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Vestibular Neuronitis  

Science.gov (United States)

... Meniere Disease Herpes Zoster Oticus Vestibular Neuronitis Purulent Labyrinthitis Ear Disorders Caused by Drugs Acoustic Neuroma Merck ... to Top Previous: Herpes Zoster Oticus Next: Purulent Labyrinthitis Audio Figures Photographs Pronunciations Sidebar Tables Videos Copyright © ...

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Vestibular neuronal function of cats following unilateral vertebral artery occlusion.  

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Since vertigo is known to be caused by vertebrobasilar arterial occlusive disease (ex. vertebrobasilar insufficiency; VBI), an electrophysiological study was performed to examine the effects of a unilateral vertebral artery (VA) occlusion on the neuronal activities of the medial vestibular nucleus (MVN) and vestibular ganglion (VG) in alpha-chloralose-anesthetized cats. Single neuronal activity in the MVN and VG was recorded extracellularly with a glass-insulated silver wire microelectrode. When the unilateral VA was occluded for 5 min. the spontaneous firing rate in the MVN was altered as follows. The type A pattern exhibited a transient increase, followed by a decrease. The type B pattern showed a gradual decrease, and no further changes after the onset of occlusion. Type A and B patterns were observed respectively in MVN ipsi- and contra-lateral to the VA occlusion. In contrast, the VG neuronal firing rate was not affected by the occlusion. These results seem to support the clinical suggestion that the vertigo in VBI is produced by a difference in the function between the bilateral vestibular nuclei. rather than by the peripheral vestibular nerve. PMID:9657307

Yamanaka, T; Yamamoto, T; Miyahara, H; Matsunaga, T

1998-01-01

3

Convergence of limb, visceral, and vertical semicircular canal or otolith inputs onto vestibular nucleus neurons  

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The major goal of this study was to determine the patterns of convergence of non-labyrinthine inputs from the limbs and viscera onto vestibular nucleus neurons receiving signals from vertical semicircular canals or otolith organs. A secondary aim was to ascertain whether the effects of non-labyrinthine inputs on the activity of vestibular nucleus neurons is affected by bilateral peripheral vestibular lesions. The majority (72%) of vestibular nucleus neurons in labyrinth-intact animals whose firing was modulated by vertical rotations responded to electrical stimulation of limb and/or visceral nerves. The activity of even more vestibular nucleus neurons (93%) was affected by limb or visceral nerve stimulation in chronically labyrinthectomized preparations. Some neurons received non-labyrinthine inputs from a variety of peripheral sources, including antagonist muscles acting at the same joint, whereas others received inputs from more limited sources. There was no apparent relationship between the spatial and dynamic properties of a neuron's responses to tilts in vertical planes and the non-labyrinthine inputs that it received. These data suggest that non-labyrinthine inputs elicited during movement will modulate the processing of information by the central vestibular system, and may contribute to the recovery of spontaneous activity of vestibular nucleus neurons following peripheral vestibular lesions. Furthermore, some vestibular nucleus neurons with non-labyrinthine inputs may be activated only during particular behaviors that elicit a specific combination of limb and visceral inputs.

Jian, B. J.; Shintani, T.; Emanuel, B. A.; Yates, B. J.

2002-01-01

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Heterogeneous Potassium Conductances Contribute to the Diverse Firing Properties of Postnatal Mouse Vestibular Ganglion Neurons  

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How mechanical information is encoded in the vestibular periphery has not been clarified. To begin to address the issue we examined the intrinsic firing properties of postnatal mouse vestibular ganglion neurons using the whole cell, tight-seal technique in current-clamp mode. We categorized two populations of neurons based on the threshold required to evoke an action potential. Low-threshold neurons fired with an average minimum current injection of ?43 pA, whereas high-threshold neurons re...

Risner, Jessica R.; Holt, Jeffrey R.

2006-01-01

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Mechanotransduction and hyperpolarization-activated currents contribute to spontaneous activity in mouse vestibular ganglion neurons.  

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The hyperpolarization-activated, cyclic nucleotide-sensitive current, Ih, is present in vestibular hair cells and vestibular ganglion neurons, and is required for normal balance function. We sought to identify the molecular correlates and functional relevance of Ih in vestibular ganglion neurons. Ih is carried by channels consisting of homo- or heteromeric assemblies of four protein subunits from the Hcn gene family. The relative expression of Hcn1-4 mRNA was examined using a quantitative reverse transcription PCR (RT-PCR) screen. Hcn2 was the most highly expressed subunit in vestibular neuron cell bodies. Immunolocalization of HCN2 revealed robust expression in cell bodies of all vestibular ganglion neurons. To characterize Ih in vestibular neuron cell bodies and at hair cell-afferent synapses, we developed an intact, ex vivo preparation. We found robust physiological expression of Ih in 89% of cell bodies and 100% of calyx terminals. Ih was significantly larger in calyx terminals than in cell bodies; however, other biophysical characteristics were similar. Ih was absent in calyces lacking Hcn1 and Hcn2, but small Ih was still present in cell bodies, which suggests expression of an additional subunit, perhaps Hcn4. To determine the contributions of hair cell mechanotransduction and Ih to the firing patterns of calyx terminals, we recorded action potentials in current-clamp mode. Mechanotransduction currents were modulated by hair bundle defection and application of calcium chelators to disrupt tip links. Ih activity was modulated using ZD7288 and cAMP. We found that both hair cell transduction and Ih contribute to the rate and regularity of spontaneous action potentials in the vestibular afferent neurons. We propose that modulation of Ih in vestibular ganglion neurons may provide a mechanism for modulation of spontaneous activity in the vestibular periphery. PMID:24638995

Horwitz, Geoffrey C; Risner-Janiczek, Jessica R; Holt, Jeffrey R

2014-04-01

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FMRFamide-related peptide expression in the vestibular-afferent neurons.  

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Vestibular-afferent neurons innervate hair cells from the sensory epithelia of vestibular end-organs and their action-potential discharge dynamics are driven by linear and angular accelerations of the head. The electrical activity of the vestibular-afferent neurons depends on their intrinsic properties and on the synaptic input from hair cells and from the terminals of the efferent system. Here we report that vestibular-afferent neurons of the rat are immunoreactive to RFamide-related peptides, and that the stronger signal comes from calyx-shaped neuron dendrites, with no signal detected in hair cells or supporting cells. The whole-cell voltage clamp recording of isolated afferent neurons showed that they express robust acid-sensing ionic currents (ASICs). Extracellular multiunit recordings of the vestibular nerve in a preparation in vitro of the rat inner ear showed that the perfusion of FMRFamide (a snail ortholog of this family of neuropeptides) exerts an excitatory effect on the afferent-neurons spike-discharge rate. Because the FMRFamide cannot activate the ASIC but reduces its desensitization generating a more robust current, its effect indicates that the ASIC are tonically active in the vestibular-afferent neurons and modulated by RFamide-like peptides. PMID:22342307

Mercado, Francisco; López, Iván; Ortega, Aida; Almanza, Angélica; Soto, Enrique; Vega, Rosario

2012-03-28

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Integration of vestibular and gastrointestinal inputs by cerebellar fastigial nucleus neurons: multisensory influences on motion sickness.  

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Previous studies demonstrated that ingestion of the emetic compound copper sulfate (CuSO4) alters the responses to vestibular stimulation of a large fraction of neurons in brainstem regions that mediate nausea and vomiting, thereby affecting motion sickness susceptibility. Other studies suggested that the processing of vestibular inputs by cerebellar neurons plays a critical role in generating motion sickness and that neurons in the cerebellar fastigial nucleus receive visceral inputs. These findings raised the hypothesis that stimulation of gastrointestinal receptors by a nauseogenic compound affects the processing of labyrinthine signals by fastigial nucleus neurons. We tested this hypothesis in decerebrate cats by determining the effects of intragastric injection of CuSO4 on the responses of rostral fastigial nucleus to whole-body rotations that activate labyrinthine receptors. Responses to vestibular stimulation of fastigial nucleus neurons were more complex in decerebrate cats than reported previously in conscious felines. In particular, spatiotemporal convergence responses, which reflect the convergence of vestibular inputs with different spatial and temporal properties, were more common in decerebrate than in conscious felines. The firing rate of a small percentage of fastigial nucleus neurons (15%) was altered over 50% by the administration of CuSO4; the firing rate of the majority of these cells decreased. The responses to vestibular stimulation of a majority of these cells were attenuated after the compound was provided. Although these data support our hypothesis, the low fraction of fastigial nucleus neurons whose firing rate and responses to vestibular stimulation were affected by the administration of CuSO4 casts doubt on the notion that nauseogenic visceral inputs modulate motion sickness susceptibility principally through neural pathways that include the cerebellar fastigial nucleus. Instead, it appears that convergence of gastrointestinal and vestibular inputs occurs mainly in the brainstem. PMID:24677139

Catanzaro, Michael F; Miller, Daniel J; Cotter, Lucy A; McCall, Andrew A; Yates, Bill J

2014-08-01

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Neuronal detection thresholds during vestibular compensation: contributions of response variability and sensory substitution.  

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The vestibular system is responsible for processing self-motion, allowing normal subjects to discriminate the direction of rotational movements as slow as 1-2 deg s(-1). After unilateral vestibular injury patients' direction-discrimination thresholds worsen to ?20 deg s(-1), and despite some improvement thresholds remain substantially elevated following compensation. To date, however, the underlying neural mechanisms of this recovery have not been addressed. Here, we recorded from first-order central neurons in the macaque monkey that provide vestibular information to higher brain areas for self-motion perception. Immediately following unilateral labyrinthectomy, neuronal detection thresholds increased by more than two-fold (from 14 to 30 deg s(-1)). While thresholds showed slight improvement by week 3 (25 deg s(-1)), they never recovered to control values - a trend mirroring the time course of perceptual thresholds in patients. We further discovered that changes in neuronal response variability paralleled changes in sensitivity for vestibular stimulation during compensation, thereby causing detection thresholds to remain elevated over time. However, we found that in a subset of neurons, the emergence of neck proprioceptive responses combined with residual vestibular modulation during head-on-body motion led to better neuronal detection thresholds. Taken together, our results emphasize that increases in response variability to vestibular inputs ultimately constrain neural thresholds and provide evidence that sensory substitution with extravestibular (i.e. proprioceptive) inputs at the first central stage of vestibular processing is a neural substrate for improvements in self-motion perception following vestibular loss. Thus, our results provide a neural correlate for the patient benefits provided by rehabilitative strategies that take advantage of the convergence of these multisensory cues. PMID:24366259

Jamali, Mohsen; Mitchell, Diana E; Dale, Alexis; Carriot, Jerome; Sadeghi, Soroush G; Cullen, Kathleen E

2014-04-01

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Monoclonal L-citrulline immunostaining reveals nitric oxide-producing vestibular neurons  

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Nitric oxide is an unstable free radical that serves as a novel messenger molecule in the central nervous system (CNS). In order to understand the interplay between classic and novel chemical communication systems in vestibular pathways, the staining obtained using a monoclonal antibody directed against L-citrulline was compared with the labeling observed using more traditional markers for the presence of nitric oxide. Brainstem tissue from adult rats was processed for immunocytochemistry employing a monoclonal antibody directed against L-citrulline, a polyclonal antiserum against neuronal nitric oxide synthase, and/or NADPH-diaphorase histochemistry. Our findings demonstrate that L-citrulline can be fixed in situ by vascular perfusion, and can be visualized in fixed CNS tissue sections by immunocytochemistry. Further, the same vestibular regions and cell types are labeled by NADPH-diaphorase histochemistry, by the neuronal nitric oxide synthase antiserum, and by our anti-L-citrulline antibody. Clusters of L-citrulline-immunoreactive neurons are present in subregions of the vestibular nuclei, including the caudal portion of the inferior vestibular nucleus, the magnocellular portion of the medial vestibular nucleus, and the large cells in the ventral tier of the lateral vestibular nucleus. NADPH-diaphorase histochemical staining of these neurons clearly demonstrated their multipolar, fusiform and globular somata and long varicose dendritic processes. These results provide support for the suggestion that nitric oxide serves key roles in both vestibulo-autonomic and vestibulo-spinal pathways.

Holstein, G. R.; Friedrich, V. L. Jr; Martinelli, G. P.

2001-01-01

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A clinical observation of benign paroxysmal positional vertigo (BPPV) after vestibular neuronitis (VN).  

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We observed 9 cases of BPPV developed after vestibular neuronitis. The interval between the onset of BPPV and vestibular neuronitis ranged from 2 weeks to 20 years. All cases were examined for critical head position which provoked vertigo, non-gaze nystagmus, positional and positioning nystagmus and caloric nystagmus. No characteristic signs and symptoms could be observed. The function of the posterior canal is thought to be necessary to provoke positional vertigo. Thus in BPPV after vestibular neuronitis the function of the posterior canal would presumably have been preserved to some degree. The first possibility is that the function of the posterior canal was not impaired in spite of the damage of the lateral canal. The fact that each canal differs in involvement in vestibular neuronitis may be explained by the difference in the blood supply or the innervation between lateral and posterior canals. If only the artery or nerve which is related to the lateral canal is damaged and the artery or nerve to the posterior canal is not involved, then the function of the posterior canal is preserved. So BPPV may occur soon after the disappearance of severe vertigo. The second possibility is that if the posterior canal had been damaged together with the lateral canal and the functions are recovering, BPPV may occur some time after the onset of vestibular neuronitis. The locus of vestibular neuronitis is in the peripheral vestibular system and the extent and degree of the lesion vary, which may explain why there can be time difference of the recovery between the two canals. PMID:8470503

Harada, K; Oda, M; Yamamoto, M; Nomura, T; Ohbayashi, S; Kitsuda, C

1993-01-01

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Ion Channels Set Spike Timing Regularity of Mammalian Vestibular Afferent Neurons  

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In the mammalian vestibular nerve, some afferents have highly irregular interspike intervals and others have highly regular intervals. To investigate whether spike timing is determined by the afferents' ion channels, we studied spiking activity in their cell bodies, isolated from the vestibular ganglia of young rats. Whole cell recordings were made with the perforated-patch method. As previously reported, depolarizing current steps revealed distinct firing patterns. Transient neurons fired on...

Kalluri, Radha; Xue, Jingbing; Eatock, Ruth Anne

2010-01-01

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Molecular developmental neurobiology of formation, guidance and survival of primary vestibular neurons  

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Untangling the molecular and physiological interactions that generate the proper connections of the primary vestibular neurons in normal gravity requires two parallel approaches. One approach needs to use mutant mice to delineate the molecular basis of developmental mechanisms that govern ear development, including formation and differentiation of neurons and establishment of their peripheral and central connections. Beyond that and in addition to it, we need physiological investigations using microgravity and/or hypergravity, as well as absence of otoconia, to understand the role played by vestibular stimuli to fine tune connections of primary and secondary vestibular neurons. This paper provides an overview of some of the molecular mechanisms uncovered over the last few years that guide development, differentiation and survival of primary vestibular neurons of the mammalian ear. Briefly, several genes that are essential for primary neuron formation have been identified, all genes that govern embryonic survival are known and the first genes and mechanisms that guide formation of proper connections are being revealed. While still incomplete, the progress has been astounding and the completion of the mouse genome project will further accelerate the pace. Such data pave the way to put the research on the influence of altered gravity stimulation within a molecular framework.

Fritzsch, B.

2003-10-01

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Binocular disparity tuning and visual-vestibular congruency of multisensory neurons in macaque parietal cortex.  

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Many neurons in the dorsal medial superior temporal (MSTd) and ventral intraparietal (VIP) areas of the macaque brain are multisensory, responding to both optic flow and vestibular cues to self-motion. The heading tuning of visual and vestibular responses can be either congruent or opposite, but only congruent cells have been implicated in cue integration for heading perception. Because of the geometric properties of motion parallax, however, both congruent and opposite cells could be involved in coding self-motion when observers fixate a world-fixed target during translation, if congruent cells prefer near disparities and opposite cells prefer far disparities. We characterized the binocular disparity selectivity and heading tuning of MSTd and VIP cells using random-dot stimuli. Most (70%) MSTd neurons were disparity selective with monotonic tuning, and there was no consistent relationship between depth preference and congruency of visual and vestibular heading tuning. One-third of disparity-selective MSTd cells reversed their depth preference for opposite directions of motion [direction-dependent disparity tuning (DDD)], but most of these cells were unisensory with no tuning for vestibular stimuli. Inconsistent with previous reports, the direction preferences of most DDD neurons do not reverse with disparity. By comparison to MSTd, VIP contains fewer disparity-selective neurons (41%) and very few DDD cells. On average, VIP neurons also preferred higher speeds and nearer disparities than MSTd cells. Our findings are inconsistent with the hypothesis that visual/vestibular congruency is linked to depth preference, and also suggest that DDD cells are not involved in multisensory integration for heading perception. PMID:22159105

Yang, Yun; Liu, Sheng; Chowdhury, Syed A; DeAngelis, Gregory C; Angelaki, Dora E

2011-12-01

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Neurosteroid modulation of neuronal excitability and synaptic transmission in the rat medial vestibular nuclei.  

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In rat brainstem slices, we investigated the influence of the neurosteroids tetrahydrodeoxycorticosterone (THDOC) and allopregnanolone (ALLO) on the synaptically driven and spontaneous activity of vestibular neurons, by analysing their effects on the amplitude of the field potentials evoked in the medial vestibular nuclei (MVN) by vestibular afferent stimulation and on the spontaneous firing rate of MVN neurons. Furthermore, the interaction with gamma-aminobutyric acid (GABA) and glutamate receptors was analysed by using specific antagonists for GABA(A) (bicuculline), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/ kainate [2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo(f)quinoxaline-7-sulphonamide disodium salt (NBQX)], N-methyl-D-aspartate (NMDA) [D-(-)-2-amino-5-phosphonopentanoic acid (AP-5)] and group I metabotropic glutamate receptors (mGlu-I) [(R,S)-1-aminoindan-1,5-dicarboxylic acid (AIDA)] receptors. THDOC and ALLO evoked two opposite long-lasting effects, consisting of either a potentiation or a reduction of field potential and firing rate, which showed early and late components, occurring in conjunction or separately after neurosteroid application. The depressions depended on GABA(A) receptors, as they were abolished by bicuculline, while early potentiation involved glutamate AMPA/kainate receptors, as NBQX markedly reduced the incidence of early firing rate enhancement and, in the case of ALLO, even provoked depression. This suggests that THDOC and ALLO enhance the GABA(A) inhibitory influence on the MVN neurons and facilitate the AMPA/kainate facilitatory one. Conversely, a late potentiation effect, which was still induced after glutamate and GABA(A) receptor blockade, might involve a different mechanism. We conclude that the modulation of neuronal activity in the MVN by THDOC and ALLO, through their actions on GABA(A) and AMPA/kainate receptors, may have a physiological role in regulating the vestibular system function under normal conditions and during the stress response that accompanies many forms of vestibular dysfunction. PMID:17596193

Grassi, Silvarosa; Frondaroli, Adele; Dieni, Cristina; Dutia, Mayank B; Pettorossi, Vito E

2007-07-01

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Pulsed infrared radiation excites cultured neonatal spiral and vestibular ganglion neurons by modulating mitochondrial calcium cycling.  

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Cochlear implants are currently the most effective solution for profound sensorineural hearing loss, and vestibular prostheses are under development to treat bilateral vestibulopathies. Electrical current spread in these neuroprostheses limits channel independence and, in some cases, may impair their performance. In comparison, optical stimuli that are spatially confined may result in a significant functional improvement. Pulsed infrared radiation (IR) has previously been shown to elicit responses in neurons. This study analyzes the response of neonatal rat spiral and vestibular ganglion neurons in vitro to IR (wavelength = 1,863 nm) using Ca(2+) imaging. Both types of neurons responded consistently with robust intracellular Ca(2+) ([Ca(2+)]i) transients that matched the low-frequency IR pulses applied (4 ms, 0.25-1 pps). Radiant exposures of ?637 mJ/cm(2) resulted in continual neuronal activation. Temperature or [Ca(2+)] variations in the media did not alter the IR-evoked transients, ruling out extracellular Ca(2+) involvement or primary mediation by thermal effects on the plasma membrane. While blockage of Na(+), K(+), and Ca(2+) plasma membrane channels did not alter the IR-evoked response, blocking of mitochondrial Ca(2+) cycling with CGP-37157 or ruthenium red reversibly inhibited the IR-evoked [Ca(2+)]i transients. Additionally, the magnitude of the IR-evoked transients was dependent on ryanodine and cyclopiazonic acid-dependent Ca(2+) release. These results suggest that IR modulation of intracellular calcium cycling contributes to stimulation of spiral and vestibular ganglion neurons. As a whole, the results suggest selective excitation of neurons in the IR beam path and the potential of IR stimulation in future auditory and vestibular prostheses. PMID:24920028

Lumbreras, Vicente; Bas, Esperanza; Gupta, Chhavi; Rajguru, Suhrud M

2014-09-15

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Retrograde transport of [3H]-D-aspartate label by cochlear and vestibular efferent neurons.  

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[3H]-D-aspartic acid was injected into the inner ear of rats. After a six hour survival time, labeled cells were found at all locations known to contain efferent cochlear or vestibular neurons. Most labeled neurons were found in the ipsilateral lateral superior olivary nucleus (LSO), although both ventral nuclei of the trapezoid body (VTB), group E, and the caudal pontine reticular nucleus (CPR) just adjacent to the ascending limb of the facial nerve also contained labeled cells. Because not all efferent neurons in the rat could be previously shown to be cholinergic, aspartate and glutamate are efferent transmitter candidates. PMID:3258736

Schwarz, D W; Schwarz, I E

1988-01-01

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Retrograde transport of [3H]-D-aspartate label by cochlear and vestibular efferent neurons  

International Nuclear Information System (INIS)

[3H]-D-aspartic acid was injected into the inner ear of rats. After a six hour survival time, labeled cells were found at all locations known to contain efferent cochlear or vestibular neurons. Most labeled neurons were found in the ipsilateral lateral superior olivary nucleus (LSO), although both ventral nuclei of the trapezoid body (VTB), group E, and the caudal pontine reticular nucleus (CPR) just adjacent to the ascending limb of the facial nerve also contained labeled cells. Because not all efferent neurons in the rat could be previously shown to be cholinergic, aspartate and glutamate are efferent transmitter candidates

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A model for the characterization of the spatial properties in vestibular neurons  

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Quantitative study of the static and dynamic response properties of some otolith-sensitive neurons has been difficult in the past partly because their responses to different linear acceleration vectors exhibited no "null" plane and a dependence of phase on stimulus orientation. The theoretical formulation of the response ellipse provides a quantitative way to estimate the spatio-temporal properties of such neurons. Its semi-major axis gives the direction of the polarization vector (i.e., direction of maximal sensitivity) and it estimates the neuronal response for stimulation along that direction. In addition, the semi-minor axis of the ellipse provides an estimate of the neuron's maximal sensitivity in the "null" plane. In this paper, extracellular recordings from otolith-sensitive vestibular nuclei neurons in decerebrate rats were used to demonstrate the practical application of the method. The experimentally observed gain and phase dependence on the orientation angle of the acceleration vector in a head-horizontal plane was described and satisfactorily fit by the response ellipse model. In addition, the model satisfactorily fits neuronal responses in three-dimensions and unequivocally demonstrates that the response ellipse formulation is the general approach to describe quantitatively the spatial properties of vestibular neurons.

Angelaki, D. E.; Bush, G. A.; Perachio, A. A.

1992-01-01

19

Three-dimensional analysis of vestibular efferent neurons innervating semicircular canals of the gerbil  

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Anterograde labeling techniques were used to examine peripheral innervation patterns of vestibular efferent neurons in the crista ampullares of the gerbil. Vestibular efferent neurons were labeled by extracellular injections of biocytin or biotinylated dextran amine into the contralateral or ipsilateral dorsal subgroup of efferent cell bodies (group e) located dorsolateral to the facial nerve genu. Anterogradely labeled efferent terminal field varicosities consist mainly of boutons en passant with fewer of the terminal type. The bouton swellings are located predominately in apposition to the basolateral borders of the afferent calyces and type II hair cells, but several boutons were identified close to the hair cell apical border on both types. Three-dimensional reconstruction and morphological analysis of the terminal fields from these cells located in the sensory neuroepithelium of the anterior, horizontal, and posterior cristae were performed. We show that efferent neurons densely innervate each end organ in widespread terminal fields. Subepithelial bifurcations of parent axons were minimal, with extensive collateralization occurring after the axons penetrated the basement membrane of the neuroepithelium. Axonal branching ranged between the 6th and 27th orders and terminal field collecting area far exceeds that of the peripheral terminals of primary afferent neurons. The terminal fields of the efferent neurons display three morphologically heterogeneous types: central, peripheral, and planum. All cell types possess terminal fields displaying a high degree of anisotropy with orientations typically parallel to or within +/-45 degrees of the longitudinal axis if the crista. Terminal fields of the central and planum zones predominately project medially toward the transverse axis from the more laterally located penetration of the basement membrane by the parent axon. Peripheral zone terminal fields extend predominately toward the planum semilunatum. The innervation areas of efferent terminal fields display a trend from smallest to largest for the central, peripheral, and planum types, respectively. Neurons that innervate the central zone of the crista do not extend into the peripheral or planum regions. Conversely, those neurons with terminal fields in the peripheral or planum regions do not innervate the central zone of the sensory neuroepithelium. The central zone of the crista is innervated preferentially by efferent neurons with cell bodies located in the ipsilateral group e. The peripheral and planum zones of the crista are innervated preferentially by efferent neurons with cell bodies located in the contralateral group e. A model incorporating our anatomic observations is presented describing an ipsilateral closed-loop feedback between ipsilateral efferent neurons and the periphery and an open-loop feed-forward innervation from contralateral efferent neurons. A possible role for the vestibular efferent neurons in the modulation of semicircular canal afferent response dynamics is proposed.

Purcell, I. M.; Perachio, A. A.

1997-01-01

20

Inputs from regularly and irregularly discharging vestibular nerve afferents to secondary neurons in squirrel monkey vestibular nuclei. III. Correlation with vestibulospinal and vestibuloocular output pathways  

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1. A previous study measured the relative contributions made by regularly and irregularly discharging afferents to the monosynaptic vestibular nerve (Vi) input of individual secondary neurons located in and around the superior vestibular nucleus of barbiturate-anesthetized squirrel monkeys. Here, the analysis is extended to more caudal regions of the vestibular nuclei, which are a major source of both vestibuloocular and vestibulospinal pathways. As in the previous study, antidromic stimulation techniques are used to classify secondary neurons as oculomotor or spinal projecting. In addition, spinal-projecting neurons are distinguished by their descending pathways, their termination levels in the spinal cord, and their collateral projections to the IIIrd nucleus. 2. Monosynaptic excitatory postsynaptic potentials (EPSPs) were recorded intracellularly from secondary neurons as shocks of increasing strength were applied to Vi. Shocks were normalized in terms of the threshold (T) required to evoke field potentials in the vestibular nuclei. As shown previously, the relative contribution of irregular afferents to the total monosynaptic Vi input of each secondary neuron can be expressed as a %I index, the ratio (x100) of the relative sizes of the EPSPs evoked by shocks of 4 x T and 16 x T. 3. Antidromic stimulation was used to type secondary neurons as 1) medial vestibulospinal tract (MVST) cells projecting to spinal segments C1 or C6; 2) lateral vestibulospinal tract (LVST) cells projecting to C1, C6; or L1; 3) vestibulooculo-collic (VOC) cells projecting both to the IIIrd nucleus and by way of the MVST to C1 or C6; and 4) vestibuloocular (VOR) neurons projecting to the IIIrd nucleus but not to the spinal cord. Most of the neurons were located in the lateral vestibular nucleus (LV), including its dorsal (dLV) and ventral (vLV) divisions, and adjacent parts of the medial (MV) and descending nuclei (DV). Cells receiving quite different proportions of their direct inputs from regular and irregular afferents were intermingled in all regions explored. 4. LVST neurons are restricted to LV and DV and show a somatotopic organization. Those destined for the cervical and thoracic cord come from vLV, from a transition zone between vLV and DV, and to a lesser extent from dLV. Lumbar-projecting neurons are located more dorsally in dLV and more caudally in DV. MVST neurons reside in MV and in the vLV-DV transition zone.(ABSTRACT TRUNCATED AT 400 WORDS).

Boyle, R.; Goldberg, J. M.; Highstein, S. M.

1992-01-01

 
 
 
 
21

Transfer characteristics of first and second order lateral canal vestibular neurons in gerbil.  

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Discharge patterns of first and second order vestibular neurons responding to angular acceleration in the plane of the lateral canals were studied in gerbil. The resting discharge activity of each cell was used to characterize the neuron by measureing the coefficient of variation and coefficient of skewness of the interspike interval distributions. Sinusoidal angular oscillations ranging in frequency from 0.0125 to 5.0 Hz were delivered by a velocity controlled rate-table. A PDP-12 minicomputer system was used on-line to display period and post-stimulus histograms of discriminated single unit activity. Off-line Fourier analysis of the period histograms was used to determine the phase of cell response to sinusoidal accelerations, while the average level and amplitude were determined by a least squares fitting algorithm applied over the fraction of the stimulus period where the cell discharged. First order neurons were found to have high discharge rates (average = 61.7 imp./sec) and bidirectional responses to rotation, and were of two groups called regular and irregular according to their resting discharge patterns. Second order neurons, located mainly in the medial and lateral vestibular nuclei, had low or even zero resting discharge rates (average = 17.8) resulting in more uni-directional responses and were of a single population. For frequencies less than 10 Hz, the Bode plots of the regular first order neurons are similar to that of a first order system with a time constant of about 2 sec as predicted by the torsion pendulum theory for cupula movement. The irregular first order neurons show an increasing gain above 0.5 Hz and a large phase lead relative to angular velocity above 1.0 Hz suggestive of a fractional power transfer function. The second order neurons show the phase and gain characteristics of the regular first order neurons being in phase with angular velocity above 1.0 Hz. PMID:947494

Schneider, L W; Anderson, D J

1976-08-01

22

The effects of bilateral vestibular loss on hippocampal volume, neuronal number and cell proliferation in rats  

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Full Text Available Previous studies in humans have shown that bilateral loss of vestibular function is associated with a significant bilateral atrophy of the hippocampus, which correlated with the patients’ spatial memory deficits. More recently, patients who had recovered from unilateral vestibular neuritis have been reported to exhibit a significant atrophy of the left posterior hippocampus. Therefore, we investigated whether bilateral vestibular deafferentation (BVD would result in a decrease in neuronal number or volume in the rat hippocampus, using stereological methods. At 16 months post-BVD, we found no significant differences in hippocampal neuronal number or volume compared to sham controls, despite the fact that these animals exhibited severe spatial memory deficits. By contrast, using bromodeoxyuridine (BrdU as a marker of cell proliferation, we found that the number of BrdU-labelled cells significantly increased in the dentate gyrus of the hippocampus between 48 h and 1 week following BVD. Although a substantial proportion of these cells survived for up to 1 month, the survival rate was significantly lower in BVD animals when compared with that in sham animals. These results suggest a dissociation between the effects of BVD on spatial memory and hippocampal structure in rats and humans, which cannot be explained by an injury-induced increase in cell proliferation.

PaulSmith

2012-02-01

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Spatiotemporal processing of linear acceleration: primary afferent and central vestibular neuron responses  

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Spatiotemporal convergence and two-dimensional (2-D) neural tuning have been proposed as a major neural mechanism in the signal processing of linear acceleration. To examine this hypothesis, we studied the firing properties of primary otolith afferents and central otolith neurons that respond exclusively to horizontal linear accelerations of the head (0.16-10 Hz) in alert rhesus monkeys. Unlike primary afferents, the majority of central otolith neurons exhibited 2-D spatial tuning to linear acceleration. As a result, central otolith dynamics vary as a function of movement direction. During movement along the maximum sensitivity direction, the dynamics of all central otolith neurons differed significantly from those observed for the primary afferent population. Specifically at low frequencies (neurons peaked in phase with linear velocity, in contrast to primary afferents that peaked in phase with linear acceleration. At least three different groups of central response dynamics were described according to the properties observed for motion along the maximum sensitivity direction. "High-pass" neurons exhibited increasing gains and phase values as a function of frequency. "Flat" neurons were characterized by relatively flat gains and constant phase lags (approximately 20-55 degrees ). A few neurons ("low-pass") were characterized by decreasing gain and phase as a function of frequency. The response dynamics of central otolith neurons suggest that the approximately 90 degrees phase lags observed at low frequencies are not the result of a neural integration but rather the effect of nonminimum phase behavior, which could arise at least partly through spatiotemporal convergence. Neither afferent nor central otolith neurons discriminated between gravitational and inertial components of linear acceleration. Thus response sensitivity was indistinguishable during 0.5-Hz pitch oscillations and fore-aft movements. The fact that otolith-only central neurons with "high-pass" filter properties exhibit semicircular canal-like dynamics during head tilts might have important consequences for the conclusions of previous studies of sensory convergence and sensorimotor transformations in central vestibular neurons.

Angelaki, D. E.; Dickman, J. D.

2000-01-01

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Bone conducted vibration selectively activates irregular primary otolithic vestibular neurons in the guinea pig.  

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The main objective of this study was to determine whether bone-conducted vibration (BCV) is equally effective in activating both semicircular canal and otolith afferents in the guinea pig or whether there is preferential activation of one of these classes of vestibular afferents. To answer this question a large number (346) of single primary vestibular neurons were recorded extracellularly in anesthetized guinea pigs and were identified by their location in the vestibular nerve and classed as regular or irregular on the basis of the variability of their spontaneous discharge. If a neuron responded to angular acceleration it was classed as a semicircular canal neuron, if it responded to maintained roll or pitch tilts it was classified as an otolith neuron. Each neuron was then tested by BCV stimuli-either clicks, continuous pure tones (200-1,500 Hz) or short tone bursts (500 Hz lasting 7 ms)-delivered by a B-71 clinical bone-conduction oscillator cemented to the guinea pig's skull. All stimulus intensities were referred to that animal's own auditory brainstem response (ABR) threshold to BCV clicks, and the maximum intensity used was within the animal's physiological range and was usually around 70 dB above BCV threshold. In addition two sensitive single axis linear accelerometers cemented to the skull gave absolute values of the stimulus acceleration in the rostro-caudal direction. The criterion for a neuron being classed as activated was an audible, stimulus-locked increase in firing rate (a 10% change was easily detectable) in response to the BCV stimulus. At the stimulus levels used in this study, semicircular canal neurons, both regular and irregular, were insensitive to BCV stimuli and very few responded: only nine of 189 semicircular canal neurons tested (4.7%) showed a detectable increase in firing in response to BCV stimuli up to the maximum 2 V peak-to-peak level we delivered to the B-71 oscillator (which produced a peak-to-peak skull acceleration of around 6-8 g and was usually around 60-70 dB above the animal's own ABR threshold for BCV clicks). Regular otolithic afferents likewise had a poor response; only 14 of 99 tested (14.1%) showed any increase in firing rate up to the maximum BCV stimulus level. However, most irregular otolithic afferents (82.8%) showed a clear increase in firing rate in response to BCV stimuli: of the 58 irregular otolith neurons tested, 48 were activated, with some being activated at very low intensities (only about 10 dB above the animal's ABR threshold to BCV clicks). Most of the activated otolith afferents were in the superior division of the vestibular nerve and were probably utricular afferents. That was confirmed by evidence using juxtacellular injection of neurobiotin near BCV activated neurons to trace their site of origin to the utricular macula. We conclude there is a very clear preference for irregular otolith afferents to be activated selectively by BCV stimuli at low stimulus levels and that BCV stimuli activate some utricular irregular afferent neurons. The BCV generates compressional and shear waves, which travel through the skull and constitute head accelerations, which are sufficient to stimulate the most sensitive otolithic receptor cells. PMID:16761136

Curthoys, Ian S; Kim, Juno; McPhedran, Samara K; Camp, Aaron J

2006-11-01

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Histamine excites neurons of the inferior vestibular nucleus in rats by activation of H1 and H2 receptors.  

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By using brain slice preparations and extracellular recordings, the effect of histamine on spontaneous firing activities of neurons in the inferior vestibular nucleus (IVN), a key structure responsible for integration of vestibular, multisensory, and cerebellar inputs, in rats was investigated. Perfusing slices with histamine (1-10?M) elicited an excitatory response on IVN neurons. The responses were not blocked by low Ca(2+)/high Mg(2+) medium, indicating a direct postsynaptic effect of the amine. Furthermore, the histamine-induced excitation was partially blocked by selective histamine H1 receptor antagonist mepyramine (1?M) and H2 receptor antagonist ranitidine (1?M), respectively. Co-application of mepyramine and ranitidine nearly totally antagonized the histamine-induced excitation. Additionally, both selective H1 receptor agonist 2-pyridylethylamine (30-300?M) and H2 receptor agonist dimaprit (10-100?M) effectively mimicked the excitatory action of histamine on IVN neurons. Moreover, selective H4 antagonist JNJ7777120 (10?M) and agonist VUF8430 (30-300?M) had no effect on IVN neurons. These results demonstrate that histamine excites IVN neurons via postsynaptic H1 and H2 rather than H4 receptors, and suggest that the central histaminergic system actively modulate all four major vestibular nuclei including the IVN and may subsequently influence the vestibular nuclei-related reflexes and functions. PMID:23466693

Peng, Shi-Yu; Zhuang, Qian-Xing; He, Ye-Cheng; Zhu, Jing-Ning; Wang, Jian-Jun

2013-04-29

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Vestibular integrator neurons have quadratic functions due to voltage dependent conductances.  

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The nonlinear properties of the dendrites of the prepositus hypoglossi nucleus (PHN) neurons are essential for the operation of the vestibular neural integrator that converts a head velocity signal to one that controls eye position. A novel system of frequency probing, namely quadratic sinusoidal analysis (QSA), was used to decode the intrinsic nonlinear behavior of these neurons under voltage clamp conditions. Voltage clamp currents were measured at harmonic and interactive frequencies using specific nonoverlapping stimulation frequencies. Eigenanalysis of the QSA matrix reduces it to a remarkably compact processing unit, composed of just one or two dominant components (eigenvalues). The QSA matrix of rat PHN neurons provides signatures of the voltage dependent conductances for their particular dendritic and somatic distributions. An important part of the nonlinear response is due to the persistent sodium conductance (gNaP), which is likely to be essential for sustained effects needed for a neural integrator. It was found that responses in the range of 10 mV peak to peak could be well described by quadratic nonlinearities suggesting that effects of higher degree nonlinearities would add only marginal improvement. Therefore, the quadratic response is likely to sufficiently capture most of the nonlinear behavior of neuronal systems except for extremely large synaptic inputs. Thus, neurons have two distinct linear and quadratic functions, which shows that piecewise linear?+?quadratic analysis is much more complete than just piecewise linear analysis; in addition quadratic analysis can be done at a single holding potential. Furthermore, the nonlinear neuronal responses contain more frequencies over a wider frequency band than the input signal. As a consequence, they convert limited amplitude and bandwidth input signals to wider bandwidth and more complex output responses. Finally, simulations at subthreshold membrane potentials with realistic PHN neuron models suggest that the quadratic functions are fundamentally dominated by active dendritic structures and persistent sodium conductances. PMID:23519443

Magnani, Christophe; Eugène, Daniel; Idoux, Erwin; Moore, Lee E

2013-12-01

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Integrative responses of neurons in parabrachial nuclei to a nauseogenic gastrointestinal stimulus and vestibular stimulation in vertical planes.  

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The parabrachial and adjacent Kölliker-Fuse (PBN/KF) nuclei play a key role in relaying visceral afferent inputs to the hypothalamus and limbic system and are, thus, believed to participate in generating nausea and affective responses elicited by gastrointestinal (GI) signals. In addition, the PBN/KF region receives inputs from the vestibular system and likely mediates the malaise associated with motion sickness. However, previous studies have not considered whether GI and vestibular inputs converge on the same PBN/KF neurons, and if so, whether the GI signals alter the responses of the cells to body motion. The present study, conducted in decerebrate cats, tested the hypothesis that intragastric injection of copper sulfate, which elicits emesis by irritating the stomach lining, modifies the sensitivity of PBN/KF neurons to vertical plane rotations that activate vestibular receptors. Intragastric copper sulfate produced a 70% median change in the gain of responses to vertical plane rotations of PBN/KF units, whose firing rate was modified by the administration of the compound; the response gains for 16 units increased and those for 17 units decreased. The effects were often dramatic: out of 51 neurons tested, 13 responded to the rotations only after copper sulfate was injected, whereas 10 others responded only before drug delivery. These data show that a subset of PBN/KF neurons, whose activity is altered by a nauseogenic stimulus also respond to body motion and that irritation of the stomach lining can either cause an amplification or reduction in the sensitivity of the units to vestibular inputs. The findings imply that nausea and affective responses to vestibular stimuli may be modified by the presence of emetic signals from the GI system. PMID:22277934

Suzuki, Takeshi; Sugiyama, Yoichiro; Yates, Bill J

2012-04-15

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Histamine excites rat superior vestibular nuclear neurons via postsynaptic H1 and H2 receptors in vitro.  

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The superior vestibular nucleus (SVN), which holds a key position in vestibulo-ocular reflexes and nystagmus, receives direct hypothalamic histaminergic innervations. By using rat brainstem slice preparations and extracellular unitary recordings, we investigated the effect of histamine on SVN neurons and the underlying receptor mechanisms. Bath application of histamine evoked an excitatory response of the SVN neurons, which was not blocked by the low-Ca(2+)/high-Mg(2+) medium, indicating a direct postsynaptic effect of the amine. Selective histamine H1 receptor agonist 2-pyridylethylamine and H2 receptor agonist dimaprit, rather than VUF8430, a selective H4 receptor agonist, mimicked the excitation of histamine on SVN neurons. In addition, selective H1 receptor antagonist mepyramine and H2 receptor antagonist ranitidine, but not JNJ7777120, a selective H4 receptor antagonist, partially blocked the excitatory response of SVN neurons to histamine. Moreover, mepyramine together with ranitidine nearly totally blocked the histamine-induced excitation. Immunostainings further showed that histamine H1 and H2 instead of H4 receptors existed in the SVN. These results demonstrate that histamine excites the SVN neurons via postsynaptic histamine H1 and H2 receptors, and suggest that the central histaminergic innervation from the hypothalamus may actively bias the SVN neuronal activity and subsequently modulate the SVN-mediated vestibular functions and gaze control. PMID:23006827

Zhuang, Qian-Xing; Wu, Yong-Hui; Wu, Guan-Yi; Zhu, Jing-Ning; Wang, Jian-Jun

2013-01-01

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Response of pontomedullary reticulospinal neurons to vestibular stimuli in vertical planes. Role in vertical vestibulospinal reflexes of the decerebrate cat  

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1. To investigate the neural substrate of vestibulospinal reflexes in decerebrate cats, we studied the responses of pontomedullary reticulospinal neurons to natural stimulation of the labyrinth in vertical planes. Our principal aim was to determine whether reticulospinal neurons that terminate in, or are likely to give off collaterals to, the upper cervical segments had properties similar to those of the vestibulocollic reflex (VCR). 2. Antidromic stimulation was used to determine whether the neurons projected to the neck, lower cervical, thoracic, or lumbar levels. Dynamics of the responses of spontaneously firing neurons were studied with sinusoidal stimuli delivered at 0.05-1 Hz and aligned to the plane of body rotation, that produced maximal modulation of the neuron (response vector orientation). Each neuron was assigned a vestibular input classification of otolith, vertical canal, otolith + canal, or spatial-temporal convergence (STC). 3. We found, in agreement with previous studies, that the largest fraction of pontomedullary reticulospinal neurons projected to the lumbar cord, and that only a small number ended in the neck segments. Neurons projecting to all levels of the spinal cord had similar responses to labyrinth stimulation. 4. Reticulospinal neurons that received only vertical canal inputs were rare (1 of 67 units). Most reticulospinal neurons (48%) received predominant otolith inputs, 18% received otolith + canal input, and only 9% had STC behavior. These data are in sharp contrast to the results of our previous studies of vestibulospinal neurons. A considerable portion of vestibulospinal neurons receives vertical canal input (38%), fewer receive predominantly otolith input (22%), whereas the proportion that have otolith + canal input or STC behavior is similar to our present reticulospinal data. 5. The response vector orientations of our reticulospinal neurons, particularly those with canal inputs (canal, otolith + canal, STC) were predominantly in the roll quadrants. There was no evidence of convergence of inputs from like canals across the midline (e.g., right anterior + left anterior). 6. Two characteristics of the VCR, STC behavior and bilateral input from symmetric vertical canals (in some muscles), cannot be accounted for by the reticulospinal neurons that we studied. Because these characteristics are also not seen in vestibulocollic neurons, they are likely to be the result of the appropriate convergence of vestibular signals in the spinal cord. 7. Pontomedullary reticulospinal neurons seem particularly well suited to play a role in gravity-dependent postural reflexes of neck and limbs.

Bolton, P. S.; Goto, T.; Schor, R. H.; Wilson, V. J.; Yamagata, Y.; Yates, B. J.

1992-01-01

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THE COMPARATIVE CHARACTERISTICS OF BACKGROUND IMPULSE ACTIVITY OF IPSI- AND CONTRALATERAL MEDIAL VESTIBULAR NUCLUS NEURONS IN LABYRINTHECTOMIZED RATS  

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Full Text Available The background neuronal impulse activity of right and left medial vestibular nuclei of rats was carried out in norm and after unilateral labyrinthectomy (UL on 2-d, 7-th, 12-th and 17-th days. It was shown by computer analysis, that characteristics of both nuclei neurons impulse activity in the control group have revealled primery asymmetry of the average freguency of variation (accordingly 16,6±1,7 Hz; and 23,6±1,5 Hz; p<0,01. It is shown that on 7-th day following UL value of the average frequency corresponded to source (16,6±1,2 Hz and 23,6±1,7Hz.We discussed particularities of the process to compensations and functional importance got result.

S.H.Sarkisyan

2011-02-01

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Noradrenergic modulation of neuronal responses to n-methyl-d-aspartate in the vestibular nuclei: an electrophysiological and immunohistochemical study.  

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Excitatory responses evoked by N-methyl-d-aspartate (NMDA) in the vestibular nuclei (VN) of the rat were studied in vivo during microiontophoretic application of noradrenaline (NA) and/or its agonists and antagonists. Ejection of NA-modified excitatory responses mediated by NMDA receptors (NMDAR) in all neurons tested; the effect was enhancement in 59% of cases and depression in the remaining 41%. Enhancements prevailed in all VN with the exception of the lateral vestibular nucleus, where both effects were recorded in an equal number of cases. The enhancing action of NA on NMDAR-mediated responses was mimicked by the noradrenergic beta-receptor agonist isoproterenol, the beta1 specific agonist denopamine and the alpha2 agonist clonidine. These effects were blocked respectively by the generic beta-receptor antagonist timolol, the beta1 antagonist atenolol and the alpha2 antagonist yohimbine. In contrast, application of the alpha1 receptor agonist cirazoline and the specific alpha1 antagonist prazosin respectively mimicked and partially antagonized the depression of NMDAR-mediated excitations induced by NA. Double-labeling immunohistochemical techniques demonstrated broad colocalization of NMDAR (specifically NR1 and NR2 subunits) with noradrenergic receptors (alpha1, alpha2 and beta1) in many VN neurons; only minor differences were found between nuclei. These results indicate that NA can produce generalized modulation of NMDAR-mediated excitatory neurotransmission in VN, which may in turn modify synaptic plasticity within the nuclei. PMID:24508745

Barresi, M; Grasso, C; Licata, F; Li Volsi, G

2014-04-18

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ACTIVITY OF THE INFERIOR VESTIBULAR NUCLEI NEURONS BY STIMULATION OF HYPOTHALAMIC PARAVENTRICULAR AND SUPRAOPTIC NUCLEI IN CONDITIONS OF UNILATERAL LABYRINTHECTOMY COMBINED WITH VIBRATION EXPOSURE  

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Full Text Available We have performed the programmed analysis of changes of frequency of single neuronal spike activity flow of inferior vestibular nucleus (IVN of rats, evoked by high frequency stimulation (HFS of paraventricular (PVN and supraoptic nuclei (SON of hypothalamus in conditions of unilateral labyrinthectomy (UL combined with multi-day vibration exposure (VE. In neurons of the uninjured side of the IVN HFS PVN and SON dominate inhibitory responses (84.50% and 75.80%, respectively, on the affected side also predominate inhibitory responses (55.10% and 48.80% respectively, along with excitatory (28,20% and 43.50% respectively. It is assumed that the dominance of GABAergic effects contribute to vestibular compensation after UL. The results of the morphological and histochemical study confirm the neuroprotective role of VE in condition of UL.

S.H. Sarkisyan

2012-02-01

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Modelling the firing pattern of bullfrog vestibular neurons responding to naturalistic stimuli  

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We have developed a neural system identification method for fitting models to stimulus-response data, where the response is a spike train. The method involves using a general nonlinear optimisation procedure to fit models in the time domain. We have applied the method to model bullfrog semicircular canal afferent neuron responses during naturalistic, broad-band head rotations. These neurons respond in diverse ways, but a simple four parameter class of models elegantly accounts for the various types of responses observed. c1999 Elsevier Science B.V. All rights reserved.

Paulin, M. G.; Hoffman, L. F.

1999-01-01

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Implantes vestibulares / Vestibular prosthesis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish La lesión o hipofunción vestibular bilateral (HVB) es un cuadro clínico que provoca oscilopsias y desequilibrio incapacitante que se agrava en oscuridad. Algunas de las causas de HVB son el uso de drogas ototóxicas, enfermedad de Ménière bilateral, enfermedades autoinmunes y degeneración espinocereb [...] elar. El manejo de esta discapacidad es complejo y muchas veces la rehabilitación no logra los objetivos deseados. Una de las alternativas terapéuticas futuras para la HVB y aún en plena fase experimental es el implante vestibular, cuyo funcionamiento en términos generales es similar al de un implante coclear. En esta revisión se analiza la génesis e historia del desarrollo de los implantes vestibulares, sus principales características y el futuro de su implementación. Abstract in english Bilateral vestibular loss (BVL) is a clinic syndrome that produces oscillopsias and disabling disequilibrium, especially in darkness. Some causes of BVL are the use of ototoxic drugs, bilateral Ménière disease, autoinmune ear disorders and spinocerebellar ataxia. The management of this disability is [...] complex and many times the rehabilitation does not accomplish with the desired goals. One future therapeutic alternative for BVL and still in an experimental stage is the vestibular implant, whose overall functioning is similar to a cochlear implant. In this review we analyze the genesis and history of vestibular implant development, its main technical characteristics and the future of its implementation.

Cristian, Aedo Sánchez; Paul H, Délano Reyes.

2013-12-01

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Implantes vestibulares / Vestibular prosthesis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish La lesión o hipofunción vestibular bilateral (HVB) es un cuadro clínico que provoca oscilopsias y desequilibrio incapacitante que se agrava en oscuridad. Algunas de las causas de HVB son el uso de drogas ototóxicas, enfermedad de Ménière bilateral, enfermedades autoinmunes y degeneración espinocereb [...] elar. El manejo de esta discapacidad es complejo y muchas veces la rehabilitación no logra los objetivos deseados. Una de las alternativas terapéuticas futuras para la HVB y aún en plena fase experimental es el implante vestibular, cuyo funcionamiento en términos generales es similar al de un implante coclear. En esta revisión se analiza la génesis e historia del desarrollo de los implantes vestibulares, sus principales características y el futuro de su implementación. Abstract in english Bilateral vestibular loss (BVL) is a clinic syndrome that produces oscillopsias and disabling disequilibrium, especially in darkness. Some causes of BVL are the use of ototoxic drugs, bilateral Ménière disease, autoinmune ear disorders and spinocerebellar ataxia. The management of this disability is [...] complex and many times the rehabilitation does not accomplish with the desired goals. One future therapeutic alternative for BVL and still in an experimental stage is the vestibular implant, whose overall functioning is similar to a cochlear implant. In this review we analyze the genesis and history of vestibular implant development, its main technical characteristics and the future of its implementation.

Cristian, Aedo Sánchez; Paul H, Délano Reyes.

36

Integrative responses of neurons in parabrachial nuclei to a nauseogenic gastrointestinal stimulus and vestibular stimulation in vertical planes  

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The parabrachial and adjacent Kölliker-Fuse (PBN/KF) nuclei play a key role in relaying visceral afferent inputs to the hypothalamus and limbic system and are, thus, believed to participate in generating nausea and affective responses elicited by gastrointestinal (GI) signals. In addition, the PBN/KF region receives inputs from the vestibular system and likely mediates the malaise associated with motion sickness. However, previous studies have not considered whether GI and vestibular inputs ...

Suzuki, Takeshi; Sugiyama, Yoichiro; Yates, Bill J.

2012-01-01

37

Vestibular blueprint in early vertebrates  

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Full Text Available Central vestibular neurons form identifiable subgroups within the boundaries of classically outlined octavolateral nuclei in primitive vertebrates that are distinct from those processing lateral line, electrosensory and auditory signals. Each vestibular subgroup exhibits a particular morpho-physiological property that receives origin-specific sensory inputs from semicircular canal and otolith organs. Behaviorally characterized phenotypes send discrete axonal projections to extraocular, spinal and cerebellar targets including other ipsi- and contralateral vestibular nuclei. The anatomical locations of vestibuloocular and vestibulospinal neurons correlate with genetically defined hindbrain compartments that are well conserved throughout vertebrate evolution though some variability exists in fossil and extant vertebrate species. The different vestibular subgroups exhibit a robust sensorimotor signal processing complemented with a high degree of vestibular and visual adaptive plasticity.

HansStraka

2013-11-01

38

Activation of ?-opioid receptors inhibits calcium-currents in the vestibular afferent neurons of the rat through a cAMP dependent mechanism.  

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Opioid receptors are expressed in the vestibular endorgans (afferent neurons and hair cells) and are activated by the efferent system, which modulates the discharge of action potentials in vestibular afferent neurons (VANs). In mammals, VANs mainly express the ? opioid-receptor, but the function of this receptors activation and the cellular mechanisms by which they exert their actions in these neurons are poorly studied. To determine the actions of ? opioid receptor (MOR) and cell signaling mechanisms in VANs, we made perforated patch-clamp recordings of VANs that were obtained from postnatal days 7 to 10 (P7-10) rats and then maintained in primary culture. The MOR agonist [D-Ala(2), N-Me-Phe(4), Gly(5)-ol]-enkephalin (DAMGO) inhibited the total voltage-gated outward current; this effect was prevented by the perfusion of a Ca(2+)-free extracellular solution. We then studied the voltage-gated calcium current (Ica) and found that DAMGO Met-enkephalin or endomorphin-1 inhibited the ICa in a dose-response fashion. The effects of DAMGO were prevented by the MOR antagonist (CTAP) or by pertussis toxin (PTX). The use of specific calcium channel blockers showed that MOR activation inhibited T-, L- and N-type ICa. The use of various enzyme activators and inhibitors and of cAMP analogs allowed us to demonstrate that the MOR acts through a cAMP dependent signaling mechanism. In current clamp experiments, MOR activation increased the duration and decreased the amplitude of the action potentials and modulated the discharge produced by current injection. Pre-incubation with PTX occluded MOR activation effect. We conclude that MOR activation inhibits the T-, L- and N-type ICa through activation of a G?i/o protein that involves a decrease in AC-cAMP-PKA activity. The modulation of ICa may have an impact on the synaptic integration, excitability, and neurotransmitter release from VANs. PMID:24734002

Seseña, Emmanuel; Vega, Rosario; Soto, Enrique

2014-01-01

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ACTIVITY OF THE SUPERIOR VESTIBULAR NUCLEI NEURONS AT STIMULATION OF HYPOTHALAMIC PARAVENTRICULAR AND SUPRAOPTIC NUCLEI IN CONDITIONS OF UNILATERAL LABYRINTHECTOMY COMBINED WITH VIBRATION EXPOSURE  

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Full Text Available We studied the frequency changes of single neuronal spike activity flow from superior vestibular nucleus (SVN, evoked on high frequency stimulation (HFS of paraventricular (PV and supraoptic (SO nuclei of hypothalamus in Albino rats in conditions of unilateral labyrinthectomy (UL combined with many days of vibration exposure (VE. Programmed mathematical on-lin? analysis was used. In normal conditions, at bilateral stimulation of PV and SO nuclei the tetanic potentiation (TP prevaled. After UL in control at uninjured side TP and posttetanic potentiation (PTP were recorded; on injured side, on the whole, along with variability of initial background activity of SVN neurons, an exiguity of components and of the repeatability of poststimulus excitatory and inhibitory manifestations of SVN neurons’ activity were recorded. Combined action of UL and VE at intact side evoked tetanic depression on ipsilateral stimulation of PV and SO nuclei; on injured side the stimulation of the same nuclei evoked TP and PTP, which achieved normal levels. The results of histochemical investigation in analogous experimental conditions confirmed the electrophysiological data, which allowed us concluding about protective effect of VE.

S.H. Sarkisyan

2010-05-01

40

Activation of µ-opioid receptors inhibits calcium-currents in the vestibular afferent neurons of the rat through a cAMP dependent mechanism  

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Full Text Available Opioid receptors are expressed in the vestibular endorgans (afferent neurons and hair cells and are activated by the efferent system, which modulates the discharge of action potentials in the vestibular afferent neurons (VANs. In mammals, the VANs mainly express the µ opioid-receptor, but the function of the opioid receptor activation and the cellular mechanisms by which they exert their actions in these neurons are poorly studied. To determine the actions of the µ opioid receptor (MOR and the cell signaling mechanisms in the VANs, we made perforated patch-clamp recordings of VANs that were obtained from postnatal days 7 to 10 (P7-10 rats and then maintained in primary culture. The MOR agonist [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO inhibited the total voltage-gated outward current; this effect was prevented by the perfusion of a Ca2+-free extracellular solution. We then studied the voltage-gated calcium current (Ica and found that DAMGO Met-enkephalin or endomorphine-1 inhibited the ICa in a dose-response fashion. The effects of DAMGO were prevented by the MOR antagonist (CTAP or by the pertussis toxin (PTX. The use of specific calcium channel blockers showed that MOR activation inhibited the T-, L- and N-type ICa. The use of various enzyme activators and inhibitors and of cAMP analogs allowed us to demonstrate that the MOR acts through a cAMP dependent signaling mechanism. In the current clamp experiments, MOR activation increased the duration and decreased the amplitude of the action potentials and modulated the discharge to the current injection. Pre-incubation with PTX occluded all MOR activation effects observed in the current clamp experiments.\tWe conclude that MOR activation inhibits the T-, L- and N-type ICa through the activation of a G?i/o protein that involves a decrease in AC-cAMP-PKA activity. The modulation of ICa may have an impact on the synaptic integration, excitability and neurotransmitter release from the VANs.

