Central Vestibular Dysfunction in Head Injury.

OBJECTIVES: This study aims to provide an overview of dizziness post head injury in those with prominent features for central vestibular dysfunction (CVD) in comparison to those with a post-traumatic peripheral vestibular etiology. STUDY DESIGN: Retrospective. SETTING: University Health Network (UHN) Workplace Safety and Insurance Board (WSIB) database from 1988 to 2018 were evaluated for post-traumatic dizziness. METHODS: The UHN WSIB neurotology database (n = 4291) between 1998 and 2018 was retrospectively studied for head-injured workers presenting with features for CVD associated with trauma. All patients had a detailed neurotological history and examination, audiovestibular testing that included video nystagmography (VNG) and cervical vestibular-evoked myogenic potentials (cVEMPs). Imaging studies including routine brain and high-resolution temporal bone computed tomography (CT) scans and/or intracranial magnetic resonance imaging (MRI) were available for the majority of injured workers. RESULTS: Among 4291 head-injured workers with dizziness, 23 were diagnosed with features/findings denoting CVD. Complaints of imbalance were significantly more common in those with CVD compared to vertigo and headache in those with peripheral vestibular dysfunction. Atypical positional nystagmus, oculomotor abnormalities and facial paralysis were more common in those with CVD. CONCLUSION: Symptomatic post-traumatic central vestibular injury is uncommon. It occurred primarily following high-impact trauma and was reflective for a more severe head injury where shearing effects on the brain often resulted in diffuse axonal injury. Complaints of persistent imbalance and ataxia were more common than complaints of vertigo. Eye movement abnormalities were highly indicative for central nervous system injury even in those with minimal change on CT/MRI.

Effectiveness of vestibular rehabilitation therapy in patients with idiopathic Cerebellar Ataxia with Bilateral Vestibulopathy (iCABV).

OBJECTIVE: To evaluate the benefit of vestibular rehabilitation therapy (VRT) in the management of patients with idiopathic cerebellar ataxia with bilateral vestibulopathy (iCABV). BACKGROUND: iCABV is a hindbrain degenerative disorder with impairment of both central and peripheral vestibular pathways. There is combined failure of four compensatory eye movement systems including the vestibulo-ocular reflex (VOR), optokinetic reflex, smooth pursuit and the visually enhanced vestibulo-ocular reflex (VVOR). Phenotypic presentation includes postural and gait instability, oscillopsia and dizziness with active head movement. The benefit of VRT in iCABV patients has not been established. METHODS: A retrospective review was performed on a cohort of twelve patients diagnosed with iCABV in a multidisciplinary neuro-otology clinic. All participated in VRT and completed their suggested course of VRT. The following clinical measures were assessed before starting and after finishing VRT: 1) Dizziness Handicap Inventory (DHI), 2) Activities-Specific Balance Confidence (ABC) Scale, 3) Catastrophization scale, 4) Positive Affective Negative Affective Score (PANAS), 5) Dynamic Gait Index (DGI) and 6) Modified Clinical Test of Sensory Interaction in Balance (mCTSIB). The number of falls historically was recorded in addition to gait speed (ft./sec). RESULTS: Following VRT, patients were found to have improved balance on mCTSIB (condition 4 : 7 vs 18 seconds, P = 0.04) and a better postural stability with a reduced number of falls (p = 0.01). No statistically significant improvement was seen in the DHI, ABC, Catastrophization scale, DGI, PANAS and gait speed (p > 0.05). CONCLUSIONS: iCABV patients who underwent VRT were found to have a better postural stability and reduced risk of falls. VRT was not found to significantly improve patients' overall subjective perception of their symptoms or their psychological status.

Contralesional High-Acceleration Vestibulo-Ocular Reflex Function in Vestibular Schwannoma.

Impairment of ipsilesional vestibulo-ocular reflex (VOR) function is well described in vestibular schwannoma (VS) and a correlation between gain of the VOR and tumor size has been suggested. Bilateral VOR impairment may also occur in VS patients, but its mechanisms are poorly understood. We sought to explore the effect of unilateral VS on ipsilesional and contralesional high-acceleration VOR function using video head impulse testing, and evaluate potential factors responsible for contralesional VOR impairment. MATERIALS AND METHODS: Chart review in tertiary referral center of patients with unilateral VS, who completed neurotological examination and vestibular function testing. RESULTS: One hundred one patients (mean age 57.4 yrs) were included. Maximal tumor diameter ranged from 0.3 to 5.0 cm. Forty one patients had evidence of brainstem compression from VS on magnetic resonance imaging (MRI). Ipsilesional and contralesional VOR impairment was present in 81 (80%) and 44 (43%) patients, respectively. Bilateral VOR impairment was seen in 42 (42%) patients. Bilateral VOR impairment correlated with tumor size. Presence of brainstem compression was associated with reduced ipsilesional VOR gain, but not contralesional VOR gain.

The Relationship Between Disorders of Bone Metabolism and Benign Paroxysmal Positional Vertigo: A Systematic Review.

OBJECTIVES: Several studies have reported an association between benign paroxysmal positional vertigo (BPPV) and bone mineral density or serum vitamin D levels. The aim of this review is to provide further clarification regarding the relationship between BPPV and calcium metabolism. DESIGN: PubMed and MEDLINE databases were systematically reviewed to identify all English language papers regarding the relationship between BPPV and the following terms: osteoporosis, osteopenia, bone mineral density, serum vitamin D levels, and bone metabolism. RESULTS: Of the 456 identified records, 28 studies were eligible for this review. Most were retrospective studies with inherent limitations and often conflicting results. While the literature is not conclusive, osteoporosis in patients of at least 50 years old appears to have an association with BPPV. Similarly, an association was observed between recurrent BPPV and vitamin D deficiency. CONCLUSION: There is only weak evidence to support the relationship between BPPV and osteoporosis or low serum 25-hydroxyvitamin D levels. Further prospective studies with more robust methodologies are needed to clarify the association between BPPV and disorders of bone metabolism.

