Acute vestibulopathy

Acute vestibulopathy is characterized by the acute or subacute onset of vertigo, dizziness or imbalance with or without ocular motor, sensory, postural or autonomic symptoms and signs, and can last for seconds to up to several days. Acute vestibular lesions may result from a hypofunction or from pathological excitation of various peripheral or central vestibular structures (labyrinth, vestibular nerve, vestibular nuclei, cerebellum or ascending pathways to the thalamus and the cortex). This update focuses on new aspects of the aetiology, pathophysiology, epidemiology, and treatment of (i) acute peripheral disorders (benign paroxysmal positioning vertigo, vestibular neuritis, Menière's disease, perilymph fistula, especially 'superior canal dehiscence syndrome', vestibular paroxysmia); and (ii) acute central vestibular disorders (especially 'vestibular migraine'). Finally, the clinical relevance of recent diagnostic tools (three-dimensional analysis of eye movement, imaging techniques) is discussed.     

Central vestibular disorders

Dizziness or vertigo is an erroneous perception of selfmotion or object-motion as well as an unpleasant distortion of static gravitational orientation. It is caused by a mismatch between the vestibular, visual, and somatosensory systems. Thanks to their functional overlap, the three systems are able to compensate, in part, for each other's deficiencies. Thus, vertigo is not a well-defined disease entity, but rather a multisensory syndrome that results when there is a pathological dysfunction of any of the stabilizing sensory systems (e.g., central vestibular disorders, peripheral vestibular diseases with asymmetric input into the vestibular nuclei). This article provides an overview of the most important and frequent forms of central vestibular vertigo syndromes, including basilar/vestibular migraine, which are characterized by ocular motor, postural, and perceptual signs. In a simple clinical classification they can be separated according to the three major planes of action of the vestibulo-ocular reflex: yaw, roll, and pitch. A tonic imbalance in yaw is characterized by horizontal nystagmus, lateropulsion of the eyes, past-pointing, rotational and lateral body falls, and lateral deviation of the perceived straight-ahead. A tonic imbalance in roll is defined by torsional nystagmus, skew deviation, ocular torsion, tilts of head, body, and the perceived vertical. Finally, a tonic imbalance in pitch can be characterized by some forms of upbeat or downbeat nystagmus, fore-aft tilts and falls, and vertical deviation of the perceived straight ahead. The thus defined syndromes allow for a precise topographic diagnosis as regards their level and side.     

Isolated vestibular nuclear infarction: report of two cases and review of the literature

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.     

Medial medullary infarction: report of three patients presented with central vestibular dysfunction without limb and lingual weakness]

The purpose of this article is to draw attention to atypical presentation of medial medullary infarction (MMI). With advanced imaging techniques, small infarctions occurring in the medulla are more easily identified. It is difficult, however, to make a clinical diagnosis of MMI if both hypoglossal nerve palsy and limb weakness are absent, because motor weakness is considered a cardinal manifestation of MMI. We describe here three patients who developed central vestibular dysfunction due to MMI without limb and lingual weakness. Case 1: A 44-year-old, diabetic woman developed vomiting and numbness on her left upper limb. Examination revealed unidirectional horizontal and rotatory nystagmus beating toward the right side. There were no Horner syndrome and hypoglossal nerve palsy. Barré arm and leg signs and limb ataxia were absent. Romberg sign was negative. Hypesthesia was present on her left forearm, hand, and fingers. Thumb-localizing test was normal. Cranial MRI demonstrated an infarction in the right paramedian region of the upper medulla. MR angiography demonstrated irregularity of the basilar and the left vertebral arteries. Case 2: A 69-year-old woman suffered from dizziness and nausea. She showed unidirectional, left-beating horizontal nystagmus. There were no Horner syndrome and hypoglossal nerve palsy, Barré arm and leg signs, and limb ataxia. MRI disclosed an infarction in the left upper medial medulla. Case 3: A 47-year-old man developed vertigo when turning over in bed. He showed left-beating nystagmus without latency, when lying down. Horner syndrome and hypoglossal nerve palsy were absent MRI showed bilateral MMI, with the right lesion being larger than the left. MR angiography demonstrated a stenosis in the distal portion of the left internal carotid artery but not in the vertebral and basilar arteries and their branches. This case represents central positional vertigo. Vestibular syndrome seen in cases 1 and 2 was incomplete and incongruent, suggesting dysfunction of the central vestibular system. There have been only nine cases of MMI with horizontal nystagmus in primary position, including unidirectional horizontorotatory nystagmus. In these cases, horizontal nystagmus beats toward the side of the lesion. In sharp contrast, horizontal nystagmus typically beats away from the lesion side in cases of Wallenberg syndrome, suggesting different underlying mechanism. Unidirectional horizontal and rotatory nystagmus is generally associated with peripheral vestibular dysfunction. There has been no reported case of MMI presenting with vestibular dysfunction preserving motor power. Thus, this "benign" form of MMI might have been misdiagnosed as peripheral vestibular dysfunction before the era of MRI.     

