Inner Ear Research Articles

Otitis externa: a review

Otitis, or inflammation of the pinna, ear canal and possible middle or internal ear structures, is a very common clinical presentation in dogs. Often patients with otitis suffer from recurrent disease. This can be very frustrating for the pet, owner and attending vet alike. It is important to adopt a logical approach to these cases to avoid a vicious cycle of otitis, treatment, temporary improvement and relapse. Numerous factors are part of the disease and it is crucial to identify and correct as many of these factors as possible.

Differences in vestibulo-ocular reflex time constants in patients with vestibular migraine versus vestibular neuritis/labyrinthitis

ObjectiveRecurrent dizziness, vertigo, and imbalance, as well as nausea or vomiting, can be induced by central or peripheral vestibular pathology. Vestibular migraine (VM) is a central pathology in which migraines reciprocally interact with vestibular nuclei. Vestibular neuritis and labyrinthitis (VN/L) are peripheral diseases involving inflammation of structures in the vestibular nerve or labyrinth. Because VM and VN/L in early stages can produce similar symptoms, diagnosis may require prolonged clinical evaluation. It has been suggested that differences in a patient's Vestibulo-Ocular Reflex (VOR) measured during the rotary chair step rotation test (RCS Test) can differentiate VM from peripheral pathologies, allowing for faster diagnosis. We sought to compare VOR time constants (VORTcs) in patients with VM versus VN/L, with the goal of exploring potential diagnostic value. Study designRetrospective chart review of patients seen at a hospital balance center between January 2010 and June 2019. SettingTertiary referral center. Patients68 patients (mean age = 58.15, 65 % female, 35 % male) were placed into two groups based on clinical diagnosis codes: 1) VM or 2) VN/L. Main outcome measure(s)Primary variable of VORTc, evoked by rotational step testing. ResultsPatients in the VM group demonstrated statistically significant elevated VOR Tcs outside the normed range of 10–19.5 compared to those in the VN/L group (p = 0.0003) while patients in the VN/L group demonstrated statistically significant shortened VOR Tcs (p = 0.0443) with the two populations having distinctly different VOR Tc profiles. ConclusionsOur results support the conclusion that elevated VOR Tcs are a sign of central vestibular pathology and highlight the benefit of utilizing rotary chair testing early in the diagnostic process as a powerful diagnostic tool when evaluating dizzy patients for central versus peripheral vestibular dysfunction. Our results suggest more particularly that elevated VOR Tcs can be utilized to identify patients with vestibular migraine, thus offering differentiation from patients with peripheral vestibular dysfunction earlier in the process of diagnosis, with an opportunity for earlier intervention.

Surfing-Related Craniofacial Injuries: A NEISS Database Study.

Surfing is a popular pastime in coastal areas around the world with increasing numbers of participants. There is a lack of detailed data in the literature regarding surfing-related head and neck (HN) injuries. We queried the National Electronic Injury Surveillance System (NEISS) database to characterize patient demographics, injury types, injury subsite, and emergency department (ED) disposition status associated with surfing-related HN injuries between 2009 and 2020 in the United States. A total of 54,978 estimated national cases were reported from 2009 to 2020. Injuries to the head (36.0%) and neck (35.8%) were most common. Young adults (ages 18-35) made up most ED visits, whereas older adults (>35) made up most (63.5%) admissions. Laceration (46.1%) was the most common injury among ED visits, whereas fracture (30.5%) and internal injury (29.2%) were most common in admitted patients. Concussions represented 7.5% of injuries overall, 9.1% of pediatric injuries, and 9.9% of young adult injuries. When treating a patient who presents with injury suffered during surfing, a thorough examination of the HN should be performed. Specific attention should be given to evaluation of lacerations, fractures, internal ear injuries, and concussions. Pediatric and young adult patients are at increased risk of concussion. The majority of surfing injuries can be treated in an outpatient context.

DRUG-INDUCED OTOTOXICITY. AMINOGLYCOSIDE OTOTOXICITY

In modern clinical practice, there are often cases of cochleovestibular disorders induced by the use of drugs. The term "drug-induced ototoxicity" is directly related to the introduction of streptomycin in medical practice and means the ability of drugs or chemicals to cause functional disorders and degeneration of internal ear structures: sensory-epithelial (hair) cells of the organ of Corti, neurons of the eighth cranial nerve (nervus vestibulocochlearis) or auditory centers of the brain. These injuries can be temporary or permanent.

Insights into Inner Ear Function and Disease Through Novel Visualization of the Ductus Reuniens, a Seminal Communication Between Hearing and Balance Mechanisms.