Enrique Soto

2014-03-01

 
 
 
 
41

Towards a neuromorphic vestibular system.  

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The vestibular system plays a crucial role in the sense of balance and spatial orientation in mammals. It is a sensory system that detects both rotational and translational motion of the head, via its semicircular canals and otoliths respectively. In this work, we propose a real-time hardware model of an artificial vestibular system, implemented using a custom neuromorphic Very Large Scale Integration (VLSI) multi-neuron chip interfaced to a commercial Inertial Measurement Unit (IMU). The artificial vestibular system is realized with spiking neurons that reproduce the responses of biological hair cells present in the real semicircular canals and otholitic organs. We demonstrate the real-time performance of the hybrid analog-digital system and characterize its response properties, presenting measurements of a successful encoding of angular velocities as well as linear accelerations. As an application, we realized a novel implementation of a recurrent integrator network capable of keeping track of the current angular position. The experimental results provided validate the hardware implementation via comparisons with a detailed computational neuroscience model. In addition to being an ideal tool for developing bio-inspired robotic technologies, this work provides a basis for developing a complete low-power neuromorphic vestibular system which integrates the hardware model of the neural signal processing pathway described with custom bio-mimetic gyroscopic sensors, exploiting neuromorphic principles in both mechanical and electronic aspects. PMID:25314706

Corradi, Federico; Zambrano, Davide; Raglianti, Marco; Passetti, Giovanni; Laschi, Cecilia; Indiveri, Giacomo

2014-10-01

42

Procedures for restoring vestibular disorders  

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Full Text Available This paper will discuss therapeutic possibilities for disorders of the vestibular organs and the neurons involved, which confront ENT clinicians in everyday practice. Treatment of such disorders can be tackled either symptomatically or causally. The possible strategies for restoring the body's vestibular sense, visual function and co-ordination include medication, as well as physical and surgical procedures. Prophylactic or preventive measures are possible in some disorders which involve vertigo (bilateral vestibulopathy, kinetosis, height vertigo, vestibular disorders when diving (Tables 1 and 2. Glucocorticoid and training therapy encourage the compensation of unilateral vestibular loss. In the case of a bilateral vestibular loss, it is important to treat the underlying disease (e.g. Cogan's disease. Although balance training does improve the patient's sense of balance, it will not restore it completely.In the case of Meniere's disease, there are a number of medications available to either treat bouts or to act as a prophylactic (e.g. dimenhydrinate or betahistine. In addition, there are non-ablative (sacculotomy as well as ablative surgical procedures (e.g. labyrinthectomy, neurectomy of the vestibular nerve. In everyday practice, it has become common to proceed with low risk therapies initially. The physical treatment of mild postural vertigo can be carried out quickly and easily in outpatients (repositioning or liberatory maneuvers. In very rare cases it may be necessary to carry out a semicircular canal occlusion. Isolated disturbances of the otolith function or an involvement of the otolith can be found in roughly 50% of labyrinth disturbances. A specific surgical procedure to selectively block the otolith organs is currently being studied. When an external perilymph fistula involving loss of perilymph is suspected, an exploratory tympanotomy involving also the round and oval window niches must be carried out. A traumatic rupture of the round window membrane can, for example, also be caused by an implosive inner ear barotrauma during the decompression phase of diving. Dehiscence of the anterior semicircular canal, a relatively rare disorder, can be treated conservatively (avoiding stimuli which cause dizziness, by non-ablative „resurfacing" or by „plugging" the semicircular canal. A perilymph fistula can cause a Tullio-phenomenon resulting from a traumatic dislocation or hypermobility of the stapes, which can be surgically corrected. Vestibular disorders can also result from otosurgical therapy. When balance disorders persist following stapedectomy it is necessary to carry out a revision operation in order to either exclude a perilymph fistula or shorten the piston. Surgically reducing the size of open mastoid cavities (using for example porous hydroxylapatite or cartilage can result in a reduction of vertiginous symptoms while nursing or during exposure to ambient air. Vestibular disturbances can occur both before and after vestibular nerve surgery (acoustic neuroma. Initially, good vestibular compensation can be expected after surgically removing the acoustic neuroma. An aberrant regeneration of nerve fibers of the vestibulocochlear nerve has been suggested as a cause for secondary worsening. Episodes of vertigo can be caused by an irritation of the vestibular nerve (vascular loop. Neurovascular decompression is generally regarded as the best surgical therapy. In the elderly, vestibular disturbances can severely limit quality of life and are often aggravated by multiple comorbidities. Antivertiginous drugs (e.g. dimenhydrinate in combination with movement training can significantly reduce symptoms. Administering antivertiginous drugs over varying periods of time (e.g. transdermal scopolamine application via patches as well as kinetosis training can be used as both prophylactically and as a therapy for kinetosis. Exposure training should be used as a prophylactic for height vertigo.

Walther, Leif Erik

2005-09-01

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Diverse spatial reference frames of vestibular signals in parietal cortex.  

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Reference frames are important for understanding how sensory cues from different modalities are coordinated to guide behavior, and the parietal cortex is critical to these functions. We compare reference frames of vestibular self-motion signals in the ventral intraparietal area (VIP), parietoinsular vestibular cortex (PIVC), and dorsal medial superior temporal area (MSTd). Vestibular heading tuning in VIP is invariant to changes in both eye and head positions, indicating a body (or world)-centered reference frame. Vestibular signals in PIVC have reference frames that are intermediate between head and body centered. In contrast, MSTd neurons show reference frames between head and eye centered but not body centered. Eye and head position gain fields were strongest in MSTd and weakest in PIVC. Our findings reveal distinct spatial reference frames for representing vestibular signals and pose new challenges for understanding the respective roles of these areas in potentially diverse vestibular functions. PMID:24239126

Chen, Xiaodong; Deangelis, Gregory C; Angelaki, Dora E

2013-12-01

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Large vestibular aqueduct syndrome.  

Science.gov (United States)

Large Vestibular Aqueduct Syndrome is a congenital malformation of the temporal bone characterised by early onset of sensorineural hearing loss and vestibular disturbance. Familial large vestibular aqueduct syndrome suggests autosomal recessive or X-linked inheritance and accounts for non-syndromic sensorineural hearing loss in these patients. PMID:16570713

Dipak, S; Prepageran, N; Sazila, A S; Rahmat, O; Raman, R

2005-10-01

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Vestibular migraine : Diagnostic criteria  

DEFF Research Database (Denmark)

This paper presents diagnostic criteria for vestibular migraine, jointly formulated by the Committee for Classification of Vestibular Disorders of the Bárány Society and the Migraine Classification Subcommittee of the International Headache Society (IHS). The classification includes vestibular migraine and probable vestibular migraine. Vestibular migraine will appear in an appendix of the third edition of the International Classification of Headache Disorders (ICHD) as a first step for new entities, in accordance with the usual IHS procedures. Probable vestibular migraine may be included in a later version of the ICHD, when further evidence has been accumulated. The diagnosis of vestibular migraine is based on recurrent vestibular symptoms, a history of migraine, a temporal association between vestibular symptoms and migraine symptoms and exclusion of other causes of vestibular symptoms. Symptoms that qualify for a diagnosis of vestibular migraine include various types of vertigo as well as head motion-induced dizziness with nausea. Symptoms must be of moderate or severe intensity. Duration of acute episodes is limited to a window of between 5 minutes and 72 hours.

Lempert, Thomas; Olesen, Jes

2012-01-01

46

Direction specific biases in human visual and vestibular heading perception.  

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Heading direction is determined from visual and vestibular cues. Both sensory modalities have been shown to have better direction discrimination for headings near straight ahead. Previous studies of visual heading estimation have not used the full range of stimuli, and vestibular heading estimation has not previously been reported. The current experiments measure human heading estimation in the horizontal plane to vestibular, visual, and spoken stimuli. The vestibular and visual tasks involved 16 cm of platform or visual motion. The spoken stimulus was a voice command speaking a heading angle. All conditions demonstrated direction dependent biases in perceived headings such that biases increased with headings further from the fore-aft axis. The bias was larger with the visual stimulus when compared with the vestibular stimulus in all 10 subjects. For the visual and vestibular tasks precision was best for headings near fore-aft. The spoken headings had the least bias, and the variation in precision was less dependent on direction. In a separate experiment when headings were limited to ± 45°, the biases were much less, demonstrating the range of headings influences perception. There was a strong and highly significant correlation between the bias curves for visual and spoken stimuli in every subject. The correlation between visual-vestibular and vestibular-spoken biases were weaker but remained significant. The observed biases in both visual and vestibular heading perception qualitatively resembled predictions of a recent population vector decoder model (Gu et al., 2010) based on the known distribution of neuronal sensitivities. PMID:23236490

Crane, Benjamin T

2012-01-01

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How actions alter sensory processing: reafference in the vestibular system.  

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Our vestibular organs are simultaneously activated by our own actions as well as by stimulation from the external world. The ability to distinguish sensory inputs that are a consequence of our own actions (vestibular reafference) from those that result from changes in the external world (vestibular exafference) is essential for perceptual stability and accurate motor control. Recent work in our laboratory has focused on understanding how the brain distinguishes between vestibular reafference and exafference. Single-unit recordings were made in alert rhesus monkeys during passive and voluntary (i.e., active) head movements. We found that neurons in the first central stage of vestibular processing (vestibular nuclei), but not the primary vestibular afferents, can distinguish between active and passive movements. In order to better understand how neurons differentiate active from passive head motion, we systematically tested neuronal responses to different combinations of passive and active motion resulting from rotation of the head-on-body and/or head-and-body in space. We found that during active movements, a cancellation signal was generated when the activation of proprioceptors matched the motor-generated expectation. PMID:19645877

Cullen, Kathleen E; Brooks, Jessica X; Sadeghi, Soroush G

2009-05-01

48

A vestibular sensation: probabilistic approaches to spatial perception  

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The vestibular system helps maintain equilibrium and clear vision through reflexes, but it also contributes to spatial perception. In recent years, research in the vestibular field has expanded to higher level processing involving the cortex. Vestibular contributions to spatial cognition have been difficult to study because the circuits involved are inherently multisensory. Computational methods and the application of Bayes theorem are used to form hypotheses about how information from different sensory modalities is combined together with expectations based on past experience in order to obtain optimal estimates of cognitive variables like current spatial orientation. To test these hypotheses, neuronal populations are being recorded during active tasks in which subjects make decisions based on vestibular and visual or somatosensory information. This review highlights what is currently known about the role of vestibular information in these processes, the computations necessary to obtain the appropriate signals, and the benefits that have emerged thus far. PMID:19945388

Angelaki, Dora E.; Klier, Eliana M.; Snyder, Lawrence H.

2009-01-01

49

Vestibular perception following acute unilateral vestibular lesions.  

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Little is known about the vestibulo-perceptual (VP) system, particularly after a unilateral vestibular lesion. We investigated vestibulo-ocular (VO) and VP function in 25 patients with vestibular neuritis (VN) acutely (2 days after onset) and after compensation (recovery phase, 10 weeks). Since the effect of VN on reflex and perceptual function may differ at threshold and supra-threshold acceleration levels, we used two stimulus intensities, acceleration steps of 0.5°/s(2) and velocity steps of 90°/s (acceleration 180°/s(2)). We hypothesised that the vestibular lesion or the compensatory processes could dissociate VO and VP function, particularly if the acute vertiginous sensation interferes with the perceptual tasks. Both in acute and recovery phases, VO and VP thresholds increased, particularly during ipsilesional rotations. In signal detection theory this indicates that signals from the healthy and affected side are still fused, but result in asymmetric thresholds due to a lesion-induced bias. The normal pattern whereby VP thresholds are higher than VO thresholds was preserved, indicating that any 'perceptual noise' added by the vertigo does not disrupt the cognitive decision-making processes inherent to the perceptual task. Overall, the parallel findings in VO and VP thresholds imply little or no additional cortical processing and suggest that vestibular thresholds essentially reflect the sensitivity of the fused peripheral receptors. In contrast, a significant VO-VP dissociation for supra-threshold stimuli was found. Acutely, time constants and duration of the VO and VP responses were reduced - asymmetrically for VO, as expected, but surprisingly symmetrical for perception. At recovery, VP responses normalised but VO responses remained shortened and asymmetric. Thus, unlike threshold data, supra-threshold responses show considerable VO-VP dissociation indicative of additional, higher-order processing of vestibular signals. We provide evidence of perceptual processes (ultimately cortical) participating in vestibular compensation, suppressing asymmetry acutely in unilateral vestibular lesions. PMID:23671577

Cousins, Sian; Kaski, Diego; Cutfield, Nicholas; Seemungal, Barry; Golding, John F; Gresty, Michael; Glasauer, Stefan; Bronstein, Adolfo M

2013-01-01

50

ISOLATION AND CHARACTERIZATION OF VESTIBULAR STEM CELLS  

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Full Text Available Introduction The purpose of the ongoing research is to improve our current skills and knowledge in stem cell isolation, cultivation and differentiation from the vestibular epithelia of young mice. Matherials and Methods We harvested utricles and sacculi from 7 days old mice. Obtained cells were cultivated at 37ºC and 5% CO2 in DMEM with F12 Nutrient mixture, B27, N2 supplement, IGF-1 and EGF. Sphere pluripotency was established with Nanog and Oct-4 stem cell markers. We mechanically dissociated primary spheres and cultivated them. Cells were characterized by immunofluorescence and immunohistochemistry for myosinVIIA (hair cell marker, nestin (intermediate filament VI marker and beta III tubulin. Results We proved that vestibular epithelia contains pluripotent stem cells which formed spheres. Sphere-derived cells’ pluripotency was demonstrated by the expression of nanog, oct 4 and nestin markers. We obtained through differentiation different cell types including neuronal cells which were positive for myosin VIIA, nestin, beta III tubulin. We wanted to know the type of neurons and performed Brn3a staining for immature neurons, and  TrKB staining for mature neurons. We cultivated vestibular stem cells on different substrates to observe their behavior. Conclusions Cells obtained from utricular epithelia are pluripotent because they express nanog, oct 4,  nestin, characteristic for cell progenitors and they generate spheres.

Roxana Daniela Vintila

2013-10-01

51

Vestibular evoked myogenic potential  

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Full Text Available Introduction: The Vestibular Evoked Myogenic Potential (VEMP is a promising test for the evaluation of the cholic descending vestibular system. This reflex depends of the integrity from the saccular macula, from the inferior vestibular nerve, the vestibular nuclei, the vestibule-spinal tract and effectors muscles. Objective: Perform a systematic review of the pertinent literature by means of database (COCHRANE, MEDLINE, LILACS, CAPES. Conclusion: The clinical application of the VEMP has expanded in the last years, as goal that this exam is used as complementary in the otoneurological evaluation currently used. But, methodological issues must be clarified. This way, this method when combined with the standard protocol, can provide a more widely evaluation from the vestibular system. The standardization of the methodology is fundamental criterion for the replicability and sensibility of the exam.

Felipe, Lilian

2012-01-01

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Deregulated genes in sporadic vestibular schwannomas  

DEFF Research Database (Denmark)

In search of genes associated with vestibular schwannoma tumorigenesis, this study examines the gene expression in human vestibular nerve versus vestibular schwannoma tissue samples using microarray technology.

Cayé-Thomasen, Per; Helweg-Larsen, Rehannah Holga Andrea

2010-01-01

53

Vestibular effects of lidocaine intratympanic injection in rats.  

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When lidocaine is locally delivered into the inner ear, it rapidly paralyzes the peripheral vestibular afferent neurons and induces unilateral vestibular loss. The goals of this study were to explore the possibility of developing intratympanic injection (IT) of lidocaine as a modality for treating acute vertigo. To evaluate the minimum concentration required, latent time, action duration, and possibility of lidocaine IT readministration to the vestibular system, we compared the development of horizontal nystagmus after IT of 2, 4, 6, 8, and 10% lidocaine solutions in rats. To identify the induction of vestibular compensation, c-Fos-like protein expression was observed in the vestibular nucleus. Results of our investigation showed that lidocaine IT concentrations greater than 4% induced vestibular hyporeflexia in the injected ear. In order to induce hyporeflexia 4 and 6% lidocaine solutions could also be repeatedly injected. Regardless of concentration, effects of the lidocaine IT dissipated gradually over time. Our findings could be used to develop novel methods for symptom control in vestibular disorder patients. PMID:24505049

Lee, Hh; Kim, Mj; Jo, Yk; Kim, Jy; Han, Gc

2014-11-01

54

Vestibular Schwannoma (Acoustic Neuroma) and Neurofibromatosis  

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... Vestibular Schwannoma (Acoustic Neuroma) and Neurofibromatosis Vestibular Schwannoma (Acoustic Neuroma) and Neurofibromatosis On this page: What is a ... get additional information? What is a vestibular schwannoma (acoustic neuroma)? A vestibular schwannoma (also known as acoustic neuroma , ...

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Vestibular function testing.  

LENUS (Irish Health Repository)

Vestibular symptoms of vertigo, dizziness and dysequilibrium are common complaints which can be disabling both physically and psychologically. Routine examination of the ear nose and throat and neurological system are often normal in these patients. An accurate history and thorough clinical examination can provide a diagnosis in the majority of patients. However, in a subgroup of patients, vestibular function testing may be invaluable in arriving at a correct diagnosis and ultimately in the optimal treatment of these patients.

Lang, E E

2010-06-01

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Organization of projections from the raphe nuclei to the vestibular nuclei in rats  

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Previous anatomic and electrophysiological evidence suggests that serotonin modulates processing in the vestibular nuclei. This study examined the organization of projections from serotonergic raphe nuclei to the vestibular nuclei in rats. The distribution of serotonergic axons in the vestibular nuclei was visualized immunohistochemically in rat brain slices using antisera directed against the serotonin transporter. The density of serotonin transporter-immunopositive fibers is greatest in the superior vestibular nucleus and the medial vestibular nucleus, especially along the border of the fourth ventricle; it declines in more lateral and caudal regions of the vestibular nuclear complex. After unilateral iontophoretic injections of Fluoro-Gold into the vestibular nuclei, retrogradely labeled neurons were found in the dorsal raphe nucleus (including the dorsomedial, ventromedial and lateral subdivisions) and nucleus raphe obscurus, and to a minor extent in nucleus raphe pallidus and nucleus raphe magnus. The combination of retrograde tracing with serotonin immunohistofluorescence in additional experiments revealed that the vestibular nuclei receive both serotonergic and non-serotonergic projections from raphe nuclei. Tracer injections in densely innervated regions (especially the medial and superior vestibular nuclei) were associated with the largest numbers of Fluoro-Gold-labeled cells. Differences were observed in the termination patterns of projections from the individual raphe nuclei. Thus, the dorsal raphe nucleus sends projections that terminate predominantly in the rostral and medial aspects of the vestibular nuclear complex, while nucleus raphe obscurus projects relatively uniformly throughout the vestibular nuclei. Based on the topographical organization of raphe input to the vestibular nuclei, it appears that dense projections from raphe nuclei are colocalized with terminal fields of flocculo-nodular lobe and uvula Purkinje cells. It is hypothesized that raphe-vestibular connections are organized to selectively modulate processing in regions of the vestibular nuclear complex that receive input from specific cerebellar zones. This represents a potential mechanism whereby motor activity and behavioral arousal could influence the activity of cerebellovestibular circuits.

Halberstadt, A. L.; Balaban, C. D.

2003-01-01

57

Spatial and temporal characteristics of vestibular convergence.  

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In all species studied, afferents from semicircular canals and otolith organs converge on central neurons in the brainstem. However, the spatial and temporal relationships between converging inputs and how these contribute to vestibular behaviors is not well understood. In the current study, we used discrete rotational and translational motion stimuli to characterize canal- and otolith-driven response components of convergent non-eye movement (NEM) neurons in the vestibular nuclear complex of alert pigeons. When compared to afferent responses, convergent canal signals had similar gain and phase ranges but exhibited greater spatial variability in their axes of preferred rotation. Convergent otolith signals also had similar mean gain and phase values to the afferent population but were spatially well-matched with the corresponding canal signals, cell-by-cell. However, neither response component alone nor a simple linear combination of these components was sufficient to predict actual net responses during combined canal-otolith stimulation. We discuss these findings in the context of previous studies of pigeon vestibular behaviors, and we compare our findings to similar studies in other species. PMID:21756981

McArthur, K L; Zakir, M; Haque, A; Dickman, J D

2011-09-29

58

Positive Habituation and Vestibular Recruitment.  

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Adaptation and sensory stimulation as it applied to the vestibular apparatus are discussed. Multiple rotatory, thermal, galvanic and pendular stimuli do not result in habituation. The peripheral vestibular receptor always reacts in the same manner followi...

M. Emami-nouri

1974-01-01

59

Inferior vestibular neuritis.  

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Vestibular neuritis (VN) mostly involves the superior portion of the vestibular nerve and labyrinth. This study aimed to describe the clinical features of VN involving the inferior vestibular labyrinth and its afferents only. Of the 703 patients with a diagnosis of VN or labyrinthitis at Seoul National University Bundang Hospital from 2004 to 2010, we retrospectively recruited 9 patients (6 women, age range 15-75) with a diagnosis of isolated inferior VN. Diagnosis of isolated inferior VN was based on torsional downbeating spontaneous nystagmus, abnormal head-impulse test (HIT) for the posterior semicircular canal (PC), and abnormal cervical vestibular-evoked myogenic potentials (VEMP) in the presence of normally functioning horizontal and anterior semicircular canals, as determined by normal HIT and bithermal caloric tests. All patients presented with acute vertigo with nausea, vomiting, and imbalance. Three patients also had tinnitus and hearing loss in the involved side. The rotation axis of torsional downbeating spontaneous nystagmus was best aligned with that of the involved PC. HIT was also positive only for the involved PC. Cervical VEMP was abnormal in seven patients, and ocular VEMP was normal in all four patients tested. Ocular torsion and subjective visual vertical tests were mostly within the normal range. Since isolated inferior VN lacks the typical findings of much more prevalent superior VN, it may be mistaken for a central vestibular disorder. Recognition of this rare disorder may help avoid unnecessary workups in patients with acute vestibulopathy. PMID:22215238

Kim, Ji-Soo; Kim, Hyo Jung

2012-08-01

60

Vestibular activity and cognitive development in children: perspectives.  

Science.gov (United States)

Vestibular signals play an essential role in oculomotor and static and dynamic posturomotor functions. Increasing attention is now focusing on their impact on spatial and non-spatial cognitive functions. Movements of the head in space evoke vestibular signals that make important contributions during the development of brain representations of body parts relative to one another as well as representations of body orientation and position within the environment. A central nervous system pathway relays signals from the vestibular nuclei to the hippocampal system where this input is indispensable for neuronal responses selective for the position and orientation of the head in space. One aspect of the hippocampal systems' processing to create episodic and contextual memories is its role in spatial orientation and navigation behaviors that require processing of relations between background cues. These are also impaired in adult patients with vestibular deficits. However little is known about the impact of vestibular loss on cognitive development in children. This is investigated here with a particular emphasis upon the hypothetical mechanisms and potential impact of vestibular loss at critical ages on the development of respective spatial and non-spatial cognitive processes and their brain substrates. PMID:24376403

Wiener-Vacher, Sylvette R; Hamilton, Derek A; Wiener, Sidney I

2013-01-01

 
 
 
 
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Vestibular activity and cognitive development in children: Perspectives  

Directory of Open Access Journals (Sweden)

Full Text Available Vestibular signals play an essential role in oculomotor and static and dynamic posturomotor functions. Increasing attention is now focusing on their impact on spatial and non-spatial cognitive functions. Movements of the head in space evoke vestibular signals that make important contributions during the development of brain representations of body parts relative to one another as well as representations of body orientation and position within the environment. A central nervous system pathway relays signals from the vestibular nuclei to the hippocampus where this input is indispensable for neuronal responses selective for the position and orientation of the head in space. One aspect of hippocampal systems' processing to create episodic and contextual memories is its role in spatial orientation and navigation behaviors that require processing of relations between background cues. These are also impaired in adult patients with vestibular deficits, however little is known about the impact of vestibular loss on cognitive development in children. This is investigated here with a particular emphasis upon the hypothetical mechanisms and potential impact of vestibular loss at critical ages on the development of respective spatial and non-spatial cognitive processes and their brain substrates.

SidneyIWiener

2013-12-01

62

Vestibular-Ocular Reflex  

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In this activity, learners will perform various investigations to understand the vestibular-ocular reflex and learn about the importance of visual cues in maintaining balance. During the two-part activity, learners will compare the stability of a moving image under two conditions as well as compare the effects of rotation on the sensation of spinning under varying conditions. This lesson guide includes background information, review and critical thinking questions with answers, and handouts. Educators can also use this activity to discuss how the brain functions in space and how researchers study the vestibular function in space.

Marlene Y. Macleish, Ed D.; Bernice R. Mclean, M. E.

2013-01-30

63

Labyrinthitis and Vestibular Neuritis  

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... shingles), influenza, measles, rubella, mumps, polio, hepatitis, and Epstein-Barr. Other viruses may be involved that are as yet unidentified ... people are completely free of symptoms. Others have chronic dizziness if the virus has damaged the vestibular nerve. Many people with ...

64

Vestibular function in the space environment  

Science.gov (United States)

The present work presents new results about the interdependence of optical illusory sensations and eye movements in man. To establish to what degree certain illusions previously obtained during centrifugation and parabolic flight can be explained by eye movements and by neuronal integration in the brain, real eye movements were measured as they occurred in the dark without optical fixation, during rectilinear accelerations on the ground, and during weightlessness in parabolic flight. Results provide valuable insight into normal vestibular function as well as resolution of within-the-eye and behind-the-eye contributions to the above illusions.

Von Baumgarten, R. J.; Harth, O.; Thuemler, R.; Baldrighi, G.; Shillinger, G. L., Jr.

1975-01-01

65

Central Vestibular Dysfunction in an Otorhinolaryngological Vestibular Unit: Incidence and Diagnostic Strategy  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction Vertigo can be due to a variety of central and peripheral causes. The relative incidence of central causes is underestimated. This may have an important impact of the patients' management and prognosis. Objective The objective of this work is to determine the incidence of central ves [...] tibular disorders in patients presenting to a vestibular unit in a tertiary referral academic center. It also aims at determining the best strategy to increase the diagnostic yield of the patients' visit. Methods This is a prospective observational study on 100 consecutive patients with symptoms suggestive of vestibular dysfunction. All patients completed a structured questionnaire and received bedside and vestibular examination and neuroimaging as required. Results There were 69 women and 31 men. Their ages ranged between 28 and 73 (mean 42.48 years). Provisional videonystagmography (VNG) results were: 40% benign paroxysmal positional vertigo (BPPV), 23% suspicious of central causes, 18% undiagnosed, 15% Meniere disease, and 4% vestibular neuronitis. Patients with an unclear diagnosis or central features (41) had magnetic resonance imaging (MRI) and Doppler studies. Combining data from history, VNG, and imaging studies, 23 patients (23%) were diagnosed as having a central vestibular lesion (10 with generalized ischemia/vertebra basilar insufficiency, 4 with multiple sclerosis, 4 with migraine vestibulopathy, 4 with phobic postural vertigo, and 1 with hyperventilation-induced nystagmus). Conclusions Combining a careful history with clinical examination, VNG, MRI, and Doppler studies decreases the number of undiagnosed cases and increases the detection of possible central lesions.

Badr E., Mostafa; Ayman O. El, Kahky; Hisham M. Abdel, Kader; Michael, Rizk.

2014-09-01

66

Central Vestibular Dysfunction in an Otorhinolaryngological Vestibular Unit: Incidence and Diagnostic Strategy  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction Vertigo can be due to a variety of central and peripheral causes. The relative incidence of central causes is underestimated. This may have an important impact of the patients' management and prognosis. Objective The objective of this work is to determine the incidence of central ves [...] tibular disorders in patients presenting to a vestibular unit in a tertiary referral academic center. It also aims at determining the best strategy to increase the diagnostic yield of the patients' visit. Methods This is a prospective observational study on 100 consecutive patients with symptoms suggestive of vestibular dysfunction. All patients completed a structured questionnaire and received bedside and vestibular examination and neuroimaging as required. Results There were 69 women and 31 men. Their ages ranged between 28 and 73 (mean 42.48 years). Provisional videonystagmography (VNG) results were: 40% benign paroxysmal positional vertigo (BPPV), 23% suspicious of central causes, 18% undiagnosed, 15% Meniere disease, and 4% vestibular neuronitis. Patients with an unclear diagnosis or central features (41) had magnetic resonance imaging (MRI) and Doppler studies. Combining data from history, VNG, and imaging studies, 23 patients (23%) were diagnosed as having a central vestibular lesion (10 with generalized ischemia/vertebra basilar insufficiency, 4 with multiple sclerosis, 4 with migraine vestibulopathy, 4 with phobic postural vertigo, and 1 with hyperventilation-induced nystagmus). Conclusions Combining a careful history with clinical examination, VNG, MRI, and Doppler studies decreases the number of undiagnosed cases and increases the detection of possible central lesions.

Badr E., Mostafa; Ayman O. El, Kahky; Hisham M. Abdel, Kader; Michael, Rizk.

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Spatial Cognition, Body Representation and Affective Processes: The Role of Vestibular Information beyond Ocular Reflexes and Control of Posture  

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Full Text Available A growing number of studies in humans demonstrate the involvement of vestibular information in tasks that are seemingly remote from well-known functions such as space constancy or postural control. In this review article we point out three emerging streams of research highlighting the importance of vestibular input: 1 Spatial Cognition: Modulation of vestibular signals can induce specific changes in spatial cognitive tasks like mental imagery and the processing of numbers. This has been shown in studies manipulating body orientation (changing the input from the otoliths, body rotation (changing the input from the semicircular canals, in clinical findings with vestibular patients, and in studies carried out in microgravity. There is also an effect in the reverse direction; top-down processes can affect perception of vestibular stimuli. 2 Body Representation: Numerous studies demonstrate that vestibular stimulation changes the representation of body parts, and sensitivity to tactile input or pain. Thus, the vestibular system plays an integral role in multisensory coordination of body representation. 3 Affective Processes and Disorders: Studies in psychiatric patients and patients with a vestibular disorder report a high comorbidity of vestibular dysfunctions and psychiatric symptoms. Recent studies investigated the beneficial effect of vestibular stimulation on psychiatric disorders, and how vestibular input can change mood and affect. These three emerging streams of research in vestibular science are – at least in part – associated with different neuronal core mechanisms. Spatial transformations draw on parietal areas, body representation is associated with somatosensory areas, and affective processes involve insular and cingulate cortices, all of which receive vestibular input. Even though a wide range of different vestibular cortical projection areas has been ascertained, their functionality still is scarcely understood.

Fred W Mast

2014-05-01

68

Audiologic diagnostics of vestibular schwannoma  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction Vestibular schwannoma (acoustic neuroma is a rare, but important cause of sensorineural hearing loss. Patients with asymmetric hearing loss, or unilateral tinnitus should be evaluated expeditiously, to prevent further neurological damage. Audiologic diagnostics Audiologic diagnostics represents the basic diagnosis for early detection of vestibular schwannoma. Patients with vestibular schwannomas may present with a variety of clinical features, including retrocochlear pattern of sensorineural hearing loss. Supraliminary audiometry, tympano- metry, stapedius reflex and otoacoustic emissions as well as vestibular response to caloric testing are methods for selection of patients with suspicion of this tumor. Conclusion The golden standard for audiologic diagnostics of vestibular schwannoma is BAEP (Brainstem Auditory Evoked Potentials. Patients with pathological findings of BAEP should undergo MRI of the posterior fossa. Gadolinium-enhanced magnetic resonance imaging is the best and final tool for making a diagnosis of vestibular schwannoma.

Komazec Zoran

2004-01-01

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Representation of vestibular and visual cues to self-motion in ventral intraparietal cortex.  

Science.gov (United States)

Convergence of vestibular and visual motion information is important for self-motion perception. One cortical area that combines vestibular and optic flow signals is the ventral intraparietal area (VIP). We characterized unisensory and multisensory responses of macaque VIP neurons to translations and rotations in three dimensions. Approximately one-half of VIP cells show significant directional selectivity in response to optic flow, one-half show tuning to vestibular stimuli, and one-third show multisensory responses. Visual and vestibular direction preferences of multisensory VIP neurons could be congruent or opposite. When visual and vestibular stimuli were combined, VIP responses could be dominated by either input, unlike the medial superior temporal area (MSTd) where optic flow tuning typically dominates or the visual posterior sylvian area (VPS) where vestibular tuning dominates. Optic flow selectivity in VIP was weaker than in MSTd but stronger than in VPS. In contrast, vestibular tuning for translation was strongest in VPS, intermediate in VIP, and weakest in MSTd. To characterize response dynamics, direction-time data were fit with a spatiotemporal model in which temporal responses were modeled as weighted sums of velocity, acceleration, and position components. Vestibular responses in VIP reflected balanced contributions of velocity and acceleration, whereas visual responses were dominated by velocity. Timing of vestibular responses in VIP was significantly faster than in MSTd, whereas timing of optic flow responses did not differ significantly among areas. These findings suggest that VIP may be proximal to MSTd in terms of vestibular processing but hierarchically similar to MSTd in terms of optic flow processing. PMID:21849564

Chen, Aihua; DeAngelis, Gregory C; Angelaki, Dora E

2011-08-17

70

Regeneration of vestibular horizontal semicircular canal afferents in pigeons.  

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Spontaneous regeneration of vestibular and auditory receptors and their innervating afferents in birds, reptiles, and amphibians are well known. Here, we produced a complete vestibular receptor loss and epithelial denervation using an ototoxic agent (streptomycin), after which we quantitatively characterized the afferent innervation of the horizontal semicircular canals following completed regeneration. We found that calyx, dimorph, and bouton afferents all regenerate in a manner the recapitulates the epithelial topography of normal birds, but over a slow time course. Similar to previous findings in the vestibular otolith maculae, regeneration occurs according to a three-stage temporal sequence. Bouton afferents regenerate during the first month of regeneration, followed by calyceal-bearing afferents in the second and third months. Calyx afferents were the last to regenerate in the final stage of recovery after 3 mo. We also found that regenerated afferents exhibited terminal morphologies that are significantly smaller, less complex, and innervate fewer receptor cells over smaller epithelial areas than those that develop through normative morphogenesis. These structural fiber changes in afferent innervation correlate to alterations in gaze responses during regeneration, although the exact underlying mechanisms responsible for behavioral changes remain unknown. Plasticity in central vestibular neurons processing motion information seem to be required to explain the observed morphologic and response adaptations observed in regenerating vestibular systems. PMID:19515948

Haque, Asim; Zakir, Mridha; Dickman, J David

2009-08-01

71

Development of neural correlates of linear motion in the rat vestibular nucleus.  

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The capability of the central vestibular system in utilizing cues arising from the inner ear determines the ability of animals to acquire the sense of head orientations in the three-dimensional space and to shape postural movements. During development, neurons in the vestibular nucleus (VN) show significant changes in their electrophysiological properties. An age-dependent enhancement of membrane excitability is accompanied by a progressive increase in firing rate and discharge regularity. The coding of horizontal and vertical linear motions also exhibits developmental refinement in VN neurons. Further, modification of cell surface receptors, such as glutamate receptors, of developing VN neurons are well-orchestrated in the course of maturation, thereby regulating synaptic efficacy and spatial coding capacity of these neurons in local circuits. Taken together, these characteristic features of VN neurons contribute to developmental establishment of space-centered coordinates within the brain. PMID:24553868

Ma, Chun-Wai; Lai, Chun-Hong; Han, Lei; De Nogueira Botelho, Francisco Paulo; Shum, Daisy Kwok-Yan; Chan, Ying-Shing

2014-02-25

72

5-HT(3) receptor expression in the mouse vestibular ganglion.  

Science.gov (United States)

The 5-hydroxytryptamine type 3 (5-HT3) receptor is a ligand-gated ion channel and a member of the Cys-loop family of receptors. Previous studies have shown 5-HT3 receptor expression in various neural cells of the central and peripheral nervous systems. Although the function and distribution of the 5-HT3 receptor has been well established, its role in the inner ear is still poorly understood. Moreover, no study has yet determined its localization and function in the peripheral vestibular nervous system. In the present study, we reveal mRNA expression of both 5-HT3A and 5-HT3B receptor subunits in the mouse vestibular ganglion (VG) by RT-PCR and in situ hybridization (ISH). We also show by ISH that 5-HT3 receptor mRNA is only expressed in the VG (superior and inferior division) in the peripheral vestibular nervous system. Moreover, we performed Ca(2+) imaging to determine whether functional 5-HT3 receptors are present in the mouse VG, using a selective 5-HT3 receptor agonist, SR57227A. In wild mice, 32% of VG neurons responded to the agonist, whereas there was no response in 5-HT3A receptor knockout mice. These results indicate that VG cells express functional 5-HT3 receptor channels and might play a modulatory role in the peripheral vestibular nervous system. PMID:24530269

Takimoto, Yasumitsu; Ishida, Yusuke; Nakamura, Yukiko; Kamakura, Takefumi; Yamada, Takahiro; Kondo, Makoto; Kitahara, Tadashi; Uno, Atsuhiko; Imai, Takao; Horii, Arata; Okazaki, Suzuyo; Nishiike, Suetaka; Inohara, Hidenori; Shimada, Shoichi

2014-04-01

73

Postural Compensation for Vestibular Loss  

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To what extent can remaining sensory information and/or sensory biofeedback compensate for loss of vestibular information in controlling postural equilibrium? The primary role of the vestibulospinal system is as a vertical reference for control of the trunk in space, with increasing importance as the surface becomes increasingly unstable. Our studies with patients with bilateral loss of vestibular function show that vision or light touch from a fingertip can substitute as a reference for eart...

Horak, Fay B.

2010-01-01

74

Postural Compensation for Vestibular Loss  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To what extent can remaining sensory information and/or sensory biofeedback compensate for loss of vestibular information in controlling postural equilibrium? The primary role of the vestibulospinal system is as a vertical reference for control of the trunk in space, with increasing importance as the surface becomes increasingly unstable. Our studies with patients with bilateral loss of vestibular function show that vision or light touch from a fingertip can substitute as a reference for eart...

Horak, Fay B.

2009-01-01

75

LITERATURA E VESTIBULAR: DISCURSOS CRUZADOS  

Directory of Open Access Journals (Sweden)

Full Text Available Este trabalho tem o propósito de refletir sobre a relação do aluno-leitor com o texto literário, considerando a leitura como prática determinada por coerções aplicadas por uma instância de controle de caráter avaliativo-seletivo: a instituição concurso vestibular. O enfoque deste estudo, portanto, recai sobre a relação literatura e vestibular, observando em que medida o gênero literário cumpre sua função diante do discurso pedagógico, que é marcado por princípios de controle e sujeição.

MARIA FÁTIMA CRUVINEL

2006-01-01

76

Atypical Manifestation of Vestibular Schwannoma  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction ?Vestibular schwannoma (also known as acoustic neuroma) is a benign tumor whose cells are derived from Schwann sheaths, which commonly occurs from the vestibular portion of the eighth cranial nerve. Furthermore, vestibular schwannomas account for ?8% of intracranial tumors in adults an [...] d 80 to 90% of tumors of the cerebellopontine angle. Its symptoms are varied, but what stands out most is a unilateral sensorineural hearing loss, with a low index of speech recognition. Objective ?Describe an atypical manifestation of vestibular schwannoma. Case Report ?The 46-year-old woman had vertigo and binaural hearing loss and fullness, with ear, nose, and throat examination suggestive of cochlear injury. After 6 months, the patient developed worsening of symptoms and onset of right unilateral tinnitus. In further exams the signs of cochlear damage remained, except for the vestibular test (hyporeflexia). Magnetic resonance imaging showed an expansive lesion in the right cerebellopontine angle. Discussion ?This report warns about the atypical manifestations of vestibular schwannoma, which must always be remembered in investigating and diagnosing hearing loss.

Guilherme, Webster; Rui Carlos, Ortega Filho; Antonini de Oliveira e, Sousa; Marcio Cavalcante, Salmito; Mariana Lopes, Favero; Patricia Maria Sens, Marques.

77

Vulnerability of the vestibular organs to transient ischemia: implications for isolated vascular vertigo.  

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The aim of this study was to elucidate the mechanism of isolated vascular vertigo by determining selective and relative ischemic vulnerability of the vestibular structures using a global hypoperfusion model in rats. Sprague-Dawley male rats weighing 330-350 g were subjected to transient global ischemia of the brain using a 4-vessel-occlusion (4VO) model. After permanent occlusion of both vertebral arteries (VA) using electrocauterization, both common carotid arteries (CCAs) were occluded for 5-20 min with ligation. One hour after reperfusion of the CCAs, the animals were sacrificed and subjected to c-Fos staining of the entire cerebellum, brainstem, and vestibular ganglion. The rats in the sham group received the same surgical procedures except the vessel ligation. With 4VO for 5-15 min, both the sham and experimental groups showed a weak and scarce c-Fos expression in the medial vestibular nucleus (MVN), neuron Y, and cochlear nucleus. After 4VO for 20 min, only the MVN began to show a significant difference in the number of c-Fos positive neurons between the experimental and sham groups (33.7±17.7 vs.7.1±5.1, Wilcoxon rank test, p=0.005). With 4VO for up to 20 min, c-Fos positive neurons were not found in other areas of the brainstem and cerebellum, including the superior, lateral, and spinal vestibular nuclei, the vestibular ganglion, the cerebellar cortex, and the deep cerebellar nuclei. The vestibular structures appear to be vulnerable to ischemia more than any other structures in the brainstem and cerebellum. Of the vestibular structures, the MVN is most vulnerable to ischemic insults in rats. These findings are consistent with the common findings of vertigo as an initial and isolated symptom of posterior circulation ischemia in human. PMID:24269984

Lee, Jin Ok; Park, Seong-Ho; Kim, Hyo Jung; Kim, Min Sun; Park, Byung Rim; Kim, Ji-Soo

2014-01-13

78

[Vestibular disorders and methods for their correction].  

Science.gov (United States)

The analysis of etiological agents and clinical presentations of vestibular disorders was presented in the article. Pathogenetic way of treatment of vestibular disorders is substantiated by the author. The paper gives data obtained which show Betaserk treatment efficacy. PMID:14965013

Mironenko, T V

2003-12-01

79

Vestibular control of entorhinal cortex activity in spatial navigation  

Directory of Open Access Journals (Sweden)

Full Text Available Navigation in rodents depends on both self-motion (idiothetic and external (allothetic information. Idiothetic information has a predominant role when allothetic information is absent or irrelevant. The vestibular system is a major source of idiothetic information in mammals. By integrating the signals generated by angular and linear accelerations during exploration, a rat is able to generate and update a vector pointing to its starting place and to perform accurate return. This navigation strategy, called path integration, has been shown to involve a network of brain structures. Among these structures, the entorhinal cortex (EC may play a pivotal role as suggested by lesion and electrophysiological data. In particular, it has been recently discovered that some neurons in the medial EC display multiple firing fields producing a regular grid-like pattern across the environment. Such regular activity may arise from the integration of idiothetic information. This hypothesis would be strongly strengthened if it was shown that manipulation of vestibular information interferes with grid cell activity. In the present paper we review neuroanatomical and functional evidence indicating that the vestibular system influences the activity of the brain network involved in spatial navigation. We also provide new data on the effects of reversible inactivation of the peripheral vestibular system on the EC theta rhythm. The main result is that TTX administration abolishes velocity-controlled theta oscillations in the EC, indicating that vestibular information is necessary for EC activity. Since recent data demonstrate that disruption of theta rhythm in the medial EC induces a disorganization of grid cell firing, our findings indicate that the integration of idiothetic information in the EC is essential to form a spatial representation of the environment.

FrancescaSargolini

2014-06-01

80

RECORDING OF VESTIBULAR EVOKED MYOGENIC POTENTIALS  

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It has been shown recently that loud clicks evoke myogenic potentials in the tonically contracting sternocleidomastoid muscles. Studies have suggested that these potentials are of vestibular origin, especially of the saccule and inferior vestibular nerve. A pilot study was undertaken in our hospital to record vestibular evoked myogenic potentials (VEMP) for the first time in Iran. Eighteen healthy volunteers (32 ears) without history of otologic or vestibular disorders were subjected to the V...

Sazgar, A. A.; Akrami, K.; Karimi Yazdi, S. Akrami A. R.

2006-01-01

 
 
 
 
81

Ocular Vestibular Evoked Myogenic Potentials  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction? Diagnostic testing of the vestibular system is an essential component of treating patients with balance dysfunction. Until recently, testing methods primarily evaluated the integrity of the horizontal semicircular canal, which is only a portion of the vestibular system. Recent advance [...] s in technology have afforded clinicians the ability to assess otolith function through vestibular evoked myogenic potential (VEMP) testing. VEMP testing from the inferior extraocular muscles of the eye has been the subject of interest of recent research. Objective? To summarize recent developments in ocular VEMP testing. Results? Recent studies suggest that the ocular VEMP is produced by otolith afferents in the superior division of the vestibular nerve. The ocular VEMP is a short latency potential, composed of extraocular myogenic responses activated by sound stimulation and registered by surface electromyography via ipsilateral otolithic and contralateral extraocular muscle activation. The inferior oblique muscle is the most superficial of the six extraocular muscles responsible for eye movement. Therefore, measurement of ocular VEMPs can be performed easily by using surface electrodes on the skin below the eyes contralateral to the stimulated side. Conclusion? This new variation of the VEMP procedure may supplement conventional testing in difficult to test populations. It may also be possible to use this technique to evaluate previously inaccessible information on the vestibular system.

Lilian, Felipe; Herman, Kingma.

82

Compensation following bilateral vestibular damage  

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Full Text Available Bilateral loss of vestibular inputs affects far fewer patients than unilateral inner ear damage, and thus has been understudied. In both animal subjects and human patients, bilateral vestibular hypofunction (BVH produces a variety of clinical problems, including impaired balance control, inability to maintain stable blood pressure during postural changes, difficulty in visual targeting of images, and disturbances in spatial memory and navigational performance. Experiments in animals have shown that nonlabyrinthine inputs to the vestibular nuclei are rapidly amplified following the onset of BVH, which may explain the recovery of postural stability and orthostatic tolerance that occurs within 10 days. However, the loss of the vestibulo-ocular reflex and degraded spatial cognition appear to be permanent in animals with BVH. Current concepts of the compensatory mechanisms in humans with BVH are largely inferential, as there is a lack of data from patients early in the disease process. Translation of animal studies of compensation for BVH into therapeutic strategies and subsequent application in the clinic is the most likely route to improve treatment. In addition to physical therapy, two types of prosthetic devices have been proposed to treat individuals with bilateral loss of vestibular inputs: those that provide tactile stimulation to indicate body position in space, and those that deliver electrical stimuli to branches of the vestibular nerve in accordance with head movements. The relative efficacy of these two treatment paradigms, and whether they can be combined to facilitate recovery, is yet to be ascertained.

BillJYates

2011-12-01

83

Ocular Vestibular Evoked Myogenic Potentials  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction? Diagnostic testing of the vestibular system is an essential component of treating patients with balance dysfunction. Until recently, testing methods primarily evaluated the integrity of the horizontal semicircular canal, which is only a portion of the vestibular system. Recent advance [...] s in technology have afforded clinicians the ability to assess otolith function through vestibular evoked myogenic potential (VEMP) testing. VEMP testing from the inferior extraocular muscles of the eye has been the subject of interest of recent research. Objective? To summarize recent developments in ocular VEMP testing. Results? Recent studies suggest that the ocular VEMP is produced by otolith afferents in the superior division of the vestibular nerve. The ocular VEMP is a short latency potential, composed of extraocular myogenic responses activated by sound stimulation and registered by surface electromyography via ipsilateral otolithic and contralateral extraocular muscle activation. The inferior oblique muscle is the most superficial of the six extraocular muscles responsible for eye movement. Therefore, measurement of ocular VEMPs can be performed easily by using surface electrodes on the skin below the eyes contralateral to the stimulated side. Conclusion? This new variation of the VEMP procedure may supplement conventional testing in difficult to test populations. It may also be possible to use this technique to evaluate previously inaccessible information on the vestibular system.

Lilian, Felipe; Herman, Kingma.

2014-01-01

84

Role of the medial medullary reticular formation in relaying vestibular signals to the diaphragm and abdominal muscles  

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Changes in posture can affect the resting length of respiratory muscles, requiring alterations in the activity of these muscles if ventilation is to be unaffected. Recent studies have shown that the vestibular system contributes to altering respiratory muscle activity during movement and changes in posture. Furthermore, anatomical studies have demonstrated that many bulbospinal neurons in the medial medullary reticular formation (MRF) provide inputs to phrenic and abdominal motoneurons; because this region of the reticular formation receives substantial vestibular and other movement-related input, it seems likely that medial medullary reticulospinal neurons could adjust the activity of respiratory motoneurons during postural alterations. The objective of the present study was to determine whether functional lesions of the MRF affect inspiratory and expiratory muscle responses to activation of the vestibular system. Lidocaine or muscimol injections into the MRF produced a large increase in diaphragm and abdominal muscle responses to vestibular stimulation. These vestibulo-respiratory responses were eliminated following subsequent chemical blockade of descending pathways in the lateral medulla. However, inactivation of pathways coursing through the lateral medulla eliminated excitatory, but not inhibitory, components of vestibulo-respiratory responses. The simplest explanation for these data is that MRF neurons that receive input from the vestibular nuclei make inhibitory connections with diaphragm and abdominal motoneurons, whereas a pathway that courses laterally in the caudal medulla provides excitatory vestibular inputs to these motoneurons.

Mori, R. L.; Bergsman, A. E.; Holmes, M. J.; Yates, B. J.

2001-01-01

85

Does the vestibular system contribute to head direction cell activity in the rat?  

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Head direction cells (HDC) located in several regions of the brain, including the anterior dorsal nucleus of the thalamus (ADN), postsubiculum (PoS), and lateral mammillary nuclei (LMN), provide the neural substrate for the determination of head direction. Although activity of HDC is influenced by various sensory signals and internally generated cues, lesion studies and some anatomical and physiological evidence suggest that vestibular inputs are critical for the maintenance of directional sensitivity of these cells. However, vestibular inputs must be transformed considerably in order to signal head direction, and the neuronal circuitry that accomplishes this signal processing has not been fully established. Furthermore, it is unclear why the removal of vestibular inputs abolishes the directional sensitivity of HDC, as visual and other sensory inputs and motor feedback signals strongly affect the firing of these neurons and would be expected to maintain their directional-related activity. Further physiological studies will be required to establish the role of vestibular system in producing HDC responses, and anatomical studies are needed to determine the neural circuitry that mediates vestibular influences on determination of head direction.

Brown, J. E.; Yates, B. J.; Taube, J. S.; Oman, C. M. (Principal Investigator)

2002-01-01

86

Long-term deficits in motion detection thresholds and spike count variability after unilateral vestibular lesion.  

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The vestibular system operates in a push-pull fashion using signals from both labyrinths and an intricate bilateral organization. Unilateral vestibular lesions cause well-characterized motor deficits that are partially compensated over time and whose neural correlates have been traced in the mean response modulation of vestibular nuclei cells. Here we compare both response gains and neural detection thresholds of vestibular nuclei and semicircular canal afferent neurons in intact vs. unilateral-lesioned macaques using three-dimensional rotation and translation stimuli. We found increased stimulus-driven spike count variability and detection thresholds in semicircular canal afferents, although mean responses were unchanged, after contralateral labyrinth lesion. Analysis of trial-by-trial spike count correlations of a limited number of simultaneously recorded pairs of canal afferents suggests increased noise correlations after lesion. In addition, we also found persistent, chronic deficits in rotation detection thresholds of vestibular nuclei neurons, which were larger in the ipsilesional than the contralesional brain stem. These deficits, which persisted several months after lesion, were due to lower rotational response gains, whereas spike count variability was similar in intact and lesioned animals. In contrast to persistent deficits in rotation threshold, translation detection thresholds were not different from those in intact animals. These findings suggest that, after compensation, a single labyrinth is sufficient to recover motion sensitivity and normal thresholds for the otolith, but not the semicircular canal, system. PMID:24848470

Yu, Xiong-Jie; Thomassen, Jakob S; Dickman, J David; Newlands, Shawn D; Angelaki, Dora E

2014-08-15

87

Early vestibular processing does not discriminate active from passive self-motion if there is a discrepancy between predicted and actual proprioceptive feedback.  

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Most of our sensory experiences are gained by active exploration of the world. While the ability to distinguish sensory inputs resulting of our own actions (termed reafference) from those produced externally (termed exafference) is well established, the neural mechanisms underlying this distinction are not fully understood. We have previously proposed that vestibular signals arising from self-generated movements are inhibited by a mechanism that compares the internal prediction of the proprioceptive consequences of self-motion to the actual feedback. Here we directly tested this proposal by recording from single neurons in monkey during vestibular stimulation that was externally produced and/or self-generated. We show for the first time that vestibular reafference is equivalently canceled for self-generated sensory stimulation produced by activation of the neck musculature (head-on-body motion), or axial musculature (combined head and body motion), when there is no discrepancy between the predicted and actual proprioceptive consequences of self-motion. However, if a discrepancy does exist, central vestibular neurons no longer preferentially encode vestibular exafference. Specifically, when simultaneous active and passive motion resulted in activation of the same muscle proprioceptors, neurons robustly encoded the total vestibular input (i.e., responses to vestibular reafference and exafference were equally strong), rather than exafference alone. Taken together, our results show that the cancellation of vestibular reafference in early vestibular processing requires an explicit match between expected and actual proprioceptive feedback. We propose that this vital neuronal computation, necessary for both accurate sensory perception and motor control, has important implications for a variety of sensory systems that suppress self-generated signals. PMID:24671531

Brooks, Jessica X; Cullen, Kathleen E

2014-06-15

88

Hypothalamic histaminergic and orexinergic modulation on cerebellar and vestibular motor control.  

Science.gov (United States)

Somatic-nonsomatic integration is critical for generation and execution of an appropriate and coordinated behavioral response to changes in internal and external environments. However, the underlying neural substrates and mechanisms are still enigmatic. Intriguingly, the central histaminergic and orexinergic systems originating from the hypothalamus, a high autonomic regulatory center, innervate almost the whole brain including various subcortical motor structures, particularly the cerebellum and vestibular nuclei. Here, we suggest that the hypothalamic histaminergic and orexinergic system bridging the nonsomatic center to somatic motor structures may actively modulate the cerebellar and vestibular nuclear neurons and subsequently participate in motor control and somatic-nonsomatic integration. PMID:23299849

Zhang, Xiao-Yang; Yu, Lei; Zhuang, Qian-Xing; Zhang, Jun; Zhu, Jing-Ning; Wang, Jian-Jun

2013-06-01

89

Human visual and vestibular heading perception in the vertical planes.  

Science.gov (United States)

Heading estimation has not previously been reported in the vertical planes. This is a potentially interesting issue because although distribution of neuronal direction sensitivities is near uniform for vertical headings, there is an overrepresentation of otolith organs sensitive to motion in the horizontal relative to the vertical plane. Furthermore, thresholds of horizontal motion perception are considerably lower than those of vertical motion which has the potential to bias heading perception. The current data from 14 human subjects (age 19 to 67) measured heading estimation in response to vestibular motion of 14 cm (28 cm/s) over a 360° of headings at 5° intervals. An analogous visual motion was tested in separate trials. In this study, earth and head vertical/horizontal were always aligned. Results demonstrated that the horizontal component of heading was overestimated relative to the vertical component for vestibular heading stimuli in the coronal (skew) and sagittal (elevation) planes. For visual headings, the bias was much smaller and in the opposite direction such that the vertical component of heading was overestimated. Subjects older than 50 had significantly worse precision and larger biases relative to that of younger subjects for the vestibular conditions, although visual heading estimates were similar. A vector addition model was fit to the data which explains the observed heading biases by the known distribution of otolith organs in humans. The greatly decreased precision with age is explained by the model with decreases in end organ numbers, and relatively greater loss of otoliths that are sensitive to vertical motion. PMID:24249574

Crane, Benjamin T

2014-02-01

90

Developmental changes in the expression of ?v1 potassium channels in rat vestibular ganglion cells.  

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The primary afferent neurons of the vestibular ganglion convey sensory information from hair cells in the semicircular canals and otolith organs to the vestibular nuclei, the adjacent brainstem and the cerebellum. The intrinsic firing properties of vestibular ganglion cells (VGCs) are heterogeneous and have been classified into phasic, intermediate and tonic firing types on the basis of their response to injected depolarizing currents. A previous study from our group showed that the proportion of phasic discharging VGCs decreased during the first postnatal weeks. Moreover, ?-dendrotoxin (?-DTX), a Kv1 potassium channels antagonist, turned neuron phasic firing to tonic, thus suggesting that these channels play an important role in the developmental changes of VGCs firing patterns. Here, by using immunohistochemistry, Western blotting and quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR), we explored the change in the expression of ?-DTX-sensitive K(+) channels, Kv1.1, Kv1.2 and Kv1.6 in rat VGCs during early postnatal periods. We showed that expression of Kv1.6 protein is down-regulated together with expression of Kv1.6 mRNA after postnatal day 7 in rat VGCs whereas expression of Kv1.1 and Kv1.2 proteins did not change during the same developmental period. Our results suggest that down-regulation of the Kv1.6 protein and mRNA may be associated with maturation of excitable properties of primary vestibular neurons. PMID:22079321

Iwasaki, Shinichi; Nakajima, Toshiaki; Chihara, Yasuhiro; Inoue, Aki; Fujimoto, Chisato; Yamasoba, Tatsuya

2012-01-01

91

Vestibular Findings in Military Band Musicians  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction Exposure to music is the subject of many studies because it is related to an individual's professional and social activities. Objectives Evaluate the vestibular behavior in military band musicians. Methods A retrospective cross-sectional study was performed. Nineteen musicians w [...] ith ages ranging from 21 to 46 years were evaluated (average?=?33.7 years and standard deviation?=?7.2 years). They underwent anamnesis and vestibular and otolaryngologic evaluation through vectoelectronystagmography. Results The most evident otoneurologic symptoms in the anamnesis were tinnitus (84.2%), hearing difficulties (47.3%), dizziness (36.8%), headache (26.3%), intolerance to intense sounds (21.0%), and earache (15.7%). Seven musicians (37.0%) showed vestibular abnormality, which occurred in the caloric test. The abnormality was more prevalent in the peripheral vestibular system, and there was a predominance of irritative peripheral vestibular disorders. Conclusion The alteration in vestibular exam occurred in the caloric test (37.0%). There were changes in the prevalence of peripheral vestibular system with a predominance of irritative vestibular dysfunction. Dizziness was the most significant symptom for the vestibular test in correlation with neurotologic symptoms. The present study made it possible to verify the importance of the labyrinthine test, which demonstrates that this population should be better studied because the systematic exposure to high sound pressure levels may cause major vestibular alterations.