前庭中枢性及周围性眩晕患者视频眼震图参数特点分析

目的 探讨前庭中枢性眩晕和前庭周围性眩晕患者视频眼震图（videonystagmography,VNG）的参数特点。 方法 收集2011年3～12月首都医科大学附属北京天坛医院神经内科住院的69例后循环缺血所致前庭中枢性眩晕患者和眩晕会诊中心就诊的108例前庭周围性眩晕（梅尼埃病12例、良性阵发性位置性眩晕96例）患者的临床资料,分析并比较其VNG参数特点和临床特征。 结果 69例前庭中枢性眩晕患者和108例前庭周围性眩晕患者相比,临床特点：男性多见（P<0.001）,年龄更大（P=0.009）,病程更短（P<0.001）,更多出现视物成双（P<0.001）、偏身麻木无力（P<0.001）、言语不利（P<0.001）等症状,较少出现耳蜗症状（P=0.021）,眩晕持续时间更长（P<0.001）,发病多与体位改变无关（P<0.001）;VNG参数特点：视跟踪异常（40.6% vs 0.9%,P<0.001）、定标试验异常（13.0% vs 0.0%,P<0.001）、视动试验异常（10.1% vs 0.0%,P=0.003）、凝视试验异常（10.1% vs 0.0%,P=0.003）、自发性眼震（8.7% vs 0.0%,P=0.007）或位置性眼震（8.7% vs 0.0%,P=0.007）发生比例前庭中枢性眩晕组高于前庭周围性眩晕组;而变位试验阳性（14.5% vs 74.1%,P<0.001）前庭中枢性眩晕组低于前庭周围性眩晕组。 结论 VNG参数特点能客观地反映前庭中枢性眩晕和前庭周围性眩晕患者的眼震情况,结合临床特征有助于前庭系统性眩晕的定位诊断。     

Bedside Evaluation of Dizzy Patients

In recent decades there has been marked progress in the imaging and laboratory evaluation of dizzy patients. However, detailed history taking and comprehensive bedside neurotological evaluation remain crucial for a diagnosis of dizziness. Bedside neurotological evaluation should include examinations for ocular alignment, spontaneous and gaze-evoked nystagmus, the vestibulo-ocular reflex, saccades, smooth pursuit, and balance. In patients with acute spontaneous vertigo, negative head impulse test, direction-changing nystagmus, and skew deviation mostly indicate central vestibular disorders. In contrast, patients with unilateral peripheral deafferentation invariably have a positive head impulse test and mixed horizontal-torsional nystagmus beating away from the lesion side. Since suppression by visual fixation is the rule in peripheral nystagmus and is frequent even in central nystagmus, removal of visual fixation using Frenzel glasses is required for the proper evaluation of central as well as peripheral nystagmus. Head-shaking, cranial vibration, hyperventilation, pressure to the external auditory canal, and loud sounds may disclose underlying vestibular dysfunction by inducing nystagmus or modulating the spontaneous nystagmus. In patients with positional vertigo, the diagnosis can be made by determining patterns of the nystagmus induced during various positional maneuvers that include straight head hanging, the Dix-Hallpike maneuver, supine head roll, and head turning and bending while sitting. Abnormal smooth pursuit and saccades, and severe imbalance also indicate central pathologies. Physicians should be familiar with bedside neurotological examinations and be aware of the clinical implications of the findings when evaluating dizzy patients.     