The sensory end-organs responsible for hearing and balance in the mammalian inner ear are connected via a small membranous duct known as the ductus reuniens (also known as the reuniting duct (DR)). The DR serves as a vital nexus linking the hearing and balance systems by providing the only endolymphatic connection between the cochlea and vestibular labyrinth. Recent studies have hypothesized new roles of the DR in inner ear function and disease, but a lack of knowledge regarding its 3D morphology and spatial configuration precludes testing of such hypotheses. We reconstructed the 3D morphology of the DR and surrounding anatomy using osmium tetroxide micro-computed tomography and digital visualizations of three human inner ear specimens. This provides a detailed, quantitative description of the DR's morphology, spatial relationships to surrounding structures, and an estimation of its orientation relative to head position. Univariate measurements of the DR, inner ear, and cranial planes were taken using the software packages 3D Slicer and Zbrush. The DR forms a narrow, curved, flattened tube varying in lumen size, shape, and wall thickness, with its middle third being the narrowest. The DR runs in a shallow bony sulcus superior to the osseus spiral lamina and adjacent to a ridge of bone that we term the "crista reuniens" oriented posteromedially within the cranium. The DR's morphology and structural configuration relative to surrounding anatomy has important implications for understanding aspects of inner ear function and disease, particularly after surgical alteration of the labyrinth and potential causative factors for Ménière's disease.

‘Otolithic’ dizziness

Labyrinth of the inner ear consists of two parts: semicircular canals and vestibulum. Vestibular disorders predominantly associated with vertigo – the feeling of moving of the surrounding objects and oscillopsia. However, vertigo is a result of the damage of ampullar receptors in semicircular canals and their connections with vestibular nuclei in brainstem. At the same time the dysfunction of otoliths system is much more mysterious and unpredictable. Elaboration of new methods of objective assessment of vestibular system provides a wonderful opportunity of the analysis of different components of the peripheral vestibular system including saccular and utricular parts. As a result of such analysis, it was demonstrated that otolithic dysfunction is a common consequence of the most frequent vestibular disorders like Meniere’s disease, benign paroxysmal positional vertigo and vestibular neuritis. It is not clear yet what is the clinical presentation of otolithic dysfunction and how otolithic dysfunction influence the prognosis of common vestibular disorders. It is unknown whether isolated otolithic dysfunction exists, for example in patients with unspecific disequilibrium or dizziness.

The vestibular labyrinth is more robust than previously thought-Lessons from surgical removal of intracochlear schwannoma.

The vestibular labyrinth is more robust than previously thought-Lessons from surgical removal of intracochlear schwannoma.

The Results of Cochlear Implantation in the Inner Ear Malformations.

Cochlear implants are arguably the most successful neural prosthesis today. Cochlear implantation has several difficulties in patients with internal ear anomalies. This study was performed to analyze intraoperative, postoperative findings, and auditory performance of 55 patients who had inner ear malformations and were treated with cochlear implants at Otorhinolaryngology Department of Çukurova University Hospital. Auditory performances were analyzed in 30 of 55 patients. Patients with cochlear anomalies were evaluated as group I, patients with vestibular malformation as group II, and patients with the normal bone labyrinth as group III. Listening progress profiles and meaningful auditory integration scale tests were used to determine performances. Comparison between the listening progress profiles test performance of the groups at 12th and 18th month of group I was significantly lower than other groups (P < .05) and reached at the same level after the 24th month. Comparison between the meaningful auditory integration scale test performance of groups at 24th and 36th month of group I was significantly lower than other groups (P < .05). Perilymph gusher was observed in 3 patients who had incomplete partition I malformation. Oozing was observed in 50% of incomplete partition II patients. Facial nerve traced a variant course in 4 of 55 patients and 6 patients had postoperative meningitis. Initially patients with inner ear anomalies showed that the level of language development was worse than patients with normal bone anatomy. However, it was shown that they both reached the same point as a result. Facial nerve anomaly and meningitis risk is higher in patients with inner ear malformations.

The vestibular labyrinth is more robust than previously thought-lessons from surgical removal of intracochlear schwannoma. German version

The vestibular labyrinth is more robust than previously thought-lessons from surgical removal of intracochlear schwannoma. German version

Clinical and molecular delineation of mandibulofacial dysostosis with microcephaly in six Korean patients: When to consider EFTUD2 analysis?