Bianca Simone, Zeigelboim; Crislaine, Gueber; Thanara Pruner da, Silva; Paulo Breno Noronha, Liberalesso; Claudia Giglio de Oliveira, Gonçalves; João Henrique, Faryniuk; Jair Mendes, Marques; Ari Leon, Jurkiewicz.

2014-04-01

92

Vestibular Findings in Military Band Musicians  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction Exposure to music is the subject of many studies because it is related to an individual's professional and social activities. Objectives Evaluate the vestibular behavior in military band musicians. Methods A retrospective cross-sectional study was performed. Nineteen musicians w [...] ith ages ranging from 21 to 46 years were evaluated (average?=?33.7 years and standard deviation?=?7.2 years). They underwent anamnesis and vestibular and otolaryngologic evaluation through vectoelectronystagmography. Results The most evident otoneurologic symptoms in the anamnesis were tinnitus (84.2%), hearing difficulties (47.3%), dizziness (36.8%), headache (26.3%), intolerance to intense sounds (21.0%), and earache (15.7%). Seven musicians (37.0%) showed vestibular abnormality, which occurred in the caloric test. The abnormality was more prevalent in the peripheral vestibular system, and there was a predominance of irritative peripheral vestibular disorders. Conclusion The alteration in vestibular exam occurred in the caloric test (37.0%). There were changes in the prevalence of peripheral vestibular system with a predominance of irritative vestibular dysfunction. Dizziness was the most significant symptom for the vestibular test in correlation with neurotologic symptoms. The present study made it possible to verify the importance of the labyrinthine test, which demonstrates that this population should be better studied because the systematic exposure to high sound pressure levels may cause major vestibular alterations.

Bianca Simone, Zeigelboim; Crislaine, Gueber; Thanara Pruner da, Silva; Paulo Breno Noronha, Liberalesso; Claudia Giglio de Oliveira, Gonçalves; João Henrique, Faryniuk; Jair Mendes, Marques; Ari Leon, Jurkiewicz.

93

Effects of visceral inputs on the processing of labyrinthine signals by the inferior and caudal medial vestibular nuclei: ramifications for the production of motion sickness.  

Science.gov (United States)

Neurons located in the caudal aspect of the vestibular nucleus complex have been shown to receive visceral inputs and project to brainstem regions that participate in generating emesis, such as nucleus tractus solitarius and the "vomiting region" in the lateral tegmental field (LTF). Consequently, it has been hypothesized that neurons in the caudal vestibular nuclei participate in triggering motion sickness and that visceral inputs to the vestibular nucleus complex can affect motion sickness susceptibility. To obtain supporting evidence for this hypothesis, we determined the effects of intragastric infusion of copper sulfate (CuSO4) on responses of neurons in the inferior and caudal medial vestibular nuclei to rotations in vertical planes. CuSO4 readily elicits nausea and emesis by activating gastrointestinal (GI) afferents. Infusion of CuSO4 produced a >30 % change in spontaneous firing rate of approximately one-third of neurons in the caudal aspect of the vestibular nucleus complex. These changes in firing rate developed over several minutes, presumably in tandem with the emetic response. The gains of responses to vertical vestibular stimulation of a larger fraction (approximately two-thirds) of caudal vestibular nucleus neurons were altered over 30 % by administration of CuSO4. The response gains of some units went up, and others went down, and there was no significant relationship with concurrent spontaneous firing rate change. These findings support the notion that the effects of visceral inputs on motion sickness susceptibility are mediated in part through the caudal vestibular nuclei. However, our previous studies showed that infusion of CuSO4 produced larger changes in response to vestibular stimulation of LTF neurons, as well as parabrachial nucleus neurons that are believed to participate in generating nausea. Thus, integrative effects of GI inputs on the processing of labyrinthine inputs must occur at brain sites that participate in eliciting motion sickness in addition to the caudal vestibular nuclei. It seems likely that the occurrence of motion sickness requires converging inputs to brain areas that generate nausea and vomiting from a variety of regions that process vestibular signals. PMID:23712685

Arshian, Milad S; Puterbaugh, Sonya R; Miller, Daniel J; Catanzaro, Michael F; Hobson, Candace E; McCall, Andrew A; Yates, Bill J

2013-07-01

94

Changes in TNF?, NF?B and MnSOD protein in the vestibular nuclei after unilateral vestibular deafferentation  

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Full Text Available Abstract Background Unilateral vestibular deafferentation results in strong microglial and astroglial activation in the vestibular nuclei (VN that could be due to an inflammatory response. This study was aimed at determining if markers of inflammation are upregulated in the VN after chemical unilateral labyrinthectomy (UL in the rat, and if the inflammatory response, if any, induces the expression of neuroprotective factors that could promote the plasticity mechanisms involved in the vestibular compensation process. The expressions of inflammatory and neuroprotective factors after chemical or mechanical UL were also compared to verify that the inflammatory response was not due to the toxicity of sodium arsanilate. Methods Immunohistological investigations combined the labeling of tumor necrosis factor ? (TNF?, as a marker of the VN inflammatory response, and of nuclear transcription factor ?B (NF?B and manganese superoxide dismutase (MnSOD, as markers of neuroprotection that could be expressed in the VN because of inflammation. Immunoreactivity (Ir of the VN cells was quantified in the VN complex of rats. Behavioral investigations were performed to assess the functional recovery process, including both static (support surface and dynamic (air-righting and landing reflexes postural tests. Results Chemical UL (arsanilate transtympanic injection induced a significant increase in the number of TNF?-Ir cells in the medial and inferior VN on both sides. These changes were detectable as early as 4 h after vestibular lesion, persisted at 1 day, and regained nearly normal values at 3 days. The early increase in TNF? expression was followed by a slightly delayed upregulation of NF?B 8 h after chemical UL, peaking at 1 day, and regaining control values 3 days later. By contrast, upregulation of MnSOD was more strongly delayed (1 day, with a peak at 3 days, and a return to control values at 15 days. Similar changes of TNF?, NF?B, and MnSOD expression were found in rats submitted to mechanical UL. Behavioral observations showed strong posturo-locomotor deficits early after chemical UL (1 day and a complete functional recovery 6 weeks later. Conclusions Our results suggest that the upregulation of inflammatory and neuroprotective factors after vestibular deafferentation in the VN may constitute a favorable neuronal environment for the vestibular compensation process.

Lacour Michel

2010-12-01

95

Schwannoma vestibular: involução tumoral espontânea Vestibular Schwannoma: spontaneous tumor involution  

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A história natural dos schwannomas vestibulares ainda não está totalmente elucidada, mas sua maioria tende a apresentar crescimento lento, muitos permanecendo sem sintomas durante toda a vida do paciente. Cerca de 69% deste tipo de tumor diagnosticados não apresentam crescimento e, destes, 16% chegam a apresentar regressão tumoral. Considerando os tumores que apresentam crescimento, cerca de 70% crescem menos de 2 mm ao ano. O avanço nos métodos de diagnóstico por imagem, particularme...

Norma de Oliveira Penido; Tangerina, Rodrigo P.; Eduardo Macoto Kosugi; Carlos Eduardo Cesário de Abreu; Matheus Brandão Vasco

2007-01-01

96

Personality Changes in Patients with Vestibular Dysfunction  

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Full Text Available The vestibular system is a sensory system that has evolved to detect linear and angular acceleration of the head in all planes so that the brain is not predominantly reliant on visual information to determine self-motion. Since the vestibular system first evolved in invertebrate species in order to detect gravitational vertical, it is likely that the central nervous system has developed a special dependence upon vestibular input. In addition to the deficits in eye movement and postural reflexes that occur following vestibular dysfunction, there is convincing evidence that vestibular loss also causes cognitive and emotional disorders, some of which may be due to the reflexive deficits and some of which are related to the role that ascending vestibular pathways to the limbic system and cortex play in the sense of spatial orientation. Beyond this, however, patients with vestibular disorders have been reported to experience other personality changes that suggest that vestibular sensation is implicated in the sense of self. These are depersonalisation and derealisation symptoms such as feeling ‘spaced out’, ‘body feeling strange’ and ‘not feeling in control of self’. We suggest in this review that these symptoms suggest that the vestibular system may make a unique contribution to the concept of self through the information regarding self-motion and self-location that it transmits, albeit indirectly, to areas of the brain such as the temporo-parietal junction.

PaulSmith

2013-10-01

97

Swimming behaviour and calcium incorporation into inner ear otoliths of fish after vestibular nerve transection  

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Previous investigations on neonate swordtail fish (Xiphophorus helleri) revealed that otolithic calcium incorporation (visualized using the calcium tracer alizarin complexone) and thus otolith growth had ceased after nerve transection, supporting a hypothesis according to which the gravity-dependent otolith growth is regulated neuronally. Subsequent investigations on larval cichlid fish (Oreochromis mossambicus) yielded contrasting results, repeatedly depending on the particular batch of cichlids investigated. Like most neonate swordtails, Type I cichlids revealed a stop of calcium incorporation after unilateral vestibular nerve transection. Their behaviour after transection was normal, and the otolithic calcium incorporation in controls of the same batch was symmetric. In Type II cichlids, however, vestibular nerve transection had no effect on otolithic calcium incorporation. They behaved kinetotically after transection (this kind of kinetosis was qualitatively similar to the swimming behaviour exhibited by larval cichlids during microgravity in the course of parabolic aircraft flights). The otolithic calcium incorporation in control animals was asymmetric. These results show that the effects of vestibular nerve transection as well as the efficacy of the mechanism, which regulates otolith growth/otolithic calcium incorporation, are - depending on the particular batch of animals - genetically predispositioned. In conclusion, the regulation of otolithic calcium incorporation is guided neuronally, in part via the vestibular nerve and, in part, via a further pathway, which remains to be addressed in the course of future investigations.

Edelmann, E.; Anken, R. H.; Rahmann, H.

2004-01-01

98

BRN 3.1 Knockouts Affect the Vestibular, Autonomic, and Circadian Rhythm Responses to 2G Exposure  

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Our previous studies have demonstrated that 2G exposure via centrifugation significantly attenuated the daily mean and circadian rhythm amplitude of rat body temperature (Tb), heart rate, and activity (Act). In addition, 2G exposure activates neural responses in several vestibular, autonomic, and circadian nuclei. Although we have characterized the effect of 2G on an animal's physiological, neuronal, and behavioral responses, it will be important to understand the underlying neural and physiological mechanisms that mediate those responses. For example, the vestibular responses, proprioceptive feedback, or fluid shifts may be the critical factors that mediate the responses to 2G. As a first step to understand the relative importance of these different response pathways to altered gravitational fields, this study examined the contribution of the vestibular system by utilizing an animal model from molecular biology. Brain 3.1 (Bm 3.1) is a POU domain homeobox gene involved in the normal development of the vestibular and auditory system. Brn 3.1 deletion results in a loss of hair cells in the otoliths, semicircular canals, and cochlea. As a result mice with a Brn 3.1 deletion do not have a functioning vestibular or auditory system. The BRN 3.1 knockout mouse could be a very useful animal model for isolating the role of the vestibular system in mediating the physiological responses to 2G exposure. Therefore, this study compared the effect of 2G exposure via centrifugation between Brn 3.1 knockout (KO) versus Wildtype (W) mice.

Murakami, D. M.; Erkman, L.; Rosenfeld, M. G.; Fuller, C. A.

1999-01-01

99

Effects of microgravity on vestibular development and function in rats: genetics and environment  

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Our anatomical and behavioral studies of embryonic rats that developed in microgravity suggest that the vestibular sensory system, like the visual system, has genetically mediated processes of development that establish crude connections between the periphery and the brain. Environmental stimuli also regulate connection formation including terminal branch formation and fine-tuning of synaptic contacts. Axons of vestibular sensory neurons from gravistatic as well as linear acceleration receptors reach their targets in both microgravity and normal gravity, suggesting that this is a genetically regulated component of development. However, microgravity exposure delays the development of terminal branches and synapses in gravistatic but not linear acceleration-sensitive neurons and also produces behavioral changes. These latter changes reflect environmentally controlled processes of development.

Ronca, A. E.; Fritzsch, B.; Alberts, J. R.; Bruce, L. L.

2000-01-01

100

Special (vestibular training of servicemen  

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Full Text Available It has been shown that conditions of professional activity of airmobile servicemen require from them, in addition to excellent proficiency in military armament and materiel, high level of physical qualities and movement coordination development. It is essential to have high practice of vestibular apparatus, which helps to resist such negative feature as air sickness. The essences of term air sickness, its negative consequences for professional activity are highlighted. Possible tendencies of work in terms of enhancing organism resistance to air sickness (according to the analysis of publications and practical experience are investigated.

Afonin V.M.

2011-02-01

 
 
 
 
101

Causal links between dorsal medial superior temporal area neurons and multisensory heading perception.  

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The dorsal medial superior temporal area (MSTd) in the extrastriate visual cortex is thought to play an important role in heading perception because neurons in this area are tuned to both optic flow and vestibular signals. MSTd neurons also show significant correlations with perceptual judgments during a fine heading direction discrimination task. To test for a causal link with heading perception, we used microstimulation and reversible inactivation techniques to artificially perturb MSTd activity while monitoring behavioral performance. Electrical microstimulation significantly biased monkeys' heading percepts based on optic flow, but did not significantly impact vestibular heading judgments. The latter result may be due to the fact that vestibular heading preferences in MSTd are more weakly clustered than visual preferences and multiunit tuning for vestibular stimuli is weak. Reversible chemical inactivation, however, increased behavioral thresholds when heading judgments were based on either optic flow or vestibular cues, although the magnitude of the effects was substantially stronger for optic flow. Behavioral deficits in a combined visual/vestibular stimulus condition were intermediate between the single-cue effects. Despite deficits in discrimination thresholds, animals were able to combine visual and vestibular cues near optimally, even after large bilateral muscimol injections into MSTd. Simulations show that the overall pattern of results following inactivation is consistent with a mixture of contributions from MSTd and other areas with vestibular-dominant tuning for heading. Our results support a causal link between MSTd neurons and multisensory heading perception but suggest that other multisensory brain areas also contribute. PMID:22396405

Gu, Yong; Deangelis, Gregory C; Angelaki, Dora E

2012-02-15

102

Multimodal integration of self-motion cues in the vestibular system: active versus passive translations.  

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The ability to keep track of where we are going as we navigate through our environment requires knowledge of our ongoing location and orientation. In response to passively applied motion, the otolith organs of the vestibular system encode changes in the velocity and direction of linear self-motion (i.e., heading). When self-motion is voluntarily generated, proprioceptive and motor efference copy information is also available to contribute to the brain's internal representation of current heading direction and speed. However to date, how the brain integrates these extra-vestibular cues with otolith signals during active linear self-motion remains unknown. Here, to address this question, we compared the responses of macaque vestibular neurons during active and passive translations. Single-unit recordings were made from a subgroup of neurons at the first central stage of sensory processing in the vestibular pathways involved in postural control and the computation of self-motion perception. Neurons responded far less robustly to otolith stimulation during self-generated than passive head translations. Yet, the mechanism underlying the marked cancellation of otolith signals did not affect other characteristics of neuronal responses (i.e., baseline firing rate, tuning ratio, orientation of maximal sensitivity vector). Transiently applied perturbations during active motion further established that an otolith cancellation signal was only gated in conditions where proprioceptive sensory feedback matched the motor-based expectation. Together our results have important implications for understanding the brain's ability to ensure accurate postural and motor control, as well as perceptual stability, during active self-motion. PMID:24336720

Carriot, Jerome; Brooks, Jessica X; Cullen, Kathleen E

2013-12-11

103

Neural basis of new clinical vestibular tests: otolithic neural responses to sound and vibration.  

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Extracellular single neuron recording and labelling studies of primary vestibular afferents in Scarpa's ganglion have shown that guinea-pig otolithic afferents with irregular resting discharge are preferentially activated by 500 Hz bone-conducted vibration (BCV) and many also by 500 Hz air-conducted sound (ACS) at low threshold and high sensitivity. Very few afferent neurons from any semicircular canal are activated by these stimuli and then only at high intensity. Tracing the origin of the activated neurons shows that these sensitive otolithic afferents originate mainly from a specialized region, the striola, of both the utricular and saccular maculae. This same 500 Hz BCV elicits vestibular-dependent eye movements in alert guinea-pigs and in healthy humans. These stimuli evoke myogenic potentials, vestibular-evoked myogenic potentials (VEMPs), which are used to test the function of the utricular and saccular maculae in human patients. Although utricular and saccular afferents can both be activated by BCV and ACS, the differential projection of utricular and saccular afferents to different muscle groups allows for differentiation of the function of these two sensory regions. The basic neural data support the conclusion that in human patients in response to brief 500 Hz BCV delivered to Fz (the midline of the forehead at the hairline), the cervical VEMP indicates predominantly saccular function and the ocular VEMP indicates predominantly utricular function. The neural, anatomical and behavioural evidence underpins clinical tests of otolith function in humans using sound and vibration. PMID:24754528

Curthoys, Ian S; Vulovic, Vedran; Burgess, Ann M; Manzari, Leonardo; Sokolic, Ljiljana; Pogson, Jacob; Robins, Mike; Mezey, Laura E; Goonetilleke, Samanthi; Cornell, Elaine D; MacDougall, Hamish G

2014-05-01

104

Transforming the vestibular system one molecule at a time: the molecular and developmental basis of vertebrate auditory evolution.  

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We review the molecular basis of auditory development and evolution. We propose that the auditory periphery (basilar papilla, organ of Corti) evolved by transforming a newly created and redundant vestibular (gravistatic) endorgan into a sensory epithelium that could respond to sound instead of gravity. Evolution altered this new epithelia's mechanoreceptive properties through changes of hair cells, positioned the epithelium in a unique position near perilymphatic space to extract sound moving between the round and the oval window, and transformed its otolith covering into a tympanic membrane. Another important step in the evolution of an auditory system was the evolution of a unique set of "auditory neurons" that apparently evolved from vestibular neurons. Evolution of mammalian auditory (spiral ganglion) neurons coincides with GATA3 being a transcription factor found selectively in the auditory afferents. For the auditory information to be processed, the CNS required a dedicated center for auditory processing, the auditory nuclei. It is not known whether the auditory nucleus is ontogenetically related to the vestibular or electroreceptive nuclei, two sensory systems found in aquatic but not in amniotic vertebrates, or a de-novo formation of the rhombic lip in line with other novel hindbrain structures such as pontine nuclei. Like other novel hindbrain structures, the auditory nuclei express exclusively the bHLH gene Atoh1, and loss of Atoh1 results in loss of most of this nucleus in mice. Only after the basilar papilla, organ of Corti evolved could efferent neurons begin to modulate their activity. These auditory efferents most likely evolved from vestibular efferent neurons already present. The most simplistic interpretation of available data suggest that the ear, sensory neurons, auditory nucleus, and efferent neurons have been transformed by altering the developmental genetic modules necessary for their development into a novel direction conducive for sound extraction, conduction, and processing. PMID:22399402

Duncan, Jeremy S; Fritzsch, Bernd

2012-01-01

105

Distribution of Na,K-ATPase ? subunits in rat vestibular sensory epithelia.  

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The afferent encoding of vestibular stimuli depends on molecular mechanisms that regulate membrane potential, concentration gradients, and ion and neurotransmitter clearance at both afferent and efferent relays. In many cell types, the Na,K-ATPase (NKA) is essential for establishing hyperpolarized membrane potentials and mediating both primary and secondary active transport required for ion and neurotransmitter clearance. In vestibular sensory epithelia, a calyx nerve ending envelopes each type I hair cell, isolating it over most of its surface from support cells and posing special challenges for ion and neurotransmitter clearance. We used immunofluorescence and high-resolution confocal microscopy to examine the cellular and subcellular patterns of NKA? subunit expression within the sensory epithelia of semicircular canals as well as an otolith organ (the utricle). Results were similar for both kinds of vestibular organ. The neuronal NKA?3 subunit was detected in all afferent endings-both the calyx afferent endings on type I hair cells and bouton afferent endings on type II hair cells-but was not detected in efferent terminals. In contrast to previous results in the cochlea, the NKA?1 subunit was detected in hair cells (both type I and type II) but not in supporting cells. The expression of distinct NKA? subunits by vestibular hair cells and their afferent endings may be needed to support and shape the high rates of glutamatergic neurotransmission and spike initiation at the unusual type I-calyx synapse. PMID:25091536

Schuth, Olga; McLean, Will J; Eatock, Ruth Anne; Pyott, Sonja J

2014-10-01

106

Recovery of vestibular ocular reflex function and balance control after a unilateral peripheral vestibular deficit.  

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Full Text Available This review describes the effect of unilateral peripheral vestibular deficit (UPVD on balance control as observed in stance and gait tests. Normally, a UPVD is defined based on vestibular ocular reflex (VOR function. Therefore, we compare recovery observed in balance control over time with similar patterns of recovery or lack thereof in VOR function. Three types of UPVD are considered; acute vestibular neuritis, vestibular loss prior to and after cerebellar pontine angle tumor (CPAT surgery during which a vestibular neurectomy was performed, and vestibular loss following neurectomy to eliminate disabling Ménière’s disease. To measure balance control, body-worn gyroscopes, mounted near the body’s centre of mass, were used for stance and gait tests. Measurement variables were the pitch (anterior-posterior and roll (lateral sway angles and angular velocities of the lower trunk-pelvis. All three groups showed balance deficits during stance tasks on foam, especially with eyes closed when stable control is highly dependent on vestibular inputs. Deficits in balance control during gait were present but were more profound for complex gait tasks such as tandem gait. Differences emerged between the groups concerning the severity of the deficit and its recovery. Generally, the effects of acute neuritis were more severe but recovered rapidly, deficits due to vestibular neurectomy were less severe but longer lasting. These results paralleled deficits in VOR function and raise questions about two modes of neural plasticity occurring in the vestibular system following vestibular loss: one mode being the limited central compensation for the loss, and the second mode being some restoration of peripheral vestibular function. Future work will need to correlate deficits in balance control during stance and gait more exactly with VOR deficits and carefully consider the differences between insufficient central compensation compared to inadequate peripheral restoration of function.

JohnAllum

2012-05-01

107

Vestibular function in severe bilateral vestibulopathy  

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OBJECTIVES—To assess residual vestibular function in patients with severe bilateral vestibulopathy comparing low frequency sinusoidal rotation with the novel technique of random, high acceleration rotation of the whole body.?METHODS—Eye movements were recorded by electro-oculography in darkness during passive, whole body sinusoidal yaw rotations at frequencies between 0.05 and 1.6 Hz in four patients who had absent caloric vestibular responses. These were compared w...

Wiest, G.; Demer, J.; Tian, J.; Crane, B.; Baloh, R.

2001-01-01

108

Vestibular development in marsupials and monotremes.  

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The young of marsupials and monotremes are all born in an immature state, followed by prolonged nurturing by maternal lactation in either a pouch or nest. Nevertheless, the level of locomotor ability required for newborn marsupials and monotremes to reach the safety of the pouch or nest varies considerably: some are transferred to the pouch or nest in an egg (monotremes); others are transferred passively by gravity (e.g. dasyurid marsupials); some have only a horizontal wriggle to make (e.g. peramelid and didelphid marsupials); and others must climb vertically for a long distance to reach the maternal pouch (e.g. diprotodontid marsupials). In the present study, archived sections of the inner ear and hindbrain held in the Bolk, Hill and Hubrecht collections at the Museum für Naturkunde, Berlin, were used to test the relationship between structural maturity of the vestibular apparatus and the locomotor challenges that face the young of these different mammalian groups. A system for staging different levels of structural maturity of the vestibular apparatus was applied to the embryos, pouch young and hatchlings, and correlated with somatic size as indicated by greatest body length. Dasyurids are born at the most immature state, with the vestibular apparatus at little more than the otocyst stage. Peramelids are born with the vestibular apparatus at a more mature state (fully developed semicircular ducts and a ductus reuniens forming between the cochlear duct and saccule, but no semicircular canals). Diprotodontids and monotremes are born with the vestibular apparatus at the most mature state for the non-eutherians (semicircular canals formed, maculae present, but vestibular nuclei in the brainstem not yet differentiated). Monotremes and marsupials reach the later stages of vestibular apparatus development at mean body lengths that lie within the range of those found for laboratory rodents (mouse and rat) reaching the same vestibular stage. PMID:24298911

Ashwell, Ken W S; Shulruf, Boaz

2014-04-01

109

Vestibular facilitation of optic flow parsing.  

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Simultaneous object motion and self-motion give rise to complex patterns of retinal image motion. In order to estimate object motion accurately, the brain must parse this complex retinal motion into self-motion and object motion components. Although this computational problem can be solved, in principle, through purely visual mechanisms, extra-retinal information that arises from the vestibular system during self-motion may also play an important role. Here we investigate whether combining vestibular and visual self-motion information improves the precision of object motion estimates. Subjects were asked to discriminate the direction of object motion in the presence of simultaneous self-motion, depicted either by visual cues alone (i.e. optic flow) or by combined visual/vestibular stimuli. We report a small but significant improvement in object motion discrimination thresholds with the addition of vestibular cues. This improvement was greatest for eccentric heading directions and negligible for forward movement, a finding that could reflect increased relative reliability of vestibular versus visual cues for eccentric heading directions. Overall, these results are consistent with the hypothesis that vestibular inputs can help parse retinal image motion into self-motion and object motion components. PMID:22768345

MacNeilage, Paul R; Zhang, Zhou; DeAngelis, Gregory C; Angelaki, Dora E

2012-01-01

110

RECORDING OF VESTIBULAR EVOKED MYOGENIC POTENTIALS  

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Full Text Available It has been shown recently that loud clicks evoke myogenic potentials in the tonically contracting sternocleidomastoid muscles. Studies have suggested that these potentials are of vestibular origin, especially of the saccule and inferior vestibular nerve. A pilot study was undertaken in our hospital to record vestibular evoked myogenic potentials (VEMP for the first time in Iran. Eighteen healthy volunteers (32 ears without history of otologic or vestibular disorders were subjected to the VEMP test. Twenty-one patients (26 ears with unilateral (6 patients and bilateral (5 patients high frequency sensorineural hearing loss with unknown etiology, acoustic neuroma (1 patient, Meniere’s disease (4 patients and unilateral low frequency sensorineural hearing loss without vestibular complaint (5 patients were also enrolled in this study. VEMP response to clicks was obtained from 84.4% of ears of healthy subjects. These subjects demonstrated short latency waves to click stimuli during tonic neck flexor activation. Mean latencies of first positive (p13 and first negative (n23 potentials in healthy subjects were 12.45 ± 1.9 ms and 20.8 ± 3.5 ms, respectively. Median latencies of these two potentials were 12.1 and 19.3 ms, respectively. We could record VEMP in 5 patients with unilateral and all patients with high and low frequency sensorineural hearing loss without vestibular complaint. In the patient with acoustic neuroma VEMP was absent on the affected side. This technique may offer a new method to evaluate otolith and sacculocollic pathways in human.

A. A. Sazgar

2006-05-01

111

Vestibular Evoked Myogenic Potentials in Migraine Patients  

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Full Text Available Background and Aim: Patients with migraine commonly show vestibular symptoms. However, abnormal neurotological test findings during the inter-attack intervals, even in the absence of vestibular symptoms, are suggestive of subclinical vestibular dysfunction in migraine. This study aimed to compare the vestibular evoked myogenic potentials between migraine patients and normal individuals.Methods: Subjects included 25 patients with migraine and 26 healthy volunteers with an age range of 20-53 years old. The vestibular evoked myogenic potentials were recorded with 500 Hz tone bursts at 95 dB nHL.Results: Mean of absolute amplitude and p13 latency values in the migraine group were significantly less and more than the normal group, respectively (p=0.001 for absolute amplitude in right and left ears; p=0.004 for p13 latency in right ears and p=0.02 in left ears. There was no statistically significant difference between the two groups in mean of the n23 latency and also the amplitude ratio (p>0.05.Conclusion: According to the prolonged latency of vestibular evoked myogenic potentials response, vestibulospinal tract in brainstem is probably involved in migraine patients. However, due to small sample size, for generalizing this result to all patients with migraine, further researches are needed.

Shohre Jalaie

2011-06-01

112

Achados vestibulares em pacientes portadores de fibromialgia  

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Full Text Available Introdução: A fibromialgia (FM é uma síndrome musculoesquelética não inflamatória, de caráter crônico, de etiologia desconhecida, caracterizada por dor difusa, aumento da sensibilidade na palpação e por sintomas como fadiga, insônia, ansiedade, depressão, intolerância ao frio e queixas otológicas. Objetivo: Avaliar o comportamento vestibular em pacientes portadores de fibromialgia. Método: Foi realizado um estudo retrospectivo de corte transversal. Avaliaram-se 25 pacientes na faixa etária entre 26 e 65 anos (média de idade - 52,2 anos e desvio padrão - 10,3 anos, submetidos aos seguintes procedimentos: anamnese, avaliação otorrinolaringológica e vestibular por meio da vectoeletronistagmografia. Resultados: a Os sintomas otoneurológicos mais evidenciados foram: dificuldade ou dor ao movimento do pescoço e dor irradiada para ombro ou braço (92,0% em cada, tontura (84,0% e cefaleia (76,0%. Os sintomas clínicos diversos mais relatados foram: depressão (80,0%, ansiedade (76,0% e insônia (72,0%; b O exame vestibular esteve alterado em 12 pacientes (48,0% sendo localizado na prova calórica; c Houve prevalência de alteração no sistema vestibular periférico e, d Houve predomínio das disfunções vestibulares periféricas deficitárias. Conclusão: Este estudo permitiu verificar a importância do exame labiríntico o que ressalta que esse tipo de população deveria ser melhor estudada, uma vez que diversas doenças reumatológicas pelas suas manifestações e áreas de comprometimento podem gerar alterações vestibulares importantes.

Zeigelboim, Bianca Simone

2011-07-01

113

Schwannoma vestibular: involução tumoral espontânea / Vestibular Schwannoma: spontaneous tumor involution  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A história natural dos schwannomas vestibulares ainda não está totalmente elucidada, mas sua maioria tende a apresentar crescimento lento, muitos permanecendo sem sintomas durante toda a vida do paciente. Cerca de 69% deste tipo de tumor diagnosticados não apresentam crescimento e, destes, 16% chega [...] m a apresentar regressão tumoral. Considerando os tumores que apresentam crescimento, cerca de 70% crescem menos de 2 mm ao ano. O avanço nos métodos de diagnóstico por imagem, particularmente à ressonância magnética com contraste de gadolínio, permite o diagnóstico cada vez mais de lesões com sintomas mínimos e tamanhos menores. O tratamento de escolha para estes tumores ainda é a ressecção completa do tumor. As técnicas cirúrgicas apresentaram grande avanço nas últimas décadas, o que possibilitou diminuição da mortalidade. Assim, a cirurgia, que antes tinha como objetivo apenas a ressecção completa do tumor, agora visa também à preservação da audição e da função do nervo facial. Considerações finais: Considerando-se sua história natural, abre-se a possibilidade de uma conduta conservadora já que o ritmo de crescimento no primeiro ano após o diagnóstico prediz o comportamento do tumor nos próximos anos. A conduta conservadora não implica em repúdio à cirurgia, devendo ser utilizada em casos de aumento tumoral, piora dos sintomas ou desejo do paciente. Além disso, em relatos de literatura não há diferença estatisticamente significante entre os pacientes submetidos à cirurgia logo após o diagnóstico ou após conduta conservadora inicial, no que diz respeito às seqüelas pós-operatórias. Abstract in english The natural history of Vestibular Schwannomas (VS) is yet not totally known, but most of them have the tendency to slow growth, sometimes without any kind of symptoms during the individual’s entire time. About 69% of diagnosed VS do not grow at all and 16% of these can even regress. Considering tumo [...] rs that grow, about 70% have grown less than 2mm an year. Advanced radiological diagnosis, especially magnetic resonance imaging with gadolinium helps us diagnose small and less symptomatic tumors. Treatment of choice still is complete tumor resection. Surgical approaches have improved considerably and have helped preserve facial nerve function and hearing. Considering VS’s natural history, there is a possibility for conservative treatment for these tumors, because their growth in the first year after diagnosis predicts tumor growth behavior in the next years. Surgery should be done in cases of tumor growth, patient’s desire or symptoms worsening. Moreover, in terms of postoperative sequelae, there is no difference between patients who underwent surgery immediately after diagnosis and those who underwent initial conservative treatment for these tumors.

Norma de Oliveira, Penido; Rodrigo P., Tangerina; Eduardo Macoto, Kosugi; Carlos Eduardo Cesário de, Abreu; Matheus Brandão, Vasco.

2007-12-01

114

Schwannoma vestibular: involução tumoral espontânea / Vestibular Schwannoma: spontaneous tumor involution  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A história natural dos schwannomas vestibulares ainda não está totalmente elucidada, mas sua maioria tende a apresentar crescimento lento, muitos permanecendo sem sintomas durante toda a vida do paciente. Cerca de 69% deste tipo de tumor diagnosticados não apresentam crescimento e, destes, 16% chega [...] m a apresentar regressão tumoral. Considerando os tumores que apresentam crescimento, cerca de 70% crescem menos de 2 mm ao ano. O avanço nos métodos de diagnóstico por imagem, particularmente à ressonância magnética com contraste de gadolínio, permite o diagnóstico cada vez mais de lesões com sintomas mínimos e tamanhos menores. O tratamento de escolha para estes tumores ainda é a ressecção completa do tumor. As técnicas cirúrgicas apresentaram grande avanço nas últimas décadas, o que possibilitou diminuição da mortalidade. Assim, a cirurgia, que antes tinha como objetivo apenas a ressecção completa do tumor, agora visa também à preservação da audição e da função do nervo facial. Considerações finais: Considerando-se sua história natural, abre-se a possibilidade de uma conduta conservadora já que o ritmo de crescimento no primeiro ano após o diagnóstico prediz o comportamento do tumor nos próximos anos. A conduta conservadora não implica em repúdio à cirurgia, devendo ser utilizada em casos de aumento tumoral, piora dos sintomas ou desejo do paciente. Além disso, em relatos de literatura não há diferença estatisticamente significante entre os pacientes submetidos à cirurgia logo após o diagnóstico ou após conduta conservadora inicial, no que diz respeito às seqüelas pós-operatórias. Abstract in english The natural history of Vestibular Schwannomas (VS) is yet not totally known, but most of them have the tendency to slow growth, sometimes without any kind of symptoms during the individual’s entire time. About 69% of diagnosed VS do not grow at all and 16% of these can even regress. Considering tumo [...] rs that grow, about 70% have grown less than 2mm an year. Advanced radiological diagnosis, especially magnetic resonance imaging with gadolinium helps us diagnose small and less symptomatic tumors. Treatment of choice still is complete tumor resection. Surgical approaches have improved considerably and have helped preserve facial nerve function and hearing. Considering VS’s natural history, there is a possibility for conservative treatment for these tumors, because their growth in the first year after diagnosis predicts tumor growth behavior in the next years. Surgery should be done in cases of tumor growth, patient’s desire or symptoms worsening. Moreover, in terms of postoperative sequelae, there is no difference between patients who underwent surgery immediately after diagnosis and those who underwent initial conservative treatment for these tumors.

Norma de Oliveira, Penido; Rodrigo P., Tangerina; Eduardo Macoto, Kosugi; Carlos Eduardo Cesário de, Abreu; Matheus Brandão, Vasco.

115

Schwannoma vestibular: involução tumoral espontânea Vestibular Schwannoma: spontaneous tumor involution  

Directory of Open Access Journals (Sweden)

Full Text Available A história natural dos schwannomas vestibulares ainda não está totalmente elucidada, mas sua maioria tende a apresentar crescimento lento, muitos permanecendo sem sintomas durante toda a vida do paciente. Cerca de 69% deste tipo de tumor diagnosticados não apresentam crescimento e, destes, 16% chegam a apresentar regressão tumoral. Considerando os tumores que apresentam crescimento, cerca de 70% crescem menos de 2 mm ao ano. O avanço nos métodos de diagnóstico por imagem, particularmente à ressonância magnética com contraste de gadolínio, permite o diagnóstico cada vez mais de lesões com sintomas mínimos e tamanhos menores. O tratamento de escolha para estes tumores ainda é a ressecção completa do tumor. As técnicas cirúrgicas apresentaram grande avanço nas últimas décadas, o que possibilitou diminuição da mortalidade. Assim, a cirurgia, que antes tinha como objetivo apenas a ressecção completa do tumor, agora visa também à preservação da audição e da função do nervo facial. Considerações finais: Considerando-se sua história natural, abre-se a possibilidade de uma conduta conservadora já que o ritmo de crescimento no primeiro ano após o diagnóstico prediz o comportamento do tumor nos próximos anos. A conduta conservadora não implica em repúdio à cirurgia, devendo ser utilizada em casos de aumento tumoral, piora dos sintomas ou desejo do paciente. Além disso, em relatos de literatura não há diferença estatisticamente significante entre os pacientes submetidos à cirurgia logo após o diagnóstico ou após conduta conservadora inicial, no que diz respeito às seqüelas pós-operatórias.The natural history of Vestibular Schwannomas (VS is yet not totally known, but most of them have the tendency to slow growth, sometimes without any kind of symptoms during the individual’s entire time. About 69% of diagnosed VS do not grow at all and 16% of these can even regress. Considering tumors that grow, about 70% have grown less than 2mm an year. Advanced radiological diagnosis, especially magnetic resonance imaging with gadolinium helps us diagnose small and less symptomatic tumors. Treatment of choice still is complete tumor resection. Surgical approaches have improved considerably and have helped preserve facial nerve function and hearing. Considering VS’s natural history, there is a possibility for conservative treatment for these tumors, because their growth in the first year after diagnosis predicts tumor growth behavior in the next years. Surgery should be done in cases of tumor growth, patient’s desire or symptoms worsening. Moreover, in terms of postoperative sequelae, there is no difference between patients who underwent surgery immediately after diagnosis and those who underwent initial conservative treatment for these tumors.

Norma de Oliveira Penido

2007-12-01

116

Reabilitação vestibular em idosos com tontura Vestibular rehabilitation in elderly patients with dizziness  

Directory of Open Access Journals (Sweden)

Full Text Available TEMA: o envelhecimento populacional é um processo natural, manifesta-se por um declínio das funções de diversos órgãos. A reabilitação vestibular (RV é um processo terapêutico que visa promover a redução significativa dos sintomas labirínticos. OBJETIVO: verificar os benefícios dos exercícios de RV por meio da avaliação pré e pós-aplicação do questionário Dizziness Handicap Inventory (DHI - adaptação brasileira. MÉTODO: participaram deste estudo oito idosos com queixa de tontura, na faixa etária de 63 a 82 anos, três do sexo masculino e cinco do sexo feminino. Realizaram-se os seguintes procedimentos: anamnese, inspeção otológica, avaliação vestibular por meio da vectoeletronistagmografia (VENG, aplicação do questionário DHI e dos exercícios de RV de Cawthorne (1944 e Cooksey (1946. RESULTADOS: com relação as queixas auditivas e vestibulares, observou-se a incidência do zumbido, da hipoacusia, da vertigem postural e do desequilíbrio; na avaliação da função vestibular, constataram-se alterações em todos os idosos; as alterações foram na sua maioria na prova calórica com predomínio da hiporreflexia uni e bilateral; constataram-se, no exame vestibular, três casos de síndrome vestibular periférica deficitária unilateral, três casos de síndrome vestibular periférica deficitária bilateral, um caso de síndrome vestibular central deficitária bilateral e um caso de síndrome vestibular central irritativa bilateral; houve melhora significativa dos aspectos físico (p = 0,00413, funcional (p = 0,00006 e emocional (p = 0,03268 após a realização dos exercícios de RV. CONCLUSÃO: o protocolo utilizado de RV promoveu melhora na qualidade de vida dos idosos e auxiliou no processo de compensação vestibular.BACKGROND: the aging of the population is a natural process and is manifested by a decline in the functions of several organs. Vestibular rehabilitation (VR is a therapeutic process that seeks to promote a significant reduction in the symptoms of the labyrinth. AIM: to verify the benefits of VR exercises through the application of the Dizziness Handicap Inventory (DHI questionnaire - Brazilian version - pre and post rehabilitation. METHOD: participants of this study were eight elderly patients with dizziness, ages between 63 and 82 years, three male and five female. The following procedures were carried out: medical history, otologic inspection, vestibular evaluation with vectoelectronystagmography (VENG, application of the DHI questionnaire and of the Cawthorne (1944 and Cooksey (1946 VR exercises. RESULTS: regarding the auditory and vestibular complaints which were referred to in the medical history, the following was observed: presence of tinnitus, hearing loss, postural vertigo and of unbalance. In the evaluation of the vestibular function alterations were observed for all of the participants, mainly in the caloric test, with a prevalence of unilateral and bilateral hypofunction. In the vestibular exam the following was observed: three cases of unilateral peripheral vestibular deficit syndrome, three cases of bilateral peripheral vestibular deficit syndrome, one case of bilateral central vestibular deficit syndrome and one case of irritating bilateral central vestibular syndrome. There was a statistically significant improvement of the following aspects after VR: physical (p=0.00413, functional (p=0.00006 and emotional (p=0.03268. CONCLUSION: the VR protocol favored the improvement of life quality of the participants and was of assistance in the process of vestibular compensation.

Francisco Halilla Zanardini

2007-06-01

117

Reabilitação vestibular em idosos com tontura / Vestibular rehabilitation in elderly patients with dizziness  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese TEMA: o envelhecimento populacional é um processo natural, manifesta-se por um declínio das funções de diversos órgãos. A reabilitação vestibular (RV) é um processo terapêutico que visa promover a redução significativa dos sintomas labirínticos. OBJETIVO: verificar os benefícios dos exercícios de RV [...] por meio da avaliação pré e pós-aplicação do questionário Dizziness Handicap Inventory (DHI) - adaptação brasileira. MÉTODO: participaram deste estudo oito idosos com queixa de tontura, na faixa etária de 63 a 82 anos, três do sexo masculino e cinco do sexo feminino. Realizaram-se os seguintes procedimentos: anamnese, inspeção otológica, avaliação vestibular por meio da vectoeletronistagmografia (VENG), aplicação do questionário DHI e dos exercícios de RV de Cawthorne (1944) e Cooksey (1946). RESULTADOS: com relação as queixas auditivas e vestibulares, observou-se a incidência do zumbido, da hipoacusia, da vertigem postural e do desequilíbrio; na avaliação da função vestibular, constataram-se alterações em todos os idosos; as alterações foram na sua maioria na prova calórica com predomínio da hiporreflexia uni e bilateral; constataram-se, no exame vestibular, três casos de síndrome vestibular periférica deficitária unilateral, três casos de síndrome vestibular periférica deficitária bilateral, um caso de síndrome vestibular central deficitária bilateral e um caso de síndrome vestibular central irritativa bilateral; houve melhora significativa dos aspectos físico (p = 0,00413), funcional (p = 0,00006) e emocional (p = 0,03268) após a realização dos exercícios de RV. CONCLUSÃO: o protocolo utilizado de RV promoveu melhora na qualidade de vida dos idosos e auxiliou no processo de compensação vestibular. Abstract in english BACKGROND: the aging of the population is a natural process and is manifested by a decline in the functions of several organs. Vestibular rehabilitation (VR) is a therapeutic process that seeks to promote a significant reduction in the symptoms of the labyrinth. AIM: to verify the benefits of VR exe [...] rcises through the application of the Dizziness Handicap Inventory (DHI) questionnaire - Brazilian version - pre and post rehabilitation. METHOD: participants of this study were eight elderly patients with dizziness, ages between 63 and 82 years, three male and five female. The following procedures were carried out: medical history, otologic inspection, vestibular evaluation with vectoelectronystagmography (VENG), application of the DHI questionnaire and of the Cawthorne (1944) and Cooksey (1946) VR exercises. RESULTS: regarding the auditory and vestibular complaints which were referred to in the medical history, the following was observed: presence of tinnitus, hearing loss, postural vertigo and of unbalance. In the evaluation of the vestibular function alterations were observed for all of the participants, mainly in the caloric test, with a prevalence of unilateral and bilateral hypofunction. In the vestibular exam the following was observed: three cases of unilateral peripheral vestibular deficit syndrome, three cases of bilateral peripheral vestibular deficit syndrome, one case of bilateral central vestibular deficit syndrome and one case of irritating bilateral central vestibular syndrome. There was a statistically significant improvement of the following aspects after VR: physical (p=0.00413), functional (p=0.00006) and emotional (p=0.03268). CONCLUSION: the VR protocol favored the improvement of life quality of the participants and was of assistance in the process of vestibular compensation.

Francisco Halilla, Zanardini; Bianca Simone, Zeigelboim; Ari Leon, Jurkiewicz; Jair Mendes, Marques; Jackeline, Martins-Bassetto.

118

Pharmacotherapy of vestibular disorders and nystagmus.  

Science.gov (United States)

Vertigo and dizziness are with a life-time prevalence of ~30% among the most common symptoms and are often associated with nystagmus or other oculomotor disorders. The prerequisite for a successful treatment is a precise diagnosis of the underlying disorder. In this overview, the current pharmacological treatment options for peripheral and central vestibular, cerebellar, and oculomotor disorders including nystagmus are described. There are basically seven groups of drugs that can be used (the "7 As"): antiemetics; anti-inflammatory, anti-Menière's, and antimigraine medications; antidepressants, anticonvulsants, and aminopyridines. In acute vestibular neuritis, recovery of the peripheral vestibular function can be improved by treatment with oral corticosteroids. In Menière's disease, a long-term high-dose treatment with betahistine-dihydrochloride (at least 48 mg three times daily) had a significant effect on the frequency of the attacks; the underlying mode of action is evidently an increase in inner-ear blood flow. The use of aminopyridines is a well-established therapeutic principle in the treatment of downbeat and upbeat nystagmus as well as episodic ataxia type 2 and cerebellar gait disorders. As was shown in animal experiments, these potassium channel blockers increase the activity and excitability and normalize irregular firing of cerebellar Purkinje cells. They evidently augment the inhibitory influence of these cells on vestibular and deep cerebellar nuclei. A few studies showed that baclofen improves periodic alternating nystagmus; gabapentin and memantine improve pendular and infantile nystagmus. However, many other eye-movement disorders such as ocular flutter, opsoclonus, central positioning, and see-saw nystagmus are still difficult to treat. Although substantial progress has been made, further state-of-the-art trials must still be performed on many vestibular and oculomotor disorders, namely Menière's disease, vestibular paroxysmia, vestibular migraine, and many forms of central eye-movement disorders. PMID:24057832

Strupp, Michael; Kremmyda, Olympia; Brandt, Thomas

2013-07-01

119

Vestibular-related frontal cortical areas and their roles in smooth-pursuit eye movements: representation of neck velocity, neck-vestibular interactions and memory-based smooth-pursuit  

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Full Text Available Smooth-pursuit eye movements are voluntary responses to small slow-moving objects in the fronto-parallel plane. They evolved in primates, who possess high-acuity foveae, to ensure clear vision about the moving target. The primate frontal cortex contains two smooth-pursuit related areas; the caudal part of the frontal eye fields (FEF and the supplementary eye fields (SEF. Both areas receive vestibular inputs. We review functional differences between the two areas in smooth-pursuit. Most FEF pursuit neurons signal pursuit parameters such as eye velocity and gaze-velocity, and are involved in cancelling the vestibulo-ocular reflex by linear addition of vestibular and smooth-pursuit responses. In contrast, gaze-velocity signals are rarely represented in the SEF. Most FEF pursuit neurons receive neck velocity inputs, while discharge modulation during pursuit and trunk-on-head rotation adds linearly. Linear addition also occurs between neck velocity responses and vestibular responses during head-on-trunk rotation in a task-dependent manner. During cross-axis pursuit-vestibular interactions, vestibular signals effectively initiate predictive pursuit eye movements. Most FEF pursuit neurons discharge during the interaction training after the onset of pursuit eye velocity, making their involvement unlikely in the initial stages of generating predictive pursuit. Comparison of representative signals in the two areas and the results of chemical inactivation during a memory-based smooth-pursuit task indicate they have different roles; the SEF plans smooth-pursuit including working memory of motion-direction, whereas the caudal FEF generates motor commands for pursuit eye movements. Patients with idiopathic Parkinson’s disease were asked to perform this task, since impaired smooth-pursuit and visual working memory deficit during cognitive tasks have been reported in most patients. Preliminary results suggested specific roles of the basal ganglia in memory-based smooth-pursuit.

KikuroFukushima

2011-12-01

120

Interactive Healthcare Systems in the Home: Vestibular Rehabilitation  

DEFF Research Database (Denmark)

Vestibular dysfunction is a balance disorder, causing dizziness that provokes discomfort and fall situations. This paper discusses early results from a project that aims to develop assistive technologies to support home-based rehabilitation for elderly affected by Vestibular dysfunction.

Aarhus, Rikke; Grönvall, Erik

2010-01-01

 
 
 
 
121

Arreflexia pós-calórica bilateral: aplicabilidade clínica da reabilitação vestibular Bilateral vestibular loss after caloric irrigation: clinical aplication of vestibular rehabilitation  

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Full Text Available A perda bilateral da função vestibular é rara em pacientes com vertigem e desequilíbrio, porém os sintomas muitas vezes são incapacitantes e seu tratamento é tema controverso na literatura. OBJETIVO: Nosso objetivo foi avaliar e descrever a resposta clínica de pacientes com distúrbio do equilíbrio corporal secundário à arreflexia vestibular pós-calórica bilateral, documentada pela eletronistagmografia, submetidos à Reabilitação Vestibular. FORMA DE ESTUDO: Retrospectivo, inclui um desenho de descrição de casos. MÉTODO: Foram avaliadas as respostas de 8 pacientes portadores de arreflexia pós-calórica bilateral submetidos à Reabilitação Vestibular, observando-se a relação entre os resultados de exame e sintomas pré e pós-tratamento. A avaliação da resposta clínica foi feita por meio de escala analógico-visual. RESULTADOS: Após a Reabilitação Vestibular, 7 (87,5% dos 8 pacientes submetidos à terapia apresentaram melhora clínica. CONCLUSÃO: embora não seja esperada melhora completa do equilíbrio corporal, a Reabilitação Vestibular é uma terapia eficaz na recuperação desses pacientes.Bilateral vestibular loss is a rare diagnosis among patients with dizziness and imbalance. Nevertheless, symptoms are often disabling and therapy is yet to be establish. AIM: To evaluate and describe the clinical outcome of patients with imbalance due to bilateral vestibular loss after caloric test, treated with An analog visual scale was used to evaluated clinical results. Vestibular Rehabilitation. STUDY DESIGN: Retrospective case report. METHOD: Pre and post treatment outcomes were evaluated in 8 individuals suffering from post caloric bilateral vestibular paresis whose were submitted to vestibular rehabilitation. RESULTS: After Vestibular Rehabilitation, 7 (87,5% of 8 patients had clinical improvement. CONCLUSION: Although is not expected entirely compensation for bilateral vestibular loss, the vestibular rehabilitation may be use as a therapeutic method for these patients.

Roseli Saraiva Moreira Bittar

2004-04-01

122

A função vestibular em indivíduos usuários de implante coclear / Vestibular function in cochlear implant users  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A ocorrência de alteração no equilíbrio no período pós-cirúrgico ao implante coclear varia de 31 a 75%. OBJETIVO: Analisar a função vestibular no período pré e pós-operatório da cirurgia de implante coclear. MATERIAL E MÉTODO: Avaliou-se a função vestibular, por meio da vectoeletronistagmografia, de [...] 38 pacientes, no pré e pós-cirúrgico de implante coclear. RESULTADOS: A principal queixa de desequilíbrio apresentada pelos pacientes foi a tontura, seguida pela vertigem postural e pela vertigem não-postural. Dos 38 pacientes avaliados, 13% deixaram de apresentar desequilíbrio após a cirurgia de implante coclear e apenas 5% referiram piora. Houve uma melhora na sintomatologia vestibular em 13% dos pacientes, sendo que esta possibilidade pode estar relacionada ao fenômeno de compensação vestibular e pela estimulação elétrica. Entretanto, foi observada na prova calórica uma piora na funcionalidade do sistema vestibular, tanto na orelha implantada como na orelha não-implantada. Assim, não há tendência de maior comprometimento na orelha implantada. CONCLUSÃO: O estudo demonstrou que o implante coclear pode comprometer o sistema vestibular em ambas as orelhas. Entretanto, a sintomatologia vestibular ocorre em menor proporção, podendo haver melhora no desequilíbrio após a cirurgia do implante coclear. Abstract in english Balance alterations in the postoperative of cochlear implant surgeries varies from 31 to 75%. AIM: to analyze vestibular function in the pre and postoperative periods of cochlear implanted individuals. MATERIALS AND METHODS: the vestibular function was assessed, through electronystagmography, in 38 [...] patients, in the pre and postoperative of cochlear implant procedures. RESULTS: The main complaint of unbalance reported by patients was dizziness, followed by postural vertigo and non-postural vertigo. Results: 13% of the patients did not show any balance disorder following cochlear implant surgery and just 5% showed symptoms worsening. 13 % of the patients showed an improvement, and this could be related to the vestibular compensation phenomenon and to electric stimulation. However, it was observed, in the caloric responses, a worsening in the vestibular system function, for both implanted and non-implanted ears. Thus, there is no evidence of more damage to the implanted ear. CONCLUSION: the study showed that cochlear implant surgeries could injure the vestibular system in both ears. However, the vestibular symptoms take place in a smaller proportion, and can improve after cochlear implant surgery.

Ariane Solci, Bonucci; Orozimbo Alves, Costa Filho; Luciane Domingues Figueiredo, Mariotto; Regina Célia Bortoleto, Amantini; Kátia de Freitas, Alvarenga.

2008-04-01

123

A função vestibular em indivíduos usuários de implante coclear Vestibular function in cochlear implant users  

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Full Text Available A ocorrência de alteração no equilíbrio no período pós-cirúrgico ao implante coclear varia de 31 a 75%. OBJETIVO: Analisar a função vestibular no período pré e pós-operatório da cirurgia de implante coclear. MATERIAL E MÉTODO: Avaliou-se a função vestibular, por meio da vectoeletronistagmografia, de 38 pacientes, no pré e pós-cirúrgico de implante coclear. RESULTADOS: A principal queixa de desequilíbrio apresentada pelos pacientes foi a tontura, seguida pela vertigem postural e pela vertigem não-postural. Dos 38 pacientes avaliados, 13% deixaram de apresentar desequilíbrio após a cirurgia de implante coclear e apenas 5% referiram piora. Houve uma melhora na sintomatologia vestibular em 13% dos pacientes, sendo que esta possibilidade pode estar relacionada ao fenômeno de compensação vestibular e pela estimulação elétrica. Entretanto, foi observada na prova calórica uma piora na funcionalidade do sistema vestibular, tanto na orelha implantada como na orelha não-implantada. Assim, não há tendência de maior comprometimento na orelha implantada. CONCLUSÃO: O estudo demonstrou que o implante coclear pode comprometer o sistema vestibular em ambas as orelhas. Entretanto, a sintomatologia vestibular ocorre em menor proporção, podendo haver melhora no desequilíbrio após a cirurgia do implante coclear.Balance alterations in the postoperative of cochlear implant surgeries varies from 31 to 75%. AIM: to analyze vestibular function in the pre and postoperative periods of cochlear implanted individuals. MATERIALS AND METHODS: the vestibular function was assessed, through electronystagmography, in 38 patients, in the pre and postoperative of cochlear implant procedures. RESULTS: The main complaint of unbalance reported by patients was dizziness, followed by postural vertigo and non-postural vertigo. Results: 13% of the patients did not show any balance disorder following cochlear implant surgery and just 5% showed symptoms worsening. 13 % of the patients showed an improvement, and this could be related to the vestibular compensation phenomenon and to electric stimulation. However, it was observed, in the caloric responses, a worsening in the vestibular system function, for both implanted and non-implanted ears. Thus, there is no evidence of more damage to the implanted ear. CONCLUSION: the study showed that cochlear implant surgeries could injure the vestibular system in both ears. However, the vestibular symptoms take place in a smaller proportion, and can improve after cochlear implant surgery.

Ariane Solci Bonucci

2008-04-01

124

BETAHISTINE DIHYDROCHLORIDE IN CANINE PERIPHERAL VESTIBULAR SYNDROME DICLORIDRATO DE BETAISTINA NA SÍNDROME VESTIBULAR PERIFÉRICA CANINA  

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Full Text Available Vestibular disease is a common syndrome in small animals that  may resulst of central or peripheral disease. The pathophysiology of peripheral vestibular syndrome is unknown, however it can be related to an abnormal dynamic of endolymphatic fluid or neuritis of the vestibular portion of the VIII cranial nerve.  The recovery of neurological sings is slow and, in chronic cases, the neurological deficits can be irreversible. In veterinary medicine, thera are few medical options to treat this condition, however, in Medicine, betahistine dihydrochloride is used to treat peripheral vestibular disorders. These drug  was used in four dogs with vestibular syndrome. The results showed clinical improvement in 7 to 10 days of treatment and completed recovery in 20 to 30 days, followed by the cure. One year after the treatment, the dogs did not have recurrence of the syndrome. This report shows the use of betahistine dihydrochloride in dogs with peripheral vestibular syndrome, with rapid clinical recover, without laboratorial abnormalities or recurrence of the clinical signs .The results encourage the use of betahistine dihydrochloride in the treatment of  peripheral vestibular disorders in small animals.

KEY WORDS: Betahistine, dog, vestibular syndrome.
A síndrome vestibular periférica é uma condição clínica comum em cães. Várias doenças podem causar essa síndrome. Entretanto, sua patofisiologia ainda é pouco conhecida. As alterações clínicas geralmente são autolimitantes, a recuperação pode ser longa e, em casos crônicos, os déficits neurológicos podem ser irreversíveis. Em medicina veterinária, há poucas opções terapêuticas. Na Medicina, o dicloridrato de betaístina é amplamente utilizado. Essa medicação foi empregada em seis cães com síndrome vestibular periférica. Os resultados mostraram melhora clínica com sete a dez dias de tratamento e recuperação quase completa entre vinte e trinta dias. Este trabalho descreve a utilização da betaistina em cães com síndrome vestibular periférica, a rápida melhora clínica e ausência de efeitos adversos. Os resultados obtidos parecem justificar o uso de dicloridrato de betaistina na terapia de distúrbios vestibulares periféricos em animais de companhia.

