Structural connectivity changes in unilateral hearing loss.

Network connectivity, as mapped by the whole brain connectome, plays a crucial role in regulating auditory function. Auditory deprivation such as unilateral hearing loss might alter structural network connectivity; however, these potential alterations are poorly understood. Thirty-seven acoustic neuroma patients with unilateral hearing loss (19 left-sided and 18 right-sided) and 19 healthy controls underwent diffusion-weighted and T1-weighted imaging to assess edge strength, node strength, and global efficiency of the structural connectome. Edge strength was estimated by pair-wise normalized streamline density from tractography and connectomics. Node strength and global efficiency were calculated through graph theory analysis of the connectome. Pure-tone audiometry and word recognition scores were used to correlate the degree and duration of unilateral hearing loss with node strength and global efficiency. We demonstrate significantly stronger edge strength and node strength through the visual network, weaker edge strength and node strength in the somatomotor network, and stronger global efficiency in the unilateral hearing loss patients. No discernible correlations were observed between the degree and duration of unilateral hearing loss and the measures of node strength or global efficiency. These findings contribute to our understanding of the role of structural connectivity in hearing by facilitating visual network upregulation and somatomotor network downregulation after unilateral hearing loss.

Post headshake nystagmus: further correlation with other vestibular test results.

BACKGROUND: It is generally accepted that headshake nystagmus (HSN) is generated from an asymmetrical peripheral vestibular input and a correlation exists between HSN and canal paresis. There have been limited reports, however, how HSN correlates with the more recently introduced tests of vestibular function. AIMS/OBJECTIVES: To evaluate the correlation between HSN and unilateral weakness on caloric testing, high-frequency vestibulo-ocular reflex (VOR) function on video head impulse testing (VHIT) and otolith function determined by vestibular evoked myogenic potentials (VEMPs). METHODS: A retrospective study of all patients who underwent complete vestibular function testing at our tertiary referral center from 2016 to 2019 was performed. Demographic data, clinical diagnosis (where available), the results of video-nystagmography, vHIT, and VEMPs were evaluated. RESULTS: Of the 1499 patients in the study period, 101 (6.7%) had HSN. Vestibular test abnormalities were more common in patients with HSN. The sensitivity of HSN for underlying pathology was low in comparison with vestibular testing. However, HSN demonstrated a high specificity. CONCLUSIONS AND SIGNIFICANCE: HSN generation is likely more complex than caloric-induced nystagmus, probably due to additional variables within the vestibular system. HSN may provide clinicians with additional information concerning high-frequency VOR function involving lateral semicircular and otolith dysfunction.

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.

Prevalence of Cognitive and Vestibular Impairment in Seniors Experiencing Falls.

BACKGROUND: Falls are a growing concern in seniors (≥65 yrs). Cognitive impairment (CI) and vestibular impairment (VI) increase fall risk. The aim of this study is to assess the prevalence of CI and VI in seniors experiencing falls. METHODS: Participants (≥65 yrs) with falls were recruited from Falls Prevention Programs (FPPs) and a Memory Clinic (MC). CI was assessed using the Montreal Cognitive Assessment at FPPs. VI was assessed at an MC and FFPs using the Head Impulse- (video + bedside), Headshake-, Dix-Hallpike test, and test of sensory interaction in balance. Questionnaires included Dizziness Handicap Inventory (DHI) and Activities-specific Balance Confidence Scale (ABC). RESULTS: Of 41 participants (29 FPPs, 12 MC); mean age was 80.1 ± 7.1 years, and 58.5% were female. Overall, 82.9% had VI. At FPPs, 76.0% had CI, and 72.3% had CI + VI. Bilateral vestibular hypofunction (BVH) was more common than unilateral vestibular hypofunction (UVH) (70.6% vs. 29.4%); p = 0.016. Dizziness Handicap (DHI) was not different between those with a VI (23.5 ± 23.9) versus without VI [PVI + no impairment] (10.0 ± 15.4); p = 0.160. Balance confidence (ABC) was lowest in VI but not significantly different between those with a VI (63.4 ± 27.3) versus without VI [PVI + no impairment] (85.0 ± 16.5); p = 0.053. CONCLUSIONS: VI and CI are prevalent in seniors experiencing falls. For seniors with history of falls, both cognitive and vestibular functions should be considered in the assessment and subsequent treatment. Screening enables earlier detection, targeted interventions, and prevention, reducing the clinical and financial impact.

