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In central as well as peripheral vestibular lesions, right-beating horizontal nystagmus is almost always associated with clockwise (top poles of the eyes beating to the right ear) torsional nystagmus when observed and vice versa (concordant nystagmus). This study aimed to determine the etiologies and mechanisms of horizontal and torsional nystagmus beating in the opposite directions (discordant nystagmus). We reviewed the medical records of 16 consecutive patients with discordant horizontal–torsional nystagmus who had been evaluated at the dizziness clinics of Seoul National University Bundang Hospital (n = 11, from March 2003 to March 2021) and Korea University Medical Center (n = 5, from March 2019 to March 2021). The underlying etiologies included inferior vestibular neuritis (n = 7), Meniere's disease (n = 4), internuclear ophthalmoplegia (n = 3), medullary hemorrhage (n = 1), and normal pressure hydrocephalus (n = 1). The torsional nystagmus decreased during the gaze in the same direction (for instance, during rightward gaze in clockwise nystagmus) and increased during the gaze in the opposite direction. Head-impulse tests (HITs) were positive for the ipsilesional posterior canal (PC) in all 11 patients with unilateral peripheral vestibulopathy and two of the three patients with unilateral central vestibulopathy. Discordant horizontal–torsional nystagmus may be observed in peripheral as well as central lesions. Given the findings of HITs and modulation of spontaneous nystagmus during lateral gazes, discordant horizontal–torsional nystagmus may be ascribed to selective damage of the excitatory or inhibitory pathway from the PC that innervates the ipsilateral superior oblique and contralateral inferior rectus muscles. [ABSTRACT FROM AUTHOR]

Fixation nystagmus refers to the nystagmus that appears or markedly increases with fixation. While relatively common in infantile (congenital) nystagmus, acquired fixation nystagmus is unusual and has been ascribed to lesions involving the cerebellar nuclei or the fibers projecting from the cerebellum to the brainstem. We aimed to report the clinical features of patients with acquired fixation nystagmus and discuss possible mechanisms using a model simulation and diagnostic significance. We describe four patients with acquired fixation nystagmus that appears or markedly increases with visual fixation. All patients had lesions involving the cerebellum or dorsal medulla. All patients showed direction-changing gaze-evoked nystagmus, impaired smooth pursuit, and decreased vestibular responses on head-impulse tests. The clinical implication of fixation nystagmus is that it may occur in central lesions that impair both smooth pursuit and the vestibulo-ocular reflex (VOR) but without creating a spontaneous nystagmus in the dark. We develop a mathematical model that hypothesizes that fixation nystagmus reflects a central tone imbalance due to abnormal function in cerebellar circuits that normally optimize the interaction between visual following (pursuit) and VOR during attempted fixation. Patients with fixation nystagmus have central lesions involving the cerebellar circuits that are involved in visual–vestibular interactions and normally eliminate biases that cause a spontaneous nystagmus. [ABSTRACT FROM AUTHOR]

Caloric tests are useful for disease surveillance of Meniere's disease (MD), although the interpretation of caloric tests remains controversial during the attacks of MD. Therefore, we aimed to characterize the findings of caloric tests during the attacks of MD. We analyzed the results of bithermal caloric tests during and between the attacks in 43 patients with unilateral definite MD. Evaluation was performed during the irritative/recovery phase in 22 and during the paretic phase in 26 patients. During the irritative/recovery phase, less than half of patients (10/22, 45%) showed a caloric asymmetry of more than 25%, lesser responses in the affected ear in six and in the healthy ear in the other four. In contrast, patients usually showed a caloric asymmetry of more than 25% during the paretic phase (19/26, 73%) with a decreased response almost always in the affected ear (18/19, 95%). Between the attacks, caloric asymmetry was found in less than half of the patients (20/43, 47%) with a decreased response almost always in the affected ear (19/20, 95%) when observed. The caloric asymmetry was less during the irritative/recovery phases than between the attacks (p = 0.007). In contrast, the caloric asymmetry was larger during the paretic phase than between the attacks (p = 0.041). The caloric asymmetry decreased during the irritative/recovery phases with an estimated mean difference of 34% (adjusted 95% CI 16–53%, p < 0.001) and 23% (adjusted 95% CI 8–38%, p = 0.002) compared to the paretic and interictal phases. Caloric responses fluctuate during and between the attacks of MD depending on the electrophysiologic status of the vestibular afferents. The results of caloric tests in MD, thus should be interpreted with consideration of each phase when the evaluation was done. [ABSTRACT FROM AUTHOR]

We aimed to characterize the central positional nystagmus (CPN) observed in lesions involving the inferior cerebellar peduncle (ICP). We analyzed the clinical and neurotologic findings in six patients with an isolated unilateral ICP infarction that had been diagnosed at a university hospital in South Korea from 2003 to 2019. Patients usually presented with acute vestibular syndrome in isolation (4/6, 67%). Ipsilesional spontaneous nystagmus was observed in five while supine (5/6, 83%). Four (4/6, 67%) patients showed CPN which included apogeotropic (n = 3) or geotropic (n = 1) during head turning to either side while supine, and vertical nystagmus during straight-head hanging, Dix-Hallpike maneuvers, or up-righting (n = 3). Four patients showed contraversive ocular tilt reaction or tilt of the subjective visual vertical. Bedside and video head-impulse tests were normal in all patients. CPN is a usual finding in ICP lesions, and may be ascribed to damage of the fibers running from the nodulus/uvula onto the vestibular nucleus via the ICP. [ABSTRACT FROM AUTHOR]

