Electrocochleography Results in Patients With Bilateral Vestibular Paresis and Sound- or Pressure-Induced Horizontal Nystagmus.

OBJECTIVE: To describe the electrocochleography (ECochG) findings in patients with bilateral vestibular paresis and sound- and/or pressure-induced horizontal nystagmus. DESIGN: Retrospective case series. SETTING: Tertiary care center. PATIENTS: Three adult patients with bilateral vestibular paresis and sound- and/or pressure-induced horizontal nystagmus were evaluated from 2012 to 2016. MAIN OUTCOME MEASURE: All patients underwent ECochG, vestibular evoked myogenic potential (VEMP) testing, bithermal caloric testing, rotary chair testing, audiometric testing, and temporal bone computed tomography (CT). For ECochG, the summating potential (SP) to action potential (AP) ratio was determined. RESULTS: All patients had normal temporal bone CT, reduced caloric responses bilaterally, decreased gain on rotary chair, and abnormal ECochG. For two subjects, the SP/AP was elevated bilaterally. One subject had unilateral SP/AP elevation. Cervical VEMPs were present in all subjects, but at reduced thresholds in two subjects. CONCLUSION: SP/AP elevation was found in all three patients with the syndrome of bilateral vestibular paresis and/or sound- or pressure-induced horizontal nystagmus. As the etiology of this syndrome remains unclear, understanding the basis for abnormal ECochG may shed insight into the pathophysiology of this condition.

Superior Canal Dehiscence Syndrome Affecting 3 Families.

Importance: Superior canal dehiscence syndrome (SCDS) is an increasingly recognized cause of hearing loss and vestibular symptoms, but the etiology of this condition remains unknown. Objective: To describe 7 cases of SCDS across 3 families. Design, Setting, and Participants: This retrospective case series included 7 patients from 3 different families treated at a neurotology clinic at a tertiary academic medical center from 2010 to 2014. Patients were referred by other otolaryngologists or were self-referred. Each patient demonstrated unilateral or bilateral SCDS or near dehiscence. Interventions: Clinical evaluation involved body mass index calculation, audiometry, cervical vestibular evoked myogenic potential testing, electrocochleography, and multiplanar computed tomographic (CT) scan of the temporal bones. Zygosity testing was performed on twin siblings. Main Outcomes and Measures: The diagnosis of SCDS was made if bone was absent over the superior semicircular canal on 2 consecutive CT images, in addition to 1 physiologic sign consistent with labyrinthine dehiscence. Near dehiscence was defined as absent bone on only 1 CT image but with symptoms and at least 1 physiologic sign of labyrinthine dehiscence. Results: A total of 7 patients (5 female and 2 male; age range, 8-49 years) from 3 families underwent evaluation. Family A consisted of 3 adult first-degree relatives, of whom 2 were diagnosed with SCDS and 1 with near dehiscence. Family B included a mother and her child, both of whom were diagnosed with unilateral SCDS. Family C consisted of adult monozygotic twins, each of whom was diagnosed with unilateral SCDS. For all cases, dehiscence was located at the arcuate eminence. Obesity alone did not explain the occurrence of SCDS because 5 of the 7 cases had a body mass index (calculated as weight in kilograms divided by height in meters squared) less than 30.0. Conclusions and Relevance: Superior canal dehiscence syndrome is a rare, often unrecognized condition. This report of 3 multiplex families with SCDS provides evidence in support of a potential genetic contribution to the etiology. Symptomatic first-degree relatives of patients diagnosed with SCDS should be offered evaluation to improve detection of this disorder.

Refractory Positional Vertigo With Apogeotropic Horizontal Nystagmus After Labyrinthitis: Surgical Treatment and Identification of Dysmorphic Ampullae.

OBJECTIVES: To describe the rationale, intraoperative details, and histopathologic findings discovered when treating an unusual case of apogeotropic horizontal canal positional vertigo with a transmastoid labyrinthectomy. PATIENT: A single case report. INTERVENTION: Therapeutic. MAIN OUTCOME MEASURES: Resolution of apogeotropic nystagmus and improvement of positional vertigo. RESULTS: The apogeotropic variant of horizontal canal positional vertigo can be a difficult entity to treat. This report describes a patient who developed profound sensorineural hearing loss and vertigo after an acute left labyrinthitis. Ten months later, she developed vertigo with apogeotropic positional nystagmus involving the left horizontal semicircular canal. Particle repositioning maneuvers and vestibular physical therapy were unsuccessful. In addition, she developed intermittent positional vertigo affecting the ipsilateral vertical semicircular canals. Given the persistence of her vertigo, multiple canal involvement, and patient preference for definitive treatment, a transmastoid labyrinthectomy was performed. Intraoperatively, the ampulla of the horizontal canal as well as that of the other canals was grossly abnormal as later confirmed on histology. After surgery, her apogeotropic nystagmus and vertigo resolved, and her balance ability gradually improved to a highly functional level. CONCLUSION: This case illustrates a unique form of positional vertigo that developed and persisted after acute labyrinthitis. Conservative measures were unsuccessful and a transmastoid labyrinthectomy documented dense inflammatory tissue involving all three ampullae. We postulate that the post-labyrinthitic inflammatory changes resulted in mass loading of the membranous ampullae, causing abnormal nystagmus patterns and positional vertigo, which resolved after the labyrinthectomy.

