Multisensory vestibular cortex activated by otolith stimulation (fMRI)

Neurologische und somatoforme Schwindelsyndrome

Schwindel ist eines der haufigsten Leitsymptome in der Allgemeinmedizin und nach dem Kopfschmerz das haufigste Leitsymptom in der Neurologie. Die verschiedenen Schwindelsyndrome sollten nach organischen und somatoformen Syndromen unterschieden werden. Leider werden somatoforme Schwindelerkrankungen oft nicht oder verspatet in die Differenzialdiagnose einbezogen, weshalb die Diagnose verzogert gestellt wird. Dies tragt zu der ohnehin schnellen Chronifizierung dieser Schwindelerkrankungen bei und fuhrt haufig zu einer enormen Beeintrachtigung der Lebensqualitat bis hin zur Fruhberentung der Patienten und zu hohen Krankenkassenkosten. Daher ist bei komplexen Schwindelerkrankungen eine fruhe in…

Revised Definition of Neuropathic Pain and Its Grading System: An Open Case Series Illustrating Its Use in Clinical Practice

The definition of neuropathic pain has recently been revised by an expert committee of the Neuropathic Pain Special Interest Group of the International Association for the Study of Pain (NeuPSIG) as "pain arising as direct consequence of a lesion or disease affecting the somatosensory system," and a grading system of "definite," "probable," and "possible" neuropathic pain has been introduced. This open case series of 5 outpatients (3 men, 2 women; mean age 48 +/- 12 years) demonstrates how the grading system can be applied, in combination with appropriate confirmatory testing, to diagnosis neuropathic conditions in clinical practice. The proposed grading system includes a dynamic algorithm …

Expectation of sensory stimulation modulates brain activation during visual motion stimulation.

The differential effects of visual hemifield motion stimulation during fixation of a stationary target were compared under two conditions: fixation straight ahead without any further instructions and fixation straight ahead with attention shifted to the "dark hemifield." Data from nine right-handed volunteers revealed that striate and extrastriate right hemispheric visual areas exhibited larger activations during left hemifield motion stimulation when attention was shifted to the right dark hemifield. Montreal Neurological Institute (MNI) coordinates (26, -98, -4) of the additional clusters activated in the latter condition corresponded best to the kinetic occipital region, which is known t…

Dominance for Vestibular Cortical Function in the Non-dominant Hemisphere

The aim of this (15)O-labelled H(2)O bolus positron emission tomography (PET) study was to analyse the hemispheric dominance of the vestibular cortical system. Therefore, the differential effects of caloric vestibular stimulation (right or left ear irrigation with warm water at 44 degrees C) on cortical and subcortical activation were studied in 12 right-handed and 12 left-handed healthy volunteers. Caloric irrigation induces a direction-specific sensation of rotation and nystagmus. Significant regional cerebral blood flow increases were found in a network within both hemispheres, including the superior frontal gyrus/sulcus, the precentral gyrus and the inferior parietal lobule with the sup…

Changes in cerebellar activation pattern during two successive sequences of saccades

The changes in the cerebellar activation pattern of two successive fMRI scanning runs were determined for visually guided to‐and‐fro saccades in 12 healthy volunteers familiar with the study paradigm. Group and single subject‐analyses revealed a constant activation of the paramedian cerebellar vermis (uvula, tonsils, tuber, folium/declive), which reflects constant ocular motor activity in both runs. A significant decrease in activation of the cerebellar hemispheres found in the second run is best explained by either a decrease in attention or the effects of motor optimization and learning. The significant, systematic changes of the cerebellar activation pattern in two successive runs were n…

Voxel-based morphometry depicts central compensation after vestibular neuritis.

Objective Patients who have had vestibular neuritis (VN) show a remarkable clinical improvement especially in gait and posture >6 months after disease onset. Methods Voxel-based morphometry was used to detect the VN-induced changes in gray and white matter by means of structural magnetic resonance imaging. Twenty-two patients were compared an average 2.5 years after onset of VN to a healthy sex-and age-matched control group. Results Our analysis revealed that all patients had signal intensity increases for gray matter in the medial vestibular nuclei and the right gracile nucleus and for white matter in the area of the pontine commissural vestibular fibers. A relative atrophy was observed in…

Neural correlates of hemispheric dominance and ipsilaterality within the vestibularsystem

Earlier functional imaging studies on the processing of vestibular information mainly focused on cortical activations due to stimulation of the horizontal semicircular canals in right-handers. Two factors were found to determine its processing in the temporo-parietal cortex: a dominance of the non-dominant hemisphere and an ipsilaterality of the neural pathways. In an investigation of the role of these factors in the vestibular otoliths, we used vestibular evoked myogenic potentials (VEMPs) in a fMRI study of monaural saccular-otolith stimulation. Our aim was to (1) analyze the hemispheric dominance for saccular-otolith information in healthy left-handers, (2) determine if there is a predom…

Treatment of Specific Types of Nystagmus

■ The function of the ocular motor system is to hold images stable on the fovea. The vestibular system and the vestibulo-ocular reflex (VOR) also play an important role in this function. The VOR connects the peripheral vestibular endorgans – the semicircular canals and otoliths – with their appropriate pair of eye muscles via a three-neuronal arc.

Insula and sensory insular cortex and somatosensory control in patients with insular stroke

Background In functional imaging studies, the insular cortex (IC) has been identified as an essential part of the processing of a whole spectrum of multimodal sensory input. However, there are no lesion studies including a sufficient number of patients, which would reinforce the functional imaging data obtained from healthy subjects. Such lesion studies should examine how damage to the IC affects sensory perception. We chose acute stroke patients with lesions affecting the IC in order to fill this gap. Methods A comprehensive sensory profiling by applying a quantitative sensory testing protocol was performed and a voxel-lesion behaviour mapping analysis in 24 patients with acute unilateral …

Vaskulärer Schwindel

Ischemia,hemorrhages, and other vascular disorders can result in various central or peripheral vestibular syndromes with vertigo, oculomotor/balance disturbances, and nausea. The vascular vertigo syndromes listed in Table 1 can however be brought about by other causes such as demyelitizing focuses in multiple sclerosis or space-occupying lesions, so that not only localization of the damaged structure but also the various etiologies are decisive for the choice of therapy. Occasionally, combined functional disturbances of the peripheral and central vestibular system appear, such as an infarction of the inferior anterior cerebellar artery, which supplies the labyrinth and parts of the brainste…

Effects of electrical stimulation in vestibular cortex areas in humans.

The case of a patient with focal epilepsy is reported who underwent presurgical evaluation by stereotactic intracranial electroencephalographic (EEG) recording. A subdural semi-grid electrode, consisting of three multi-channel strip electrodes, was implanted over the temporal lobe and temporo-occipital region; one multi-channel depth electrode was applied towards the posterior insular cortex. During electrical stimulation and EEG monitoring eye movements were recorded by 3-D video-oculography. Stimulation of the medial temporal gyrus induced blurring of vision and horizontal nystagmus. Stimulation of the superior temporal gyrus with low intensities also induced blurring of vision and a simi…

Who is at risk for ongoing dizziness and psychological strain after a vestibular disorder?

Patients with vestibular vertigo syndromes often suffer from anxiety and depression, whereas patients with psychiatric disorders often experience subjective unsteadiness, dizziness, or vertigo. Thus, it has been hypothesized that the vestibular system may be interlinked with the emotion processing systems. The aim of the current study was to evaluate this hypothesis by correlating vestibular and psychiatric symptoms with the course of the disease over 1 year. This interdisciplinary, prospective, longitudinal study included a total of 68 patients with acute vestibular vertigo syndromes. Four subgroups of patients with benign paroxysmal positioning vertigo (BPPV, n=19), acute vestibular neuri…

Eyes open and eyes closed as rest conditions: impact on brain activation patterns

The patterns of associated brain activations during eyes-open and eyes-closed states in complete darkness considerably differ in fMRI. An "interoceptive" state with the eyes closed is characterized by visual cortex activation, while an "exteroceptive" state with the eyes open is characterized by ocular motor system activity. The impact of the chosen rest condition (eyes open or eyes closed in complete darkness) on the pattern of brain activations during visual stimulation was evaluated in 14 healthy volunteers. During fixation or dim light room illumination, the activation of the visual cortex was larger with the eyes-open rest condition than with the eyes-closed rest condition; however, ac…

A Pathway in the Brainstem for Roll-Tilt of the Subjective Visual Vertical: Evidence from a Lesion–Behavior Mapping Study

The perceived subjective visual vertical (SVV) is an important sign of a vestibular otolith tone imbalance in the roll plane. Previous studies suggested that unilateral pontomedullary brainstem lesions cause ipsiversive roll-tilt of SVV, whereas pontomesencephalic lesions cause contraversive roll-tilts of SVV. However, previous data were of limited quality and lacked a statistical approach. We therefore tested roll-tilt of the SVV in 79 human patients with acute unilateral brainstem lesions due to stroke by applying modern statistical lesion–behavior mapping analysis. Roll-tilt of the SVV was verified to be a brainstem sign, and for the first time it was confirmed statistically that lesions…

Fixation suppression of optokinetic nystagmus modulates cortical visual-vestibular interaction.

