Superior Canal Dehiscence Research Articles

Vestibular evoked myogenic potentials

Vestibular Evoked Myogenic Potentials (VEMP) are commonly recorded in patients experiencing vertigo or chronic instability. This test evaluates the patient's otolith function and is often combined with both Videonystagmography and Video Head Impulse Test. VEMP is a simple, reproducible test, in the absence of any pre-existing conductive hearing loss. Cervical VEMP explore both saccular function and the inferior vestibular nerve, whereas ocular VEMP assess utricular function and the superior vestibular nerve. In combination with previously described tests, VEMP allows characterization of vertigo and provides support for the diagnosis of superior semicircular canal dehiscence syndrome, Menière's disease, vestibular neuritis, vestibular schwannoma or idiopathic bilateral vestibulopathy. A good knowledge of these electrophysiological tests is essential in order to precisely assess the presence or absence of vestibular function impairment. We describe the test recording technique and the most common pitfalls in interpretation of the results. We then outline the results observed in various diseases impacting vestibular function.

Ambient pressure tympanometry in the workup of patulous eustachian tube and neurotologic disorders.

In contrast to previous reports, respiration-synchronous APT wave patterns display low sensitivity (53.3%) in our retrospective cohort of 15 PET ears, as diagnosed by characteristic symptoms and otoscopy. In 327 non-PET ears, the largest cohort of non-PET ears evaluated to date, respiration-synchronous APT wave patterns demonstrate high specificity for PET (93.9%), consistent with previous literature. APT performed solely at rest and with ipsilateral nostril respiration displays similar sensitivity for PET as the full battery of respiratory maneuvers. Pulse-synchronous wave patterns at rest may suggest an alternative neurotologic diagnosis requiring further workup, such as superior semicircular canal dehiscence. Ambient pressure tympanometry is a rapid, simple and widely available tool that can be integrated into general otolaryngology clinics and warrants further study in the evaluation of PET and neurotologic disorders.

A curious case of bilateral superior semicircular canal dehiscence in a scenographer

The superior semicircular canal dehiscence syndrome (SSCDS) was first reported by Lloyd Minor and colleagues back in 1998. Since then, many patients have been diag­nosed with this syndrome and the diagnostic and treatment pro­­to­­cols are constantly being developed and refined. The patho­gno­mo­nic signs of this disease, like vertigo induced by loud sounds or pressure delivered into the external ear, are well known amongst audiologists and ENT doctors alike. Despite the fact that the Bárány Society has proposed diag­no­sis criteria for this disease and the technological progress in the domain of medical imaging is constantly providing doc­tors with better means to assess patients, SSCDS is still a fle­eting concept, with semicircular canal dehiscence present in asymptomatic individuals or with bilateral bone defects which produce oscillopsia and mimic a bilateral vestibular loss at times.

İdiyopatik İntrakraniyal Hipertansiyon Hastalarında Süperior Semisirküler Kanal Dehisansı: Ön Rapor

İdiyopatik İntrakraniyal Hipertansiyon Hastalarında Süperior Semisirküler Kanal Dehisansı: Ön Rapor

Clinical and diagnostic criteria and differential diagnosis in the first and second stages of the development of Ménière's disease - A modern view of the problem

The results of a comprehensive examination of 82 patients with clinical signs of definite Ménière's disease, unilateral lesion and confirmed by extratympanic electrocochleography endolymphatic hydrops are presented. The results of the study showed that only 38% of patients had cochleovestibular syndrome due to Ménière's disease. In 45% of patients, Ménière's disease was combined with other diseases: benign paroxysmal positional vertigo, vestibular migraine, persistent postural-perceptual dizziness, superior semicircular canal dehiscence. In 17% of patients cochleovestibular syndrome was due to other reasons: vestibular migraine, tumor of the posterior cranial fossa, superior canal dehiscence syndrome, Cogan's syndrome, enlarged vestibular aqueduct, otosclerosis. Complaints, medical history of the disease and life, brain MRI, temporal bone CT and pure tone audiometry in dynamics are important in suspected Ménière's disease. For 1 and 2 Ménière's disease stages the most important characteristic are: progressive unilateral sensorineural hearing loss and reduced slow faze velocity values of caloric nystagmus in dynamics, mainly in warm response if attacks of vertigo is maintain; normal head impulse test between vertigo attacks and pathological result of this test in attack of vertigo with the normalization of gain during the first day.