Recent advances in central acute vestibular syndrome of a vascular cause

Acute vestibular syndrome (AVS) is characterized by acute onset of spontaneous prolonged vertigo (lasting days), spontaneous nystagmus, postural instability, and autonomic symptoms. Peripheral AVS commonly presents as vestibular neuritis, but may also include other disorders such as Meniere's disease. Vertigo in central AVS due to vertebrobasilar ischemic stroke is usually accompanied by other neurological dysfunction. However it can occur in isolation and mimicking peripheral AVS, particularly with cerebellar strokes. Recent large prospective studies have demonstrated that approximately 11% of patients with isolated cerebellar infarction presented with isolated vertigo mimicking peripheral AVS, and the bedside head impulse test is the most useful tool for differentiating central from peripheral AVS. Herein we review the keys to the diagnosis of central AVS of a vascular cause presenting with isolated vertigo or audiovestibular loss.     

Pharmacotherapy of vestibular and ocular motor disorders,including nystagmus

We review current pharmacological treatments for peripheral and central vestibular disorders, and ocular motor disorders that impair vision, especially pathological nystagmus. The prerequisites for successful pharmacotherapy of vertigo, dizziness, and abnormal eye movements are the “4 D’s”: correct diagnosis, correct drug, appropriate dosage, and sufficient duration. There are seven groups of drugs (the “7 A’s”) that can be used: antiemetics; anti-inflammatory, anti-Ménière’s, and anti-migrainous medications; anti-depressants, anti-convulsants, and aminopyridines. A recovery from acute vestibular neuritis can be promoted by treatment with oral corticosteroids. Betahistine may reduce the frequency of attacks of Ménière’s disease. The aminopyridines constitute a novel treatment approach for downbeat and upbeat nystagmus, as well as episodic ataxia type 2 (EA 2); these drugs may restore normal “pacemaker” activity to the Purkinje cells that govern vestibular and cerebellar nuclei. A limited number of trials indicate that baclofen improves periodic alternating nystagmus, and that gabapentin and memantine improve acquired pendular and infantile (congenital) nystagmus. Preliminary reports suggest suppression of square-wave saccadic intrusions by memantine, and ocular flutter by beta-blockers. Thus, although progress has been made in the treatment of vestibular neuritis, some forms of pathological nystagmus, and EA 2, controlled, masked trials are still needed to evaluate treatments for many vestibular and ocular motor disorders, including betahistine for Ménière’s disease, oxcarbazepine for vestibular paroxysmia, or metoprolol for vestibular migraine.     

The effect of nicotine on perceptual, ocular motor, postural, and vegetative functions at rest and in motion