Water activation positron emission tomography and statistical group analysis were used to evaluate differences in activation-deactivation patterns during small-field visual motion stimulation, eliciting rightward optokinetic nystagmus and its fixation suppression in 12 healthy volunteers. Bilateral patterns of activation in the visual cortex, including the motion-sensitive area MT/V5, and deactivations in an assembly of vestibular areas (posterior insula, thalamus, anterior cingulate gyrus) during optokinetic nystagmus was markedly diminished or totally absent during its fixation suppression. This finding agrees with the concept of a reciprocal inhibitory interaction between the visual-opto…

Distribution of HSV-1 in Human Geniculate and Vestibular Ganglia: Implications for Vestibular Neuritis

Vestibular dysfunction in major depression

Acute Vestibular Nucleus Lesion Affects Cortical Activation Pattern during Caloric Irrigation in PET

Cortical representation of saccular vestibular stimulation: VEMPs in fMRI

Short tone bursts trigger a vestibular evoked myogenic potential (VEMP), an inhibitory potential which reflects a component of the vestibulocollic reflex (VCR). These potentials arise as a result of activation of the sacculus and are expressed through the vestibulo-collic reflex (VCR). Up to now, the ascending projections of the sacculus are unknown in humans, only the representation of the semicircular canals or the entire vestibular nerve has been demonstrated. The aim of this study was to determine whether a sacculus stimulus that evoked VEMPs could activate vestibular cortical areas in fMRI. To determine this, we studied the differential effects of unilateral VEMP stimulation in 21 heal…

Anatomical correlates of ocular motor deficits in cerebellar lesions

Humans are able to stabilize the images of moving targets on the retina by means of smooth pursuit eye movements. After the pontine level, all smooth pursuit pathways pass through the cerebellum. Previous animal studies gave evidence that two specific lesion sites within the cerebellum cause smooth pursuit disorders: those of the flocculus/paraflocculus and the vermis including lobule VI, VII, the uvula and the deep cerebellar nuclei. To date, there have been only a few lesion studies in patients with smooth pursuit disorders that do not allow direct comparison with a control group. In the present study, new lesion mapping techniques determined which cerebellar structures were involved in p…

P25. Sensitivity of imaging and electrophysiological brainstem testing in the diagnosis of acute vertebrobasilar ischemia

Medial Vestibular Nucleus Lesions in Wallenberg's Syndrome Cause Decreased Activity of the Contralateral Vestibular Cortex

Three patients with the clinical diagnosis of Wallenberg's syndrome caused by acute unilateral ischemic infarctions, which included the vestibular nucleus in the medullary brain stem and afferent vestibular pathways, were examined by positron emission tomography (PET) during caloric vestibular stimulation. They all had typical signs of vestibular dysfunction such as transient rotatory vertigo with vomiting at the onset, ipsiversive body and ocular lateropulsion, and a complete ocular tilt reaction with tilts of the subjective visual vertical. Compared with healthy volunteers, who show activation in a network of temporoparietal vestibular areas within both hemispheres, especially in the post…

Insular strokes cause no vestibular deficits.

Background and Purpose— In previous imaging studies, the posterior insular cortex (IC) was identified as an essential part for vestibular otolith perception and considered as a core region of a human vestibular cortical network. However, it is still unknown whether lesions exclusively restricted to the posterior IC suffice to provoke signs of vestibular otolith dysfunction. Thus, present data aimed to test whether patients with lesions restricted to the IC showed vestibular otolith dysfunction. Methods— We studied 10 acute unilateral stroke patients with lesions restricted to the IC which were tested for signs of vestibular otolith dysfunction, such as tilts of subjective visual vertical, …

Imaging the visual autokinetic illusion with fMRI

During fixation of a stationary, dim light-emitting diode (LED) in complete darkness, a subtle, apparent motion is perceived which is called autokinesis. This autokinetic illusion increases with increasing fixation time. Eleven healthy subjects were examined by fMRI while fixating an LED in darkness for 35 s. BOLD signal changes of the first and the second half of the fixation period were compared. While the stimulus was the same for both periods, perception differed in that autokinesis was more pronounced in the second half. This second half of the period was associated with bilateral activations in the motion-sensitive middle occipito-temporal area known as MT/V5. Our finding suggests tha…

Nonlinear nystagmus processing causes torsional VOR nonlinearity.

The eye movement component that rotates around the line of sight, i.e., the ocular torsion, is in many aspects different from horizontal and vertical eye movements. While ocular torsion is mediated only by reflexive pathways like the torsional vestibulo-ocular and optokinetic reflexes (TVOR and OKN, respectively), horizontal and vertical components are also subject to intentional control mechanisms that are mediated by the saccadic and the pursuit systems. Dynamic properties of torsional eye movements are also very distinct. While horizontal and vertical VOR components show a gain close to unity and a small neural integration leakage with a time constant around pi=30 s, the TVOR shows a sma…

Topodiagnostic implications of hemiataxia: An MRI-based brainstem mapping analysis

The topodiagnostic implications of hemiataxia following lesions of the human brainstem are only incompletely understood. We performed a voxel-based statistical analysis of lesions documented on standardised MRI in 49 prospectively recruited patients with acute hemiataxia due to isolated unilateral brainstem infarction. For statistical analysis individual MRI lesions were normalised and imported in a three-dimensional voxel-based anatomical model of the human brainstem. Statistical analysis revealed hemiataxia to be associated with lesions of three distinct brainstem areas. The strongest correlation referred to ipsilateral rostral and dorsolateral medullary infarcts affecting the inferior ce…

Torsional eye movement responses to monaural and binaural galvanic vestibular stimulation: side-to-side asymmetries.

Vestibular stimulation by head accelerations always involves multisensory activation of the vestibular, somatosensory, and visual systems. Over the past few years, galvanic vestibular stimulation (GVS) has become increasingly popular for testing vestibular function for clinical and research purposes. Although GVS provides a nonphysiological stimulation, it is more selective than natural head accelerations and is thus an attractive tool for such tests. Eye movement responses elicited by GVS mainly consist of torsional and horizontal components, as first described by Hitzig in 1871. Animal experiments have shown that GVS increases the vestibular afferent spike frequency at the cathodal site a…

Inhibitory interhemispheric visuovisual interaction in motion perception.

Findings of an earlier functional magnetic resonance imaging (fMRI) study that coherent motion stimulation of the right or left visual hemifield exhibited negative signal changes (deactivations) in the primary visual cortex and the lateral geniculate nucleus contralateral to the stimulated hemisphere were evaluated to determine the functional significance of this contralateral inhibition of the visual system. Fourteen subjects participated in a psychophysical study on the perception of single object motion (0.4 degrees /s) in one visual hemifield with or without concurrent coherent motion stimulation of the contralateral hemifield. Mean detection times for horizontal object motion (0.5 +/- …

255 QUANTITATIVE SENSORY TESTING: ASSESSMENT OF THE NEUROPATHIC COMPONENT IN CANCER PAIN

Involvement of Jugular Valve Insufficiency in Cerebral Venous Air Embolism

Background. Cerebral venous air entrapment is a rare finding on cranial computed tomography (CT) scan. Peripheral air embolism is discussed as a potential cause. However, the mechanism of retrograde passage through internal jugular valves and veins is unclear. Case Report. The case of a patient is reported, who had air entrapment in the left cavernous sinus. Prior to CT scanning, a peripheral intravenous line had been placed. Ultrasound revealed excessive insufficiency of the left internal jugular valve. To further study the mechanism of embolism, an echo contrast agent was injected into the cubital vein. A Valsalva maneuver resulted in retrograde transition of microbubbles across the insuf…

3.7. Are signs of ocular tilt reaction in cerebellar lesions mediated by the dentate nucleus?

Standfest? Erste Ergebnisse der Entwicklung eines kognitiv-verhaltenstherapeutischen Gruppenschulungsprogramms zur Behandlung des somatoformen Schwindels

