Magnetic resonance brain imaging in patients with visual vertigo

Concussed patients with visually induced dizziness exhibit increased ocular torsion and vertical vergence during optokinetic gaze-stabilization

Visually Induced Dizziness (VID) is a common post-concussion sequalae that remains poorly understood and difficult to quantify. The present study aims to identify biomarkers for VID in the form of gaze-stabilizing eye movements. Nine patients with post-commotio VID and nine age-matched healthy controls were recruited by physiotherapists at a local neurorehabilitation centre. Torsional and vergence eye movements were recorded while participants viewed a series of optokinetic rotations where the central- and peripheral regions moved coherently, incoherently, or semi-randomly. Results showed that vergence and torsional velocities were increased in VID patients, reflecting increased oculomotor gain to visual motion, and that responses correlated with symptom severity. Coherent stimulation produced fastest torsional slow-phases across all participants; when faced with confliction directional information, eye movements tended to follow the direction of the central visual field, albeit at slower velocities than during coherent motion, meaning that while torsion was sensitive to visual content of the entire visual field it expressed directional preference to the central stimulation. In conclusion, post-commotio VID was associated with faster slow-phases during optokinetic gaze-stabilization, with both vergence and torsion being correlated to symptom intensity. As torsional tracking remains inaccessible using commercial eye-trackers, vertical vergence may prove particularly accessible for clinical utility.

Development of cognition decline in non-acute symptomatic patients with cerebral small vessel disease: Non-Acute Symptomatic Cerebral Ischemia Registration study (NASCIR)-rationale and protocol for a prospective multicentre observational study

INTRODUCTION

Headaches, dizziness and memory loss of unspecific causes are the most common non-acute ischemia symptoms in the ageing population, which are often associated with cerebral small vessel disease (CSVD) imaging markers; however, there is insufficient evidence concerning their association with the development of cognitive decline. This study aims to investigate risk factors, clinical course, cerebral and retinal imaging changes, proteomics features of non-symptomatic ischaemia symptomatic patients with cognitive decline.

METHODS AND ANALYSIS

The Non-Acute Symptomatic Cerebral Ischemia Registration study is a multicentre, registry-based, prospective observational study, is designed to investigate the cognitive decline in non-acute ischaemia symptomatic patients. We will recruit 500 non-acute ischaemia symptomatic patients from four tertiary hospitals in China. For this study, non-acute ischaemia symptoms will be defined as headaches, dizziness and memory loss. Patients with headaches, dizziness or memory loss over 50 years of age will be included. Clinical features, cognitive assessment, cerebral and retinal imaging data, and a blood sample will be collected after recruitment. Patients will be followed up by structured telephone interviews at 1, 2, 3, 4, 5 years after recruitment. This study will improve our knowledge of the development of cognitive decline in non-acute ischaemia symptomatic patients and factors affecting the cognitive outcomes, which will eventually elucidate underlying pathways and mechanisms of cognitive decline in these patients and facilitate the optimisation of individualised interventions for its prevention and treatment.

ETHICS AND DISSEMINATION

Ethics approval is obtained from The Biomedical Research Ethics Committee of West China Hospital, Sichuan University (Reference No. 2016 (335)). We will present our findings at national and international conferences and peer-reviewed journals in stroke and neurology.

TRIAL REGISTRATION NUMBER

ChiCTR-COC-17013056.

Neuroimaging Systematic Review in Persistent Postural-Perceptual Dizziness: The Elaborate Alterations in the Delicate Network to Remain Balanced

OBJECTIVES

Persistent postural-perceptual dizziness (PPPD) is a chronic functional vestibular disorder that may have normal physical examination, clinical laboratory testing and vestibular evaluation. However, advances in neuroimaging have provided new insights in brain functional connectivity and structure in patients with PPPD. This systematic review was aimed at identifying significant structural or alterations in functional connectivity in patients with PPPD.

DATABASES REVIEWED

Science Direct, Pubmed, Embase via Ovid databases, and Cochrane library.

METHODS

This review following the guidelines of PRISMA, systematically and independently examined papers published up to March 2021 which fulfilled the predetermined criteria. PROSPERO Registration (CRD42020222334).

RESULTS

A total of 15 studies were included (MRI = 4, SPECT = 1, resting state fMRI = 4, task-based fMRI = 5, task-based fMRI + MRI = 1). Significant changes in the gray matter volume, cortical folding, blood flow, and connectivity were seen at different brain regions involved in vestibular, visual, emotion, and motor processing.