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.

Vestibular Exercises as a Fall Prevention Strategy in Patients with Cognitive Impairment.

Vestibular impairment (VI) and cognitive impairment (CI) are risk factors for senior falls. We tested the feasibility of a self-directed 12-week vestibular rehabilitation (VR) program in Memory Clinic patients (65 years+) with a fall, CI and VI. We assessed recruitment, exercise adherence and ability to complete questionnaires/assessments. Twelve patients with CI and falls were screened and 8/12 (75% - prevalence) had VI. All patients completed the screening tests/questionnaires (100% - completeness); 7/8 patients were recruited (87.5% - recruitment); 1/7 (85.7% - attrition) patient attended follow-up. VI is prevalent in patients with CI experiencing falls but traditional VR is not feasible, so a novel delivery of VR must be explored.

Les exercices de réadaptation vestibulaire comme stratégie de prévention des chutes chez des patients atteints de troubles cognitifs. Les troubles vestibulaires (TV) et les troubles cognitifs (TC) sont des facteurs de risque de chute chez les personnes âgées. À cet égard, nous avons évalué le caractère réalisable d'un programme autonome de réadaptation vestibulaire de 12 semaines offert, dans une clinique de la mémoire, à des patients âgés de 65 ans et plus ayant chuté au moins une fois et qui sont atteints de TV et de TC. Nous nous sommes ainsi penchés sur leur recrutement, leur adhésion aux exercices du programme et leur capacité à compléter des questionnaires d'évaluation. Douze patients aux prises avec des TC ont été examinés. De ce nombre, huit d'entre eux (75 %) étaient aussi atteints de TV. Tous ces patients ont complété des tests de dépistage ainsi que des questionnaires, lesquels ont été remplis dans 100 % des cas. Au total, sept patients sur huit ont été recrutés, soit 87,5 %, tandis qu'un seul, ce qui représente un taux d'attrition de 85,7 %, s'est présenté lors d'un suivi. Même si les TV affectent les patients atteints de TC, un programme de réadaptation vestibulaire n'est pas réellement réalisable dans ce contexte, de sorte qu'un nouveau programme devrait être exploré.

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.

Primary epidermoid cysts of the mastoid: clinical and treatment implications.

Epidermoid cysts of the temporal bone are extremely rare and such lesions arising in isolation within the mastoid bone have never been reported in literature. We report and describe the first two unique cases of primary epidermoid cysts arising in the mastoid bone. Of the two cases, one presented with progressive headache and imbalance and the other with unilateral hearing loss and tinnitus. Both cases needed CT and MRI scans and needed surgical management. We review the clinical presentations, histology, pathogenesis, radiological findings and management of these challenging cases. The diagnosis of an epidermoid cyst is based on clinical presentation, physical examination and especially the radiological, histological and intraoperative findings. Total removal of the lesion along with its capsule is recommended to prevent recurrence and to allow for a good long-term prognosis.

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.

Defying Deafness: Remembering Jack Ashley.

After he sustained a profound hearing loss in his only hearing ear following a routine myringoplasty, Jack Ashley became Britain's first deaf politician. His story is an inspiring one, converting a postoperative complication into a driver for success and change in the lives of millions of deaf and disabled people around the world.

Venous balloon test occlusion for pulsatile tinnitus assessment: A clinical feasibility study.

BACKGROUND: Pulsatile tinnitus (PT) can have huge impact on the patients' quality of life and can be associated with curable vascular anomalies. In the present study, we aim firstly to describe our protocol for venous BTO and secondly to report possible predictors for a positive BTO test. METHODS: All consecutive PT patients undergoing BTO for the purpose of determining eligibility for venous neuro-intervention were included. We recommend BTO for patients when there is uncertainty in the association of the venous pathology identified on non-invasive cross-sectional imaging (CTV or MRV) and the patient's symptoms. RESULTS: Between May 2016 and October 2022, we recorded 29 venous balloon test occlusions fulfilling our inclusions criteria. Over the 29 procedures scheduled, 8 finally did not lead to a successful balloon test occlusion. The main reason was that the patient did not hear the PT on the day the angiogram was performed. Two patients could not have the BTO due to difficulties in venous navigation. After BTO, only four patients of our cohort were scheduled for an endovascular treatment. CONCLUSION: We describe a technique and present a single cohort of venous BTO in severe PT patients with unclear anatomical cause. This angiographic test was useful to exclude patients from endovascular surgery and discuss the most probable cause of the PT. Complexity of vascular PT should support a patient-based approach when discussing interventional treatment.