Given the characteristics of typewriter tinnitus, the paroxysmal nature with an excellent response to carbamazepine, the tinnitus may be ascribed to NVCC affecting the cochlear nerve [[2], [6]]. Dear Sirs, Vestibular paroxysmia (VP) is characterized by brief and recurrent vertigo that respond well to carbamazepine or oxcarbazepine [[1]]. Our patient presented with paroxysmal attacks of vertigo and typewriter tinnitus that resolved with carbamazepine. [Extracted from the article]

Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo worldwide. This review considers recent advances in the diagnosis and management of BPPV including the use of web-based technology and artificial intelligence as well as the evidence supporting the use of vitamin D supplements for patients with BPPV and subnormal serum vitamin D. [ABSTRACT FROM AUTHOR]

The bilateral lateral medullary lesions disrupt both the inhibitory Purkinje outflow to bilateral vestibular nuclei and the climbing fibers participating in the cerebellar VOR adaptation, resulting in phenotypically identical HIS compared to the global cerebellar lesions. During vertical HITs for left or bilateral anterior canal semicircular canals, the VOR gain was slightly increased and small corrective saccades were followed in the anti-compensatory direction (Fig. Normally, vertical eye movements derived from each vertical canal are offset but not when the anterior canal gain is increased due to the vestibulocerebellar lesions [[9]]. [Extracted from the article]

This study aimed to determine the etiologic distribution of dizziness and vertigo in a referral-based dizziness clinic in South Korea. We analyzed the diagnoses of 21,166 consecutive dizzy patients (12,691 women, mean age = 57.9 ± 15.7, age range = 3–97) seen from 2003 to 2019 using a registry and medical records. Overall, dizziness and vertigo were more common in women (60.0%, CI 0.59–0.61) than in men without a difference in age (57.7 ± 15.5 vs. 58.1 ± 16.1, p = 0.094). Benign paroxysmal positional vertigo (BPPV, 24.1%) was the most common cause of dizziness/vertigo, followed by psychiatric or persistent postural perceptual dizziness (20.8%), vascular disorders (12.9%), vestibular migraine (10.2%), Meniere's disease (7.2%), and vestibular neuritis (5.4%). These six disorders comprised more than 80% of all disorders. The etiology could not be determined in 5.0%, and more than one etiology was found in 14.1%. Vestibular migraine was the most common disorder in children and adolescents (< 19 years), psychiatric or persistent postural perceptual dizziness (26.3%) in the adults (19–64 years), and BPPV (28.2%) in the elderly (≥ 65 years). This etiologic distribution is similar to that reported in another country, and indicates no significant differences in the proportion of diseases causing dizziness and vertigo across different ethnic groups. This study provides valuable information to establish healthcare policy for dizziness and vertigo. [ABSTRACT FROM AUTHOR]

Bilateral vestibular dysfunction (BVD) refers to hypofunction of the vestibular nerves or labyrinths on both sides. Patients with BVD present with dizziness, oscillopsia, and unsteadiness, mostly during locomotion, which worsen in darkness or on uneven ground. Although aminoglycoside ototoxicity, Meniere's disease, infection, and genetic disorders frequently cause BVD, the etiology remains undetermined in up to 50% of the patients. The diagnosis of BVD requires both symptoms and documentation of deficient vestibulo-ocular reflex function using head-impulse, bithermal caloric, and rotatory chair tests. Since various neurologic and systemic disorders may present with BVD, clinicians should be cautious not to overlook the symptoms and signs of central nervous system and systemic involvements. Vestibular rehabilitation, application of vibrotactile and auditory feedbacks, and vestibular prosthesis can aid the patients with BVD along with the correction of the underlying causes. [ABSTRACT FROM AUTHOR]

This study aimed to define the clinical features and involved structures that aid in differentiation of neuromyelitis optica spectrum disorder (NMOSD) from multiple sclerosis (MS) involving the brainstem and cerebellum. We analyzed the clinical and ocular motor findings, and lesion distribution on brain MRIs in 42 patients with MS (17 men, mean age ± SD = 37 ± 12) and 26 with NMOSD (3 men, mean age ± SD = 43 ± 15) that were recruited from two university hospitals in South Korea (whole study population). An additional subgroup analysis was also conducted in 41 patients presenting acute brainstem or vestibular syndrome (brainstem syndrome population). Logistic regression analysis showed that bilaterality of the lesions (p = 0.012) and presence of horizontal gaze-evoked nystagmus (hGEN, p = 0.041) were more frequently associated with NMOSD than with MS in the whole study population. In the brainstem syndrome population, only hGEN (p = 0.017) was more frequent in NMOSD than in MS. The lesions specific for NMOSD were overlapped in the medial vestibular nucleus (MVN) and nucleus prepositus hypoglossi (NPH) at the pontomedullary junction. In conclusion, presence of hGEN and bilateral lesions involving the MVN and NPH favor the diagnosis of NMOSD rather than MS. [ABSTRACT FROM AUTHOR]