CONCLUSION

There is a multisensory dimension to the impairment resulting in chronic compensatory changes in PPPD that is evident by the significant alterations in multiple networks involved in maintaining balance. These changes observed offer some explanation for the symptoms that a PPPD patient may experience.Systematic Review Registration: This study is registered with PROSPERO (CRD42020222334).

Visual stress responses to static images are associated with symptoms of Persistent Postural Perceptual Dizziness (PPPD)

BACKGROUND

Images that deviate from natural scene statistics in terms of spatial frequency and orientation content can produce visual stress (also known as visual discomfort), especially for migraine sufferers. These images appear to over-activate the visual cortex.

OBJECTIVE

To connect the literature on visual discomfort with a common chronic condition presenting in neuro-otology clinics known as persistent postural perceptual dizziness (PPPD). Patients experience dizziness when walking through highly cluttered environments or when watching moving stimuli. This is thought to arise from maladaptive interaction between vestibular and visual signals for balance.

METHODS

We measured visual discomfort to stationary images in patients with PPPD (N = 30) and symptoms of PPPD in a large general population cohort (N = 1858) using the Visual Vertigo Analogue Scale (VVAS) and the Situational Characteristics Questionnaire (SCQ).

RESULTS

We found that patients with PPPD, and individuals in the general population with more PPPD symptoms, report heightened visual discomfort to stationary images that deviate from natural spectra (patient comparison, F (1, 1865) = 29, p < 0.001; general population correlations, VVAS, rs (1387) = 0.46, p < 0.001; SCQ, rs (1387) = 0.39, p < 0.001). These findings were not explained by co-morbid migraine. Indeed, PPPD symptoms showed a significantly stronger relationship with visual discomfort than did migraine (VVAS, zH = 8.81, p < 0.001; SCQ, zH = 6.29, p < 0.001).

CONCLUSIONS

We speculate that atypical visual processing -perhaps due to a visual cortex more prone to over-activation -may predispose individuals to PPPD, possibly helping to explain why some patients with vestibular conditions develop PPPD and some do not.

Potential risk factors of persistent postural-perceptual dizziness: a pilot study

BACKGROUND

Persistent postural-perceptual dizziness (PPPD) unifies the main characteristics of chronic subjective dizziness, visual vertigo and related diseases, which is a common chronic disease in neurology. At present, the pathology of PPPD is not fully understood.

OBJECTIVE

In this single-center retrospective case series review, we aim to investigate the potential risk factors of PPPD.

METHODS

Eighty inpatients diagnosed with PPPD were recruited with 81 apparently healthy controls. Patient-specific clinico-radiological data were collected from both groups. Conditions of hypertension, diabetes, smoking, and drinking were derived from medical history. Blood test results were recorded including total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fibrinogen, vitamin B12, folic acid, total cholesterol, triglyceride, and folate level. The subjects were examined by carotid artery CTA and cranial MRI, and the imaging findings of carotid atherosclerosis (CAS), white matter hyperintensities (WMHs) and lacunar infarction (LI) were recorded. Binary logistic regression analysis was used to investigate the difference between the case and control groups. Significance was defined as p value less than 0.05.

RESULTS

The prevalence rate of hypertension in the case group was significantly higher than that in the control group, and the detection rates of CAS, WMHs, and LI in the case group were significantly higher than those in the control group (p < 0.05 for all).

CONCLUSION

Hypertension, CAS, WMHs, and LI are associated with PPPD, which may be potential risk factors for its development.

Neuroimaging studies in persistent postural-perceptual dizziness and related disease: a systematic review

BACKGROUND

Persistent Postural-Perceptual Dizziness (PPPD) is one of the most common types of chronic dizziness. The pathogenesis remains unclear.

OBJECTIVE

This study aimed to systematically review neuroimaging literature for investigating the central mechanism of PPPD and related disorders.

METHODS

PubMed, EMBASE, Medline, Cochrane, and Web of Science were searched by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The articles analyzing structural and functional neuroimaging features of PPPD and related disorders were selected according to eligibility criteria.