Nicotine has wellknown, unpleasant side effects, e.g., transient dizziness, nausea, and nicotine-induced nystagmus (NIN). To investigate factors influencing these effects, we addressed three questions: (1) Is the intensity of dizziness, nausea, NIN, and unsteadiness dependent on nicotine dosage? (2) Does the intensity of perceptual, ocular motor, vegetative effects, and postural imbalance correlate? (3) Do visual or vestibular motion stimuli produce and/or aggravate distressing dizziness and nausea? Sixty healthy non-smokers or occasional smokers participated; 40 were tested once before and six times after application of a nicotine nasal spray in doses of 1 mg or 2 mg with or without motion stimulation; 20 received a placebo nasal spray. Plasma nicotine concentrations were significantly related to nicotine dosage. Dizziness, nausea, NIN, and unsteadiness also depended on the nicotine dosage (p < 0.01).Nicotine blood concentration was a better predictor for the temporal dependence of nystagmus than nicotine dosage.Dizziness correlated highly with nausea (R = 0.63, p < 0.001). The degree of nicotine-induced nausea significantly correlated with postural imbalance. The time course of postural sway differed according to nicotine dosage and gender: for women, there was no clear relationship between sway magnitude and nicotine dosage, while men showed increased sway with higher dosage.Motion stimulation increased nicotine-induced dizziness and nausea, but did not significantly influence NIN or postural imbalance. Our data support the view that all measured adverse effects reflect dose-dependent nicotine-induced vestibular dysfunction. Additional motion stimulation aggravates dizziness and nausea, i.e., nicotine increases sensitivity to motion sickness.     

Positional and positioning vertigo and nystagmus

Positional and positioning vertigo and nystagmus syndromes can be attributed to either peripheral or central vestibular dysfunction. The most common form is benign paroxysmal positioning vertigo which is caused by cupulolithiasis into the posterior semicircular canal. Other labyrinthine manifestations such as positional alcohol nystagmus, positional nystagmus with macroglobulinaemia and "heavy water" or glycerol ingestion occur because of a specific gravity differential between the cupula and the endolymph (buoyancy mechanism). Neurovascular compression of the vestibular nerve may be a causative factor for "disabling positional vertigo" which is an insufficiently described entity. Hesitation is highly justifiable since retromastoid craniectomy for microvascular decompression is the recommended management. Central positional vertigo is either induced by head movements which result in a transient ischaemia of the ponto-medullary brainstem, or by a change in head position relative to the gravitational vector. The latter is comprised of at least three forms: positional downbeat nystagmus (nodulus), positional nystagmus without concurrent vertigo, and positional vertigo with nystagmus. The site of the lesion is always near the fourth ventricle and the vestibular nuclei. The most probable explanation for the positional response is a vestibular tone imbalance caused by disinhibition of the vestibular reflexes on perception, eye, head and body position.     

Mastication-induced vertigo and nystagmus

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.     

Perceived vertical and lateropulsion: clinical syndromes, localization, and prognosis

We present a clinical classification of central vestibular syndromes according to the three major planes of action of the vestibulo-ocular reflex: yaw, roll, and pitch. The plane-specific syndromes are determined by ocular motor, postural, and perceptual signs. Yaw plane signs are horizontal nystagmus, past pointing, rotational and lateral body falls, deviation of perceived straight-ahead to the left or right. Roll plane signs are torsional nystagmus, skew deviation, ocular torsion, tilts of head, body, and perceived vertical in a clockwise or counterclockwise direction. Pitch plane signs are upbeat/downbeat nystagmus, forward/backward tilts and falls, deviations of the perceived horizon. The thus defined vestibular syndromes allow a precise topographic analysis of brainstem lesions according to their level and side. Special emphasis is placed on the vestibular roll plane syndromes of ocular tilt reaction, lateropulsion in Wallenberg's syndrome, thalamic and cortical astasia and their association with roll plane tilt of perceived vertical. Recovery is based on a functionally significant central compensation of a vestibular tone imbalance, the mechanism of which is largely unknown. Physical therapy may facilitate this central compensation, but this has not yet been proven in prospective studies.     