PALAVRAS-CHAVES: Betaistina, cão, síndrome vestibular.

Tatiana Champion

2010-04-01

125

Temporal change in NMDA receptor signaling and GABAA receptor expression in rat caudal vestibular nucleus during motion sickness habituation.  

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Repeated exposure to a provocative motion stimulus leads to motion sickness habituation indicative of the existence of central processes to counteract the disturbing properties of the imposed motion. In the present study, we attempt to investigate whether NMDA and GABA(A) receptors in rat caudal vestibular nucleus neurons are involved in motion sickness habituation induced by repeated Ferris-wheel like rotation in daily session (2h/d). We showed that defecation response increased and spontaneous locomotion decreased within 4 sessions (sickness phase). They recovered back to the control level after 7 sessions (habituation phase). Western blot analysis found that NMDA receptor signal molecules: calmodulin protein kinase II and cAMP response element-binding protein (CREB) were both activated during sickness phase, while a prolonged CREB activation was also observed during habituation phase. Real-time quantitative PCR revealed an increase in c-fos and a decrease in Arc mRNA level during sickness phase. We also found an increase in GABA(A) receptor ?1 subunit (GABA(A) ?1) protein level in this stage. These results suggested that altered NMDA receptor signaling and GABA(A) receptor expression level in caudal vestibular nucleus were associated with motion sickness habituation. Furthermore, immunofluorescence and confocal laser scanning microscopy showed that the number of GABA(A) ?1 immunolabeled neurons in caudal vestibular nucleus increased while the number of GABA(A) ?1/Arc double labeled neurons and the average amount of Arc particle in soma of these neurons decreased during sickness phase. It suggested that GABA(A) receptor level might be negatively regulated by Arc protein in caudal vestibular nucleus neurons. PMID:22608069

Wang, Jun-Qin; Li, Hong-Xia; Chen, Xin-Min; Mo, Feng-Feng; Qi, Rui-Rui; Guo, Jun-Sheng; Cai, Yi-Ling

2012-06-21

126

Visual and vestibular cue integration for heading perception in extrastriate visual cortex.  

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Natural behaviours, and hence neuronal populations, often combine multiple sensory cues to improve stimulus detectability or discriminability as we explore the environment. Here we review one such example of multisensory cue integration in the dorsal medial superior temporal area (MSTd) of the macaque visual cortex. Visual and vestibular cues about the direction of self-motion in the world (heading) are encoded by single multisensory neurons in MSTd. Most neurons tend to prefer lateral stimulus directions and, as they are broadly tuned, are most sensitive in discriminating heading directions around straight forward. Decoding of MSTd population activity shows that these neuronal properties can account for the fact that heading perception in humans and macaques is most precise for directions around straight forward, whereas heading sensitivity declines with increasing eccentricity of the reference direction. Remarkably, when heading is specified by both cues simultaneously, behavioural precision is improved in a manner that is predicted by statistically optimal (Bayesian) cue integration models. A subpopulation of multisensory MSTd cells with congruent visual and vestibular heading preferences also combines the cues near-optimally, establishing a potential neural substrate for behavioral cue integration. PMID:20679353

Angelaki, Dora E; Gu, Yong; Deangelis, Gregory C

2011-02-15

127

Brainstem processing of vestibular sensory exafference: implications for motion sickness etiology.  

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The origin of the internal "sensory conflict" stimulus causing motion sickness has been debated for more than four decades. Recent studies show a subclass of neurons in the vestibular nuclei and deep cerebellar nuclei that respond preferentially to passive head movements. During active movement, the semicircular canal and otolith input ("reafference") to these neurons are canceled by a mechanism comparing the expected consequences of self-generated movement (estimated with an internal model-presumably located in the cerebellum) with the actual sensory feedback. The un-canceled component ("exafference") resulting from passive movement normally helps compensate for unexpected postural disturbances. Notably, the existence of such vestibular "sensory conflict" neurons had been postulated as early as 1982, but their existence and putative role in posture control and motion sickness have been long debated. Here, we review the development of "sensory conflict" theories in relation to recent evidence for brainstem and cerebellar reafference cancelation, and identify some open research questions. We propose that conditions producing persistent activity of these neurons, or their targets, stimulate nearby brainstem emetic centers-via an as yet unidentified mechanism. We discuss how such a mechanism is consistent with the notable difference in motion sickness susceptibility of drivers as opposed to passengers, human immunity to normal self-generated movement and why head restraint or lying horizontal confers relative immunity. Finally, we propose that fuller characterization of these mechanisms and their potential role in motion sickness could lead to more effective, scientifically based prevention and treatment for motion sickness. PMID:24838552

Oman, Charles M; Cullen, Kathleen E

2014-08-01

128

[Changes of glutamate and taurine released in the medial vestibular nucleus following acute hypotension].  

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In order to understand whether some special amino acids in the medial vestibular nucleus (MVN) of rats are involved in the regulation of blood pressure, we used microdialysis technique and high performance liquid chromatography (HPLC) to measure the changes of glutamate and taurine in this central area. Acute hypotension was induced by hemorrhage from the femoral artery. It was observed that the basal release of glutamate and taurine in the MVN was stable about 90 min after the beginning of microdialysis. The basal release of glutamate was (18.96 +/- 0.27) pmol/sample (8 mul), and that of taurine was (7.73 +/- 0.05) pmol/sample (8 mul). Glutamate release increased (Ptympanic cavity. These results suggest that the hemorrhage-induced acute hypotention can influence the activity of the neurons in the MVN by the afferent impulses from vestibular organ, and that some special amino acid transmitters in the MVN are involved in this process. PMID:16628366

Yu, Hai-Ling; An, Ying; Bing, Yan-Hua; Jin, Qing-Hua; Cui, Xun; Jin, Yuan-Zhe

2006-04-25

129

Comparação de diferentes protocolos de reabilitação vestibular em pacientes com disfunções vestibulares periféricas / Comparison of different protocols for vestibular rehabilitation in patients with peripheral vestibular disorders  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: Comparar a eficácia terapêutica de dois protocolos de reabilitação vestibular em diferentes disfunções vestibulares. MÉTODOS: Participaram 20 pacientes com disfunções periféricas crônicas, de ambos os gêneros (prevalência do gênero feminino, com 60% da amostra), com média de idade de 55 an [...] os e 9 meses. O Grupo 1 realizou exercícios baseados na estimulação do reflexo vestíbulocular vertical e horizontal, e o Grupo 2 realizou exercícios baseados em um protocolo de reabilitação vestibular personalizado. A análise de dados levou em consideração a queixa durante a anamnese e a evolução clínica do paciente a partir da execução dos exercícios. Além disso, foram obtidos os resultados do questionário Dizziness Handicap Inventory (DHI) e da escala analógica e visual de tontura (EVA), pré e pós reabilitação vestibular. RESULTADOS: Houve diferença nos valores da EVA e do DHI (escala física, funcional e no valor total), pré e pós-reabilitação vestibular, em ambos os grupos. Porém, na comparação dos dois grupos no momento pós-reabilitação, o Grupo 2 obteve melhores resultados que o Grupo 1, tanto na EVA quanto no DHI (escala funcional e no valor total). CONCLUSÃO: A reabilitação vestibular possibilitou melhora significativa do quadro otoneurológico clínico e na auto-percepção da tontura independentemente da terapêutica empregada. A reabilitação vestibular personalizada mostrou-se mais eficaz do que o protocolo de estimulação do reflexo vestibulocular na melhora da qualidade de vida de indivíduos com disfunções periféricas crônicas Abstract in english PURPOSE: To compare the therapeutic efficacy of two protocols for vestibular rehabilitation in several vestibular disordes. METHODS: Twenty patients with chronic peripheral disorders of both genders (prevalence of females, with 60% of the sample) and mean age of 55 years and 9 months participated in [...] this study. Group 1 carried out exercices based on stimulation of vertical and horizontal vestibulocular reflex, and Group 2 carried out exercices based on a protocol of personalized vestibular rehabilitation. Data analysis considered the complaint manifested during anamnesis and the clinical evolution of the patient during the execution of the exercises. The results obtained from the application of the Dizziness Handicap Inventory questionnaire (DHI) and the dizziness visual analog scale (VAS), both before and after vestibular rehabilitation, were also considered in the analysis. RESULTS: Differences were found in the values obtained in VAS and DHI (physical and functional scales and total score), in both groups. However, the comparison of the groups after rehabilitation showed that Group 2 obtained better scores than Group 1, both in VAS and DHI (functional scale and total value). CONCLUSION: Vestibular rehabilitation allowed significant improvement in otoneurological clinical profile and in self-perception of dizziness, regardless the therapeutic method used. Personalized vestibular rehabilitation was more efficient than the vestibulocular reflex stimulation protocol in improving quality of life of individuals with chronic periferal disorders

Pâmela Garcia, Morozetti; Cristina Freitas, Ganança; Brasília Maria, Chiari.

130

Vestibular Schwannoma or acoustic neuroma  

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Full Text Available Vestibular schwannoma is the most common tumor of the posterior fossa of the skull. Patients referred with the primary otologic symptoms such as hearing loss, tinnitus, vertigo, imbalance, and the cranial nerve palsy. Thirty-three patients were operated and treated by a team of otolaryngologist and neurosurgeon, anudiometrist, and internist. Patients'chiefcomplaint was due to 94% hearing loss and 27% tinnitus. They scarcely complain of vertigo. If a patient refers with the palsy or paralysis of facial nerve preoperation, we must think of the facial nerve schwannoma or hemangioma or congential cholestoma or malignant metastases rather than acoustic neuroma. The best way for preoperative diagnosis is audiometry, ABR (Auditory Brain Response, and SDS (speech discrimination score with 90% success, but computer Tomography (CT scan and MRI (Magnetic Resonance Image are the valuable anatomic diagnostic radiographic devices. The best method of operation is translabirynthine approach (TLA, since it has the advantages such as an easy access to nerve paths and being the nearest path to CPA (Cerebellopontine Angle. Physicians ought to talk to patients about the importance of the microscopic surgery, surgical methods, and their probable diverse effects such as hearing loss, facial nerve palsy, and intracranial problems.

Hekmatara M

1997-04-01

131

Avaliação vestibular em mulheres com disfunção temporomandibular / Vestibular evaluation in women with temporomandibular dysfunction  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: avaliar o comportamento vestibular em pacientes com disfunção temporomandibular. MÉTODOS: avaliaram-se 27 pacientes do sexo feminino, na faixa etária de 30 a 53 anos, encaminhadas do Centro de Diagnóstico e Tratamento da Articulação Temporomandibular para o Laboratório de Otoneurologia da [...] Universidade Tuiuti do Paraná. Realizaram-se os seguintes procedimentos: anamnese, inspeção otológica e avaliação vestibular por meio da vectoeletronistagmografia. RESULTADOS: as queixas mais freqüentes foram: dificuldade ou dor ao movimento do pescoço (77,7%), dor irradiada para ombro/braço (77,7%), zumbido e formigamento de extremidade superior (77,7%), tontura e dor de cabeça (66,6%), ansiedade (55,5%), sensação de cabeça oca (51,8%), agitação durante o sono (51,8%) e depressão (51,8%). O exame vestibular esteve alterado em 20 pacientes (74,0%) na prova calórica. Houve freqüência de alteração no sistema vestibular periférico. Houve predomínio das síndromes vestibulares periféricas deficitárias. CONCLUSÃO: ressalta-se a importância de se estudar a relação do sistema vestibular com a disfunção temporomandibular uma vez que observamos, na presente pesquisa, um número elevado de alteração no exame labiríntico. Abstract in english PURPOSE: to evaluate the vestibular functioning in patients with temporomandibular joint dysfunction. METHODS: 27 female patients were evaluated, with age varying from 30 to 53-year-old, referred from the Centre of Diagnosis and Treatment of Temporomandibular Joint Dysfunction to the Otoneurological [...] Laboratory of Tuiuti University of Paraná. The following exams were carried out: anamnesis, otoscopy and vestibular evaluations through vectoelectronystagmography. RESULTS: the most frequent complaints were: difficulty or pain with movement of the neck (77.7%), pain irradiated to the shoulder/arm (77.7%), tinnitus and paresthesia of superior extremities (77.7%) in each one, dizziness and headaches (66,6%), anxiety (55.5%), empty head sensations, agitation during sleep and depression (51.8%) in each one. The vestibular exam showed alterations in 20 patients (74.0%) in the caloric test. There was a prevalence of alterations in the peripheral vestibular system. There was a prevalence of deficient peripheral vestibular syndrome. CONCLUSION: the importance of studying the relationship between the vestibular system and temporomandibular joint dysfunction is emphasized, since a high number of alterations in the labyrinthic exam have been noted in this research.

Bianca Simone, Zeigelboim; Ari Leon, Jurkiewicz; Jackeline, Martins-Bassetto; Karlin Fabianne, Klagenberg.

132

Diagnóstico e tratamento das principais síndromes vestibulares / Diagnosis and treatment of the most frequent vestibular syndromes  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Os objetivos deste estudo foram identificar as síndromes vestibulares mais comuns nos ambulatórios de vertigem, suas características clínicas e semiológicas, e observar a resposta ao tratamento específico. Foram estudados retrospectivamente 515 pacientes atendidos em ambulatórios de duas instituiçõe [...] s e avaliados aspectos da anamnese, exame físico e a resposta ao tratamento. As síndromes mais freqüentes foram: vertigem de posicionamento paroxística benigna (VPPB) (28,5%), vertigem postural fóbica (11,5%), vertigem central (10,1%), neurite vestibular (9,7%), doença de Menière (8,5%), enxaqueca (6,4%). Houve boa resposta ao tratamento nos pacientes com enxaqueca (78,8%), VPPB (64%), neurite vestibular (62%), doença de Menière (54,5%) e paroxismia vestibular (54,5%), enquanto pacientes com nistagmo para baixo e vestibulopatia bilateral não tiveram resposta satisfatória (52,6% e 42,8% respectivamente). As síndromes vestibulares foram diagnosticadas através da anamnese e exame físico com testes clínicos específicos para avaliação da função vestibular. A identificação destas síndromes permitiu o tratamento adequado levando a uma boa evolução. Abstract in english The aims of this study were to identify the most common vestibular syndromes in a dizziness unit, and to observe their clinical aspects and response to treatment. Five hundred and fifteen patients were studied retrospectively in two institutions. Aspects of anamnesis, physical examination and the re [...] sponse to treatment were evaluated. The most frequent syndromes were: benign paroxysmal positioning vertigo (VPPB) (28.5%), phobic postural vertigo (11.5%), central vertigo (10.1%), vestibular neuritis (9.7%), Menière disease (8.5%), and migraine (6.4%). A good response to treatment was observed in most patients with migraine (78.8%), VPPB (64%), vestibular neuritis (62%), Menière disease (54.5%) and vestibular paroxismia (54.5%). On the other hand, patients with downbeat nystagmus and bilateral vestibulopathy had poor response (52.6% and 42.8%, respectively). The diagnosis of these most frequent vestibular syndromes were established through anamnesis and physical examination (with specific clinical tests for evaluation of the vestibular function). The correct diagnosis and adequate treatment are important since these syndromes may have a good prognosis.

Aline Mizuta Kozoroski, Kanashiro; Cristiana Borges, Pereira; Antonio Carlos de Paiva, Melo; Milberto, Scaff.

2005-03-01

133

Diagnóstico e tratamento das principais síndromes vestibulares / Diagnosis and treatment of the most frequent vestibular syndromes  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Os objetivos deste estudo foram identificar as síndromes vestibulares mais comuns nos ambulatórios de vertigem, suas características clínicas e semiológicas, e observar a resposta ao tratamento específico. Foram estudados retrospectivamente 515 pacientes atendidos em ambulatórios de duas instituiçõe [...] s e avaliados aspectos da anamnese, exame físico e a resposta ao tratamento. As síndromes mais freqüentes foram: vertigem de posicionamento paroxística benigna (VPPB) (28,5%), vertigem postural fóbica (11,5%), vertigem central (10,1%), neurite vestibular (9,7%), doença de Menière (8,5%), enxaqueca (6,4%). Houve boa resposta ao tratamento nos pacientes com enxaqueca (78,8%), VPPB (64%), neurite vestibular (62%), doença de Menière (54,5%) e paroxismia vestibular (54,5%), enquanto pacientes com nistagmo para baixo e vestibulopatia bilateral não tiveram resposta satisfatória (52,6% e 42,8% respectivamente). As síndromes vestibulares foram diagnosticadas através da anamnese e exame físico com testes clínicos específicos para avaliação da função vestibular. A identificação destas síndromes permitiu o tratamento adequado levando a uma boa evolução. Abstract in english The aims of this study were to identify the most common vestibular syndromes in a dizziness unit, and to observe their clinical aspects and response to treatment. Five hundred and fifteen patients were studied retrospectively in two institutions. Aspects of anamnesis, physical examination and the re [...] sponse to treatment were evaluated. The most frequent syndromes were: benign paroxysmal positioning vertigo (VPPB) (28.5%), phobic postural vertigo (11.5%), central vertigo (10.1%), vestibular neuritis (9.7%), Menière disease (8.5%), and migraine (6.4%). A good response to treatment was observed in most patients with migraine (78.8%), VPPB (64%), vestibular neuritis (62%), Menière disease (54.5%) and vestibular paroxismia (54.5%). On the other hand, patients with downbeat nystagmus and bilateral vestibulopathy had poor response (52.6% and 42.8%, respectively). The diagnosis of these most frequent vestibular syndromes were established through anamnesis and physical examination (with specific clinical tests for evaluation of the vestibular function). The correct diagnosis and adequate treatment are important since these syndromes may have a good prognosis.

Aline Mizuta Kozoroski, Kanashiro; Cristiana Borges, Pereira; Antonio Carlos de Paiva, Melo; Milberto, Scaff.

134

Galvanic vestibular stimulation: a novel modulatory countermeasure for vestibular-associated movement disorders / Estimulação galvânica vestibular para corrigir transtornos neurológicos associados à disfunção vestibular  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A cinetose ou doença do movimento resulta de uma resposta neural anormal originada do desequilíbrio entre estímulos visuais, proprioceptivos e vestibulares, que melhora quando esse desequilíbrio é corrigido. A síndrome de adaptação espacial ou doença do espaço está relacionada à doença do movimento [...] e é desencadeada por mudanças bruscas de direção, inclinação e rotação da cabeça. Têm sido propostas várias medidas comportamentais e farmacológicas para controlar esses transtornos do movimento associados com o sistema vestibular, mas sem sucesso. A estimulação galvânica vestibular pode regular o desequilíbrio sensitivo-motor causado pela cinetose e pela doença do espaço modulando os canais iônicos GABA, relacionados à transmissão de impulsos nervosos no ouvido interno. Essa estimulação melhora a relação sinal-ruído dos impulsos proprioceptivos que acabam modulando a resposta motora, restabelecendo o equilíbrio e a marcha, recuperando a desorientação espacial causada pelos diversos gradientes de gravidade. Abstract in english Motion sickness or kinetosis is the result of the abnormal neural output originated by visual, proprioceptive and vestibular mismatch, which reverses once the dysfunctional sensory information becomes coherent. The space adaptation syndrome or space sickness relates to motion sickness; it is conside [...] red to be due to yaw, pith, and roll coordinates mismatch. Several behavioural and pharmacological measures have been proposed to control these vestibular-associated movement disorders with no success. Galvanic vestibular stimulation has the potential of up-regulating disturbed sensory-motor mismatch originated by kinetosis and space sickness by modulating the GABA-related ion channels neural transmission in the inner ear. It improves the signal-to-noise ratio of the afferent proprioceptive volleys, which would ultimately modulate the motor output restoring the disordered gait, balance and human locomotion due to kinetosis, as well as the spatial disorientation generated by gravity transition.

Carlos V., Rizzo-Sierra; Alexander, Gonzalez-Castaño; Fidias E., Leon-Sarmiento.

2014-01-01

135

VESTIBULAR NASAL STENOSIS. A clinical case  

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Full Text Available Iatrogenic vestibular stenosis is a blockage of the nasal vestibule caused by adisruption of the vestibular lining with secondary proliferation of fibrous tissue scar and granulation. It is more common as a result of foreign body reaction or nasal trauma. The lesions usually include the lobby and the anterior inferior turbinate. We report the case of a girl of eleven, with a complete and recurrent stenosis of the right nasal vestibule, and whose history was spent in the incubator at birth and feeding tube during this period with repeated aspirations traumatic nostril.

A. Fernández Rodríguez

2010-01-01

136

Virtual Neuron  

Science.gov (United States)

Neurons are able to communicate with each other using biochemicals called neurotransmitters. Use Virtual Neuron to explore neurotransmitter properties, make neurons fire, and manipulate neural circuits.

2009-04-14

137

THE DINAMICS OF IMPULSE ACTIVITY OF THE INFERIOR VESTIBULAR NUCLEUS UNDER CONDITIONS OF VIBRATION IN LABYRINTHECTOMIED RATS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The computer analyzes of the inferior vestibular nuclei was performed in norm and after unilateral labyrinthactomy of right site. On 2-d day after oparation, animals were vibrated with diferent period (5, 10 and 15 days). Benchmark analysis of the features of background pulse activity of both nuclei neurons showed initial asymmetry of the impulse average frequency and factor of variation of interspike intervals. It was showed, that after 5 days vibration average frequency of Roller’s both ...

S G Sargsyan, I. B. Meliksetyan

2010-01-01

138

Towards a concept of disorders of “higher vestibular function”  

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Full Text Available Background: Vestibular disorders are commonly characterized by a combination of perceptual, ocular motor, postural, and vegetative manifestations, which cause the symptoms of vertigo, nystagmus, ataxia, and nausea. Multisensory convergence and numerous polysynaptic pathways link the bilaterally organized central vestibular network with limbic, hippocampal, cerebellar, and non-vestibular cortex structures to mediate “higher” cognitive functions. Anatomical classification of vestibular disorders: The traditional classification of vestibular disorders is based on the anatomical site of the lesion. While it distinguishes between the peripheral and the central vestibular systems, certain weaknesses become apparent when applied clinically. There are two reasons for this: first, peripheral and central vestibular disorders cannot always be separated by the clinical syndrome; second, a third category, namely disorders of “higher vestibular function”, is missing. These disorders may be caused by peripheral as well as central vestibular lesions. Functional classification: Here we discuss a new concept of disorders of higher vestibular function which involve cognition and more than one sensory modality. Three conditions are described that exemplify such higher disorders: room tilt illusion, spatial hemineglect, and bilateral vestibulopathy all of which present with deficits of orientation and spatial memory. Conclusions: Further elaboration of such disorders of higher multisensory functions with respect to lesion site and symptomatology is desirable. The room tilt illusion and spatial hemineglect involve vestibular and visual function to the extent that both conditions can be classified as either disorders of higher vestibular or of higher visual functions. A possible way of separating these disorders in a first step is to determine whether the causative lesion site affects the vestibular or the visual system. For the vestibular system this lesion site may be peripheral o

Michael Strupp

2014-06-01

139

Perspectives in vestibular diagnostics and therapy [  

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Full Text Available [english] Vestibular diagnostics and therapy ist the mirror of technological, scientific and socio-economics trends as are other fields of clinical medicine. These trends have led to a substantial diversification of the field of neurotology.The improvements in diagnostics have been characterized by the introduction of new receptor testing tools (e.g., VEMPs, progress in imaging (e.g., the endolymphatic hydrops and in the description of central-vestibular neuroplasticity. The etiopathology of vestibular disorders has been updated by geneticists (e.g., the description of the COCH gene mutations, the detection of structural abnormalities (e.g., dehiscence syndromes and related disorders (e.g. migraine-associated vertigo. The therapeutic options were extended by re-evaluation of techniques known a long time ago (e.g., saccus exposure, the development of new approaches (e.g., dehiscence repair and the introduction of new drug therapy concepts (e.g., local drug delivery. Implantable, neuroprosthetic solutions have not yet reached experimental safety and validity and are still far away. However, externally worn neuroprosthetic solution were introduced in the rehab of vestibular disorders (e.g., VertiGuard system.These and related trends point into a medical future which is characterized by presbyvertigo as classical sign of the demographic changes ahead, by shortage of financial resources and a medico-legally over-regulated, even hostile environment for physicians in clinical medicine.

Ernst, Arneborg

2012-04-01

140

Perspectives in vestibular diagnostics and therapy.  

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Vestibular diagnostics and therapy ist the mirror of technological, scientific and socio-economics trends as are other fields of clinical medicine. These trends have led to a substantial diversification of the field of neurotology.The improvements in diagnostics have been characterized by the introduction of new receptor testing tools (e.g., VEMPs), progress in imaging (e.g., the endolymphatic hydrops) and in the description of central-vestibular neuroplasticity. The etiopathology of vestibular disorders has been updated by geneticists (e.g., the description of the COCH gene mutations), the detection of structural abnormalities (e.g., dehiscence syndromes) and related disorders (e.g. migraine-associated vertigo). The therapeutic options were extended by re-evaluation of techniques known a long time ago (e.g., saccus exposure), the development of new approaches (e.g., dehiscence repair) and the introduction of new drug therapy concepts (e.g., local drug delivery). Implantable, neuroprosthetic solutions have not yet reached experimental safety and validity and are still far away. However, externally worn neuroprosthetic solution were introduced in the rehab of vestibular disorders (e.g., VertiGuard system).These and related trends point into a medical future which is characterized by presbyvertigo as classical sign of the demographic changes ahead, by shortage of financial resources and a medico-legally over-regulated, even hostile environment for physicians in clinical medicine. PMID:22558055

Ernst, Arneborg

2011-01-01

 
 
 
 
141

Recovery of gaze stability during vestibular regeneration.  

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Many motion related behaviors, such as gaze stabilization, balance, orientation, and navigation largely depend on a properly functioning vestibular system. After vestibular insult, many of these responses are compromised but can return during the regeneration of vestibular receptors and afferents as is known to occur in birds, reptiles, and amphibians. Here we characterize gaze stability in pigeons to rotational motion during regeneration after complete bilateral vestibular loss via an ototoxic antibiotic. Immediate postlesion effects included severe head oscillations, postural ataxia, and total lack of gaze control. We found that these abnormal behaviors gradually subsided, and gaze stability slowly returned to normal function according to a temporal sequence that lasted several months. We also found that the dynamic recovery of gaze function during regeneration was not homogeneous for all types of motion. Instead high-frequency motion stability was first achieved, followed much later by slow movement stability. In addition, we found that initial gaze stability was established using almost exclusive head-response components with little eye-movement contribution. However, that trend reversed as recovery progressed so that when gaze stability was complete, the eye component had increased and the head response had decreased to levels significantly different from that observed in normal birds. This was true even though the head-fixed VOR response recovered normally. Recovery of gaze stability coincided well with the three stage temporal sequence of morphologic regeneration previously described by our laboratory. PMID:18045999

Haque, Asim; Zakir, Mridha; Dickman, J David

2008-02-01

142

Vestibular evoked myogenic potentials in Bell's palsy.  

Science.gov (United States)

The aim of the present study was to evaluate vestibular nerve involvement in patients with Bell's palsy with ocular and cervical vestibular evoked myogenic potentials (oVEMP and cVEMP). Ten patients who were diagnosed with Bell's palsy and ten healthy controls were included. All patients underwent VEMP recordings within 6 days after their initial presentation. Patients with Bell's palsy had greater oVEMP asymmetry ratio comparing to healthy controls (-38.4 ± 28.7 % vs -1.3 ± 19.3 %, p = 0.005). As well N10 latencies of the oVEMP response were prolonged comparing to healthy controls (11.575 vs 9.72 ms). There was no difference in cVEMP asymmetry ratio or latencies between groups. We found no correlation between House-Brackmann grading scale and oVEMP asymmetry ratio (r = 0.003, p = 0.994). There are three possible explanations for increased oVEMP amplitudes on the affected side: (1) oVEMP response on the ipsilateral eye could be contaminated by facial nerve activity (blink reflex); (2) the amplitude of N10-P33 could be affected through the stapedial reflex; and (3) increased oVEMP amplitude could be the consequence of the vestibular nerve dysfunction itself, with prolonged latencies of the N10 oVEMP further supporting this explanation. The results of this study indicate possible involvement of the superior branch of the vestibular nerve in patients with Bell's palsy. PMID:24916836

Krbot Skoric, Magdalena; Adamec, Ivan; Habek, Mario

2014-10-01

143

Vesibulotoxicity and Management of Vestibular Disorders  

Science.gov (United States)

The toxicity of certain aminoglycoside antibiotics for vestibular hair cells has been used to special advantage in the treatment of Meniere's disease. Intratympanic (middle ear) injections of these drugs are being increasingly used to control vertigo in this disorder when it has not responded to medical therapy. The mechanisms by which these drugs…

Carey, John P.

2005-01-01

144

Evaluation of postural control in unilateral vestibular hypofunction / Avaliação do controle postural na hipofunção vestibular unilateral  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese INTRODUÇÃO: Pacientes com hipofunção vestibular, achado típico em vestibulopatias periféricas, apresentam alterações de equilíbrio corporal. OBJETIVO: Avaliar o controle postural de pacientes vertiginosos com hipofunção vestibular unilateral. MÉTODO: Trata-se de um estudo clínico transvers [...] al. No total, 25 pacientes vertiginosos com hipofunção vestibular unilateral e um grupo controle homogêneo de 32 indivíduos hígidos foram submetidos à avaliação otoneurológica, incluindo a posturografia do Tetrax Interactive Balance System em oito diferentes condições sensoriais. RESULTADOS: O grupo experimental apresentou valores significantemente maiores do que o grupo controle quanto ao índice de estabilidade geral, índice de distribuição de peso, índice de sincronização da oscilação postural direita/esquerda e dedos/calcanhar, faixas de frequência de oscilação postural (F1, F2-F4, F5-F6, F7-F8) e índice de risco de queda, em diferentes condições sensoriais. CONCLUSÃO: Alterações de distribuição de peso, sincronização da oscilação postural direita/esquerda e dedos/calcanhares, faixas de frequência de oscilação postural e do índice de risco de queda caracterizam o comprometimento do controle postural em pacientes vertiginosos com hipofunção vestibular unilateral. Abstract in english INTRODUCTION: Patients with vestibular hypofunction, a typical finding in peripheral vestibular disorders, show body balance alterations. OBJECTIVE: To evaluate the postural control of patients with vertigo and unilateral vestibular hypofunction. METHOD: This is a clinical cross-sectional [...] study. Twenty-five patients with vertigo and unilateral vestibular hypofunction and a homogeneous control group consisting of 32 healthy individuals were submitted to a neurotological evaluation including the Tetrax Interactive Balance System posturography in eight different sensory conditions. RESULTS: For different positions, vertiginous patients with unilateral vestibular hypofunction showed significantly higher values of general stability index, weight distribution index, right/left and tool/heel synchronizations, Fourier transformation index and fall index than controls. CONCLUSION: Increased values in the indices of weight distribution, right/left and tool/heel synchronizations, Fourier transformation and fall risk characterize the impairment of postural control in patients with vertigo and unilateral vestibular hypofunction.

Rafaela Maia, Quitschal; Jackeline Yumi, Fukunaga; Maurício Malavasi, Ganança; Heloísa Helena, Caovilla.

2014-07-01

145

Evaluation of postural control in unilateral vestibular hypofunction / Avaliação do controle postural na hipofunção vestibular unilateral  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese INTRODUÇÃO: Pacientes com hipofunção vestibular, achado típico em vestibulopatias periféricas, apresentam alterações de equilíbrio corporal. OBJETIVO: Avaliar o controle postural de pacientes vertiginosos com hipofunção vestibular unilateral. MÉTODO: Trata-se de um estudo clínico transvers [...] al. No total, 25 pacientes vertiginosos com hipofunção vestibular unilateral e um grupo controle homogêneo de 32 indivíduos hígidos foram submetidos à avaliação otoneurológica, incluindo a posturografia do Tetrax Interactive Balance System em oito diferentes condições sensoriais. RESULTADOS: O grupo experimental apresentou valores significantemente maiores do que o grupo controle quanto ao índice de estabilidade geral, índice de distribuição de peso, índice de sincronização da oscilação postural direita/esquerda e dedos/calcanhar, faixas de frequência de oscilação postural (F1, F2-F4, F5-F6, F7-F8) e índice de risco de queda, em diferentes condições sensoriais. CONCLUSÃO: Alterações de distribuição de peso, sincronização da oscilação postural direita/esquerda e dedos/calcanhares, faixas de frequência de oscilação postural e do índice de risco de queda caracterizam o comprometimento do controle postural em pacientes vertiginosos com hipofunção vestibular unilateral. Abstract in english INTRODUCTION: Patients with vestibular hypofunction, a typical finding in peripheral vestibular disorders, show body balance alterations. OBJECTIVE: To evaluate the postural control of patients with vertigo and unilateral vestibular hypofunction. METHOD: This is a clinical cross-sectional [...] study. Twenty-five patients with vertigo and unilateral vestibular hypofunction and a homogeneous control group consisting of 32 healthy individuals were submitted to a neurotological evaluation including the Tetrax Interactive Balance System posturography in eight different sensory conditions. RESULTS: For different positions, vertiginous patients with unilateral vestibular hypofunction showed significantly higher values of general stability index, weight distribution index, right/left and tool/heel synchronizations, Fourier transformation index and fall index than controls. CONCLUSION: Increased values in the indices of weight distribution, right/left and tool/heel synchronizations, Fourier transformation and fall risk characterize the impairment of postural control in patients with vertigo and unilateral vestibular hypofunction.

Rafaela Maia, Quitschal; Jackeline Yumi, Fukunaga; Maurício Malavasi, Ganança; Heloísa Helena, Caovilla.

146

Vestibular characterization in the menstrual cycle / Caracterização vestibular no ciclo menstrual  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese As alterações hormonais do ciclo menstrual podem comprometer a homeostase dos fluidos labirínticos, gerando alterações no equilíbrio e na audição. FORMA DO ESTUDO: Clínico prospectivo. OBJETIVO: Comparar os resultados dos testes do exame vestibular em mulheres jovens, nos períodos pré e pós-menstrua [...] l. MATERIAL E MÉTODO: Foram selecionadas vinte mulheres, entre dezoito e trinta e cinco anos, que não fizessem uso de qualquer tipo de anticoncepcional, com audição normal e sem queixas vestibulares. O exame vestibular foi realizado em cada participante no período pré e no período pós-menstrual, em ordem aleatória, e respeitando o limite de até dez dias antes do início da menstruação e até dez dias após o início da menstruação. RESULTADO: Foi observada a presença de diferença estatisticamente significante no ciclo ovariano somente para as provas do exame vestibular de calibração, movimentos sacádicos, prova rotatória pendular decrescente e prova calórica. As variáveis: idade, ciclo menstrual regulado, casos de surdez ou tontura na família, doenças anteriores, e sintomas do período pré-menstrual como zumbido, cefaleia, distúrbio do sono, ansiedade, náusea e hiperacusia também podem interferir no exame otoneurológico. CONCLUSÃO: Há diferenças nos resultados do exame vestibular em mulheres sadias entre os períodos pré e pós menstrual. Abstract in english Hormonal disorders in the menstrual cycle can affect labyrinthine fluid homeostasis, causing balance and hearing dysfunctions. STUDY DESIGN: Clinical prospective. AIM: compare the results from vestibular tests in young women, in the premenstrual and postmenstrual periods. MATERIALS AND METHODS: twen [...] ty women were selected with ages ranging from 18 to 35 years, who were not using any kind of contraceptive method for at least six months, and without vestibular or hearing complaints. The test was carried out in each subject before and after the menstrual period, respecting the limit of ten days before or after menstruation. RESULTS: there was a statistically significant difference in the menstrual cycle phases only in the following vestibular tests: calibration, saccadic movements, PRPD and caloric-induced nystagmus. We also noticed that age; a regular menstrual cycle; hearing loss or dizziness cases in the family; and premenstrual symptoms such as tinnitus, headache, sleep disorders, anxiety, nausea and hyperacusis can interfere in the vestibular test. CONCLUSION: there are differences in the vestibular tests of healthy women when comparing their pre and postmenstrual periods.

Cintia, Ishii; Lucia Kazuko, Nishino; Carlos Alberto Herrerias de, Campos.

2009-06-01

147

Descripción, interpretación, análisis e importancia del nistagmus inducido por la hiperventilación en el estudio de patologías vestibulares periféricas y centrales / Description, interpretation, analysis and importance of hyperventilation -induced nystagmus in the study of the peripheral and central vestibular disorders  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Recientes estudios clínicos han revelado la utilidad del test del nistagmus inducido por la hiperventilación aguda, en la investigación de patologías vestibulares retrolaberínticas, neurales y de origen central, con la aparición de nistagmus paréticos o bien excitatorios. El propósito de este estudi [...] o ha sido: primero, conocer la sensibilidad de este examen según el análisis de los estudios de diferentes autores; segundo, entender la fisiopatología de este nistagmus inducido por la hiperventilación y tercero, efectuar una interpretación y análisis de este examen que permita obtener conclusiones sólidas del mejor nivel de medicina basada en evidencias. Para efectuar este estudio y análisis se procedió a una investigación exhaustiva de las publicaciones sobre el tema en los últimos 25 años, recurriendo para ello como fuentes de información a las principales bases de datos biomédicos y a la revisión en texto completo de estas publicaciones. Llamó la atención la escasez de trabajos clínicos publicados sobre el tema que no superan los 40, y también la escasez de trabajos sobre la fisiopatología del nistagmus inducido por la hiperventilación aguda. La metódica del test es muy simple por lo que su utilización resulta muy atractiva, con un escaso número de falsos positivos. La mayor parte de los estudios publicados, se focaliza en su utilización en el schwanoma vestibularyen la neuronitis vestibular. Respecto al schwanoma vestibular de un total de 107 pacientes estudiados el test fue positivo en el 80% de los casos, con aparición de nistagmus ipsilesional o contralesional. En la neuronitis vestibular la positividad del test alcanzó a 60°% de un total de 272 pacientes estudiados y que estaba en relación directa con el tiempo de evolución de la enfermedad. En la esclerosis múltiple, en pacientes con síntomas vestibulares, la positividad del test fue de 75°%, en cambio en aquellos pacientes sin síntomas vestibulares la positividad fue de sólo 7°%. En las enfermedades cerebelosas, particularmente las degenerativas, la positividad de este test fue de 78°%. La pesquisa del nistagmus inducido por la hiperventilación, fue una prueba poco significativa estadísticamente, en otras patologías vestibulares períféricas tales como la enfermedad de Ménière o el VPPB, así como en otras enfermedades vestibulares centrales, salvo las de origen vascular por insuficiencia del sistema vértebro-basilar. El estudio y análisis de las publicaciones sobre el nistagmus inducido por la hiperventilación aguda, permite concluir que es un test de fácil realización; que ante la sospecha de un schwanoma vestibular, orienta en el estudio de aquellos pacientes que requieran un estudio de R.M. Que ayuda en el diagnóstico diferencial de una neuronitisvestibular y finalmente que permite en lesiones vestibulares centrales particularmente degenerativas y vasculares un estudio más profundo y adecuado de estos pacientes. Abstract in english Recent clinical studies have revealed the usefulness of the hyperventilation-induced nystagmus in retrolabyrinthine and central vestibular diseases with the appearance either excitatory (ipsilateral) or paretic (contralateral) nystagmus. The objectives of this study have been: 1) to get to know the [...] sensitivity of the exam, according to the best literature available; 2) to get to know the physiopathology of this hyperventilation-induced nystagmus, and 3) to carry out an analysis and interpretation of this exam in order to reach solid conclusions of the highest level in evidence based medicine. An exhaustive research of literature published on this topic in the last 25 years was carried out. The main source of information being the most important medical data-based publications and also a thorough revision of these texts. The scarce number of publications on this topic (not more than 40) is what strikes the attention most, as well as the very few studies of the physiopathology of the hyperventi

Alejandro, Peña M.

2012-04-01

148

Descripción, interpretación, análisis e importancia del nistagmus inducido por la hiperventilación en el estudio de patologías vestibulares periféricas y centrales Description, interpretation, analysis and importance of hyperventilation -induced nystagmus in the study of the peripheral and central vestibular disorders  

Directory of Open Access Journals (Sweden)

Full Text Available Recientes estudios clínicos han revelado la utilidad del test del nistagmus inducido por la hiperventilación aguda, en la investigación de patologías vestibulares retrolaberínticas, neurales y de origen central, con la aparición de nistagmus paréticos o bien excitatorios. El propósito de este estudio ha sido: primero, conocer la sensibilidad de este examen según el análisis de los estudios de diferentes autores; segundo, entender la fisiopatología de este nistagmus inducido por la hiperventilación y tercero, efectuar una interpretación y análisis de este examen que permita obtener conclusiones sólidas del mejor nivel de medicina basada en evidencias. Para efectuar este estudio y análisis se procedió a una investigación exhaustiva de las publicaciones sobre el tema en los últimos 25 años, recurriendo para ello como fuentes de información a las principales bases de datos biomédicos y a la revisión en texto completo de estas publicaciones. Llamó la atención la escasez de trabajos clínicos publicados sobre el tema que no superan los 40, y también la escasez de trabajos sobre la fisiopatología del nistagmus inducido por la hiperventilación aguda. La metódica del test es muy simple por lo que su utilización resulta muy atractiva, con un escaso número de falsos positivos. La mayor parte de los estudios publicados, se focaliza en su utilización en el schwanoma vestibularyen la neuronitis vestibular. Respecto al schwanoma vestibular de un total de 107 pacientes estudiados el test fue positivo en el 80% de los casos, con aparición de nistagmus ipsilesional o contralesional. En la neuronitis vestibular la positividad del test alcanzó a 60°% de un total de 272 pacientes estudiados y que estaba en relación directa con el tiempo de evolución de la enfermedad. En la esclerosis múltiple, en pacientes con síntomas vestibulares, la positividad del test fue de 75°%, en cambio en aquellos pacientes sin síntomas vestibulares la positividad fue de sólo 7°%. En las enfermedades cerebelosas, particularmente las degenerativas, la positividad de este test fue de 78°%. La pesquisa del nistagmus inducido por la hiperventilación, fue una prueba poco significativa estadísticamente, en otras patologías vestibulares períféricas tales como la enfermedad de Ménière o el VPPB, así como en otras enfermedades vestibulares centrales, salvo las de origen vascular por insuficiencia del sistema vértebro-basilar. El estudio y análisis de las publicaciones sobre el nistagmus inducido por la hiperventilación aguda, permite concluir que es un test de fácil realización; que ante la sospecha de un schwanoma vestibular, orienta en el estudio de aquellos pacientes que requieran un estudio de R.M. Que ayuda en el diagnóstico diferencial de una neuronitisvestibular y finalmente que permite en lesiones vestibulares centrales particularmente degenerativas y vasculares un estudio más profundo y adecuado de estos pacientes.Recent clinical studies have revealed the usefulness of the hyperventilation-induced nystagmus in retrolabyrinthine and central vestibular diseases with the appearance either excitatory (ipsilateral or paretic (contralateral nystagmus. The objectives of this study have been: 1 to get to know the sensitivity of the exam, according to the best literature available; 2 to get to know the physiopathology of this hyperventilation-induced nystagmus, and 3 to carry out an analysis and interpretation of this exam in order to reach solid conclusions of the highest level in evidence based medicine. An exhaustive research of literature published on this topic in the last 25 years was carried out. The main source of information being the most important medical data-based publications and also a thorough revision of these texts. The scarce number of publications on this topic (not more than 40 is what strikes the attention most, as well as the very few studies of the physiopathology of the hyperventilation-induced nystagmus. The method of the test is a simple one; this fact makes its applica

Alejandro Peña M

2012-04-01

149

Descripción, interpretación, análisis e importancia del nistagmus inducido por la hiperventilación en el estudio de patologías vestibulares periféricas y centrales / Description, interpretation, analysis and importance of hyperventilation -induced nystagmus in the study of the peripheral and central vestibular disorders  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Recientes estudios clínicos han revelado la utilidad del test del nistagmus inducido por la hiperventilación aguda, en la investigación de patologías vestibulares retrolaberínticas, neurales y de origen central, con la aparición de nistagmus paréticos o bien excitatorios. El propósito de este estudi [...] o ha sido: primero, conocer la sensibilidad de este examen según el análisis de los estudios de diferentes autores; segundo, entender la fisiopatología de este nistagmus inducido por la hiperventilación y tercero, efectuar una interpretación y análisis de este examen que permita obtener conclusiones sólidas del mejor nivel de medicina basada en evidencias. Para efectuar este estudio y análisis se procedió a una investigación exhaustiva de las publicaciones sobre el tema en los últimos 25 años, recurriendo para ello como fuentes de información a las principales bases de datos biomédicos y a la revisión en texto completo de estas publicaciones. Llamó la atención la escasez de trabajos clínicos publicados sobre el tema que no superan los 40, y también la escasez de trabajos sobre la fisiopatología del nistagmus inducido por la hiperventilación aguda. La metódica del test es muy simple por lo que su utilización resulta muy atractiva, con un escaso número de falsos positivos. La mayor parte de los estudios publicados, se focaliza en su utilización en el schwanoma vestibularyen la neuronitis vestibular. Respecto al schwanoma vestibular de un total de 107 pacientes estudiados el test fue positivo en el 80% de los casos, con aparición de nistagmus ipsilesional o contralesional. En la neuronitis vestibular la positividad del test alcanzó a 60°% de un total de 272 pacientes estudiados y que estaba en relación directa con el tiempo de evolución de la enfermedad. En la esclerosis múltiple, en pacientes con síntomas vestibulares, la positividad del test fue de 75°%, en cambio en aquellos pacientes sin síntomas vestibulares la positividad fue de sólo 7°%. En las enfermedades cerebelosas, particularmente las degenerativas, la positividad de este test fue de 78°%. La pesquisa del nistagmus inducido por la hiperventilación, fue una prueba poco significativa estadísticamente, en otras patologías vestibulares períféricas tales como la enfermedad de Ménière o el VPPB, así como en otras enfermedades vestibulares centrales, salvo las de origen vascular por insuficiencia del sistema vértebro-basilar. El estudio y análisis de las publicaciones sobre el nistagmus inducido por la hiperventilación aguda, permite concluir que es un test de fácil realización; que ante la sospecha de un schwanoma vestibular, orienta en el estudio de aquellos pacientes que requieran un estudio de R.M. Que ayuda en el diagnóstico diferencial de una neuronitisvestibular y finalmente que permite en lesiones vestibulares centrales particularmente degenerativas y vasculares un estudio más profundo y adecuado de estos pacientes. Abstract in english Recent clinical studies have revealed the usefulness of the hyperventilation-induced nystagmus in retrolabyrinthine and central vestibular diseases with the appearance either excitatory (ipsilateral) or paretic (contralateral) nystagmus. The objectives of this study have been: 1) to get to know the [...] sensitivity of the exam, according to the best literature available; 2) to get to know the physiopathology of this hyperventilation-induced nystagmus, and 3) to carry out an analysis and interpretation of this exam in order to reach solid conclusions of the highest level in evidence based medicine. An exhaustive research of literature published on this topic in the last 25 years was carried out. The main source of information being the most important medical data-based publications and also a thorough revision of these texts. The scarce number of publications on this topic (not more than 40) is what strikes the attention most, as well as the very few studies of the physiopathology of the hyperventi

Alejandro, Peña M.

150

Swimming Behavior and Calcium Incorporation into inner Ear Otoliths of Fish after vestibular Nerve Transection  

Science.gov (United States)

Previous investigations on neonate swordtail fish (Xiphophorus helleri) revealed that otolithic calcium incorporation (visualized using the calcium-tracer alizarin- complexone) and thus otolith growth had ceased after nerve transection, supporting a hypothesis according to which the gravity-dependent otolith growth is regulated neuronally. Subsequent investigations on larval cichlid fish (Oreochromis mossambicus) yielded contrasting results, repeatedly depending on the particular batch of cichlids investigated: Like neonate swordtails, type I cichlids revealed a stop of calcium incorporation after unilateral vestibular nerve transection. Their behaviour after transection was normal and the otolithic calcium incorporation in controls of the same batch was symmetrical. In type II cichlids, however, vestibular nerve transection had no effect on otolithic calcium incorporation. They behaved kinetotically after transection (this kind of kinetosis was qualitatively similar to the swimming behaviour exhibited by larval cichlids during microgravity in the course of parabolic aircraft flights). The otolithic calcium incorporation in control animals was asymmetrical. These results stongly suggest that the effects of vestibular nerve transection as well as the efficacy of the mechanism, which regulates otolith growth/otolithic calcium incorporation, are - depending on the particular batch of animals - genetically predispositioned. Thus, it is assumed that the mechanisms regulating otolith growth and equlibibrium differ in the two types of cichlid fish. This work was financially supported by the German Aerospace Center (DLR) e.V. (FKZ: 50 WB 9997).

Edelmann, E.; Anken, R.; Rahmann, H.

151

Vestibular loss and balance training cause similar changes in human cerebral white matter fractional anisotropy.  

Science.gov (United States)

Patients with bilateral vestibular loss suffer from severe balance deficits during normal everyday movements. Ballet dancers, figure skaters, or slackliners, in contrast, are extraordinarily well trained in maintaining balance for the extreme balance situations that they are exposed to. Both training and disease can lead to changes in the diffusion properties of white matter that are related to skill level or disease progression respectively. In this study, we used diffusion tensor imaging (DTI) to compare white matter diffusivity between these two study groups and their age- and sex-matched controls. We found that vestibular patients and balance-trained subjects show a reduction of fractional anisotropy in similar white matter tracts, due to a relative increase in radial diffusivity (perpendicular to the main diffusion direction). Reduced fractional anisotropy was not only found in sensory and motor areas, but in a widespread network including long-range connections, limbic and association pathways. The reduced fractional anisotropy did not correlate with any cognitive, disease-related or skill-related factors. The similarity in FA between the two study groups, together with the absence of a relationship between skill or disease factors and white matter changes, suggests a common mechanism for these white matter differences. We propose that both study groups must exert increased effort to meet their respective usual balance requirements. Since balance training has been shown to effectively reduce the symptoms of vestibular failure, the changes in white matter shown here may represent a neuronal mechanism for rehabilitation. PMID:24776524

Hummel, Nadine; Hüfner, Katharina; Stephan, Thomas; Linn, Jennifer; Kremmyda, Olympia; Brandt, Thomas; Flanagin, Virginia L

2014-01-01

152

Vestibular Loss and Balance Training Cause Similar Changes in Human Cerebral White Matter Fractional Anisotropy  

Science.gov (United States)

Patients with bilateral vestibular loss suffer from severe balance deficits during normal everyday movements. Ballet dancers, figure skaters, or slackliners, in contrast, are extraordinarily well trained in maintaining balance for the extreme balance situations that they are exposed to. Both training and disease can lead to changes in the diffusion properties of white matter that are related to skill level or disease progression respectively. In this study, we used diffusion tensor imaging (DTI) to compare white matter diffusivity between these two study groups and their age- and sex-matched controls. We found that vestibular patients and balance-trained subjects show a reduction of fractional anisotropy in similar white matter tracts, due to a relative increase in radial diffusivity (perpendicular to the main diffusion direction). Reduced fractional anisotropy was not only found in sensory and motor areas, but in a widespread network including long-range connections, limbic and association pathways. The reduced fractional anisotropy did not correlate with any cognitive, disease-related or skill-related factors. The similarity in FA between the two study groups, together with the absence of a relationship between skill or disease factors and white matter changes, suggests a common mechanism for these white matter differences. We propose that both study groups must exert increased effort to meet their respective usual balance requirements. Since balance training has been shown to effectively reduce the symptoms of vestibular failure, the changes in white matter shown here may represent a neuronal mechanism for rehabilitation. PMID:24776524

Hummel, Nadine; Hüfner, Katharina; Stephan, Thomas; Linn, Jennifer; Kremmyda, Olympia; Brandt, Thomas; Flanagin, Virginia L.

2014-01-01

153

El examen vestibular abreviado, descripción, interpretación y análisis / The abbreviated vestibular exam, description, interpretation and analysis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Introducción: En el examen vestibular de un paciente vertiginoso juegan un rol muy importante las pruebas calóricas, pero la realización de éstas, unida a las nuevas pruebas que ha traído el avance tecnológico y computacional de la medicina, ha significado que el examen vestibular se ha convertido e [...] n la práctica diaria en un estudio muy largo y oneroso, por tal motivo parece útil la realización de un examen vestibular abreviado preliminar hecho en la misma consulta del médico que permita dar una orientación diagnóstica de bases sólidas. Objetivos: El propósito de este estudio es la descripción, interpretación y análisis crítico del llamado "examen vestibular de 10 minutos del paciente mareado"y que permita llegar a conclusiones sobre la sensibilidad y especificidad de este examen abreviado. Material y método: En este estudio, se describen, interpretan y analizan, según la información bibliográfica disponible, particularmente aquellos estudios de la medicina basada en evidencias las siguientes pruebas propuestas en el examen vestibular abreviado: Búsqueda del nistagmus espontáneo, búsqueda del nistagmus de mirada excéntrica, estudio de los movimientos oculares lentos o de rastreo ocular, estudio de los movimientos oculares rápidos o sacadas, test de Halmagyi, test de agitación cefálica, test de agudeza visual dinámica, test de inhibición de la fijación del nistagmus, maniobra de Dix y Hallpike, test de otoscopía neumática, estudio cerebeloso, estudio de la sensibilidad profunda, prueba de Romberg y estudio de la marcha. Debido a que varias de estas pruebas se efectúan en la prueba vestibular clásica sólo se analizan y discuten aquellas que no se efectúan de rutina en este examen. Resultados: Las pruebas analizadas del examen vestibular abreviado revelan en su gran mayoría baja sensibilidad, menor de 50%, pero una buena especificidad. Con algún entrenamiento básico son fáciles de realizar y requieren poco tiempo para su ejecución pero sí, mucho más que 10 minutos. Discusión: Considerando el largo tiempo que requiere el especialista para efectuar un examen vestibular completo, un estudio básico resulta necesario para orientar la investigación clínica de un paciente vertiginoso. Las pruebas propuestas en este examen, tienen baja sensibilidad consideradas individualmente, pero la realización de todas ellas en su conjunto, le confiere al estudio una gran fortaleza y credibilidad, esto necesariamente unido a una muy buena anamnesis con cuestionario estructurado preestablecido. Conclusiones: El examen vestibular abreviado es un buen estudio, en que si bien las diferentes pruebas tienen baja sensibilidad, el resultado de la suma de todas ellas le confiere al examen una buena confiabilidad. Para su realización es indispensable un buen manejo de las pruebas y un buen conocimiento de la otoneurología por parte del examinador para su correcta interpretación. No existen estudios de medicina basada en evidencias de nivel 1 ó 2 que le otorguen alta credibilidad a estas pruebas. Este examen no debe reemplazar al examen vestibular clásico o formal, incluyendo las pruebas calóricas bi-termales, sino que deben ser consideradas como un estudio básico que permite orientar al especialista para tomar decisiones apropiadas diagnósticas y terapéuticas. Abstract in english Introduction: Caloric tests play a very important role in a patient's vestibular exam. But these exams, along with the new test brought about by both technology and computing in Medicine, have turned these examinations into very long and expensive procedures. Taking all this into account, it seems s [...] uitable the realization of a preliminary vestibular exam performed in the doctor's consultation office. This will allow a diagnostic guideline with solid foundations. Aim: To describe, interpret, and carry out a critical analysis of the so called "10 minute vestibular examination of the dizzy patient" in order to get to some conclusions abou

Alejandro, Peña M.