Anhand einer explorativen Fragestellung soll der Einfluss eines Schulungsprogramms fur somatoforme Schwindelpatienten auf dysfunktionale Krankheitsreprasentationen, Symptomstarke und psychische Komorbiditat uberpruft werden. Randomisiertes Wartekontrollgruppen-Design: 10 Patienten wurden der Kontrollgruppe zugewiesen; 14 Patienten der Interventionsgruppe durchliefen die Diagnostik im Pratest, Posttest und eine 3- bzw. 12-Monats-Katamnese. Die Fragebogenbatterie umfasste den Illness Perception Questionnaire, Vertigo Symptom Scale, Vertigo Handicap Questionnaire, Hospital Anxiety and Depression Scale und Physical Health Questionnaire. Hypothesenkonform verbesserte sich die personliche Kontrol…

Functional Magnetic Resonance Imaging Activations of Cortical Eye Fields during Saccades, Smooth Pursuit, and Optokinetic Nystagmus

Saccades, smooth pursuit, and optokinetic nystagmus (OKN) are three basic eye movements in our ocular motor repertoire that enable us to explore the visual field. These eye movements are cortically controlled in different cortical eye fields, including the frontal eye fields (FEF) and parietal eye fields (PEF), as well as the motion-sensitive visual area MT+/V5. It is not known if this cortical control is organized in parallel cortico-cortical networks or in adjacent subregions of one system. Nor do we know where the specific eye fields are exactly located. Functional magnetic resonance imaging (fMRI) was used to investigate these open questions about the FEF, PEF, and MT+/V5. Activations o…

Sympathetic activity at rest and motor brain areas: FDG-PET study.

Although recent studies identified brain areas which are involved in short term activation of the sympathetic nervous system, little is known about brain mechanisms which generate the individual variability of basal autonomic activity. In this fluorodeoxyglucose positron emission tomography study (FDG-PET), we aimed to identify brain regions, which covary with function parameters of the autonomic nervous system at rest. Therefore, FDG-PET (Siemens, Germany) was performed twice in 14 healthy resting subjects (7 m, 7 f; mean age 29.5 years) while different parameters of autonomic function were assessed simultaneously: Blood pressure, heart rate, power spectra of heart rate variability (HF/LF …

Antiamphiphysin-positive stiff-person syndrome associated with small cell lung cancer

The paraneoplastic amphiphysin(+) stiff-person syndrome (SPS) has so far only been described in women with breast adenocarcinoma. Here, we describe the rare case of a female patient with antiamphiphysin(+) SPS due to small cell cancer of the lung.

Topodiagnostic significance of hemiataxia: An MRI based mapping analysis

Quantitative sensory testing compared to conventional neurological diagnostics in patients with vibration induced vasospastic syndrome

Atypical Facial Pain

Publisher Summary This chapter discusses “atypical facial pain,” which was introduced originally to distinguish trigeminal neuralgia from other facial pain syndromes. The term “atypical facial pain” is also used mostly as a residual category for otherwise unclassifiable pain syndromes in the facial region. The International Headache Society defines atypical facial pain as a persistent facial pain that does not have the characteristics of the cranial neuralgias and is not associated with physical signs or demonstrable organic causes. It is present daily and persists for most or all of the day. It is confined at onset to a limited area on one side of the face and may spread to the upper and l…

Persistence of symptoms in primary somatoform vertigo and dizziness: a disorder "lost" in health care?

The aim of this study was to perform a 3-year follow-up of primary somatoform vertigo and dizziness (SVD) regarding health care use and treatment. Ninety-two patients with dizziness underwent detailed vestibular neurophysiological testing and a Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Psychometric assessments comprised the Vertigo Symptom Scale, the Vertigo Handicap Questionnaire, the SCL-90-R, and the Short-Form-36 Health Survey. At the 3-year follow-up, 65 patients with primary SVD (anxiety, n = 29; depression, n = 14; somatoform disorders, n = 22) were reassessed (70.7% response). The patients improved in symptom severity (p…

Chapter 4 3D brainstem topodiagnosis – a voxel-based model analyzing MR imaging data

Publisher Summary This chapter presents a new method of statistically based three-dimensional (3D) brainstem mapping to identify brainstem structures responsible for specific clinical and electrophysiological abnormalities. To ensure reliable correlations, a large cohort of patients with magnetic resonance (MR)-documented brainstem infarctions were recruited in two European neurological institutions—namely, the Department of Neurology, Johannes Gutenberg University, Mainz, Germany, and the Department of Neurological Sciences, “La Sapienza” University of Rome, Italy. This method minimizes the risk of highlighting vascular territories rather than the structures specifically responsible for th…

Functional Plasticity after Unilateral Vestibular Midbrain Infarction in Human Positron Emission Tomography.

The aim of the study was to uncover mechanisms of central compensation of vestibular function at brainstem, cerebellar, and cortical levels in patients with acute unilateral midbrain infarctions presenting with an acute vestibular tone imbalance. Eight out of 17 patients with unilateral midbrain infarctions were selected on the basis of signs of a vestibular tone imbalance, e.g., graviceptive (tilts of perceived verticality) and oculomotor dysfunction (skew deviation, ocular torsion) in F18-fluordeoxyglucose (FDG)-PET at two time points: A) in the acute stage, and B) after recovery 6 months later. Lesion-behavior mapping analyses with MRI verified the exact structural lesion sites. Group su…

Keeping memory clear and stable--the contribution of human basal ganglia and prefrontal cortex to working memory.

Successful remembering involves both hindering irrelevant information from entering working memory (WM) and actively maintaining relevant information online. Using a voxelwise lesion-behavior brain mapping approach in stroke patients, we observed that lesions of the left basal ganglia render WM susceptible to irrelevant information. Lesions of the right prefrontal cortex on the other hand make it difficult to keep more than a few items in WM. These findings support basal ganglia-prefrontal cortex models of WM whereby the basal ganglia play a gatekeeper role and allow only relevant information to enter prefrontal cortex where this information then is actively maintained in WM.

Thalamic infarctions cause side-specific suppression of vestibular cortex activations.

H2O15-PET was performed during caloric vestibular stimulation of the right and left external ears in eight right-handed patients with acute unilateral infarctions or haemorrhages of the posterolateral thalamus (four right, four left). The posterolateral thalamus is the relay station for ipsi- and contralateral ascending vestibular input to the multiple multisensory vestibular cortex areas. The aim of this study was to evaluate the differential effects of unilateral vestibular thalamic lesions on thalamo-cortical projections, right hemispheric dominance and reciprocal inhibitory visual-vestibular interaction, as well as perceptual and ocular motor consequences during caloric irrigation. The …

An educational multimedia campaign improves stroke knowledge and risk perception in different stroke risk groups.

Background and purpose:  Stroke risk factor knowledge and individual risk perception are low in the general public. Our study aimed at identifying the educational effects of a multimedia campaign on stroke knowledge and risk perception in several subgroups at increased risk of stroke. Methods:  Telephone surveys were administered in a random sample of 500 members of the general public, before and immediately after an intense 3 months educational campaign using various mass and print media. Results:  A total of 32.7% of respondents considered themselves as being at risk of stroke before, and 41.9% (P < 0.01) after the intervention. Evaluation of stroke risk increased with number of appreciat…

Ultrasound-induced blood clot dissolution without a thrombolytic drug is more effective with lower frequencies.

&lt;i&gt;Background and Purpose:&lt;/i&gt; Therapeutic ultrasound as stand-alone therapy or in combination with rt-PA has proven to be an effective measure for recanalisation of acute vessel occlusion in different in vitro and in vivo studies. Uncertainty still exists concerning the optimal frequency and intensity with regard to the thrombolytic efficacy of ultrasound. The purpose of this study was a direct comparison of different ultrasound frequencies, when otherwise using identical measurement settings and parameters. &lt;i&gt;Methods:&lt;/i&gt; Ultrasound-induced dissolution of fresh human blood clots was studied in a flow system using low-frequency continuous wave ultrasound of 20, 40 …

Brain Edema and Intracerebral Necrosis Caused by Transcranial Low-Frequency 20-kHz Ultrasound

Background and Purpose— Ultrasound-accelerated thrombolysis is a promising approach toward acute stroke treatment. In previous in vitro studies, we demonstrated enhanced thrombus destruction induced by 20-kHz ultrasound. However, little is known about biological interactions of low-frequency ultrasound with brain tissue. The aim of this in vivo MRI study was to assess safety aspects of transcranial low-frequency ultrasound in rats. Methods— The cranium of 33 male Wistar rats was sonificated for 20 minutes (20-kHz continuous wave). Power output was varied between 0 and 2.6 W/cm 2 . Tympanal and rectal temperature was monitored. Diffusion-weighted imaging and T2-weighted imaging was performe…

Diffusionsgewichtetes MRT bei vertebrobasil�ren Isch�mien

The aim of this study was to evaluate the applicability, sensitivity, and predictive power of diffusion-weighted MR imaging (DWI) in the diagnosis of vertebrobasilar infarction. From 1997 to 2002, we prospectively recruited 268 patients with acute signs and symptoms suspective of vertebrobasilar ischemia. The patients underwent biplanar EPI-T2 and EPI DWI within 24 h after onset of symptoms and high-resolution MRI as a control within 7 days. One hundred twenty-one patients had additional CT scanning. The DWI revealed acute vertebrobasilar infarction in 71.0%. The mean time exposure of DWI was 8 min and thus no more than that of CT imaging. It showed significantly more acute lesions than CT …

Functional correlate and delineated connectivity pattern of human motion aftereffect responses substantiate a subjacent visual-vestibular interaction.