A Case of Superior Canal Dehiscence Syndrome Misdiagnosed as Patulous Eustachian Tube

A Case of Superior Canal Dehiscence Syndrome Misdiagnosed as Patulous Eustachian Tube

A case of superior canal dehiscence syndrome

A case of superior canal dehiscence syndrome

Pulsatile Tinnitus in Superior Semicircular Canal Dehiscence Cured by Endovascular Coil Occlusion of the Superior Petrosal Sinus.

Pulsatile Tinnitus in Superior Semicircular Canal Dehiscence Cured by Endovascular Coil Occlusion of the Superior Petrosal Sinus.

Analysis of temporal bone thickness outside of the petrous temporal bone between superior semicircular canal dehiscence and normal patients

BackgroundSSCD is a rare inner ear disorder. This study aims to compare the thickness of the temporal bone beyond the petrous portion between healthy subjects and those with SSCD to determine whether the etiopathology of SSCD is localized to the petrous temporal bone or generalized to other parts of the temporal bone. MethodsA retrospective chart review of electronic medical records from September 2011 to February 2018 was conducted at a single-institution study at the University of California, Los Angeles. Participants were divided into two groups: Group 1 had a confirmed diagnosis of SSCD, while Group 2 had no known ear or temporal bone pathology. Participants’ high-resolution coronal and axial temporal bone computed tomography scans were analyzed. Regions within the temporal bone were measured and compared between the two groups. ResultsA total of 262 scans were included. Group 1 consisted of 103 scans, while Group 2 consisted of 159 scans. There was no statistically significant difference in the thickness of temporal bones between patients diagnosed with SSCD and patients without otologic disease. ConclusionThe results suggest that the etiology of SSCD is limited to the petrous portion of the temporal bone. SSCD may be unrelated to a larger process of global temporal bone degeneration. Additional clinical screening for regions outside the petrous temporal bone is not warranted unless SSCD patients present with symptoms characteristic of other temporal bone pathologies.

Concurrent superior semicircular canal dehiscence and endolymphatic hydrops: A novel case series

IntroductionSuperior semicircular canal dehiscence (SSCD) is characterized by CT-confirmed bony erosion over the superior semicircular canal, creating vestibular and auditory symptoms. Endolymphatic hydrops (EH) is characterized by an MRI-confirmed excess of endolymph within the scala media that distorts the membranous labyrinth. While there is overlap in symptoms, the two diseases result from different pathophysiologies and require different interventions. Presentation of casesA retrospective chart review was conducted at the University of California, Los Angeles on a database of 270 adult SSCD patients, gathered between March 2011 and February 2020. A review of clinical notes, post-operative findings, and imaging was performed for 16 patients who had both CT-confirmed SSCD and an MRI of the internal auditory canal (IAC). Three cases of concurrent SSCD and EH were identified. Medical and surgical history, symptom progression pre- and post-operatively, and treatment outcomes were gathered. One patient’s symptoms were resolved via mycophenolate mofetil, another’s via hydrochlorothiazide, and the third’s via hydrochlorothiazide and bilateral hearing aids. DiscussionPost-surgical persistence of SSCD symptoms that are mutually shared with EH is the strongest indicator that a physician should investigate for concurrent EH. VEMP and audiogram testing in these cases can be misleading and should not be relied on as rule-in or rule-out tests. ConclusionConcurrent SSCD and EH is a rare but treatable entity. Physicians should consider ordering an MRI of the IAC if SSCD patients’ symptoms persist or recur after a successful surgery.

Transtemporal Venous Decompression for Idiopathic Venous Pulsatile Tinnitus.

