Cause Of Sensorineural Hearing Loss Research Articles

Routine Vestibular Function Assessment in Children With Congenital CMV: Are We Ready?

Routine Vestibular Function Assessment in Children With Congenital CMV: Are We Ready?

Congenital Cytomegalovirus Infection in Pregnancy: A Case Report with Sequential Fetal Brain Changes and the Latest Information on Diagnosis, Treatment and Prevention

Congenital cytomegalovirus (CMV) infection is the most common nongenetic cause of sensorineural hearing loss and a major cause of visual, intellectual, and neurodevelopmental impairment worldwide. The seroprevalence of CMV among women of childbearing age in developing countries reaches almost 100%, and the incidence of CMV infection in neonates is 1%–2%. Approximately 87% of the infected neonates are asymptomatic at birth and 13% of them have permanent sequelae. The burden of congenital malformations due to congenital CMV infection is higher than that due to Down syndrome, fetal alcohol syndrome, and spina bifida. Nevertheless, there is little knowledge regarding congenital CMV pathogenesis, diagnosis, treatment, and prevention. In this study, we report a case that showed sequential changes of fetal brain following CMV infection in pregnancy. Additionally, we reviewed the latest information on the diagnosis, treatment, and prevention of congenital CMV infection.

CSF Otorhinorrhea Due to Inner Ear Malformation-A Case Report.

Inner ear malformations are an important cause of sensorineural hearing loss ranging from severe to profound and they also contribute to Cerebrospinal fluid leakage and recurrent meningitis. The most severe is the complete labyrinthine aplasia (Michel Deformity), then there is cochlear aplasia, cochlear hypoplasia, incomplete partition of the cochlea, enlarged vestibular acqueduct and cochlear aperture abnormality.

Hearing Loss Caused by HCMV Infection through Regulating the Wnt and Notch Signaling Pathways.

Hearing loss is one of the most prevalent sensory disabilities worldwide with huge social and economic burdens. The leading cause of sensorineural hearing loss (SNHL) in children is congenital cytomegalovirus (CMV) infection. Though the implementation of universal screening and early intervention such as antiviral or anti-inflammatory ameliorate the severity of CMV-associated diseases, direct and targeted therapeutics is still seriously lacking. The major hurdle for it is that the mechanism of CMV induced SNHL has not yet been well understood. In this review, we focus on the impact of CMV infection on the key players in inner ear development including the Wnt and Notch signaling pathways. Investigations on these interactions may gain new insights into viral pathogenesis and reveal novel targets for therapy.

Outcome of Cochlear Implantation in Postmeningitis Profound Sensorineural Hearing Loss at Rajavithi Hospital

Background: Bacterial meningitis is one of the major factors in the etiology of acquired sensorineural hearing loss in children and adults. Cochlear implantation in these patients is challenging because of inner ear ossification and fibrosis, and this procedure sometimes achieves poorer outcomes in this scenario than with other causes of sensorineural hearing loss. There has been little research into the factors affecting the outcomes of this procedure. Objective: To evaluate the outcomes of cochlear implantation in patients with postmeningitis profound sensorineural hearing loss and to evaluate the factors that affect the results. Materials and Methods: A retrospective review was conducted of thirty patients who were diagnosed with post meningitis profound hearing loss and underwent cochlear implantation at Rajavithi Hospital between 2001 and 2016. Preoperative language status, duration of deafness, preoperative imaging, and degree of electrode insertion were recorded. Categories of auditory performance-II test (CAP-II) was evaluated in all cases, one year postoperative. Results: Thirty postmeningitis deafness patients underwent cochlear implantation. The median age at diagnosis of meningitis and age at implantation were 41 years (range 1 to 75) and 49.50 years (range 3 to 75), respectively. The median duration of deafness was 12 months (range 4 to 300), and the overall mean CAP-II at one year after surgery was 5.47±2.21. The postlinguistic group had a significantly higher CAP-II score than the prelinguistic one (p=0.006). Electrodes were successfully totally inserted in 19 patients (63.3%) and partially inserted in 11 (36.7%). The average CAP-II score in the group with fully-inserted electrodes was significantly higher than in the group with partially-inserted electrodes (p=0.045). There was no correlation between CAP-II score and age at meningitis diagnosis (p=0.069), age at time of surgery (p=0.105), duration of deafness (p=0.506), or preoperative CT (p=0.228) or MRI abnormality (p=0.078). Conclusion: Cochlear implantation in patients with postmeningitis profound hearing loss had high success rates and favorable outcomes. Preoperative language status and degree of electrode insertion were factors that affected auditory performance results. Keywords: Cochlear implantation, Postmeningitis hearing loss, Sensorineural hearing loss, Meningitis, Rajavithi Hospital

Vestibular, Gaze, and Balance Disorders in Asymptomatic Congenital Cytomegalovirus Infection.