The visual motion aftereffect (MAE) is the most prominent aftereffect in the visual system. Regarding its function, psychophysical studies suggest its function to be a form of sensory error correction, possibly also triggered by incongruent visual-vestibular stimulation. Several observational imaging experiments have deducted an essential role for region MT+ in the perception of a visual MAE but not provided conclusive evidence. Potential confounders with the MAE such as ocular motor performance, attention, and vection sensations have also never been controlled for. Aim of this neuroimaging study was to delineate the neural correlates of MAE and its subjacent functional connectivity pattern…

Dizziness: Anxiety, health care utilization and health behavior—

Background: Due to the lack of epidemiological data on the relation of dizziness and anxiety, we investigated the prevalence of dizziness and anxiety in a representative sample of the German population. We explored the consequences of comorbid anxiety for emotional distress, functional impairment, health care utilization, and health behavior in dizziness. Methods: By the end of 2006, we surveyed a total of 1287 persons between 14 and 90 years of age in their homes by trained interviewers with standardized self-rating questionnaires on anxiety (Patient Health Questionnaire, Generalized Anxiety Disorder Scale, Mini-Social Phobia Inventory) and dizziness (Vertigo Symptom Scale). The sample was…

Analysis of Internal Jugular Vein Insufficiency—A Comparison of Two Ultrasound Methods

Abstract Jugular venous valve insufficiency is a contributing factor to different pathologic conditions. For assessment of insufficiency, two ultrasound techniques have been developed, that are based on very different methodology (direct Doppler assessment versus air contrast ultrasound venography [ACUV]). This study was conducted to compare these two methods to improve comparability of existing studies and diagnostic accuracy in future studies. The function of 40 valves was determined in 20 individuals during a Valsalva maneuver. For direct Doppler assessment, valvular competence was assessed on basis of Doppler recordings, following recently established criteria. Valvular insufficiency in…

Sensory system interactions during simultaneous vestibular and visual stimulation in PET

The patterns of regional cerebral blood flow (rCBF) increases and decreases in PET were compared for unimodal vestibular, unimodal visual, and for simultaneous vestibular and visual stimulation. Thirteen healthy volunteers were exposed to a) caloric vestibular stimulation, b) small-field visual motion stimulation in roll, c) simultaneous caloric vestibular and visual pattern stimulation. Unimodal vestibular stimulation led to activations of vestibular cortex areas, in particular the parieto-insular vestibular cortex (PIVC), and concurrent deactivations of visual cortical areas [Brodmann area (BA) 17-19]. Unimodal visual motion stimulation led to activations of the striate visual cortex and …

Therapeutic Application of 20-kHz Transcranial Ultrasound in an Embolic Middle Cerebral Artery Occlusion Model in Rats

Background and Purpose— Therapeutic application of diagnostic ultrasound has been shown to improve recanalization rates in patients with acute cerebral vessel occlusion. There is experimental evidence that low-frequency ultrasound may be superior. This study was designed to evaluate the therapeutic efficacy and safety of low-frequency ultrasound in an embolic middle cerebral artery occlusion model in rats. A parameter setting was used that had not previously shown any side effects and interactions with healthy rat brain tissue. Methods— Male Wistar rats were submitted to middle cerebral artery clot embolism and transcranial treatment with 20-kHz continuous-wave ultrasound (0.2 W/cm 2 ), ei…

Psychiatric Disorders in Otoneurology Patients

Nearly half the patients who are in specialized otoneurologic units exhibit psychiatric disorders. The disorders are most significant in patients who have the chief symptoms of dizziness, complex forms of tinnitus, or sudden and relapsing sensorineural hearing loss. If not properly diagnosed, these disorders can lead to improper treatment, particularly when the illness is a somatoform otoneurologic disorder. Patients who have comorbid symptoms, such as reactive anxiety or depressive disorders, may experience difficulties in coping with the illness. In many instances, reactive psychologic disorders can lead to severe impairment of daily life and work activities.

Vestibular compensation of otolith graviceptive dysfunction in stroke patients

BACKGROUND AND PURPOSE A sensitive and frequent clinical sign of a vestibular tone imbalance is the tilt of the perceived subjective visual vertical (SVV). There are no data yet focusing on lesion location at the cortical level as a factor for predicting compensation from the tilt of the SVV. METHODS With modern voxelwise lesion behavior mapping analysis, the present study determines whether lesion location in 23 right-hemispheric cortical stroke patients with an otolith dysfunction could predict the compensation of a vestibular tone imbalance in the chronic stage. RESULTS Our statistical anatomical lesion analysis revealed that lesions of the posterior insular cortex are involved in vestib…

Modeling Vestibular Compensation: Neural Plasticity Upon Thalamic Lesion.

The present study in rats was conducted to identify brain regions affected by the interruption of vestibular transmission and to explore selected aspects of their functional connections. We analyzed, by positron emission tomography (PET), the regional cerebral glucose metabolism (rCGM) of cortical, and subcortical cerebral regions processing vestibular signals after an experimental lesion of the left laterodorsal thalamic nucleus, a relay station for vestibular input en route to the cortical circuitry. PET scans upon galvanic vestibular stimulation (GVS) were conducted in each animal prior to lesion and at post-lesion days (PLD) 1, 3, 7, and 20, and voxel-wise statistical analysis of rCGM a…

Evidence for cortical visual substitution of chronic bilateral vestibular failure (an fMRI study).

Bilateral vestibular failure (BVF) is a rare disorder of the labyrinth or the eighth cranial nerve which has various aetiologies. BVF patients suffer from unsteadiness of gait combined with blurred vision due to oscillopsia. Functional MRI (fMRI) in healthy subjects has shown that stimulation of the visual system induces an activation of the visual cortex and ocular motor areas bilaterally as well as simultaneous deactivations of multisensory vestibular cortex areas. Our question was whether the chronic absence of bilateral vestibular input (BVF) causes a plastic cortical reorganization of the above-described visual-vestibular interaction. We used fMRI to measure the differential effects of…

Vestibular thalamus: Two distinct graviceptive pathways.

Objective: To determine whether there are distinct thalamic regions statistically associated with either contraversive or ipsiversive disturbance of verticality perception measured by subjective visual vertical (SVV). Methods: We used modern statistical lesion behavior mapping on a sample of 37 stroke patients with isolated thalamic lesions to clarify which thalamic regions are involved in graviceptive otolith processing and whether there are distinct regions associated with contraversive or ipsiversive SVV deviation. Results: We found 2 distinct systems of graviceptive processing within the thalamus. Contraversive tilt of SVV was associated with lesions to the nuclei dorsomedialis, intrala…

A topodiagnostic investigation on body lateropulsion in medullary infarcts.

