Internal Auditory Canal Research Articles

Application of two kinds of electrophysiological monitoring techniques for the prediction of facial nerve outcomes after vestibular Schwannoma surgery

Objective: To investigate the application of transcranial facial nerve motor evoked potential (FNMEP) and direct nerve electrical stimulation (DNES) for the prediction of facial nerve function after vestibular schwannoma surgery. Methods: The clinical data of 106 patients who underwent vestibular schwannoma surgery under electrophysiological monitoring of facial nerve between 2017 and 2021 were retrospectively examined, and there were 57 males and 49 females, with a mean age of (51±11) years. Neuroelectrophysiological monitoring was performed in all patients during the operation. After the tumor was removed, FNMEP and DNES were used for electrophysiological evaluation of facial nerve function. The amplitude ratios of FNMEP to baseline (M1) and the brainstem segment to the internal auditory canal segment of DNES (M2) were recorded after the tumor was removed, respectively. The correlation between these two ratios and facial nerve function at 1 day, 1 month and 3 months after the operation were compared. According to the House-Brackmann (HB) scale, Grade Ⅰ-Ⅱ refers to good facial nerve function, and grade Ⅲ-Ⅵ refers to moderate and severe facial nerve dysfunction. Non-parameter Spearman correlation coefficient was used to evaluate the correlation between M1 and M2 and facial nerve function at 1 day, 1 month and 3 months after operation, and the receiver operating characteristic (ROC) curves were plotted to verify the diagnostic efficacy of M1 and M2 for predicting the prognosis of postoperative facial nerve function. Results: Among 106 patients, 102 cases (96.3%) underwent total tumor resection, 4 patients (3.7%) underwent subtotal resection, 104 patients (98.1%) had anatomical preservation of facial nerves, and there were no deaths reported. All patients could evoke reliable FNMEP and 2 patients could not evoke DNES in the brainstem segment of the facial nerve. There were 81 (76.4%), 99 (93.4%) and 103 patients (97.2%) with satisfactory function of facial nerve at 1 day, 1 month and 3 months after surgery, respectively. M1 had large absolute values of Spearman correlation coefficient at 1 day (ρ=|-0.648|) and 1 month (ρ=|-0.552|) after surgery (both P<0.001), while M2 showed a greater absolute value of Spearman correlation coefficient at 3 months (ρ=|-0.395|) than that of M1 (ρ=|-0.378|) (P<0.001). Cut-off value of M1 was 0.58 (sensitivity=0.92, specificity=0.64), and that of M2 was 0.36 (sensitivity=0.64, specificity=1.00). Meanwhile, M1<0.58 or M2<0.36 suggested moderate and severe impairment of facial nerve function. Conclusions: Both FNMEP and DNES during vestibular schwannoma surgery can effectively evaluate the postoperative facial nerve function. FNMEP is better than DNES in predicting the early postoperative facial nerve function, but DNES is better for predicting the long-term postoperative facial nerve function.

Intracranial squamous cell carcinoma of the cerebello-pontine angle mimicking a cystic acoustic schwannoma. A case report with discussion of differential diagnosis and review of literature

We report a case of a primary intracranial squamous cell carcinoma (SCC) of the cerebello-pontine angle extending through the internal auditory canal, with the unusual presentation of a completely cystic lesion with no diffusion restriction, internal necrotic-hemorrhagic changes and peripheral enhancement, mimicking a cystic acoustic schwannoma. The lack of diffusion restriction and the peripheral enhancement along the lesion, 2 unique findings, supposedly reflected complete cancerization of the epidermoid cyst from which the SCC originated. We discuss the differential diagnosis and review the literature on primary intracranial SCC.

Assessment of the distribution and volume of air chambers around the inner auditory canal on high-resolution computed tomography scans of the temporal bone.

Assessment of the distribution and volume of air chambers around the inner auditory canal on high-resolution computed tomography scans of the temporal bone.