Mandibulofacial dysostosis with microcephaly (MFDM, OMIM#610536) is an extremely rare genetic syndrome characterised by microcephaly, external ear deformity, hearing loss, and distinct facial appearance, including zygomatic hypoplasia and micrognathia. Occasionally, various malformations in other internal organs, including oesophageal atresia or tracheoesophageal fistula, may lead to life-threatening situations. Haploinsufficiency of EFTUD2 is responsible for MFDM. Here, we present the phenotypic and genetic characteristics of six Korean children who were diagnosed with MFDM by molecular genetic testing. All but one patient had occipitofrontal circumferences below the −2.0 standard deviation score. Micrognathia was identified in all patients. A cleft palate (66.7%) and other facial dysmorphisms, including facial asymmetry (50%) and malar hypoplasia (50%), were also frequently observed. Hearing loss was observed in all patients along with one or more internal and external ear deformities, including ossicular anomalies, auditory canal stenosis, and microtia. Two patients (33.3%) had undergone surgery for tracheoesophageal fistula type C. Most patients were initially misdiagnosed as other better-known syndromes with overlapping characteristics, such as Treacher Collins or CHARGE syndrome. The first three patients were diagnosed using exome sequencing. However, after increased awareness of MFDM in the first three patients, MFDM was considered one of the initial differential diagnoses and could be diagnosed by target gene analysis in the remaining three cases. Thus, we recommend targeted EFTUD2 analysis as the initial workup for the rapid diagnosis of MFDM in patients with facial dysostosis, microcephaly, and otologic problems.

Symptoms: Sudden Hearing Loss and Vertigo

Symptoms: Sudden Hearing Loss and Vertigo

Otitis Media Complications: Labyrinthitis

Background: Otitis media is an inflammation of part or all of the middle ear mucosa, eustachian tube, mastoid antrum and mastoid cells. Otitis media has many complications, one of which is extra-cranial complications such as labyrinthitis. Objective: To know more about labyrithitis and how to treat patients with labyrinthitis in otitis media. Method: This article was written using various sources from scientific journals and medical e-books. Source searches are carried out on the online portal of journal publications such as pdf drive, National Centre for Biotechnology Information/NCBI. Result and Discussion: Labyrinthitis is an inflammatory condition that occurs in the membranous labyrinth of the inner ear which is usually accompanied by vertigo, nausea, vomiting, tinnitus, and hearing loss to hearing loss. Treatment of labyrinthitis caused by viral in outpatients can be done by meeting fluid needs and adequate rest. In labyrinthitis caused by bacteria, topical antibiotic drops should be prescribed. Conclusion: Labyrinthitis is an inflammatory condition that occurs in the membranous labyrinth of the inner ear. Patients with labyrinthitis are usually accompanied by vertigo, nausea, vomiting, tinnitus, and hearing loss to hearing loss. The causes themselves are very diverse, such as viruses, bacteria, autoimmune, and even syphilis.

Low-salt diet increases mRNA expression of aldosterone-regulated transporters in the intermediate portion of the endolymphatic sac.

The endolymphatic sac is a small sac-shaped organ at the end of the membranous labyrinth of the inner ear. The endolymphatic sac absorbs the endolymph, in which the ion balance is crucial for inner ear homeostasis. Of the three sections of the endolymphatic sac, the intermediate portion is the center of endolymph absorption, particularly sodium transport, and is thought to be regulated by aldosterone. Disorders of the endolymphatic sac may cause an excess of endolymph (endolymphatic hydrops), a histological observation in Meniere's disease. A low-salt diet is an effective treatment for Meniere's disease, and is based on the assumption that the absorption of endolymph in the endolymphatic sac abates endolymphatic hydrops through a physiological increase in aldosterone level. However, the molecular basis of endolymph absorption in each portion of the endolymphatic sac is largely unknown because of difficulties in gene expression analysis, resulting from its small size and intricate structure. The present study combined reverse transcription-quantitative polymerase chain reaction and laser capture microdissection techniques to analyze the difference of gene expression of the aldosterone-controlled epithelial Na+ channel, thiazide-sensitive Na+-Cl- cotransporter, and Na+, K+-ATPase genes in the three individual portions of the endolymphatic sac in a rat model. A low-salt diet increased the expression of aldosterone-controlled ion transporters, particularly in the intermediate portion of the endolymphatic sac. Our findings will contribute to the understanding of the physiological function of the endolymphatic sac and the pathophysiology of Meniere's disease.

Cytokines and Inflammation in Meniere Disease.