Diagnosis of combined peripheral and central vestibulopathy remains a challenge since the findings from peripheral vestibular involvements may overshadow those from central vestibular disorders or vice versa. The aim of this study was to enhance detection of these intriguing disorders by characterizing the clinical features and underlying etiologies. We had recruited 55 patients with combined peripheral and central vestibulopathy at the Dizziness Clinic of Seoul National University Bundang Hospital from 2003 to 2013. Peripheral vestibular involvement was determined by decreased caloric responses in either ear, and central vestibulopathy was diagnosed with obvious central vestibular signs or the lesions documented on MRIs to involve the central vestibular structures. Combined peripheral and central vestibulopathy could be classified into four types according to the patterns of vestibular presentation. Infarctions were the most common cause of acute unilateral cases while cerebellopontine angle tumors were mostly found in chronic unilateral ones. Wernicke encephalopathy and degenerative disorders were common in acute and chronic bilateral disorders. Twenty five (45.5%) patients showed only vestibular findings with or without auditory involvements, but association with gaze-evoked nystagmus, impaired smooth pursuit or central types of head shaking nystagmus indicated a central vestibular involvement in most of them (23/25, 92.0%). Given the requirements for urgent treatments and potentially grave prognosis of combined vestibulopathy, central signs should be sought even in patients with clinical or laboratory features of peripheral vestibulopathy. Scrutinized bedside evaluation, however, secured the diagnosis in almost all the patients with combined vestibulopathy. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 45-year-old woman presented with spontaneous vertigo for a day, who had suffered from cough and myalgia for a week before the presentation. Topics include features of acute unilateral peripheral vestibulopathy mimicking vestibular neuritis (VN) in the patient, signs of decreased ocular vestibular-evoked myogenic potentials (VEMPs), and diagnosis of anti-ganglioside antibody-associated acute unilateral peripheral vestibulopathy.

The article describes the case of a 63-year-old woman with diabetes mellitus and hypertension for two years who presented acute spontaneous vertigo and headache for ten days. Topics discussed include findings on the medical examination conducted on the patient, the bilaterally abnormal cervical vestibular-evoked myogenic potential (VEMPs) shown by the patient in the presence of normal ocular VEMPs, and dissociated VEMP results.

Internuclear ophthalmoplegia (INO) indicates a lesion involving the medial longitudinal fasciculus (MLF) that interconnects the abducens nucleus and medial rectus subnucleus of the oculomotor nuclear complex. In fact, rostral-caudal localization value of the INO is often limited except when it accompanies symptoms and signs owing to involvement of nearby structures. Ataxia is often observed in lesions involving the cerebellum or the fibers to and from it anywhere in the brainstem. Herein, we sought to determine the localizing value of INO plus ataxia in the rostrocaudal axis of the brainstem. Thirty patients with INO plus limb or truncal ataxia were subjected to analyses. For comparison, 20 patients with isolated INO without any ataxia served as the control. We determined the lesion extent in the MRIs responsible for INO plus ataxia using a probabilistic lesion mapping and subtraction analysis and analyzed the neuro-otologic findings using video-oculography. In patients with INO with limb or truncal ataxia, the responsible lesions were mostly restricted to the paramedian tegmentum at the pontomesencephalic junction. In contrast, the lesions causing isolated INO without ataxia were mostly located in the caudal or mid-pontine area. The rostro-caudal distribution of the lesions was similar among the patients with only limb ataxia ( n = 3), both limb and truncal ataxia ( n = 10), and only truncal ataxia ( n = 17). INO plus ataxia indicates a lesion involving the MLF at the pontomesencephalic junction. Damage to the brachium conjunctivum or mesencephalic locomotor region may explain the ataxia in association with INO in lesions involving this area. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 49-year-old man who was taken to the emergency room due to left ear tinnitus and vertigo. Medical diagnosis of the patient with the use of magnetic imaging resonance for the Meniere disease (MD) and response of the vestibular-evoked myogenic potentials (VEMPs) was performed. The article discusses the effect of the VEMPs leading to the labyrinthine ischemia in the patient.

A sound- and pressure-induced vestibuloocular reflex (VOR) has been described as vertical and torsional in superior canal dehiscence (SCD), and the rotational axes of induced VOR have been assumed to fit with the axis of the affected superior semicircular canal (SC). However, it has been difficult to characterize the pattern of vibration-induced VOR (ViVOR). We aimed to characterize the pattern of ViVOR by comparing the intensity and the axis of ViVOR with several clinical parameters of SCD. Ten symptomatic SCD patients were recruited. SCD size and location were measured on a reformatted image in the plane of the SC. Unilateral vibratory stimulation (100 Hz) was applied to the mastoid surface. ViVOR were recorded using 3D videooculography. The median 3D velocity of ViVOR was measured and the 3D vector trajectory plotted for reference against the axes of the human semicircular canals. A correlation between the magnitude of ViVOR and the size of SCD was evaluated. We also compared the location of SCD with the vertical-to-torsional component ratio of the ViVOR. ViVOR were present in 7 patients; 6 patients showed a substantial horizontal component in the excitatory direction in addition to strong torsional and weak vertical components. The computed rotational axes of ViVOR were located mostly between the axes of the ipsilateral SC and horizontal canal (HC) with a variable deviation to the axis of the ipsilateral posterior canal (PC). The magnitude of ViVOR was not related to the size of the SCD. The vertical-to-torsional component ratio of ViVOR tended to decline as the dehiscence was closer to the common crus. In SCD, mastoid vibration may stimulate the affected-side HC and PC as well as the SC. SCD can be suspected when excitatory horizontal torsional ViVOR direct to the side of the auditory symptoms. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Highlights: [•] Patients with isolated internuclear ophthalmoplegia (INO) frequently show abnormal ocular vestibular evoked myogenic potentials (VEMPs) in response to forehead tapping in the lesion side. [•] The medial longitudinal fasciculus (MLF) appears to contain the fibers for the otolith-ocular reflex from the contralateral ear. [•] The abnormal cervical VEMPs in some patients with isolated INO suggest a modulatory pathway for the inhibitory sacculocollic reflex descending in the MLF. [ABSTRACT FROM AUTHOR]