Objective To evaluate the clinical characteristics and present surgical outcomes of transtemporal venous decompression technique in the treatment of pulsatile tinnitus (PT). Study Design This is a prospective cohort study. Setting This study was done at the tertiary private neurotologic skull base clinic. Participants The primary author, between March 2012 and February 2013, evaluated 55 patients with the complaint of PT. Seven out of the 55 patients were diagnosed with severe, unrelenting idiopathic pulsatile tinnitus (IPT), and were placed into the study. These seven patients had temporal bone computed tomography, magnetic resonance imaging, arteriogram, videonystagmography, electrocochleography, and lumbar puncture based on the symptoms. All the seven patients underwent transtemporal venous decompression surgery. Main Outcome Measure Resolution of PT was determined as the primary outcome measure. Results Six out of seven patients had complete resolution of their PT immediately after surgery and at 3 to 4 years follow-up. One patient developed intracranial hypertension after 3 months requiring ventriculoperitoneal shunt, which resolved PT as well. No complications occurred. Conclusion A significant subset of the PT patient population has known reversible causes. The more common includes conductive hearing loss, superior canal dehiscence, benign intracranial hypertension, jugulosigmoid venous anomalies, stapedial myoclonus, etc. There exists a subset of patients who have IPT. Transtemporal venous decompression is a surgical technique that can be employed to give patients with IPT long-term relief.

Complete Restored Hearing Loss after Excessive Nose Blowing with Various CT Findings

A perilymphatic fistula (PLF) is defined as leakage of perilymph with several possible causes such as superior canal dehiscence through trauma, temporal bone fracture, or sudden pressure change (e.g., skydiving or scuba diving). Pneumolabyrinth can result from temporal bone fracture after trauma, or sudden pressure change in the middle ear or cerebrospinal fluid, such as excessive nose blowing or Valsalva maneuver. A PLF and pneumolabyrinth may occur without trauma, associated with a sudden pressure change in the middle ear. We report two cases of PLF followed by pneumolabyrinth and one case of suspicious PLF without pneumolabyrinth after excessive nose blowing. All three cases were diagnosed as having sensorineural hearing loss and the patients recovered completely after conservative treatment. We report various CT findings of pneumolabyrinth and PLF, from normal CT findings to air pockets in the labyrinth and soft tissue density around the stapes.

How to do and why perform the skull vibration-induced nystagmus test

The skull vibration-induced nystagmus test (SVINT) is a global vestibular test stimulating otoliths and semicircular canals at a frequency of 100Hz, not modified by vestibular compensation, which may reveal vibration-induced nystagmus (VIN). Bone-conducted vibration applied to the mastoid processes and the vertex instantaneously induces predominantly low-velocity (∼10°/s) horizontal nystagmus, with rapid phases beating away from the affected side in patients with unilateral vestibular loss (UVL). VIN starts and stops immediately with stimulation, is continuous, reproducible, beats in the same direction irrespective of which mastoid process is stimulated, with no or little habituation. The SVINT acts like a vestibular Weber test. In peripheral UVL, the SVINT is a good marker of vestibular asymmetry and demonstrates pathological nystagmus beating towards the healthy side in 90% of cases of vestibular neuritis, 71% of cases of Menière's diseases and 44 to 78% of vestibular schwannomas. In superior semicircular canal dehiscence, VIN usually beats towards the affected side due to facilitation of bone conduction related to the presence of a third window. Stimulation of the vertex is more effective than in UVL patients, with sensitivity extending to higher frequencies, up to 700Hz. Observation of vibration-induced nystagmus then reveals equally represented vertical, torsional, and horizontal components beating towards the affected ear, suggesting dominant, but not exclusive, stimulation of the dehiscent superior semicircular canal.

Radiologically-proven New Development of Superior Semicircular Canal Dehiscence Associated With Development of Superior Semicircular Canal Dehiscence Syndrome