Nystagmus discordance with 2-dimensional videonystagmography in posterior semicircular canal benign paroxysmal positional vertigo.

OBJECTIVE: The Dix-Hallpike test is a standard component of the videonystagmography test battery and can diagnose posterior semicircular canal benign paroxysmal positional vertigo. The purpose of this study is to determine the prevalence of discordant, equivocal, and concordant nystagmus tracings in active posterior semicircular canal benign paroxysmal positional vertigo when compared directly with the eye video. STUDY DESIGN: Case series with chart review of patients diagnosed with posterior semicircular canal benign paroxysmal positional vertigo by 2-dimensional videonystagmography from August 1, 2007, to August 1, 2012. SETTING: A tertiary vestibular test laboratory. SUBJECTS AND METHODS: Ninety-six adults (4 had bilateral involvement) with posterior semicircular canal benign paroxysmal positional vertigo were included. A total of 100 videos with accompanying videonystagmography tracings were reviewed to determine nystagmus trajectory as well as globe position. Descriptive statistics were used to describe prevalence. Fisher exact test was used to compare proportions. RESULTS: Sixty-two percent of cases involved benign paroxysmal positional vertigo of the right posterior semicircular canal, while 38% involved the left posterior semicircular canal. The prevalence of discordant, equivocal, and concordant tracings was 65% (65/100), 29% (29/100), and 6% (6/100). All tracing errors involved the horizontal channel. There was no association between tracing accuracy and the ear of involvement or globe position (P > .05). CONCLUSIONS: Two-dimensional videonystagmography tracings are not reliable for identifying nystagmus trajectory in posterior semicircular canal benign paroxysmal positional vertigo.

Surgical treatment of hearing loss when otosclerosis coexists with superior semicircular canal dehiscence syndrome.

OBJECTIVE: Document a case of bilateral otosclerosis with coexisting bilateral superior semicircular canal dehiscence syndrome and the treatment of hearing loss in this setting. PATIENT: A 33-year-old woman presented with bilateral mixed hearing loss; worse in the left ear. This was gradual in onset, and she denied dizziness. Computerized tomographic scan revealed fenestral otosclerosis and a large dehiscence of the superior semicircular canal bilaterally. She declined amplification. INTERVENTION: Sequential laser-assisted stapedotomy with insertion of a Kurz titanium CliP Piston prosthesis. MAIN OUTCOME MEASURE: Comparison of audiovestibular symptoms, hearing thresholds, and neurodiagnostic testing results preoperatively and postoperatively. RESULTS: Hearing improved bilaterally with closure of the air-bone gaps at most frequencies, and she has not had permanent vestibular symptoms. Postoperative follow-up time is 37 months for the left ear and 13 months for the right ear. CONCLUSION: When otosclerosis and superior semicircular canal dehiscence syndrome coexist and hearing loss is the dominant symptom, stapes surgery can be effective for improving hearing without permanent vestibular symptoms.

Tullio phenomenon in superior semicircular canal dehiscence syndrome.

Tullio phenomenon refers to eye movements induced by sound.(1) This unusual examination finding may be seen in superior semicircular canal dehiscence (SSCD) syndrome.(2) This disorder is due to absent bone over the superior semicircular canal (figure). Patients complain of dizziness triggered by loud sound, aural fullness, autophony, and pulsatile tinnitus. When Tullio phenomenon exists in SSCD syndrome, the patient develops a mixed vertical-torsional nystagmus in which the slow phase rotates up and away from the affected ear (video on the Neurology® Web site at Neurology.org). This pattern of nystagmus aligns in the plane of the dehiscent semicircular canal and is due to excitation of its afferent nerves.

Canal switch after canalith repositioning procedure for benign paroxysmal positional vertigo.

Canal switch is a complication following canalith repositioning procedure (CRP) for posterior canal benign paroxysmal positional vertigo (BPPV). Instead of being returned to the utricle, the loose otoconia migrate into the superior or horizontal semicircular canal. Patients remain symptomatic, and treatment can be ineffective unless the switch is recognized and additional repositioning maneuvers directed toward the appropriate semicircular canal are performed. This report provides the first videographic documentation of canal switch involving conversion of unilateral posterior semicircular canal BPPV to geotropic horizontal canalithiasis.