Even though trigeminovestibular connections are well established in animals, mastication-induced dizziness has been described only as a vascular steal phenomenon in humans. We determined induction or modulation of nystagmus in two index patients with mastication-induced vertigo, 12 normal controls, and 52 additional patients with peripheral ( n = 38, 26 with vestibular neuritis/labyrinthitis and 12 with Meniere's disease) or central ( n = 14, 11 with Wallenberg syndrome, two with cerebellar infarction, and one with pontine infarction) vestibulopathy during their acute or compensated phase. Both index patients developed mastication-induced vertigo after near complete resolution of the spontaneous vertigo from presumed acute unilateral peripheral vestibulopathy. The nystagmus and vertigo gradually built up during mastication and dissipated slowly after cessation of mastication. Brain MRI and cerebral angiography were normal in these patients. Mastication did not induce nystagmus in normal controls. However, mastication induced nystagmus in five (24 %) of the 21 patients without spontaneous nystagmus (SN) but with a previous history of a vestibular syndrome, and either increased (21/31, 68 %) or decreased (7/31, 23 %) the SN in almost all the patients (28/31, 90 %) with SN. Mastication may induce significant vertigo and nystagmus in patients with a prior history of acute vestibulopathy. The induction or modulation of nystagmus by mastication in both peripheral and central vestibulopathies supports trigeminal modulation of the vestibular system in human. The gradual build-up and dissipation suggest a role of the velocity storage mechanism in the generation of mastication-induced vertigo and nystagmus. [ABSTRACT FROM AUTHOR]

Cerebral infarction presenting with isolated vertigo remains a diagnostic challenge. To define the clinical characteristics of unilateral infarctions restricted to the vestibular nuclei, two patients with isolated unilateral vestibular nuclear infarction had bedside and laboratory evaluation of the ocular motor and vestibular function, including video-oculography, bithermal caloric irrigation, the head impulse test (HIT) using magnetic scleral coils, and cervical and ocular vestibular-evoked myogenic potentials (VEMPs). We also reviewed the literature on isolated vertigo from lesions restricted to the vestibular nuclei, and analyzed the clinical features of seven additional patients. Both patients showed spontaneous torsional-horizontal nystagmus that beat away from the lesion side, and direction-changing gaze-evoked nystagmus. Recording of HIT using a magnetic search coil system documented decreased gains of the vestibular-ocular reflex for the horizontal and posterior semicircular canals on both sides, but more for the ipsilesional canals. Bithermal caloric tests showed ipsilesional canal paresis in both patients. Cervical and ocular VEMPs showed decreased or absent responses during stimulation of the ipsilesional ear. Initial MRIs including diffusion-weighted images were normal or equivocal, but follow-up imaging disclosed a circumscribed acute infarction in the area of the vestibular nuclei. Infarctions restricted to the vestibular nuclei may present with isolated vertigo with features of both peripheral and central vestibulopathies. Central signs should be sought even in patients with spontaneous horizontal-torsional nystagmus and positive HIT. In patients with combined peripheral and central vestibulopathy, a vestibular nuclear lesion should be considered especially when hearing is preserved. [ABSTRACT FROM AUTHOR]

Abstract: A 74-year-old woman with sudden vertigo and dysarthria showed spontaneous nystagmus beating rightward, upward and clockwise. She also exhibited dysfunction of the left utricle and superior and horizontal canals, which was documented by head impulse and heave tests, measurements of ocular torsion and subjective visual vertical tilt, bithermal caloric tests, and rotation axis analysis of the spontaneous nystagmus. In contrast, functions of the left posterior canal, saccule, and cochlea were remained intact, as evidenced by normal head impulse test, audiometry and vestibular evoked myogenic potential. MRI revealed an acute infarction in the left lateral pons of anterior inferior cerebellar artery (AICA) territory. Our patient with AICA infarction showed isolated damage to the superior vestibular labyrinth or its afferents with preservation of the inferior vestibular labyrinth and auditory function. Our patient provides further evidence that isolated damage to the superior vestibular labyrinth or its afferents may be a mechanism of isolated vascular vertigo. [Copyright &y& Elsevier]

Background and Objectives: Vestibular syncope is a condition in which vertigo‐induced hemodynamic changes cause syncope. This study investigated the clinical and laboratory findings of vestibular syncope and tried to refine our knowledge of the mechanism underlying this newly recognized entity. Methods: This study retrospectively analyzed 53 patients (33 women, median age = 63 years [interquartile range = 54–71 years]) with vestibular syncope from January 2017 to December 2021. To explain the mechanism of vestibular syncope, we incorporated a velocity‐storage model into the dual reflex pathways comprising the vestibulo‐sympathetic reflex and baroreflex and predicted the cardiovascular responses. Results: Twenty (37.7%) patients had multiple episodes of vestibular syncope, and seven (13.2%) had potentially life‐threatening injuries. Meniere's disease (20.8%) and benign paroxysmal positional vertigo (9.4%) were the most common underlying vestibular disorders. Abnormal vestibular function tests included impaired cervical vestibular‐evoked myogenic potentials (57.5%) and positive head impulse tests (31.0%). Orthostatic hypotension was found in 19.5% of patients. Dyslipidemia (30.2%) and hypertension (28.3%) were common medical comorbidities. The dual reflex pathways incorporating the function of the velocity‐storage circuit in the brainstem and cerebellum suggest that vestibular syncope is a neurally mediated reflex syncope associated with a sudden hemodynamic change during vertigo. This change can be arterial hypertension triggered by a false downward inertial cue, as suggested previously, or hypotension driven by a false upward inertial cue. Conclusions: Vestibular syncope is associated with various vestibular disorders and requires careful evaluation and intervention to prevent recurrent falls and significant injuries. [ABSTRACT FROM AUTHOR]