Body lateropulsion may occur without signs of vestibular dysfunction and vestibular nucleus involvement. The authors examined 10 such patients with three-dimensional brainstem mapping. Body lateropulsion without limb ataxia reflected an impairment of vestibulospinal postural control caused by a lesion of the descending lateral vestibulospinal tract, whereas body lateropulsion with limb ataxia was probably the consequence of impaired or absent proprioceptive information caused by a lesion of the ascending dorsal spino-cerebellar tract.

fMRI signal increases and decreases in cortical areas during small-field optokinetic stimulation and central fixation

Small-field optokinetic nystagmus (OKN) was performed in seven healthy volunteers in order to analyze the activation and deactivation patterns of visual motion, ocular motor, and multisensory vestibular cortex areas by means of fMRI during coherent visual motion stimulation. BOLD signal decreases (deactivations) were found in the first and second long insular gyri and retroinsular areas (the human homologue of the parietoinsular vestibular cortex and the visual posterior sylvian area in the monkey) of both hemispheres, extending into the transverse temporal gyrus and inferior-anterior parts of the superior temporal gyrus (BA 22), and the precentral gyri at two separate sites (BA 4 and 6). F…

15. Functional mapping of monaural auditory brainstem responses

Background and aims: The pedunculopontine nucleus (PPN) is a new deep brain stimulation (DBS) target, thought to be particularly for useful in ameliorating gait disturbance in Parkinson’s disease. Recent evidence shows a prominent theta (4–7 Hz) rhythm in the PPN (Tsang et al., Neurology, 2010; Simon et al., J. Neurophysiol., 2010; Shimamoto et al., JNNP, 2010). Given that theta activity is modulated by vestibular signals elsewhere in the brain, e.g. hippocampus, (Shin, Synapse, 2010; Chen et al., Neuroimage, 2010), we assessed whether vestibular signals modulate PPN theta activity. Methods: We recorded local field potentials (LFPs) in three patients with implanted bilateral subthalamic nuc…

FV 2. Modulation of the cortical vestibular network by means of rTMS and its neural correlate

Repetitive transcranial magnetic stimulation (rTMS) has been applied to sensory research and for the treatment of disorders in psychiatry and neurology since 1993 ( Wassermann and Zimmermann, 2012 ). The widespread cortical vestibular system, however, has to date not been targeted. Aim of our study was to manipulate vestibular regions in the human cortex by temporary virtual lesioning through rTMS and analyse the changes in the perception of a galvanic vestibular stimulation (GVS) as well as the differing activation patterns in functional neuroimaging. The effects of rectangular and sinusoidal bimastoidal GVS were studied in 16 healthy volunteers (8 F; mean age 23 years) in a 3T scanner. Da…

Rollvection versus linearvection: Comparison of brain activations in PET

We conducted a PET study to directly compare the differential effects of visual motion stimulation that induced either rollvection about the line of sight or forward linearvection along this axis in the same subjects. The main question was, whether the areas that respond to vection are identical or separate and distinct for rollvection and linearvection. Eleven healthy volunteers were exposed to large-field (100 degrees x 60 degrees ) visual motion stimulation consisting of (1) dots accelerating from a focus of expansion to the edge of the screen (forward linearvection) and (2) dots rotating counterclockwise in the frontal plane (clockwise rollvection). These two stimuli, which induced appa…

Veränderungen im Kortex nach peripher- und zentral-vestibulären Läsionen

In den letzten 10 Jahren konnten mit Hilfe der funktionellen Bildgebung des menschlichen Gehirns neue Erkenntnisse zum zentralen Gleichgewichtssystem zunachst bei Gesunden und jetzt auch bei Patienten mit umschriebenen vestibularen Lasionen erarbeitet werden. Basis fur diese Untersuchungen waren die Kenntnisse aus neurophysiologischen und Tracer-Studien an Tieren, insbesondere an Macacen, zum vestibularen System im Kortex aus den 70iger bis 90iger Jahren (Schwarz et al. 1973; Odkvist et al. 1974; Grusser et al. 1990a, b; Guldin und Grusser 1996). In diesen Studien konnten mehrere Areale im temporo-parietalen Kortex beschrieben werden, die alle multisensorisch waren, d.h. deren Neurone nicht…

Functional brain imaging of peripheral and central vestibular disorders.

This review summarizes our current knowledge of multisensory vestibular structures and their functions in humans. Most of it derives from brain activation studies with PET and fMRI conducted over the last decade. The patterns of activations and deactivations during caloric and galvanic vestibular stimulations in healthy subjects have been compared with those in patients with acute and chronic peripheral and central vestibular disorders. Major findings are the following: (1) In patients with vestibular neuritis the central vestibular system exhibits a spontaneous visual-vestibular activation–deactivation pattern similar to that described in healthy volunteers during unilateral vestibular sti…

Immunosuppressive treatment in bilateral vestibulopathy with inner ear antibodies.

Although vestibular recovery was observed after steroid treatment, it remains uncertain whether this improvement was spontaneous or due to medication. These data do not allow us to generally recommend corticosteroid treatment in patients with BVF and inner ear antibodies.A retrospective study was performed based on the observation of two patients with suspected autoimmune bilateral vestibular failure (BVF) with normal hearing and antilabyrinthine or nervous tissue-specific serum antibodies who showed vestibular recovery after corticosteroid treatment.Twelve patients with BVF and serum inner ear antibodies who had received imuunosuppressive treatment with corticosteroids were evaluated in te…

Performing allocentric visuospatial judgments with induced distortion of the egocentric reference frame: an fMRI study with clinical implications

The temporary improvement of visuospatial neglect during galvanic vestibular stimulation (Scand. J. Rehabil. Med. 31 (1999)117) may result from correction of the spatial reference frame distorted by the responsible lesion. Prior to an investigation of the neural basis of this effect in neurological patients, exploration of the neural mechanisms underlying such procedures in normals is required to provide insight into the physiological basis thereof. Despite their clinical impact, the neural mechanisms underlying the interaction of galvanic (and other) vestibular manipulations with visuospatial processing (and indeed the neural bases of how spatial reference frames are computed in man) remai…

Mathematical Model Predicts Clinical Ocular Motor Syndromes

: Clinical ocular motor syndromes were compared with ocular motor syndromes simulated by a mathematical model of the vestibuloocular reflex. The mathematical sensorimotor feedforward model of otolith control of three-dimensional binocular eye position is based on relevant anatomical connections of the vestibuloocular reflex from the utricles to extraocular eye muscles. This is the first attempt to simulate static ocular motor syndromes for unilateral utricular or vestibular nerve failure, lesions of the vestibular nucleus, and lesions of the ascending vestibuloocular reflex pathways. Comparison of the predicted syndromes with those found in patients with unilateral disorders of the vestibul…

Postlumbar Puncture Headache Syndrome

Publisher Summary This chapter presents a study on acute and chronic pain related to postlumbar puncture headache syndrome. The symptoms of the postlumbar puncture headache (PLPH) syndrome are positional, beginning in the upright posture and subsiding or improving when the patient reclines. Sometimes symptoms of PLPH occur spontaneously without a detectable dural defect. In these instances, suggested causes include a hyperactive resorption of cerebrospinal fluid (CSF) or a spontaneous mechanical dural hole. Magnetic resonance imaging (MRI) scans in patients with intracranial hypotension—either after LP or spontaneously—show meningeal enhancement, subdural effusions, and downward brain displ…

Hyperhidrosis

Sweating is a physiological and vital process. The basic distinction is made between two types of sweating: thermoregulatory and emotional sweating. Most of the sweat glands are of the eccrine type. They produce a thin secretion that is hypotonic to plasma (e1). Eccrine sweat glands are distributed all over the body; their highest density is in the axillary region, on the palms of the hands, and on the soles of the feet (1). Their main function is thermoregulation. Apocrine sweat glands are found primarily in the axillae and the urogenital region. These scent glands become active during puberty and secrete a viscous fluid. They are responsible for a person’s "personal," occasionally unpleas…

Incidence and anatomy of gaze-evoked nystagmus in patients with cerebellar lesions.

Background: Disorders of gaze-holding—organized by a neural network located in the brainstem or the cerebellum—may lead to nystagmus. Based on previous animal studies it was concluded that one key player of the cerebellar part of this gaze-holding neural network is the flocculus. Up to now, in humans there are no systematic studies in patients with cerebellar lesions examining one of the most common forms of nystagmus: gaze-evoked nystagmus (GEN). The aim of our present study was to clarify which cerebellar structures are involved in the generation of GEN. Methods: Twenty-one patients with acute unilateral cerebellar stroke were analyzed by means of modern MRI-based voxel-wise lesion-behavi…

Why Do Subjective Vertigo and Dizziness Persist over One Year after a Vestibular Vertigo Syndrome?

The overlap and interlinkage of dizzy symptoms in patients with psychiatric and vestibular vertigo/dizziness disorders is the subject of an ongoing debate. In a one-year follow up in 68 patients with vestibular vertigo syndromes, the persistency of vertigo and dizziness symptoms was examined and correlated with vestibular parameters and results from a psychiatric evaluation. Patients with vestibular migraine showed poorest improvement of vertigo and dizziness symptoms over time. In addition, patients who developed anxiety or depressive disorder after the onset of the vestibular disorder showed poor improvement and high persistency of symptoms.