Hennebert's sign in superior semicircular canal dehiscence syndrome: a video case report.

Superior semicircular canal dehiscence (SSCD) syndrome has been called the great otologic mimicker because its presentation overlaps with otosclerosis, Meniere's disease, perilymphatic fistula, and patulous eustachian tube. A valuable examination finding that can help distinguish SSCD syndrome from other pathologic conditions is the presence of Hennebert's sign, in which pressure changes in the external auditory canal evoke stereotyped eye movements that align in the plane of the dehiscent semicircular canal. This video case report demonstrates Hennebert's sign associated with SSCD syndrome and discusses its pathophysiological basis.

Electrocochleography as a diagnostic and intraoperative adjunct in superior semicircular canal dehiscence syndrome.

OBJECTIVE: To determine the electrocochleographic characteristics of ears with superior semicircular canal dehiscence (SSCD) and to examine its use for intraoperative monitoring in canal occlusion procedures. STUDY DESIGN: Case series. SETTING: Academic medical center. PATIENTS: Thirty-three patients (45 ears) had clinical and computed tomographic evidence of SSCD; 8 patients underwent intraoperative electrocochleography (ECoG) during superior canal occlusion; 9 patients underwent postoperative ECoG after SSCD occlusion. INTERVENTIONS: Diagnostic, intraoperative, and postoperative extratympanic ECoG; middle fossa or transmastoid occlusion of the superior semicircular canal. MAIN OUTCOME MEASURE: Summating potential (SP) to action potential (AP) ratio, as measured by ECoG, and alterations in SP/AP during canal exposure and occlusion. RESULTS: Using computed tomography as the standard, elevation of SP/AP on ECoG demonstrated 89% sensitivity and 70% specificity for SSCD. The mean SP/AP ratio among ears with SSCD was significantly higher than that among unaffected ears (0.62 versus 0.29, p < 0.0001). During occlusion procedures, SP/AP increased on exposure of the canal lumen (mean change ± standard deviation, 0.48 ± 0.30). After occlusion, SP/AP dropped below the intraoperative baseline in most cases (mean change, -0.23 ± 0.52). All patients experienced symptomatic improvement. All patients who underwent postoperative ECoG 1 to 3 months after SSCD repair maintained SP/AP of 0.4 or lesser. CONCLUSION: These findings expand the differential diagnosis of abnormal ECoG. In conjunction with clinical findings, ECoG may support a clinical diagnosis of SSCD. Intraoperative ECoG facilitates dehiscence documentation and allows the surgeon to confirm satisfactory canal occlusion.

Transcanal labyrinthectomy for intractable vertigo after unilateral cochlear implantation.

OBJECTIVE: Document the use of transcanal labyrinthectomy to treat disabling attacks of vertigo after unilateral cochlear implantation. PATIENT: A 46-year-old woman with severe-profound bilateral sensorineural hearing loss secondary to enlarged vestibular aqueducts underwent cochlear implantation for her right ear with a Nucleus Freedom device. The surgery was uneventful, and postoperative imaging confirmed that the electrode was positioned properly. She developed episodic vertigo 10 to 14 days after the implant surgery, which failed to improve with aggressive vestibular rehabilitation therapy. Plugging of the round window for possible perilymphatic fistula did not relieve her symptoms. INTERVENTION: Right transcanal labyrinthectomy supplemented by filling the vestibule with gentamicin-soaked Gelfoam and then a customized vestibular rehabilitation program. MAIN OUTCOME MEASURE: Comparison of vestibular symptoms and cochlear implant performance before and after transcanal labyrinthectomy. RESULTS: The patient had immediate relief of symptoms, and the function of the cochlear implant was not adversely affected. CONCLUSION: Transcanal labyrinthectomy may be an effective method to ablate the vestibular end organ after unilateral cochlear implantation. It can offer relief of disabling vertigo without adversely affecting the performance of the implant.

Persistent positional nystagmus: a case of superior semicircular canal benign paroxysmal positional vertigo?

Involvement of the superior semicircular canal (SSC) in benign paroxysmal positional vertigo (BPPV) is rare. SSC BPPV is distinguished from the more common posterior semicircular canal (PSC) variant by the pattern of nystagmus triggered by the Dix-Hallpike position: down-beating torsional nystagmus in SSC BPPV versus up-beating torsional nystagmus in PSC BPPV. SSC BPPV may be readily treated at the bedside, which is a key component in excluding central causes of down-beating nystagmus. We present an unusual video case report believed to represent refractory SSC BPPV based on the pattern of nystagmus and the absence of any other central signs.

Transmastoid labyrinthectomy for disabling vertigo in a patient with internal auditory canal pathology.