Paroxysmal positional nystagmus frequently occurs in lesions involving the cerebellum, and has been ascribed to disinhibition and enhanced canal signals during positioning due to cerebellar dysfunction. This study aims to elucidate the mechanism of central positional nystagmus (CPN) by determining the effects of baclofen on the intensity of paroxysmal positional downbeat nystagmus due to central lesions. Fifteen patients with paroxysmal downbeat CPN were subjected to manual straight head-hanging before administration of baclofen, while taking baclofen 30 mg per day for at least one week, and two weeks after discontinuation of baclofen. The maximum slow phase velocity (SPV) and time constant (TC) of the induced paroxysmal downbeat CPN were analyzed. The positional vertigo was evaluated using an 11-point numerical rating scale (0 to 10) in 9 patients. After treatment with baclofen, the median of the maximum SPV of paroxysmal downbeat CPN decreased from 30.1°/s [interquartile range (IQR) = 19.6—39.0°/s] to 15.2°/s (IQR = 11.2—22.0°/s, Wilcoxon signed rank test, p < 0.001) with the median decrement ratio at 40.2% (IQR = 28.2—50.6%). After discontinuation of baclofen, the maximum SPV re-increased to 24.6°/s (IQR = 13.1—34.4°/s, Wilcoxon signed rank test, p = 0.001) with the median increment ratio at 23.5% (IQR = 5.2—87.9%). In contrast, the TCs of paroxysmal downbeat CPN remained unchanged at approximately 3.0 s throughout the evaluation. The positional vertigo also decreased with the medication (Wilcoxon signed rank test, p = 0.020), and remained unchanged even after discontinuation of medication (Wilcoxon signed rank test, p = 0.737). The results of this study support the prior presumption that paroxysmal CPN is caused by enhanced responses of the semicircular canals during positioning due to cerebellar disinhibition. Baclofen may be tried in symptomatic patients with paroxysmal CPN. [ABSTRACT FROM AUTHOR]

Evolution of vestibular function requires further elucidation in spinocerebellar ataxia (SCA). This study aimed to determine temporal evolution in the findings of head impulse tests (HITs) in SCA type 6 (SCA6). We serially evaluated HITs in 12 patients with SCA6 using video-oculography for 3 months to 5 years [median = 12 months, interquartile range (IQR) = 9–50] at two university hospitals in South Korea. Patients (8/12, 67%) usually showed abnormal responses at least for one semicircular canal during video-HITs. The gains of the vestibulo-ocular reflex (VOR) for the anterior canals (ACs) were larger than those for the posterior canals (PCs, p = 0.005) at initial presentation. During the follow-up, the VOR gains decreased for the horizontal canals (HCs, p = 0.008) and ACs (p = 0.021), but those for the PCs remained unchanged (p = 0.212). Perverted HITs were observed in seven patients (7/12, 58%). The differences in the head impulse VOR gains were larger between the ACs and PCs (ΔACs − PCs) in those with perverted HITs than in those without (p = 0.003). The gains for each semicircular canal showed a negative correlation with the Scale for the Assessment and Rating of Ataxia (HCs, Spearman's coefficient = − 0.675, p = 0.003; ACs, − 0.637, p = 0.006; PCs, − 0.605, p = 0.010). The head impulse gain of the VOR may serve a marker for clinical decline in SCA6. The dissociation in the temporal evolution of the VOR gain indicates dissimilar cerebellar modulation of the vestibular signals from each semicircular canal. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to define the factors affecting accuracy of bedside determination of the involved side in HC-BPPV. Interventions: We developed 44 video clips including the nystagmus induced during supine head-roll test from patients with apogeotropic (n = 23) or geotropic (n = 21) HC-BPPV. The intensity of nystagmus was also quantified using video-oculography. Each video clip was presented twice to 25 participants, 14 medical students, and 11 medical personnel trained in neurology or neurotology, and the participants reported the lesion side using an evaluation sheet after each presentation. From the quantified video-oculographic data, absolute difference and asymmetry (absolute difference divided by the sum) of nystagmus intensity were calculated. Main outcomes and measures: The accuracy of bedside lateralization of HC-BPPV was 83.5% after the first presentation, and 86.0% after the second presentation, and was not different between the medical students and trained personnel after the second presentation. The accuracy was more closely correlated with the asymmetry than the absolute difference (Spearman's ρ = 0.627, p < 0.001). With a cut-off for the asymmetry at 30.8%, the accuracy was estimated at 93.8% with a sensitivity of 92.9%, and the area under the ROC curve of 0.779. Conclusions and relevance: The accuracy of bedside lateralization of the affected side is acceptable in HC-BPPV when the nystagmus asymmetry is more than 30%. [ABSTRACT FROM AUTHOR]

Cerebellar nodulus and uvula and their connections with the vestibular nuclei form the so‐called velocity‐storage circuit. Lesions involving the velocity‐storage circuit give rise to positional vertigo and nystagmus. Herein, we present a 32‐year‐old man with cerebellar nodulus and uvular hemorrhage who showed periodic vertigo and downbeat nystagmus in the supine position. To explain this unusual pattern, we adopted velocity‐storage model with a lesion on the neural connection between the gravity and inertia estimators, resulting in periodic neural impulses and a gravity bias in a specific position. This report expands the spectrum of central positional nystagmus due to dysfunction of the velocity‐storage mechanism. [ABSTRACT FROM AUTHOR]