RESULTS

Fifteen articles, including 4 structural, 10 functional, and 1 multimodal imaging, were eligible for inclusion in this review. The whiter matter alterations in PPPD are not entirely consistent. The changes of grey matter mainly in multisensory vestibular cortices, visual cortex, cerebellum, as well as anxiety-related network. Consistent with structural imaging, functional imaging conducted during the specific tasks or in the resting state has both found abnormal functional activation and connectivity in the vestibular cortex, especially in the parieto-insular vestibular cortex (PIVC), visual cortex, cerebellum, and anxiety-related network in PPPD and related disorder.

CONCLUSIONS

The current review provides up-to-date knowledge and summarizes the possible central mechanism for PPPD and related disorders, and it is helpful to understanding the mechanism of PPPD.

Persistent postural perceptual dizziness is on a spectrum in the general population

Objective

To examine the idea that symptoms of persistent postural perceptual dizziness (PPPD) are more common than previously assumed and lie on a spectrum in the general population, thus challenging current theories that PPPD is only a consequence of a vestibular insult.

Methods

We collected 2 common clinical questionnaires of PPPD (Visual Vertigo Analogue Scale [VVAS] and Situational Characteristics Questionnaire [SCQ]) in 4 cohorts: community research volunteers (n = 1941 for VVAS, n = 1,474 for SCQ); paid online participants (n = 190 for VVAS, n = 125 for SCQ); students (n = 204, VVAS only); and patients diagnosed with PPPD (n = 25).

Results

We found that around 9%, 4%, and 11%, respectively, of the 3 nonclinical cohorts scored above the 25th percentile patient score on 1 PPPD measure (VVAS) and 49% and 54% scored above the 25th percentile patient score on the other measure (SCQ). Scores correlated negatively with age (counter to expectation). As expected, scores correlated with migraine in 2 populations, but this only explained a small part of the variance, suggesting that migraine is not the major factor underlying the spectrum of PPPD symptoms in the general population.

Conclusion

We found high levels of PPPD symptoms in nonclinical populations, suggesting that PPPD is a spectrum that preexists in the population, rather than only being a consequence of vestibular insult. Atypical visuo-vestibular processing predisposes some individuals to visually induced dizziness, which is then exacerbated should vestibular insult (or more generalized insult) occur.

Changes in Cortical Activation During Dual-Task Walking in Individuals With and Without Visual Vertigo

BACKGROUND AND PURPOSE

Persons with vestibular disorders are known to have slower gait speed with greater imbalance and veering during dual-task walking than healthy individuals, but the cerebral mechanisms are unknown. The purpose of this study was to determine whether individuals with visual vertigo (VV) have different cerebral activation during dual-task walking compared with control subjects.

METHODS

Fourteen individuals with VV and 14 healthy controls (CON) were included (mean 39 years old, 85% women). A cross-sectional experimental study consisting of 4 combinations of 2 surfaces (even and uneven) and 2 task conditions (single- and dual-task) was performed. Participants walked over an even (level flooring) or uneven (wood prisms underneath carpeting) surface, either quietly or while reciting every other letter of the alphabet. Changes in cerebral activation over the bilateral prefrontal cortices were recorded using functional near-infrared spectroscopy during 4 task conditions relative to quiet standing. Gait speed and cognitive performance were recorded.

RESULTS

There were no between-group differences in cognitive performance. Both groups slowed when walking on an uneven surface or performing a dual-task; participants in the VV group walked more slowly than those in the CON group in all conditions. Participants with VV had decreased cerebral activation in the bilateral prefrontal regions in comparison to CON participants in all conditions.

DISCUSSION AND CONCLUSIONS

Participants with VV had lower prefrontal cortex activation than CON participants during dual-task walking. Lower cortical activity in those with VV may be due to shifted attention away from the cognitive task to prioritize maintenance of dynamic balance.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A303).

A case-control study of visually evoked postural responses in childhood with primary headaches

BACKGROUND

Disorientation, nausea, confusion, dizziness, and displacement are frequently complained by headache-suffering children. Anyhow, the cause of these symptoms is still unclear, and a dysfunction of vestibular pathways or their alteration due to central pain pathways hyper-activation, has been proposed. The aim of this study is to use posturography to explore the balance function of headache-suffering children during pain-free periods.

METHODS

Posturography was performed on 19 migraineurs, 11 tension-type headache sufferers, and 20 healthy controls. Posturographic measures were performed during headache-free periods under different conditions: with eyes opened, eyes closed, and during right and left optokinetic stimulation. The last 2 conditions were used to mimic unreliable visual signals that can confound vestibular system.