Anosognosia for hemiparesis after left-sided stroke

In patients with left-sided lesions, anosognosia for hemiparesis (AHP) seems to be a rare phenomenon. It has been discussed whether this rareness might be due to an inevitable bias due to language dysfunction and whether the left hemisphere's role for our self-awareness of motor actions thus is underestimated. By applying functional magnetic resonance imaging (fMRI) we examined whether patients with AHP following a left hemisphere stroke show a regular, left-sided or a reversed, right-sided lateralization of language functions. Only the former observation would argue for an original role of the left hemisphere in self-awareness about limb function. In a consecutive series of 44 acute left-s…

Easy, Inexpensive, and Effective: Vestibular Exercises for Balance Control

The convincing study by Yardley and colleagues in this issue broadens our knowledge of treating dizziness and provides strong arguments to get our patients up and exercising.

200 TEST/RETEST- AND INTEROBSERVER-RELIABILITIY IN QUANTITATIVE SENSORY TESTING ACCORDING TO THE PROTOCOL OF THE GERMAN NETWORK ON NEUROPATHIC PAIN (DFNS)

Evidence for modulation of opioidergic activity in central vestibular processing: A [(18)F] diprenorphine PET study.

Animal and functional imaging studies had identified cortical structures such as the parieto‐insular vestibular cortex, the retro‐insular cortex, or the anterior cingulate cortex belonging to a vestibular cortical network. Basic animal studies revealed that endorphins might be important transmitters involved in cerebral vestibular processing. The aim of the present study was therefore to analyse whether the opioid system is involved in vestibular neurotransmission of humans or not. Changes in opioid receptor availability during caloric air stimulation of the right ear were studied with [(18)F] Fluoroethyl‐diprenorphine ([(18)F]FEDPN) PET scans in 10 right‐handed healthy volunteers and compa…

Vestibular compensation in cerebellar stroke patients.

Background and purpose There is little evidence about the site where compensatory vestibular mechanisms in patients with cerebellar strokes take place. Methods To determine whether the location of a cerebellar lesion might be a crucial variable in vestibular compensation a sample of 22 patients with cerebellar stroke were tested for graviceptive function in the acute and chronic stage. Results Our statistical anatomical lesion analysis indicated that mainly lesions of the cerebellar hemispheres (lobule V, VI, VIIa) hinder vestibular compensation and might lead to an overcompensation. Conclusions Overcompensation-induced dysfunction can be explained by the absence of cerebellar inhibitory si…

Posterior insular cortex - a site of vestibular-somatosensory interaction?

Background In previous imaging studies the insular cortex (IC) has been identified as an essential part of the processing of a wide spectrum of perception and sensorimotor integration. Yet, there are no systematic lesion studies in a sufficient number of patients examining whether processing of vestibular and the interaction of somatosensory and vestibular signals take place in the IC. Methods We investigated acute stroke patients with lesions affecting the IC in order to fill this gap. In detail, we explored signs of a vestibular tone imbalance such as the deviation of the subjective visual vertical (SVV). We applied voxel-lesion behaviour mapping analysis in 27 patients with acute unilate…

Interaction of somatoform and vestibular disorders

The high coincidence of organic vestibular and somatoform vertigo syndromes has appeared to support pathogenic models showing a strong linkage between them. It was hypothesised that a persisting vestibular dysfunction causes the development of anxiety disorders.To determine the relation between vestibular deficits and somatoform vertigo disorders in an interdisciplinary prospective study.Participants were divided into eight diagnostic groups: healthy volunteers (n=26) and patients with benign paroxysmal positioning vertigo (BPPV, n=11), vestibular neuritis (n=11), Menière's disease (n=7), vestibular migraine (n=15), anxiety (n=23), depression (n=12), or somatoform disorders (n=22). Neuro-ot…

Ageing‐related changes in the cortical processing of otolith information in humans

Acoustic short tone bursts (STB) trigger ocular and cervical vestibular-evoked myogenic potentials (oVEMPs/cVEMPs) by activating irregular otolith afferents. Simultaneously, STBs introduce an artificial net acceleration signal of otolith origin into the vestibular network. VEMP parameters as diagnostic otolith processing markers have been shown to decline after the age of thirty. To delineate the differential effects of healthy ageing on the cortical vestibular subnetwork processing otolith information, we measured cVEMPs and the differential effects of unilateral STB in three age groups (20-40, 40-60 and 60+; n = 42) using functional neuroimaging. STB evoked responses in the main vestibula…

Preserved visual-vestibular interaction in patients with bilateral vestibular failure

Background: During caloric vestibular stimulation, subjects showed bilateral activation of the vestibular cortex in the posterior insula and retroinsular region as well as concurrent deactivation of visual cortex areas bilaterally. This finding was the basis for the concept of a reciprocal inhibitory interaction between the vestibular and the visual systems. Objective: To analyze the modulations of this activation and deactivation pattern in patients with loss of vestibular input, that is, in patients with bilateral vestibular failure (BVF). Methods: Modulations of regional cerebral blood flow (rCBF) in PET were measured in nine patients with BVF and compared with those in healthy volunteer…

Lesions to the posterior insular cortex cause dysarthria

Background:  Up to now, there are few systematic studies in a sufficient number of patients with lesions involving the insular cortex (IC) examining whether damage of the IC is directly related to dysarthria. Thus, this is the first study applying modern voxel-lesion behaviour mapping (VLBM) aimed to examine whether the IC is involved in dysarthria – and if so – which part of the IC is involved. Methods:  Twenty-five patients with acute stroke lesions affecting the IC and peri-insular region were investigated employing VLBM analysis. Results:  Present data indicated that dysarthria is associated with stroke lesions affecting the right- and left-sided posterior IC. Conclusions:  Owing to the…

Vestibular Disorders. A Case Study Approach 2nd Edition. J.M. Furman, S.P. Cass (Eds.). Oxford University Press, 2003. ISBN 0-19-514579-8

3.5. Saccular activations in the brainstem and the cerebellum (fMRI)

Are signs of ocular tilt reaction in patients with cerebellar lesions mediated by the dentate nucleus?

A sensitive clinical sign of a vestibular tone imbalance in the roll plane is the ocular tilt reaction (OTR), a combination of skew deviation, ocular torsion and head and perceptual tilts such as tilts of the subjective visual vertical (SVV). Of these OTR components tilts of SVV are the most frequent. While these signs are regularly seen in patients with unilateral brainstem lesions, only a few case studies are available on their occurrence in patients with cerebellar lesions. Thus, the question arises whether cerebellar structures may be involved in contra- and/or ipsiversive tilts of the perceived vertical and other signs of OTR. We used lesion-mapping techniques in a total of 31 patients…

Vestibular-evoked myogenic potentials in "vestibular migraine" and Menière's disease: a sign of an electrophysiological link?

Characterizations of the signs and symptoms of "vestibular migraine" and of Meniere's disease seem to overlap, suggesting that both diseases might be due to a common peripheral vestibular dysfunction. Thus, the aim of the present study was to assess vestibular-evoked myogenic potentials (VEMPs) in both disorders to determine whether there might be an electrophysiological link between the two disorders. The amplitude and latency of VEMPs were measured from the sternocleidomastoid muscle in 63 patients with vestibular migraine (median age 47 years, range 24-70 years) and in 16 patients with Meniere's disease (median age 52 years, range 36-72 years), and compared with those of 63 sex- and age-…

Functional MRI of galvanic vestibular stimulation with alternating currents at different frequencies.

Abstract Functional MRI was performed in 28 healthy volunteers to study the effects of galvanic vestibular stimulation with alternating currents (AC-GVS) of different frequencies on brain activation patterns. The aims of this study were (1) to identify specific areas within the vestibular cortical network that are involved in the processing of frequency-specific aspects by correlation analyses, (2) to determine the optimal frequency for stimulation of the vestibular system with respect to perception, and (3) to analyze whether different frequencies of AC-GVS are mediated in different cortical areas or different sites within the vestibular cortex. AC-GVS was performed using sinusoidal stimul…

Improved Postural Control after Behavioural Short Term Intervention in Patients with Psychiatric Dizziness

Background:Patients with psychiatric dizziness often report subjective instability of stance and gait and fear of falls. They showed increased activity of their body sway in static posturography compared to normals (1, 2). Aim of the present study was to evaluate the efficiency of a behavioural therapy by static posturography.Methods:14 patients with psychiatric dizziness were included in the prospective study on static posturography to quantify the postural sway (sway path) during upright stance under different conditions. the psychosomatic examination comprised of standardized interviews (SCID-Interview) and a psychometric examination battery (SCL-90, VSS, VHQ). Results of static posturog…

Ocular tilt reaction: a clinical sign of cerebellar infarctions?