Background and purpose: The temporal characteristics of stroke risks were evaluated in emergency department patients who had a diagnosis of peripheral vertigo. It was also attempted to reveal the stroke risk factor amongst those with peripheral vertigo. Methods: This is a parallel‐group cohort study in a tertiary referral hospital. After assigning each of 4367 matched patients to the comparative set of peripheral vertigo and appendicitis‐ureterolithiasis groups and each of 4911 matched patients to the comparative set of peripheral vertigo and ischaemic stroke groups, the relative stroke risk was evaluated. In addition, to predict the individual stroke risk in patients with peripheral vertigo, any association between the demographic factors and stroke events was evaluated in the peripheral vertigo group. Results: The peripheral vertigo group had a higher stroke risk than the appendicitis‐ureterolithiasis group (hazard ratio 1.73, 95% confidence interval 1.18–2.55) but a lower risk than the ischaemic stroke group (hazard ratio 0.30, 95% confidence interval 0.24–0.37). The stroke risk of the peripheral vertigo group was just below that of small vessel stroke. The stroke risk of the peripheral vertigo group differed markedly by time: higher within 7 days, moderate between 7 days and 1 year, and diminished thereafter. Old age (>65 years), male gender and diabetes mellitus were the risk factors for stroke in the peripheral vertigo group. Conclusion: Patients with a diagnosis of peripheral vertigo in the emergency department showed a moderate future stroke risk and so a stroke preventive strategy tailored to the timing of symptom onset and individual risk is required. [ABSTRACT FROM AUTHOR]

The incidence and characteristics of acute vestibular symptoms, responsible structures, and lateralization of the causative lesions in supratentorial stroke remain unknown. This study aimed to determine the incidence, clinical features, and anatomical correlation of acute vestibular symptoms in supratentorial stroke. We performed a prospective, multicenter, observational study that had recruited patients with supratentorial stroke from the neurology clinics of referral-based four university hospitals in Korea. All patients received a constructed neuro-otological evaluations, and neuroimaging. We analyzed the incidence of acute vestibular symptoms, abnormal ocular motor and vestibular function tests, and stroke lesions. Of 1301 patients with supratentorial stroke, 48 (3.7%) presented with acute vestibular symptoms, and 13 of them (1%) had the vestibular symptoms in isolation. In patients with acute vestibular symptoms, abnormal findings included spontaneous nystagmus (5%), impaired horizontal smooth pursuit (41%), and abnormal tilt of the subjective visual vertical (SVV) (20%). Video head impulse and caloric tests were normal in all the patients. There was no clear correlation between acute vestibular symptoms and involvement of specific vestibular cortex. In patients with unilateral stroke, there was also no lateralization of the causative lesions of acute vestibular symptoms (left vs. right; 52 vs. 48%), even in patients with vertigo (left vs. right; 58 vs. 42%). This study demonstrates that the incidence of acute vestibular symptoms in supratentorial stroke is 3.7%, with being isolated in 1%. The widespread lesions responsible for acute vestibular symptoms implicate diffuse multisensory cortical–subcortical networks in the cerebral hemispheres without a lateralization. [ABSTRACT FROM AUTHOR]

Differentiation of spinocerebellar ataxia type 17 (SCA17) from Huntington's disease (HD) is often challenging since they share the clinical features of chorea, parkinsonism, and dystonia. The ocular motor findings remain to be elucidated in SCA17, and may help differentiating SCA17 from HD. We retrospectively compared the ocular motor findings of 11 patients with SCA17 with those of 10 patients with HD. In SCA17, abnormal ocular motor findings included impaired smooth pursuit (9/11, 82%), dysmetric saccades (9/11, 82%), central positional nystagmus (CPN, 7/11, 64%), abnormal head-impulse tests (4/11, 36%), and horizontal gaze-evoked nystagmus (GEN, 3/11, 27%). Among these, CPN was more frequently observed in SCA17 than in HD (7/11 (64%) vs. 0/10 (0%), p = 0.004) while saccadic slowing was more frequently observed in HD than in SCA17 (8/10 (80%) vs. 2/11 (18%), p = 0.009). Of six patients with follow-up evaluation, five later developed bilateral saccadic hypermetria (n = 4), GEN (n = 1), CPN (n = 1), bilaterally abnormal smooth pursuit (n = 1), and hyperactive head-impulse responses (n = 1) along with a clinical decline. Ocular motor abnormalities can be utilized as a diagnostic marker for differentiation of SCA17 from HD as well as a surrogate marker for clinical decline in SCA17. [ABSTRACT FROM AUTHOR]

We sought to determine the cerebellar structures responsible for tilt suppression of post-rotatory nystagmus. We investigated ocular motor findings and MRI lesions in 73 patients with isolated cerebellar lesions who underwent recording of the vestibulo-ocular reflex (VOR) using rotatory chair tests. Tilt suppression of post-rotatory nystagmus was diminished in 27 patients (27/73, 37.0 %). The gains of the VOR and the TCs of per- and post-rotatory nystagmus did not differ between the patients with diminished and with normal tilt suppression. The patients with impaired tilt suppression showed perverted ('cross-coupled') head-shaking nystagmus (pHSN) and central positional nystagmus (CPN) more frequently than those with normal responses. Tilt suppression was impaired in five (71.4 %) of the seven patients with isolated nodulus and uvular infarction. Probabilistic lesion-mapping analysis showed that the nodulus and uvula are responsible for tilt suppression. Impaired tilt suppression may be ascribed to disruption of cerebellar contribution to the vestibular velocity-storage mechanism, which integrates information from the semicircular canals and otolith organs to help derive the brain's estimate of the head orientation relative to the pull of gravity. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 47-year-old man who was referred for further evaluation of progressive visual loss in both eyes for 3 months. It mentions that video-oculography documented intermittent windmill nystagmus with a counter-clockwise rotation of the beating direction. It informs that genetic analysis for Leber’s hereditary optic neuropathy was negative for mitochondrial DNAs. It states that Windmill nystagmus resembles periodic alternating nystagmus (PAN).

