SettingTertiary medical center. MethodsWe retrospectively evaluated data from 76 reimplantation cases treated in a tertiary center between 2001 and 2022. Clinical features including etiology of hearing loss, type of failure, surgical issues, and auditory speech performance were analyzed. Categorical Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) scores were used to evaluate pre- and post-CRI outcomes. ResultsThe CRI population comprises of 7 patients from our institute,69 referred patients from other centers. Device failure was the most common reason (68/76, 89.5 %) for CRI; in addition, there were 7 medical failures and 1 had both soft device failure. Medical failures included flap rupture and device extrusion, magnet migration, auditory neuropathy, leukoencephalopathy, foreign-body residue and meningitis. In 21/76 patients, the electrode technology was upgraded. The mean time to failure was 0.58–13 years, with a mean of 4.97 years. The mean (± SD) CAP and SIR scores before and after CRI were 5.2 ± 1.2 versus 5.5 ± 1.1 and 3.4 ± 1.1 versus 3.5 ± 1.1, respectively. Performance was poor in six patients with severe cochlear malformation, auditory nerve dysplasia, leukoencephalopathy, and epilepsy. ConclusionCRI surgery is a challenging but relatively safe procedure, and most reimplanted patients experience favorable postoperative outcomes. Medical complications and intracochlear damage are the main causes of poor postoperative results. Therefore, adequate preoperative preparation and atraumatic CRI should be carried out for optimal results.

Efficacy of cochlear implantation in cochlear nerve deficiency children – A single center study

PurposesThe objective of this research was to interpret and analyze the imaging, audiological features and cochlear implantation outcomes in cochlear nerve deficiency children. Material and methodsRetrospective analysis. Results25 prelingual hearing loss children diagnosed cochlear nerve deficiency (CND), the age range from 1 to 15 (mean age, 5.04), underwent cochlear implantation at Ear Nose and Throat Hospital - Ho Chi Minh City (ENT hospital – HCMC) from 2016 to 2023. All children had sensorineural hearing loss (SNHL) from severe to profound degree. Magnetic resonance imaging (MRI) showed cochlear nerve hypoplasia in 76 % and cochlear nerve aplasia in 24 % of cases. Inner ear malformations were found in 52 % of cases. The mean Categories of Auditory Performance (CAP) score at 1 year after surgery was 4.8. At 6 months and 1 year after surgery, the mean CAP score of the aplasia group was significantly lower than that of the hypoplasia group (p < 0.05). ConclusionsIn cochlear nerve deficiency children, auditory perception and speech performance still improved after cochlear implantation. However, this progress was significantly limited in cochlear nerve aplasia group.

Intraoperative Hearing Monitoring Using ABR and TT-ECochG and Hearing Preservation during Vestibular Schwannoma Resection.

Background: Quick and appropriate diagnostics and the use of intraoperative monitoring (IM) of hearing during vestibular schwannoma (VS) resection increase the likelihood of hearing preservation. During surgery, various methods of IM can be used, i.e., auditory brainstem responses (ABRs), transtympanic electrocochleography (TT-ECochG), and direct cochlear nerve action potentials. The aim of the study was to evaluate the prognostic values of IM of hearing using ABR and TT-ECochG in predicting postoperative hearing preservation and to evaluate relationships between them during various stages of surgery. Methods: This retrospective study presents the pre- and postoperative audiological test results and IM of hearing records (TT-ECochG and ABR) in 75 (43 women, 32 men, aged 18-69) patients with diagnosed VS. Results: The preoperative pure tone average hearing threshold was 25.02 dB HL, while after VS resection, it worsened on average by 30.03 dB HL. According to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) Hearing Classification, before and after (pre/post) surgery, there were 47/24 patients in hearing class A, 9/8 in B, 2/1 in C, and 17/42 in D. In speech audiometry, the average preoperative speech discrimination score at an intensity of 60 dB SPL was 70.93%, and after VS resection, it worsened to 38.93%. The analysis of electrophysiological tests showed that before the tumor removal the I-V ABR interlatencies was 5.06 ms, and after VS resection, it was 6.43 ms. Conclusions: The study revealed correlations between worse postoperative hearing and changes in intraoperatively measured ABR and TT-ECochG. IM of hearing is very useful in predicting postoperative hearing in VS patients and increases the chance of postoperative hearing preservation in these patients.

Intra-operative test electrode and electrical auditory brainstem response prior to cochlear implantation in CHARGE syndrome

Assessing auditory nerve excitability is crucial in determining candidacy for Cochlear Implantation (CI). Pre-operative tests, such as Electrical Auditory Brainstem Response (EABR), are utilized to evaluate the function of the auditory pathway.