Osteoma of the Internal Auditory Canal as a Rare Finding in Imaging: A Case Report

Osteomas are a type of benign tumors that can develop in various bones of the skull. The fronto-ethmoidal region is the most commonly affected site, with over 50% of cases being reported in this location. The temporal bone, particularly the mastoid and external auditory canal regions, is another frequent site of osteoma formation. However, the occurrence of osteomas within the middle ear is relatively uncommon. The presence of osteomas within the internal auditory canal is a rare phenomenon and has been reported infrequently in the medical literature.

Symptoms: Dizziness and Deafness

Symptoms: Dizziness and Deafness

The Prevalence of Hearing Aid Use in Children With Single-Sided Sensorineural Deafness in Oxfordshire

The Prevalence of Hearing Aid Use in Children With Single-Sided Sensorineural Deafness in Oxfordshire

Unusual manifestation of cerebellopontine angle medulloblastoma with tinnitus and sensorineural hearing loss

Abstract BACKGROUND. Medulloblastoma is the most common central nervous system embryonal tumor in children. In adults, this tumor is extremely rare, accounting for nearly 1% of primary brain tumors. Raised intracranial pressure signs are common manifestations of posterior fossa tumors, but tinnitus and/or sensorineural hearing loss are very uncommon presenting symptoms. MATERIAL AND METHODS. Starting from a very rare case of a 39-year-old male with left tinnitus and progressive left sensorineural hearing loss as isolated symptoms of a medulloblastoma, we performed a literature survey using the PubMed, ProQuest, Web of Science, Science Direct, Wiley Online search engines for patients with medulloblastoma and tinnitus and/or sensorineural hearing loss. RESULTS. All patients found in the relevant literature with auditory dysfunctions presented sensorineural hearing loss. Other frequent manifestations were: ataxia, facial numbness, vertigo, headache, nystagmus. Two patients were found with tinnitus and sensorineural hearing loss as isolated symptoms of medulloblastoma, as in our case, and in two other cases the sensorineural hearing loss was the unique symptom. With refers to the onset of medulloblastoma, just 3 patients had the first symptoms sensorineural hearing loss and tinnitus. Concerning the tumor location, in patients manifested with isolated tinnitus and sensorineural hearing loss, like our patient, the tumor arised from the internal auditory meatus, extended to the cerebellopontine angle or involved the vestibulocochlear nerve. With regards to treatment, surgery in association with radiotherapy and chemotherapy was elected in most cases (38%). CONCLUSION. It is important to pay attention at patients with isolated auditory dysfunction that may mimic significant posterior fossa tumors, such as a medulloblastoma.

Transient profound hearing loss and severe facial nerve palsy in schwannomas within the internal acoustic canal: A case report.

Vestibular schwannoma is the most common intracranial schwannoma and constitutes ~8% of all intracranial tumors in adults with an estimated incidence rate of ~1.3/100.000. Facial nerve schwannomas and cochlear nerve schwannomas are rare, and information regarding incidence rates of these is still missing in the literature. All three variants of nerve origin present most frequently with unilateral hearing loss, unilateral tinnitus and disequilibrium. Facial nerve palsy is a common finding in facial nerve schwannomas but a rare finding with vestibular schwannomas. The symptoms are normally persistent and often progress over time, leading to therapeutic interventions that predispose to quality of life-reducing morbidities, e.g., deafness and/or imbalance. The case report describes a 17-year-old male who, during a 1-month period, presented with profound unilateral hearing loss and severe facial nerve palsy followed by complete remission. An MRI scan showed a 5×8-mm schwannoma within the internal acoustic canal. Profound hearing loss together with concomitant severe peripheral facial nerve palsy in small schwannomas within the internal acoustic canal may show spontaneous and total remission within weeks of symptom debut. This knowledge, as well as possible remission of objective findings, should be considered before interventions with potential severe morbidity are suggested.

Comparing Linear and Volumetric Tumor Measurements During Observation of Growing Sporadic Vestibular Schwannomas.