Whole stimulated salivary flow: correlation with the pathology of inflammation and damage in minor salivary gland biopsy specimens from patients with primary Sjögren's syndrome but not patients with sicca.

OBJECTIVE: To determine which measure of the salivary flow rate, stimulated or unstimulated, is most strongly associated with pathologic changes in minor salivary gland (MSG) biopsy specimens, and to explore the correlation of salivary flow with oral surface damage, disease duration, and symptom severity in patients with primary Sjögren's syndrome (SS). METHODS: In all patients (n = 32), a biopsy of the MSG was performed, and stimulated salivary flow was assessed. Beginning in 2002, unstimulated salivary flow was also assessed. Scores for the severity of symptoms, according to the decayed/missing/filled teeth (DMF) index, were recorded. Associations between measures of salivary flow and covariates characterizing pathology were examined. RESULTS: A definite association between stimulated salivary flow and the MSG focus score, the grade of MSG fibrosis, the duration of dry mouth symptoms, and the DMF score was observed. In contrast, unstimulated salivary flow was not associated with fibrosis, atrophy, the DMF score, or the duration of dry mouth symptoms. In patients with primary SS, the DMF score was associated with pathologic changes in the MSG. Among patients with sicca, 57.9% had an abnormal unstimulated salivary flow rate (versus 82.4% of patients with primary SS), and 15.2% had an abnormal stimulated salivary flow rate (versus 61.8% of patients with primary SS). Among patients with sicca, neither stimulated salivary flow nor unstimulated salivary flow was associated with the degree of fibrosis or atrophy or with the DMF score. CONCLUSION: Compared with unstimulated salivary flow, stimulated salivary flow appeared to be a better measure of inflammation (according to the focus score) and fibrosis. In patients with sicca, the unstimulated salivary flow rate appeared to be abnormal more commonly compared with the stimulated salivary flow rate. In the future, stimulated salivary flow may serve as a noninvasive surrogate biomarker of inflammation and fibrosis as well as a measure of response to treatment in patients with primary SS.

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.

Genomic study of a large family with complex neurological phenotype including hearing loss, imbalance and action tremor.

Neurological disorders are often associated with a variety of symptoms, which can result from the combined action of genetic variants. We conducted a whole-genome analysis of a previously unreported unique multigenerational Dutch-Canadian family with a complex phenotype presenting with a combination of hearing loss, balance issues or action tremor. Ten family members were available for genetic study. The hearing loss and balance problems are explained by a pathogenic p.P51S substitution in COCH, which is a known founder mutation in Dutch and Belgium families affected by non-syndromic progressive sensorineural hearing loss often accompanied by vestibular dysfunction. Notably, p.P51S did not co-segregate with action tremor in our and reported kindreds. In our family, all 5 patients with tremor were carriers of the extremely rare p.R247W substitution in MCM9 (minor allele frequency in European population is 0.00003), which belongs to the top 0.1% of deleterious variants in the human genome. The MCM9 locus has not been previously associated with action tremor and deserves further investigation in future functional and genetic studies of action tremor.

Receiving Long-Term Disability or Pursuing a Legal Claim May Prevent Recovery From Chronic Dizziness.