Diagnosis and treatment of the most frequent vestibular syndromes

The aims of this study were to identify the most common vestibular syndromes in a dizziness unit, and to observe their clinical aspects and response to treatment. Five hundred and fifteen patients were studied retrospectively in two institutions. Aspects of anamnesis, physical examination and the response to treatment were evaluated. The most frequent syndromes were: benign paroxysmal positioning vertigo (VPPB) (28.5%), phobic postural vertigo (11.5%), central vertigo (10.1%), vestibular neuritis (9.7%), Meniere disease (8.5%), and migraine (6.4%). A good response to treatment was observed in most patients with migraine (78.8%), VPPB (64%), vestibular neuritis (62%), Meniere disease (54.5%) and vestibular paroxismia (54.5%). On the other hand, patients with downbeat nystagmus and bilateral vestibulopathy had poor response (52.6% and 42.8%, respectively). The diagnosis of these most frequent vestibular syndromes were established through anamnesis and physical examination (with specific clinical tests for evaluation of the vestibular function). The correct diagnosis and adequate treatment are important since these syndromes may have a good prognosis.     

Pharmacological advances in the treatment of neuro-otological and eye movement disorders

PURPOSE OF REVIEW: First, to describe the current pharmacological treatment options for peripheral and central vestibular, cerebellar, and ocular motor disorders. Second, to identify vestibular and ocular motor disorders in which treatment trials are warranted. RECENT FINDINGS: Peripheral vestibular disorders: In vestibular neuritis recovery of the peripheral vestibular function can be improved by treatment with oral corticosteroids. In Ménière's disease treatment strategies range from low-salt diet, diuretics, and betahistine, to intratympanic injection of corticosteroids or gentamicin. Unfortunately most of the trials on Ménière's disease do not have an up-to-date design. In bilateral vestibulopathy steroids do not seem to improve vestibular function.Central vestibular, cerebellar, and ocular motor disorders: The use of aminopyridines introduced a new therapeutic principle in the treatment of downbeat and upbeat nystagmus and episodic ataxia type 2 (EA2). These potassium channel blockers presumably increase the activity and excitability of cerebellar Purkinje cells, thereby augmenting the inhibitory influence of these cells on vestibular and cerebellar nuclei. A few studies showed that baclofen improves periodic alternating nystagmus, and gabapentin and memantine, pendular nystagmus. Many other eye movement disorders, however, such as ocular flutter, opsoclonus, central positioning, or see-saw nystagmus are still difficult to treat. SUMMARY: Although progress has been made in the treatment of vestibular neuritis, downbeat and upbeat nystagmus, as well as EA2, state-of-the-art trials must still be performed on many vestibular and ocular motor disorders, namely Ménière's disease, bilateral vestibulopathy, vestibular paroxysmia, vestibular migraine, and many forms of central eye movement disorders.     

表现为孤立性眩晕的大脑中动脉穿支梗死

目的孤立性眩晕主要见于前庭周围性病变,罕见于大脑中动脉(MCA)穿支脑梗死,本文探讨MCA穿支梗死出现孤立性眩晕与头晕的临床特征。方法报道3例表现为孤立性眩晕和头晕的MCA穿支急性腔隙性脑梗死患者的临床表现、影像学资料,同时通过PubMed检索之前报道的病例,回顾总结其临床特征。结果包括文献共5例表现为眩晕和头晕的MCA穿支梗死病例。3例表现为孤立性眩晕和头晕,1例表现为持续性头晕伴随短暂性言语不清,1例有轻偏瘫,2例有眼球震颤。眩晕与头晕严重程度均为中度,经治疗后眩晕和头晕多在病程7 d内完全缓解。4例梗死灶位于左侧内囊或放射冠区,1例位于右侧放射冠。颈部及头部增强血管成像有2例显示右侧椎动脉纤细狭窄,4例完成了头部增强CTA检查均提示前循环血管正常。本文3例患者在核磁共振成像(MRI)检查证实为急性腔隙性脑梗死之前,均未有明确诊断。结论 MCA穿支脑梗死可以表现为孤立性眩晕和头晕,严重程度较轻,持续时间通常数日,自主神经症状不明显。为了避免漏诊或误诊,推荐神经影像学检查,特别是MRI弥散成像(DWI)可作为老年首次眩晕和头晕的常规检查项目。     

Episodic vertigo related to migraine (90 cases): vestibular migraine?