To assess the correlation between linear and volumetric changes in vestibular schwannomas (VS). Retrospective imaging review was performed on patients diagnosed with sporadic VS from 2000 to 2019 who demonstrated linear growth on observation with serial magnetic resonance imaging (MRI). Two large tertiary care centers. Changes in diameter on serial MRI scans, measured by 1995 American Academy of Otolaryngology-Head and Neck Surgeryguidelines, were compared to changes in volume, calculated by segmentation. Ninety-two patients had VS confined to the internal auditory canal (IAC) with 236 MRIs analyzed, and 108 patients had VS involving the cerebellopontine angle (CPA) with 193 MRIs analyzed. The Spearman rank correlation coefficients between changes in diameter and volume for IAC and CPA tumors were 0.43 (p < .001) and 0.65 (p < .001), respectively. Linear diameter increases of 1 to <2 mm corresponded to a median volume change of 32% (interquartile range [IQR]: 6%-86%) for IAC tumors, compared to 23% (IQR: 13%-40%) for CPA tumors. Linear diameter increases of 2 to <3 mm (ie, the minimum linear diameter change classically considered "true growth") corresponded to a median volume change of 42% (IQR: 23%-100%) and 47% (IQR: 26%-69%) for IAC and CPA tumors, respectively. Changes in linear diameter significantly correlated with changes in volume for IAC and CPA tumors, although diameter changes that did not meet the definition of linear growth (<2 mm) had corresponding median volume changes in excess of 20% for both IAC and CPA tumors.

Preservation of the integrity of facial nerve in vestibular schwannoma microsurgery: A consecutive study of 127 clinical cases focusing on nervus intermedius.

Nervus intermedius (NI) injuries are not given enough attention by neurosurgeons during vestibular schwannoma (VS) surgery. Preservation of NI function is essential for the integrity and continuity of the facial nerve, although this can be challenging. We identified the risk factors for NI injury and proposed our experience for optimizing NI preservation based on our cases. We retrospectively analyzed clinical data from a consecutive series of 127 patients with VS who underwent microsurgery via the retrosigmoid approach from 2017 to 2021 at our institution. The baseline characteristics of the patients were collected from the medical records, and the incidence of NI dysfunction symptoms was obtained by outpatient and online video follow-up 6 months after surgery. The surgical procedures and techniques used were described in detail. The data were analyzed in relation to sex, age, tumor location (left or right), Koos grading scale, internal acoustic canal (IAC) invasion (TFIAC Classification), brainstem adhesion, tumor characteristics (cystic or solid), tumor necrosis, and preoperative House-Brackmann (HB) grading by univariate and multivariate analyses. Gross tumor removal was achieved in 126 (99.21%) patients. Subtotal removal was performed on one patient (0.79%). Twenty-three of our cases exhibited facial nerve palsy preoperatively; 21 patients had HB grade II facial palsy, and two had HB grade III. Two months after surgery, 97 (76.38%) patients had normal function of the motor portion of the facial nerve; 25 (19.69%) patients had HB Grade II facial palsy, five had Grade III (3.94%), and zero (0%) had Grade IV. Postoperatively, 15 patients experienced newly gained dry eyes (11.81%), whereas 21 cases of lacrimal disturbances (16.54%), nine of taste disturbances (7.09%), seven of xerostomia (5.51%), five of nasal hypersecretions (3.94%), and seven of hypersalivation (5.51%) were identified in our cases. Univariate and multivariate analyses revealed that the Koos grading scale and tumor characteristics (solid or cystic) were correlated with NI injury (p <0.01). The data in this study demonstrate that although the motor function of the facial nerve is well preserved, NI disturbance is still common after VS surgery. Maintaining the integrity and continuity of the facial nerve is key to NI function. Performing bidirectional and subperineurium dissection based on even and adequate debulking is beneficial for NI preservation in VS surgery. Higher Koos grading and cystic characteristics of VS are associated with postoperative NI injuries. These two parameters can be used to guide the delineation of surgical strategy and predict the prognosis of NI function preservation.

Nervus intermedius: Microsurgical and anatomic relationships to the cerebellopontine angle neurovascular complex.