Meniere disease (MD) is a rare set of conditions associated with the accumulation of endolymph in the cochlear duct and the vestibular labyrinth with a decrease of endocochlear potential. It is considered a chronic inflammatory disorder of the inner ear with a multifactorial origin. The clinical syndrome includes several groups of patients with a core phenotype: sensorineural hearing loss, episodes of vertigo, and tinnitus with a non-predictable course. Genetic factors and the innate immune response seem to play a central role in the pathophysiology of the condition. Autoimmune MD should be diagnosed if a patient fulfills the diagnostic criteria for MD and one of the following autoimmune disorders: autoimmune thyroid disease, psoriasis, autoimmune arthritis, ankylosing spondylitis, or systemic lupus erythematosus. We summarize the evidence to support autoimmune MD as an endophenotype in bilateral MD associated with the allelic variant rs4947296 and nuclear factor-kappa B (NF-κB)-mediated inflammation, the role of cytokines (particularly interleukin-1β and tumor necrosis factor-α) in defining a subset of patients with autoinflammation, and the potential role of cytokines as biomarkers to distinguish between patients with MD and vestibular migraine. Finally, we also introduce a list of potential drugs that could regulate the immune response in MD with potential for repurposing in clinical trials.

Role of computed tomography and MRI in children with sensorineural hearing loss

Background and aim Given the tremendous developments in visualization science, there are many congenital and acquired internal ear anomalies that have no radiological signs. However, visualization is an important instrument for the assessment of congenital and acquired sensory neural hearing loss (SNHL) triggers. The aim is to assess the value of multidetector computed tomography (MDCT) and MRI in internal ear abnormality detection in children with SNHL. Patients and methods This study included 100 children of 10 years or younger with SNHL. The cochlea, the vestibule, the three semicircular canals, the endolymphatic duct, and the internal acoustic canal. In addition, three-dimensional DRIVE MRI gives good demonstration of all four nerves within the internal acoustic canal. Results A total of 46 malformations were detected in only 25 patients with 42 malformations that were detected in MDCT examination presenting 91% of all abnormalities, while in MRI examination, 44 malformations are detected presenting 96% of all abnormalities. MDCT showed accuracy, sensitivity, and specificity 96.7, 91.3, and 100%, respectively, while for MRI, it showed accuracy, sensitivity, and specificity 98.3, 95.7, and 100%, respectively. Conclusion Imaging plays an important role in the workup of children with SNHL. Therefore, it is imperative to define the etiology of hearing loss. High-resolution CT and MRI modalities are the two principal radiological investigations to detect various pathologies in the inner ear. ‘Dual-modality imaging’ using both MRI and CT, made sense for many patients because the dual-scan approaches detect abnormalities related to hearing loss that would not otherwise be found using either modality alone.

Sensorineural Hearing Loss and its Management through Ayurveda – A Case Study

Hearing is one of the primary modes of communication. Hearing loss is one of the most common sensory deficit and it comprises a broad spectrum of clinical presentations. Impairment of hearing occurs when there is inability for sounds to be transmitted through or interpreted by our brain. Disorders of internal ear and auditory nerve will lead to sensorineural hearing loss (SNHL). The management of the SNHL is conventionally with rehabilitation with hearing aids and cochlear implants, and the option for pharmacologically treating the hearing impairment is limited. Hence there is need to lookback to our classical methods as told by our Acharyasfor treating SNHL. In Ayurveda, hearing loss can be correlated to badhirya,wherein many therapeutic procedures, formulations have been told by our acharyas for the successful management of badhirya. So in the present case an attempt is made to treat a case of SNHL through ayurvedatreatment strategy

Bacterial Isolates and Antibiotic Susceptibility of Ear Infections in Al-Kindy Teaching Hospital, Baghdad, Iraq

Background: Ear infections can manifest in many forms depending on site of infection whether external, middle or internal ear and the culprit pathogen whether viral, bacterial or fungal. Acute middle ear infections are usually accompanied by aural discharge. Objective: 1. To get an overview on the bacterial pathogens involved in ear infections. 2. To assess the antibiotic resistance of bacterial pathogens. Methods: A cross sectional study conducted in Al-Kindy Teaching Hospital / Baghdad /Iraq. Swabs taken from 225 patients suffering from aural discharge were tested for culture and sensitivity for the duration of two years 2018-2019. Aural discharge is cultured by inoculating it into blood, MacConkey agar, chocolate agars and Sabouraud agar (for fungi). Then the antibiotic susceptibility and resistance is assessed by (Kirby-Bauer Method). Results: Then, by analyzing the percentage of pathogens involved in ear infections we have found that the highest percentage is for Pseudomonas aeruginosa (51%), followed by Staph, aureus (20%), Proteus vulgaris (11%). Discussion: Cefotaxime, which was known to be an efficient antibiotic against pseudomonas previously, has lost its effectiveness. Similarly, gentamycin is no longer effective against E.coli. Conclusion: Choosing the proper antibiotic in any bacterial infection is of tremendous importance. However, reassessment of antibiotic resistance profiles is vital and should be regarded as a routine task on regular intervals.