This report describes a case of development of radiologic superior semicircular canal dehiscence and reviews the literature for pertinent clinical and radiologic findings in patients with superior semicircular canal dehiscence syndrome (SCDS). A 28-year-old man presented with auditory and vestibular symptoms of SCDS and underwent a high-resolution temporal bone computed tomography scan that showed frank dehiscence of the right superior semicircular canal. Diagnosis of SCDS was further verified with audiometric and cervical vestibular-evoked myogenic potential (cVEMP) thresholds. The patient had previously undergone a computed tomography scan 12 years prior for work-up of sudden sensorineural hearing loss that showed no evidence of superior semicircular canal dehiscence bilaterally. A combination of diagnostic and therapeutic interventions was conducted consisting of preoperative audiometric and cVEMP thresholds, followed by middle fossa craniotomy for surgical repair of the dehiscence. Postoperative audiometric and cVEMP thresholds and symptomatic improvement of SCDS after surgical repair of the dehiscence. The patient reported resolution of his clinical symptoms after surgical repair of the dehiscence. Postoperative cVEMP thresholds improved to the normal range and the mild low-frequency conductive hearing loss resolved. To our knowledge, this case report is the first description of radiologically proven new development of superior canal dehiscence. Further prospective studies that include serial imaging examinations may help with visualizing and understanding the temporal evolution of superior canal dehiscence, and better elucidate the relationship between development/ progression of superior canal dehiscence and onset of clinical symptoms.

Association between superior semicircular canal dehiscence and other dehiscences in temporal bone.

The study of the association between superior semicircular canal and other dehiscences in the temporal bone. We have studied computed tomography of radiologically diagnosed people with superior or posterior semicircular canal dehiscences, in four health centres. In addition, we have studied one isolated human temporal bone, one skull and one cadaver head belonging to the collection of the Department of Human Anatomy and Histology of the University of Zaragoza that had dehiscence in the superior semicircular canal. The most frequent association that we observed was between superior semicircular canal dehiscence and tegmen tympani dehiscence (37.33%). Three cases (two clinical cases and one isolated temporal bone) showed multiple associated dehiscences (tegmen tympani, mastoid antrum, posterior semicircular canal, internal auditory canal, glenoid cavity, tympanum bone and geniculate ganglion) associated with superior semicircular canal dehiscence. When the superior semicircular canal dehiscence is associated to other in the petrous bone (tegmen tympani, mastoid antrum, posterior semicircular canal, internal auditory canal) could be grouped into the same syndrome called "otic capsule syndrome", since they have the same origin and common aetiology (otic capsule).

Beyond Tympanomastoidectomy: A Review of Less Common Postoperative Temporal Bone CT Findings.

Postoperative temporal bone imaging after surgical procedures such as ossiculoplasty, tympanomastoidectomy, cochlear implantation, and vestibular schwannoma resection is often encountered in clinical neuroradiology practice. Less common otologic procedures can present diagnostic dilemmas, particularly if access to prior operative reports is not possible. Lack of familiarity with the less common surgical procedures and expected postoperative changes may render radiologic interpretation challenging. This review illustrates key imaging findings after surgery for Ménière disease, superior semicircular canal dehiscence, temporal encephalocele repairs, internal auditory canal decompression, active middle ear implants, jugular bulb and sigmoid sinus dehiscence repair, and petrous apicectomy.

Prospective Analysis of an Evidence-Based Symptom Set in Superior Canal Dehiscence Syndrome.

Superior canal dehiscence syndrome (SCDS) is characterized by a defect in the bone overlying the superior semicircular canal. This third mobile window generates an abnormal low-impedance pathway for sound/pressure transmission into the inner ear resulting in the characteristic symptoms. To perform a prospective analysis of symptoms in patients with SCDS. An aggregated symptom set was studied prospectively and compared with a healthy control group. The 31 items inquired about the presence and severity of symptoms. Initial comparison between both groups was performed using the Kolmogorov-Smirnov test and nonparametric Mann-Whitney U test. For analysis of the internal consistency, the Cronbach's alpha coefficient was determined. Finally, the prevalence of symptoms obtained in the present study was compared to the prevalence of symptoms obtained as part of a recent retrospective systematic review. Responses from the 29 patients with SCDS in the case group and the 58 healthy controls were not normally distributed. Those with SCDS had a higher prevalence and more severe symptoms for almost all items. The Cronbach's alpha coefficient of 0.969 indicates an excellent internal consistency. The prospective prevalence of most symptoms was higher than the retrospective prevalence reported earlier. SCDS causes a variety of vestibular and auditory symptoms. This prospective study demonstrates that their prevalence and severity are higher than reported previously. This symptom set demonstrates excellent internal consistency and will serve as a foundation toward developing a disease-specific patient-reported outcome measure for SCDS. NA.