Congenital cytomegalovirus (cCMV) is the leading nongenetic cause of sensorineural hearing loss and developmental disabilities. Because there are limited data from studies of vestibular involvement in select groups of children with cCMV, the true frequency of vestibular disorders in cCMV is likely underestimated. Our objective for this study is to determine the prevalence of vestibular, gaze, and balance disorders in a cohort of children with asymptomatic cCMV. Comprehensive vestibular, gaze, and balance assessments were performed in 40 children with asymptomatic cCMV. The function of semicircular canals of the inner ear and vestibulo-visual tract were assessed by measuring vestibulo-ocular reflex in a computer-driven motorized rotary chair; inner ear saccular function was assessed by using cervical vestibular evoked myogenic potential; gaze stability during head movement was assessed by using clinical dynamic visual acuity, and balance was assessed by using the sensory organization test and the Bruininks-Oseretsky Test of Motor Proficiency, Second Edition. Test results for each variable were compared with those of a control group without cCMV and/or compared to age-matched normative published data. Vestibular disorders were evident in 45% of the cohort on the basis of rotary chair and cervical vestibular evoked myogenic potential testing, suggesting abnormalities in semicircular canals, the utricle and saccule of the inner ear, and vestibulo-visual tracts. Additionally, 46% of the cohort had difficulties maintaining gaze during head movement, and one-third to one-half of the cohort had difficulties maintaining balance. Vestibular, gaze, and balance disorders are highly prevalent in children with asymptomatic cCMV. Systematic screening for vestibular disorders will be used to determine the full clinical impact for the development of effective interventions.

Nonsyndromic Congenital Causes of Sensorineural Hearing Loss in Children: An Illustrative Review.

OBJECTIVE. The purpose of this article is to provide an illustrative review of nonsyndromic congenital causes of sensorineural hearing loss (SNHL) in children. CONCLUSION. Early recognition and treatment are essential in maximizing developmental outcomes in children with congenital SNHL. Because imaging plays an integral role in identifying underlying causes of SNHL, it is imperative that radiologists be able to recognize, describe, and appropriately categorize the spectrum of congenital inner ear malformations in children.

Familial Phenotype of Waardenburg Syndrome in One Family: A Case Series

Waardenburg syndromeis an accumulation of some genetic conditions which leads to sensorineural hearingloss (SNHL) and depigmentation of hair, skin, and eyes. The cause of sensorineural hearing loss in childrencan be congenital or hereditary, characterized by sensorineural deafness, associated with pigment disordersand tissue defects. Based on the accompanying symptoms, Waardenburg syndrome is divided into 4 types,where the most often ones are type 1 and 2. Clinical symptoms including dystopia canthorum, pigmentdisorders (white crest, abnormalities of eyebrow, eyelashes, body hair and iris heterochromia), sensorineuraldeafness, protruding nose and depigmentedhair at young age. Based on physical and additional examinationsperformed on five patients, all results showed mayor and minor symptoms of waardenberg syndromeaccompanied by dystopia canthorum, therefore classified aswaardenburg type 1.Conclusion: All patients are classified as type 1 Waandenberg syndrome which were inherited in the formof autosomal dominant.