154

El examen vestibular abreviado, descripción, interpretación y análisis The abbreviated vestibular exam, description, interpretation and analysis  

Directory of Open Access Journals (Sweden)

Full Text Available Introducción: En el examen vestibular de un paciente vertiginoso juegan un rol muy importante las pruebas calóricas, pero la realización de éstas, unida a las nuevas pruebas que ha traído el avance tecnológico y computacional de la medicina, ha significado que el examen vestibular se ha convertido en la práctica diaria en un estudio muy largo y oneroso, por tal motivo parece útil la realización de un examen vestibular abreviado preliminar hecho en la misma consulta del médico que permita dar una orientación diagnóstica de bases sólidas. Objetivos: El propósito de este estudio es la descripción, interpretación y análisis crítico del llamado "examen vestibular de 10 minutos del paciente mareado"y que permita llegar a conclusiones sobre la sensibilidad y especificidad de este examen abreviado. Material y método: En este estudio, se describen, interpretan y analizan, según la información bibliográfica disponible, particularmente aquellos estudios de la medicina basada en evidencias las siguientes pruebas propuestas en el examen vestibular abreviado: Búsqueda del nistagmus espontáneo, búsqueda del nistagmus de mirada excéntrica, estudio de los movimientos oculares lentos o de rastreo ocular, estudio de los movimientos oculares rápidos o sacadas, test de Halmagyi, test de agitación cefálica, test de agudeza visual dinámica, test de inhibición de la fijación del nistagmus, maniobra de Dix y Hallpike, test de otoscopía neumática, estudio cerebeloso, estudio de la sensibilidad profunda, prueba de Romberg y estudio de la marcha. Debido a que varias de estas pruebas se efectúan en la prueba vestibular clásica sólo se analizan y discuten aquellas que no se efectúan de rutina en este examen. Resultados: Las pruebas analizadas del examen vestibular abreviado revelan en su gran mayoría baja sensibilidad, menor de 50%, pero una buena especificidad. Con algún entrenamiento básico son fáciles de realizar y requieren poco tiempo para su ejecución pero sí, mucho más que 10 minutos. Discusión: Considerando el largo tiempo que requiere el especialista para efectuar un examen vestibular completo, un estudio básico resulta necesario para orientar la investigación clínica de un paciente vertiginoso. Las pruebas propuestas en este examen, tienen baja sensibilidad consideradas individualmente, pero la realización de todas ellas en su conjunto, le confiere al estudio una gran fortaleza y credibilidad, esto necesariamente unido a una muy buena anamnesis con cuestionario estructurado preestablecido. Conclusiones: El examen vestibular abreviado es un buen estudio, en que si bien las diferentes pruebas tienen baja sensibilidad, el resultado de la suma de todas ellas le confiere al examen una buena confiabilidad. Para su realización es indispensable un buen manejo de las pruebas y un buen conocimiento de la otoneurología por parte del examinador para su correcta interpretación. No existen estudios de medicina basada en evidencias de nivel 1 ó 2 que le otorguen alta credibilidad a estas pruebas. Este examen no debe reemplazar al examen vestibular clásico o formal, incluyendo las pruebas calóricas bi-termales, sino que deben ser consideradas como un estudio básico que permite orientar al especialista para tomar decisiones apropiadas diagnósticas y terapéuticas.Introduction: Caloric tests play a very important role in a patient's vestibular exam. But these exams, along with the new test brought about by both technology and computing in Medicine, have turned these examinations into very long and expensive procedures. Taking all this into account, it seems suitable the realization of a preliminary vestibular exam performed in the doctor's consultation office. This will allow a diagnostic guideline with solid foundations. Aim: To describe, interpret, and carry out a critical analysis of the so called "10 minute vestibular examination of the dizzy patient" in order to get to some conclusions about sensitivity and specificity of this short exam. Material and method: Using the availab

Alejandro Peña M

2011-08-01

155

El examen vestibular abreviado, descripción, interpretación y análisis / The abbreviated vestibular exam, description, interpretation and analysis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Introducción: En el examen vestibular de un paciente vertiginoso juegan un rol muy importante las pruebas calóricas, pero la realización de éstas, unida a las nuevas pruebas que ha traído el avance tecnológico y computacional de la medicina, ha significado que el examen vestibular se ha convertido e [...] n la práctica diaria en un estudio muy largo y oneroso, por tal motivo parece útil la realización de un examen vestibular abreviado preliminar hecho en la misma consulta del médico que permita dar una orientación diagnóstica de bases sólidas. Objetivos: El propósito de este estudio es la descripción, interpretación y análisis crítico del llamado "examen vestibular de 10 minutos del paciente mareado"y que permita llegar a conclusiones sobre la sensibilidad y especificidad de este examen abreviado. Material y método: En este estudio, se describen, interpretan y analizan, según la información bibliográfica disponible, particularmente aquellos estudios de la medicina basada en evidencias las siguientes pruebas propuestas en el examen vestibular abreviado: Búsqueda del nistagmus espontáneo, búsqueda del nistagmus de mirada excéntrica, estudio de los movimientos oculares lentos o de rastreo ocular, estudio de los movimientos oculares rápidos o sacadas, test de Halmagyi, test de agitación cefálica, test de agudeza visual dinámica, test de inhibición de la fijación del nistagmus, maniobra de Dix y Hallpike, test de otoscopía neumática, estudio cerebeloso, estudio de la sensibilidad profunda, prueba de Romberg y estudio de la marcha. Debido a que varias de estas pruebas se efectúan en la prueba vestibular clásica sólo se analizan y discuten aquellas que no se efectúan de rutina en este examen. Resultados: Las pruebas analizadas del examen vestibular abreviado revelan en su gran mayoría baja sensibilidad, menor de 50%, pero una buena especificidad. Con algún entrenamiento básico son fáciles de realizar y requieren poco tiempo para su ejecución pero sí, mucho más que 10 minutos. Discusión: Considerando el largo tiempo que requiere el especialista para efectuar un examen vestibular completo, un estudio básico resulta necesario para orientar la investigación clínica de un paciente vertiginoso. Las pruebas propuestas en este examen, tienen baja sensibilidad consideradas individualmente, pero la realización de todas ellas en su conjunto, le confiere al estudio una gran fortaleza y credibilidad, esto necesariamente unido a una muy buena anamnesis con cuestionario estructurado preestablecido. Conclusiones: El examen vestibular abreviado es un buen estudio, en que si bien las diferentes pruebas tienen baja sensibilidad, el resultado de la suma de todas ellas le confiere al examen una buena confiabilidad. Para su realización es indispensable un buen manejo de las pruebas y un buen conocimiento de la otoneurología por parte del examinador para su correcta interpretación. No existen estudios de medicina basada en evidencias de nivel 1 ó 2 que le otorguen alta credibilidad a estas pruebas. Este examen no debe reemplazar al examen vestibular clásico o formal, incluyendo las pruebas calóricas bi-termales, sino que deben ser consideradas como un estudio básico que permite orientar al especialista para tomar decisiones apropiadas diagnósticas y terapéuticas. Abstract in english Introduction: Caloric tests play a very important role in a patient's vestibular exam. But these exams, along with the new test brought about by both technology and computing in Medicine, have turned these examinations into very long and expensive procedures. Taking all this into account, it seems s [...] uitable the realization of a preliminary vestibular exam performed in the doctor's consultation office. This will allow a diagnostic guideline with solid foundations. Aim: To describe, interpret, and carry out a critical analysis of the so called "10 minute vestibular examination of the dizzy patient" in order to get to some conclusions abou

Alejandro, Peña M.

2011-08-01

156

The vestibular contribution to the head direction signal and navigation.  

Science.gov (United States)

Spatial learning and navigation depend on neural representations of location and direction within the environment. These representations, encoded by place cells and head direction (HD) cells, respectively, are dominantly controlled by visual cues, but require input from the vestibular system. Vestibular signals play an important role in forming spatial representations in both visual and non-visual environments, but the details of this vestibular contribution are not fully understood. Here, we review the role of the vestibular system in generating various spatial signals in rodents, focusing primarily on HD cells. We also examine the vestibular system's role in navigation and the possible pathways by which vestibular information is conveyed to higher navigation centers. PMID:24795578

Yoder, Ryan M; Taube, Jeffrey S

2014-01-01

157

Plasticity during Vestibular Compensation: The Role of Saccades  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper is focused on one major aspect of compensation: the recent measures of saccadic responses to high acceleration head turns during human vestibular compensation and their possible implications for recovery after unilateral vestibular loss (UVL). New measurement techniques have provided additional insights into how patients recover after UVL and have given clues for vestibular rehabilitation. Prior to this it has not been possible to quantify the level of function of all the periphera...

Macdougall, Hamish Gavin; Curthoys, Ian S.

2012-01-01

158

Interactions between Stress and Vestibular Compensation - A Review.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Elevated levels of stress and anxiety often accompany vestibular dysfunction, while conversely complaints of dizziness and loss of balance are common in patients with panic and other anxiety disorders. The interactions between stress and vestibular function have been investigated both in animal models and in clinical studies. Evidence from animal studies indicates that vestibular symptoms are effective in activating the stress axis, and that the acute stress response is important in promoting...

2012-01-01

159

Effect of a glutamate blocker, ipenoxazone hydrochloride on the hypoxia-induced firing in the medial vestibular nucleus.  

Science.gov (United States)

To elucidate the effectiveness of the drug in the treatment of vertebrobasilar insufficiency (VBI), we performed an electrophysiological study to examine the effects of ipenoxazone hydrochloride, a glutamate blocker, on hypoxia-induced firing in the medial vestibular nucleus (MVN) neuron, using alpha-chloralose-anesthetized cats. The single neuronal activity of the MVN was recorded extracellularly with a glass-insulated silver wire microelectrode attached along a seven-barrel micropipette. The firing rate of MVN neurons showed a transient increase [hypoxic depolarization (HD)] during 5% O(2) inhalation, followed by a gradual decrease and disappearance. HD and the time to disappearance of firing induced by hypoxia were inhibited by iontophoretic application of ipenoxazone hydrochloride. These results suggest that ipenoxazone hydrochloride protects against hypoxic neuronal dysfunction, and may be an effective drug for vertigo caused by VBI. PMID:15277038

Inoue, Shino; Yamanaka, Toshiaki; Okamoto, Hideyuki; Hosoi, Hiroshi

2004-08-01

160

Experiment M131. Human vestibular function  

Science.gov (United States)

The lower susceptibility to vestibular stimulation aloft, compared with that on ground under experimental conditions, is attributed to a precondition, namely, either there is no need to adapt, or, as exemplified by the Skylab 3 pilot, adaptation to weightlessness is achieved. Findings in some of the astronauts emphasize the distinction between two categories of vestibular side effects: immediate reflex phenomena (illusions, sensations of turning, etc.), and delayed epiphenomena that include the constellation of symptoms and syndromes comprising motion sickness. The drug combinations 1-scopolamine and d-amphetamine and promethazine hydrochloride and ephedrine sulfate are effective in prevention and treatment of motion sickness. It is concluded that prevention of motion sickness in any stressful motion environment involves selection, adaptation, and the use of drugs.

Graybiel, A.; Miller, E. F., II; Homick, J. L.

1977-01-01

 
 
 
 
161

Neural correlates of oddball detection in self-motion heading: a high-density event-related potential study of vestibular integration.  

Science.gov (United States)

The perception of self-motion is a product of the integration of information from both visual and non-visual cues, to which the vestibular system is a central contributor. It is well documented that vestibular dysfunction leads to impaired movement and balance, dizziness and falls, and yet our knowledge of the neuronal processing of vestibular signals remains relatively sparse. In this study, high-density electroencephalographic recordings were deployed to investigate the neural processes associated with vestibular detection of changes in heading. To this end, a self-motion oddball paradigm was designed. Participants were translated linearly 7.8 cm on a motion platform using a one second motion profile, at a 45° angle leftward or rightward of straight ahead. These headings were presented with a stimulus probability of 80-20 %. Participants responded when they detected the infrequent direction change via button-press. Event-related potentials (ERPs) were calculated in response to the standard (80 %) and target (20 %) movement directions. Statistical parametric mapping showed that ERPs to standard and target movements differed significantly from 490 to 950 ms post-stimulus. Topographic analysis showed that this difference had a typical P3 topography. Individual participant bootstrap analysis revealed that 93.3 % of participants exhibited a clear P3 component. These results indicate that a perceived change in vestibular heading can readily elicit a P3 response, wholly similar to that evoked by oddball stimuli presented in other sensory modalities. This vestibular-evoked P3 response may provide a readily and robustly detectable objective measure for the evaluation of vestibular integrity in various disease models. PMID:22434342

Nolan, H; Butler, J S; Whelan, R; Foxe, J J; Bülthoff, H H; Reilly, R B

2012-05-01

162

Nystagmus induced by electrical stimulation of the vestibular and prepositus hypoglossi nuclei in the monkey: evidence for site of induction of velocity storage  

Science.gov (United States)

Electrical stimulation of the vestibular nuclei (VN) and prepositus hypoglossi nuclei (PPH) of alert cynomolgus monkeys evoked nystagmus and eye deviation while they were in darkness. At some sites in VN, nystagmus and after-nystagmus were induced with characteristics suggesting that velocity storage had been excited. We analyzed these responses and compared them to the slow component of optokinetic nystagmus (OKN) and to optokinetic after-nystagmus (OKAN). We then recorded unit activity in VN and determined which types of nystagmus would be evoked from the sites of recording. Nystagmus and eye deviations were also elicited by electrical stimulation of PPH, and we characterized the responses where unit activity was recorded in PPH. Horizontal slow phase velocity of the VN "storage" responses was contralateral to the side of stimulation. The rising time constants and peak steady-state velocities were similar to those of OKN, and the falling time constants of the after-nystagmus and of OKAN were approximately equal. Both the induced after-nystagmus and OKAN were habituated by stimulation of the VN. When horizontal after-nystagmus was evoked with animals on their sides, it developed yaw and pitch components that tended to shift the vector of the slow phase velocity toward the spatial vertical. Similar "cross-coupling" occurs for horizontal OKAN or for vestibular post-rotatory nystagmus elicited in tilted positions. Thus, the storage component of nystagmus induced by VN stimulation had the same characteristics as the slow component of OKN and the VOR. Positive stimulus sites for inducing nystagmus with typical storage components were located in rostral portions of VN. They lay in caudal ventral superior vestibular nucleus (SVN), dorsal portions of central medial vestibular nucleus (MVN) caudal to the abducens nuclei and in adjacent lateral vestibular nucleus (LVN). More complex stimulus responses, but with contralateral after-nystagmus, were induced from surrounding regions of ventral MVN and LVN, rostral descending vestibular nucleus and the marginal zone between MVN and PPH. Vestibular-only (VO), vestibular plus saccade (VPS) and tonic vestibular pause (TVP) units were identified by extracellular recording. Stimulation near type I lateral and vertical canal-related VO units elicited typical "storage" responses with after-nystagmus in 23 of 29 tracks (79%). Stimulus responses were more complex from the region of neurons with oculomotor-related signals, i.e., TVP or VPS cells, although after-nystagmus was also elicited from these sites. Effects of vestibular nerve and nucleus stimulation were compared.(ABSTRACT TRUNCATED AT 400 WORDS).

Yokota, J.; Reisine, H.; Cohen, B.

1992-01-01

163

Achados vestibulares em pacientes portadores de fibromialgia / Vestibular findings in fibromyalgia patients  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese INTRODUÇÃO: A fibromialgia (FM) é uma síndrome musculoesquelética não inflamatória, de caráter crônico, de etiologia desconhecida, caracterizada por dor difusa, aumento da sensibilidade na palpação e por sintomas como fadiga, insônia, ansiedade, depressão, intolerância ao frio e queixas otológicas. [...] OBJETIVO: Avaliar o comportamento vestibular em pacientes portadores de fibromialgia. MÉTODO: Foi realizado um estudo retrospectivo de corte transversal. Avaliaram-se 25 pacientes na faixa etária entre 26 e 65 anos (média de idade - 52,2 anos e desvio padrão - 10,3 anos), submetidos aos seguintes procedimentos: anamnese, avaliação otorrinolaringológica e vestibular por meio da vectoeletronistagmografia. RESULTADOS: a) Os sintomas otoneurológicos mais evidenciados foram: dificuldade ou dor ao movimento do pescoço e dor irradiada para ombro ou braço (92,0%) em cada, tontura (84,0%) e cefaleia (76,0%). Os sintomas clínicos diversos mais relatados foram: depressão (80,0%), ansiedade (76,0%) e insônia (72,0%); b) O exame vestibular esteve alterado em 12 pacientes (48,0%) sendo localizado na prova calórica; c) Houve prevalência de alteração no sistema vestibular periférico e, d) Houve predomínio das disfunções vestibulares periféricas deficitárias. CONCLUSÃO: Este estudo permitiu verificar a importância do exame labiríntico o que ressalta que esse tipo de população deveria ser melhor estudada, uma vez que diversas doenças reumatológicas pelas suas manifestações e áreas de comprometimento podem gerar alterações vestibulares importantes. Abstract in english INTRODUCTION: Fibromyalgia (FM) is a non-inflammatory musculoskeletal chronic syndrome, whose etiology is unknown, characterized by a diffuse pain, increase in palpation sensitivity and such symptoms as tiredness, insomnia, anxiety, depression, cold intolerance and otologic complaints. OBJECTIVE: Ev [...] aluate the vestibular behavior in fibromyalgia patients. METHOD: A retrospective transversal study was performed. 25 patients aged between 26 and 65 (average age - 52. 2 and standard deviation - 10. 3) were evaluated and submitted to the following procedures: anamnesis, otorhinolaryngologic and vestibular evaluation by way of vector electronystamography. RESULTS: a) The most evident otoneurologic symptoms were: difficulty or pain when moving the neck and pain was spread to an arm or shoulder (92. 0%) in each, dizziness (84. 0%) and headache (76. 0%). The different clinical symptoms mostly reported were: depression (80. 0%), anxiety (76. 0%) and insomnia (72. 0%); b) vestibular examination showed an alteration in 12 patients (48. 0%) in the caloric test; c) an alteration in the peripheral vestibular system prevailed, and d) deficient peripheral vestibular disorders were prevalent. CONCLUSION: This study enabled the importance of the labyrinthic test to be verified, thus emphasizing that this kind of people must be studied better, since a range of rheumatologic diseases can cause severe vestibular changes as a result of their manifestations and impairment areas.

Bianca Simone, Zeigelboim; Denise Nunnes, Moreira.

2011-09-01

164

Imaging Finding in 222 Patients with Vestibular  

Directory of Open Access Journals (Sweden)

Full Text Available Background/Objective: Vestibular Schwannoma is the most common cranial schwannoma with gradually produce sensorineural deafness. In this study we observed the effect of Gamma Knife therapy for control of this type of schwannoma."nPatients and Methods: We observed imaging findings of 250 patients with vestibular schwannoma from September 2003 to October 2007. We performed the Gamma Knife with C model (Elekta Company for the treatment and control of the tumor."nResults: The minimum age of our patients was 14 years and maximum age was 90 years. Twenty six patients was N.F.2, and female to male ratio was 2/1. The most common imaging finding was loss of central contrast enhancement in contrast MRI beginning after nine months after Gamma Knife. Loss of volume and cystic changes were other imaging findings and regrowth of tumor was seen in same case. After three years follow up, tumor control, tumor regression, and tumor enlargement were seen in 85%, 10%, and 5% of our patients respectively."nConclusion: Gamma Knife should be considered as a suitable treatment option for the treatment of Vestibular Schwannoma.

A. Zahiri

2008-01-01

165

Electrical vestibular stimulation and space motion sickness  

Science.gov (United States)

Electrical vestibular stimulation (EVS) in dynamic balance condition was studied in order to search for a new provocative test of space motion sickness (SMS). SMS is usually attributed to a sensory conflict caused by exposure to microgravity. Vestibular information is conflicting but also unusual and insignificant. EVS is in accordance with this feature because it is not the adequate stimulus of the vestibular receptors. EVS was achieved by means of binaural electrical stimulation. Effects of EVS were potentiated by compelling the subject to maintain dynamic balance on a seesaw. The quantification of this function was performed before, during and after EVS in order to investigate a possible relationship between objective consequences of EVS i.e. dynamic balance disturbances, and the discomfort experienced by the subjects. Dynamic balancing skill was statistically worsened during EVS. Moreover EVS evoked subjective symptoms of SMS in 17 out of the 30 subjects examined. During EVS in eyes open conditions, the subjects who encountered the strongest discomfort, presented the most disturbed dynamic balance, evidencing a relationship between the level of discomfort and the imbalance arising from EVS. This method could thus constitute an interesting basis of SMS ground-based test.

Severac, Alexandra

166

Fractionated radiation therapy for vestibular schwannoma.  

Science.gov (United States)

Vestibular schwannomas are the most common tumors of the cerebellopontine angle. Multiple management paradigms exist for patients with these benign tumors, including observation, microsurgery, stereotactic radiosurgery, and fractionated radiation therapy, or some combination of these. While the proper course of management is controversial, the goals of therapy are to achieve excellent local tumor control and optimize functional outcomes with as little treatment-related morbidity as possible. Decision-making is tailored to patient-specific factors such as tumor size, clinical presentation, patient age, and goals of hearing preservation. We review the literature in order to summarize the application of fractionated radiation therapy to this tumor entity, where it is used as a primary treatment or, more commonly, as an adjunct therapy. We also provide an overview of the use of fractionated radiation therapy for the preservation of hearing and facial function, and dosing and other technical considerations, in light of the indolent natural history of vestibular schwannomas. We also discuss potential risks associated with this treatment modality, including its effects on temporal bone structures and cranial nerves among other possible complications. Lastly, we outline future directions in this rapidly evolving segment of vestibular schwannoma therapy, which has benefited from the advent of intensity-modulated radiation therapy coupled with stereotactic localization. PMID:24513160

Jian, Brian J; Kaur, Gurvinder; Sayegh, Eli T; Bloch, Orin; Parsa, Andrew T; Barani, Igor J

2014-07-01

167

Reabilitação vestibular: utilidade clínica em pacientes com esclerose múltipla / Vestibular rehabilitation: clinical benefits to patients with multiple sclerosis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo desse estudo foi analisar a eficácia do exercício de reabilitação vestibular em dois casos de esclerose múltipla remitente-recorrente. Ambos os casos foram encaminhados do Hospital de Clínicas para o Laboratório de Otoneurologia de uma instituição de ensino e foram submetidos aos seguinte [...] s procedimentos: anamnese, inspeção otológica, avaliação vestibular e aplicação do Dizziness Handicap Inventory pré e pós reabilitação vestibular utilizando-se o protocolo de Cawthorne e Cooksey. No primeiro caso, gênero feminino, 35 anos, tempo de doença de seis anos, referiu tontura há três anos, de intensidade moderada de ocorrência frequente, cefaléia, quedas, desvio de marcha à direita e sensação de desmaio (sic). Apresentou no exame labiríntico, síndrome vestibular periférica deficitária bilateral. No segundo caso, gênero feminino, 49 anos, tempo de doença de dois anos, referiu desvio de marcha à direita, dificuldade e/ou dor ao movimento do pescoço, formigamento de extremidade e alteração vocal. Apresentou no exame labiríntico, síndrome vestibular periférica deficitária à direita. Houve melhora significativa em ambos os casos dos aspectos físico, funcional e emocional do Dizziness Handicap Inventory após a realização da reabilitação vestibular. O protocolo utilizado promoveu melhora na qualidade de vida e auxiliou no processo de compensação vestibular. Abstract in english The aim of the present study was to analyze the effectiveness of vestibular rehabilitation exercises in two cases of remittent-recurrent multiple sclerosis. Both cases were referred from the Clinics Hospital to the Laboratory of Otoneurology of the same institution and were submitted to the followin [...] g procedures: anamnesis, otological inspection, vestibular evaluation, and application of the Dizziness Handicap Inventory before and after vestibular rehabilitation using the Cawthorne and Cooksey protocol. The first case was a 35-year-old female, diagnosed for six years, who referred frequent dizziness of moderate intensity for three years, headaches, falls, deviation of gait to the right and fainting sensations (sic). In the vestibular exam, she presented bilateral peripheral vestibular deficiency syndrome. The second case was a 49-year-old female, diagnosed for two years, who referred deviation of gait to the right, difficulty and/or pain with neck movement, paraesthesia of the extremities and vocal alteration. In the vestibular exam, she presented peripheral vestibular deficiency syndrome to the right. Both cases had significant improvements regarding physical, functional and emotional aspects of the Dizziness Handicap Inventory after vestibular rehabilitation. The protocol used benefitted the subjects' quality of life and favored the process of vestibular compensation.

Bianca Simone, Zeigelboim; Karlin Fabianne, Klagenberg; Paulo Breno Noronha, Liberalesso.

168

Bead Neuron  

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Using string and beads of different colors, students will make bead neurons and use them as models to understand the specialized cellular structure and function of neurons and how neurons communicate with each other.

Dr. Janet M Dubinsky (University of Minnesota Neuroscience)

2008-11-06

169

Enxaqueca associada a disfunção auditivo-vestibular / Migraine associated with auditory-vestibular dysfunction  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A associação de distúrbios da audição e equilíbrio com enxaqueca é reconhecida desde a Grécia antiga quando Aretaeus da Capadócia em 131 a.C., fez uma descrição precisa e com detalhes desta ocorrência durante uma crise de enxaqueca. Uma revisão ampla das manifestações otoneurológicas da enxaqueca é [...] apresentada, usando as mais recentes publicações com respeito à epidemiologia, apresentação clínica, fisiopatologia, métodos diagnósticos e manejo desta síndrome. OBJETIVO: Descrever a entidade clínica "Enxaqueca associada a Disfunção Auditivo-vestibular" no intuito de ajudar médicos otorrinolaringologistas e neurologistas no diagnóstico e no manejo clínico dessa doença. COMENTÁRIOS FINAIS: Uma forte associação existe entre sintomas otoneurológicos e enxaqueca, sendo a enxaqueca associada a disfunção auditivo-vestibular a causa mais comum de vertigem episódica espontânea (não-posicional). Os sintomas podem variar bastante entre pacientes tornando um desafio diagnóstico para o otorrinolaringologista. Esta entidade geralmente se apresenta com ataques de vertigem espontâneos ou posicionais, durando de segundos a dias com sintomas de enxaqueca associados. Uma melhor elucidação da ligação entre os mecanismos vestibulares centrais e os mecanismos da enxaqueca em si, além da descoberta de defeitos em canais iônicos em algumas causas de enxaqueca, ataxia e vertigem, podem levar a um entendimento maior da fisiopatologia da enxaqueca associada a disfunção auditivo-vestibular. Abstract in english The association between hearing and balance disorders with migraine is known since the times of the ancient Greeks, when Aretaeus from Cappadocia in 131 B.C, made an accurate and detailed description of this occurrence during a migraine episode. We present a broad review of migraine neurotological m [...] anifestations, using the most recent publications associated with epidemiology, clinical presentation, pathophysiology, diagnostic methods and treatment for this syndrome. AIM: to describe the clinical entity: "Migraine associated with auditory-vestibular dysfunction" in order to help otorhinolaryngologists and neurologists in the diagnosis and management of such disorder. FINAL REMARKS: There is a strong association between neurotological symptoms and migraine, and the auditory-vestibular dysfunction-associated migraine is the most common cause of spontaneous episodic vertigo (non-positional). Symptoms may vary broadly among patients, making it a diagnostic challenge to the otorhinolaryngologist. This entity usually presents with positional or spontaneous vertigo spells, lasting for seconds or days, associated with migraine symptoms. A better understanding of the relationship between central vestibular mechanisms and migraine mechanisms, besides the discovery of ionic channel disorders in some cases of migraine, ataxia and vertigo, may lead to a better understanding of migraine pathophysiology associated with audio-vestibular disorder.

Renato, Cal; Fayez, Bahmad Jr.

2008-08-01

170

Queixas auditivas e vestibulares durante a gestação / Hearing and vestibular complaints during pregnancy  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese As disfunções hormonais presentes na mulher durante a gravidez podem causar desordens vestibulares e/ou cocleares. OBJETIVO: Verificar a ocorrência de queixas auditivas e vestibulares em gestantes. MATERIAL E MÉTODO: Este é um estudo prospectivo no qual participaram 82 gestantes. Para pesquisa das q [...] ueixas auditivas e vestibulares foi aplicado às gestantes o Protocolo de Anamnese proposto por Castagno (1994). RESULTADOS: Pode-se observar que o zumbido foi a queixa auditiva mais citada (33%), sem diferença entre os trimestres gestacionais. A queixa de tontura esteve presente em 52,44% das gestantes e principalmente no primeiro trimestre gestacional. Quanto aos sintomas relacionados à tontura, no primeiro trimestre o mais frequente foi a vertigem, já no segundo trimestre gestacional foi a instabilidade e o desequilíbrio ao caminhar e no terceiro trimestre gestacional foi a instabilidade seguida da tendência a cair. A náusea é o principal sintoma associado à tontura nas gestantes, sendo mais frequente no primeiro trimestre gestacional. CONCLUSÃO: Mulheres durante a gestação referem queixas auditivas e vestibulares, principalmente tontura e zumbido. Abstract in english Hormonal dysfunctions in women during pregnancy can cause vestibular and/or cochlear disorders. AIM: to study hearing and vestibular complaints in pregnant women. MATERIAL AND METHOD: this is a prospective study. 82 pregnant women participated on this study. For hearing and vestibular complaints, a [...] questionnaire proposed by Castagno (1994) was employed. RESULTS: we could observe that tinnitus was the main auditory complaint (33%), although with no differences between the groups. Tinnitus was present among 52.44% of the pregnant women, mainly in the Group 2. According to symptoms related to dizziness, vertigo was the main auditory complaint in first trimester, whereas instability and gait unbalance were more frequent in the second trimester, and instability and tendency to fall in the third trimester. Nausea was the main symptom associated with dizziness in pregnant women, being more frequent in the first trimester of gestation. CONCLUSIONS: women during gestation have auditory and vestibular complaints, mainly dizziness and tinnitus.

Paula Michele da Silva, Schmidt; Franciele da Trindade, Flores; Angela Garcia, Rossi; Aron Ferreira da, Silveira.

2010-02-01

171

Queixas auditivas e vestibulares durante a gestação / Hearing and vestibular complaints during pregnancy  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese As disfunções hormonais presentes na mulher durante a gravidez podem causar desordens vestibulares e/ou cocleares. OBJETIVO: Verificar a ocorrência de queixas auditivas e vestibulares em gestantes. MATERIAL E MÉTODO: Este é um estudo prospectivo no qual participaram 82 gestantes. Para pesquisa das q [...] ueixas auditivas e vestibulares foi aplicado às gestantes o Protocolo de Anamnese proposto por Castagno (1994). RESULTADOS: Pode-se observar que o zumbido foi a queixa auditiva mais citada (33%), sem diferença entre os trimestres gestacionais. A queixa de tontura esteve presente em 52,44% das gestantes e principalmente no primeiro trimestre gestacional. Quanto aos sintomas relacionados à tontura, no primeiro trimestre o mais frequente foi a vertigem, já no segundo trimestre gestacional foi a instabilidade e o desequilíbrio ao caminhar e no terceiro trimestre gestacional foi a instabilidade seguida da tendência a cair. A náusea é o principal sintoma associado à tontura nas gestantes, sendo mais frequente no primeiro trimestre gestacional. CONCLUSÃO: Mulheres durante a gestação referem queixas auditivas e vestibulares, principalmente tontura e zumbido. Abstract in english Hormonal dysfunctions in women during pregnancy can cause vestibular and/or cochlear disorders. AIM: to study hearing and vestibular complaints in pregnant women. MATERIAL AND METHOD: this is a prospective study. 82 pregnant women participated on this study. For hearing and vestibular complaints, a [...] questionnaire proposed by Castagno (1994) was employed. RESULTS: we could observe that tinnitus was the main auditory complaint (33%), although with no differences between the groups. Tinnitus was present among 52.44% of the pregnant women, mainly in the Group 2. According to symptoms related to dizziness, vertigo was the main auditory complaint in first trimester, whereas instability and gait unbalance were more frequent in the second trimester, and instability and tendency to fall in the third trimester. Nausea was the main symptom associated with dizziness in pregnant women, being more frequent in the first trimester of gestation. CONCLUSIONS: women during gestation have auditory and vestibular complaints, mainly dizziness and tinnitus.

Paula Michele da Silva, Schmidt; Franciele da Trindade, Flores; Angela Garcia, Rossi; Aron Ferreira da, Silveira.

172

Balancing the mind: vestibular induced facilitation of egocentric mental transformations.  

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The body schema is a key component in accomplishing egocentric mental transformations, which rely on bodily reference frames. These reference frames are based on a plurality of different cognitive and sensory cues among which the vestibular system plays a prominent role. We investigated whether a bottom-up influence of vestibular stimulation modulates the ability to perform egocentric mental transformations. Participants were significantly faster to make correct spatial judgments during vestibular stimulation as compared to sham stimulation. Interestingly, no such effects were found for mental transformation of hand stimuli or during mental transformations of letters, thus showing a selective influence of vestibular stimulation on the rotation of whole-body reference frames. Furthermore, we found an interaction with the angle of rotation and vestibular stimulation demonstrating an increase in facilitation during mental body rotations in a direction congruent with rightward vestibular afferents. We propose that facilitation reflects a convergence in shared brain areas that process bottom-up vestibular signals and top-down imagined whole-body rotations, including the precuneus and tempero-parietal junction. Ultimately, our results show that vestibular information can influence higher-order cognitive processes, such as the body schema and mental imagery. PMID:22750744

Falconer, Caroline J; Mast, Fred W

2012-01-01

173

Facial myokymia as a presenting symptom of vestibular schwannoma.  

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Full Text Available Facial myokymia is a rare presenting feature of a vestibular schwannoma. We present a 48 year old woman with a large right vestibular schwannoma, who presented with facial myokymia. It is postulated that facial myokymia might be due to a defect in the motor axons of the 7th nerve or due to brain stem compression by the tumor.

Joseph B

2002-07-01

174

Evidence for cognitive vestibular integration impairment in idiopathic scoliosis patients  

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Full Text Available Abstract Background Adolescent idiopathic scoliosis is characterized by a three-dimensional deviation of the vertebral column and its etiopathogenesis is unknown. Various factors cause idiopathic scoliosis, and among these a prominent role has been attributed to the vestibular system. While the deficits in sensorimotor transformations have been documented in idiopathic scoliosis patients, little attention has been devoted to their capacity to integrate vestibular information for cognitive processing for space perception. Seated idiopathic scoliosis patients and control subjects experienced rotations of different directions and amplitudes in the dark and produced saccades that would reproduce their perceived spatial characteristics of the rotations (vestibular condition. We also controlled for possible alteration of the oculomotor and vestibular systems by measuring the subject's accuracy in producing saccades towards memorized peripheral targets in absence of body rotation and the gain of their vestibulo-ocular reflex. Results Compared to healthy controls, the idiopathic scoliosis patients underestimated the amplitude of their rotations. Moreover, the results revealed that idiopathic scoliosis patients produced accurate saccades to memorized peripheral targets in absence of body rotation and that their vestibulo-ocular reflex gain did not differ from that of control participants. Conclusion Overall, results of the present study demonstrate that idiopathic scoliosis patients have an alteration in cognitive integration of vestibular signals. It is possible that severe spine deformity developed partly due to impaired vestibular information travelling from the cerebellum to the vestibular cortical network or alteration in the cortical mechanisms processing the vestibular signals.

Mercier Pierre

2009-08-01

175

Effect of meprobamate on the vestibulosensory and vestibular somatic reaction  

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The influence of meprobamate on the vestibular illusion of counter-rotation, movement coordination and vertical writing was investigated by a double blind trial method and placebo. The results confirm the possibility of the meprobamate application for prophylaxis and correction of vestibular disturbances.

Khinchikashvili, N. V.

1980-01-01

176

Vestibular and visual responses in human posterior insular cortex.  

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The central hub of the cortical vestibular network in humans is likely localized in the region of posterior lateral sulcus. An area characterized by responsiveness to visual motion has previously been described at a similar location and named posterior insular cortex (PIC). Currently it is not known whether PIC processes vestibular information as well. We localized PIC using visual motion stimulation in functional magnetic resonance imaging (fMRI) and investigated whether PIC also responds to vestibular stimuli. To this end, we designed an MRI-compatible caloric stimulation device that allowed us to stimulate bithermally with hot temperature in one ear and simultaneously cold temperature in the other or with warm temperatures in both ears for baseline. During each trial, participants indicated the presence or absence of self-motion sensations. We found activation in PIC during periods of self motion when vestibular stimulation was carried out with minimal visual input. In combined visual-vestibular stimulation area PIC was activated in a similar fashion during congruent and incongruent stimulation conditions. Our results show that PIC not only responds to visual motion but also to vestibular stimuli related to the sensation of self motion. We suggest that PIC is part of the cortical vestibular network and plays a role in the integration of visual and vestibular stimuli for the perception of self motion. PMID:25185806

Frank, Sebastian M; Baumann, Oliver; Mattingley, Jason B; Greenlee, Mark W

2014-11-15

177

Vestibular schwannoma with contralateral facial pain – case report  

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Full Text Available Abstract Background Vestibular schwannoma (acoustic neuroma most commonly presents with ipsilateral disturbances of acoustic, vestibular, trigeminal and facial nerves. Presentation of vestibular schwannoma with contralateral facial pain is quite uncommon. Case presentation Among 156 cases of operated vestibular schwannoma, we found one case with unusual presentation of contralateral hemifacial pain. Conclusion The presentation of contralateral facial pain in the vestibular schwannoma is rare. It seems that displacement and distortion of the brainstem and compression of the contralateral trigeminal nerve in Meckel's cave by the large mass lesion may lead to this atypical presentation. The best practice in these patients is removal of the tumour, although persistent contralateral pain after operation has been reported.

Ghodsi Mohammad

2003-03-01

178

The role of the vestibular system in manual target localization  

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Astronauts experience perceptual and sensory-motor disturbances during spaceflight and immediately after return to the 1-g environment of Earth. During spaceflight, sensory information from the eyes, limbs and vestibular organs is reinterpreted by the central nervous system so that astronauts can produce appropriate body movements in microgravity. Alterations in sensory-motor function may affect eye-head-hand coordination and, thus, the crewmember's ability to manually locate objects in extrapersonal space. Previous reports have demonstrated that crewmembers have difficulty in estimating joint and limb position and in pointing to memorized target positions on orbit and immediately postflight. One set of internal cues that may assist in the manual localization of objects is information from the vestibular system. This system contributes to our sense of the body's position in space by providing information on head position and movement and the orientation of the body with respect to gravity. Research on the vestibular system has concentrated on its role in oculo-motor control. Little is known about the role that vestibular information plays in manual motor control, such as reaching and pointing movements. Since central interpretation of vestibular information is altered in microgravity, it is important to determine its role in this process. This summer, we determined the importance of vestibular information in a subject's ability to point accurately toward a target in extrapersonal space. Subjects were passively rotated across the earth-vertical axis and then asked to point back to a previously-seen target. In the first paradigm, the subjects used both visual and vestibular cues for the pointing response, while, in the second paradigm, subjects used only vestibular information. Subjects were able to point with 85 percent accuracy to a target using vestibular information alone. We infer from this result that vestibular input plays a role in the spatial programming of manual responses.

Barry, Susan R.; Mueller, S. Alyssa

1995-01-01

179

Paroxismia vestibular: estudo clínico e tratamento de oito pacientes Vestibular paroxysmia: clinical study and treatment of eight patients  

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Full Text Available A paroxismia vestibular é uma síndrome de compressão do VIII nervo craniano e foi denominada inicialmente por Janetta "vertigem posicional incapacitante". Esta síndrome é caracterizada por episódios curtos de vertigem, zumbido, déficit vestibular e auditivo. A RM pode mostrar compressão do VIII nervo por vasos da fossa posterior, como a artéria basilar, artéria vertebral, artéria cerebelar inferior anterior, artéria cerebelar inferior posterior. A paroxismia vestibular pode ser tratada com terapia medicamentosa tais como carbamazepina, fenitoína ou gabapentina, ou com descompressão microvascular do VIII nervo. Este estudo descreve oito pacientes com paroxismia vestibular. Quatro deles mostraram também sinais clínicos sugerindo compressão do V e/ou VII nervos. Sete pacientes tratados com carbamazepina tiveram melhora significativa da vertigem e zumbido.Vestibular paroxysmia is a syndrome of cross-compression of the VIII cranial nerve and was first described by Jannetta who used the term "disabling positional vertigo". This syndrome is characterized by brief attacks of vertigo, tinnitus, vestibular and auditory deficits. MRI may show the VIII nerve compression from vessels in the posterior fossa, such as the basilar, vertebral, anterior-inferior cerebellar or the posterior-inferior cerebellar arteries. Vestibular paroxysmia may be treated either with medical therapy, such as carbamazepine, phenytoin or gabapentin or with the microvascular decompression of the VIII nerve. This study describes eight patients with vestibular paroxysmia. Four of them showed also clinical signs suggesting cross-compression of the V and/or VII nerve. Seven patients treated with carbamazepine had significant improvement of vertigo and tinnitus.

Aline Mizuta Kozoroski Kanashiro

2005-09-01

180

Vestibular prosthesis tested in rhesus monkeys.  

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We are studying the effectiveness of a semicircular canal prosthesis to improve postural control, perception of spatial orientation, and the VOR in rhesus monkeys with bilateral vestibular hypofunction. Balance is examined by measuring spontaneous sway of the body during quiet stance and postural responses evoked by head turns and rotation of the support surface; perception is measured with a task derived from the subjective visual vertical (SVV) test during static and dynamic rotation in the roll plane; and the angular VOR is measured during rotation about the roll, pitch, and yaw axes. After the normal responses are characterized, bilateral vestibular loss is induced with intratympanic gentamicin, and then multisite stimulating electrodes are chronically implanted into the ampullae of all three canals in one ear. The postural, perceptual, and VOR responses are then characterized in the ablated state, and then bilateral, chronic electrical stimulation is applied to the ampullary nerves using a prosthesis that senses angular head velocity in three-dimensions and uses this information to modulate the rate of current pulses provided by the implanted electrodes. We are currently characterizing two normal monkeys with these paradigms, and vestibular ablation and electrode implantation are planned for the near future. In one prior rhesus monkey tested with this approach, we found that a one-dimensional (posterior canal) prosthesis improved balance during head turns, perceived head orientation during roll tilts, and the VOR in the plane of the instrumented canal. We therefore predict that the more complete information provided by a three-dimensional prosthesis that modulates activity in bilaterally-paired canals will exceed the benefits provided by the one-dimensional, unilateral approach used in our preliminary studies. PMID:22254795

Lewis, Richard F; Haburcakova, Csilla; Gong, Wangsong; Lee, Daniel; Wall, Conrad; Thompson, Lara; Merfeld, Daniel M

2011-01-01

 
 
 
 
181

Vestibular control of the head: possible functions of the vestibulocollic reflex  

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Here, we review the angular vestibulocollic reflex (VCR) focusing on its function during unexpected and voluntary head movements. Theoretically, the VCR could (1) stabilize the head in space during body movements and/or (2) dampen head oscillations that could occur as a result of the head’s underdamped mechanics. The reflex appears unaffected when the simplest, trisynaptic VCR pathways are severed. The VCR’s efficacy varies across species; in humans and monkeys, head stabilization is ineffective during low-frequency body movements in the yaw plan. While the appearance of head oscillations after the attenuation of semicircular canal function suggests a role in damping, this interpretation is complicated by defects in the vestibular input to other descending motor pathways such as gaze premotor circuits. Since the VCR should oppose head movements, it has been proposed that the reflex is suppressed during voluntary head motion. Consistent with this idea, vestibular-only (VO) neurons, which are possible vestibulocollic neurons, respond vigorously to passive, but not active, head rotations. Although VO neurons project to the spinal cord, their contribution to the VCR remains to be established. VCR cancelation during active head movements could be accomplished by an efference copy signal negating afferent activity related to active motion. Oscillations occurring during active motion could be eliminated by some combination of reflex actions and voluntary motor commands that take into account the head’s biomechanics. A direct demonstration of the status of the VCR during active head movements is required to clarify the function of the reflex. PMID:21442224

Cullen, Kathleen E.

2013-01-01

182

Adaptive plasticity in vestibular influences on cardiovascular control  

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Data collected in both human subjects and animal models indicate that the vestibular system influences the control of blood pressure. In animals, peripheral vestibular lesions diminish the capacity to rapidly and accurately make cardiovascular adjustments to changes in posture. Thus, one role of vestibulo-cardiovascular influences is to elicit changes in blood distribution in the body so that stable blood pressure is maintained during movement. However, deficits in correcting blood pressure following vestibular lesions diminish over time, and are less severe when non-labyrinthine sensory cues regarding body position in space are provided. These observations show that pathways that mediate vestibulo-sympathetic reflexes can be subject to plastic changes. This review considers the adaptive plasticity in cardiovascular responses elicited by the central vestibular system. Recent data indicate that the posterior cerebellar vermis may play an important role in adaptation of these responses, such that ablation of the posterior vermis impairs recovery of orthostatic tolerance following subsequent vestibular lesions. Furthermore, recent experiments suggest that non-labyrinthine inputs to the central vestibular system may be important in controlling blood pressure during movement, particularly following vestibular dysfunction. A number of sensory inputs appear to be integrated to produce cardiovascular adjustments during changes in posture. Although loss of any one of these inputs does not induce lability in blood pressure, it is likely that maximal blood pressure stability is achieved by the integration of a variety of sensory cues signaling body position in space.

Yates, B. J.; Holmes, M. J.; Jian, B. J.

2000-01-01

183

Vestibular inputs to human motion-sensitive visual cortex.  

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Two crucial sources of information available to an organism when moving through an environment are visual and vestibular stimuli. Macaque cortical area MSTd processes visual motion, including cues to self-motion arising from optic flow and also receives information about self-motion from the vestibular system. In humans, whether human MST (hMST) receives vestibular afferents is unknown. We have combined 2 techniques, galvanic vestibular stimulation and functional MRI (fMRI), to show that hMST is strongly activated by vestibular stimulation in darkness, whereas adjacent area MT is unaffected. The activity cannot be explained in terms of somatosensory stimulation at the electrode site. Vestibular input appears to be confined to the anterior portion of hMST, suggesting that hMST as conventionally defined may contain 2 subregions. Vestibular activity was also seen in another area previously implicated in processing visual cues to self-motion, namely the cingulate sulcus visual area (CSv), but not in visual area V6. The results suggest that cross-modal convergence of cues to self-motion occurs in both hMST and CSv. PMID:21743097

Smith, Andrew T; Wall, Matthew B; Thilo, Kai V

2012-05-01

184

Vestibular rehabilitation therapy: review of indications, mechanisms, and key exercises.  

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Vestibular rehabilitation therapy (VRT) is an exercise-based treatment program designed to promote vestibular adaptation and substitution. The goals of VRT are 1) to enhance gaze stability, 2) to enhance postural stability, 3) to improve vertigo, and 4) to improve activities of daily living. VRT facilitates vestibular recovery mechanisms: vestibular adaptation, substitution by the other eye-movement systems, substitution by vision, somatosensory cues, other postural strategies, and habituation. The key exercises for VRT are head-eye movements with various body postures and activities, and maintaining balance with a reduced support base with various orientations of the head and trunk, while performing various upper-extremity tasks, repeating the movements provoking vertigo, and exposing patients gradually to various sensory and motor environments. VRT is indicated for any stable but poorly compensated vestibular lesion, regardless of the patient's age, the cause, and symptom duration and intensity. Vestibular suppressants, visual and somatosensory deprivation, immobilization, old age, concurrent central lesions, and long recovery from symptoms, but there is no difference in the final outcome. As long as exercises are performed several times every day, even brief periods of exercise are sufficient to facilitate vestibular recovery. Here the authors review the mechanisms and the key exercises for each of the VRT goals. PMID:22259614

Han, Byung In; Song, Hyun Seok; Kim, Ji Soo

2011-12-01

185

Rizatriptan reduces vestibular-induced motion sickness in migraineurs.  

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A previous pilot study suggested that rizatriptan reduces motion sickness induced by complex vestibular stimulation. In this double-blind, randomized, placebo-controlled study we measured motion sickness in response to a complex vestibular stimulus following pretreatment with either rizatriptan or a placebo. Subjects included 25 migraineurs with or without migraine-related dizziness (23 females) aged 21-45 years (31.0 ± 7.8 years). Motion sickness was induced by off-vertical axis rotation in darkness, which stimulates both the semicircular canals and otolith organs of the vestibular apparatus. Results indicated that of the 15 subjects who experienced vestibular-induced motion sickness when pretreated with placebo, 13 showed a decrease in motion sickness following pretreatment with rizatriptan as compared to pretreatment with placebo (P < 0.02). This significant effect was not seen when subjects were exposed to more provocative vestibular stimulation. We conclude that the serotonin agonist, rizatriptan, reduces vestibular-induced motion sickness by influencing serotonergic vestibular-autonomic projections. PMID:20862509

Furman, Joseph M; Marcus, Dawn A; Balaban, Carey D

2011-02-01

186

Pharmacotherapy of vestibular and ocular motor disorders, including nystagmus.  

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We review current pharmacological treatments for peripheral and central vestibular disorders, and ocular motor disorders that impair vision, especially pathological nystagmus. The prerequisites for successful pharmacotherapy of vertigo, dizziness, and abnormal eye movements are the "4 D's": correct diagnosis, correct drug, appropriate dosage, and sufficient duration. There are seven groups of drugs (the "7 A's") that can be used: antiemetics; anti-inflammatory, anti-Ménière's, and anti-migrainous medications; anti-depressants, anti-convulsants, and aminopyridines. A recovery from acute vestibular neuritis can be promoted by treatment with oral corticosteroids. Betahistine may reduce the frequency of attacks of Ménière's disease. The aminopyridines constitute a novel treatment approach for downbeat and upbeat nystagmus, as well as episodic ataxia type 2 (EA 2); these drugs may restore normal "pacemaker" activity to the Purkinje cells that govern vestibular and cerebellar nuclei. A limited number of trials indicate that baclofen improves periodic alternating nystagmus, and that gabapentin and memantine improve acquired pendular and infantile (congenital) nystagmus. Preliminary reports suggest suppression of square-wave saccadic intrusions by memantine, and ocular flutter by beta-blockers. Thus, although progress has been made in the treatment of vestibular neuritis, some forms of pathological nystagmus, and EA 2, controlled, masked trials are still needed to evaluate treatments for many vestibular and ocular motor disorders, including betahistine for Ménière's disease, oxcarbazepine for vestibular paroxysmia, or metoprolol for vestibular migraine. PMID:21461686

Strupp, Michael; Thurtell, Matthew J; Shaikh, Aasef G; Brandt, Thomas; Zee, David S; Leigh, R John

2011-07-01

187

Avaliação vestibular no tremor essencial / Vestibular evaluation in the essential tremor  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese TEMA: o tremor essencial é familial em cerca de 50% dos casos, com uma herança autossômica, possui início insidioso e é lentamente progressivo. PROCEDIMENTOS: avaliou-se no Setor de Otoneurologia de um Hospital Particular em fevereiro de 2007, uma paciente do sexo feminino, branca, 59 anos, casada, [...] artista plástica, com história de tremor na cabeça desde os dois anos de idade (sic). A paciente relata queixa de tontura há vários meses de origem súbita sem acompanhamento de náusea e/ou queda. Nega perda de força muscular e formigamento em membros superiores e inferiores, rebaixamento da acuidade auditiva e zumbido. A paciente relata que um de seus filhos possuiu tremor nas mãos há dois anos e avós maternos e paternos com Parkinson. Realizaram-se os seguintes procedimentos: anamnese, inspeção otológica e avaliação vestibular por meio da vectoeletronistagmografia. RESULTADOS: observaram-se os seguintes achados ao exame vestibular: nistagmo de posicionamento com características centrais, nistagmo espontâneo presente com os olhos abertos, nistagmo semi-espontâneo do tipo múltiplo e hiper-reflexia em valor absoluto à prova calórica 20ºC (OD e OE). CONCLUSÃO: o exame vestibular mostrou-se sensível e importante para captar alterações em provas que sugerissem envolvimento do sistema nervoso central. Abstract in english BACKGROUND: essential tremors are family-related in about 50% of the cases with an autosomal inheritance and they register an insidious beginning with a slow progression. PROCEDURE: a 59 year old, white female patient, married and whose occupation is a plastic artist with a history of head tremors s [...] ince she was two years (sic) old was evaluated in the Otoneurology sector of a private hospital, during the period from February 2007. The patient had been complaining of dizziness from unknown origin for several months without accompanying nausea and/or falls. She denied any loss of muscular strength or tingling in her upper and lower members and neither any lowering of her auditory sharpness nor buzzing. The patient informed that one of her children suffered hand tremors two years ago and also that both grandparents had Parkinson’s disease. The following procedures were performed: anamnesis, otological inspection and vestibular evaluation through vectoelectronystagmography. RESULTS: the following findings from the vestibular exam were observed: positioning nystagmus with central characteristics, spontaneous nystagmus with the eyes open, semi-spontaneous nystagmus of the multiple and hyperreflexia type in readings absolute to the caloric test at 20ºC (RE and LE). CONCLUSION: the vestibular exam was shown to be sensitive and important for garnering alterations in tests that suggested involvement of the central nervous system.

Bianca Simone, Zeigelboim; Cláudia, Mittelmann.

188

Função vestibular no acidente vascular cerebral do território carotídeo / Vestibular function in carotid territory stroke patients  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Pacientes após Acidente Vascular Cerebral (AVC) podem apresentar sintomas otoneurológicos. OBJETIVO: Avaliar a função vestibular de pacientes com antecedente pessoal de AVC no território carotídeo. Desenho científico: estudo de coorte histórica com corte transversal. MÉTODO: Quarenta pacientes foram [...] submetidos à anamnese, exame otorrinolaringológico, Dizziness Handicap Inventory e vectoeletronistagmografia. RESULTADOS: Anormalidades discretas dos movimentos sacádicos foram encontradas em 20 pacientes (50,0%); nove referiram desequilíbrio e um tontura. O ganho do rastreio pendular foi anormal em 17 casos (42,5%); seis referiram desequilíbrio e um tontura. Preponderância direcional anormal do nistagmoperrotatório ocorreu em dois casos (5,0%), que referiram desequilíbrio. A prova calórica identificou três casos (7,5%) com predomínio labiríntico anormal e dois (5,0%) com preponderância direcional anormal do nistagmo; os cinco casos relataram desequilíbrio. Dos 11 pacientes que não referiram manifestações de alteração do equilíbrio corporal, 10 apresentaram alterações nos movimentos sacádicos e no rastreio pendular e um apresentou exame vestibular normal. CONCLUSÃO: Pacientes com antecedente pessoal de AVC no território carotídeo podem apresentar tontura ou desequilíbrio corporal e sinais de comprometimento da motilidade ocular e da função vestibular. Abstract in english Stroke patients may present otoneurological symptoms. OBJECTIVE: To assess the vestibular function of subjects with a history of carotid territory stroke. METHOD: This historical cohort cross sectional study enrolled 40 patients; subjects answered the Dizziness Handicap Inventory, were interviewed a [...] nd submitted to ENT examination and vectorelectronystagmography. RESULTS: Mild saccadic movement anomalies were seen in 20 patients (50.0%); nine complained of imbalance and dizziness. Abnormal smooth pursuit gain was seen in 17 cases (42.5%); six subjects reported imbalance and one complained of dizziness. Abnormal directional preponderance during rotational nystagmus was seen in two cases (5.0%), who also reported imbalance. Three patients (7.5%) and two subjects (5.0%) were found to have abnormal labyrinthine predominance and abnormal nystagmus directional preponderance respectively; all five individuals reported imbalance. Ten of the 11 patients without complaints of disordered balance had altered saccadic and smooth pursuit eye movements, while one had unaltered vestibular function. CONCLUSION: Patients with a history of carotid territory stroke may suffer from dizziness or imbalance and present signs of compromised eye motility and vestibular function.

Anna Paula Batista de Ávila, Pires; Marcia Maiumi, Fukujima; Fernando Freitas, Ganança; Letícia de Moraes, Aquino; Maurício Malavasi, Ganança; Heloisa Helena, Caovilla.

189

Avaliação vestibular no tremor essencial Vestibular evaluation in the essential tremor  

Directory of Open Access Journals (Sweden)

Full Text Available TEMA: o tremor essencial é familial em cerca de 50% dos casos, com uma herança autossômica, possui início insidioso e é lentamente progressivo. PROCEDIMENTOS: avaliou-se no Setor de Otoneurologia de um Hospital Particular em fevereiro de 2007, uma paciente do sexo feminino, branca, 59 anos, casada, artista plástica, com história de tremor na cabeça desde os dois anos de idade (sic. A paciente relata queixa de tontura há vários meses de origem súbita sem acompanhamento de náusea e/ou queda. Nega perda de força muscular e formigamento em membros superiores e inferiores, rebaixamento da acuidade auditiva e zumbido. A paciente relata que um de seus filhos possuiu tremor nas mãos há dois anos e avós maternos e paternos com Parkinson. Realizaram-se os seguintes procedimentos: anamnese, inspeção otológica e avaliação vestibular por meio da vectoeletronistagmografia. RESULTADOS: observaram-se os seguintes achados ao exame vestibular: nistagmo de posicionamento com características centrais, nistagmo espontâneo presente com os olhos abertos, nistagmo semi-espontâneo do tipo múltiplo e hiper-reflexia em valor absoluto à prova calórica 20ºC (OD e OE. CONCLUSÃO: o exame vestibular mostrou-se sensível e importante para captar alterações em provas que sugerissem envolvimento do sistema nervoso central.BACKGROUND: essential tremors are family-related in about 50% of the cases with an autosomal inheritance and they register an insidious beginning with a slow progression. PROCEDURE: a 59 year old, white female patient, married and whose occupation is a plastic artist with a history of head tremors since she was two years (sic old was evaluated in the Otoneurology sector of a private hospital, during the period from February 2007. The patient had been complaining of dizziness from unknown origin for several months without accompanying nausea and/or falls. She denied any loss of muscular strength or tingling in her upper and lower members and neither any lowering of her auditory sharpness nor buzzing. The patient informed that one of her children suffered hand tremors two years ago and also that both grandparents had Parkinson’s disease. The following procedures were performed: anamnesis, otological inspection and vestibular evaluation through vectoelectronystagmography. RESULTS: the following findings from the vestibular exam were observed: positioning nystagmus with central characteristics, spontaneous nystagmus with the eyes open, semi-spontaneous nystagmus of the multiple and hyperreflexia type in readings absolute to the caloric test at 20ºC (RE and LE. CONCLUSION: the vestibular exam was shown to be sensitive and important for garnering alterations in tests that suggested involvement of the central nervous system.

Bianca Simone Zeigelboim

2008-01-01

190

Função vestibular no acidente vascular cerebral do território carotídeo / Vestibular function in carotid territory stroke patients  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Pacientes após Acidente Vascular Cerebral (AVC) podem apresentar sintomas otoneurológicos. OBJETIVO: Avaliar a função vestibular de pacientes com antecedente pessoal de AVC no território carotídeo. Desenho científico: estudo de coorte histórica com corte transversal. MÉTODO: Quarenta pacientes foram [...] submetidos à anamnese, exame otorrinolaringológico, Dizziness Handicap Inventory e vectoeletronistagmografia. RESULTADOS: Anormalidades discretas dos movimentos sacádicos foram encontradas em 20 pacientes (50,0%); nove referiram desequilíbrio e um tontura. O ganho do rastreio pendular foi anormal em 17 casos (42,5%); seis referiram desequilíbrio e um tontura. Preponderância direcional anormal do nistagmoperrotatório ocorreu em dois casos (5,0%), que referiram desequilíbrio. A prova calórica identificou três casos (7,5%) com predomínio labiríntico anormal e dois (5,0%) com preponderância direcional anormal do nistagmo; os cinco casos relataram desequilíbrio. Dos 11 pacientes que não referiram manifestações de alteração do equilíbrio corporal, 10 apresentaram alterações nos movimentos sacádicos e no rastreio pendular e um apresentou exame vestibular normal. CONCLUSÃO: Pacientes com antecedente pessoal de AVC no território carotídeo podem apresentar tontura ou desequilíbrio corporal e sinais de comprometimento da motilidade ocular e da função vestibular. Abstract in english Stroke patients may present otoneurological symptoms. OBJECTIVE: To assess the vestibular function of subjects with a history of carotid territory stroke. METHOD: This historical cohort cross sectional study enrolled 40 patients; subjects answered the Dizziness Handicap Inventory, were interviewed a [...] nd submitted to ENT examination and vectorelectronystagmography. RESULTS: Mild saccadic movement anomalies were seen in 20 patients (50.0%); nine complained of imbalance and dizziness. Abnormal smooth pursuit gain was seen in 17 cases (42.5%); six subjects reported imbalance and one complained of dizziness. Abnormal directional preponderance during rotational nystagmus was seen in two cases (5.0%), who also reported imbalance. Three patients (7.5%) and two subjects (5.0%) were found to have abnormal labyrinthine predominance and abnormal nystagmus directional preponderance respectively; all five individuals reported imbalance. Ten of the 11 patients without complaints of disordered balance had altered saccadic and smooth pursuit eye movements, while one had unaltered vestibular function. CONCLUSION: Patients with a history of carotid territory stroke may suffer from dizziness or imbalance and present signs of compromised eye motility and vestibular function.