Ocular tilt reaction (OTR) consists of head tilt, ocular torsion (OT), and skew deviation (SKD) combined with perceptual tilts such as deviations of the subjective visual vertical (SVV). Few case reports have shown that OTR also occurs in patients with cerebellar infarctions.1–4 However, no systematic clinical studies are available on the frequency of signs of OTR in patients with cerebellar lesions. Therefore, the questions arose as to whether OTR is a common clinical sign of an acute cerebellar lesion and whether the time course of its components is similar to those from brainstem infarctions. The cerebellar structures involved in 31 patients were studied in detail elsewhere.5 ### Methods…

Deutschsprachige Validierung des Vertigo Handicap Questionnaire (VHQ) anhand einer Patientenstichprobe mit vestibulärem und somatoformem Schwindel

The Vertigo Handicap Questionnaire (VHQ) by Yardley (1992) assesses physical and psychosocial impairments of vertigo or dizziness. Our study examines the structure, reliability, and aspects of validity of the German version of the VHQ. 98 vestibular vertigo syndromes vs. 90 patients with somatoform vertigo and dizziness were evaluated with the VHQ, symptom severity (VSS), distress (GSI), anxiety and depression (HADS), catastrophizing beliefs (ACQ), fear of body sensations (BSQ), and quality of life (SF-36). For diagnostic classification detailed clinical neurological, neuro-otological and psychosomatic testing were conducted. Principal components analysis identified two factors, which could…

Three Determinants of Vestibular Hemispheric Dominance during Caloric Stimulation: A Positron Emission Tomography Study

1.2. 3-D brainstem mapping

MRI and neurophysiology in vestibular paroxysmia: contradiction and correlation

Background Vestibular paroxysmia (VP) is defined as neurovascular compression (NVC) syndrome of the eighth cranial nerve (N.VIII). The aim was to assess the sensitivity and specificity of MRI and the significance of audiovestibular testing in the diagnosis of VP. Methods 20 VP patients and, for control, 20 subjects with trigeminal neuralgia (TN) were included and underwent MRI (constructive interference in steady-state, time-of-flight MR angiography) for detection of a NVC between N.VIII and vessels. All VP patients received detailed audiovestibular testing. Results A NVC of N.VIII could be detected in all VP patients rendering a sensitivity of 100% and a specificity of 65% for the diagnosi…

Different short-term modulation of cortical motor output to distal and proximal upper-limb muscles during painful sensory nerve stimulation

The pattern of upper-limb muscle activation following painful stimulation has not been clarified in detail. We investigated the short-term inhibitory and excitatory effects of painful electrical digital stimulation on the motoneuron pools of distal and proximal upper-limb muscles. Transcranial magnetic stimulation (TMS) was used as test stimulus, and painful digital nerve stimulation as conditioning stimulus for motor evoked potential (MEP) recordings over the abductor digiti minimi (ADM), abductor pollicis brevis (APB), biceps brachii (BB), and deltoid muscles. Inhibition of the conditioned MEP response was most prominent in the distal muscles, whereas BB and deltoid muscles were only weak…

Visual-motion suppression in congenital pendular nystagmus.

Patients with a congenital pendular nystagmus are known not to experience oscillopsia in a normal visual environment. The data of a 31-year-old female patient suffering from a congenital pendular nystagmus are presented. The aim of the fluorodeoxyglucose positron emission tomography (FDG-PET) experiment was to analyze the regional cerebral glucose metabolism (rCGM) during minimal as well as maximal nystagmus. Video-oculography showed a maximum in frequency of the horizontal pendular nystagmus during gaze to the left, whereas the zone of minimal nystagmus was 10 degrees to the right. Two sessions with an 18F-fluorodeoxyglucose tracer were performed to analyze cerebral blood-glucose utilizati…

Interoceptive and multimodal functions of the operculo-insular cortex: tactile, nociceptive and vestibular representations.

The operculo-insular cortex has been termed the 'homeostatic control center' or 'general magnitude estimator' of the human mind. In this study, somatosensory, nociceptive and caloric vestibular stimuli were applied to reveal, whether there are mainly common, or possibly specific regions activated by one modality alone and whether lateralization effects, time pattern differences or influences of the aversive nature of the stimuli could be observed. Activation of the dorsal posterior insula was caused by all stimuli alike thus terming this area multimodal. Early phases of the noxious heat and caloric vestibular stimulation led to responses in the anterior insula. Using conjunction analyses we…

Asymmetric modulation of human visual cortex activity during 10 degrees lateral gaze (fMRI study).

We used BOLD fMRI to study the differential effects of the direction of gaze on the visual and the ocular motor systems. Fixation of a target straight ahead was compared to fixation of a target 10 degrees to the right and 10 degrees to the left from gaze straight ahead, and to eyes open in complete darkness in thirteen healthy volunteers. While retinotopic coordinates remained the same in all fixation conditions, the fixation target shifted with respect to a head-centered frame of reference. During lateral fixation, deactivations in higher-order visual areas (one ventral cluster in the lingual and fusiform gyri and one dorsal cluster in the postero-superior cuneus) and, as a trend, activati…

Cerebral embolic ischemia in rats: correlation of stroke severity and functional deficit as important outcome parameter.

The embolic MCA occlusion model in rats is used for recanalisation studies in acute stroke. In addition to the determination of lesion size, the assessment of functional outcome may improve the value of this model. Male Wistar rats were submitted to MCA clot embolism or sham surgery. In order to achieve a larger variety of lesion volume, 2 subgroups (each 7 animals) were subjected to differently sized emboli (30 and 40 mm). Follow-up period was 6 days. Outcome assessment consisted of a test battery including parallel bar crossing, observation of behaviour in an open field and an 8-arm maze and a neurological score with ten different sensorimotor and coordinative items. Animals were perfusio…

Neural correlates of disturbed perception of verticality.

Objective: Perception of verticality can be perturbed after cortical stroke. However, a relationship between lesion location and pathologic perception of verticality is still a matter of debate since previous studies revealed contradictory results. Thus, the aim of the current study was to test whether specific cortical lesions were associated with tilts of subjective visual vertical (SVV) and to determine the critical brain areas that cause such tilts in the case of a lesion. Methods: SVV was systematically studied in 54 patients (22 patients with left-sided and 32 patients with right-sided lesions) with acute unilateral strokes, analyzed by modern voxel-wise lesion-behavior mapping techni…

Somatotopic organization of the corticospinal tract in the human brainstem: a MRI-based mapping analysis.

To investigate the incompletely understood somatotopical organization of the corticospinal tract in the human brainstem, we performed a voxel-based statistical analysis of standardized magnetic resonance scans of 41 prospectively recruited patients with pyramidal tract dysfunction caused by acute brainstem infarction. Motor hemiparesis was rated clinically and by the investigation of motor evoked potentials to arms and legs. Infarction affected the pons in 85% of cases. We found the greatest level of significance of affected brainstem areas between the pontomesencephalic junction and the mid pons. Lesion location was significantly more dorsal in patients with hemiparesis affecting more prox…

H�ufigste Schwindelform im mittleren Alter: phobischer Schwankschwindel

Bislang liegen nur wenige valide epidemiologische Untersuchungen zum Leitsymptom Schwindel vor. Nach einer Analyse von 4214 Patienten einer uberregionalen Spezialambulanz fur Schwindel zwischen 1989 und 2002 stellen der benigne periphere paroxysmale Lagerungsschwindel (BPPV) und der phobische Schwankschwindel (PPV) die beiden haufigsten Schwindelsyndrome dar. In der vorliegenden Untersuchung wurde die relative Alters- und Geschlechtsverteilung dieser beiden Erkrankungen analysiert. Im Alter zwischen 20 und 50 Jahren stellt der PPV mit einem Anteil von 22–26% die relativ haufigste Schwindelform dar. Da der PPV einerseits unbehandelt meist chronifiziert und zu deutlichen (auch beruflichen) Be…

Metabolic changes in vestibular and visual cortices in acute vestibular neuritis

Five right-handed patients with a right-sided vestibular neuritis were examined twice with fluorodeoxyglucose positron emission tomography while lying supine with eyes closed: once during the acute stage (mean, 6.6 days) and then 3 months later when central vestibular compensation had occurred. Regional cerebral glucose metabolism (rCGM) was significantly increased (p <0.001 uncorrected) during the acute stage in multisensory vestibular cortical and subcortical areas (parietoinsular vestibular cortex in the posterior insula, posterolateral thalamus, anterior cingulate gyrus [Brodmann area 32/24], pontomesencephalic brainstem, hippocampus). Simultaneously, there was a significant rCGM decrea…