RESULTS

During eyes-closed conditions, headache-suffering children displayed higher displacements than healthy controls, since statokinesiogram surface was higher in tension-type headache sufferers and migraineurs compared with controls (P value = 0.0095). Romberg's index, indicating the overall stability of the subject, was lower in healthy controls than in headache sufferers (P = 0.0139), thus suggesting a vestibular impairment in the seconds. Moreover, both during right and left optokinetic stimulation, the statokinesiogram length was higher in headache-suffering children (P < 0.0001). Thereafter, statokinesiogram surface was higher in migraineurs during right optokinetic stimulation (P = 0.0388) than in tension-type headache sufferers when stimulation was directed on the opposite side (P = 0.0249).

CONCLUSIONS

These results suggest a central alteration of vestibular pathways in headache-suffering children, that makes balance function more dependent from visual inputs than healthy subjects, even in inter-ictal phases.

Perceptual Postural Imbalance and Visual Vertigo

PURPOSE OF REVIEW

Disorders of posture and balance cause significant patient morbidity, with reduction of quality of life as patients refrain from critical activities of daily living such as walking outside the home and driving. This review describes recent efforts to characterize visual disorders that interact with the neural integrators of positional maintenance and emerging therapies for these disorders.

RECENT FINDINGS

Abnormalities of gait and body position sense may be unrecognized by patients but are correlated with focal neurological injury (stroke). Patients with traumatic brain injury can exhibit visual vertigo despite otherwise normal visual functioning. The effect of visual neglect on posture and balance, even in the absence of a demonstrable visual field defect, has been characterized quantitatively through gait analysis and validates the potential therapeutic value of prism treatment in some patients. In addition, the underlying neural dysfunction in visual vertigo has been explored further using functional imaging, and these observations may allow discrimination of patients with structural causes from those whose co-morbid psychosocial disorders may be primarily contributory.

Changes in cerebral activation in individuals with and without visual vertigo during optic flow: A functional near-infrared spectroscopy study

Background and purpose

Individuals with visual vertigo (VV) describe symptoms of dizziness, disorientation, and/or impaired balance in environments with conflicting visual and vestibular information or complex visual stimuli. Physical therapists often prescribe habituation exercises using optic flow to treat these symptoms, but it is not known how individuals with VV process the visual stimuli. The primary purpose of this study was to use functional near-infrared spectroscopy (fNIRS) to determine if individuals with VV have different cerebral activation during optic flow compared with control subjects.

Methods

Fifteen individuals (5 males and 10 females in each group) with VV seeking care for dizziness and 15 healthy controls (CON) stood in a virtual reality environment and viewed anterior-posterior optic flow. The support surface was either fixed or sway-referenced. Changes in cerebral activation were recorded using fNIRS during periods of optic flow relative to a stationary visual environment. Postural sway of the head and center of mass was recorded using an electromagnetic tracker.

Results

Compared with CON, the VV group displayed decreased activation in the bilateral middle frontal regions when viewing optic flow while standing on a fixed platform. Despite both groups having significantly increased activation in most regions while viewing optic flow on a sway-referenced surface, the VV group did not have as much of an increase in the right middle frontal region when viewing unpredictable optic flow in comparison with the CON group.

Discussion and conclusions

Individuals with VV produced a pattern of reduced middle frontal cerebral activation when viewing optic flow compared with CON. Decreased activation in the middle frontal regions of the cerebral cortex may represent an alteration in control over the normal reciprocal inhibitory visual-vestibular interaction in visually dependent individuals. Although preliminary, these findings add to a growing body of literature using functional brain imaging to explore changes in cerebral activation in individuals with complaints of dizziness, disorientation, and unsteadiness. Future studies in larger samples should explore if this decreased activation is modified following a rehabilitation regimen consisting of visual habituation exercises.

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Visual vertigo and healthy controls process optic flow information differently.

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Visual vertigo had reduced bilateral middle frontal activation on a fixed platform.

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Visual vertigo had reduced right middle frontal activation on a moving platform.

Development and Validation of the Vision-Related Dizziness Questionnaire

Purpose

To develop and validate the first patient-reported outcome measure (PROM) to quantify vision-related dizziness. Dizziness is a common, multifactorial syndrome that causes reductions in quality of life and is a major risk factor for falls, but the role of vision is not well understood.

