The value of vestibular graviceptive pathway evaluation in the diagnosis of unilateral peripheral vestibular dysfunction.

BACKGROUND: Evaluation of vestibular graviceptive pathway (VGP) in patients with unilateral peripheral vestibular dysfunction (UPVD) has received increasing attention from researchers. The study aimed to investigate the value of VGP evaluation in the diagnosis of UPVD. METHODS: Ninety-five UPVD patients were divided into attack and remission phase groups. VGP evaluation-related indicators, including subjective visual vertical (SVV), subjective visual horizontal (SVH), head tilt, ocular torsion (OT), and skew deviation (SD), were measured, and their correlations with cochleovestibular function test results were analyzed. The possible etiologies of contralesional VGP (c-VGP) were analyzed. RESULTS: Positive rates of SVV, SVH, OT, and SD were significantly higher, and the degrees of SVV, SVH, and OT were significantly greater in the attack phase group than the remission phase group. The sides with abnormal VGP evaluation results were correlated with the sides with hearing loss, abnormal caloric, and video head impulse test (vHIT) results. A total of 14 patients showed c-VGP, and possible etiologies included contralateral benign paroxysmal positional vertigo (n = 4), bilateral hearing loss (n = 8), bilateral vHIT gain reduction (n = 1), autoimmune diseases (n = 6), vascular risk factors (n = 6), lacunar infarction (n = 3), and endolymphatic hydrops (n = 3). CONCLUSIONS: Alterations in SVV, SVH, OT, and SD were noted in UPVD patients in different phases, which are presumed to be related to dynamic vestibular compensation; correlations between VGP evaluation results and cochleovestibular function test results indicate that VGP evaluation may be helpful for the diagnosis of the side affected in UPVD; the presence of c-VGP may be related to bilateral labyrinth lesions or endolymphatic hydrops on the affected side; and the involvement of autoimmune mechanisms also deserves attention.

The diagnostic value of the ocular tilt reaction plus head tilt subjective visual vertical (±45°) in patients with acute central vascular vertigo.

Objectives: To investigate the localization diagnostic value of the ocular tilt reaction (OTR) plus head tilt subjective visual vertical (SVV) in patients with acute central vascular vertigo (ACVV). Methods: We enrolled 40 patients with acute infarction, 20 with unilateral brainstem infarction (BI) and 20 with unilateral cerebellar infarction (CI). We also included 20 patients with unilateral peripheral vestibular disorders (UPVD) as the control group. The participants completed the OTR and SVV during head tilt (±45°) within 1 week of symptom onset. Results: In patients with ACVV, including that caused by lateral medullary infarction (100%, 2/2), partial pontine infarction (21%, 3/14), and cerebellum infarction (35%, 7/20), we observed ipsiversive OTR, similar to that seen in UPVD patients (80.0%, 16/20). Some of the patients with medial medullary infarction (50%, 1/2), partial pons infarction (42%, 6/14), midbrain infarction (100%, 2/2), and partial cerebellum infarction (30.0%, 6/20) showed contraversive OTR. The skew deviation (SD) of the BI group with ACVV was significantly greater than that of the UPVD group (6.60 ± 2.70° vs. 1.80 ± 1.30°, Z = -2.50, P = 0.012), such that the mean SD of the patients with a pons infarction was 9.50° and that of patients with medulla infarction was 5.00°. In ACVV patients with no cerebellar damage, the area under the curve of the receiver operating characteristic curve corresponding to the use of SD to predict brainstem damage was 0.92 (95%CI: 0.73-1.00), with a sensitivity of 100% and a specificity of 80% when SD ≥ 3°. We found no statistical difference in SD between the UPVD and CI groups (1.33 ± 0.58° vs. 1.80 ± 1.30°, Z = -0.344, P = 0.73). Compared with the UPVD patients, the ACVV patients with a partial pons infarction (43%, 6/14, χ2 = 13.68, P = 0.002) or medulla infarction (25%, 1/4, χ2 = 4.94, P = 0.103) exhibited signs of the ipsiversive E-effect with the contraversive A-effect, while those with a partial medulla infarction (50%, 2/4), pons infarction (43%, 6/14), or cerebellar infarction (60%, 12/20) exhibited a pathological symmetrical increase in the E-effect. Conclusions: The evaluation of OTR plus head tilt SVV (±45°) in vertigo patients is helpful for identifying and diagnosing ACVV, especially when SD is ≥ 3° or the E-effect is symmetrically increased.