Ménière’s disease and chronic cerebrovascular diseases

Ménière’s disease (MD) is an idiopathic inner ear disease, which is characterized by noise in the ears, periodic attacks of vertigo and the development of sensorineural hearing loss. MD is characterized by endolymphatic hydrops – an increase in the volume of endolymph that fills the membered labyrinth of the inner ear. Currently highlighted subtypes MD. The first subtype meets most often and is characterized by classical manifestations of MD. The second subtype is characterized by the development of sensorineural hearing loss, to which only after a long time are joined by the episodes of dizziness. The third subtype of MD includes family cases of the disease. The fourth and fifth subtypes of MD is observed in patients with migraine and autoimmune diseases. The diagnosis of definite MD is based on the 2 or more spontaneous episodes of vertigo with each lasting 20 minutes to 12 hours, low-to medium-frequency sensorineural hearing loss in one ear, fluctuating aural symptoms (fullness, hearing, tinnitus) located in the affected ear, and lack of data for other reasons for dizziness. There are no effective treatment for auditory disorders MD, therapy is aimed at preventing dizziness attacks. The first line of MD’s therapy includes a dietary salt restriction, the use of betahistine and diuretics. Betahistine (Betaserc) is usually used in a daily dose of 48 mg for 3–6 months to reduce the frequency of vertigo. For long-term treatment, it is convenient to use a betahistine modified-released (Betaserc Long) 48 mg, taken once a day. With the ineffectiveness of conservative therapy, other methods of therapy are possible: intratympanic administration of corticosteroids or gentamicin, labyrinthectomy or vestibular neurectomy. Unfortunately, many patients suffering from BM mistakenly makes a diagnosis of cerebrovascular disease, vertebrobasilar insufficiency, cervical osteochondrosis. Diagnostic errors are usually caused by the fact that the patients with MD are not conducted audiometry, vestibular tests, and the signs of cerebral microangiopathy identified when MRI brain are mistakenly regarded as confirmation of vascular dizziness genesis.

Pathways and Pathogenesis of Hearing Deficits, Tinnitus, and Vertigo in COVID-19.

COVID-19 has been shown to affect the ear and has led to hearing deficits, tinnitus, and vertigo. Very little is known regarding the mechanisms and targets of SARS-CoV-2 that cause the above symptoms. Anatomical extensions from the areas of viral loads to the middle ear appear to enable the SARS-CoV-2 to cause either an inflammatory response or a direct effect on the lining epithelium leading to temporary hearing and equilibrium-related symptoms in COVID-19. Herein the anatomical continuity from the areas of viral loads to the middle and internal ear is debated to uncover the possible covert routes used by SARS-CoV-2 to affect the hearing and equilibrium in COVID-19.

A case series shows independent vestibular labyrinthine function after major surgical trauma to the human cochlea

BackgroundThe receptors for hearing and balance are housed together in the labyrinth of the inner ear and share the same fluids. Surgical damage to either receptor system was widely believed to cause certain permanent loss of the receptor function of the other. That principle, however, has been called into question because there have been anecdotal reports in individual patients of at least partial preservation of cochlear function after major surgical damage to the vestibular division and vice versa.MethodsWe performed specific objective vestibular function tests before and after surgical trauma (partial or subtotal cochlear removal) for treatment of intracochlear tumors in 27 consecutive patients in a tertiary referral center. Vestibular function was assessed by calorics (low-frequency response of the lateral semicircular canal), vestibulo-ocular reflex by video head impulse test (vHIT) of the three semicircular canals, cervical and ocular vestibular evoked myogenic potentials (cVEMP, saccule and oVEMP, utricle). Preoperative and postoperative distributions were compared with paired t-tests.ResultsHere we show that there was no significant difference between pre- and post-operative measures for all tests of the five vestibular organs, and that after major surgical cochlear trauma, the vestibular receptors continue to function independently.ConclusionsThese surprising observations have important implications for our understanding of the function and the surgery of the peripheral auditory and vestibular system in general and open up new possibilities for the development, construction and evaluation of neural interfaces for electrical or optical stimulation of the peripheral auditory and vestibular nervous system.