Methods

Potential domains and items were identified by literature review and discussions with experts and patients to form a pilot PROM, which was completed by 335 patients with dizziness. Rasch analysis was used to determine the items with good psychometric properties to include in a final PROM, to check undimensionality, differential item functioning, and to convert ordinal questionnaire data into continuous interval data. Validation of the final 25-item instrument was determined by its convergent validity, patient, and item-separation reliability and unidimensionality using data from 223 patients plus test–retest repeatability from 79 patients.

Results

120 items were originally identified, then subsequently reduced to 46 to form a pilot PROM. Rasch analysis was used to reduce the number of items to 25 to produce the vision-related dizziness or VRD-25. Two subscales of VRD-12-frequency and VRD-13-severity were shown to be unidimensional, with good psychometric properties. Convergent validity was shown by moderately good correlations with the Dizziness Handicap Inventory (r = 0.75) and good test–retest repeatability with intra-class correlation coefficients of 0.88.

Conclusion

VRD-25 is the only PROM developed to date to assess vision-related dizziness. It has been developed using Rasch analysis and provides a PROM for this under-researched area and for clinical trials of interventions to reduce vision-related dizziness.

Lack of association of MRI determined subclinical cardiovascular disease with dizziness and vertigo in a cross-sectional population-based study

Objective

We investigated the association between subclinical cardiovascular diseases assessed by MRI examination and symptoms of dizziness and vertigo in participants of a population-based sample.

Methods

Data from 400 participants (169 women) aged from 39 to 73 of a cross-sectional MRI sub-study of the “Kooperative Gesundheitsforschung in der Region Augsburg” (KORA) FF4 study from the south of Germany was used. MRI determined subclinical cardiovascular diseases include left and right ventricular structure and function as well as the presence of carotid plaque and carotid wall thickness. Cerebrum diseases include white matter lesions (WML) and cerebral microbleeds (CMB). The main outcomes of dizziness and vertigo were assessed by standardized interview. Logistic regression models were applied and adjusted odds ratios (OR) with 95% confidence intervals (CI) were provided.

Results

Lifetime and 12-month prevalence of dizziness and vertigo were 30% (95%CI 26% to 35%) and 21% (95%CI 17% to 26%) respectively in this sample. On multivariable analysis, cardiac and carotid measurements were not associated with dizziness and vertigo excluding orthostatic vertigo (20%, 95CI 16% to 24%). Only in male participants, there was a significant association between WML and the presence of dizziness and vertigo (OR = 2.95, 95%CI 1.08 to 8.07). There was no significant association of CMB with dizziness and vertigo.

However, CMB and WML were tending to associate with a higher risk of dizziness and vertigo in the whole sample (CMB: OR = 1.48, 95%CI 0.70; 3.15; WML: OR = 1.71, 95%CI 0.80 to 3.67;), in persons with prediabetes and diabetes (WML: OR = 2.71, 95%CI 0.89 to 8.23) and in men with normal glucose metabolism (CMB: OR = 2.60, 95%CI 0.56 to 12.0; WML: OR = 3.08, 95%CI 0.58 to 16.5).

Conclusions

In this sample of participants without manifest cardiovascular diseases, subclinical left and right ventricular function and carotid structure were consistently not associated with dizziness and vertigo. Subclinical cerebrum measurements, however, tend to increase the risk for dizziness and vertigo, especially in men and in persons with prediabetes or diabetes.

Altered functional brain connectivity in patients with visually induced dizziness

Background

Vestibular patients occasionally report aggravation or triggering of their symptoms by visual stimuli, which is called visually induced dizziness (VID). These patients therefore experience dizziness, discomfort, disorientation and postural unsteadiness. The underlying pathophysiology of VID is still poorly understood.

Objective

The aim of the current explorative study was to gain a first insight in the underlying neural aspects of VID.

Methods

We included 10 VID patients and 10 healthy matched controls, all of which underwent a resting state fMRI scan session. Changes in functional connectivity were explored by means of the intrinsic connectivity contrast (ICC). Seed-based analysis was subsequently performed in visual and vestibular seeds.