Elevated ocular VEMP responses in the absence of a superior semicircular canal dehiscence.

BACKGROUND: Vestibular evoked myogenic potentials (VEMPs) have an accepted role in the diagnosis of the superior semicircular canal dehiscence (SSCD) syndrome. The current impression is that ocular VEMPs (oVEMPs) are more sensitive than cervical VEMPs (cVEMPs) for detecting a SSCD and that oVEMP testing in response to air conducted sound provides an excellent screening test without risk of radiation exposure from computerized tomography (CT). AIMS/OBJECTIVES: To report on patients with elevated oVEMP amplitudes but without evidence for a SSCD on multiplanar CT imaging. MATERIAL AND METHODS: Retrospective chart review of all patients referred for vestibular function testing to our department. Patients with oVEMP peak-to-peak amplitudes ≥17 µν without evidence for a SSCD on imaging were evaluated. RESULTS: 26 patients had oVEMP peak-to-peak amplitudes ≥17 µν with no evidence of a SSCD on imaging. The most common diagnosis was Meniere's disease in those identified. CONCLUSION AND SIGNIFICANCE: oVEMPs can provide false positive results for diagnosis of a SSCD and an elevated oVEMP amplitude in itself is insufficient for diagnosis of a SSCD.

Long-Term Outcomes from Blind Sac Closure of the External Auditory Canal: Our Institutional Experience in Different Pathologies.

OBJECTIVES: This study reports long-term results of blind sac closure of the external auditory canal performed for various pathologies, compares the complication rates and the need for revision surgery. MATERIALS AND METHODS: This study is a retrospective review. Ninety-six cases of blind sac closure performed for various pathologies were included in this study. The primary pathologies included extensive mucosal disease in an open mastoid cavity, cholesteatoma, skull base lesion, cerebrospinal fluid leak, and osteoradionecrosis of the temporal bone. Preoperative history, postoperative complications, and the need for revision surgery were evaluated. RESULTS: The most common indication for blind sac closure in our series involved skull base lesions (62.5%). The mean follow-up period was 46 months (4 months - 20 years). The total complication rate related to blind sac closure was 10.4%. The median time between surgery and long-term complications was 5.5 years. Patients with chronic mucosal disease had the highest rate of complications. CONCLUSION: Blind sac closure of external meatus can be effectively performed for different pathologies. Long-term follow-up with patients is necessary. Patients with chronic mucosal disease have the highest complication rates.

Management of invasive intralabyrinthine cholesteatoma: Can one realistically preserve hearing when disease is medial to the otic capsule?

PURPOSE: To report our long-term results in surgical management of invasive intralabyrinthine cholesteatoma. MATERIAL AND METHODS: The study is a case series in a tertiary referral center. Retrospective chart review of all mastoid operations performed for chronic ear disease between 1994 and 2019 at University Health Network, Toronto. The type of surgery, intraoperative findings, hearing outcome, recurrence of disease and the need for revision surgery were evaluated. RESULTS: 10 cases of extensive petrous bone cholesteatoma medial to the otic capsule were identified in 616 mastoid surgeries. All but one patient with extensive petrous bone cholesteatoma who underwent an exteriorizing procedure to preserve cochlear function failed the first surgery. A second procedure was needed in all cases due to complications which included facial palsy, recurrent cholesteatoma or internal auditory canal (IAC) abscess. Hearing was not preserved in any patient. In contrast, 57 ears with cholesteatomatous labyrinthine fistula lateral to the otic capsule had matrix exteriorized and had very good long-term results. CONCLUSION: We were rarely able to preserve hearing in massive petrous bone cholesteatoma. There should be no hesitation to remove the otic capsule to exteriorize diseases even under circumstances where residual cochlear and vestibular function is present if required to provide a safe ear.

Neurotological findings after electrical injury at the workplace.

OBJECTIVES/HYPOTHESIS: Neurotological findings secondary to electrical injuries have rarely been reported in the world literature. We attempt to characterize the neurotological findings following electrical injury and to determine the role head injury and loss of consciousness play in this population's clinical presentation. STUDY DESIGN: Retrospective cohort study. METHODS: A database containing 3,438 patients with work-related injuries was scanned for individuals who sustained and survived electrical injuries at work. Detailed analysis of the frequencies of presenting features and test results was performed. A comparative analysis was made between the subsets of patients with and without loss of consciousness and/or head injury. RESULTS: A cohort of 42 patients was identified. All patients had multiple symptoms. Dizziness was a significant complaint in all workers with electrical injuries. Other common complaints included tinnitus and imbalance. Characterization of these symptoms is provided in detail according to statistical frequency. In this cohort, 25 workers had a concomitant head injury and 17 workers had an associated loss of consciousness. There was no statistically significant difference when clinical presentation, examination, and balance testing results were compared between the subsets. CONCLUSIONS: Frequency and characterization of symptoms following electrical injury are provided. Dizziness is the most common presenting neurotological feature. Loss of consciousness and/or associated head injury do not affect the clinical presentation in this particular population. LEVEL OF EVIDENCE: 2b. Laryngoscope, 127:2126-2131, 2017.