Assessment of cochlear function in children with sickle cell anemia

Background: Sickle cell disease is characterized by vaso-occlusion which leads to impaired blood supply to several organs. The cochlear in particular has been known to be highly sensitive to anoxia which is, in turn, a proven cause of sensorineural hearing loss (SNHL). Early detection of hearing loss is paramount in these patients, as the cochlear ischemic damage is repetitive and progressive. Once the damage is sufficiently enough to cause noticeable hearing loss, the loss is mostly substantial and irreversible. Otoacoustic emission is useful in detecting early cochlear damage. Materials and Methods: Children with sickle cell anemia (SCA) (HbSS) aged between 1 and 12 years diagnosed by hemoglobin electrophoresis and equal number of controls matched (HbAA) matched for age and sex were recruited for the study. All participants underwent a detailed ear, nose, and throat examination and tympanometry. Those with normal middle ear function were further subjected to transient-evoked otoacoustic emissions (TEOAEs) testing. Results: There were 60 patients with SCA (cases) and 60 controls. The age of the participants ranged between 1–12 years with a mean of 6.5 ± 3.74 among the cases and 7.02 ± 3.54 among the controls. The male–female ratio was 0.9:1. Among participants with normal middle ear function, TEOAE was abnormal in 43 (48.8%) ears of the cases and 70 (73.7%) ears of the controls. There was a statistically significant difference in abnormal TEOAEs outcome between cases and the control group (P = 0.002). Conclusion: Children with SCA had a high rate of abnormal cochlear function. Therefore, there is a need for periodic monitoring of cochlear function in these patients so as to detect and treat SNHL early.

1143. Late-Onset Hearing Loss and Antiviral Therapy for Congenital Cytomegalovirus Infection

BackgroundCongenital cytomegalovirus (CMV) is the leading non-genetic cause of sensorineural hearing loss (SNHL) in children. While SNHL is often present at birth, as many as 25% of congenital CMV-infected infants may develop late-onset hearing loss. Antiviral therapy improves hearing outcomes, but its effect on the occurrence of late-onset SNHL is not fully known. Thus, our objective was to describe the prevalence of late-onset SNHL among congenital CMV-infected children treated with antiviral therapy in the first month of age.MethodsFrom 2013 to present, infants with congenital CMV infection referred to Nationwide Children’s Hospital’s (NCH) NEO-ID Clinic, Columbus, OH underwent complete evaluation including hearing testing. Pertinent demographic, clinical, laboratory, and radiographic data were obtained and managed using REDCap electronic data capture tools. Infants who passed the newborn hearing screen and subsequently developed late-onset SNHL were identified and compared with respect to receipt of antiviral therapy in the neonatal period. Statistical analyses were performed using GraphPad Prism for macOS version 8.3.0.ResultsDuring the 6-year study period, 99 infants had congenital CMV infection and 69 (70%) of them passed the newborn hearing screen. 46 (46%) neonates received antiviral therapy (1, ganciclovir; 38, valganciclovir; 7, both) for clinically apparent congenital CMV infection. One (2%) child developed late-onset SNHL.This infant was born at 37 weeks’ gestation (birth weight, 2525 g) with microcephaly (head circumference, 31 cm) and cerebral calcifications and was diagnosed with congenital CMV infection at 8 days of age. Treatment with valganciclovir was initiated at 9 days of age, and he developed mild unilateral SNHL at 1 month of age while on treatment and subsequently right severe-profound SNHL and left mild-moderate SNHL. In comparison, among 23 infants with clinically inapparent disease who passed the newborn hearing screen and did not receive antiviral therapy, 5 (22%) subsequently developed SNHL (p=0.014).ConclusionInfants who received antiviral therapy for clinically apparent congenital CMV infection had significantly less late-onset SNHL than untreated infants, thus supporting a hearing protective effect of antiviral treatment.Disclosures All Authors: No reported disclosures

Diagnostic Assessment of Progressive Fluctuating Sensorineural Hearing Loss in Children

Deterioration of auditory thresholds in young children is directly associated with negative impact on language development. Early detection of the cause of sensorineural hearing loss eases proper intervention and signalizes valuable prognostic data. Nowadays, the etiology of pediatric hearing loss has been modified, attributable to progresses in gene testing and adequate management of birth infections. This paper updates well known risk factors for progression along with fluctuation of hearing acuity involving health hazard indicators, auditory, laboratory and clinical manifestations of such young patients. This review takes into consideration the most well-known risk indicators associated with an increased likelihood of progressive hearing loss (including but not limited to neonatal intensive care unit admission, family history of hearing loss, various syndromes, prenatal and postnatal infections etc.). Prompt post neonatal monitoring of hearing, leading to early hearing loss identification, is crucial to optimize management and therefore appropriate intervention.