A retrospective study was conducted on 90 patients with episodic vertigo that could be related to migraine as the most probable pathomechanism. Since the majority of the patients did not fulfill the criteria of the International Headache Society (IHS) for basilar migraine, the diagnosis was substantiated by disease course, medical efficacy in treating (ergotamines) and preventing (metoprolol, flunarizine) attacks, ocular motor abnormalities in the symptom-free interval, and careful exclusion of the most relevant differential diagnoses, such as transient ischemic attacks, Menière’s disease, and vestibular paroxysmia. The following clinical features were elaborated. The initial manifestation could occur at any time throughout life, with a peak in the fourth decade in men and a “plateau” between the third and fifth decades in women. The duration of rotational (78%) and/or to-and-fro vertigo (38%) could last from a few seconds to several hours or, less frequently, even days; duration of a few minutes or of several hours was most frequent. Monosymptomatic audiovestibular attacks (78%) occurred as vertigo associated with auditory symptoms in only 16%. Vertigo was not associated with headache in 32% of the patients. In the symptom-free interval 66% of the patients showed mild central ocular motor signs such as vertical (48%) and/or horizontal (22%) saccadic pursuit, gaze-evoked nystagmus (27%), moderate positional nystagmus (11%), and spontaneous nystagmus (11%). Combinations with other forms of migraine were found in 52%. Thus, migraine is a relevant differential diagnosis for episodic vertigo. According to the criteria of the IHS, only 7.8% of these patients would be diagnosed as having basilar migraine. However, to ensure that at least those presenting with monosymptomatic episodic vertigo (78% in our study) receive effective treatment, we propose the use of the more appropriate term “vestibular migraine.” Received: 22 September 1998 Received in revised form: 3 March 1999 Accepted: 16 March 1999     

Assessing vestibular function: which tests, when?

Vertigo and dizziness are common complaints encountered in clinical practice. The patient’s history and a thorough otoneurological evaluation are essential for identifying the specific pathology behind the patient’s complaints. If the patient reports an illusion of movement (vertigo), this most likely indicates an imbalance within the vestibular system. A sensation of rotatory movement together with a spontaneous nystagmus suggests a lesion involving the semicircular canals, while an illusion of linear movement indicates a disturbance of the otoliths. Nystagmus of central origin or caused by a peripheral vestibular lesion can usually be distinguished by other features in the history or on clinical examination. While peripheral vestibular lesions usually lead to a mixed horizontal-torsional or vertical-torsional nystagmus, a pure vertical or pure torsional nystagmus is always caused by a central lesion. With simple bedside tests such as head-shaking nystagmus and rapid head impulses deficits in labyrinthine function can clearly be detected. For a more thorough investigation of vestibular function at the level of individual semicircular canals and the otoliths, modern techniques are now available such as three-dimensional eye movement vector analysis for the evaluation of individual semicircular canal function, measurement of the subjective visual vertical for utricular, and click-evoked myogenic potentials for saccular testing. Received: 3 October 1999/Accepted: 7 December 1999     