Diagnosing and localizing the acute vestibular syndrome - Beyond the HINTS exam.

When assessing the acutely dizzy patient, the HINTS 'Plus' (Head Impulse, Nystagmus, Test of Skew, 'Plus' a bedside assessment of auditory function) exam is a crucial component of the bedside exam. However, there are additional ocular motor findings that can help the clinician distinguish peripheral from central etiologies and enable accurate localization, especially when the patient has acute dizziness, vertigo and/or imbalance but without spontaneous nystagmus. We will review the literature on these findings which are 'beyond HINTS' and include saccades/ocular lateropulsion, smooth pursuit, and provocative maneuvers including head-shaking and positional testing (not part of the HINTS exam). Additionally, we will expound on the localizing value of nystagmus, ocular alignment and the ocular tilt reaction (parts of the HINTS exam). The paper has been organized neuroanatomically, based on brainstem and cerebellar structures that have been reported to cause the acute vestibular syndrome.

Update on the medial longitudinal fasciculus syndrome.

The medial longitudinal fasciculus is a key structure for conjugate horizontal eye movements by relaying signals from the abducens internuclear neurons to the medial rectus subdivision of the contralateral oculomotor nucleus. Thus, lesions involving the medial longitudinal fasciculus give rise to a typical neuro-ophthalmological sign, the internuclear ophthalmoplegia, which is characterized by impaired adduction of the ipsilesional eye and dissociated abducting nystagmus of the contralateral eye during attempted contralesional horizontal gaze. In addition, medial longitudinal fasciculus lesions may produce various other ocular motor abnormalities since the medial longitudinal fasciculus also conveys the signals for the control of the vestibulo-ocular reflex and smooth pursuit. Other possible ocular motor abnormalities include spontaneous vertical-torsional nystagmus, contraversive ocular tilt reaction, and impaired vestibulo-ocular reflex, especially for the contralesional posterior canal. Recognition of the ocular motor findings observed in the medial longitudinal fasciculus syndrome would aid in detection and localization of potentially grave lesions involving the brainstem.

Skew Deviation.

Ocular skew deviation is an acute vertical misalignment resulting from the disruption of vestibular input to the interstitial nucleus of Cajal, involving the utriculo-ocular pathway, the cerebellum or the thalamus. A large percentage of skew cases associated with globe torsion and head tilt have complex or sinister etiologies, necessitating its differentiation from more common causes of acute onset vertical deviation in a sensitive and cost-efficient manner.This paper briefly reviews the anatomy and vestibular function of the inner ear, outlines the utriculo-ocular pathway, and discusses the things you need to know about skew to aid in clinical oculo-motor practice in 2022.

Resolution of Diplopia and Torsion Following Yttrium Aluminum Garnet (YAG) Laser Capsulotomy in a Patient With the Ocular Tilt Reaction.

The ocular tilt reaction is a rare neuro-ophthalmological phenomenon commonly occurring due to an injury to the vestibulo-ocular pathway, or a thalamic, brainstem, or cerebellar lesion. Most ocular tilt reactions are transient and demonstrate spontaneous recovery. This report documents the immediate resolution of diplopia and the patient's ocular tilt reaction following visual recovery from left yttrium aluminum garnet laser capsulotomy.

Different time course of compensation of subjective visual vertical and ocular torsion after acute unilateral vestibular lesion.