In spinocerebellar ataxia type 6 (SCA6), the vestibular dysfunction and its correlation with other clinical parameters require further exploration. We determined vestibular responses over a broad range of stimulus acceleration in 11 patients with SCA6 (six men, age range=33-72 years, mean age±SD=59±12 years) using bithermal caloric irrigations, rotary chair, and head impulse tests. Correlations were also pursued among disability scores, as measured using the International Cooperative Ataxia Rating Scale, disease duration, age at onset, cytosine-adenine-guanine (CAG) repeat length, and the gain of the vestibulo-ocular reflex (VOR). In response to relatively low-acceleration, low-frequency rotational and bithermal caloric stimuli, the VOR gains were normal or increased regardless of the severity of disease. On the other hand, with relatively high-acceleration, high-frequency head impulses, there was a relative increase in gain in the mildly affected patients and a decrease in gain in the more severely affected patients and gains were negatively correlated with the severity of disease (Spearman correlation, R=−0.927, p<0.001). Selective decrease of the vestibular responses during high-acceleration, high-frequency stimuli may be ascribed to degeneration of either the flocculus or vestibular nuclei. The performance of the VOR during high-acceleration, high-frequency head impulses may be a quantitative indicator of clinical decline in SCA6. [ABSTRACT FROM AUTHOR]

Isolated vestibular syndrome may occur all along the vestibular pathways from the peripheral labyrinth to the brain. By virtue of recent developments in clinical neurotology and neuroimaging, however, diagnosis of isolated central vestibulopathy is increasing. Here, we review five distinct syndromes of isolated central vestibular syndrome from lesions restricted to the vestibular nuclei, the nucleus prepositus hypoglossi, the flocculus, the tonsil, and the nodulus, and introduce a new vestibular syndrome from isolated involvement of the inferior cerebellar peduncle. Decreased responses to head impulses do not exclude a central lesion as a cause of isolated vestibular syndrome. Brain imaging, including diffusion-weighted magnetic resonance imaging (MRI), may be falsely negative during the acute phase in patients with isolated vestibular syndrome because of a stroke. Central signs should be sought carefully in patients with isolated vertigo, even when the patients show the features of peripheral vestibulopathy and negative MRIs. Recognition of these isolated central vestibular syndromes would aid in defining the lesions responsible for various vestibular manifestations in central vestibulopathy. [ABSTRACT FROM AUTHOR]

Highlights: [•] Rats well tolerate global cerebral ischemia up to 20min during 4-vessel occlusion. [•] Among the vestibular structures, the medial vestibular nucleus (MVN) is most vulnerable to ischemia in rats. [•] The frequent occurrence of isolated vascular vertigo in human is supported by the selective ischemic vulnerability of MVN confirmed in this experiment. [•] The 4-vessel occlusion adopted in the study may be easily utilized to induce posterior circulation ischemia in rats. [ABSTRACT FROM AUTHOR]

Background: Vestibular symptoms/signs frequently coexist with migraine, but the mechanisms of migraine-relatedvestibular dysfunction remain to be elucidated. This study aimed to determine altered brain metabolism in vestibularmigraine. Methods: Two patients with vestibular migraine underwent 18F-fluorodeoxy glucose (FDG) positron-emission tomography(PET) during and between attacks of vestibular migraine in addition to detailed neurotological evaluation. Weanalyzed the regional brain metabolism of the patients in comparison with that of age-matched healthy controls in eachpatient. We also compared ictal with interictal FDG PET using a subtraction method.Results: During the attacks, both patients showed an activation of the bilateral cerebellum and frontal cortices, anddeactivation of the bilateral posterior parietal and occipitotemporal areas. One patient also showed hypermetabolism inthe dorsal pons and midbrain, right posterior insula, and right temporal cortex while the other patient had an additionalactivation of the left temporal cortex. Compared with interictal images, ictal PET showed increased metabolism in thebilateral cerebellum, frontal cortices, temporal cortex, posterior insula, and thalami.Conclusion: During the attacks of vestibular migraine, the increased metabolism in the temporo-parieto-insular areas andbilateral thalami indicates activation of the vestibulo-thalamo-cortical pathway, and decreased metabolism in the occipitalcortex may represent reciprocal inhibition between the visual and vestibular systems. [ABSTRACT FROM AUTHOR]

Rotational vertebral artery syndrome (RVAS) is characterized by recurrent attacks of paroxysmal vertigo, nystagmus, and ataxia induced by head rotation. We report on a patient who developed atypical RVAS due to compression of the vertebral artery (VA) terminating in the posterior inferior cerebellar artery (PICA). A 59-year-old man suffered from vertigo and nystagmus induced by leftward head rotation and oculography showed right beating horizontal-torsional and downbeat nystagmus. Cerebral angiography showed hypoplastic right VA terminating in PICA without connection to the basilar artery. The basilar artery received its flow from the left VA only and branched out both anterior inferior cerebellar arteries. Cerebral angiography revealed a complete occlusion of the right distal VA at the level of the C1-2 junction when the head was rotated to a leftward position. In contrast, the blood flow through the left vertebral and basilar arteries remained intact while turning the head to either side. The hemodynamic compromise observed in our patient with RVAS indicates that isolated vertigo and nystagmus may occur due to transient ischemia of the inferior cerebellum or lateral medulla. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 59-year-old woman who had suffered from recurrent vertigo for 2 months and later found out to have cerebellopontine angle (CPA) meningioma that mimicked vestibular paroxysmia. The meningioma originating from the CPA has showed recurrent paroxysmal spontaneous vertigo that mimicked vestibular paroxysmia. The patient was placed on carbamazepine per day and discharged 4 days later.