Functional brain imaging: a window into the visuo-vestibular systems

Advances have been made in identifying how areas involved in processing vestibular, ocular motor, and visual information are represented in the human cortex as well as the cortical interaction between these systems in healthy subjects.While we know how some vestibular and ocular motor disorders modify visuo-vestibular interaction by changing the 'normal' cortical activation-deactivation patterns, it is still early days in functional magnetic resonance imaging studies of patients with specific disorders. Findings from current brain imaging studies of several vestibular, ocular motor, and cerebellar disorders are presented.The promise of more insights into the complex neuronal networks of the…

3.2. Brain stem and cerebellar activation during optokinetic stimulation

Direction‐dependent visual cortex activation during horizontal optokinetic stimulation (fMRI study)

Looking at a moving pattern induces optokinetic nystagmus (OKN) and activates an assembly of cortical areas in the visual cortex, including lateral occipitotemporal (motion‐sensitive area MT/V5) and adjacent occipitoparietal areas as well as ocular motor areas such as the prefrontal cortex, frontal, supplementary, and parietal eye fields. The aim of this functional MRI (fMRI) study was to investigate (1) whether stimulus direction‐dependent effects can be found, especially in the cortical eye fields, and (2) whether there is a hemispheric dominance of ocular motor areas. In a group of 15 healthy subjects, OKN in rightward and leftward directions was visually elicited and statistically compa…

The topographic diagnosis of acquired nystagmus in brainstem disorders.

Evidence is presented for a clinical classification of central vestibular syndromes according to the three major planes of action of the vestibulo-ocular reflex (VOR): yaw, pitch, and roll. The plane-specific vestibular syndromes are determined by ocular motor, postural, and perceptual signs. Yaw plane signs are horizontal nystagmus, horizontal past pointing, rotational and lateral body falls to the right or to the left, and horizontal deviation of perceived straight-ahead. Pitch plane signs are upbeat/downbeat nystagmus, forward/backward tilts and falls, and upward or downward deviations of the perceived horizontal. Roll plane signs are torsional nystagmus, skew deviation, ocular torsion, …

The role of the thalamus in the human subcortical vestibular system1

Most of our knowledge concerning central vestibular pathways is derived from animal studies while evidence of the functional importance and localization of these pathways in humans is less well defined. The termination of these pathways at the thalamic level in humans is even less known. In this review we summarize the findings concerning the central subcortical vestibular pathways in humans and the role of these structures in the central vestibular system with regard to anatomical localization and function. Also, we review the role of the thalamus in the pathogenesis of higher order sensory deficits such as spatial neglect, pusher syndrome or thalamic astasia and the correlation of these p…

Anatomisches Korrelat der vertikalen Otolithenwahrnehmung: Topodiagnostische Erkenntnisse vom Hirnstamm bis zum Kortex

Die intakte vertikale Wahrnehmung ist eine wichtige Voraussetzung fur unsere Fahigkeit des aufrechten Gehens. Diese Fahigkeit ist multisensorisch, wobei der Signalverarbeitung der Otolithen eine dominante Rolle zukommt. Moderne Lasionsmethoden und funktionelle Bildgebungsdaten konnten zeigen, dass sowohl Strukturen im Kleinhirn, Hirnstamm und Thalamus als auch supratentorielle Regionen wie der insulare Kortex – Strukturen eines vestibularen Netzwerks – an der vestibular dominierten vertikalen Wahrnehmung beteiligt sind. Dieser Ubersichtsartikel beschreibt unseren aktuellen Kenntnisstand uber die anatomischen Regionen und Mechanismen, die eine intakte vestibulare vertikale Wahrnehmung beding…

Anatomical correlate of positive spontaneous visual phenomena: a voxelwise lesion study.

Objectives: Visual phenomena such as phosphenes, photopsias, or complex visual hallucinations occur in patients with lesions affecting the occipital, parietal, or temporal lobe. Whether these phenomena are provoked by lesions in specific anatomical regions is still uncertain. To determine which brain regions might be involved in such visual phenomena, we used new brain imaging and lesion analysis tools that allow a direct comparison with control patients. Methods: Visual phenomena were investigated in a total of 23 patients with acute infarctions along the visual pathways (6 patients with left-sided and 17 patients with right-sided lesions). Results: Ten of these 23 patients (43%) reported …

Anatomical Correlate of Impaired Covert Visual Attentional Processes in Patients with Cerebellar Lesions

In the past years, claims of cognitive and attentional function of the cerebellum have first been raised but were later refuted. One reason for this controversy might be that attentional deficits only occur when specific cerebellar structures are affected. To further elucidate this matter and to determine which cerebellar regions might be involved in deficits of covert visual attention, we used new brain imaging tools of lesion mapping that allow a direct comparison with control patients. A total of 26 patients with unilateral right-sided cerebellar infarcts were tested on a covert visual attention task. Eight (31%) patients showed markedly slowed responses, especially in trials in which an…

The importance of the insular cortex for vestibular and spatial syndromes.

BACKGROUND AND PURPOSE The aim of the study was to identify the neuroanatomical correlates and associations of neuropsychological syndromes after acute unilateral right-hemisphere brain lesions. The neuropsychological syndromes considered were orientation in three-dimensional space such as tilts of the subjective visual vertical or of the subjective haptic vertical, pusher syndrome, visual neglect and unawareness of paresis (anosognosia for hemiparesis). These neuropsychological phenomena have been found to occur separately or in different combinations after lesions to the right insular cortex. METHOD Magnetic resonance imaging scans were obtained from 82 patients with acute right-hemispher…

P24. Classical brain stem syndromes: Myth or reality?

Left-hemispheric dominance for articulation: a prospective study on acute ischaemic dysarthria at different localizations.

Dysarthria is a frequent symptom in cerebral ischaemia. However, speech characteristics of these patients have not previously been investigated in relation to lesion site in a prospective study. We investigated the auditory perceptual features in 62 consecutive patients with dysarthria due to a single, non-space-occupying cerebral infarction confirmed by MRI. Standardized speech samples of all patients were stored within 72 h after stroke onset using a digital tape recorder. Speech samples were assessed independently by two experienced speech therapists, who were unaware of the clinical and neuroradiological findings, using an interval scale ranging from 0 to 6. Separately assessed were fea…

P13. Compensation processes for central vestibular dysfunction in patients with acute medullary infarctions (FDG-PET study)

251 SENSORY PROFILES IN PAINFUL VS. NON-PAINFUL CHEMOTHERAPY-INDUCED POLYNEUROPATHY

18F-fluorodeoxyglucose hypometabolism in cerebellar tonsil and flocculus in downbeat nystagmus.

A patient with downbeat nystagmus was examined by F-fluorodeoxyglucose-positron emission tomography once while off and twice while on successful treatment with 4-aminopyridine. All positron emission tomography scans of the patient showed a reduced cerebral glucose metabolism bilaterally in the region of the cerebellar tonsil and flocculus/paraflocculus when compared with a normal database of the whole brain. An additional region-of-interest analysis revealed that 4-aminopyridine treatment lessened the hypometabolism. This finding supports the hypothesis that the cerebellar tonsil and (para-) flocculus play a crucial role in downbeat nystagmus. The hypometabolism might reflect reduced inhibi…

Zentrale vestibuläre Schwindelformen

Zentrale vestibulare Schwindelformen entstehen durch Lasionen entlang der vestibularen Verbindungen von den Vestibulariskernen in der Medulla oblongata zu den okulomotorischen Kernen und Integrationszentren im rostralen Mittelhirn sowie zum Vestibulozerebellum, Thalamus und vestibularen Kortex im temporoparietalen Groshirn (Brandt und Dieterich 1995). Es handelt sich oft um klar definierte klinische Syndrome unterschiedlicher Atiologie, deren typische Befunde aus Okulomotorik, Wahrnehmung und Haltungsregulation eine topische Hirnstammdiagnostik erlauben. Die Analyse des Nystagmus kann fur die lokalisatorische Zuordnung hilfreich sein (Buttner et al. 1995). Auf diese typischen Befunde soll h…

Eye closure in darkness animates sensory systems.

Single subject and group analyses (n = 12) showed that the eyes-open and eyes-closed states in complete darkness considerably and consistently differ in the patterns of associated brain activation in fMRI. During nonchanging external stimulation, ocular motor and attentional systems were activated when the eyes were open; the visual, somatosensory, vestibular, and auditory systems were activated when the eyes were closed. These data suggest that there are two different states of mental activity: with the eyes closed, an "interoceptive" state characterized by imagination and multisensory activity and with the eyes open, an "exteroceptive" state characterized by attention and ocular motor act…