PURPOSE: Time course of the recovery of otolithic dis-function caused by superior vestibular neuritis has been examined in fifteen patients. METHODS: The subjective visual vertical (SVV) and the ocular cyclotorsion (OT) have been measured four times after the acute episode up to 1 year RESULTS: In most of the patients the SVV tilt returned to control values within few months (3-6 months) after the acute episode, while OT remained out of normal range in almost all patients a year later. CONCLUSION: The abnormal OT observed after 1 year from the acute episode of vestibular neuritis, suggests that the otolithic receptors remained altered for several months and the OT may be a good indicator of the entity of the residual peripheral otolithic lesion. Moreover, the dissociation between the SVV tilt recovery and that of OT supports the issue that the two signs of the otolithic disfunction are only partially linked each other with centrally or peripherally distinct re-balancing circuits.

Analysis of the Skew Deviation to Evaluate the Period of Onset of a Canalolithiasis After Macular Damage.

Benign paroxysmal positional vertigo (BPPV) is the most common peripheral vestibular end-organ disease, and it is one of the first causes of access to the emergency room. The moment of migration of the otoconial debris in a semicircular canal does not necessarily coincide with the moment of detachment of the debris themselves. Consequently, the paroxysmal positional vertigo could arise with a variable delay with respect to the mechanical damage suffered by the macula. The aim of this work is to try to identify objective criteria to establish whether a canalolithiasis is synchronous or diachronic to the damage. The analysis of skew deviation in the context of ocular tilt reaction in patients with canalolithiasis could provide useful information to understand if macular damage occurred at the origin of the disease and when the damage may have occurred. In this study, 38 patients with BPPV were analyzed based on the type of skew deviation that was presented. We found that if the eye on the side of the canalolithiasis is hypotropic the damage of the utriculus is likely recent (last 10 days), if it is hypertropic the damage is not recent (20 days before) and finally if the eyes are at the same height it could be an utricular damage in compensation (occurring the last 10-20 days) or a secondary labyrinth canalolithiasis, without associated utricular damage. Our results show that the evaluation of skew deviation in patients suffering from BPPV could be useful to evaluate: (a) if a positional paroxysmal nystagmus can be related to an previous relevant injury event (for example a head injury that occurred days before the crisis); (b) if it is a BPPV of recent onset or a re-entry of the debris into the canal.

Approaching Acute Vertigo With Diplopia: A Rare Skew Deviation in Vestibular Neuritis.

Evaluating the patient with acute constant vertigo or diplopia can be a daunting task for clinicians, who recognize that such symptoms can be the manifestation of potentially devastating disorders like stroke but may be uncomfortable eliciting and interpreting the key symptoms and subtle signs that distinguish dangerous from benign causes. We present a novel and highly instructive case of a patient with acute vertigo and binocular diplopia from a large skew deviation due to vestibular neuritis. As the case unfolds, text and video commentary guide the clinician through the important elements of the history, bedside examination, and laboratory evaluation necessary for accurate diagnosis in the acute vestibular syndrome. We demonstrate how to interpret nystagmus and properly perform the head impulse test and test of skew deviation and discuss the pitfalls of overreliance on imaging when evaluating patients with acute vertigo.

[Analysis of features of ocular tilt reaction for patients with vestibular neuritis].

Objective:To analyze the clinical characteristics of ocular tilt reaction in vestibular neuritis patients and discuss its value to the diagnosis of vestibular neuritis.Method:Thirty-five patients with vestibular neuritis confirmed between January 2016 and March 2018 underwent bedside vestibular function physical examination including nystagmus, head impulse test(HIT),head shaking nystagmus(HSN), ocular tilt reaction(OTR), Romberg sign, Fukuda stepping. All patients underwent head CT scan and brain MRI scan + DWI to exclude bleeding and infarction. Pure tone audiometry and acoustic impedance check to understand the hearing and middle ear pressure.Result:In all the 35 patients with vestibular neuritis, OTR was observed in 29 patients (82.8%); Typical OTR was seen in 5 of 35 patients (14.3%), atypical OTR was seen in 24 of 35 patients (68.5%), static ocular torsion were observed in 4 of 35 patients (11.4%). Ipsiversive skew deviation and head tilt were observed in 20 of 35 patients (57.1%). In 29 cases, the symptoms of patients with OTR disappeared after 1-4 days, with an average of (2.62 ± 0.26) days.Conclusion:As an important index for diagnosis of vestibular neuritis, OTR is often neglected by clinicians, and its positive rate is high, which can be used as a key inspection items of bedside vestibular function physical examination.