Anna Paula Batista de Ávila, Pires; Marcia Maiumi, Fukujima; Fernando Freitas, Ganança; Letícia de Moraes, Aquino; Maurício Malavasi, Ganança; Heloisa Helena, Caovilla.

2013-02-01

191

Ocular vestibular evoked myogenic potentials in normal-hearing adults  

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Background and Aim: Ocular vestibular-evoked myogenic potential (oVEMP) is a novel vestibular function test. This short-latency response can be recorded through contracting extraocular muscles by high-intensity acoustic stimulation and can be used to evaluate contralateral ocular-vestibular reflex. The aim of this study was to record and compare the amplitude, latency, asymmetry ratio and occurrence percentage of oVEMP (n10) and cervical VEMP (p13) responses in a group of normal adult subject...

Mohammad Kamali; Homa Zarinkoub; Akram Pourbakht; Abdoreza Sheibanizade; Maryam Ramezani; Seyede Nazanin Hajari

2012-01-01

192

Vagal and Vestibular Ganglia as Vital Neural-Centers During Development  

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Full Text Available This investigation is an attempt to provide a chronological account of the ontogeny and significance of changing pattern of the neuronal elements in the vagal (nodose and vestibular ganglia of the chick. Two types of morphologically different neuron-types (dark and light ones are observed. The dark cells are considered to be active ones, while the light-cells are effete cells, i.e., inactive, dying, dead or degenerating ones which have failed to establish or lost their functional connections. Since the small and medium sized cells are the youngest stages in which the light cells make their first appearance, it is assumed that the establishment of functional connections might begin around the very-small and small cell stage during embryonic development. The appearance of light cells among the very-small ones just on the day of hatching possibly signifies their attempt to eliminate the growing cells since they are no longer needed to replace larger categories of cells which have already well-developed neuronal connections by the day of hatching. In the vagal ganglion is the occurrence of large number of light-cells on E6 from this behavior, it is assumed that the vagus nerve establishes the earliest functional connections (around E6 or even earlier in view of its vital functions involved in maintaining the life of animal during development because of its connections with vital organs concerned with alimentary, respiratory and cardiac functions. In the vestibular ganglion, the appearance of a few light cells on E6 might indicate the beginning of an early establishment of functional connections in contrast to most other ganglia studied. It is possible that proper maintenance of vestibular function in order to keep the different organs (such as heart, lung, liver, intestine, brain etc in their most suitable position during early stages of development in relation to the gravitational force, is possibly an important factor for proper development and growth of every organ and system of the body, and to the life of the individual at large.

A. G. Pillay

2001-01-01

193

Frequência de alteração vestibular em bombeiros militares de Alagoas / Frequency of vestibular disorder in military firefighters from Alagoas  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVOS: investigar a frequência de alterações vestibulares em bombeiros de Alagoas e suas queixas. MÉTODOS: realizaram-se anamnese e avaliação audiológica, desclassificando da amostra os sujeitos com perda auditiva. Em seguida foi realizada a manobra de Dix-Hallpike e vectoeletronistagmogra [...] fia. Aplicou-se o Teste Qui-Quadrado e Exato de Fisher para análise estatística, com significância de 5% (p=0,050). RESULTADOS: compuseram a amostra 26 sujeitos do gênero masculino (86,7%) e 4 feminino (13,3%), com idade variando entre 24 e 35 anos. Destes, 13 sujeitos (43,4%) apresentaram exame vestibular normal, enquanto os demais (56,6%) apresentaram alteração na prova calórica, com maior ocorrência de disfunção vestibular periférica seguida de disfunção vestibular periférica deficitária unilateral. Não houve diferença estatisticamente significante quanto à presença de alteração vestibular nem quanto à classificação dessas alterações. Comprovou-se significante diferença para queixa de tontura entre os gêneros, sendo o feminino mais propenso a apresentá-la. Não houve diferença estatisticamente significante quanto à queixa de tontura entre as faixas etárias avaliadas, havendo, entretanto, uma tendência maior para os indivíduos de idade mais elevada a apresentarem. Não houve relação estatisticamente significante entre disfunção vestibular e queixas de tontura, manifestações auditivas nem antecedentes patológicos. CONCLUSÕES: não foi encontrada uma relação estatisticamente relevante entre o grupo estudado e a alteração vestibular. Todavia, entre os bombeiros que apresentaram alteração, houve maior ocorrência de disfunção vestibular periférica seguida de disfunção vestibular periférica deficitária unilateral, sem diferença estatisticamente significante entre elas. Os bombeiros apresentaram queixas de tontura, manifestações auditivas e antecedentes patológicos sem relação estatisticamente significante com as disfunções vestibulares identificadas. Abstract in english PURPOSES: to investigate the frequency of vestibular disorders in firefighters working in Alagoas and their complaints. METHODS: we performed otoneurologic interviews and audiological evaluation, discarding the sample subjects with abnormal results. The valid sample was underwent the maneuver Di [...] x-Hallpike and vectoelectronystagmography. We used the Chi-square test and Fisher Exact test for statistical analysis, with significance level of 5% (p = 0.050). RESULTS: the sample consisted by 26 male (86.7%) and 4 female subjects (13.3%) with aged between 24 and 35 years. Of these, were found 43.4% results normal and 56.6% showed abnormalities in the caloric test, with a higher incidence of peripheral vestibular dysfunction followed by unilateral peripheral vestibular deficit dysfunction. There were no statistically significant differences in the presence of vestibular disorders or in the classification of these pathologies. Was perceived effective difference for dizziness between genders, with females more likely to present it. There was no statistically significant difference regarding dizziness between the age groups, with a tendency for older subjects present it more. There was no statistically significant relationship between vestibular disorder and complaints of dizziness, auditory manifestations or history of disease. CONCLUSIONS: there was a higher incidence of peripheral vestibular dysfunction followed by unilateral peripheral vestibular deficit dysfunction, without statistically significant difference between them. The examined firefighters complained of dizziness, auditory manifestations and pathological history, but without statistically significant relationship with vestibular disorders.

Ana Carla Lima, Barbosa; Ilka do Amaral, Soares; Elizângela Dias, Camboim.

1443-14-01

194

THE DYNAMICS OF IMPULSE ACTIVITY OF THE MEDIAL VESTIBULAR NUCLEUS UNDER CONDITIONS OF VIBRATION IN LABYRINTHECTOMIED RAT  

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Full Text Available The computer analyzes of the inferior vestibular nuclei was performed in norm and after unilateral labyrinthactomy of right site. On 2-d day after oparation, animals were vibrated with diferent period (5, 10 and 15 days. Benchmark analysis of the features of background pulse activity of both nuclei neurons showed initial asymmetry of the impulse average frequency of interspike intervals. After 15 days vibration impulse average frequency was higher on damaged site, than on unstrucked site. The particularities and functional importance our results are discussed.

S.H. Sarkisyan

2012-09-01

195

Changes in Histamine Receptors (H1, H2, and H3) Expression in Rat Medial Vestibular Nucleus and Flocculus after Unilateral Labyrinthectomy: Histamine Receptors in Vestibular Compensation  

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Vestibular compensation is the process of behavioral recovery following peripheral vestibular lesion. In clinics, the histaminergic medicine is the most widely prescribed for the treatment of vertigo and motion sickness, however, the molecular mechanisms by which histamine modulates vestibular function remain unclear. During recovery from the lesion, the modulation of histamine receptors in the medial vestibular nucleus (MVN) and the flocculus may play an important role. Here with the means o...

Zhou, Liuqing; Zhou, Wen; Zhang, Sulin; Liu, Bo; Leng, Yangming; Zhou, Renhong; Kong, Weijia

2013-01-01

196

Vestibular syndrome in giant anteater (Myrmecophaga tridactyla / Síndrome vestibular em tamanduá-bandeira (Myrmecophaga tridactyla  

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Full Text Available The vestibular syndrome is a well-defined disease in domestic animals but little known in wild ones. Here this affection of central origin is described in a caquetic adult female giant anteater (Myrmecophaga tridactyla, which presented circling behavior, extensor hypermetry in thoracic limbs, head tilt and spontaneous horizontal and positional vertical nystagmus. The animal received tube feeding twice daily and dexamethasone was given subcutaneous once daily at the dosis of 6mg/kg, with a progressive improvement of health after the second day of treatment. Dose was reduced to a half from fourth to sixth day, and to a quarter on seventh day, when the animal died. On the fifth day, however, circle deambulation had ceased and hypermetry, head tilt and nystagmus were reduced. Treating vestibular syndrome is a challenge in wild animal practice. Treatment is affected by hyporexia and anorexia, making difficult the animals´ health improvement, which generally present muscle atrophy.A síndrome vestibular é uma afecção bem descrita em animais domésticos e pouco relatada em selvagens. Este relato descreveu essa afecção de origem central em uma fêmea adulta de tamanduá-bandeira (Myrmecophaga tridactyla, caquética, apresentando deambulação em círculos, hipermetria extensora nos membros torácicos, desvio da cabeça e nistagmo espontâneo horizontal e posicional vertical. O animal foi alimentado por sonda oral, 2x/dia e instituiu-se tratamento com dexametasona subcutânea na dose 6mg/kg, 1x/dia, com melhora progressiva a partir da segunda administração. A dose foi diminuída pela metade do quarto ao sexto dia, e reduzida novamente à metade no sétimo dia, quando ocorreu óbito. Entretanto, no quinto dia de tratamento, a deambulação em círculos foi interrompida, e a hipermetria, desvio da cabeça e nistagmo diminuídos. O tratamento de animais selvagens com síndrome vestibular é um desafio e é prejudicado pela hiporexia ou anorexia, dificultando a recuperação dos mesmos, que geralmente apresentam diminuição da massa muscular.

Leandro Luís Martins

2009-10-01

197

Vestibular Migraine has Higher Correlation with Carsickness than Non-vestibular Migraine and Meniere's Disease.  

Science.gov (United States)

Purpose: To investigate whether patients with vestibular migraine (VM) are more susceptible to carsickness than patients with non-vestibular migraine (NVM) or Meniere's disease (MD). Methods: Consecutive patients with a diagnosis of definite VM, probable VM, NVM, or MD at our Headache and Dizziness clinics were interviewed using the same three questions to investigate the history of carsickness. The patients who had experienced carsickness in their lifetime and those who had still experienced carsickness in the past ten years were identified. The rates of carsickness were compared between groups. Results: 78.4% of the VM patients had experienced carsickness in their lifetime, which was significantly higher than the patients with NVM (43.6%) and MD (18.2%). Both the lifetime rate of carsickness and the rate in the past ten years were highest in the patients with definite VM, followed by probable VM, NVM, and MD (p less than 0.05, chi-square test). The odds ratio of lifetime carsickness for VM versus MD was high (8.7). Conclusion: Both patients with definite VM and probable VM were more susceptible to carsickness than the patients with NVM or MD. This reinforces the theory of vestibular hypersensitivity in VM. We suggest that a past history of carsickness may help in the diagnosis of VM, and especially in distinguishing VM from MD. PMID:24833209

Chang, Tzu-Pu; Hsu, Yung-Chu

2014-03-01

198

Nitric Oxide Signaling in Hypergravity-Induced Neuronal Plasticity  

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The goal of this research project was to identify the neurons and circuits in the vestibular nuclei and nucleus prepositus hypoglossi that utilize nitric oxide (NO) for intercellular signaling during gravity-induced plasticity. This objective was pursued using histochemical and immunocytochemical approaches to localize NO-producing neurons and characterize the fine morphology of the cells in ground-based studies of normal rats, rats adapted to hypergravity, and rats adapted to hypergravity and then re-adapted to the 1G environment. NO-producing neurons were identified and studied using four methodologies: i) immunocytochemistry employing polyclonal antibodies directed against neuronal nitric oxide synthase (nNOS), to provide an indication of the capacity of a cell for NO production; ii) immunocytochemistry employing a monoclonal antibody directed against L-citrulline, to provide an indirect index of the enzyme's activity; iii) histochemistry based on the NADPH-diaphorase reaction, for fuI1 cytological visualization of neurons; and iv) double immunofluorescence to co-localize nNOS and L-citrulline in individual vestibular nuclei (VN) and neurons.

Holstein, Gay R.

2003-01-01

199

Mechanism of spontaneous activity in afferent neurons of the zebrafish lateral-line organ  

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Many auditory, vestibular, and lateral-line afferent neurons display spontaneous action potentials. This spontaneous spiking is thought to result from hair-cell glutamate release in the absence of stimuli. Spontaneous release at hair-cell resting potentials presumably results from CaV1.3 L-type calcium channel activity. Here, using intact zebrafish larvae, we recorded robust spontaneous spiking from lateral-line afferent neurons in the absence of external stimuli. Consistent with the above as...

Trapani, Josef G.; Nicolson, Teresa

2011-01-01

200

Distinct spontaneous shrinkage of a sporadic vestibular schwannoma  

DEFF Research Database (Denmark)

We present a case with outspoken spontaneous vestibular schwannoma shrinkage and review the related literature. The patient was initially diagnosed with a left-sided, intrameatal vestibular schwannoma, which subsequently grew into the cerebello-pontine angle (CPA), followed by total shrinkage of the CPA component without any intervention over a 12-year observation period. The literature on spontaneous tumor shrinkage was retrieved by searching the subject terms "vestibular schwannoma, conservative management" in PubMed/MEDLINE database, without a time limit. Of the published data, the articles on "shrinkage" or "negative growth" or "regression" or "involution" of the tumor were selected, and the contents on the rate, extent and mechanism of spontaneous tumor shrinkage were extracted and reviewed. The reported rate of spontaneous shrinkage of vestibular schwannoma is 5-10% of patients managed conservatively. Extreme shrinkage of the tumor may occur spontaneously.

Huang, Xiaowen; Cayé-Thomasen, Per

2013-01-01

 
 
 
 
201

Telefones celulares: influência nos sistemas auditivo e vestibular / Mobile phones: influence on auditory and vestibular systems  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Os sistemas de telecomunicações emitem radiofreqüência, uma radiação eletromagnética invisível. Telefones celulares transmitem microondas (450900 MHz no sistema analógico e 1,82,2 GHz no sistema digital), muito próximo à orelha do usuário. Esta energia é absorvida pela pele, orelha interna, nervo ve [...] stibulococlear e superfície do lobo temporal. OBJETIVO: Revisar a literatura sobre influência dos telefones celulares na audição e equilíbrio. FORMA DE ESTUDO: Revisão sistemática. METODOLOGIA: Foram pesquisados artigos nas bases Lilacs e Medline sobre a influência dos telefones celulares nos sistemas auditivo e vestibular, publicados de 2000 a 2005, e também materiais veiculados na Internet. RESULTADOS: Os estudos sobre radiação do telefone celular e risco de neurinoma do acústico apresentam resultados contraditórios. Alguns autores não encontram maior probabilidade de aparecimento do tumor nos usuários de celulares, enquanto outros relatam que a utilização de telefones analógicos por 10 anos ou mais aumenta o risco para o tumor. A exposição aguda às microondas emitidas pelo celular não influencia a atividade das células ciliadas externas da cóclea, in vivo e in vitro, a condução elétrica no nervo coclear, nem a fisiologia do sistema vestibular em humanos. As próteses auditivas analógicas são mais suscetíveis à interferência eletromagnética dos telefones celulares digitais. CONCLUSÃO: Não há comprovação de lesão cocleovestibular pelos telefones celulares. Abstract in english Telecommunications systems emit radiofrequency, which is an invisible electromagnetic radiation. Mobile phones operate with microwaves (450900 MHz in the analog service, and 1,82,2 GHz in the digital service) very close to the user’s ear. The skin, inner ear, cochlear nerve and the temporal lobe sur [...] face absorb the radiofrequency energy. AIM: literature review on the influence of cellular phones on hearing and balance. STUDY DESIGN: systematic review. METHODS: We reviewed papers on the influence of mobile phones on auditory and vestibular systems from Lilacs and Medline databases, published from 2000 to 2005, and also materials available in the Internet. RESULTS: Studies concerning mobile phone radiation and risk of developing an acoustic neuroma have controversial results. Some authors did not see evidences of a higher risk of tumor development in mobile phone users, while others report that usage of analog cellular phones for ten or more years increase the risk of developing the tumor. Acute exposure to mobile phone microwaves do not influence the cochlear outer hair cells function in vivo and in vitro, the cochlear nerve electrical properties nor the vestibular system physiology in humans. Analog hearing aids are more susceptible to the electromagnetic interference caused by digital mobile phones. CONCLUSION: there is no evidence of cochleo-vestibular lesion caused by cellular phones.

Aracy Pereira Silveira, Balbani; Jair Cortez, Montovani.

2008-02-01

202

Telefones celulares: influência nos sistemas auditivo e vestibular Mobile phones: influence on auditory and vestibular systems  

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Full Text Available Os sistemas de telecomunicações emitem radiofreqüência, uma radiação eletromagnética invisível. Telefones celulares transmitem microondas (450900 MHz no sistema analógico e 1,82,2 GHz no sistema digital, muito próximo à orelha do usuário. Esta energia é absorvida pela pele, orelha interna, nervo vestibulococlear e superfície do lobo temporal. OBJETIVO: Revisar a literatura sobre influência dos telefones celulares na audição e equilíbrio. FORMA DE ESTUDO: Revisão sistemática. METODOLOGIA: Foram pesquisados artigos nas bases Lilacs e Medline sobre a influência dos telefones celulares nos sistemas auditivo e vestibular, publicados de 2000 a 2005, e também materiais veiculados na Internet. RESULTADOS: Os estudos sobre radiação do telefone celular e risco de neurinoma do acústico apresentam resultados contraditórios. Alguns autores não encontram maior probabilidade de aparecimento do tumor nos usuários de celulares, enquanto outros relatam que a utilização de telefones analógicos por 10 anos ou mais aumenta o risco para o tumor. A exposição aguda às microondas emitidas pelo celular não influencia a atividade das células ciliadas externas da cóclea, in vivo e in vitro, a condução elétrica no nervo coclear, nem a fisiologia do sistema vestibular em humanos. As próteses auditivas analógicas são mais suscetíveis à interferência eletromagnética dos telefones celulares digitais. CONCLUSÃO: Não há comprovação de lesão cocleovestibular pelos telefones celulares.Telecommunications systems emit radiofrequency, which is an invisible electromagnetic radiation. Mobile phones operate with microwaves (450900 MHz in the analog service, and 1,82,2 GHz in the digital service very close to the user’s ear. The skin, inner ear, cochlear nerve and the temporal lobe surface absorb the radiofrequency energy. AIM: literature review on the influence of cellular phones on hearing and balance. STUDY DESIGN: systematic review. METHODS: We reviewed papers on the influence of mobile phones on auditory and vestibular systems from Lilacs and Medline databases, published from 2000 to 2005, and also materials available in the Internet. RESULTS: Studies concerning mobile phone radiation and risk of developing an acoustic neuroma have controversial results. Some authors did not see evidences of a higher risk of tumor development in mobile phone users, while others report that usage of analog cellular phones for ten or more years increase the risk of developing the tumor. Acute exposure to mobile phone microwaves do not influence the cochlear outer hair cells function in vivo and in vitro, the cochlear nerve electrical properties nor the vestibular system physiology in humans. Analog hearing aids are more susceptible to the electromagnetic interference caused by digital mobile phones. CONCLUSION: there is no evidence of cochleo-vestibular lesion caused by cellular phones.

Aracy Pereira Silveira Balbani

2008-02-01

203

Early and phasic cortical metabolic changes in vestibular neuritis onset.  

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Functional brain activation studies described the presence of separate cortical areas responsible for central processing of peripheral vestibular information and reported their activation and interactions with other sensory modalities and the changes of this network associated to strategic peripheral or central vestibular lesions. It is already known that cortical changes induced by acute unilateral vestibular failure (UVF) are various and undergo variations over time, revealing different cortical involved areas at the onset and recovery from symptoms. The present study aimed at reporting the earliest change in cortical metabolic activity during a paradigmatic form of UVF such as vestibular neuritis (VN), that is, a purely peripheral lesion of the vestibular system, that offers the opportunity to study the cortical response to altered vestibular processing. This research reports [(18)F]fluorodeoxyglucose positron emission tomography brain scan data concerning the early cortical metabolic activity associated to symptoms onset in a group of eight patients suffering from VN. VN patients' cortical metabolic activity during the first two days from symptoms onset was compared to that recorded one month later and to a control healthy group. Beside the known cortical response in the sensorimotor network associated to vestibular deafferentation, we show for the first time the involvement of Entorhinal (BAs 28, 34) and Temporal (BA 38) cortices in early phases of symptomatology onset. We interpret these findings as the cortical counterparts of the attempt to reorient oneself in space counteracting the vertigo symptom (Bas 28, 34) and of the emotional response to the new pathologic condition (BA 38) respectively. These interpretations were further supported by changes in patients' subjective ratings in balance, anxiety, and depersonalization/derealization scores when tested at illness onset and one month later. The present findings contribute in expanding knowledge about early, fast-changing, and complex cortical responses to pathological vestibular unbalanced processing. PMID:23505435

Alessandrini, Marco; Pagani, Marco; Napolitano, Bianca; Micarelli, Alessandro; Candidi, Matteo; Bruno, Ernesto; Chiaravalloti, Agostino; Di Pietro, Barbara; Schillaci, Orazio

2013-01-01

204

Vestibular impairment in patients with Charcot-Marie-Tooth disease  

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OBJECTIVE: This case-control study aimed to determine whether the imbalance in Charcot-Marie-tooth (CMT) disease is caused only by reduced proprioceptive input or whether the involvement of the vestibular nerve is an additional factor. METHODS: Fifteen patients with CMT disease (aged 48 ± 17 years; 8 women) underwent cervical vestibular-evoked myogenic potentials, which reflect otolith-spinal reflex function, and quantitative horizontal search-coil head-impulse testing, which assesses the h...

Poretti, A.; Palla, A.; Tarnutzer, A. A.; Petersen, J. A.; Weber, K. P.; Straumann, D.; Jung, H. H.

2013-01-01

205

Eye position dependency of nystagmus during constant vestibular stimulation.  

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Alexander's law, the eye position dependency of nystagmus due to peripheral vestibular lesions, has been hypothesized to occur due to adaptive changes in the brainstem velocity-to-position neural integrator in response to non-reciprocal vestibular stimulation. We investigated whether it develops during passive head rotations that produce constant nystagmus for >35 s. The yaw rotation stimulus consisted of a 1-s acceleration (100°/s(2)), followed by a lower acceleration ramp (starting at 7.3?...

Bockisch, C. J.; Khojasteh, E.; Straumann, D.; Hegemann, S. C. A.

2013-01-01

206

Vestibular information is required for dead reckoning in the rat.  

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Dead reckoning is an on-line form of spatial navigation used by an animal to identify its present location and return directly to a starting location, even after circuitous outward trips. At present, it is not known which of several self-movement cues (efferent copy from movement commands, proprioceptive information, sensory flow, or vestibular information) are used to compute homeward trajectories. To determine whether vestibular information is important for dead reckoning, the impact of chemical labyrinthectomy was evaluated in a test that demanded on-line computation of a homeward trajectory. Rats were habituated to leave a refuge that was visible from all locations on a circular table to forage for large food pellets, which they carried back to the refuge to eat. Two different probe trials were given: (1) the rats foraged from the same spatial location from a hidden refuge in the light and so were able to use visual cues to navigate; (2) the same procedure took place in the dark, constraining the animals to dead reckon. Although control rats carried food directly and rapidly back to the refuge on both probes, the rats with vestibular lesions were able to do so on the hidden refuge but not on the dark probe. The scores of vestibular reflex tests predicted the dead reckoning deficit. The vestibular animals were also impaired in learning a new piloting task. This is the first unambiguous demonstration that vestibular information is used in dead reckoning and also contributes to piloting. PMID:12427858

Wallace, Douglas G; Hines, Dustin J; Pellis, Sergio M; Whishaw, Ian Q

2002-11-15

207

Preservation of auditory and vestibular function after surgical removal of bilateral vestibular schwannomas in a patient with neurofibromatosis type 2  

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The outcome of acoustic neuroma (vestibular schwannoma) surgery continues to improve rapidly. Advances can be attributed to several fields, but the most important contributions have arisen from the identification of the genes responsible for the dominant inheritance of neurofibromatosis types 1 (NF1) and 2 (NF2) and the development of magnetic resonance imaging with gadolinium enhancement for the early anatomic confirmation of the pathognomonic, bilateral vestibular schwannomas in NF2. These advances enable early diagnosis and treatment when the tumors are small in virtually all subjects at risk for NF2. The authors suggest that advising young NF2 patients to wait until complications develop, especially hearing loss, before diagnosing and operating for bilateral eighth nerve schwannomas may not always be in the best interest of the patient. To the authors' knowledge, this is the first reported case of preservation of both auditory and vestibular function in a patient after bilateral vestibular schwannoma excision.

Black, F. O.; Brackmann, D. E.; Hitselberger, W. E.; Purdy, J.

1995-01-01

208

Avaliação do efeito da cafeína no teste vestibular / Evaluation of the caffeine effect in the vestibular test  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Há controvérsias sobre a interferência da cafeína no teste vestibular. O café é a fonte mais rica em cafeína. Enquanto em alguns serviços os pacientes são orientados a suspender a ingestão de café 24 a 48 horas antes da realização do teste, outros não consideram necessária a suspensão da ingestão de [...] ssa bebida. OBJETIVO: Avaliar o efeito da cafeína no resultado do teste vestibular. FORMA DE ESTUDO: clínico com coorte transversal. MATERIAL E MÉTODO: Estudo comparativo, transversal, pareado. O teste vestibular foi realizado em duplicidade, com intervalo máximo de cinco dias entre um e outro exame. No primeiro teste, os pacientes foram orientados a não ingerir café 24 horas antes do exame; no segundo teste, os pacientes foram orientados a beber café como de costume. Todos os participantes tinham indicação clínica de se submeter ao teste vestibular e tinham o hábito de tomar café. RESULTADOS: Participaram do estudo 19 mulheres com idade média de 49,5 anos. O consumo médio de café foi de três xícaras por dia. As queixas de ansiedade e cefaléia foram associadas ao teste realizado com suspensão do café. Não houve diferença estatisticamente significante nos resultados dos exames realizados com e sem ingestão de café. CONCLUSÃO: A ingestão moderada de café não interferiu no resultado do teste vestibular. Considerando ser recomendável que o paciente esteja tranqüilo ao se submeter ao teste vestibular e que a meia-vida da cafeína é de apenas seis horas, sugerimos que a orientação para a suspensão súbita e completa da ingestão moderada de café antes do teste vestibular para os indivíduos habituados à ingestão diária seja reavaliada. Abstract in english Exist controversy about the interference of the caffeine in the vestibular test. Coffee is the richest source of caffeine. While in some services, the patients were orient to suspend the ingestion of caffeine 24 to 48 hours before the vestibular test, other not consider the suspension of this drink [...] necessary. AIM: To evaluate the effect of caffeine in the vestibular test result. STUDY DESIGN: clinical with transversal cohort. MATERIAL AND METHOD: Seccional and matched research. The vestibular test was performed twice in the same patient, with five days interval between the exams. In the first test, the patient did not drink coffee 24 hours before the exam; in the second, the patient drunk coffee as usual. All of the participants had clinical indication for vestibular test and were used to drinking coffee. RESULTS: Nineteen women, medium age of 49,5 years, participated. The average coffee consumption was three cups per day. The complaints of anxiety and headache were associated with the submission to the vestibular test without coffee. The exams were not statistically different comparing the results of the tests performed with and without the coffee ingestion. CONCLUSION: The moderate ingestion of coffee was not shown to interfere in the results of the vestibular test. Considering that it is recommended that the patient be calm to be submitted to the vestibular test and that the half-life of the caffeine is only of six hours, we suggest that the orientation of complete and abrupt drinking coffee suspension of moderate dose before the vestibular test for the individuals used to daily drinking coffee be reevaluated.

Lilian, Felipe; Lilia Correia, Simões; Denise Utsch, Gonçalves; Patrícia Cotta, Mancini.

2005-12-01

209

Avaliação do efeito da cafeína no teste vestibular Evaluation of the caffeine effect in the vestibular test  

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Full Text Available Há controvérsias sobre a interferência da cafeína no teste vestibular. O café é a fonte mais rica em cafeína. Enquanto em alguns serviços os pacientes são orientados a suspender a ingestão de café 24 a 48 horas antes da realização do teste, outros não consideram necessária a suspensão da ingestão dessa bebida. OBJETIVO: Avaliar o efeito da cafeína no resultado do teste vestibular. FORMA DE ESTUDO: clínico com coorte transversal. MATERIAL E MÉTODO: Estudo comparativo, transversal, pareado. O teste vestibular foi realizado em duplicidade, com intervalo máximo de cinco dias entre um e outro exame. No primeiro teste, os pacientes foram orientados a não ingerir café 24 horas antes do exame; no segundo teste, os pacientes foram orientados a beber café como de costume. Todos os participantes tinham indicação clínica de se submeter ao teste vestibular e tinham o hábito de tomar café. RESULTADOS: Participaram do estudo 19 mulheres com idade média de 49,5 anos. O consumo médio de café foi de três xícaras por dia. As queixas de ansiedade e cefaléia foram associadas ao teste realizado com suspensão do café. Não houve diferença estatisticamente significante nos resultados dos exames realizados com e sem ingestão de café. CONCLUSÃO: A ingestão moderada de café não interferiu no resultado do teste vestibular. Considerando ser recomendável que o paciente esteja tranqüilo ao se submeter ao teste vestibular e que a meia-vida da cafeína é de apenas seis horas, sugerimos que a orientação para a suspensão súbita e completa da ingestão moderada de café antes do teste vestibular para os indivíduos habituados à ingestão diária seja reavaliada.Exist controversy about the interference of the caffeine in the vestibular test. Coffee is the richest source of caffeine. While in some services, the patients were orient to suspend the ingestion of caffeine 24 to 48 hours before the vestibular test, other not consider the suspension of this drink necessary. AIM: To evaluate the effect of caffeine in the vestibular test result. STUDY DESIGN: clinical with transversal cohort. MATERIAL AND METHOD: Seccional and matched research. The vestibular test was performed twice in the same patient, with five days interval between the exams. In the first test, the patient did not drink coffee 24 hours before the exam; in the second, the patient drunk coffee as usual. All of the participants had clinical indication for vestibular test and were used to drinking coffee. RESULTS: Nineteen women, medium age of 49,5 years, participated. The average coffee consumption was three cups per day. The complaints of anxiety and headache were associated with the submission to the vestibular test without coffee. The exams were not statistically different comparing the results of the tests performed with and without the coffee ingestion. CONCLUSION: The moderate ingestion of coffee was not shown to interfere in the results of the vestibular test. Considering that it is recommended that the patient be calm to be submitted to the vestibular test and that the half-life of the caffeine is only of six hours, we suggest that the orientation of complete and abrupt drinking coffee suspension of moderate dose before the vestibular test for the individuals used to daily drinking coffee be reevaluated.

Lilian Felipe

2005-12-01

210

Avaliação do efeito da cafeína no teste vestibular / Evaluation of the caffeine effect in the vestibular test  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Há controvérsias sobre a interferência da cafeína no teste vestibular. O café é a fonte mais rica em cafeína. Enquanto em alguns serviços os pacientes são orientados a suspender a ingestão de café 24 a 48 horas antes da realização do teste, outros não consideram necessária a suspensão da ingestão de [...] ssa bebida. OBJETIVO: Avaliar o efeito da cafeína no resultado do teste vestibular. FORMA DE ESTUDO: clínico com coorte transversal. MATERIAL E MÉTODO: Estudo comparativo, transversal, pareado. O teste vestibular foi realizado em duplicidade, com intervalo máximo de cinco dias entre um e outro exame. No primeiro teste, os pacientes foram orientados a não ingerir café 24 horas antes do exame; no segundo teste, os pacientes foram orientados a beber café como de costume. Todos os participantes tinham indicação clínica de se submeter ao teste vestibular e tinham o hábito de tomar café. RESULTADOS: Participaram do estudo 19 mulheres com idade média de 49,5 anos. O consumo médio de café foi de três xícaras por dia. As queixas de ansiedade e cefaléia foram associadas ao teste realizado com suspensão do café. Não houve diferença estatisticamente significante nos resultados dos exames realizados com e sem ingestão de café. CONCLUSÃO: A ingestão moderada de café não interferiu no resultado do teste vestibular. Considerando ser recomendável que o paciente esteja tranqüilo ao se submeter ao teste vestibular e que a meia-vida da cafeína é de apenas seis horas, sugerimos que a orientação para a suspensão súbita e completa da ingestão moderada de café antes do teste vestibular para os indivíduos habituados à ingestão diária seja reavaliada. Abstract in english Exist controversy about the interference of the caffeine in the vestibular test. Coffee is the richest source of caffeine. While in some services, the patients were orient to suspend the ingestion of caffeine 24 to 48 hours before the vestibular test, other not consider the suspension of this drink [...] necessary. AIM: To evaluate the effect of caffeine in the vestibular test result. STUDY DESIGN: clinical with transversal cohort. MATERIAL AND METHOD: Seccional and matched research. The vestibular test was performed twice in the same patient, with five days interval between the exams. In the first test, the patient did not drink coffee 24 hours before the exam; in the second, the patient drunk coffee as usual. All of the participants had clinical indication for vestibular test and were used to drinking coffee. RESULTS: Nineteen women, medium age of 49,5 years, participated. The average coffee consumption was three cups per day. The complaints of anxiety and headache were associated with the submission to the vestibular test without coffee. The exams were not statistically different comparing the results of the tests performed with and without the coffee ingestion. CONCLUSION: The moderate ingestion of coffee was not shown to interfere in the results of the vestibular test. Considering that it is recommended that the patient be calm to be submitted to the vestibular test and that the half-life of the caffeine is only of six hours, we suggest that the orientation of complete and abrupt drinking coffee suspension of moderate dose before the vestibular test for the individuals used to daily drinking coffee be reevaluated.

Lilian, Felipe; Lilia Correia, Simões; Denise Utsch, Gonçalves; Patrícia Cotta, Mancini.

211

Pesquisa da função vestibular em crianças com queixa de dificuldades escolares Vestibular function in children underperforming at school  

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Full Text Available O aprendizado é um processo complexo, dinâmico, estruturado a partir de um ato motor e perceptivo, que, elaborado corticalmente, dá origem à cognição. O equilíbrio é função neurológica importante para a manutenção de posturas adequadas, imprescindíveis no ato de aprender, indicativo de maturidade neurológica. OBJETIVO: Estudar a função vestibular em crianças com dificuldades escolares. ESTUDO DE CASO: Estudo clínico com coorte transversal. MATERIAL E MÉTODO: Foram estudadas 88 crianças entre 7 e 12 anos, que freqüentavam escolas públicas da cidade de Piracicaba durante os anos de 2004 e 2006. Os procedimentos utilizados foram: a anamnese; exame otorrinolaringológico; exame audiológico e avaliação vestibular. RESULTADOS: Das crianças avaliadas, 51,0% não relataram dificuldades escolares e 49,0% referiram ter dificuldades escolares. Encontramos 73,3% de exame vestibular normal nas crianças sem dificuldades escolares e 32,6% de normalidade nas crianças com dificuldades escolares. Encontramos alterações vestibulares de origem periférica irritativa tanto unilateral como bilateral, perfazendo um total de 67,4% para as crianças com dificuldades escolares e um total de 26,7% para crianças sem dificuldades escolares. CONCLUSÃO: Todas as alterações vestibulares encontradas foram de origem periférica irritativa. Os dados revelaram uma relação estatisticamente significante nas crianças com dificuldades escolares.Learning is a complex, dynamic process, structured from motor and perception skills which, when cortically processed, give birth to cognition. Balance is a fundamental neurological function that helps us maintain proper postures, an essential factor in learning and a sign or neurologic maturity. AIM: this paper aims to study vestibular function in children underperforming at school. STUDY DESIGN: this is a cross-sectional study. MATERIALS AND METHOD: eighty-eight children with ages ranging between 7 and 12 years attending the public schools of Piracicaba from 2004 to 2006 were enrolled. All children were interviewed, submitted to ENT examination, hearing tests, and vestibular examination. RESULTS: fifty-one percent of the participants had no reported difficulties at school, whereas 49.0% were underperforming at school. Under vestibular examination, 73.3% of the children performing well at school had normal findings, whereas 32.6% of the underperforming children had normal test results. Unilateral and bilateral irritative peripheral vestibular alterations were found in 67.4% of the underperformers and in 26.7% of the children not experiencing difficulties at school. CONCLUSION: all vestibular alterations found had an irritative peripheral origin. There was a statistically significant association between vestibular alteration and poor performance at school.

Eloisa Sartori Franco

2008-12-01

212

Pesquisa da função vestibular em crianças com queixa de dificuldades escolares / Vestibular function in children underperforming at school  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O aprendizado é um processo complexo, dinâmico, estruturado a partir de um ato motor e perceptivo, que, elaborado corticalmente, dá origem à cognição. O equilíbrio é função neurológica importante para a manutenção de posturas adequadas, imprescindíveis no ato de aprender, indicativo de maturidade ne [...] urológica. OBJETIVO: Estudar a função vestibular em crianças com dificuldades escolares. ESTUDO DE CASO: Estudo clínico com coorte transversal. MATERIAL E MÉTODO: Foram estudadas 88 crianças entre 7 e 12 anos, que freqüentavam escolas públicas da cidade de Piracicaba durante os anos de 2004 e 2006. Os procedimentos utilizados foram: a anamnese; exame otorrinolaringológico; exame audiológico e avaliação vestibular. RESULTADOS: Das crianças avaliadas, 51,0% não relataram dificuldades escolares e 49,0% referiram ter dificuldades escolares. Encontramos 73,3% de exame vestibular normal nas crianças sem dificuldades escolares e 32,6% de normalidade nas crianças com dificuldades escolares. Encontramos alterações vestibulares de origem periférica irritativa tanto unilateral como bilateral, perfazendo um total de 67,4% para as crianças com dificuldades escolares e um total de 26,7% para crianças sem dificuldades escolares. CONCLUSÃO: Todas as alterações vestibulares encontradas foram de origem periférica irritativa. Os dados revelaram uma relação estatisticamente significante nas crianças com dificuldades escolares. Abstract in english Learning is a complex, dynamic process, structured from motor and perception skills which, when cortically processed, give birth to cognition. Balance is a fundamental neurological function that helps us maintain proper postures, an essential factor in learning and a sign or neurologic maturity. AIM [...] : this paper aims to study vestibular function in children underperforming at school. STUDY DESIGN: this is a cross-sectional study. MATERIALS AND METHOD: eighty-eight children with ages ranging between 7 and 12 years attending the public schools of Piracicaba from 2004 to 2006 were enrolled. All children were interviewed, submitted to ENT examination, hearing tests, and vestibular examination. RESULTS: fifty-one percent of the participants had no reported difficulties at school, whereas 49.0% were underperforming at school. Under vestibular examination, 73.3% of the children performing well at school had normal findings, whereas 32.6% of the underperforming children had normal test results. Unilateral and bilateral irritative peripheral vestibular alterations were found in 67.4% of the underperformers and in 26.7% of the children not experiencing difficulties at school. CONCLUSION: all vestibular alterations found had an irritative peripheral origin. There was a statistically significant association between vestibular alteration and poor performance at school.

Eloisa Sartori, Franco; Ivone, Panhoca.

213

Paroxismia vestibular: estudo clínico e tratamento de oito pacientes / Vestibular paroxysmia: clinical study and treatment of eight patients  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A paroxismia vestibular é uma síndrome de compressão do VIII nervo craniano e foi denominada inicialmente por Janetta "vertigem posicional incapacitante". Esta síndrome é caracterizada por episódios curtos de vertigem, zumbido, déficit vestibular e auditivo. A RM pode mostrar compressão do VIII nerv [...] o por vasos da fossa posterior, como a artéria basilar, artéria vertebral, artéria cerebelar inferior anterior, artéria cerebelar inferior posterior. A paroxismia vestibular pode ser tratada com terapia medicamentosa tais como carbamazepina, fenitoína ou gabapentina, ou com descompressão microvascular do VIII nervo. Este estudo descreve oito pacientes com paroxismia vestibular. Quatro deles mostraram também sinais clínicos sugerindo compressão do V e/ou VII nervos. Sete pacientes tratados com carbamazepina tiveram melhora significativa da vertigem e zumbido. Abstract in english Vestibular paroxysmia is a syndrome of cross-compression of the VIII cranial nerve and was first described by Jannetta who used the term "disabling positional vertigo". This syndrome is characterized by brief attacks of vertigo, tinnitus, vestibular and auditory deficits. MRI may show the VIII nerve [...] compression from vessels in the posterior fossa, such as the basilar, vertebral, anterior-inferior cerebellar or the posterior-inferior cerebellar arteries. Vestibular paroxysmia may be treated either with medical therapy, such as carbamazepine, phenytoin or gabapentin or with the microvascular decompression of the VIII nerve. This study describes eight patients with vestibular paroxysmia. Four of them showed also clinical signs suggesting cross-compression of the V and/or VII nerve. Seven patients treated with carbamazepine had significant improvement of vertigo and tinnitus.

Aline Mizuta Kozoroski, Kanashiro; Paula Levatti, Alexandre; Cristiana Borges, Pereira; Antonio Carlos de Paiva, Melo; Milberto, Scaff.

214

Paroxismia vestibular: estudo clínico e tratamento de oito pacientes / Vestibular paroxysmia: clinical study and treatment of eight patients  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A paroxismia vestibular é uma síndrome de compressão do VIII nervo craniano e foi denominada inicialmente por Janetta "vertigem posicional incapacitante". Esta síndrome é caracterizada por episódios curtos de vertigem, zumbido, déficit vestibular e auditivo. A RM pode mostrar compressão do VIII nerv [...] o por vasos da fossa posterior, como a artéria basilar, artéria vertebral, artéria cerebelar inferior anterior, artéria cerebelar inferior posterior. A paroxismia vestibular pode ser tratada com terapia medicamentosa tais como carbamazepina, fenitoína ou gabapentina, ou com descompressão microvascular do VIII nervo. Este estudo descreve oito pacientes com paroxismia vestibular. Quatro deles mostraram também sinais clínicos sugerindo compressão do V e/ou VII nervos. Sete pacientes tratados com carbamazepina tiveram melhora significativa da vertigem e zumbido. Abstract in english Vestibular paroxysmia is a syndrome of cross-compression of the VIII cranial nerve and was first described by Jannetta who used the term "disabling positional vertigo". This syndrome is characterized by brief attacks of vertigo, tinnitus, vestibular and auditory deficits. MRI may show the VIII nerve [...] compression from vessels in the posterior fossa, such as the basilar, vertebral, anterior-inferior cerebellar or the posterior-inferior cerebellar arteries. Vestibular paroxysmia may be treated either with medical therapy, such as carbamazepine, phenytoin or gabapentin or with the microvascular decompression of the VIII nerve. This study describes eight patients with vestibular paroxysmia. Four of them showed also clinical signs suggesting cross-compression of the V and/or VII nerve. Seven patients treated with carbamazepine had significant improvement of vertigo and tinnitus.

Aline Mizuta Kozoroski, Kanashiro; Paula Levatti, Alexandre; Cristiana Borges, Pereira; Antonio Carlos de Paiva, Melo; Milberto, Scaff.

2005-09-01

215

Correlação entre resultado do exame vestibular e queixas psicológicas autorrelatadas de pacientes com sintomas vestibulares / Correlation between vestibular test results and self-reported psychological complaints of patients with vestibular symptoms  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Fatores cognitivos e emocionais podem afetar o equilíbrio, portanto, condições psiquiátricas são comuns em pacientes otoneurológicos. O tratamento dado ao sujeito vertiginoso pode ser mais influenciado pelo sofrimento e comportamento da doença do que pela gravidade da patologia orgânica. OBJETIVO: E [...] ste estudo teve como objetivo verificar a associação entre os resultados do exame vestibular e queixa psicológica autorrelatada, em indivíduos atendidos no ano de 2009, no serviço de audiologia de um hospital em Porto Alegre. MATERIAL E MÉTODO: Foi realizado um estudo retrospectivo, descritivo-exploratório, consultando-se a base de dados dos softwares VecWin® e VecWin® 2 da marca Neurograff®. Foram investigados os resultados do exame vestibular, as queixas referentes aos sintomas psicológicos relatados espontaneamente e idade, sexo e queixa de vertigem e/ou tontura. O trabalho foi realizado em três etapas: agrupamento, exclusão/inclusão e quantificação. CONCLUSÃO: A faixa etária da amostra, o sexo e a presença ou ausência de vertigem e/ou tontura não foram variáveis de influência sobre o resultado do exame vestibular. Houve associação significativa entre a presença de queixa psicológica autorrelatada e o resultado normal do exame vestibular. Assim, é fundamental que os profissionais deem atenção às questões psicológicas relatadas pelo indivíduo na ocasião da anamnese vestibular. Abstract in english Cognitive and emotional factors may affect balance; psychiatric conditions are a common component in patient dizziness. The treatment of patients with vertigo may be affected to a greater degree by the suffering due to this disease than by the severity of organic changes. OBJECTIVE: This study aimed [...] to investigate associations between vestibular test results and self-reported psychological complaints in patients evaluated during 2009 in an audiology unit at a hospital in Porto Alegre. METHODS: We conducted a retrospective, descriptive-exploratory study of data taken from a database of the software VecWin® and VecWin® 2, developed by Neurograff®. We investigated vestibular test results, reports of psychological symptoms reported spontaneously, and information such as age, sex and the presence of vertigo and/or dizziness. This study consisted of three steps: clustering, exclusion/inclusion and quantification. CONCLUSION: Age and gender and the presence or absence of vertigo and/or dizziness were not variables that influenced the outcomes of vestibular testing. There was a significant association between the presence of self-reported psychological complaints and normal vestibular test results. Thus, it is crucial that professionals pay attention to psychological issues reported by patients when the vestibular history is taken.

Léia Gonçalves, Gurgel; Michelle Ramos, Dourado; Taís de Campos, Moreira; Adriana Jung, Serafini; Isabela Hoffmeister, Menegotto; Caroline Tozzi, Reppold; Cristina Loureiro Chaves, Soldera.

2012-02-01

216

Reabilitação vestibular com realidade virtual na ataxia espinocerebelar / Vestibular rehabilitation with virtual reality in spinocerebellar ataxia  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo do estudo foi verificar os benefícios da reabilitação vestibular (RV) com realidade virtual, por meio de avaliação pré e pós-aplicação da Escala de Equilíbrio de Berg (EEB), em quatro casos de ataxia espinocerebelar (AEC). Os casos foram submetidos aos seguintes procedimentos: anamnese, i [...] nspeção otológica, avaliação vestibular e aplicação da EEB pré e pós-RV, com a realidade virtual representada por meio da utilização de jogos do equipamento Wii Fit. Os casos retratam quatro pacientes com diagnóstico genético de AEC (dois tipo 2, um tipo 3 e um em investigação), sendo três do gênero feminino e um do gênero masculino, na faixa etária de 30 a 62 anos. Os pacientes referiram sintomas otoneurológicos e, no exame vestibular, observou-se a presença de nistagmo semiespontâneo com características centrais, ausência de nistagmo pós-rotatório, hiporreflexia e preponderância direcional do nistagmo assimétrica à prova calórica. Nos casos 1 e 2, os pacientes referiram melhora na coordenação dos movimentos e do equilíbrio corporal, independente do escore na EEB ter demonstrado médio risco para queda, antes e após a realização dos exercícios. No caso 3, o paciente apresentou melhora do escore na EEB, bem como do equilíbrio, apresentando baixo risco para queda. O caso 4 não evidenciou melhora na avaliação após a execução dos exercícios. Este estudo de caso demonstrou a possibilidade da aplicação dos exercícios de RV com estímulos virtuais na AEC, com melhora da coordenação motora e do equilíbrio postural. Abstract in english The purpose of this study was to verify the benefits of the vestibular rehabilitation (VR) with virtual reality through the assessment before and after the application of the Berg Balance Scale (BBS) in four cases of spinocerebellar ataxia (SCA). The cases were underwent the following procedures: an [...] amnesis, ear inspection, vestibular assessment and application of the BBS before and after VR with virtual reality using games from Wii Fit device. The cases describe four patients that were diagnosed with genetically inherited SCA (two type 2, one type 3 and one still under investigation), three of them were female and one was male, with ages ranging from 30 to 62 years. The patients presented otoneurological symptoms and the vestibular test showed the presence of semi-spontaneous nystagmus, absence of post-rotational nystagmus, hyporeflexia, and asymmetric directional preponderance of the nystagmus in the caloric test. Patients from cases 1 and 2 have showed an improvement in motor coordination and in body balance, even though the score presented by the BBS had demonstrated medium risk for falling before and after the exercises. In case 3, the patient's loss of balance and BBS score have improved, presenting low risk of falling; whereas the patient in case 4 did not show any improvement in the assessment after the exercises. This case study shows the applicability of VR exercises with virtual stimuli in SCA with improved motor coordination and postural balance.

Bianca Simone, Zeigelboim; Sandra Dias de, Souza; Heidi, Mengelberg; Hélio Afonso Ghizoni, Teive; Paulo Breno Noronha, Liberalesso.

217

Avaliação oculomotora em pacientes com disfunção vestibular periférica Oculomotor evaluation in patients with peripheral vestibular dysfunction  

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Full Text Available OBJETIVO: Verificar se os parâmetros dos movimentos sacádicos fixos e randomizados, do rastreio pendular e do nistagmo optocinético na vectonistagmografia digital podem apresentar alterações em pacientes com hipótese diagnóstica de disfunção vestibular periférica. MÉTODO: Foram avaliados 60 pacientes, de ambos os sexos, com tontura de origem vestibular periférica e idade entre 12 e 82 anos. Os achados foram comparados com um padrão de normalidade para os parâmetros dos movimentos oculares estudados. RESULTADOS: Os movimentos sacádicos fixos estavam alterados em 100% dos casos quanto à latência e em 35% quanto à velocidade; os randomizados estavam alterados em 100% quanto à latência, em 78,3% quanto à precisão e 1,7% quanto à velocidade; o rastreio pendular apresentou alteração do ganho nas freqüências de 0,1Hz em 15%, 0,2Hz em 21,7% e 0,4Hz em 13,3%; o nistagmo optocinético apresentou alteração da velocidade angular da componente lenta em 1,7% e do ganho em 5%. CONCLUSÕES: A latência e a velocidade dos movimentos sacádicos fixos; a latência, a precisão e a velocidade dos movimentos randomizados; o ganho do rastreio pendular; a velocidade angular da componente lenta e o ganho do nistagmo optocinético na vectonistagmografia digital podem apresentar alterações em pacientes com hipótese diagnóstica de disfunção vestibular periférica.AIM: To assess whether or not the parameters of fixed and randomized saccadic movements, of pendular tracking and of optokinetic nystagmus in the digital vectonystagmography may show abnormalities in patients with possible diagnosis of peripheral vestibular dysfunction. METHOD: 60 patients with dizziness of peripheral vestibular origin, from 12 to 82 years of age, males and females, were evaluated in the Universidade Federal de São Paulo. Ocular movement parameter findings were compared to a normal pattern. RESULTS: Fixed saccadic movements were altered in 100% of the cases as to latency, and in 35.0% of the cases as to speed; the randomized saccadic movements were altered in 100% of the cases as to latency, in 78.3% as to precision, and in 1.7% as to speed; the pendular tracking showed a gain alteration in the frequencies of 0.1 Hz in 15% of the cases, 0.2 Hz in 21.7%, and 0.4 Hz in 13.3%; the optokinetic nystagmus showed an alteration of the angular speed in the slow component in 1.7% of the cases, and in gain in 5.0%. CONCLUSION: Fixed saccadic movement latency and speed, randomized saccadic movement latency, precision and speed, pendular tracking gain, slow component angular speed, and optokinetic nystagmus gain in the digital vectonystagmography may show abnormalities in patients with possible diagnosis of peripheral vestibular dysfunction.

Vanessa Costa Tuma

2006-06-01

218

Avaliação oculomotora em pacientes com disfunção vestibular periférica / Oculomotor evaluation in patients with peripheral vestibular dysfunction  

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Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: Verificar se os parâmetros dos movimentos sacádicos fixos e randomizados, do rastreio pendular e do nistagmo optocinético na vectonistagmografia digital podem apresentar alterações em pacientes com hipótese diagnóstica de disfunção vestibular periférica. MÉTODO: Foram avaliados 60 paciente [...] s, de ambos os sexos, com tontura de origem vestibular periférica e idade entre 12 e 82 anos. Os achados foram comparados com um padrão de normalidade para os parâmetros dos movimentos oculares estudados. RESULTADOS: Os movimentos sacádicos fixos estavam alterados em 100% dos casos quanto à latência e em 35% quanto à velocidade; os randomizados estavam alterados em 100% quanto à latência, em 78,3% quanto à precisão e 1,7% quanto à velocidade; o rastreio pendular apresentou alteração do ganho nas freqüências de 0,1Hz em 15%, 0,2Hz em 21,7% e 0,4Hz em 13,3%; o nistagmo optocinético apresentou alteração da velocidade angular da componente lenta em 1,7% e do ganho em 5%. CONCLUSÕES: A latência e a velocidade dos movimentos sacádicos fixos; a latência, a precisão e a velocidade dos movimentos randomizados; o ganho do rastreio pendular; a velocidade angular da componente lenta e o ganho do nistagmo optocinético na vectonistagmografia digital podem apresentar alterações em pacientes com hipótese diagnóstica de disfunção vestibular periférica. Abstract in english AIM: To assess whether or not the parameters of fixed and randomized saccadic movements, of pendular tracking and of optokinetic nystagmus in the digital vectonystagmography may show abnormalities in patients with possible diagnosis of peripheral vestibular dysfunction. METHOD: 60 patients with dizz [...] iness of peripheral vestibular origin, from 12 to 82 years of age, males and females, were evaluated in the Universidade Federal de São Paulo. Ocular movement parameter findings were compared to a normal pattern. RESULTS: Fixed saccadic movements were altered in 100% of the cases as to latency, and in 35.0% of the cases as to speed; the randomized saccadic movements were altered in 100% of the cases as to latency, in 78.3% as to precision, and in 1.7% as to speed; the pendular tracking showed a gain alteration in the frequencies of 0.1 Hz in 15% of the cases, 0.2 Hz in 21.7%, and 0.4 Hz in 13.3%; the optokinetic nystagmus showed an alteration of the angular speed in the slow component in 1.7% of the cases, and in gain in 5.0%. CONCLUSION: Fixed saccadic movement latency and speed, randomized saccadic movement latency, precision and speed, pendular tracking gain, slow component angular speed, and optokinetic nystagmus gain in the digital vectonystagmography may show abnormalities in patients with possible diagnosis of peripheral vestibular dysfunction.

Vanessa Costa, Tuma; Cristina Freitas, Ganança; Maurício Malavasi, Ganança; Heloisa Helena, Caovilla.

2006-06-01

219

Reabilitação vestibular com realidade virtual na ataxia espinocerebelar / Vestibular rehabilitation with virtual reality in spinocerebellar ataxia  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo do estudo foi verificar os benefícios da reabilitação vestibular (RV) com realidade virtual, por meio de avaliação pré e pós-aplicação da Escala de Equilíbrio de Berg (EEB), em quatro casos de ataxia espinocerebelar (AEC). Os casos foram submetidos aos seguintes procedimentos: anamnese, i [...] nspeção otológica, avaliação vestibular e aplicação da EEB pré e pós-RV, com a realidade virtual representada por meio da utilização de jogos do equipamento Wii Fit. Os casos retratam quatro pacientes com diagnóstico genético de AEC (dois tipo 2, um tipo 3 e um em investigação), sendo três do gênero feminino e um do gênero masculino, na faixa etária de 30 a 62 anos. Os pacientes referiram sintomas otoneurológicos e, no exame vestibular, observou-se a presença de nistagmo semiespontâneo com características centrais, ausência de nistagmo pós-rotatório, hiporreflexia e preponderância direcional do nistagmo assimétrica à prova calórica. Nos casos 1 e 2, os pacientes referiram melhora na coordenação dos movimentos e do equilíbrio corporal, independente do escore na EEB ter demonstrado médio risco para queda, antes e após a realização dos exercícios. No caso 3, o paciente apresentou melhora do escore na EEB, bem como do equilíbrio, apresentando baixo risco para queda. O caso 4 não evidenciou melhora na avaliação após a execução dos exercícios. Este estudo de caso demonstrou a possibilidade da aplicação dos exercícios de RV com estímulos virtuais na AEC, com melhora da coordenação motora e do equilíbrio postural. Abstract in english The purpose of this study was to verify the benefits of the vestibular rehabilitation (VR) with virtual reality through the assessment before and after the application of the Berg Balance Scale (BBS) in four cases of spinocerebellar ataxia (SCA). The cases were underwent the following procedures: an [...] amnesis, ear inspection, vestibular assessment and application of the BBS before and after VR with virtual reality using games from Wii Fit device. The cases describe four patients that were diagnosed with genetically inherited SCA (two type 2, one type 3 and one still under investigation), three of them were female and one was male, with ages ranging from 30 to 62 years. The patients presented otoneurological symptoms and the vestibular test showed the presence of semi-spontaneous nystagmus, absence of post-rotational nystagmus, hyporeflexia, and asymmetric directional preponderance of the nystagmus in the caloric test. Patients from cases 1 and 2 have showed an improvement in motor coordination and in body balance, even though the score presented by the BBS had demonstrated medium risk for falling before and after the exercises. In case 3, the patient's loss of balance and BBS score have improved, presenting low risk of falling; whereas the patient in case 4 did not show any improvement in the assessment after the exercises. This case study shows the applicability of VR exercises with virtual stimuli in SCA with improved motor coordination and postural balance.

Bianca Simone, Zeigelboim; Sandra Dias de, Souza; Heidi, Mengelberg; Hélio Afonso Ghizoni, Teive; Paulo Breno Noronha, Liberalesso.

2013-06-01

220

Neuronal Polarity  

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The assembly of functional neuronal networks in the developing animal relies on the polarization of neurons, i.e., the formation of a single axon and multiple dendrites. Breaking the symmetry of neurons depends on cytoskeletal rearrangements. In particular, axon specification requires local dynamic instability of actin and stabilization of microtubules. The polarized cytoskeleton also provides the basis for selective trafficking and retention of cellular components in the future somatodendrit...