Effects of cochlear hair cell ablation on spatial learning/memory

Current clinical interest lies in the relationship between hearing loss and cognitive impairment. Previous work demonstrated that noise exposure, a common cause of sensorineural hearing loss (SNHL), leads to cognitive impairments in mice. However, in noise-induced models, it is difficult to distinguish the effects of noise trauma from subsequent SNHL on central processes. Here, we use cochlear hair cell ablation to isolate the effects of SNHL. Cochlear hair cells were conditionally and selectively ablated in mature, transgenic mice where the human diphtheria toxin (DT) receptor was expressed behind the hair-cell specific Pou4f3 promoter. Due to higher Pou4f3 expression in cochlear hair cells than vestibular hair cells, administration of a low dose of DT caused profound SNHL without vestibular dysfunction and had no effect on wild-type (WT) littermates. Spatial learning/memory was assayed using an automated radial 8-arm maze (RAM), where mice were trained to find food rewards over a 14-day period. The number of working memory errors (WME) and reference memory errors (RME) per training day were recorded. All animals were injected with DT during P30–60 and underwent the RAM assay during P90–120. SNHL animals committed more WME and RME than WT animals, demonstrating that isolated SNHL affected cognitive function. Duration of SNHL (60 versus 90 days post DT injection) had no effect on RAM performance. However, younger age of acquired SNHL (DT on P30 versus P60) was associated with fewer WME. This describes the previously undocumented effect of isolated SNHL on cognitive processes that do not directly rely on auditory sensory input.

Congenital Cytomegalovirus Infection: Update on Diagnosis and Treatment.

Congenital cytomegalovirus (cCMV) infection is the most common congenital viral infection and is the leading non-genetic cause of sensorineural hearing loss (SNLH) and an important cause of neurodevelopmental disabilities. The risk of intrauterine transmission is highest when primary infection occurs during pregnancy, with a higher rate of vertical transmission in mothers with older gestational age at infection, while the risk of adverse fetal effects significantly increases if fetal infection occurs during the first half of pregnancy. Despite its prevalence and morbidity among the neonatal population, there is not yet a standardized diagnostic test and therapeutic approach for cCMV infection. This narrative review aims to explore the latest developments in the diagnosis and treatment of cCMV infection. Literature analysis shows that preventive interventions other than behavioral measures during pregnancy are still lacking, although many clinical trials are currently ongoing to formulate a vaccination for women before pregnancy. Currently, we recommend using a PCR assay in blood, urine, and saliva in neonates with suspected cCMV infection. At present, there is no evidence of the benefit of antiviral therapy in asymptomatic infants. In the case of symptomatic cCMV, we actually recommend treatment with oral valganciclovir for a duration of 12 months. The effectiveness and tolerability of this therapy option have proven effective for hearing and neurodevelopmental long-term outcomes. Valganciclovir is reserved for congenitally-infected neonates with the symptomatic disease at birth, such as microcephaly, intracranial calcifications, abnormal cerebrospinal fluid index, chorioretinitis, or sensorineural hearing loss. Treatment with antiviral drugs is not routinely recommended for neonates with the mildly symptomatic disease at birth, for neonates under 32 weeks of gestational age, or for infants more than 30 days old because of insufficient evidence from studies. However, since these populations represent the vast majority of neonates and infants with cCMV infection and they are at risk of developing late-onset sequelae, a biomarker able to predict long-term sequelae should also be found to justify starting treatment and reducing the burden of CMV-related complications.

Is it time for routine prenatal serological screening for congenital cytomegalovirus?

Congenital CMV infection (cCMV) is the most prevalent congenital infection, main non-genetic cause of sensorineural hearing loss (SNHL) and major cause of neurological disability. Despite the burden of cCMV, no Public Health body recommends universal serology screening in pregnancy. This was explained by gaps in knowledge of epidemiology, diagnosis, prognosis and the absence of any validated treatment. Over 10 years, progress has been made in our understanding of cCMV following primary maternal infection. Risk factors have been identified and quantified, notably it is now well recognized that among maternal primary infections only those occurring in the first trimester may lead to long-term sequelae. Algorithms combining IgG, IgM, and IgG avidity detection with serological assays adapted on high throughput platforms have demonstrated high sensitivity and specificity to diagnose maternal primary infection. The prognostic value of prenatal imaging combining ultrasound and MRI has been validated by many studies. Finally, recent data from a randomized controlled study demonstrated the efficacy of early antiviral therapy to prevent vertical transmission. Whether CMV serology screening in the first trimester of pregnancy meets the WHO's criteria for a screening program will therefore be reviewed.