Results

We found a decreased functional connectivity in the right central operculum (superior temporal gyrus), as well as increased functional connectivity in the occipital pole in VID patients as compared to controls in a hypothesis-free analysis. A weaker functional connectivity between the thalamus and most of the right putamen was measured in VID patients in comparison to controls in a seed-based analysis. Furthermore, also by means of a seed-based analysis, a decreased functional connectivity between the visual associative area and the left parahippocampal gyrus was found in VID patients. Additionally, we found increased functional connectivity between thalamus and occipital and cerebellar areas in the VID patients, as well as between the associative visual cortex and both middle frontal gyrus and precuneus.

Conclusions

We found alterations in the visual and vestibular cortical network in VID patients that could underlie the typical VID symptoms such as a worsening of their vestibular symptoms when being exposed to challenging visual stimuli. These preliminary findings provide the first insights into the underlying functional brain connectivity in VID patients. Future studies should extend these findings by employing larger sample sizes, by investigating specific task-based paradigms in these patients and by exploring the implications for treatment.

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Visually-induced patients present decreased functional connectivity of vestibular-related brain regions.

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Visually-induced dizziness patients present increased functional connectivity of visual and cerebellar brain regions.

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These findings might underlie typically seen symptoms in visually-induced dizziness, i.e. an overreliance on visual cues.

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This is the first exploratory study investigating the underlying neural aspects of visually-induced dizziness.

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These preliminary findings should be extended by larger sample sizes and by supplementing rsfMRI with task-based paradigms.

The Effect of Optokinetic Stimulation on Perceptual and Postural Symptoms in Visual Vestibular Mismatch Patients

Background

Vestibular patients occasionally report aggravation or triggering of their symptoms by visual stimuli, which is called visual vestibular mismatch (VVM). These patients therefore experience discomfort, disorientation, dizziness and postural unsteadiness.

Objective

Firstly, we aimed to get a better insight in the underlying mechanism of VVM by examining perceptual and postural symptoms. Secondly, we wanted to investigate whether roll-motion is a necessary trait to evoke these symptoms or whether a complex but stationary visual pattern equally provokes them.

Methods

Nine VVM patients and healthy matched control group were examined by exposing both groups to a stationary stimulus as well as an optokinetic stimulus rotating around the naso-occipital axis for a prolonged period of time. Subjective visual vertical (SVV) measurements, posturography and relevant questionnaires were assessed.

Results

No significant differences between both groups were found for SVV measurements. Patients always swayed more and reported more symptoms than healthy controls. Prolonged exposure to roll-motion caused in patients and controls an increase in postural sway and symptoms. However, only VVM patients reported significantly more symptoms after prolonged exposure to the optokinetic stimulus compared to scores after exposure to a stationary stimulus.

Conclusions

VVM patients differ from healthy controls in postural and subjective symptoms and motion is a crucial factor in provoking these symptoms. A possible explanation could be a central visual-vestibular integration deficit, which has implications for diagnostics and clinical rehabilitation purposes. Future research should focus on the underlying central mechanism of VVM and the effectiveness of optokinetic stimulation in resolving it.

Magnetic resonance brain imaging in patients with visual vertigo

INTRODUCTION

Patients with visual vertigo (VV) report dizziness provoked by moving visual surroundings. It has been suggested that these subjects develop a compensation strategy for a vestibulo-proprioceptive deficit and rely excessively on visual input. We have postulated that patients with VV might have brain abnormalities that interfere with appropriate processing of visual stimulation and performed a brain MRI study to verify this hypothesis.

MATERIALS AND METHODS

Patients with VV of more than 3 months duration were included. They were asked to complete the Situational Characteristic Questionnaire (SCQ) that scores for the symptoms of VV. Dizzy patients without VV served as controls. A brain MRI was performed with a Siemens 1.5 Tesla scanner in patients and controls.

RESULTS

Twenty-four patients with VV were included. Their mean SCQ score was 1.45 ± 0.9 (normal 0.16 ± 0.28). In 50% of patients, abnormalities in MRI imaging were found. Thirty-three percent of 27 controls demonstrated an abnormal brain MRI. The two groups were similar in respect to the prevalence of a localized hemispheric or posterior fossa lesion (P = 0.13), but VV patients had more unspecific white matter brain changes than controls (P = 0.009). Patients and controls did not differ in age and gender distribution (P = 0.9) or the history of a neurotological event preceding their symptoms (P = 0.3).

CONCLUSIONS

Our study suggests that multiple white matter lesions might contribute to occurrence of the phenomenon of VV. Future prospective large-scale studies by specific MR techniques are indicated to validate our preliminary findings and elucidate the pathological mechanism of VV.