The nervus intermedius (NI) comprises fibers originating from the trigeminal, superior salivary, and solitary tract nuclei, which join the facial nerve (cranial nerve [CN] VII). Neighboring structures include the vestibulocochlear nerve (CN VIII), the anterior inferior cerebellar artery (AICA), and its branches. Microsurgical procedures at the cerebellopontine angle (CPA) benefit from understanding NI anatomy and relationships, especially for the microsurgical treatment of geniculate neuralgia, where the NI is transected. This study sought to characterize common relationships between the NI rootlets, CN VII, CN VIII, and the meatal loop of AICA at the internal auditory canal (IAC). Seventeen cadaveric heads underwent retrosigmoid craniectomy. Following complete unroofing of the IAC, the NI rootlets were individually exposed to identify their origins and insertion points. The AICA and its meatal loop were traced to assess their relationship with the NI rootlets. Thirty-three NIs were identified. The median number of NI rootlets was 4 per NI (interquartile range, 3-5). The rootlets mainly originated from the proximal premeatal segment of CN VIII (81 of 141, 57%) and inserted onto CN VII at the IAC fundus (89 of 141, 63%). When crossing the acoustic-facial bundle, the AICA most frequently passed between the NI and CN VIII (14 of 33, 42%). Five composite patterns of neurovascular relationships were identified regarding NI. Although certain anatomical trends can be identified, the NI has a variable relationship with the adjacent neurovascular complex at the IAC. Therefore, anatomical relationships should not be used as the sole method of NI identification during CPA surgery.

Radiological presence of vascular loops in the cerebellopontine angle region in patients with unilateral Ménière’s disease

ObjectiveThe relationship between vascular compression of the vestibulocochlear nerve and audio-vestibular symptoms remains controversial. We aimed to examine the radiological features of vascular loops signs in cerebellopontine angle (CPA) and internal auditory canal (IAC) in patients with unilateral Ménière’s disease (MD).MethodsOne hundred and thirty-seven patients with unilateral definite MD and 69 control subjects (138 ears) were enrolled. All subjects received magnetic resonance imaging of CPA-IAC. The configuration of vascular loops in CPA-IAC, based on the Kazawa classification system, from MD-affected, non-affected and control ears were compared. The associations between imaging findings and Ménière’s stage, electrocochleogram (EcochG) and caloric test were analyzed.Results(1) Among the MD-affected ears, 6 cases (4.4%) were classified as Kazawa type IA, 27 cases (19.7%) as IB, 60 cases (43.8%) as IIA, and 44 cases (32.1%) as IIB. No significant interaural difference in the distribution of Kazawa's types was found ({x}^{2} = 4.737, p = 0.578) in unilateral MD patients. (2) The distribution of Kazawa's types were not significantly different between the MD-affected ears and the control subjects ({x}^{2} = 2.876, p = 0.411). (3) No relationship was found between Kazawa staging of the MD-affected ear and Ménière’s stage (H = 2.679, p = 0.444), EcochG ({x}^{2} = 0.827, p = 0.867) and caloric test ({x}^{2} = 4.116, p = 0.248).ConclusionsIn patients with unilateral MD, the configuration of vascular loops in CPA-IAC region, measured by Kazawa criteria, did not correlate with the laterality, clinical stage, the results of EcochG and caloric test, suggesting that vascular loops may be natural anatomical variations for patients with MD.

Effect of Head Position and Magnetic Resonance Sequence on Cochlear Implant-Related Artifact Size and Internal Auditory Canal Visibility.

To assess whether cochlear implant (CI)-related magnetic resonance imaging (MRI) artifact and visibility of the internal auditory canal (IAC) can be improved with head positioning and select MRI sequences. CI-related MRI artifact limits the use of CIs in otherwise good candidates because of the need for serial MRIs for monitoring of pathology. This most notably impacts patients with tumors of the cerebellopontine angle and IAC. Two cadaver heads were implanted with either a Med-El CONCERT (fixed magnet) or SYNCHRONY (rotating magnet) device. Each head was imaged in a 1.5T scanner in 11 different positions. The SYNCHRONY-implanted head was also imaged in a 3.0T scanner in seven positions. Artifact size and IAC visibility (graded on a Likert scale) were measured for each head position by a neuroradiologist. The CONCERT CI produced significantly smaller artifact than the SYNCHRONY CI (effect size, 14.65 mm; p < 0.001). There was no significant difference between CI models in regard to IAC visibility. No head positions were statistically significantly better than neutral position for minimizing artifact size or IAC visibility, although some positions resulted in significantly larger artifact (effect sizes, 2.1-14.3 mm; p < 0.05) or significantly poorer IAC visibility (effect size, 1.4; p < 0.01). The T2 three-dimensional (CISS/FIESTA) sequence demonstrated significantly smaller artifact than T1 sequences, whereas T1 sequences demonstrated significantly better IAC visibility than T2 sequences. Head positioning and magnetic resonance sequence selection impact CI-related artifact size and IAC visibility.