A letter to the editor is presented which discusses the case of a patient with vertigo and downbeat nystagmus (DBM) induced by swallowing.

This study aimed to determine the prevalence and mechanism of linear vertigo reported by the patients during the attacks of benign paroxysmal positional vertigo (BPPV). We prospectively evaluated the characteristics (rotational vs. linear) of positional vertigo in 70 patients with posterior and horizontal canal BPPV using a questionnaire allowing multiple choices. In patients with linear vertigo, we further assessed the directionality of linear vertigo. We adopted the velocity-storage model to explain the occurrence and direction of linear vertigo in these patients with BPPV. Patients reported only rotational vertigo in 46 (46/70, 65.7%), only linear vertigo in 10 (14.3%), and both rotational and linear vertigo in 14 (20%). The patients experienced fear from rotational vertigo in 54 (54/70, 77.1%) and from linear vertigo in 20 (20/70, 28.6%). The direction of linear vertigo was concordant with the direction of inertial acceleration predicted by the velocity-storage model. Patients with BPPV may experience linear as well as rotational vertigo during the attacks. This linear vertigo may be ascribed to centrally estimated inertial acceleration. [ABSTRACT FROM AUTHOR]

Highlights • Amplitude of cervical vestibular-evoked myogenic potentials (cVEMP) representing saccule-related neural function decreases with ageing. • Decreased estimated glomerular filtration rate (eGFR) is associated with reduced cVEMP amplitudes. • The deleterious effect of free T4 on cVEMP amplitude occurs in younger subjects but not in older ones. Abstract Objective This study attempted to identify systemic factors for age-related decline in neural function originating from the saccule using cervical vestibular-evoked myogenic potentials (cVEMP) parameters. Methods We recruited 129 symptomatic vertiginous patients who did not have known disorder affecting the cVEMP pathway (mean age = 52.4 ± 13.9). The indicators of saccule-related neural function were the sum of normalized cVEMP amplitude (SNA) and the average of p13 latency on both sides (average latency, AL). Any associations between cVEMP and systemic factors were evaluated using a linear regression. Result SNA decreased with ageing (p < 0.001) in univariable regression. The estimated glomerular filtration rate (eGFR) was positively associated with SNA (p = 0.002). Hematocrit, C-reactive protein, vitamin D, and free thyroxine (T4) showed a trend of association with SNA (p < 0.2). SNA was associated with ageing, increased free T4, and decreased eGFR in multivariable analysis. In the subgroup analysis, SNA was significantly associated with free T4 in younger patients (mean age = 41.5 ± 9.91) but not in the older ones (mean age = 63.5 ± 6.54). AL did not show any significant associations with systemic factors. Conclusion Decreased eGFR and increased free T4 as well as aging may be risk factors for decline of saccule-related neural function. Significance Neural function originating from the saccule may be affected by systemic factors. [ABSTRACT FROM AUTHOR]

Objective Perverted downbeat head-shaking nystagmus (pdHSN) has been considered a sign of central pathology. Two hypotheses have been advanced as the mechanisms of pdHSN without proper validation. This study aimed to elucidate the mechanism of pdHSN. Methods Eighteen patients with pdHSN due to central lesions were subjected to analyses of their oculographic characteristics. The peak velocity, temporal features including the duration and time constant (TC), rotational axis of pdHSN were analyzed. To determine the most relevant mechanism of pdHSN, we compared the TCs of pdHSN with those of downbeat nystagmus after vertical head-shaking in four subjects, and with the TCs of horizontal head-shaking nystagmus (HSN) in three subjects who had both horizontal and downbeat nystagmus after head-shaking. Results The duration of pdHSN ranged from 14 to 25 s and the estimated TC was from 3.9 to 7.8 s. When the data were pooled after the intensities of the nystagmus in each patient were normalized, the TC was 5.2 (95% CI = 5.0–5.4) seconds from nonlinear regression test. The rotational vectors of pdHSN ( n = 8) were mostly aligned between the anterior semicircular canals. The estimated TC of downbeat nystagmus after vertical head-shaking (5.8 s) was similar to that of pdHSN (6.0 s) in four subjects tested. In contrast, the TC of horizontal HSN (10.9 s) was significantly larger than that of pdHSN (4.9 s) in three subjects. Conclusions The characteristics of TCs of HSN in our patients with central lesions suggest that pdHSN is due to enhanced activities of the central anterior canal pathway. Significance pdHSN is a sign indicative of central pathology causing cerebellar dysfunction, especially when it associated with other neuro-otological signs. [ABSTRACT FROM AUTHOR]

Diagnosis of central vestibulopathy remains a challenge when it is associated with peripheral vestibular dysfunction because neurotological findings from peripheral vestibulopathy may overshadow those from central vestibular involvements. To define the characteristics of disorders involving both peripheral and central vestibular structures, we classified the combined vestibulopathies into four types according to their vestibular manifestations, and describe a typical case in each subtype. Infarction involving the territory of anterior inferior cerebellar artery is the most common cause of acute unilateral cases, whereas tumors involving the cerebellopontine angle should be of prime suspicion in patients with chronic unilateral ones. Wernicke encephalopathy was most common in patients with acute bilateral combined vestibulopathy while degenerative disorders should be considered in chronic bilateral ones. Since the head impulse test (HIT) is mostly positive in combined vestibulopathy, signs of central vestibular dysfunction other than negative HIT should be sought carefully even in patients with obvious clinical or laboratory features of peripheral vestibulopathy. [ABSTRACT FROM AUTHOR]