OBJECTIVE: Document the use of transmastoid labyrinthectomy to treat disabling vertigo secondary to a lesion in the internal auditory canal. PATIENT: A 69-year-old man with nonserviceable left hearing experienced disabling attacks of vertigo refractory to medical measures. Magnetic resonance imaging revealed a small left intracanalicular lesion with an irregular configuration and modest enhancement, suggesting either an unusual acoustic neuroma or a cavernoma. Tumor size remained stable on serial imaging, and the patient declined microsurgical resection, stereotactic radiation, or intratympanic gentamicin therapy. INTERVENTION: Transmastoid labyrinthectomy followed by a customized vestibular rehabilitation program. MAIN OUTCOME MEASURE: Comparison of patient symptoms preoperatively and at 5 and 8 months after surgery. RESULTS: Complete relief of vertigo was achieved, but the patient has moderate imbalance postoperatively. CONCLUSION: Transmastoid labyrinthectomy alone may be a viable treatment option in patients with an internal auditory canal neoplasm causing disabling attacks of vertigo.

Audiovestibular testing in patients with Meniere's disease.

In this article, the present state of the art with respect to audiovestibular testing for Meniere's disease (MD) is reviewed. There is no gold standard for MD diagnosis, and the classic dictum is that even the "best" tests yield positive results in only two-thirds of patients with MD. Still, we advocate the use and further investigation of advanced audiovestibular testing in patients with MD in an attempt to answer the questions that confront any clinician who cares for patients with audiovestibular symptoms.

Strategies to distinguish benign paroxysmal positional vertigo from rotational vertebrobasilar ischemia.

Vertigo provoked by head rotation is a classic symptom of rotational vertebrobasilar ischemia (RVBI). Inner ear disease can cause positional vertigo and mimic RVBI. We review the case of a patient with vertigo consistently triggered by leftward head rotation when supine. Computed tomography angiogram and dynamic arteriogram failed to show compression of the vertebral arteries with head rotation. Further evaluation revealed benign paroxysmal positional vertigo (BPPV) as the underlying etiology. Treatment of her BPPV led to complete resolution of her symptoms. A succinct overview of this common otologic disorder is provided, and strategies to help distinguish it from RVBI are discussed.

Can active lateral canal benign paroxysmal positional vertigo mimic a false-positive head thrust test?

We present a patient with positive head thrust test (HTT) and video-oculography (VOG) findings suggestive of active lateral semicircular canal (LSCC) benign paroxysmal positional vertigo (BPPV). This patient was seen in a tertiary vestibular clinic for episodic vertigo. He exhibited robust corrective refixation saccades on HTT to the right and evidence of active contralateral LSCC BPPV on positional testing. Treatment of the LSCC BPPV led to immediate resolution of vertigo and near-normalization of the HTT on follow-up testing. The pathophysiologic basis and clinical implications of LSCC BPPV mimicking a false-positive HTT are discussed in detail.

The incidence of coexistent autonomic and vestibular dysfunction in patients with postural dizziness.

PURPOSE: To evaluate the incidence of coexistent peripheral vestibular dysfunction and cardiovascular autonomic dysfunction in patients undergoing evaluation for dizziness exacerbated by postural changes. MATERIALS AND METHODS: Retrospective case review of 56 sequential patients seen from 2003 to 2006 at a tertiary center for a primary complaint of dizziness who underwent both passive tilt table testing for evaluation of neurocardiogenic etiology and quantitative vestibular testing. The vestibular test battery consisted of alternating bithermal caloric testing; computerized sinusoidal vertical axis rotation (at frequencies 0.01-0.64) with infrared videonystagmography; and oculomotor and positional testing including bilateral Dix-Hallpike, head center supine, and 30-degree supine head turns right and left. RESULTS: Eight of the 56 subjects had caloric weakness. Forty-five subjects (80%) had abnormal tilt table test findings. The incidence of coexistent neurocardiogenic and vestibular test abnormalities was 10.7%. There was no significant association between abnormal tilt table test result and caloric weakness (Fisher exact test; P = .64). The degree of compensation seen on vestibule-ocular reflex gain testing did not affect tilt table findings (chi2; P = .872). CONCLUSIONS: There is no difference in the rate of postural orthostatic intolerance in subjects with evidence of caloric weakness compared with those with normal caloric function.

Cervicogenic dizziness as a cause of vertigo while swimming: an unusual case report.

We present the unusual case of a competitive swimmer with cervicogenic dizziness manifesting as vertigo while she was surface swimming. This patient complained of brief and episodic room-spinning vertigo consistently associated with swimming the freestyle stroke and was referred to an otolaryngology clinic for evaluation. She did not have significant complaints of neck pain while swimming. Her history, examination findings, laboratory study results, differential diagnoses, and treatment are discussed in detail. A succinct overview of cervicogenic dizziness--a controversial diagnosis often overlooked by otolaryngologists-is also provided.