Cochlear nerve dysplasia in unilateral severe to profound congenital sensorineural hearing loss – Prevalence in Australian children and the impact of socioeconomic disadvantage on its management

Congenital unilateral sensorineural hearing loss (cuSNHL) carries potentially significant social, educational, and developmental consequences. Early diagnosis enables investigation, and consideration of options for management and early intervention, helping to mitigate the effects of hearing loss. Cochlear nerve dysplasia (CND) is a prominent cause of cuSNHL and may affect candidacy for cochlear implantation. Socioeconomic disadvantage may impact on a patient's family's capacity to participate in necessary intervention and follow-up. Infants with severe-profound cuSNHL referred to a large Australian quaternary pediatric center between October 2004 and December 2020 were retrospectively included. Audiometric and clinical data, and the presence of hearing loss risk factors were obtained from a prospectively collated database. In Australia MRI scans are provided free-of-charge to citizens and residents. MRI scans were reviewed to determine the status of the nerves within the internal acoustic meatus (IAM grade) along with attendance rates. Travel distance to the hospital was also calculated. Reasons for non-attendance at MRI were obtained from patient medical records and correspondence. Socioeconomic, educational, and occupational indices, and travel distances were obtained using patient residential postcodes with reference to Australian Bureau of Statistics data. A total of 98 patients were reviewed, 64.3% (n=63) of whom underwent MRI. The median age at diagnosis was 40 days (IQR 27). The prevalence of CND was 75% (n=47). Importantly, there was no significant difference in the degree of hearing loss between IAM grades (F(4,57)=1.029, p=0.405). Socioeconomic indices were significantly lower in patients not attending MRI investigations compared with patients who did attend. Travel distance was not significantly different between the two groups. CND is a prominent cause of cuSNHL in Australian infants. MRI at a young age allows parent education regarding management options and timely intervention where indicated. Socioeconomic disadvantage significantly impacts on participation in further routine assessment of cuSNHL, potentially limiting management options for these children long term.

Analysis of molecular genetics and clinical characteristics of 3 children with Waardenburg syndrome

Objective:To analyze the molecular genetics and clinical characteristics of 3 children with syndromic deafness were analyzed to clarify their causative genes and genetic characteristics. Methods:The medical records of 3 children and their parents were collected and analyzed, including physical examination, hearing evaluation, temporal bone CT, and cranial MRI. Whole-exome sequencing（WES） was used to screen for pathogenic gene variants, and Sanger sequencing was used to verify the candidate positive variants in the probands and their parents. Results:All 3 patients were female with normal intelligence. Patient 1 and 3 had a family history of deafness, which conformed to the pattern of autosomal dominant inheritance. All three patients had bilateral profound sensorineural hearing impairment with bright-blue sclera. Other phenotypes included hypertelorism（patient 1）, multiple dyschromatosis（patient 2）, and yellowish hair（patient 2）, blepharoptosis（patient 3）. Patient 3 had bilateral vestibular enlargement, internal auditory canal enlargement, and bilateral inner ear malformations. Mother of patient 1 had only left mild hearing impairment; mother of patient 3 had bilateral hearing impairment with unilateral bright-blue sclera and yellowish hair. WES detected heterozygous variants, PAX3 c.811C>T, MITF c.632T>C, and SOX10 c.1359_1360 insGCCCCACA, in patient 1, 2, and 3, respectively. The variants in patient 1 and 3 were inherited from their mothers who had hearing impairment, and MITFvariant in patient 2 may be a spontaneous variation. The final diagnoses were that patient 1 with Waardenburg syndrome type 1（WS1）, and the mother of patient 1, patient 2, patient 3, and the mother of patient 3 with WS2. Conclusion:WS is a syndromic deafness, and the main clinical features include autosomal dominant inheritance and scleral pigment abnormalities. However, the findings of this study show that there is still phenotypic heterogeneity in WS even caused by the same gene variant, so it depends on genetic tests to confirm the diagnosis; The gene variant of patient 1 and 2 was never been reported in other patients, which expands the pathogenic variant spectrum of WS.