Ipsiversive Ocular Torsion, Skew Deviation, and Hearing Loss as Initial Signs of Anterior Inferior Cerebellar Artery Infarction.

A 67-year-old man with hypertension and type 2 diabetes mellitus was admitted to our hospital because of left hearing loss and vertical diplopia. A neurological examination showed ocular torsion, skew deviation, and sensorineural hearing loss in the left ear. Brainstem and cerebellar neurological signs were not observed. Left middle cerebellar peduncle infarction was evident on magnetic resonance imaging. He was treated with antiplatelet, however, the infarct progressed after this administration. Ocular tilt reaction (OTR) involves the triad of ocular torsion, skew deviation, and head tilt. Ipsiversive OTR components associated with hearing loss can be early diagnostic signs of anterior inferior cerebellar artery infarction.

Skew Deviation and Partial Ocular Tilt Reaction Due to Intratympanic Gentamicin Injection, with Review of the Literature.

Skew deviation is a rare side effect of intratympanic gentamicin injection for intractable Meniere's disease. When the skew deviation is accompanied by pathologic head tilt and ocular torsion, the result is an ocular tilt reaction (OTR). The authors report the case of a 56-year-old man with refractory Meniere's disease who developed binocular vertical diplopia following intratympanic gentamicin injection and was found to have skew deviation and a partial ocular tilt reaction. The authors also review the reported cases of skew deviation following intratympanic gentamicin and confirm this phenomenon, which has only rarely been reported in the literature.

Uphill/downhill nystagmus.

Differential diagnosis between peripheral and central spontaneous nystagmus can be difficult to classify (as peripheral or central) even on the basis of criteria recommended in the recent literature. The aim of this paper is to use the combination of spontaneous nystagmus and ocular tilt reaction to determine the site of origin of the disease that causes nystagmus. We propose to classify the nystagmus in: 1) "Uphill" nystagmus in which the nystagmus takes on an inclined plane and the direction of the fast phase is towards the hypertropic eye (this type of nystagmus is likely peripheral); 2) "Downhill" nystagmus when the nystagmus beats toward the hypotropic eye (this type of nystagmus is likely central); 3) "Flat" nystagmus when the plane on which nystagmus beats is perfectly horizontal: in this case, we cannot say anything about the site of lesion (it was only detected in 15% of cases). The spatial position of nystagmus vector has to be considered as an intrinsic characteristic of the nystagmus itself (as direction, frequency, angular velocity etc.) and must be reported in the description, possibly giving an indication of the site of damage (peripheral or central). In particular, similar results are obtained by comparing the inclination of the nystagmus with the head impulse test (HIT, considered the best bedside test now available). It seems that this sign may confirm HIT for safer diagnosis or replace it in case of doubt. In contrast, in case of "Flat" nystagmus (probably attributable to the fact that the utricular maculae are spared), HIT can replace observation of the plane of the nystagmus. Thus, the two signs confirm and integrate each other. The test does not require additional time and is not tedious for the patient. It is proposed that it be included in the evaluation of spontaneous nystagmus in everyday clinical practice.

Skew Deviation: Case Report and Review of the Literature.