Blood genome expression profiles in infants with congenital cytomegalovirus infection

Congenital CMV infection (cCMVi) affects 0.5–1% of all live births worldwide, making it the leading cause of sensorineural hearing loss (SNHL) in childhood. The majority of infants with cCMVi have normal hearing at birth, but are at risk of developing late-onset SNHL. Currently, we lack reliable biomarkers to predict the development of SNHL in these infants. Here, we evaluate blood transcriptional profiles in 80 infants with cCMVi (49 symptomatic, 31 asymptomatic), enrolled in the first 3 weeks of life, and followed for 3 years to assess emergence of late-onset SNHL. The biosignatures of symptomatic and asymptomatic cCMVi are indistinguishable, suggesting that immune responses of infants with asymptomatic and symptomatic cCMVi are not different. Random forest analyses of initial samples in infants with cCMVi, irrespective of their clinical classification, identify a 16-gene classifier signature associated with the development of SNHL with 92% accuracy, suggesting its potential value as a biomarker.

Advances in Inner Ear Therapeutics for Hearing Loss in Children.

Hearing loss is a common congenital sensory disorder with various underlying causes. Here, we review and focus on genetic, infectious, and ototoxic causes and recent advances in inner ear therapeutics. While hearing aids and cochlear implantation are the mainstay of treatment for pediatric hearing loss, novel biological therapeutics are being explored. Recent preclinical studies report positive results in viral-mediated gene transfer techniques and surgical approaches to the inner ear for genetic hearing loss. Novel pharmacologic agents, on the other hand, show promising results in reducing aminoglycoside and cisplatin ototoxicity. Clinical trials are underway to evaluate the efficacy of antivirals for cytomegalovirus-related hearing loss, and its pathogenesis and other potential therapeutics are currently under investigation. Individualized therapies for genetic and infectious causes of sensorineural hearing loss in animal models as well as pediatric patients show promising results, with their potential efficacy being active areas of research.

Vestibular Function in Children With a Congenital Cytomegalovirus Infection: 3 Years of Follow-Up.

Congenital cytomegalovirus (cCMV) infection is the most common nongenetic cause of sensorineural hearing loss in children. Due to the close anatomical relationship between the auditory and the vestibular sensory organs, cCMV can also be an important cause of vestibular loss. However, the prevalence and nature of cCMV-induced vestibular impairment is still underexplored. The aim of this study was to investigate the occurrence and characteristics of vestibular loss in a large group of cCMV-infected children, representative of the overall cCMV-population. Ninety-three children (41 boys, 52 girls) with a confirmed diagnosis of cCMV were enrolled in this prospective longitudinal study. They were born at the Ghent University Hospital or referred from another hospital for multidisciplinary follow-up in the context of cCMV. The test protocol consisted of regular vestibular follow-up around the ages of 6 months, 1 year, 2 years, and 3 years with the video Head Impulse Test, the rotatory test, and the cervical Vestibular Evoked Myogenic Potential test. On average, the 93 patients (52 asymptomatic, 41 symptomatic) were followed for 10.2 months (SD: 10.1 mo) and had 2.2 examinations (SD: 1.1). Seventeen (18%) patients had sensorineural hearing loss (7 unilateral, 10 bilateral). Vestibular loss was detected in 13 (14%) patients (7 unilateral, 6 bilateral). There was a significant association between the occurrence of hearing loss and the presence of vestibular loss (p < 0.001), with 59% (10/17) vestibular losses in the group of hearing-impaired children compared to 4% (3/76) in the group of normal-hearing subjects. In the majority of the cases with a vestibular dysfunction (85%, 11/13), both the semicircular canal system and the otolith system were affected. The remaining subjects (15%, 2/13) had an isolated semicircular canal dysfunction. Sixty-one patients already had at least one follow-up examination. Deterioration of the vestibular function was detected in 6 of them (10%, 6/61). cCMV can impair not only the auditory but also the vestibular function. Similar to the hearing loss, vestibular loss in cCMV can be highly variable. It can be unilateral or bilateral, limited or extensive, stable or progressive, and early or delayed in onset. As the vestibular function can deteriorate over time and even normal-hearing subjects can be affected, vestibular evaluation should be part of the standard otolaryngology follow-up in all children with cCMV.

MicroRNAs in Noise-Induced Hearing Loss and their Regulation by Oxidative Stress and Inflammation.