A Rare Case of Pleomorphic Adenoma in the Internal Auditory Canal.

Pleomorphic adenoma is a common tumor of the salivary gland tumor, but it is rare in the ear. To the authors' knowledge, this patient is the first reported case of pleomorphic adenoma arising in the internal auditory canal. There have been few documents reporting the manifestations and the therapy strategy of this disease. This study clearly demonstrated the experience in treating pleomorphic adenoma, including the characteristics of the clinical manifestation, the key procedures of surgery, and key points of the diagnosis. The translabyrinthine approach under the microscope performed to remove this tumor is a good option for resecting this type of tumor.

Imaging Study &amp; Surgical Perspective Of Cochlear Implantees

Introduction: A cross-sectional prospective clinical study was done to evaluate the inner ear anomalies in candidates undergoing cochlear implantation. Materials and Methods: Study was carried out over a period of 07 years (Jan 2013 to Dec 2019) at Cochlear Implant Centre, Combined Military Hospital Dhaka. A total 206 deaf candidates, both pre and post lingual, were included in convenient sampling method. Result: The sample consisted of 206 candidates, of whom 117 (56.80%) were female and 89 (43.20%) were male. All candidates had severe to profound bilateral deafness. 182 (88.35%) of them were pre and 24 (11.65%) were in post lingual group. All patients diagnosed audiologically as profound deafness underwent HRCT scan of temporal bone with 3D reconstruction of cochlea and MRI of internal auditory canal &amp; brain. Radiological examination revealed that 36 (17.47%) candidates had ear anomalies. Mondini deformity 14 (06.80%), cochlear ossification 11 (5.34%), large vestibular aqueduct 04 (1.94%), high jugular bulb 04 (1.94%) and anteriorly placed sigmoid sinus 03 (1.45%) were noted. During intervention, 42 (20.39%) candidates had anomalous intra operative findings. Among them CSF gusher 19 (9.23%), ossification of basal turn 12 (5.83%), isolated rotated Cochlea 02 (0.97%), high jugular bulb 04 (1.94%), anteriorly placed sigmoid sinus 03 (1.45%), and very high facial nerve 02 (0.97%) were observed. During surgery, electrode insertion difficulty due to high CSF gusher was experienced in19 (9.23%) cases, full length of electrode insertion was not possible due to ossified basal turn 12 (5.83%), difficult to find out round window membrane due to rotated cochlea 02 (0.97%), prevented direct visualization of the round window due to high jugular bulb 04 (1.94%), difficult to approach round window due to very high facial nerve 02 (0.97%). and approach to round window membrane was compromised due to anteriorly placed sigmoid sinus 03 (1.45%). Most of these difficulties were effectively managed during surgery. Conclusions: This study highlights the importance of preoperative radiological scanning in the assessment of patients undergoing cochlear implantation. It provides vital information on cochlear status and in ruling out non cochlear causes where cochlear implantation is not feasible. Detection of anatomical abnormalities with appropriate evaluation, specially imaging should be mandatory in every patient undergoing cochlear implantation. J Dhaka Med Coll. 2021; 30(2) : 167-175

Internal Auditory Canal (IAC) and Cerebellopontine Angle (CPA): Comparison between T2-weighted SPACE and 3D-CISS sequences at 1.5T

MR cisternography relies on three-dimensional (3D) heavily T2-weighted imaging techniques. It can be used to assess the internal auditory canal (IAC) and Cerebellopontine Angle (CPA) anatomy and pathology. There are two techniques usually used for this purpose; T2-weighted SPACE and Three-Dimensional Constructive Interference in Steady State (3D-CISS). The current study aims to evaluate differences in image quality between 3D-CISS and T2-weighted SPACE sequences and to compare their ability to differentiate the anatomy of the CPA and IAC structures. This study was conducted in 64 patients. Each patient was imaged with both 3D-CISS and T2-weighted SPACE sequences, then the images were also reviewed by two radiologists for anatomy evaluation. The results showed that T2-weighted SPACE outperforms 3D-CISS for the assessments of IAC, cranial nerve, cochlear anatomic structures, semicircular canals, and vestibule. The study also showed there is no statically significant difference between the two sequences according to the gender and the age of patients.