OBJECTIVE: To present a patient with a sudden onset ocular tilt reaction (OTR) and review recent knowledge and evolving insights of the underlying pathophysiological mechanisms of skew deviation and OTR. METHODS: A middle-aged hypertensive man who had previously suffered stroke with good recovery presented with sudden-onset double vision, slurred speech, ataxia, and a head tilt. Romberg test was positive. The patient denied having disturbances of visual acuity, eye pain, or recent trauma. The right eyeball was pushed upward. The patient complained of double vision in any gaze direction. Movements of the extraocular muscles (EOMs) in the horizontal plane were normal, whereas vertical version and convergence were not possible. We administered a Hess-Lancaster test, cover test, fundoscopic examination, Parks-Bielschowsky three-step test, upright-supine test, brain magnetic resonance imaging (MRI), transcranial doppler (TCD) ultrasonography, electrocardiogram (ECG), Holter monitor (24 h), and echocardiography. RESULTS: The Hess-Lancaster test showed superior rectus muscle and inferior obliquus muscle palsy to the left and rectus inferior muscle and superior obliquus muscle palsy to the right. The right eyeball fell behind when looking downward and the left eyeball when looking upward. Cover alternating test was positive from vertical, R/L. Examination of the ocular fundus showed incyclotorsion of elevated right eye and excyclotorsion of depressed eye. The Parks-Bielschowsky three-step test was negative. A brain MRI with gadolinium revealed a small zone of diffusion restriction in the medial portion of the right cerebral peduncle and right thalamus. There was a gradual improvement in the patient's neurological status following treatment. CONCLUSION: Skew deviation, a not uncommon clinical condition, should be promptly recognized when binocular vertical diplopia cannot be interpreted by trochlearis and oculomotor nerve lesion, myasthenia gravis, or orbital pathology. Maddox rod, cover test, Parks-Bielschowsky three-step, and other tests should help to establish the diagnosis. The prognosis depends on etiology, but it is commonly favorable; the majority of patients recover spontaneously after less than a year. More invasive management options should be discussed thereafter.

Altered processing of otolithic information in isolated lateral medullary infarction.

Ocular and cervical vestibular-evoked myogenic potentials (VEMPs) evaluate the function of otolithic pathways in central as well as peripheral vestibular disorders. This study aimed to determine the associations and dissociations of otolithic dysfunction in lateral medullary infarction (LMI), the most well-known disorder of central vestibulopathy. At the Dizziness Clinic of a referral-based University Hospital, 45 patients with isolated LMI (28 men, mean age = 55.6 ± 12.5) had evaluation of the ocular tilt reaction (OTR), tilt of the subjective visual vertical (SVV), and ocular and cervical VEMPs from Janurary 2011 to August 2015 during the acute phase, 1-11 days from the symptom onset (median = 2 days). Almost all (42/45, 93 %) patients showed at least one component of the OTR or SVV tilt that was invariably ipsiversive. In contrast, oVEMPs were abnormal only in 12 (27 %) and cVEMPs in 13 (29 %) patients. Only three patients showed abnormal results in all the tests of the OTR, SVV tilt, and ocular and cervical VEMPs. Abnormal oVEMPs were more common in patients with the OTR than those without (38 vs 6 %, Pearson X 2 test, p = 0.021). In contrast, abnormality of cVEMPs showed no correlation with the presence of OTR (28 vs 31 %, Pearson X 2 test, p = 0.795). In patients with LMI, ipsiversive OTR is invariable, but abnormalities of oVEMPs and cVEMPs were much less common and mostly dissociated even in the patients with abnormal results. This discrepancy in otolithic dysfunction suggests different anatomical substrates and/or dissimilar reciprocal modulation for processing of each otolithic signal in central vestibular structures located in the dorsolateral medulla.

Inferior cerebellar peduncular lesion causes a distinct vestibular syndrome.

BACKGROUND AND PURPOSE: The inferior cerebellar peduncle (ICP) contains various fibres to and from the cerebellum relating to the integration of the proprioceptive and vestibular functions. However, the full clinical features of isolated unilateral ICP lesions have not been defined in humans. METHODS: Eight consecutive patients with isolated unilateral ICP lesions at the pontine level (six with stroke, one with multiple sclerosis and one with brainstem encephalitis) received bedside neurological and neuro-otological evaluations and underwent laboratory tests including measurements of the subjective visual vertical (SVV) and ocular torsion, bithermal caloric tests and pure tone audiometry. RESULTS: All patients developed isolated acute vestibular syndrome (AVS) with ipsilesional spontaneous nystagmus (n = 7) and contralesional ocular tilt reaction (OTR) and/or SVV tilt (n = 7). In view of the normal head impulse test in all patients and skew deviation in one, our patients met the criteria for AVS from central lesions. Five patients showed a directional dissociation between the OTR/SVV tilt and body lateropulsion that fell to the lesion side whilst the OTR/SVVtilt was contraversive. CONCLUSIONS: A unilateral ICP lesion at the pontine level leads to the development of isolated AVS. However, a negative head impulse test and directional dissociation between OTR/SVV tilt and body lateropulsion may distinguish lesions involving unilateral ICP at the pontine level from those affecting other vestibular structures.