Noise exposure (NE) has been recognized as one of the causes of sensorineural hearing loss (SNHL), which can bring about irreversible damage to sensory hair cells in the cochlea, through the launch of oxidative stress pathways and inflammation. Accordingly, determining the molecular mechanism involved in regulating hair cell apoptosis via NE is essential to prevent hair cell damage. However, the role of microRNAs (miRNAs) in the degeneration of sensory cells of the cochlea during NE has not been so far uncovered. Thus, the main purpose of this study was to demonstrate the regulatory role of miRNAs in the oxidative stress pathway and inflammation induced by NE. In this respect, articles related to noise-induced hearing loss (NIHL), oxidative stress, inflammation, and miRNA from various databases of Directory of Open Access Journals (DOAJ), Google Scholar, PubMed; Library, Information Science & Technology Abstracts (LISTA), and Web of Science were searched and retrieved. The findings revealed that several studies had suggested that up-regulation of miR-1229-5p, miR-451a, 185-5p, 186 and down-regulation of miRNA-96/182/183 and miR-30b were involved in oxidative stress and inflammation which could be used as biomarkers for NIHL. There was also a close relationship between NIHL and miRNAs, but further research is required to prove a causal association between miRNA alterations and NE, and also to determine miRNAs as biomarkers indicating responses to NE.

Prevention of Acquisition of Cytomegalovirus Infection in Pregnancy Through Hygiene-based Behavioral Interventions: A Systematic Review and Gap Analysis.

Congenital cytomegalovirus infection is the most common nongenetic cause of sensorineural hearing loss in childhood and an important cause of neurodisability. There is no licensed cytomegalovirus (CMV) vaccine and no antenatal treatment for congenital CMV that is routinely recommended in clinical practice in the United Kingdom. To review the published literature for studies that evaluated preventative hygiene-based interventions in pregnancy for their impact on knowledge about CMV prevention, the uptake of preventative behaviors or the acquisition of CMV in pregnancy. Searches were carried out in Medical Literature Analysis and Retrieval System Online and Cumulative Index of Nursing and Allied Health Literature databases. All human studies, limited to women of childbearing age were included. Two reviewers independently assessed the quality of the methods and results of included articles. Extracted data were classified using Cochrane guidelines. Seven studies met the inclusion criteria. These show that preventative measures are acceptable to pregnant women, can impact their behavior and have the potential to reduce CMV in pregnancy. They are limited by several factors; sample size, nonrandomized trial design and interventions that are beyond routine clinical practice. An effective intervention that changes behavior in pregnancy and reduces the risk of CMV acquisition is needed as part of routine care. There is currently insufficient evidence about the form that this intervention should take. PROSPERO registration number: CRD42017069666.

Diagnostic Yield of MRI for Sensorineural Hearing Loss - An Audit.

Contrast-enhanced magnetic resonance imaging (CEMRI) of the head is frequently employed in investigations of sensorineural hearing loss (SNHL). The yield of these studies is perceptibly low and seemingly at odds with the aims of wise resource allocation and risk reduction within the Canadian healthcare system. The purpose of our study was to audit the use and diagnostic yield of CEMRI for the clinical indication of SNHL in our institution and to identify characteristics that may be leveraged to improve yield and optimize resource utilization. The charts of 500 consecutive patients who underwent CEMRI of internal auditory canal for SNHL were categorized as cases with relevant positive findings on CEMRI and those without relevant findings. Demographics, presenting symptoms, interventions and responses, ordering physicians, and investigations performed prior to CEMRI testing were recorded. Chi-squared test and t-test were used to compare proportions and means, respectively. CEMRI studies revealed relevant findings in 20 (6.2%) of 324 subjects meeting the inclusion criteria. Pre-CEMRI testing beyond audiometry was conducted in 35% of those with relevant positive findings compared to 7.3% of those without (p < 0.001). Auditory brainstem response/vestibular-evoked myogenic potentials were abnormal in 35% of those with relevant CEMRI findings compared to 6.3% of those without (p < 0.001). CEMRI is a valuable tool for assessing potential causes of SNHL, but small diagnostic yield at present needs justification for contrast injection for this indication. Our findings suggest preferred referral from otolaryngologists exclusively, and implementation of a non-contrast MRI for SNHL may be a better diagnostic tool.