COVID-19 and Spectrum of Vestibular Dysfunctions: A Case Report

COVID-19 infection had shown to affect multiple systems. A positive COVID-19 case with multiple vestibular problems, its management and a review of the literature were reported. A 63-year-old lady who was a Category 5 COVID-19 infection patient, complicated by mild frontal stroke, left isolated mononeuropathy causing foot drop, had persistent dizziness lasting hours to days in the first month after being extubated. She underwent vestibular rehabilitation which did not resolve her vertigo. Upon presentation to the vestibular clinic at 3-months post-extubation, she complained of vertigo on changing positions lasting a few seconds with dizziness in between. Her Dizziness Handicap Inventory (DHI) was severe, with severe abnormal Depression Anxiety Stress Scale 21 (DASS 21). Vestibular assessments showed oculomotor abnormalities with positive left posterior Benign Paroxysmal Positional Vertigo (BPPV) on Dixhallpike test. During Epley maneuver, there was canal conversion to the anterior canal which was resolved with a deep head hanging maneuver. The canal repositioning maneuver was done in serial, and her vertigo reduced tremendously. Her Video Head Impulse Test showed abnormalities in all semicircular canals bilaterally, rotatory chair showed lateral vestibular weakness and videonystagmography showed abnormal smooth pursuit, saccade and optokinetic suggesting central lesion. Her cervical and ocular vestibular evoked myogenic potential were normal reflecting normal saccular and utricular function. Tympanometry showed type A bilaterally with right mild and left mild to moderate sensorineural hearing loss. Magnetic resonance imaging of the Internal Acoustic Meatus showed bilateral vascular loop with no cerebellopontine angle tumour. Upon review three months later, the patient was asymptomatic of vestibular complaint with normal DHI and DASS21 score. Her foot drop had also resolved. Evidence in the literature showed up to 16.8% of COVID-19 patients reported vestibular symptoms. The mechanism of this vestibular neuritis is unclear but may be similar to the pathogenesis causing anosmia or vasculopathy. International Journal of Human and Health Sciences Supplementary Issue: 2023 Page: S26

Enhancement in the Round Window Niche: A Potential Pitfall in High-Resolution MR Imaging of the Internal Auditory Canal.

There is limited discussion in current literature about the normal imaging appearance of the round window. The purpose of this study was to assess the prevalence and imaging characteristics of gadolinium enhancement in the round window niche on MR imaging to the internal auditory canal. The presence or absence and laterality of enhancement in the round window niche on MR imaging was retrospectively reviewed in 95 patients from 1 institution. All studies included high-resolution (≤0.5-mm section thickness) pre- and postgadolinium 3D FSE T1 with fat-saturation and postgadolinium 3D FLAIR image sequences. T1 and T2 acquisitions were viewed as coregistered overlays to confirm that enhancement was lateral to the round window membrane within the round window niche. CT was reviewed when available to assess the presence and laterality of soft tissue in the round window niche. Ninety-five patients with internal auditory canal MRIs were included. Enhancement was present in the round window of 15 of 95 patients (15.8%). Of the 27 patients who underwent CT, 4 (14.8%) had concordant soft tissue on CT and MR imaging enhancement in the round window niche. One patient had MR imaging enhancement within the round window niche without a corresponding abnormality on CT. The absence of soft tissue on CT and the corresponding lack of MR imaging enhancement were present in 22 (81.5%) patients. Enhancement can be visualized within the round window niche on MR imaging as an incidental finding. This enhancement probably represents postinflammatory granulation tissue and does not require further intervention. However, the potential for this enhancement to be misdiagnosed as a pathologic process can be a pitfall in MR imaging.