Skew deviation e ocular tilt reaction versus paralisia do nervo troclear / Skew deviation and ocular tilt reaction versus trochlear nerve palsy

Skew deviation é o desalinhamento vertical dos olhos causado por disfunção unilateral no tronco cerebral, cerebelo ou sistema vestibular periférico, comprometendo as vias por onde transitam impulsos dos órgãos otolíticos aos núcleos oculomotores. Está frequentemente associado a torção ocular e inclinação da cabeça, compondo, assim, a ocular tilt reaction. Neste artigo os autores ressaltam aspectos históricos, fisiológicos, etiopatogênicos e clínicos que contribuem para caracterizar ambas as condições, além da diferenciação clínica com a paralisia do nervo troclear.

Skew deviation is the vertical misalignment of the eyes caused by unilateral dysfunction in the brain stem, cerebellum or peripheral vestibular system, resulting imbalance in otolith input to the oculo-motor system. It's often associated with ocular torsion and head tilt, which together comprise the ocular tilt reaction. In this article the authors emphasize the historical, physiological, etiopathogenesis and clinical aspects that contribute to characterize both conditions, and help to differentiate them clinically from trochlear nerve palsy.

Ocular vestibular evoked myogenic potentials to head tap and cervical vestibular evoked myogenic potentials to air-conducted sounds in isolated internuclear ophthalmoplegia.

OBJECTIVE: The central pathways responsible for ocular vestibular evoked myogenic potentials (VEMPs) to forehead tapping remain to be determined. This study aimed to determine whether the medial longitudinal fasciculus (MLF) carries the signals for ocular VEMPs (oVEMPs) in response to this mode of stimulation. METHODS: Twelve patients with isolated unilateral internuclear ophthalmoplegia (INO) due to brainstem infarction underwent evaluation of the ocular tilt reaction (ocular torsion and skew deviation), tilt of the subjective visual vertical (SVV), cervical VEMPs (cVEMPs) in response to tone burst sound, and oVEMPs induced by tapping the forehead. RESULTS: Eight (67%) patients showed abnormal oVEMPs that included no wave formation (n=4) and decreased amplitude (n=3) in the lesion side, and bilaterally absent responses in the remaining patient. Furthermore, the patients showed diminished oVEMPs responses in the lesion side compared with normal side (6.0 ± 5.6 vs. 11.7 ± 5.5 µV, paired t-test, p=0.001) and increased IADamp(%) of the oVEMPs compared with normal controls (43.6 ± 41.2 vs. 9.1 ± 6.2, t-test, p=0.018). In contrast, cVEMPs were abnormal in only three (25%) patients, decreased (n=2) or no response in the lesion side. Eleven (92%) patients showed contraversive ocular tilt reaction or SVV tilt. CONCLUSION: Patients with INO frequently show impaired formation of ipsilesional oVEMPs in response to forehead tapping. The occasional abnormality and decreased amplitude of ipsilesional cVEMPs also suggest a modulatory pathway for the inhibitory sacculocollic reflex descending in the MLF. SIGNIFICANCE: This study suggests that the MLF contains the fibers for the otolith-ocular reflex from the contralateral ear.

Neurocysticercosis presenting as isolated wall-eyed monocular internuclear ophthalmoplegia with contraversive ocular tilt reaction.

Neurocysticercosis is a common tropical infection presenting with neurological signs. It commonly presents as seizures but various other focal neurological presentations have been reported. Though neurocysticercosis have been reported to present as isolated internuclear ophthalmoplegia, we report the first case of neurocysticercosis presenting as wall-eyed monoocular internuclear ophthalmoplegia syndrome with contraversive ocular tilt reaction.