Vision and vertigo

This review deals with two syndromes, oscillopsia and visual vertigo. Oscillopsia is the illusion of oscillation of the visual surroundings. For diagnosis purposes one should ask, when does the oscillopsia occur? If oscillopsia is only present during head (or whole body) movements, the likely underlying cause is a bilateral defect in the vestibulo-ocular reflex (VOR). The more common causes are post meningitic vestibular damage, gentamicin ototoxicity or bilateral idiopathic vestibular failure. When oscillopsia develops after specific head positions, it is usually due to a positional nystagmus, usually the result of brainstem-cerebellar disease. When the oscillopsia is largely unrelated to head movements, one should ask, is it fairly constant or is it in attacks (paroxysmal)? If the oscillopsia is constant it is usually due to the presence of a clinically observable nystagmus; the most common is downbeat nystagmus but the most visually disabling is pendular nystagmus. If the oscillopsia comes in brief attacks it is usually due to a paroxysmal nystagmus as observed in irritative VIII nerve and brainstem lesions. However, the most common cause of paroxysmal oscillopsia is a non organic condition called voluntary nystagmus. Treatment of oscillopsia is often pharmacological but disappointing; the best chance of success is carbamazepine for paroxysmal disorders secondary to structural vestibular nerve/nuclear lesions.Visual vertigo should not be confused with oscillopsia. It can be defined as dizziness provoked by visual environments with large size (full field) repetitive or moving visual patterns. Patients with visual vertigo report discomfort in supermarkets and when viewing movement of large visual objects, eg crowds, traffic, clouds or foliage. Visual vertigo is present in many patients with a history of a peripheral vestibular disorder, particularly those who are visually dependent (ie subjects who use vision preferentially for postural and space orientation control). Patients with visual vertigo benefit from the addition to their standard vestibular rehabilitation of optic flow (optokinetic) stimuli and exercises involving visuo-vestibular conflict.     

Multiple sclerosis as a cause of the acute vestibular syndrome

Multiple sclerosis (MS) causes dizziness and vertigo. Reports suggest responsible lesions are often in the intra-pontine 8th nerve fascicle. We sought to determine frequency and clinical features of demyelinating acute vestibular syndrome (AVS). This is a prospective observational study (1999–2011). Consecutive AVS patients (vertigo, nystagmus, nausea/vomiting, head-motion intolerance, unsteady gait) with a risk for central localization underwent structured bedside examination and neuroimaging. When applicable, we identified MS based on clinical, imaging, and laboratory features. Of 170 AVS presentations, 4 % (n = 7) were due to demyelinating disease. Five had an acute MS plaque likely responsible for the clinical syndrome. Lesion location varied—1 medulla; 1 inferior cerebellar peduncle; 1 middle cerebellar peduncle; 1 posterior pontine tegmentum; 1 in the intrapontine 8th nerve fascicle; 1 superior cerebellar peduncle; 1 midbrain. Only two had a lesion in or near the intra-pontine 8th nerve fascicle. Three were first presentations (i.e., clinically isolated demyelinating syndrome), while the others were known MS. All had central oculomotor signs. In two patients, the only central sign was a normal horizontal head impulse test (h-HIT) of vestibular function. All patients improved with steroid therapy. Demyelinating disease was an uncommon cause of AVS in our series. Symptomatic lesions were not restricted to the 8th nerve fascicle. Five patients had relatively obvious oculomotor signs, making differentiation from vestibular neuritis straightforward. Two patients had unidirectional, horizontal nystagmus that followed Alexander’s law and was suppressed with fixation (true pseudoneuritis). The presence of a normal h-HIT in these suggested central localization.     

Congenital and compensated vestibular dysfunction in childhood: an overlooked entity

We report five children with previously unrecognized vestibular dysfunction detected by clinical examination and confirmed by quantitative vestibular testing. Patient 1 presented with fluctuating visual acuity and intermittent nystagmus. Patient 2 had congenital hearing loss associated with imbalance, delayed motor development, and cyclic vomiting. Patient 3 had neurotrophic keratitis with an intermittent head tilt, imbalance, and motor delays. Patient 4 showed ataxia and eye movement abnormalities following traumatic brain injury and had reading difficulties. Patient 5 had episodic vertigo and eye movement abnormalities from infancy. Clinical vestibular testing emphasized spontaneous nystagmus, rapid head thrust, and assessment of post-rotatory nystagmus. Quantitative vestibular testing included the sinusoidal chair rotation and velocity step tests, measurement of dynamic visual acuity, post-head-shake nystagmus, and computerized platform posturography. Pediatric neurologists encounter children with congenital and compensated vestibular dysfunction, which can be recognized on the basis of relevant history and clinical abnormalities of the ocular-ocular reflex.