Tahirovic, Sabina; Bradke, Frank

2009-01-01

 
 
 
 
221

Enhancement of Otolith Specific Ocular Responses Using Vestibular Stochastic Resonance  

Science.gov (United States)

Introduction: Astronauts experience disturbances in sensorimotor function after spaceflight during the initial introduction to a gravitational environment, especially after long-duration missions. Our goal is to develop a countermeasure based on vestibular stochastic resonance (SR) that could improve central interpretation of vestibular input and mitigate these risks. SR is a mechanism by which noise can assist and enhance the response of neural systems to relevant, imperceptible sensory signals. We have previously shown that imperceptible electrical stimulation of the vestibular system enhances balance performance while standing on an unstable surface. Methods: Eye movement data were collected from 10 subjects during variable radius centrifugation (VRC). Subjects performed 11 trials of VRC that provided equivalent tilt stimuli from otolith and other graviceptor input without the normal concordant canal cues. Bipolar stochastic electrical stimulation, in the range of 0-1500 microamperes, was applied to the vestibular system using a constant current stimulator through electrodes placed over the mastoid process behind the ears. In the VRC paradigm, subjects were accelerated to 216 deg./s. After the subjects no longer sensed rotation, the chair oscillated along a track at 0.1 Hz to provide tilt stimuli of 10 deg. Eye movements were recorded for 6 cycles while subjects fixated on a target in darkness. Ocular counter roll (OCR) movement was calculated from the eye movement data during periods of chair oscillations. Results: Preliminary analysis of the data revealed that 9 of 10 subjects showed an average increase of 28% in the magnitude of OCR responses to the equivalent tilt stimuli while experiencing vestibular SR. The signal amplitude at which performance was maximized was in the range of 100-900 microamperes. Discussion: These results indicate that stochastic electrical stimulation of the vestibular system can improve otolith specific responses. This will have a significant impact on development of vestibular SR delivery systems to aid recovery of function in astronauts after long-duration spaceflight or in people with balance disorders.

Fiedler, Matthew; De Dios, Yiri E.; Esteves, Julie; Galvan, Raquel; Wood, Scott; Bloomberg, Jacob; Mulavara, Ajitkumar

2011-01-01

222

Click-evoked responses in vestibular afferents in rats.  

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Sound activates not only the cochlea but also the vestibular end organs. Research on this phenomenon led to the discovery of the sound-evoked vestibular myogenic potentials recorded from the sternocleidomastoid muscles (cervical VEMP, or cVEMP). Since the cVEMP offers simplicity and the ability to stimulate each labyrinth separately, its values as a test of human vestibular function are widely recognized. Currently, the cVEMP is interpreted as a test of saccule function based on the assumption that clicks primarily activate the saccule. However, sound activation of vestibular end organs other than the saccule has been reported. To provide the neural basis for interpreting clinical VEMP testing, we employed the broadband clicks used in clinical VEMP testing to examine the sound-evoked responses in a large sample of vestibular afferents in Sprague-Dawley rats. Recordings were made from 924 vestibular afferents from 106 rats: 255 from the anterior canal (AC), 202 from the horizontal canal (HC), 177 from the posterior canal (PC), 207 from the superior vestibular nerve otolith (SO), and 83 from the inferior nerve otolith (IO). Sound sensitivity of each afferent was quantified by computing the cumulative probability of evoking a spike (CPE). We found that clicks activated irregular afferents (normalized coefficient of variation of interspike intervals >0.2) from both the otoliths (81%) and the canals (43%). The order of end organ sound sensitivity was SO = IO > AC > HC > PC. Since the sternocleidomastoid motoneurons receive inputs from both the otoliths and the canals, these results provide evidence of a possible contribution from both of them to the click-evoked cVEMP. PMID:21613592

Zhu, Hong; Tang, Xuehui; Wei, Wei; Mustain, William; Xu, Youguo; Zhou, Wu

2011-08-01

223

Vestibular rehabilitation ameliorates chronic dizziness through the SIRT1 axis  

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Full Text Available Dizziness is a common clinical symptom frequently referred to general neurologists and practitioners. Exercise intervention, in the form of vestibular rehabilitation, is known as an effective clinical management for dizziness. This intervention is reported to have a functional role in correcting dizziness, improving gaze stability, retraining balance and gait and enhancing physical fitness. Dizziness is known to be highly related to inflammation and oxidative stress. SIRT1 is a major molecule for regulation of inflammation and mitigation of oxidative stress in chronic diseases such as atherosclerosis and chronic obstructive pulmonary disease. However, the bio-molecular roles of SIRT1 involved in the pathogenesis of dizziness are still largely unclear. In this study, a total of 30 subjects were recruited (15 patients with chronic dizziness, and 15 age/gender matched non-dizzy control subjects. The dizzy subjects group received 18 sessions of 30-minutes vestibular training. We found that the mRNA and protein expression levels of SIRT1 in the blood samples of chronic dizzy patients were repressed compared with those of healthy controls. After vestibular training, the dizzy patients had significant symptomatic improvements. The SIRT1 expression and its downstream genes (PPAR-? and PGC-1? were upregulated after vestibular exercises in dizzy subjects. Notably, the catalytic activity of SIRT1, NADPH and antioxidant enzyme activities were also activated in dizzy patients after vestibular training. Furthermore, vestibular exercise training reduced oxidative events and p53 expression in patients with dizziness. This study demonstrated that vestibular exercise training improved dizziness symptoms, and mechanisms for alleviation of chronic dizziness may partly involve the activation of the SIRT1 axis and the repression of redox status.

Chung-Lan Kao

2014-03-01

224

Ocular vestibular evoked myogenic potentials in normal-hearing adults  

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Full Text Available Background and Aim: Ocular vestibular-evoked myogenic potential (oVEMP is a novel vestibular function test. This short-latency response can be recorded through contracting extraocular muscles by high-intensity acoustic stimulation and can be used to evaluate contralateral ocular-vestibular reflex. The aim of this study was to record and compare the amplitude, latency, asymmetry ratio and occurrence percentage of oVEMP (n10 and cervical VEMP (p13 responses in a group of normal adult subjects.Methods: We carried out a cross-sectional study on 20 adult subjects' mean age 22.18 years, SD=2.19 with normal hearing sensitivity and no history of vestibular diseases. oVEMP and cVEMP responses in both ears were recorded using air conducted stimuli 500 Hz short tone burst, 95 dB nHL via insert earphone and compared.Results: cVEMP was recorded in all subjects but oVEMP was absent in two subjects. Mean amplitude and latency were 140.77 ?v and 15.56 ms in p13; and 3.18 ?v and 9.32 ms in n10. There were statistically significant differences between p13 and n10 amplitudes (p<0.001.Conclusion: This study showed that occurrence percentage and amplitude of oVEMP were less than those of cVEMP. Since these two tests originate from different sections of vestibular nerve, we can consider them as parallel vestibular function tests and utilize them for evaluation of vestibular disorders.

Mohammad Kamali

2012-06-01

225

Effects of Galvanic vestibular stimulation on cognitive function.  

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Although imaging studies suggest activation of cortical areas by vestibular input, there is little evidence of an adverse effect of non-veridical vestibular input on cognitive function. To test the hypothesis that degraded vestibular afferent input adversely affects cognition, we compared performance on a cognitive test battery in a group undergoing suprathreshold bilateral bipolar Galvanic vestibular stimulation (GVS) with a control group receiving no GVS or subthreshold stimulation. The battery consisted of six cognitive tests as follows: reaction time, dual tasking, Stroop, mental rotation, perspective-taking and matching-to-sample, as well as a simple visuomotor (manual tracking) task. Subjects performed the test battery before, during and after suprathreshold GVS exposure or subthreshold stimulation. Suprathreshold GVS significantly increased error rate for the match-to-sample and perspective-taking tasks relative to the subthreshold group, demonstrating a negative effect of non-veridical vestibular input in these specific cognitive tasks. Reaction time, dual tasking, mental rotation and manual tracking were unaffected by GVS exposure. The adverse effect of suprathreshold GVS on perspective taking but not mental rotation is consistent with imaging studies, which have demonstrated that egocentric mental transformations (perspective taking) occur primarily in cortical areas that receive vestibular input (the parietal-temporal junction and superior parietal lobule), whereas object-based transformations (mental rotation) occur in the frontoparietal region. The increased error rate during the match-to-sample task is likely due to interference with hippocampal processing related to spatial memory, as suggested by imaging studies on vestibular patients. PMID:22076407

Dilda, Valentina; MacDougall, Hamish G; Curthoys, Ian S; Moore, Steven T

2012-01-01

226

Immunohistochemical studies concerning the neuronal cell cycle of the cat using PCNA, Ki-67 and p53 markers.  

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Recent studies about parvovirus replication in mature neurones of cats indicate that even feline neurones do not seem to be terminally differentiated. For further determination of the proliferative capability of feline neurones, an immunohistochemical study investigating the neuronal expression of the cell cycle-related proteins, proliferating cell nuclear antigen (PCNA), Ki-67 and p53 was initiated. Brains of 50 cats of different age and gender, dying of various diseases, were examined. Strong PCNA clone PC10 expression could be observed in neurones of the cerebellar cortex and the vestibular nuclei, whereas entorhinal cortex, lateral geniculate nucleus and cerebral cortex revealed only weak immunolabelling. The PCNA clone 19F4 labelled numerous neurones in vestibular nuclei and some Purkinje cells of the cerebellum. Nuclear expression of Ki-67 was sporadic in the vestibular nuclei, but p53 expression could not be detected anywhere in the feline brain. However, the presence of nuclear PCNA and Ki-67 expression indicates that certain feline neurones are capable of re-entering the cell cycle. PMID:15610484

Gruber, A; Schmidt, P; Url, A

2004-12-01

227

A volumetric comparison of the vestibular nuclei in primates.  

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The volumes of each of the four vestibular nuclei, superior, lateral, medial and descending, were measured in 80 brains from 2 species of Scandentia, 18 species of prosimians, and 26 species of anthropoids. Size indices were calculated by comparing species-specific points to the nucleus volume-body weight allometry in prosimians, where the average prosimian was set at 1.00. The indices range from 1.78 in Saimiri to 0.48 in Gorilla, and the distributions by families overlap partially or completely. The observed trend in size indices is independent of changes in the neocortex and the ventral pons; average indices are 1.35 in New World monkeys, 1.20 in Old World monkeys, 0.74 in apes, 0.82 in man. Among prosimians, Galago, Galagoides and Tarsius (leaping locomotion) show significantly higher indices than Nycticebus, Loris and Perodicticus (slow movement without leaping). The lateral vestibular nuclear indices in Pongidae and man are extremely low, about half of those of the average prosimians. Correlation coefficients of size indices between the vestibular nuclei and other motor nuclei, such as the cerebellar nuclei, ventral pons and striatum, are analysed. The ratio of the vestibular nuclear volumes to the total brain volumes and the distribution of percentages of each vestibular nuclear volume to the total complex are also obtained. PMID:3609971

Matano, S

1986-01-01

228

Isolated floccular infarction: impaired vestibular responses to horizontal head impulse.  

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Isolated floccular infarction is extremely rare, and impairments of the vestibulo-ocular reflex (VOR) have not been explored in humans with isolated floccular lesions. The purpose of this study was to examine and report selective impairment of VOR in response to high acceleration using head impulse in a patient with isolated floccular infarction. The patient underwent bedside and laboratory evaluation of vestibular function, which included video-oculography, ocular torsion and the subjective visual vertical, cervical and ocular vestibular-evoked myogenic potentials, bithermal caloric irrigation, rotatory chair test, and the head impulse test (HIT) using search coils. A 70-year-old woman with a unilateral floccular infarction presented with an acute vestibular syndrome with spontaneous nystagmus beating to the lesion side, impaired ipsilesional pursuit, contraversive ocular torsion and tilt of the subjective visual vertical. With rotatory chair testing at low frequencies, horizontal VOR gains were increased. However, VOR gains were decreased with the higher-frequency, higher-speed HIT. While HIT is often normal in patients with central vestibular disorders, decreased HIT responses do not exclude an isolated cerebellar lesion as a cause of the acute vestibular syndrome. PMID:23370610

Park, Hong-Kyun; Kim, Ji-Soo; Strupp, Michael; Zee, David S

2013-06-01

229

Evaluation of the chemical model of vestibular lesions induced by arsanilate in rats  

International Nuclear Information System (INIS)

Several animal models of vestibular deficits that mimic the human pathology phenotype have previously been developed to correlate the degree of vestibular injury to cognate vestibular deficits in a time-dependent manner. Sodium arsanilate is one of the most commonly used substances for chemical vestibular lesioning, but it is not well described in the literature. In the present study, we used histological and functional approaches to conduct a detailed exploration of the model of vestibular lesions induced by transtympanic injection of sodium arsanilate in rats. The arsanilate-induced damage was restricted to the vestibular sensory organs without affecting the external ear, the oropharynx, or Scarpa's ganglion. This finding strongly supports the absence of diffusion of arsanilate into the external ear or Eustachian tubes, or through the eighth cranial nerve sheath leading to the brainstem. One of the striking observations of the present study is the complete restructuring of the sensory epithelia into a non sensory epithelial monolayer observed at 3 months after arsanilate application. This atrophy resembles the monolayer epithelia observed postmortem in the vestibular epithelia of patients with a history of lesioned vestibular deficits such as labyrinthectomy, antibiotic treatment, vestibular neuritis, or Ménière's disease. In cases of Ménière's disease, aminoglycosides, and platinum-based chemotherapy, vestibular hair cells are destroyed, regardless of the physiopathological process, as reproduced with the arsanilate model of vestibular lesion. These observations, together with those presented in this study of arsanilate vestibular toxicity, suggest that this atrophy process relies on a common mechanism of degeneration of the sensory epithelia.

230

Surgery of vestibular schwannomas: An institutional experience  

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Full Text Available AIMS: To report management results of vestibular schwannomas (VS treated surgically in our institute, with particular reference to completeness of tumor excision, facial nerve and hearing preservation and complications of surgery. STUDY DESIGN AND SETTINGS: Retrospective study of 259 patients treated during the years 1988 to 2002. MATERIALS AND METHODS: The facial nerve function and hearing assessment was done according to House-Brackmann [HB] grading and pure tone audiometry (PTA respectively. All patients were operated by retro-mastoid sub-occipital approach. RESULTS: Most patients had large tumors and had no useful hearing (90%, had disabling cerebellar ataxia (88% and presented with features of raised intra-cranial pressure (45%. Large sized tumors were in 41.3% and giant sized tumors were in 56% cases. Complete tumor excision was carried out in 96.5% and anatomical preservation of facial nerve was achieved in 79.2% cases. Hearing preservation was achieved in 8 patients. Cerebrospinal fluid leak with or without meningitis and transient lower cranial nerve paresis were common complications. The mortality was 6%. CONCLUSIONS: With experience, complete tumor excision with good facial nerve preservation can be achieved in large tumors. Hearing preservation is difficult in bigger tumors. Prevention and control of infection was a major concern.

Jain Vijendra

2005-01-01

231

Microgravity vestibular investigations (10-IML-1)  

Science.gov (United States)

Our perception of how we are oriented in space is dependent on the interaction of virtually every sensory system. For example, to move about in our environment we integrate inputs in our brain from visual, haptic (kinesthetic, proprioceptive, and cutaneous), auditory systems, and labyrinths. In addition to this multimodal system for orientation, our expectations about the direction and speed of our chosen movement are also important. Changes in our environment and the way we interact with the new stimuli will result in a different interpretation by the nervous system of the incoming sensory information. We will adapt to the change in appropriate ways. Because our orientation system is adaptable and complex, it is often difficult to trace a response or change in behavior to any one source of information in this synergistic orientation system. However, with a carefully designed investigation, it is possible to measure signals at the appropriate level of response (both electrophysiological and perceptual) and determine the effect that stimulus rearrangement has on our sense of orientation. The environment of orbital flight represents the stimulus arrangement that is our immediate concern. The Microgravity Vestibular Investigations (MVI) represent a group of experiments designed to investigate the effects of orbital flight and a return to Earth on our orientation system.

Reschke, Millard F.

1992-01-01

232

Nasal Vestibular Huge Keratoacanthoma: An Unusual Site  

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Full Text Available Keratoacanthoma (KA is a rapidly growing, low-grade neoplasm of pilo-sebaceous and hair follicle units which most often appears on the sun-exposed skin of the middle aged and older persons with multiple or localized occurrence. This tumor is dome-shaped nodule with a central keratinous plug. The etiology of this tumor is not obvious. Exposure to excessive sunlight is the most frequently noted responsible factor in the etiology of KA. About 80% of the tumors occur on the face. The histological features of the KA are often very similar to those of a cutaneous squamous cell carcinoma; however, the tumor structure usually provides a basis for their difference. There are many unusual cases of keratoacanthoma reported regarding site, size or other specifications. In this study, we excised a mass of nasal vestibule, a site far away sun-exposure. To our knowledge, this is the first case of nasal vestibular keratoacanthoma. For a clinician and a pathologist it is important to consider a benign lesion like Keratoacanthoma (KA in the differential diagnosis of ulcerated nasal lesions and pay attention to differ it from Squamous Cell Carcinoma (SCC which has a different and aggressive management.

N. Yazdani

2009-01-01

233

Can Vestibular-Evoked Myogenic Potentials Help Differentiate M?ni?re Disease from Vestibular Migraine?  

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Objectives To characterize both cervical and ocular vestibular-evoked myogenic potential (cVEMP, oVEMP) responses to air-conducted sound (ACS) and midline taps in Ménière disease (MD), vestibular migraine (VM), and controls, as well as to determine if cVEMP or oVEMP responses can differentiate MD from VM. Study Design Prospective cohort study. Setting Tertiary referral center. Subjects and Methods Unilateral definite MD patients (n = 20), VM patients (n = 21) by modified Neuhauser criteria, and age-matched controls (n = 28). cVEMP testing used ACS (clicks), and oVEMP testing used ACS (clicks and 500-Hz tone bursts) and midline tap stimuli (reflex hammer and Mini-Shaker). Outcome parameters were cVEMP peak-to-peak amplitudes and oVEMP n10 amplitudes. Results Relative to controls, MD and VM groups both showed reduced click-evoked cVEMP (P .210). Conclusions Using these techniques, VM and MD behaved similarly on most of the VEMP test battery. A link in their pathophysiology may be responsible for these responses. The data suggest a difference in 500-Hz tone burst–evoked oVEMP responses between MD and MV as a group. However, no VEMP test that was investigated segregated individuals with MD from those with VM. PMID:22267492

Zuniga, M. Geraldine; Janky, Kristen L.; Schubert, Michael C.; Carey, John P.

2013-01-01

234

A afecção vestibular infantil: estudo da orientação espacial / Vestibular disorders in childhood: study of spatial disorders  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: verificar como é a percepção do espaço na criança com vertigem periférica. MÉTODOS: estudo prospectivo de 18 crianças, com faixa etária de três a 15 anos, sob acompanhamento no Ambulatório de Otorrinolaringologia / Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo [...] . A percepção espacial foi avaliada por meio de atividade livre (desenho livre) e dirigida (blocos lógicos e teste de Frostig). Das 18 crianças avaliadas, nove constituíram o grupo estudo (diagnóstico de vestibulopatia e queixa de tontura) e nove constituíram o grupo controle (sem história de vestibulopatia e sem queixa de tontura). Foram excluídas crianças que apresentassem comprometimento de Sistema Nervoso Central que interferisse na interpretação da avaliação. Os resultados obtidos foram comparados entre o grupo estudo e controle qualitativamente. RESULTADOS: em relação ao desenho livre, 77,78% das crianças do grupo controle e 55,55% do grupo estudo utilizaram o papel inteiro. Quanto à proporção dos objetos, 100% das crianças do grupo controle e apenas 48,86% das crianças do grupo estudo desenharam com proporção adequada. Nos blocos lógicos, houve maior dificuldade do grupo estudo. No teste de Frostig, foi observada diferença significativa do ponto de vista clínico entre os grupos quanto ao Quociente Perceptual. CONCLUSÃO: as crianças com vestibulopatia, ao desenhar, aproveitaram o papel de forma menos homogênea, com maior dificuldade para desenhar figuras humanas e proporção inadequada entre os objetos. Desta forma, é importante que seja realizado o diagnóstico de vestibulopatia precocemente, para que o tratamento/reabilitação seja iniciado e sintomas, como a desorientação espacial, não influenciem na aprendizagem da criança. Abstract in english PURPOSE: to check how is the child's spatial perception in vestibular disorder. METHODS: prospective study of 18 children, between 3 and 15-year old, under treatment in Ambulatório de Otorrinolaringologia/Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. Space perception w [...] as assessed through a free activity (free drawing) and two directed activities: the Frostig test and an adaptation of the Token Test. Of the 18 evaluated children, 09 composed the study group (diagnosed as having a vestibular disorder) and 09 composed the control group (with no history of vestibular disorder or dizziness). Children who showed central nervous system impairments were excluded. RESULTS: in relation to the free drawing, 77.78% of the control group and 55.55% in the study group used the whole sheet of paper provided. Regarding the proportion of the objects, 100% of the control group showed an adequate proportion in their drawings and it was found in 48.86% of the study group. In the adapted Token Test, the study group showed a major difficulty. In the Frostig test, a small difference between the groups in the Perceptual quotient was observed. CONCLUSION: the children with vestibular disorders, while drawing, used the sheet of paper in a less homogeneous way, showing more difficulty to draw human pictures and an inadequate proportion among the drawn objects. In this way, it is important that the vestibular diagnosis should be done the earliest possible in order to anticipate the treatment/rehabilitation. This may prevent the impairment of spatial perception from negatively influencing the learning process.

Elaine Shizue, Novalo; Maria Valéria Schmidt, Goffi-Gomez; Ítalo Roberto Torres de, Medeiros; Maria Elisabete Bovino, Pedalini; Rosa Maria Rodrigues dos, Santos.

235

Cervical and ocular vestibular-evoked myogenic potentials in vestibular neuritis: comparison between air- and bone-conducted stimulation.  

Science.gov (United States)

To clarify the changes of cervical (cVEMP) and ocular (oVEMP) vestibular evoked myogenic potentials induced by air-conducted sound (ACS) and bone-conducted vibration (BCV) in patients with vestibular neuritis (VN), patients with VN (n = 30) and normal controls (n = 45) underwent recording of cVEMP and oVEMP in response to ACS (1,000 Hz, 5 ms, tone bursts) and BCV (500 Hz, short tone burst). Patients with VN showed a high proportion of oVEMP abnormalities in response to both ACS (80.0 %) and BCV at the forehead (Fz, 73.3 %) or the mastoid (76.7 %). In contrast, cVEMPs were mostly normal with both ACS and BCV in the patients. The dissociations in the abnormalities of cVEMP and oVEMP induced by ACS and BCV at the mastoids and at the forehead in patients with VN suggest that oVEMP reflects functions of the superior vestibular nerve and most likely the utricular function. The results of our study suggest that oVEMP induced by either ACS or BCV appears to depend on integrity of the superior vestibular nerve, possibly due to the utricular afferents travelling in it. In contrast, cVEMP elicited by either ACS or BCV may reflect function of the saccular afferents running in the inferior vestibular nerve. PMID:23670310

Oh, Sun-Young; Kim, Ji-Soo; Yang, Tae-Ho; Shin, Byoung-Soo; Jeong, Seul-Ki

2013-08-01

236

A real-time research platform to study vestibular implants with gyroscopic inputs in vestibular deficient subjects.  

Science.gov (United States)

Researchers have succeeded in partly restoring damaged vestibular functionality in several animal models. Recently, acute interventions have also been demonstrated in human patients. Our previous work on a vestibular implant for humans used predefined stimulation patterns; here we present a research tool that facilitates motion-modulated stimulation. This requires a system that can process gyroscope measurements and send stimulation parameters to a hybrid vestibular-cochlear implant in real-time. To match natural vestibular latencies, the time from sensor input to stimulation output should not exceed 6.5 ms. We describe a system based on National Instrument's CompactRIO platform that can meet this requirement and also offers floating point precision for advanced transfer functions. It is designed for acute clinical interventions, and is sufficiently powerful and flexible to serve as a development platform for evaluating prosthetic control strategies. Amplitude and pulse frequency modulation to predetermined functions or sensor inputs have been validated. The system has been connected to human patients, who each have received a modified MED-EL cochlear implant for vestibular stimulation, and patient tests are ongoing. PMID:25073124

Nguyen, T A Khoa; Ranieri, Maurizio; DiGiovanna, Jack; Peter, Otto; Genovese, Vincenzo; Perez Fornos, Angelica; Micera, Silvestro

2014-08-01

237

Visual gravitational motion and the vestibular system in humans  

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Full Text Available The visual system is poorly sensitive to arbitrary accelerations, but accurately detects the effects of gravity on a target motion. Here we review behavioral and neuroimaging data about the neural mechanisms for dealing with object motion and egomotion under gravity. The results from several experiments show that the visual estimates of a target motion under gravity depend on the combination of a prior of gravity effects with on-line visual signals on target position and velocity. These estimates are affected by vestibular inputs, and are encoded in a visual-vestibular network whose core regions lie within or around the Sylvian fissure, and are represented by the posterior insula/retroinsula/temporo-parietal junction. This network responds both to target motions coherent with gravity and to vestibular caloric stimulation in human fMRI studies. Transient inactivation of the temporo-parietal junction selectively disrupts the interception of targets accelerated by gravity.

FrancescoLacquaniti

2013-12-01

238

Normal pressure hydrocephalus after gamma knife radiosurgery for vestibular schwannoma  

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Full Text Available Vestibular schwannomas are not uncommon, and gamma knife radiosurgery is one of the treatment options for symptomatic tumors. Hydrocephalus is a complication of gamma knife treatment of vestibular schwannoma, though the mechanism of the development of hydrocephalus remains controversial. We present an unusual case of normal pressure hydrocephalus (NPH after gamma knife radiosurgery of a vestibular schwannoma in which the timeline of events strongly suggests that gamma knife played a contributory role in the development of the hydrocephalus. This is probably the first case of NPH post radiosurgery with normal cerebrospinal fluid protein. Communicating hydrocephalus should be treated with placement of shunt while non-communicating hydrocephalus can be treated with third ventriculostomy. Frequent monitoring and early intervention post radiosurgery is highly recommended to prevent irreversible cerebral damage.

Mohammed T

2010-01-01

239

Visual and proprioceptive interaction in patients with bilateral vestibular loss.  

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Following bilateral vestibular loss (BVL) patients gradually adapt to the loss of vestibular input and rely more on other sensory inputs. Here we examine changes in the way proprioceptive and visual inputs interact. We used functional magnetic resonance imaging (fMRI) to investigate visual responses in the context of varying levels of proprioceptive input in 12 BVL subjects and 15 normal controls. A novel metal-free vibrator was developed to allow vibrotactile neck proprioceptive input to be delivered in the MRI system. A high level (100 Hz) and low level (30 Hz) control stimulus was applied over the left splenius capitis; only the high frequency stimulus generates a significant proprioceptive stimulus. The neck stimulus was applied in combination with static and moving (optokinetic) visual stimuli, in a factorial fMRI experimental design. We found that high level neck proprioceptive input had more cortical effect on brain activity in the BVL patients. This included a reduction in visual motion responses during high levels of proprioceptive input and differential activation in the midline cerebellum. In early visual cortical areas, the effect of high proprioceptive input was present for both visual conditions but in lateral visual areas, including V5/MT, the effect was only seen in the context of visual motion stimulation. The finding of a cortical visuo-proprioceptive interaction in BVL patients is consistent with behavioural data indicating that, in BVL patients, neck afferents partly replace vestibular input during the CNS-mediated compensatory process. An fMRI cervico-visual interaction may thus substitute the known visuo-vestibular interaction reported in normal subject fMRI studies. The results provide evidence for a cortical mechanism of adaptation to vestibular failure, in the form of an enhanced proprioceptive influence on visual processing. The results may provide the basis for a cortical mechanism involved in proprioceptive substitution of vestibular function in BVL patients. PMID:25061564

Cutfield, Nicholas J; Scott, Gregory; Waldman, Adam D; Sharp, David J; Bronstein, Adolfo M

2014-01-01

240

Visual and proprioceptive interaction in patients with bilateral vestibular loss?  

Science.gov (United States)

Following bilateral vestibular loss (BVL) patients gradually adapt to the loss of vestibular input and rely more on other sensory inputs. Here we examine changes in the way proprioceptive and visual inputs interact. We used functional magnetic resonance imaging (fMRI) to investigate visual responses in the context of varying levels of proprioceptive input in 12 BVL subjects and 15 normal controls. A novel metal-free vibrator was developed to allow vibrotactile neck proprioceptive input to be delivered in the MRI system. A high level (100 Hz) and low level (30 Hz) control stimulus was applied over the left splenius capitis; only the high frequency stimulus generates a significant proprioceptive stimulus. The neck stimulus was applied in combination with static and moving (optokinetic) visual stimuli, in a factorial fMRI experimental design. We found that high level neck proprioceptive input had more cortical effect on brain activity in the BVL patients. This included a reduction in visual motion responses during high levels of proprioceptive input and differential activation in the midline cerebellum. In early visual cortical areas, the effect of high proprioceptive input was present for both visual conditions but in lateral visual areas, including V5/MT, the effect was only seen in the context of visual motion stimulation. The finding of a cortical visuo-proprioceptive interaction in BVL patients is consistent with behavioural data indicating that, in BVL patients, neck afferents partly replace vestibular input during the CNS-mediated compensatory process. An fMRI cervico-visual interaction may thus substitute the known visuo-vestibular interaction reported in normal subject fMRI studies. The results provide evidence for a cortical mechanism of adaptation to vestibular failure, in the form of an enhanced proprioceptive influence on visual processing. The results may provide the basis for a cortical mechanism involved in proprioceptive substitution of vestibular function in BVL patients. PMID:25061564

Cutfield, Nicholas J.; Scott, Gregory; Waldman, Adam D.; Sharp, David J.; Bronstein, Adolfo M.

2014-01-01

 
 
 
 
241

Cisplatin ototoxicity in the guinea pig: vestibular and cochlear damage.  

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The aim of the present study was to investigate both vestibular and cochlear cisplatin toxicity. Twelve albino guinea pigs were divided into an experimental (n=8) and a control saline group (n=4) and were treated with cisplatin at a daily dose of 2.5 mg/kg for 6 consecutive days. Vestibular dysfunction was evaluated by computing the gain of the vestibular ocular reflex (VOR) evoked by stimulation in the horizontal (HVOR) and vertical (VVOR) planes. Changes in cochlear function were characterised as compound action potential threshold shifts. After the functional testing, tympanic bullae were removed and processed for morphological examination of the sensorineural epithelium. The onset of vestibular functional impairment was observed on the third day, although the VOR gain decrease was not significant. The impairment of the vestibular function progressed until the sixth day becoming statistically significant particularly at VVOR mid frequencies of stimulation. At these frequencies both macula and crista ampullaris functions are involved. Concomitantly a progressive auditory threshold shift was observed at all stimulus frequencies. The decline of the auditory function was statistically significant from the third day of treatment and it was more evident at high frequencies. Morphological observations showed a massive loss of outer hair cells and a degeneration of the organ of Corti in the basal/middle turns and only a slight loss of hair cells of the cristae ampullares and maculae. In conclusion, functional and morphological data provide evidence that the toxic effect of cisplatin is more pronounced in the organ of Corti than in the vestibular epithelium. PMID:12948602

Sergi, Bruno; Ferraresi, Aldo; Troiani, Diana; Paludetti, Gaetano; Fetoni, Anna Rita

2003-08-01

242

Plasticity during Vestibular Compensation: The Role of Saccades  

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This paper is focused on one major aspect of compensation: the recent measures of saccadic responses to high acceleration head turns during human vestibular compensation and their possible implications for recovery after unilateral vestibular loss (UVL). New measurement techniques have provided additional insights into how patients recover after UVL and have given clues for vestibular rehabilitation. Prior to this it has not been possible to quantify the level of function of all the peripheral vestibular sense organs. Now it is. By using vestibular-evoked myogenic potentials to measure utricular and saccular function and by new video head impulse testing to measure semicircular canal function to natural values of head accelerations. With these new video procedures it is now possible to measure both slow phase eye velocity and also saccades during head movements with natural values of angular acceleration. The present evidence is that after UVL there is little or no restoration/compensation of slow phase eye velocity responses to natural head accelerations. It is doubtful as to whether the modest changes in slow phase eye velocity to small angular accelerations are functionally effective during compensation. On the other hand it is now clear that saccades can play a very important role in helping patients compensate and return to a normal lifestyle. Preliminary evidence suggests that different patterns of saccadic response may predict how well patients recover. Furthermore it may be possible to train patients to produce more effective saccadic patterns in the first days after their unilateral loss and possibly improve their compensation process. Some patients do learn new strategies, new behaviors, to conceal their inadequate vestibulo-ocular response but when those strategies are prevented from operating by using passive, unpredictable, high acceleration natural head movements, as in the head impulse test, the vestibular loss can be demonstrated. It is those very strategies which the tests exclude, which may be the cause of their successful compensation. PMID:22403569

MacDougall, Hamish Gavin; Curthoys, Ian S.

2011-01-01

243

Plasticity during vestibular compensation: the role of saccades  

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Full Text Available This paper is focussed on one major aspect of compensation: the recent behavioural findings concerning oculomotor responses in human vestibular compensation and their possible implications for recovery after unilateral vestibular loss (UVL. New measurement techniques have provided new insights into how patients recover after UVL and have given clues for vestibular rehabilitation. Prior to this it has not been possible to quantify the level of function of all the peripheral vestibular sense organs. Now it is. By using vestibular-evoked myogenic potentials to measure utricular and saccular function and by new video head impulse testing to measure semicircular canal function to natural values of head accelerations. With these new video procedures it is now possible to measure both slow phase eye velocity and also saccades during natural head movements. The present evidence is that there is little or no recovery of slow phase eye velocity responses to natural head accelerations. It is doubtful as to whether the modest changes in slow phase eye velocity to small angular accelerations are functionally effective during compensation. On the other hand it is now clear that saccades can play a very important role in helping patients compensate and return to a normal lifestyle. Preliminary evidence suggests that different patterns of saccadic response may predict how well patients recover. It may be possible to train patients to produce more effective saccadic patterns in the first days after their unilateral loss. Some patients do learn new strategies, new behaviours, to conceal their inadequate VOR but when those strategies are prevented from operating by using passive, unpredictable, high acceleration natural head movements, as in the head impulse test, their vestibular loss can be demonstrated. It is those very strategies which the tests exclude, which may be the cause of their successful compensation.

IanSCurthoys

2012-02-01

244

A model analysis of static stress in the vestibular membranes  

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Full Text Available Abstract Background The scheme of the core vestibular membranes, consisting of serially connected utricle, ampulla and semicircular canal, first appeared hundreds of millions of years ago in primitive fish and has remained largely unchanged during the subsequent course of evolution. The labyrinths of higher organisms build on this core structure, with the addition of the phylogenetically newer membrane structures, namely, saccule, lagena and cochlea. An analysis of static stress in these core vestibular membranes may contribute to a better understanding of the role of stress in the evolution of derivative membrane structures over the long term as well as the short-term membrane distortions seen in Meniere's disease. Methods A model of these core vestibular membranes is proposed in order to analyze the distribution of stress in the walls of the component chambers. The model uses basic geometrical elements of hollow cylinders and spheres to emulate the actual structures. These model elements lend themselves to a mathematical analysis of static stress in their membranes. Results Hoop stress, akin to the stress in hoops used to reinforce barrel walls, is found to be the predominant stress in the model membranes. The level of hoop stress depends not only on pressure but as well on a geometric stress factor that incorporates membrane shape, thickness and curvature. This result implies that hoop stress may be unevenly distributed in the membranes of the several vestibular chambers due to variations in these dimensional parameters. These results provide a theoretical framework for appraising hoop stress levels in any vestibular labyrinth whose dimensions are known. Conclusion Static hoop stress disparities are likely to exist in the vestibular membranes given their complex physical configurations. Such stress disparities may contribute to the development of membrane pathologies as seen in Meniere's Disease. They may also factor in the evolutionary development of other derivative membrane structures such as the saccule, the lagena, and the cochlea found in higher animals.

Pender Daniel J

2009-09-01

245

Vestibular Rehabilitation In Unilateral Peripheral Vestibulopathy: A Preliminary Report  

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Full Text Available Vestibular rehabilitation was indicated for patients with vestibulopathy. We evaluated the effect of home supervised vestibular rehabilitation and visual feedback posturography training fourteen patients in a controlled study. Patients were assessed before and after rehabilitation by the Dynamic gait index, the Dizziness handicap inventory, the Berg balance scale and by static posturography. Supervised home program group significantly improved in Berg balance scale, dizziness handicap inventory and movement velocity (p<0.05. Visual feedback posturography group improved significantly in dizziness handicap inventory, reaction time, movement velocity and maximum excursion (p<0.05. But there were not significant differences between home supervised and visual feedback posturography group after treatment.

Birgul DONMEZ

2008-06-01

246

Superior Semicircular Canal Dehiscence Syndrome without Vestibular Symptoms  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction Superior semicircular canal dehiscence syndrome is mainly characterized by vestibular symptoms induced by intense sound stimuli or pressure changes, which occur because of dehiscence of the bony layer covering the superior semicircular canal. Case Report Here, we report a case of t [...] he syndrome with pulsatile tinnitus and ear fullness, in the absence of vestibular symptoms. Discussion Signs and symptoms of the syndrome are rarely obvious, leading to the requirement for a minimum workup to rule out or make diagnosis more probable and thus avoid misconduct.

Emidio Oliveira, Teixeira; Marconi Teixeira, Fonseca.

2014-04-01

247

Superior Semicircular Canal Dehiscence Syndrome without Vestibular Symptoms  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction Superior semicircular canal dehiscence syndrome is mainly characterized by vestibular symptoms induced by intense sound stimuli or pressure changes, which occur because of dehiscence of the bony layer covering the superior semicircular canal. Case Report Here, we report a case of t [...] he syndrome with pulsatile tinnitus and ear fullness, in the absence of vestibular symptoms. Discussion Signs and symptoms of the syndrome are rarely obvious, leading to the requirement for a minimum workup to rule out or make diagnosis more probable and thus avoid misconduct.

Emidio Oliveira, Teixeira; Marconi Teixeira, Fonseca.

248

Volumetric Modulated Arc Radiotherapy for Vestibular Schwannomas  

International Nuclear Information System (INIS)

Purpose: To evaluate volumetric modulated arc radiotherapy (RapidArc [RA]), a novel approach allowing for rapid treatment delivery, for the treatment of vestibular schwannoma (VS). Methods and Materials: The RA plans were generated for a small (0.5 cm3), intermediate (2.8 cm3), and large (14.8 cm3) VS. The prescription dose was 12.5 Gy to the encompassing 80% isodose. The RA plans were compared with conventional radiosurgery plans using both a single dynamic conformal arc (1DCA) and five noncoplanar dynamic conformal arcs (5DCA). Conformity indices (CI) and dose-volume histograms of critical organs were compared. The RA plan for the medium-sized VS was measured in a phantom using Gafchromic EBT films and compared with calculated dose distributions. Results: The RA planning was completed within 30 min in all cases, and calculated treatment delivery time (after patient setup) was 5 min vs. 20 min for 5DCA. A superior CI was achieved with RA, with a substantial decrease in low-dose irradiation of the normal brain achieved relative to 5DCA plans. Maximum doses to critical organs were similar for RA and 5DCA but were higher for 1DCA. Film measurements showed the differences between calculated and measured doses to be smaller than 1.5% in the high-dose area and smaller than 3% in the low-dose area. Conclusion: The RA plans consistently achieved a higher CI and decrease in areas of low-dose irradiation. This, together with shorter treatment dn. This, together with shorter treatment delivery times, has led to RA replacing our conventional five-arc radiosurgery technique for VS.

249

Polyamines in the lateral vestibular nuclei of the squirrel monkey and their potential role in vestibular compensation  

Science.gov (United States)

Polyamine synthesis increases in response to injurious stimuli including axotomy and denervation. Reduced eye nystagmus and head-deviation have been observed in unilateral labyrinthectomized (UL) guinea pigs treated with an inhibitor of polyamine synthesis, alpha-difluoromethylornithine (DFMO). We quantified polyamines in the lateral vestibular nuclei (LVN) of control and UL squirrel monkeys during the phase of vestibular compensation (VC) and performed an experiment to determine if DFMO reduces nystagmus previously observed in the guinea pig. Polyamines were detected in the LVN of control and UL squirrel monkeys. Putrescine and spermidine increased in the ipsilateral LVN 3 days after UL with no change in the contralateral LVN. No left-right differences were noted in the 5-day post-UL monkey. DFMO reduced nystagmus in a UL squirrel monkey. These findings suggest that polyamines are important in vestibular function and may contribute to nystagmus observed in VC.

Henley, C.; Igarashi, M.

1993-01-01

250

Use of the Vestibular Disorders Activities of Daily Living Scale to describe functional limitations in patients with vestibular disorders.  

Science.gov (United States)

The Vestibular Disorders Activities of Daily Living Scale (VADL) is one of several self-rated scales in the literature that may be useful for determining level of functional limitation or disability in people with vestibular disorders. The VADL was designed by an occupational therapist for use in treatment planning during vestibular rehabilitation. Unlike many other scales the VADL is specifically focused on essential functional skills and important mobility and instrumental skills. This paper reviews the findings about the VADL, including the original research about its development and more recent papers using it. The scale is most useful for assessing the patient's perception about independence in personal, self care and basic mobility skills. It provides an outline for discussing instrumental activities of daily living. PMID:24594498

Cohen, Helen S

2014-01-01

251

Can an electro-tactile vestibular substitution system improve balance in patients with unilateral vestibular loss under altered somatosensory conditions from the foot and ankle?  

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This pilot study aimed at assessing the feasibility and the effectiveness of an electro-tactile vestibular substitution system (EVSS) in patients with unilateral vestibular loss under normal and altered somatosensory conditions from the foot and ankle. Four unilateral vestibular-defective patients voluntarily participated in the experiment. They were asked to stand upright as still as possible with their eyes closed in two Normal and Altered foot and ankle sensory conditions. These conditions...

Vuillerme, N.; Hlavackova, P.; Franco, C.; Diot, B.; Demongeot, J.; Payan, Yohan

2011-01-01

252

The Role of Cervical and Ocular Vestibular Evoked Myogenic Potentials in the Assessment of Patients with Vestibular Schwannomas  

Science.gov (United States)

Objectives To investigate the clinical utility of VEMPs in patients suffering from unilateral vestibular schwannoma (VS) and to determine the optimal stimulation parameter (air conducted sound, bone conducted vibration) for evaluating the function of the vestibular nerve. Methods Data were obtained in 63 patients with non-operated VS, and 20 patients operated on VS. Vestibular function was assessed by caloric, cervical and ocular VEMP testing. 37/63 patients with conclusive ACS ocular VEMPs responses were studied separately. Results In the 63 non-operated VS patients, cVEMPs were abnormal in 65.1% of patients in response to AC STB and in 49.2% of patients to AC clicks. In the 37/63 patients with positive responses from the unaffected side, oVEMPs were abnormal in 75.7% of patients with ACS, in 67.6% with AFz and in 56.8% with mastoid BCV stimulation. In 16% of the patients, VEMPs were the only abnormal test (normal caloric and normal hearing). Among the 26 patients who did not show oVEMP responses on either side with ACS, oVEMPs responses could be obtained with AFz (50%) and with mastoid stimulation (89%). Conclusions The VEMP test demonstrated significant clinical value as it yielded the only abnormal test results in some patients suffering from a unilateral vestibular schwannoma. For oVEMPs, we suggest that ACS stimulation should be the initial test. In patients who responded to ACS and who had normal responses, BCV was not required. In patients with abnormal responses on the affected side using ACS, BCV at AFz should be used to confirm abnormal function of the superior vestibular nerve. In patients who exhibited no responses on either side to ACS, BCV was the only approach allowing assessment of the function of the superior vestibular nerve. We favor using AFz stimulation first because it is easier to perform in clinical practice than mastoid stimulation. PMID:25137289

Chiarovano, Elodie; Darlington, Cynthia; Vidal, Pierre-Paul; Lamas, Georges; de Waele, Catherine

2014-01-01

253

[A electromyographic study of the vestibular reflexes. A clinical experimental study on human beings (author's transl)].  

Science.gov (United States)

It is reported about myography on testpersons with normal vestibular function as well as on patients after operativ dissection of the VIII. nerve, neuropathia nerv. vest. and M. Menière. On the base of these findings it is supposed that myography proofes to be a useful help in the judgement of the specific influence of the vestibular organs on the motoric system. The myographic changes of the muscular activity after caloric stimulation give exact information about the entire vestibular system and especially about the vestibular-spinal-pathways. The best way of testing the vestibular activity is performed on musculars with symmetric, simultaneous and reziproke intented innervation, f.i. on the sternocleidomastoidei muscels in slight deflected position of the head. Most significant for the vestibular influence are an increase of the base-activity and the appearance of groups of potentials which are related to the vestibular stimulus in time and intensity. PMID:169443

Emami-Nouri, M

1975-06-01

254

Factors relating to depressive symptoms among elderly people with chronic vestibular dysfunction / Fatores relacionados aos sintomas depressivos de idosos com disfunção vestibular crônica  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese OBJETIVO: Identificar os fatores relacionados aos sintomas depressivos de idosos com disfunção vestibular crônica. MÉTODO: Estudo transversal, em que 120 idosos com disfunção vestibular crônica submeteram-se ao questionário Geriatric Depression Scale. Realizou-se análise de regressão linear multivar [...] iada (p Abstract in english OBJECTIVE: To identify factors relating to depressive symptoms among elderly people with chronic vestibular dysfunction. METHOD: This was a cross-sectional study in which 120 elderly people with chronic vestibular dysfunction answered the Geriatric Depression Scale questionnaire. Multivariate linear [...] regression analysis was performed (p

Juliana Maria, Gazzola; Mayra Cristina, Aratani; Flávia, Doná; Camila, Macedo; Márcia Maiumi, Fukujima; Maurício Malavasi, Ganança; Fernando Freitas, Ganança.

2009-06-01

255

Configuração das pregas vestibulares em laringes de pacientes com nódulo vocal / Vestibular folds configuration in vocal nodule  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O nódulo vocal está entre as laringopatias mais comuns que resultam em alterações na função vocal. O mecanismo da produção da fala é complexo e exige interação de diversos sistemas do organismo humano. A importância das pregas vocais na fisiologia e na formação da fonte sonora glótica é evidente; co [...] ntudo, quanto à participação das pregas vestibulares neste processo, ainda não existe consenso entre os estudiosos da área. OBJETIVO: Verificar se existe diferença na conformação das pregas vestibulares entre dois grupos de indivíduos do sexo feminino, sendo um composto por pacientes com diagnóstico de nódulo vocal e outro por pacientes sem alteração da voz e sem lesão em pregas vocais. FORMA DE ESTUDO: clínico com coorte transversal MATERIAL E MÉTODO: Foram analisadas 96 imagens de laringes, de indivíduos do sexo feminino, sendo 48 sem queixa vocal e 48 com diagnóstico de nódulo vocal. Foram medidos os ângulos formados nas pregas vestibulares durante a fonação, dos lados direito e esquerdo, bem como feita classificação das mesmas quanto à forma (côncava, linear ou convexa). RESULTADOS: Das 96 pregas vestibulares analisadas em cada grupo, a forma côncava foi predominante, seguida da linear e da convexa. No grupo controle, apenas uma das pregas estudadas tinha a conformação convexa, 27 conformação linear e 68 eram côncavas, enquanto no grupo nódulo vocal os resultados foram 8 convexas, 15 lineares e 73 côncavas. Estas diferenças não apresentaram significância, bem como as diferenças nos ângulos, cujas médias foram bastante semelhantes. CONCLUSÃO: As pregas vestibulares no sexo feminino se comportam da mesma maneira tanto nas pacientes com nódulo vocal quanto nas mulheres sem queixa vocal. Abstract in english Vocal nodules are among the most common laryngopathies that cause vocal functional disorders. The voice production mechanism is complex and demand interaction of different systems of the human body. The physiological role of the vocal folds as the glottic sound source is evident, however, there is n [...] o consensus regarding the vestibular folds' participation/influence in phonation. AIM: To verify if there is difference in the bidimensional configuration of the vestibular folds between two distinct groups of women, one with the diagnosis of vocal nodules and the other without vocal complaints and vocal fold lesions. STUDY DESIGN: clinical with transversal cohort. MATERIAL AND METHOD: Ninety-six laryngeal images were evaluated, 48 from individuals without vocal complaints and 48 from patients with the diagnosis of vocal nodules. Angles were obtained and bilaterally measured in single frames of the vestibular folds during sustained phonation and those structures were morphologically classified as concave, linear or convex. RESULTS: Among the 96 vestibular folds evaluated in each group, there was predominance of the concave form, followed by the linear and the convex ones. In the control group, there was a single convex vestibular fold, 27 were linear and 68 were concave folds. In the group of vocal nodules, 8 were convex, 15 were linear and 73 were concave folds. However, the differences among groups were not statistically significant as well as those among the angles, whose average measures were proven quite similar. CONCLUSION: In the female gender, the vestibular folds presented similar behavior regarding the morphology in both patients with vocal nodules and women without vocal complaints.

Juliane, Tuma; Osíris Oliveira, Camponês do Brasil; Paulo Augusto de Lima, Pontes; Reinaldo Kasuo, Yasaki.

2005-10-01

256

Configuração das pregas vestibulares em laringes de pacientes com nódulo vocal Vestibular folds configuration in vocal nodule  

Directory of Open Access Journals (Sweden)

Full Text Available O nódulo vocal está entre as laringopatias mais comuns que resultam em alterações na função vocal. O mecanismo da produção da fala é complexo e exige interação de diversos sistemas do organismo humano. A importância das pregas vocais na fisiologia e na formação da fonte sonora glótica é evidente; contudo, quanto à participação das pregas vestibulares neste processo, ainda não existe consenso entre os estudiosos da área. OBJETIVO: Verificar se existe diferença na conformação das pregas vestibulares entre dois grupos de indivíduos do sexo feminino, sendo um composto por pacientes com diagnóstico de nódulo vocal e outro por pacientes sem alteração da voz e sem lesão em pregas vocais. FORMA DE ESTUDO: clínico com coorte transversal MATERIAL E MÉTODO: Foram analisadas 96 imagens de laringes, de indivíduos do sexo feminino, sendo 48 sem queixa vocal e 48 com diagnóstico de nódulo vocal. Foram medidos os ângulos formados nas pregas vestibulares durante a fonação, dos lados direito e esquerdo, bem como feita classificação das mesmas quanto à forma (côncava, linear ou convexa. RESULTADOS: Das 96 pregas vestibulares analisadas em cada grupo, a forma côncava foi predominante, seguida da linear e da convexa. No grupo controle, apenas uma das pregas estudadas tinha a conformação convexa, 27 conformação linear e 68 eram côncavas, enquanto no grupo nódulo vocal os resultados foram 8 convexas, 15 lineares e 73 côncavas. Estas diferenças não apresentaram significância, bem como as diferenças nos ângulos, cujas médias foram bastante semelhantes. CONCLUSÃO: As pregas vestibulares no sexo feminino se comportam da mesma maneira tanto nas pacientes com nódulo vocal quanto nas mulheres sem queixa vocal.Vocal nodules are among the most common laryngopathies that cause vocal functional disorders. The voice production mechanism is complex and demand interaction of different systems of the human body. The physiological role of the vocal folds as the glottic sound source is evident, however, there is no consensus regarding the vestibular folds' participation/influence in phonation. AIM: To verify if there is difference in the bidimensional configuration of the vestibular folds between two distinct groups of women, one with the diagnosis of vocal nodules and the other without vocal complaints and vocal fold lesions. STUDY DESIGN: clinical with transversal cohort. MATERIAL AND METHOD: Ninety-six laryngeal images were evaluated, 48 from individuals without vocal complaints and 48 from patients with the diagnosis of vocal nodules. Angles were obtained and bilaterally measured in single frames of the vestibular folds during sustained phonation and those structures were morphologically classified as concave, linear or convex. RESULTS: Among the 96 vestibular folds evaluated in each group, there was predominance of the concave form, followed by the linear and the convex ones. In the control group, there was a single convex vestibular fold, 27 were linear and 68 were concave folds. In the group of vocal nodules, 8 were convex, 15 were linear and 73 were concave folds. However, the differences among groups were not statistically significant as well as those among the angles, whose average measures were proven quite similar. CONCLUSION: In the female gender, the vestibular folds presented similar behavior regarding the morphology in both patients with vocal nodules and women without vocal complaints.

Juliane Tuma

2005-10-01

257

Posturografia com estímulos de realidade virtual nas diferentes disfunções vestibulares / Posturography with virtual reality stimuli in different vestibular dysfunctions  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: Avaliar o equilíbrio corporal e quantificar possíveis alterações na posturografia estática do Balance Rehabilitation Unit (BRU TM) em pacientes com disfunção vestibular. MÉTODOS: Estudo retrospectivo, com prontuários de 100 pacientes com topodiagnóstico de disfunção vestibular periférica o [...] u central e 100 indivíduos hígidos compondo o Grupo Controle, de ambos os gêneros, entre 7 a 86 anos. Para a posturografia foi utilizado o equipamento Balance Rehabilitation Unit (BRU TM), da Medicaa®. Foram analisados os parâmetros limite de estabilidade, área de elipse e velocidade de oscilação em dez condições sensoriais. RESULTADOS: A média dos valores do limite de estabilidade, da área de elipse e da velocidade de oscilação do Grupo Experimental foi significativa em relação ao Grupo Controle em todas as condições. A média dos parâmetros do gênero feminino do Grupo Experimental foi significativa em relação ao do Grupo Controle em todas as condições avaliadas. Os pacientes com disfunção vestibular central obtiveram maiores valores que os pacientes com disfunção vestibular periférica nas variáveis área de elipse e velocidade de oscilação, porém menor valor da área do limite de estabilidade. CONCLUSÃO: A posturografia com estímulos de realidade virtual foi um método de avaliação eficaz para detectar alterações relacionadas às variáveis limite de estabilidade, área de elipse e velocidade de oscilação, uma vez que o Grupo Controle obteve melhor desempenho, tanto entre os grupos quanto entre os gêneros. Entre as disfunções vestibulares, os indivíduos com acometimento periférico obtiveram melhor desempenho do que os indivíduos com disfunção vestibular central em todas as variáveis analisadas na posturografia. Abstract in english PURPOSE: To assess body balance and to quantify possible alterations over the static posturography of the Balance Rehabilitation Unit (BRU TM) in patients with vestibular dysfunction. METHODS: Retrospective study, with files of 100 patients with topographic diagnosis of peripheral or central vestibu [...] lar dysfunction and 100 healthy individuals that composed the control group, of both genders, with ages varying between 7 and 86 years. For the posturography, the Balance Rehabilitation Unit (BRU TM), of Medicaa® was used. The following parameters were analyzed: stability limits, elliptical area, and speed of oscillation in ten sensory conditions. RESULTS: Mean values ??of the stability limit, the elliptical area and the speed of oscillation in the experimental group was significant when compared to the control group in all conditions. The mean parameters of the female experimental group were significant when compared to the control group in all conditions. Patients with central vestibular dysfunction obtained higher values than patients with peripheral vestibular dysfunction in the variables elliptical area and speed of oscillation, however with lower value of the area of the stability limit. CONCLUSION: Posturography with virtual reality stimuli was an effective assessment method for detecting alterations related to the variables stability limits, elliptical area, and speed of oscillation, since the control group performed better, both between groups and between genders. Among the vestibular dysfunctions, individuals with peripheral condition performed better than those with central vestibular dysfunction in all the variables analyzed on posturography.

Marcelo Eiji Inoue, Yamamoto; Cristina Freitas, Ganança.

2012-03-01

258

Posturografia com estímulos de realidade virtual nas diferentes disfunções vestibulares / Posturography with virtual reality stimuli in different vestibular dysfunctions  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: Avaliar o equilíbrio corporal e quantificar possíveis alterações na posturografia estática do Balance Rehabilitation Unit (BRU TM) em pacientes com disfunção vestibular. MÉTODOS: Estudo retrospectivo, com prontuários de 100 pacientes com topodiagnóstico de disfunção vestibular periférica o [...] u central e 100 indivíduos hígidos compondo o Grupo Controle, de ambos os gêneros, entre 7 a 86 anos. Para a posturografia foi utilizado o equipamento Balance Rehabilitation Unit (BRU TM), da Medicaa®. Foram analisados os parâmetros limite de estabilidade, área de elipse e velocidade de oscilação em dez condições sensoriais. RESULTADOS: A média dos valores do limite de estabilidade, da área de elipse e da velocidade de oscilação do Grupo Experimental foi significativa em relação ao Grupo Controle em todas as condições. A média dos parâmetros do gênero feminino do Grupo Experimental foi significativa em relação ao do Grupo Controle em todas as condições avaliadas. Os pacientes com disfunção vestibular central obtiveram maiores valores que os pacientes com disfunção vestibular periférica nas variáveis área de elipse e velocidade de oscilação, porém menor valor da área do limite de estabilidade. CONCLUSÃO: A posturografia com estímulos de realidade virtual foi um método de avaliação eficaz para detectar alterações relacionadas às variáveis limite de estabilidade, área de elipse e velocidade de oscilação, uma vez que o Grupo Controle obteve melhor desempenho, tanto entre os grupos quanto entre os gêneros. Entre as disfunções vestibulares, os indivíduos com acometimento periférico obtiveram melhor desempenho do que os indivíduos com disfunção vestibular central em todas as variáveis analisadas na posturografia. Abstract in english PURPOSE: To assess body balance and to quantify possible alterations over the static posturography of the Balance Rehabilitation Unit (BRU TM) in patients with vestibular dysfunction. METHODS: Retrospective study, with files of 100 patients with topographic diagnosis of peripheral or central vestibu [...] lar dysfunction and 100 healthy individuals that composed the control group, of both genders, with ages varying between 7 and 86 years. For the posturography, the Balance Rehabilitation Unit (BRU TM), of Medicaa® was used. The following parameters were analyzed: stability limits, elliptical area, and speed of oscillation in ten sensory conditions. RESULTS: Mean values ??of the stability limit, the elliptical area and the speed of oscillation in the experimental group was significant when compared to the control group in all conditions. The mean parameters of the female experimental group were significant when compared to the control group in all conditions. Patients with central vestibular dysfunction obtained higher values than patients with peripheral vestibular dysfunction in the variables elliptical area and speed of oscillation, however with lower value of the area of the stability limit. CONCLUSION: Posturography with virtual reality stimuli was an effective assessment method for detecting alterations related to the variables stability limits, elliptical area, and speed of oscillation, since the control group performed better, both between groups and between genders. Among the vestibular dysfunctions, individuals with peripheral condition performed better than those with central vestibular dysfunction in all the variables analyzed on posturography.