Vestibular-evoked myogenic potentials: principle and clinical findings

Vestibular-evoked myogenic potentials (VEMPs) are useful for evaluating the vestibulocollic reflex arising mostly from the saccule and the vestibuloocular reflex originating from the utricle. VEMPs can vary with the characteristics of the applied stimuli and the effects of aging and diseases. VEMPs have been found to be useful for diagnosing superior canal dehiscence, but their usefulness for other clinical disorders remains unclear. This review discusses the principles of VEMP tests and summarizes the findings for VEMPs in common vestibular disorders. Key Words: Vestibular-evoked myogenic potentials · Saccule and utricle · Vestibular disorders.

Bone-Conducted oVEMP Latency Delays Assist in the Differential Diagnosis of Large Air-Conducted oVEMP Amplitudes.

Background: A sensitive test for Superior Semicircular Canal Dehiscence (SCD) is the air-conducted, ocular vestibular evoked myogenic potential (AC oVEMP). However, not all patients with large AC oVEMPs have SCD. This retrospective study sought to identify alternate diagnoses also producing enlarged AC oVEMPs and investigated bone-conducted (BC) oVEMP outcome measures that would help differentiate between these, and cases of SCD.Methods: We reviewed the clinical records and BC oVEMP results of 65 patients (86 ears) presenting with dizziness or balance problems who underwent CT imaging to investigate enlarged 105 dB nHL click AC oVEMP amplitudes. All patients were tested with BC oVEMPs using two different stimuli (1 ms square-wave pulse and 8 ms 125 Hz sine wave). Logistic regression and odds ratios were used to determine the efficacy of BC oVEMP amplitudes and latencies in differentiating between enlarged AC oVEMP amplitudes due to dehiscence from those with an alternate diagnosis.Results: Fifty-three ears (61.6%) with enlarged AC oVEMP amplitudes were identified as having frank dehiscence on imaging; 33 (38.4%) had alternate diagnoses that included thinning of the bone covering (near dehiscence, n = 13), vestibular migraine (n = 12 ears of 10 patients), enlarged vestibular aqueduct syndrome (n = 2) and other causes of recurrent episodic vertigo (n = 6). BC oVEMP amplitudes of dehiscent and non-dehiscent ears were not significantly different (p > 0.05); distributions of both groups overlapped with the range of healthy controls. There were significant differences in BC oVEMP latencies between dehiscent and non-dehiscent ears for both stimuli (p < 0.001). A prolonged n1 125 Hz latency (>11.5 ms) was the best predictor of dehiscence (odd ratio = 27.8; 95% CI:7.0-111.4); abnormal n1 latencies were identified in 79.2% of ears with dehiscence compared with 9.1% of ears without dehiscence.Conclusions: A two-step protocol of click AC oVEMP amplitudes and 125 Hz BC oVEMP latency measures optimizes the specificity of VEMP testing in SCD.

High-Resolution Three Dimensional MRI Findings After Plugging Surgery for Superior Semicircular Canal Dehiscence: A Case Report

: Superior semicircular canal dehiscence (SSCD) is known as abnormal communication of the superior semicircular canal (SCC) to the intracranial space secondary to a bony defect in the canal. Patients who are subjected to surgical repair usually have intractable symptoms, and recently, plugging of SCC using a transmastoid approach has been widely recommended. In this report, we describe a case of incomplete plugging for SSCD in a 37-year-old woman, along with the high-resolution three dimensional magnetic resonance imaging (3D MRI) findings using Pöschl view reconstruction. Postoperative MRI of 3D T2-wieghted sampling perfection with application optimized contrasts using different flip angle evolution (SPACE) Pöschl plane demonstrated an incomplete plugging of the SCC with partially visible perilymphatic fluid in the posterior limb above the common crus. A 3D fluid-attenuated inversion recovery (FLAIR) sequence showed an enhancement involving the vestibule and SCC, suggesting labyrinthitis. Although there are few reports about incomplete plugging for SSCD, this case could demonstrate postoperative status and complication after plugging of SSCD using a high-resolution 3D MRI sequences with Pöschl view reconstruction.