OBJECTIVES/HYPOTHESIS: Chronic dizziness (CD) and imbalance have multiple etiologies. CD is strongly linked with psychiatric and psychological comorbidities, thus an interdisciplinary approach, including psychopharmacological interventions, is recommended. Despite the use of this comprehensive treatment approach, the recovery of individuals with CD that pursue long-term disability (LTD) insurance or legal claims (LC) appears hampered. As such, we aimed to compare symptom recovery from CD in an interdisciplinary setting between patients receiving LTD/LC versus those who were not, and to explore the factors that may contribute to changes in symptom severity. STUDY DESIGN: Retrospective cohort study. METHODS: Dizziness-related diagnoses were extracted from the charts of 195 adults in an outpatient interdisciplinary neurotology clinic in Toronto, Canada. Patients with baseline Dizziness Handicap Inventory (DHI) and Dizziness Catastrophizing Scale (DCS) assessments between August 2012 and July 2018 and a mean follow-up visit within approximately 10 months were included. The study participants were categorized as "LTD/LC+" (n = 92) or "LTD/LC-" (n = 103), referring to either receiving or pursuing LTD/LC or not, respectively. RESULTS: There were differences in the mean percentage changes in DHI (t[187] = 3.02, P = .003) and DCS (t[179] = 2.63, P = .009) scores between LTD/LC+ and LTD/LC- patients. LTD/LC+ patients showed 8.0% and 7.6% mean increases in DHI and DCS scores, respectively, whereas LTD/LC- patients showed 21.5% and 25.9% reductions in DHI and DCS scores, respectively, controlling for age, sex, and baseline illness severity. CONCLUSIONS: Patients receiving or pursuing LTD insurance or a legal claim did not improve from CD and dizziness catastrophizing compared to those who were not. Future studies are required to test these findings prospectively and to determine the factors that may contribute to symptom recovery, including the anxiety-aggravating effects of the LTD/LC process and the deleterious consequences of developing a sick-role while afflicted with a chronic illness. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:655-661, 2022.

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.

Post-traumatic peripheral vestibular disorders (excluding positional vertigo) in workers following head injury.

Benign paroxysmal positional vertigo has typically been reported to be the most common cause of post-traumatic dizziness. There is however paucity in the literature about other peripheral vestibular disorders post-head injury. This article provides an overview of other causes of non-positional dizziness post-head trauma from our large institutional experience. The UHN WSIB Neurotology database (n = 4291) between 1998 and 2018 was retrospectively studied for those head-injured workers presenting with non-positional peripheral vestibular disorders. All subjects had a detailed neurotological history and examination and vestibular testing including video nystagmography, video head impulse testing (or a magnetic scleral search coil study), vestibular-evoked myogenic potentials, and audiometry. Imaging studies included routine brain and high-resolution temporal bone CT scans and/or brain MRI. Based on a database of 4291 head-injured workers with dizziness, 244 were diagnosed with non-positional peripheral vertigo. Recurrent vestibulopathy (RV) was the most common cause of non-positional post-traumatic vertigo. The incidence of Meniere's disease in the post-traumatic setting did not appear greater than found in the general population. The clinical spectrum pertaining to recurrent vestibulopathy, Meniere's disease, delayed endolymphatic hydrops, drop attacks, superior semicircular canal dehiscence syndrome, and uncompensated peripheral vestibular loss are discussed.

Torrents of torment: turbulence as a mechanism of pulsatile tinnitus secondary to venous stenosis revealed by high-fidelity computational fluid dynamics.

BACKGROUND: Pulsatile tinnitus (PT) is a debilitating condition that can be caused by a vascular abnormality, such as an arterial or venous lesion. Although treatment of PT-related venous lesions has been shown to successfully cure patients of the associated 'tormenting' rhythmical sound, much controversy still exists regarding their role in the etiology of PT. METHODS: A patient presented with a history of worsening, unilateral PT. A partial venous sinus obstruction related to the large arachnoid granulation was detected on the right side, and subsequently stented at the right transverse sinus. High-fidelity computational fluid dynamics (CFD) was performed on a 3D model digitally segmented from the pre-stent venogram, with assumed pulsatile flow rates. A post-stent CFD model was also constructed from this. Data-driven sonification was performed on the CFD velocity data, blinded to the patient's self-reported sounds. RESULTS: The patient reported that the PT was completely resolved after stenting, and has had no recurrence of the symptoms after more than 2 years. CFD simulation revealed highly disturbed, turbulent-like flow at the sigmoid sinus close to auditory structures, producing a sonified audio signal that reproduced the subjective sonance of the patient's PT. No turbulence or sounds were evident at the stenosis, or anywhere in the post-stent model. CONCLUSIONS: For the first time, turbulence generated distal to a venous stenosis is shown to be a cause of PT. High-fidelity CFD may be useful for identifying patients with such 'torrents' of flow, to help guide treatment decision-making.