Marcelo Eiji Inoue, Yamamoto; Cristina Freitas, Ganança.

259

Identification of neural networks that contribute to motion sickness through principal components analysis of fos labeling induced by galvanic vestibular stimulation.  

Science.gov (United States)

Motion sickness is a complex condition that includes both overt signs (e.g., vomiting) and more covert symptoms (e.g., anxiety and foreboding). The neural pathways that mediate these signs and symptoms are yet to identified. This study mapped the distribution of c-fos protein (Fos)-like immunoreactivity elicited during a galvanic vestibular stimulation paradigm that is known to induce motion sickness in felines. A principal components analysis was used to identify networks of neurons activated during this stimulus paradigm from functional correlations between Fos labeling in different nuclei. This analysis identified five principal components (neural networks) that accounted for greater than 95% of the variance in Fos labeling. Two of the components were correlated with the severity of motion sickness symptoms, and likely participated in generating the overt signs of the condition. One of these networks included neurons in locus coeruleus, medial, inferior and lateral vestibular nuclei, lateral nucleus tractus solitarius, medial parabrachial nucleus and periaqueductal gray. The second included neurons in the superior vestibular nucleus, precerebellar nuclei, periaqueductal gray, and parabrachial nuclei, with weaker associations of raphe nuclei. Three additional components (networks) were also identified that were not correlated with the severity of motion sickness symptoms. These networks likely mediated the covert aspects of motion sickness, such as affective components. The identification of five statistically independent component networks associated with the development of motion sickness provides an opportunity to consider, in network activation dimensions, the complex progression of signs and symptoms that are precipitated in provocative environments. Similar methodology can be used to parse the neural networks that mediate other complex responses to environmental stimuli. PMID:24466215

Balaban, Carey D; Ogburn, Sarah W; Warshafsky, Susan G; Ahmed, Abdul; Yates, Bill J

2014-01-01

260

Effects of Tactile and Audio Cues on Reducing Vestibular Illusions.  

Science.gov (United States)

The effect of multisensory cues (3-D, audio, tactile belt) to overcome a vestibular illusion in a rotating Barany Chair was investigated. Seated subjects were rotated about their spinal axis (Z axis) from a standing stop to a predetermined velocity. The a...

D. Bowden, L. Guzy, W. Albery

2006-01-01

 
 
 
 
261

Doença vestibular periférica decorrente de osteoartropatia temporoioídea em um eqüino  

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Full Text Available Um eqüino com 22 anos de idade apresentou síndrome vestibular periférica associada à paralisia de nervo facial esquerdo devido à osteoartropatia temporoioídea. O exame endoscópico das bolsas guturais mostrou alteração de contorno da bula timpânica esquerda e aumento de volume da extremidade proximal do osso estiloióide do mesmo lado.

Borges Alexandre Secorun

2003-01-01

262

Complex vestibular macular anatomical relationships need a synthetic approach  

Science.gov (United States)

Mammalian vestibular maculae are anatomically organized for complex parallel processing of linear acceleration information. Anatomical findings in rat maculae are provided in order to underscore this complexity, which is little understood functionally. This report emphasizes that a synthetic approach is critical to understanding how maculae function and the kind of information they conduct to the brain.

Ross, M. D.

2001-01-01

263

Vestibular benefits to task savings in motor adaptation.  

Science.gov (United States)

In everyday life, we seamlessly adapt our movements and consolidate them to multiple behavioral contexts. This natural flexibility seems to be contingent on the presence of movement-related sensorimotor cues and cannot be reproduced when static visual or haptic cues are given to signify different behavioral contexts. So far, only sensorimotor cues that dissociate the sensorimotor plans prior to force field exposure have been successful in learning two opposing perturbations. Here we show that vestibular cues, which are only available during the perturbation, improve the formation and recall of multiple control strategies. We exposed subjects to inertial forces by accelerating them laterally on a vestibular platform. The coupling between reaching movement (forward-backward) and acceleration direction (leftward-rightward) switched every 160 trials, resulting in two opposite force environments. When exposed for a second time to the same environment, with the opposite environment in between, subjects showed retention resulting in an ?3 times faster adaptation rate compared with the first exposure. Our results suggest that vestibular cues provide contextual information throughout the reach, which is used to facilitate independent learning and recall of multiple motor memories. Vestibular cues provide feedback about the underlying cause of reach errors, thereby disambiguating the various task environments and reducing interference of motor memories. PMID:23785131

Sarwary, A M E; Selen, L P J; Medendorp, W P

2013-09-01

264

La estimación visual de lo que está vertical en alteraciones vestibulares / The subjective visual vertical in vestibular disease  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish Objetivo. Identificar y comparar la precisión de la estimación visual de lo que está vertical, con y sin inclinación tronco-cefálica en el plano frontal (30°), en pacientes con enfermedad vestibular periférica o central. Métodos. Participaron 38 pacientes con enfermedad vestibular, periférica en 23 [...] y central en 15, además de 40 sujetos sin enfermedad vestibular. Se les instruyó a colocar en posición vertical una barra motorizada de 20 cm, manipulada por control remoto, mientras se encontraban sentados a 30 cm de una pantalla, sin guías visuales. Después de 10 determinaciones con el tronco y la cabeza erguidos y 10 determinación con inclinación tronco-cefálica de 30° a cada lado, se calculó el promedio del error de las estimaciones efectuadas en cada postura. Resultados. En sujetos sin enfermedad vestibular el error de la estimación en cualquier posición fue siempre menor a 2°. En posición erguida, el mayor error en la estimación se observó en pacientes con enfermedad periférica con nistagmus espontáneo. En todos los pacientes el error aumentó significativamente con inclinación tronco-cefálica (ANOVA, p Abstract in english Objective. To assess and compare the accuracy to perceive visual verticality, with and without trunk-head tilt in the frontal plane (30°), in patients with peripheral or central vestibular disease. Methods. Thirty eight patients accepted to participate, 23 with peripheral disease and 15 with central [...] disease. We also evaluated 40 healthy subjects. Subjects were seated facing a screen with an anchored motorized bar (20 cm). They were asked to bring the line to vertical, using a joystick, 10 times while seated upright and 10 times while tilted 30° to each side. An average of the distance from true vertical was calculated to determine the tilt of the visual vertical on each posture. Results. Always, estimations made by healthy subjects were

Catalina, Aranda-Moreno; Kathrine, Jáuregui -Renaud.

265

La estimación visual de lo que está vertical en alteraciones vestibulares / The subjective visual vertical in vestibular disease  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish Objetivo. Identificar y comparar la precisión de la estimación visual de lo que está vertical, con y sin inclinación tronco-cefálica en el plano frontal (30°), en pacientes con enfermedad vestibular periférica o central. Métodos. Participaron 38 pacientes con enfermedad vestibular, periférica en 23 [...] y central en 15, además de 40 sujetos sin enfermedad vestibular. Se les instruyó a colocar en posición vertical una barra motorizada de 20 cm, manipulada por control remoto, mientras se encontraban sentados a 30 cm de una pantalla, sin guías visuales. Después de 10 determinaciones con el tronco y la cabeza erguidos y 10 determinación con inclinación tronco-cefálica de 30° a cada lado, se calculó el promedio del error de las estimaciones efectuadas en cada postura. Resultados. En sujetos sin enfermedad vestibular el error de la estimación en cualquier posición fue siempre menor a 2°. En posición erguida, el mayor error en la estimación se observó en pacientes con enfermedad periférica con nistagmus espontáneo. En todos los pacientes el error aumentó significativamente con inclinación tronco-cefálica (ANOVA, p Abstract in english Objective. To assess and compare the accuracy to perceive visual verticality, with and without trunk-head tilt in the frontal plane (30°), in patients with peripheral or central vestibular disease. Methods. Thirty eight patients accepted to participate, 23 with peripheral disease and 15 with central [...] disease. We also evaluated 40 healthy subjects. Subjects were seated facing a screen with an anchored motorized bar (20 cm). They were asked to bring the line to vertical, using a joystick, 10 times while seated upright and 10 times while tilted 30° to each side. An average of the distance from true vertical was calculated to determine the tilt of the visual vertical on each posture. Results. Always, estimations made by healthy subjects were

Catalina, Aranda-Moreno; Kathrine, Jáuregui -Renaud.

2005-02-01

266

Schwanoma vestibular como causa de surdez súbita / Vestibular schwannoma presenting as sudden hearing loss  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A Surdez Súbita (SS) é um sintoma causado por mais de 60 doenças diferentes, dentre elas, o Schwanoma Vestibular (SV). Shaia & Sheehy (1976) apresentaram uma incidência de 1% de SV em 1220 casos de SS. Não há características específicas para o diagnóstico do SV, sendo a ressonância magnética (RM) o [...] exame de escolha. OBJETIVO: Verificar a real incidência de SV em casuísticas de SS com a realização de RM. FORMA DE ESTUDO: Coorte transversal. MATERIAL E MÉTODO: Estudo prospectivo com a realização de RM com contraste de gadolínio em todos os pacientes com SS do serviço de urgência em Otorrinolaringologia do Hospital São Paulo no período de abril de 2001 a maio de 2003. RESULTADOS: Foram realizados exames de RM em 49 pacientes que apresentaram SS, sendo diagnosticados 3 (6,1%) casos de SV. CONCLUSÃO: A incidência real de SV em casuísticas de SS pode ser maior do que o classicamente descrito na literatura, devido ao subdiagnóstico pela não-utilização da RM de rotina nestes casos. Abstract in english The sudden Hearing Loss (SHL) is a symptom caused by more than 60 different diseases, including Vestibular Schwannoma (VS). Shaia & Sheehy (1976) presented a study with 1,220 cases of SHL reporting 1% incidence of VS. There is no specific characteristic for the diagnosis of VS and Magnetic Resonance [...] Imaging (MRI) is the gold standard exam to diagnose such disease. AIM: To determine the real incidence of VS presenting as SHL performing MRI in all patients with SHL. STUDY DESIGN: Transversal cohort. MATERIL AND METHOD: Prospective study in which MRI with gadolinium was performed in all patients with SHL in the Emergency Service of Sao Paulo Hospital from April 2001 through May 2003. RESULTS: MRI was performed in 49 patients with symptoms of SHL, with three cases (6.1%) of VS found. CONCLUSION: The real incidence of VS presenting as SHL may be greater than that mentioned in conventional reports probably because MRI had not been performed in all patients with SHL.

Eduardo M., Kosugi; Rodrigo P., Tangerina; Gabriel C., Dib; Hugo V. L., Ramos; Norma O., Penido.

2004-12-01

267

Developmental and Age-related Changes in Morphometry and Cellular Density of the Vestibular Ganglion in the Chick  

Directory of Open Access Journals (Sweden)

Full Text Available Vestibular ganglia at different stages of development in the chick and that of the adult were fixed in formal-saline. Serial sections were taken and stained by cresyl fast violet to analyse the results. Cells were categorised and counted. Ganglionic volume is the greatest on E18 during the whole ontogeny even though its rostrocaudal length is the greatest in the adult. This is quite different from that observed in other ganglia studied where the ganglionic volume is the greatest in the adult situation. The increased size of the ganglion on E18 might be related to the increased size of the cells, increased size of the neuropil (network of neuronal processes and neuroglia and to the effects of tissue reactions resulting from the toxic substances of the dead cells. The loss of cells in the adult in comparison to that observed on the day of hatching might indicate a functional reduction as a result of ageing process. The fluctuation in the number of cells during development might be considered as a normal process for the purpose of re-arrangement for better organisation in order to perform an efficient function. The cell-loss has essentially ended around E15 by the time the ganglion begins to show its greatest expansion so as to reach its maximum size on E18. The appearance of a few light cells in the vestibular ganglion on E6 might indirectly indicate the beginning of an early establishment of a functional connection. This might possibly mean that an early development of functional organisation of the vestibular ganglion is an important factor for the proper development of other organs and systems during embryonic development. The appearance of an increased number of tiny cells in the adult ganglion is peculiar from that observed in other ganglia studied; possibly these tiny cells, by their growth, maturation and establishment of functional connections, replace those inactive (or dead cells, during ageing process. Possibly, continuation of an efficient vestibular function is important for the normal behaviour of the animal.

A.G. Pillay

1999-01-01

268

Simulation studies of vestibular macular afferent-discharge patterns using a new, quasi-3-D finite volume method  

Science.gov (United States)

A quasi-three-dimensional finite-volume numerical simulator was developed to study passive voltage spread in vestibular macular afferents. The method, borrowed from computational fluid dynamics, discretizes events transpiring in small volumes over time. The afferent simulated had three calyces with processes. The number of processes and synapses, and direction and timing of synapse activation, were varied. Simultaneous synapse activation resulted in shortest latency, while directional activation (proximal to distal and distal to proximal) yielded most regular discharges. Color-coded visualizations showed that the simulator discretized events and demonstrated that discharge produced a distal spread of voltage from the spike initiator into the ending. The simulations indicate that directional input, morphology, and timing of synapse activation can affect discharge properties, as must also distal spread of voltage from the spike initiator. The finite volume method has generality and can be applied to more complex neurons to explore discrete synaptic effects in four dimensions.

Ross, M. D.; Linton, S. W.; Parnas, B. R.

2000-01-01

269

Galvanic vestibular stimulator for fMRI studies  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english INTRODUCTION: Areas of the brain that are associated with the vestibular system can be activated using galvanic vestibular stimulation. These areas can be studied through a combination of galvanic vestibular stimulation with functional magnetic resonance imaging (fMRI). In order to provide an approp [...] riate sequence of galvanic stimulation synchronous with the MRI pulse sequence, a specific electronic device that was built and assessed is presented. METHODS: The electronic project of the GVS is divided in analog and digital circuits. The analog circuits are mounted in an aluminum case, supplied by sealed batteries, and goes inside the MRI room near to the feet of the subject. The digital circuits are placed in the MRI control room. Those circuits communicate through each other by an optical fiber. Tests to verify the GVS-MRI compatibility were conducted. Silicone (in-house) and Ag/AgCl (commercial) electrodes were evaluated for maximum balance and minimal pain sensations. fMRI experiments were conducted in eight human volunteers. RESULTS: GVS-MRI compatibility experiments demonstrate that the GVS did not interfere with the MRI scanner functionality and vice versa. The circular silicone electrode was considered the most suitable to apply the galvanic vestibular stimulation. The 1 Hz stimulation sinusoid frequency produced the biggest balance and the less pain sensations when compared to 2 Hz. The GVS was capable of eliciting activation in the precentral and postcentral gyri, in the central sulcus, in the supplementary motor area, in the middle and inferior frontal gyri, in the inferior parietal lobule, in the insula, in the superior temporal gyrus, in the middle cingulate cortex, and in the cerebellum. CONCLUSION: This study shows the development and description of a neurovestibular stimulator that can be safely used inside the MRI scanner room without interfering on its operation and vice versa. The developed GVS could successfully activate the major areas involved with multimodal functions of the vestibular system, demonstrating its validity as a stimulator for neurovestibular research. To the best of our knowledge, this is the first work that shows the development and the construction of a galvanic vestibular stimulator that could be safely used inside the MRI room.

Hellen Mathei, Della-Justina; Tiago, Manczak; Anderson Marcelo, Winkler; Dráulio Barros de, Araújo; Mauren Abreu de, Souza; Edson, Amaro Junior; Humberto Remigio, Gamba.

2014-03-01

270

Galvanic vestibular stimulator for fMRI studies  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english INTRODUCTION: Areas of the brain that are associated with the vestibular system can be activated using galvanic vestibular stimulation. These areas can be studied through a combination of galvanic vestibular stimulation with functional magnetic resonance imaging (fMRI). In order to provide an approp [...] riate sequence of galvanic stimulation synchronous with the MRI pulse sequence, a specific electronic device that was built and assessed is presented. METHODS: The electronic project of the GVS is divided in analog and digital circuits. The analog circuits are mounted in an aluminum case, supplied by sealed batteries, and goes inside the MRI room near to the feet of the subject. The digital circuits are placed in the MRI control room. Those circuits communicate through each other by an optical fiber. Tests to verify the GVS-MRI compatibility were conducted. Silicone (in-house) and Ag/AgCl (commercial) electrodes were evaluated for maximum balance and minimal pain sensations. fMRI experiments were conducted in eight human volunteers. RESULTS: GVS-MRI compatibility experiments demonstrate that the GVS did not interfere with the MRI scanner functionality and vice versa. The circular silicone electrode was considered the most suitable to apply the galvanic vestibular stimulation. The 1 Hz stimulation sinusoid frequency produced the biggest balance and the less pain sensations when compared to 2 Hz. The GVS was capable of eliciting activation in the precentral and postcentral gyri, in the central sulcus, in the supplementary motor area, in the middle and inferior frontal gyri, in the inferior parietal lobule, in the insula, in the superior temporal gyrus, in the middle cingulate cortex, and in the cerebellum. CONCLUSION: This study shows the development and description of a neurovestibular stimulator that can be safely used inside the MRI scanner room without interfering on its operation and vice versa. The developed GVS could successfully activate the major areas involved with multimodal functions of the vestibular system, demonstrating its validity as a stimulator for neurovestibular research. To the best of our knowledge, this is the first work that shows the development and the construction of a galvanic vestibular stimulator that could be safely used inside the MRI room.

Hellen Mathei, Della-Justina; Tiago, Manczak; Anderson Marcelo, Winkler; Dráulio Barros de, Araújo; Mauren Abreu de, Souza; Edson, Amaro Junior; Humberto Remigio, Gamba.

271

Signalling properties of identified deep cerebellar nuclear neurons related to eye and head movements in the alert cat.  

Science.gov (United States)

1. The spike activity of deep cerebellar nuclear neurons was recorded in the alert cat during spontaneous and during vestibularly and visually induced eye movements. 2. Neurons were classified according to their location in the nuclei, their antidromic activation from projection sites, their sensitivity to eye position and velocity during spontaneous eye movements, and their responses to vestibular and optokinetic stimuli. 3. Type I EPV (eye position and velocity) neurons were located mainly in the posterior part of the fastigial nucleus and activated antidromically almost exclusively from the medial longitudinal fasciculus close to the oculomotor complex. These neurons, reported here for the first time, increased their firing rate during saccades and eye fixations towards the contralateral hemifield. Their position sensitivity to eye fixations in the horizontal plane was 5.3 +/- 2.6 spikes s-1 deg-1 (mean +/- S.D.). Eye velocity sensitivity during horizontal saccades was 0.71 +/- 0.52 spikes s-1 deg-1 s-1. Variability of their firing rate during a given eye fixation was higher than that shown by abducens motoneurons. 4. Type I EPV neurons increased their firing rate during ipsilateral head rotations at 0.5 Hz with a mean phase lead over eye position of 95.3 +/- 9.5 deg. They were also activated by contralateral optokinetic stimulation at 30 deg s-1. Their sensitivity to eye position and velocity in the horizontal plane during vestibular and optokinetic stimuli yielded values similar to those obtained for spontaneous eye movements. 5. Type II neurons were located in both fastigial and dentate nuclei and were activated antidromically from the restiform body, the medial longitudinal fasciculus close to the oculomotor complex, the red nucleus and the pontine nuclei. Type II neurons were not related to spontaneous eye movements. These neurons increased their firing rate in response to contralateral head rotation and during ipsilateral optokinetic stimulation, and decreased it with the oppositely directed movements. 6. Saccade-related neurons were located mostly in the fastigial and dentate nuclei. Fastigial neurons were activated antidromically from the medial longitudinal fasciculus, while dentate neurons were activated from the red nucleus. These neurons fired a burst of spikes whose duration was significantly related to saccade duration. Dentate neurons responded during the omni-directional saccades, while some fastigial neurons fired more actively during contralateral saccades. 7. These three types of neuron represent the output channel for oculomotor signals of the posterior vermis and paravermis. It is proposed that type I EPV neurons correspond to a group of premotor neurons directly involved in oculomotor control.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:7965834

Gruart, A; Delgado-García, J M

1994-07-01

272

To develop behavioral tests of vestibular functioning in the Wistar rat  

Science.gov (United States)

Two tests of vestibular functioning in the rat were developed. The first test was the water maze. In the water maze the rat does not have the normal proprioceptive feedback from its limbs to help it maintain its orientation, and must rely primarily on the sensory input from its visual and vestibular systems. By altering lighting conditions and visual cues the vestibular functioning without visual cues was assessed. Whether there was visual compensation for some vestibular dysfunction was determined. The second test measured vestibular functioning of the rat's behavior on a parallel swing. In this test the rat's postural adjustments while swinging on the swing with the otoliths being stimulated were assessed. Less success was achieved in developing the parallel swing as a test of vestibular functioning than with the water maze. The major problem was incorrect initial assumptions of what the rat's probable behavior on the parallel swing would be.

Nielson, H. C.

1980-01-01

273

The vestibular contribution to the head direction cells signal and navigation  

Directory of Open Access Journals (Sweden)

Full Text Available Spatial learning and navigation depend on neural representations of location and direction within the environment. These representations, encoded by place cells and head direction cells, respectively, are dominantly controlled by visual cues, but require input from the vestibular system. Vestibular signals play an important role in forming spatial representations in both visual and non-visual environments, but the details of this vestibular contribution are not fully understood. Here, we review the role of the vestibular system in generating various spatial signals in rodents, focusing primarily on head direction cells. We also examine the vestibular system’s role in navigation and the possible pathways by which vestibular information is conveyed to higher navigation centers.

JeffreySTaube

2014-04-01

274

A neuroscientific account of how vestibular disorders impair bodily self-consciousness  

Directory of Open Access Journals (Sweden)

Full Text Available The consequences of vestibular disorders on balance, oculomotor control and self-motion perception have been extensively described in humans and animals. More recently, vestibular disorders have been related to cognitive deficits in spatial navigation and memory tasks. Less frequently, abnormal bodily perceptions have been described in patients with vestibular disorders. Altered forms of bodily self-consciousness include distorted body image and body schema, disembodied self-location (out-of-body experience, altered sense of agency, as well as more complex experiences of dissociation and detachment from the self (depersonalization. In this article, I suggest that vestibular disorders create sensory conflict or mismatch in multisensory brain regions, producing perceptual incoherence and abnormal body and self perceptions. This hypothesis is based on recent functional mapping of the human vestibular cortex, showing vestibular projections to the primary and secondary somatosensory cortex and in several multisensory areas found to be crucial for bodily self-consciousness.

ChristopheLopez

2013-12-01

275

A neuroscientific account of how vestibular disorders impair bodily self-consciousness.  

Science.gov (United States)

The consequences of vestibular disorders on balance, oculomotor control, and self-motion perception have been extensively described in humans and animals. More recently, vestibular disorders have been related to cognitive deficits in spatial navigation and memory tasks. Less frequently, abnormal bodily perceptions have been described in patients with vestibular disorders. Altered forms of bodily self-consciousness include distorted body image and body schema, disembodied self-location (out-of-body experience), altered sense of agency, as well as more complex experiences of dissociation and detachment from the self (depersonalization). In this article, I suggest that vestibular disorders create sensory conflict or mismatch in multisensory brain regions, producing perceptual incoherence and abnormal body and self perceptions. This hypothesis is based on recent functional mapping of the human vestibular cortex, showing vestibular projections to the primary and secondary somatosensory cortex and in several multisensory areas found to be crucial for bodily self-consciousness. PMID:24367303

Lopez, Christophe

2013-01-01

276

Electromyographic activity of sternocleidomastoid and masticatory muscles in patients with vestibular lesions  

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This study evaluated the electromyographic characteristics of masticatory and neck muscles in subjects with vestibular lesions. Surface electromyography of the masseter, temporalis and sternocleidomastoid muscles was performed in 19 patients with Ménière's disease, 12 patients with an acute peripheral vestibular lesion, and 19 control subjects matched for sex and age. During maximum voluntary clenching, patients with peripheral vestibular lesions had the highest co-contraction of the sterno...

Tartaglia, Gianluca M.; Stefania Barozzi; Marin Federico; Antonio Cesarani; Ferrario, Virgilio F.

2008-01-01

277

Evaluation of the chemical model of vestibular lesions induced by arsanilate in rats  

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Several animal models of vestibular deficits that mimic the human pathology phenotype have previously been developed to correlate the degree of vestibular injury to cognate vestibular deficits in a time-dependent manner. Sodium arsanilate is one of the most commonly used substances for chemical vestibular lesioning, but it is not well described in the literature. In the present study, we used histological and functional approaches to conduct a detailed exploration of the model of vestibular lesions induced by transtympanic injection of sodium arsanilate in rats. The arsanilate-induced damage was restricted to the vestibular sensory organs without affecting the external ear, the oropharynx, or Scarpa's ganglion. This finding strongly supports the absence of diffusion of arsanilate into the external ear or Eustachian tubes, or through the eighth cranial nerve sheath leading to the brainstem. One of the striking observations of the present study is the complete restructuring of the sensory epithelia into a non sensory epithelial monolayer observed at 3 months after arsanilate application. This atrophy resembles the monolayer epithelia observed postmortem in the vestibular epithelia of patients with a history of lesioned vestibular deficits such as labyrinthectomy, antibiotic treatment, vestibular neuritis, or Ménière's disease. In cases of Ménière's disease, aminoglycosides, and platinum-based chemotherapy, vestibular hair cells are destroyed, regardless of the physiopathological process, as reproduced with the arsanilate model of vestibular lesion. These observations, together with those presented in this study of arsanilate vestibular toxicity, suggest that this atrophy process relies on a common mechanism of degeneration of the sensory epithelia.

Vignaux, G. [INSERM, ERI27, Caen, F-14000 (France); Univ Caen, Caen, F-14000 (France); Chabbert, C.; Gaboyard-Niay, S.; Travo, C. [INSERM U1051, Institut des Neurosciences de Montpellier, Montpellier, F-34090,France (France); Machado, M.L. [INSERM, ERI27, Caen, F-14000 (France); Univ Caen, Caen, F-14000 (France); Denise, P. [INSERM, ERI27, Caen, F-14000 (France); Univ Caen, Caen, F-14000 (France); CHRU Caen, Explorations Fonctionnelles, Caen, F-14000 (France); Comoz, F. [CHRU Caen, Laboratoire d' anatomopathologie, Caen, F-14000 (France); Hitier, M. [CHRU Caen, Service d' Otorhinolaryngologie, Caen, F-14000,France (France); Landemore, G. [CHRU Caen, Laboratoire d' anatomopathologie, Caen, F-14000 (France); Philoxène, B. [INSERM, ERI27, Caen, F-14000 (France); Univ Caen, Caen, F-14000 (France); CHRU Caen, Explorations Fonctionnelles, Caen, F-14000 (France); Besnard, S., E-mail: besnard-s@phycog.org [INSERM, ERI27, Caen, F-14000 (France); Univ Caen, Caen, F-14000 (France); CHRU Caen, Explorations Fonctionnelles, Caen, F-14000 (France)

2012-01-01

278

Vestibular Stimulation on a Motion-Simulator Impacts on Mood States  

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We are familiar with both pleasant and unpleasant psychotropic effects of movements associated with vestibular stimulation. However, there has been no attempt to scientifically explore the impact of different kinds of vestibular stimulation on mood states and biomarkers. A sample of 23 healthy volunteers were subjected to a random sequence of three different passive rotational (yaw, pitch, roll) and translational (heave, sway, surge) vestibular stimulation paradigms using a motion-simulator (...

Winter, L.; Kruger, T. H. C.; Laurens, J.; Engler, H.; Schedlowski, M.; Straumann, D.; Wollmer, M. A.

2012-01-01

279

Origin of efferent fibers of the vestibular apparatus in goldfish : a horseradish peroxidase study  

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After injecting a horseradish peroxidase (HRP) solution into the vestibular apparatus in goldfish (Carassius auratus), cells in the medulla oblongata exhibited retrogradely transported HRP reaction product. These labeled cells were confined to 3 nuclei, i.e. the nucleus motorius tegmenti of Bartelmez (with the most prominent labeled cell groups), the ventral vestibular nucleus (Deiter's nucleus) and the medial vestibular nucleus. We consider these labeled cells to be the origin of the efferen...

Strutz, Ju?rgen; Schmidt, Christian Ludwig; Stu?rmer, Claudia

1980-01-01

280

Cervical and ocular vestibular evoked myogenic potentials test results in individuals with auditory neuropathy spectrum disorders  

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“Auditory neuropathy spectrum disorder” is a clinical disorder where the outer hair cell functioning is intact but the functioning of the auditory nerve is affected. Since, the 8th nerve is constituted by both the auditory and vestibular branch of nerve fibers, there are chances that the vestibular nerve might also be affected. Hence, the current study was carried out in order to determine the functioning of vestibular nerve in individuals with Auditory Neuropathy. A total of 11 participa...

Raja Sharanya; Sujeet Kumar Sinha; Kruthika Shankar

2013-01-01

 
 
 
 
281

Research concerning the release of the vestibular afferents of the vibration induced nystagmus  

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The study comprehended 10 uneffected persons and 60 patients suffering from unilateral vestibular deficit. The results of the caloric stimulation tests, the vestibular evoked myogenic potentials and the vibration induced nystagmus were compared against each other. It revealed that the findings of the caloric stimulation tests and the vibration induced nystagmus were corresponding strongly, whilst those of the vibration induced nystagmus against the vestibular evoked myogenic potentials did no...

Wiblishauser, Kathrin

2005-01-01

282

Physiological and pathophysiological studies on the otolith function in the human vestibular system  

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This book describes physiological and pathophysiological aspects of otolith function. The introduced 10 published papers deals with the receptor function, the pathway within the reflex arch and the influence of otolith function on postural control. Further a vestibular neurofeedback training concept for the rehabilitation of postural control in otolith disorders is presented. The inferior vestibular nerve was electrically stimulated to characterize the sensory origin of vestibular evoked m...

Basta, Dietmar

2010-01-01

283

Reabilitação vestibular em pacientes idosos portadores de vertigem posicional paroxística benigna Vestibular rehabilitation in elderly patients with benign paroxysmal positional vertigo  

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Full Text Available A Vertigem Posicional Paroxística Benigna (VPPB é um distúrbio vestibular no qual os pacientes relatam breves momentos de vertigem e/ou leve instabilidade postural, ocasionados por uma mudança brusca na movimentação cefálica ou corporal. OBJETIVO: Verificar o benefício da reabilitação vestibular, realizada em grupo, em pacientes idosos portadores de VPPB. FORMA DE ESTUDO: Clínico prospectivo. MATERIAL E MÉTODO: Foram selecionados aleatoriamente 16 pacientes portadores de VPPB, todos medicados com extrato de Gingko-biloba (40mg de 12/12h durante 30 dias. Oito deles, que formaram o Grupo Experimental, além do medicamento, foram submetidos à reabilitação vestibular e oito compuseram o Grupo Controle que não realizaram nenhum tipo de exercício. Para avaliação do benefício aplicamos a Escala de Atividades de Vida Diária e Desordens Vestibulares proposta por Cohen e Kimball. Para a análise estatística utilizamos o teste t-student. CONCLUSÃO: Nossos resultados apontaram benefício promovido pela reabilitação vestibular em grupo no tratamento de idosos portadores de VPPB; a avaliação qualitativa mostrou-se instrumento importante para a avaliação de benefício para o tratamento proposto; e a reabilitação vestibular em grupo mostrou ser uma excelente estratégia terapêutica.The Benign Paroxysmal Positional Vertigo (BPPV is a vestibular disorder where the patients complain brief moments of vertigo and/or present postural instability, caused by a brusque change in the cephalic or body movement. AIM: The objective of the present study is certificate the benefit of the vestibular rehabilitation in elderly people with Benign Paroxysmal Positional Vertigo. STUDY DESIGN: Clinical prospective. MATERIAL AND METHOD: Sixteen patients with BPPV were thread with extract of Ginkgo-biloba (40mg of 12/12h during 30 days. Eight patients (the Experimental Group were submitted to vestibular rehabilitation and the other called Control Group, didn't perform any kind of exercises. In order to perform the evaluation of the benefit we used the Scale of Activity of Daily Life and Vestibular Disorders by Kohen and Kimball, and used the t-student test to statistical analysis. CONCLUSION: The vestibular rehabilitation in group showed benefit in the treatment in the Experimental Group; the Scale of Activity of Daily Life and Vestibular Disorders, was an important tool for the qualitative evaluation in our rehabilitation proposal and the vestibular rehabilitation in group showed as an excellent therapeutic strategy.

Carolina R. Resende

2003-08-01

284

Avaliação otoneurológica em crianças com queixa de dificuldades escolares: pesquisa da função vestibular Otoneurologic evaluation in children with school difficulties: vestibular function investigation  

Directory of Open Access Journals (Sweden)

Full Text Available Segundo a literatura, a disfunção vestibular infantil pode afetar consideravelmente a habilidade de comunicação e o desempenho escolar. OBJETIVO: Estudar a função vestibular em crianças com dificuldades escolares e suas queixas vestibulares. ESTUDO DE CASO: Estudo Clínico com coorte transversal. MATERIAL E MÉTODOS: Foram estudadas 50 crianças entre 7 e 12 anos, que freqüentavam escolas públicas de Piracicaba durante os anos de 2004 e 2005. Os procedimentos foram: anamnese; exame otorrinolaringológico; exame audiológico e avaliação vestibular. RESULTADOS: Das crianças avaliadas, 62,0% não relataram dificuldades escolares e 38,0% referiram ter dificuldades. A queixa geral mais comum foi de tontura (36,0%, e o sintoma mais comum no ambiente escolar foi de cefaléia (50,0%. Encontramos 74,2% de exame vestibular normal nas crianças sem dificuldades escolares e 31,6% de normalidade nas crianças com dificuldades. Encontramos alterações vestibulares de origem periférica irritativa tanto unilateral como bilateral, num total de 68,4% para as crianças com dificuldades escolares e um total de 25,8% para crianças sem dificuldades escolares. CONCLUSÃO: A queixa de atordoamento, o sintoma de náuseas e as dificuldades em ler e copiar apresentaram uma relação estatisticamente significante. Todas as alterações vestibulares encontradas foram de origem periférica irritativa. Os dados revelaram uma relação estatisticamente significante.According to the literature, child vestibular dysfunctions can considerably affect their ability of communication and school performance. AIM: to study the vestibular function in children with school difficulties and associated symptoms. CASE STUDY: Clinical study with transversal cohort. METHOD: Research subjects were 50 school children between 7 and 12 years old, from a public school of Piracicaba city, during the years 2004 and 2005. The procedure was based on: anamnesis; otorrinolaryngologic evaluation; audiologic evaluation and vestibular evaluation. RESULTS: All children assessed, 62.0% did not have school difficulties and 38.0% had school difficulties. Dizziness was the most common general complaint (36.0%. Migraine was the most common symptom regarding the school environment (50.0%. We found a high rate of normal vestibular condition (74.2% in children without school difficulties and low normality rate in those with school difficulties (31.6%. All found vestibular alterations, both unilateral and bilateral, had been of peripheral irritative origin, accounting for 68.4% of cases for children with school difficulties and 25.8% for children without school difficulties. CONCLUSION: Dizziness, nausea, reading and copying difficulties presented a statistically significant relationship between the studied variables. All found vestibular alterations had been of peripheral irritative origin. Data showed a statistically significant relationship among variables.

Eloisa Sartori Franco

2007-12-01

285

Avaliação otoneurológica em crianças com queixa de dificuldades escolares: pesquisa da função vestibular / Otoneurologic evaluation in children with school difficulties: vestibular function investigation  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Segundo a literatura, a disfunção vestibular infantil pode afetar consideravelmente a habilidade de comunicação e o desempenho escolar. OBJETIVO: Estudar a função vestibular em crianças com dificuldades escolares e suas queixas vestibulares. ESTUDO DE CASO: Estudo Clínico com coorte transversal. MAT [...] ERIAL E MÉTODOS: Foram estudadas 50 crianças entre 7 e 12 anos, que freqüentavam escolas públicas de Piracicaba durante os anos de 2004 e 2005. Os procedimentos foram: anamnese; exame otorrinolaringológico; exame audiológico e avaliação vestibular. RESULTADOS: Das crianças avaliadas, 62,0% não relataram dificuldades escolares e 38,0% referiram ter dificuldades. A queixa geral mais comum foi de tontura (36,0%), e o sintoma mais comum no ambiente escolar foi de cefaléia (50,0%). Encontramos 74,2% de exame vestibular normal nas crianças sem dificuldades escolares e 31,6% de normalidade nas crianças com dificuldades. Encontramos alterações vestibulares de origem periférica irritativa tanto unilateral como bilateral, num total de 68,4% para as crianças com dificuldades escolares e um total de 25,8% para crianças sem dificuldades escolares. CONCLUSÃO: A queixa de atordoamento, o sintoma de náuseas e as dificuldades em ler e copiar apresentaram uma relação estatisticamente significante. Todas as alterações vestibulares encontradas foram de origem periférica irritativa. Os dados revelaram uma relação estatisticamente significante. Abstract in english According to the literature, child vestibular dysfunctions can considerably affect their ability of communication and school performance. AIM: to study the vestibular function in children with school difficulties and associated symptoms. CASE STUDY: Clinical study with transversal cohort. METHOD: Re [...] search subjects were 50 school children between 7 and 12 years old, from a public school of Piracicaba city, during the years 2004 and 2005. The procedure was based on: anamnesis; otorrinolaryngologic evaluation; audiologic evaluation and vestibular evaluation. RESULTS: All children assessed, 62.0% did not have school difficulties and 38.0% had school difficulties. Dizziness was the most common general complaint (36.0%). Migraine was the most common symptom regarding the school environment (50.0%). We found a high rate of normal vestibular condition (74.2%) in children without school difficulties and low normality rate in those with school difficulties (31.6%). All found vestibular alterations, both unilateral and bilateral, had been of peripheral irritative origin, accounting for 68.4% of cases for children with school difficulties and 25.8% for children without school difficulties. CONCLUSION: Dizziness, nausea, reading and copying difficulties presented a statistically significant relationship between the studied variables. All found vestibular alterations had been of peripheral irritative origin. Data showed a statistically significant relationship among variables.

Eloisa Sartori, Franco; Ivone, Panhoca.

2007-12-01

286

Vestibular function in the temporal and parietal cortex: distinct velocity and inertial processing pathways  

Science.gov (United States)

A number of behavioral and neuroimaging studies have reported converging data in favor of a cortical network for vestibular function, distributed between the temporo-parietal cortex and the prefrontal cortex in the primate. In this review, we focus on the role of the cerebral cortex in visuo-vestibular integration including the motion sensitive temporo-occipital areas i.e., the middle superior temporal area (MST) and the parietal cortex. Indeed, these two neighboring cortical regions, though they both receive combined vestibular and visual information, have distinct implications in vestibular function. In sum, this review of the literature leads to the idea of two separate cortical vestibular sub-systems forming (1) a velocity pathway including MST and direct descending pathways on vestibular nuclei. As it receives well-defined visual and vestibular velocity signals, this pathway is likely involved in heading perception and rapid top-down regulation of eye/head coordination and (2) an inertial processing pathway involving the parietal cortex in connection with the subcortical vestibular nuclei complex responsible for velocity storage integration. This vestibular cortical pathway would be implicated in high-order multimodal integration and cognitive functions, including world space and self-referential processing. PMID:25071481

Ventre-Dominey, Jocelyne

2014-01-01

287

Otolith-ocular responses in patients with surgically confirmed unilateral peripheral vestibular loss.  

Science.gov (United States)

The chronic effects of unilateral peripheral vestibular loss (UPVL) are influenced by vestibular compensation. This study documents the balance-related symptoms and quantitative vestibular laboratory testing of 20 patients with surgically confirmed UPVL. Included are measures of the semicircular canal-ocular reflex, the otolith-ocular reflex, and both static and dynamic semicircular canal-otolith-interaction. This study differs from previous studies of patients with UPVL in that a large number of patients with surgically confirmed lesions were tested with three types of off-vertical axis rotation, several of the patients had anatomically preserved superior vestibular nerves, and self-perceived level of disability related to dizziness and imbalance were available. Results confirmed previously reported changes in the vestibulo-ocular reflex of patients with UPVL. Also, there was no apparent effect of anatomically preserving the superior vestibular nerve during surgical resection of vestibular schwannomas based on either subjective or objective measures of vestibular dysfunction. Further, there were no apparent correlations between subjective measures of dizziness and imbalance and objective measures of vestibulo-ocular function. These results have clinical implications for the management of patients with unilateral vestibular loss and provide insights into the process of vestibular compensation especially with respect to the otolith-ocular reflex. PMID:14757917

Furman, Joseph M; Hsu, Li-Chi; Whitney, Susan L; Redfern, Mark S

2003-01-01

288

[Present situation and development of ocular vestibular-evoked myogenic potential].  

Science.gov (United States)

Myogenic potentials evoked by air conducted sound (ACS), bone conducted vibration (BCV) or galvanic pulses can be recorded with surface electrodes over contracted muscles. These myogenic potentials are of vestibular origin (utricle and saccule) and so these potentials are called vestibular evoked myogenic potentials (VEMPs). Since the vestibular system has projections to many muscle systems, there are many such VEMPs. In this review, we discuss the generated origin, response pathway, waveform characteristics and clinical application of ocular vestibular-evoked myogenic potential (oVEMP). PMID:23833997

Hu, Juan; Xu, Min; Zhang, Qing

2013-04-01

289

Vestibular Function in the Temporal and Parietal Cortex: Distinct Velocity and Inertial Processing Pathways  

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Full Text Available A number of behavioural and neuroimaging studies have reported converging data in favour of a cortical network for vestibular function, distributed between the temporo-parietal cortex and the prefrontal cortex in the primate. In this review, we focus on the role of the cerebral cortex in visuo-vestibular integration including the motion sensitive temporo-occipital areas i.e. the middle superior temporal area (MST and the parietal cortex. Indeed these two neighbouring cortical regions, though they both receive combined vestibular and visual information, have distinct implications in vestibular function. In sum, this review of the literature leads to the idea of two separate cortical vestibular sub-systems forming (1 a velocity pathway including MST and direct descending pathways on vestibular nuclei. As it receives well defined visual and vestibular velocity signals, this pathway is likely involved in heading perception and rapid top-down regulation of eye/head coordination and (2 an inertial processing pathway involving the parietal cortex in connection with the subcortical vestibular nuclei complex responsible for velocity storage integration. This vestibular cortical pathway would be implicated in high order multimodal integration and cognitive functions, including world space and self- referential processing.

JocelyneVentre-Dominey

2014-07-01

290

Research on biophysical evaluation of the human vestibular system  

Science.gov (United States)

The human vestibular function was studied by the combined approach of advanced measurement and mathematical modelling. Fundamental measurements of some physical properties of endolymph and perilymph, combined with nystagmus measurements and fluid mechanical analysis of semicircular canal function furthered the theory of canal mechanical response to angular acceleration, caloric stimulation and relating linear acceleration. The effects of adaptation seen at low frequency angular stimulation were studied and modelled to remove some shortcomings of the torsion pendulum models. Otolith function was also studied experimentally and analytically, leading to a new set of models for subjective orientation. Applications to special problems of space, including the case of rotating spacecraft were investigated and the interaction of visual and vestibular cues and their relation to proprioceptive information was explored relative to postural control.

Young, L. R.

1974-01-01

291

A model describing vestibular detection of body sway motion.  

Science.gov (United States)

An experimental technique was developed which facilitated the formulation of a quantitative model describing vestibular detection of body sway motion in a postural response mode. All cues, except vestibular ones, which gave a subject an indication that he was beginning to sway, were eliminated using a specially designed two-degree-of-freedom platform; body sway was then induced and resulting compensatory responses at the ankle joints measured. Hybrid simulation compared the experimental results with models of the semicircular canals and utricular otolith receptors. Dynamic characteristics of the resulting canal model compared closely with characteristics of models which describe eye movement and subjective responses to body rotational motions. The average threshold level, in the postural response mode, however, was considerably lower. Analysis indicated that the otoliths probably play no role in the initial detection of body sway motion.

Nashner, L. M.

1971-01-01

292

[Audio-vestibular functions in patients with hemifacial spasm].  

Science.gov (United States)

Audio-vestibular functions and its laterality were evaluated preoperatively on the affected side and the non-affected side of 57 patients operated upon to relieve hemifacial spasm (HFS). One patient had hearing impairment and tinnitus on the affected side and showed abrupt high tone sensorineural loss, directional preponderance and ABR abnormalities. On another patient, the latencies for wave III and V from the affected ear were prolonged, while there was no audiovestibular symptoms. However, there was no significant difference in audio-vestibular symptoms, ABR findings, pure tone thresholds and caloric results between the affected ears and the non-affected ears of the remainder. We believe that HFS and the microvascular compression of the eighth cranial nerve are two different diseases. PMID:2621500

Fukaya, T; Nomura, Y

1989-12-01

293

LEITURA DE IMAGENS: A ANÁLISE DE UMA PROVA DE VESTIBULAR  

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Full Text Available Com a finalidade de refletir sobre o discurso oficial relacionado à habilidade de leitura de imagem no Ensino Médio, é feita uma análise da prova de vestibular da Universidade Federal de Goiás considerada aqui como a materialização e prática do discurso oficial que possibilita a observação das capacidades e habilidades de leitura. Sendo a linha de pesquisa adotada a Análise do Discurso, alguns conceitos de Foucault, Bakhtin, Maingueneau e outros serão mobilizados. Devido à necessidade de um recorte, o corpus é a prova de vestibular 2011-1. Este trabalho faz parte de uma reflexão maior sobre a leitura, considerando a leitura e interpretação de textos multimodais. Palavras-Chaves: Discurso. Universidade Federal de Goiás. Leitura. Multimodal.

Aline Rezende Belo Alves

2013-10-01

294

[Cystic lesion in the area of the vestibular folds].  

Science.gov (United States)

Warthin tumor is the second most frequently seen benign tumor of the salivary glands and is generally located in the parotid gland. Although extraparotideal manifestations in the small salivary glands are rare, the occurrence of cystic lesions in the area of the nasopharynx, eyelid, oral cavity or vestibular folds should include the Warthin tumor in the differential diagnosis. The therapy of choice is complete surgical tumor resection. PMID:22051803

Pump, J B; Schröck, A; Ozreti?, L; Bootz, F

2012-03-01

295

Galvanic Vestibular Stimulation in Hemi-Spatial Neglect  

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Full Text Available Hemi-spatial neglect is an attentional disorder in which the sufferer fails to acknowledge or respond to stimuli appearing in contralesional space. In recent years, it has become clear that a measurable reduction in contralesional neglect can occur during galvanic vestibular stimulation, a technique by which transmastoid, small amplitude current induces lateral, attentional shifts via asymmetric modulation of the left and right vestibular nerves. However, it remains unclear whether this reduction persists after stimulation is stopped. To estimate longevity of effect, we therefore conducted a double-blind, randomized, dose-response trial involving a group of stroke patients suffering from left-sided neglect (n=52, mean age=66 years. To determine whether repeated sessions of galvanic vestibular stimulation more effectively induce lasting relief than a single session, participants received 1, 5, or 10 sessions, each lasting 25mins, of sub-sensory, left-anodal right-cathodal noisy direct current (mean amplitude=1mA. Ninety five percent confidence intervals indicated that all three treatment arms showed a statistically significant improvement between the pre-stimulation baseline and the final day of stimulation on the primary outcome measure, the conventional tests of the Behavioural Inattention Test. More remarkably, this change (mean change=28%, SD=18 was still evident 1month later. Secondary analyses indicated an allied increase of 20% in median Barthel Index score, a measure of functional capacity, in the absence of any adverse events or instances of participant non-compliance. Together these data suggest that galvanic vestibular stimulation, a simple, cheap technique suitable for home-based administration, may produce lasting reductions in neglect that are clinically important. Further protocol optimization is now needed ahead of a larger effectiveness study.

David Wilkinson

2014-01-01

296

JNK signaling in neomycin-induced vestibular hair cell death  

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Mechanosensory hair cells are susceptible to apoptotic death in response to exposure to ototoxic drugs, including aminoglycoside antibiotics. The c-Jun n-terminal kinase (JNK) is a stress-activated protein kinase that can promote apoptotic cell death in a variety of systems. Inhibition of the JNK signaling pathway can prevent aminoglycoside-induced death of cochlear and vestibular sensory hair cells. We used an in vitro preparation of utricles from adult mice to examine the role of JNK activa...

Sugahara, Kazuma; Rubel, Edwin W.; Cunningham, Lisa L.

2006-01-01

297

Magnetic Vestibular Stimulation in Subjects with Unilateral Labyrinthine Disorders  

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Full Text Available We recently discovered that static magnetic fields from high-strength MRI machines induce nystagmus in all normal humans, and that a magnetohydrodynamic (MHD Lorentz force, derived from ionic currents in the endolymph and pushing on the cupula, best explains this effect. Individuals with no labyrinthine function have no nystagmus. The influence of magnetic vestibular stimulation (MVS in individuals with unilateral loss of labyrinthine function is unknown and may provide insight into mechanism of MVS. These individuals should experience MVS, but with differences consistent with their residual labyrinthine function. We recorded eye movements in the static magnetic field of a 7T MRI machine in nine individuals with unilateral labyrinthine hypofunction, as determined by head impulse testing and vestibular-evoked myogenic potentials (VEMP. Eye movements were recorded using infrared videooculography. Static head positions were varied in pitch with the body supine, and slow-phase eye velocity (SPV was assessed. All subjects exhibited predominantly horizontal nystagmus after entering the magnet head-first, lying supine. The SPV direction reversed when entering feet-first. Pitching chin-to-chest caused subjects to reach a null point for horizontal SPV. Right unilateral vestibular hypofunction (UVH subjects developed slow-phase-up nystagmus and left UVH subjects, slow-phase-down nystagmus. Vertical and torsional components were consistent with superior semicircular canal excitation or inhibition, respectively, of the intact ear. These findings provide compelling support for the hypothesis that MVS is a result of a Lorentz force and suggest that the function of individual structures within the labyrinth can be assessed with MVS. As a novel method of comfortable and sustained labyrinthine stimulation, MVS can provide new insights into vestibular physiology and pathophysiology.

BryanKevinWard

2014-03-01

298

Integration of vestibular and proprioceptive signals for spatial updating.  

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Spatial updating during self-motion typically involves the appropriate integration of both visual and non-visual cues, including vestibular and proprioceptive information. Here, we investigated how human observers combine these two non-visual cues during full-stride curvilinear walking. To obtain a continuous, real-time estimate of perceived position, observers were asked to continuously point toward a previously viewed target in the absence of vision. They did so while moving on a large circular treadmill under various movement conditions. Two conditions were designed to evaluate spatial updating when information was largely limited to either proprioceptive information (walking in place) or vestibular information (passive movement). A third condition evaluated updating when both sources of information were available (walking through space) and were either congruent or in conflict. During both the passive movement condition and while walking through space, the pattern of pointing behavior demonstrated evidence of accurate egocentric updating. In contrast, when walking in place, perceived self-motion was underestimated and participants always adjusted the pointer at a constant rate, irrespective of changes in the rate at which the participant moved relative to the target. The results are discussed in relation to the maximum likelihood estimation model of sensory integration. They show that when the two cues were congruent, estimates were combined, such that the variance of the adjustments was generally reduced. Results also suggest that when conflicts were introduced between the vestibular and proprioceptive cues, spatial updating was based on a weighted average of the two inputs. PMID:21590262

Frissen, Ilja; Campos, Jennifer L; Souman, Jan L; Ernst, Marc O

2011-07-01

299

Vestibular evoked potentials in response to direct unilateral mechanical stimulation.  

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Evoked potentials produced by direct unilateral mechanical stimulation of the cannulated horizontal semicircular canal were investigated parametrically in anesthetized adult cats (40 mg/kg pentobarbital). Stimuli were fluid pressure pulses in a closed hydraulic system (no net flow), which was coupled to the lateral semicircular canal near the ampulla. Hydraulic waveform output and fluid pressure was monitored in situ via a parallel hydraulic circuit during experiments. Maximum fluid displacement at the level of the horizontal canal was 0.025 microliters. The intensity, duration, and presentation rate of the stimulus were varied during experiments. Field potentials were recorded differentially using subdermal electrodes, with the active lead in the region of the mastoid referenced to a distant nasal site. A total of 256 trials was accumulated for each run using an averaging computer. Evoked responses were physiologically vulnerable and reproducible, with little variance among animals. Response amplitude increased monotonically until saturation was noted and responses followed the temporal structure of the pressure wave. Polarity reversal with differing electrode placement suggests that the generator site lies within the mastoid. Further, intense broad-band acoustic stimuli and eighth nerve sectioning did not affect the vestibular evoked potentials, but could be shown to abolish the auditory evoked potentials. Results of these experiments support the notion that vestibular evoked potentials are related to the first derivative of the pressure pulse waveforms. Future experiments will be directed toward the assessment of vestibular physiology and pharmacology with this evoked response method. PMID:2496377

Coale, F S; Walsh, E J; McGee, J; Konrad, H R

1989-03-01

300

Vestibular evoked myogenic potentials are intact in cervical dystonia.  

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Vestibular dysfunction has been reported in patients with cervical dystonia (CD), but it is still unclear whether the abnormalities occur as part of the CD syndrome or whether they arise from the abnormal posture and movement of the head. We compared vestibular-evoked myogenic potentials (VEMPs) recorded from the affected neck muscles (i.e., cervical VEMPs) with those recorded from muscles unaffected by the dystonia, the extraocular muscles (i.e., ocular VEMPs). We compared 21 patients and age-matched normal controls to investigate whether these short-latency reflexes are altered in CD. We also measured subjective visual horizontal (SVH). Seven patients had not received botulinum toxin treatment (naïve group), 10 were receiving regular injections (treatment group), and four had previously received treatment but had developed antibodies (antibody group). Both cervical and ocular VEMPs were present in the majority of patients and controls. For both reflexes, there were no significant differences between stimulation of the two sides of the head, between the treatment groups, or between the patients and controls. There was also no difference in degree of deviation of SVH between the groups. Our results showed that VEMPs can be reliably recorded from both the neck and extraocular muscles in patients with CD, even after long disease or treatment durations, and provide evidence for intact short-latency vestibular reflexes in CD. PMID:20960477

Rosengren, Sally M; Colebatch, James G

2010-12-15

 
 
 
 
301

Desempenho no vestibular, background familiar e evasão: evidências da UFPE  

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Full Text Available Este artigo tem como objetivo compreender a decisão de evasão de estudantes universitários, assunto ainda pouco entendido no Brasil. Ênfase é dada à relação entre renda, desempenho no vestibular, evasão e a probabilidade de tentar nova carreira em novo vestibular. Atenção também é dada ao efeito escola pública e cursinho pré-vestibular. Os resultados mostram que renda tem papel fundamental não só por proporcionar aos mais ricos melhores condições de estudo (escolas privadas, cursinhos, mas também por possibilitar ao aluno maior oportunidade de escolha da carreira que melhor se adeque as suas aptidões, favorecendo assim a permanência da desigualdade.The main objective of this paper is to understand university students' dropout decision, which is an area still not well studied in Brazil. Particular atention is given to the relationship between income, performance, dropout and the decision to re-take the exam in an attempt to switch careers. The effect of public schools and tutoring classes are also estimated. Results show that income not only provide the students with a better study environment (through private schools and tutoring classes but also allow for the posibility of trying different careers until a better student-career match is made, favoring the persistence of inequality.

Breno Sampaio

2011-06-01

302

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

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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 unilateral stroke. Results Our data demonstrate that patients with lesions of the posterior IC have an abnormal tilt of SVV. Furthermore, re-analysing data of 20 patients from a previous study, we found a positive correlation between thermal perception contralateral to the stroke and the severity of the SVV tilt. Conclusions We conclude that the IC is a sensory brain region where different modalities might interact. PMID:24392273

Baier, Bernhard; Zu Eulenburg, Peter; Best, Christoph; Geber, Christian; Müller-Forell, Wibke; Birklein, Frank; Dieterich, Marianne

2013-09-01

303

Desempenho no vestibular, background familiar e evasão: evidências da UFPE  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Este artigo tem como objetivo compreender a decisão de evasão de estudantes universitários, assunto ainda pouco entendido no Brasil. Ênfase é dada à relação entre renda, desempenho no vestibular, evasão e a probabilidade de tentar nova carreira em novo vestibular. Atenção também é dada ao efeito esc [...] ola pública e cursinho pré-vestibular. Os resultados mostram que renda tem papel fundamental não só por proporcionar aos mais ricos melhores condições de estudo (escolas privadas, cursinhos), mas também por possibilitar ao aluno maior oportunidade de escolha da carreira que melhor se adeque as suas aptidões, favorecendo assim a permanência da desigualdade. Abstract in english The main objective of this paper is to understand university students' dropout decision, which is an area still not well studied in Brazil. Particular atention is given to the relationship between income, performance, dropout and the decision to re-take the exam in an attempt to switch careers. The [...] effect of public schools and tutoring classes are also estimated. Results show that income not only provide the students with a better study environment (through private schools and tutoring classes) but also allow for the posibility of trying different careers until a better student-career match is made, favoring the persistence of inequality.

Breno, Sampaio; Yony, Sampaio; Euler P. G. de, Mello; Andrea S, Melo.

2011-06-01

304

Purchase decision-making is modulated by vestibular stimulation  

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Full Text Available Purchases are driven by consumers’ product preferences and price considerations. Using caloric vestibular stimulation (CVS, we investigated the role of vestibular-affective circuits in purchase decision-making. CVS is an effective non-invasive brain stimulation method, which activates vestibular and overlapping emotional circuits (e.g. the insular cortex and the anterior cingulate cortex. Subjects were exposed to CVS and sham stimulation while they performed two purchase decision-making tasks. In Experiment 1 subjects had to decide whether to purchase or not. CVS significantly reduced probability of buying a product. In Experiment 2 subjects had to rate desirability of the products and willingness to pay while they were exposed to CVS and sham stimulation. CVS modulated desirability of the products but not willingness to pay. The results suggest that CVS interfered with emotional circuits and thus attenuated the pleasant and rewarding effect of acquisition, which in turn reduced purchase probability. The present findings contribute to the rapidly growing literature on the neural basis of purchase decision-making.

NoraPreuss

2014-02-01

305

Purchase decision-making is modulated by vestibular stimulation.  

Science.gov (United States)

Purchases are driven by consumers' product preferences and price considerations. Using caloric vestibular stimulation (CVS), we investigated the role of vestibular-affective circuits in purchase decision-making. CVS is an effective noninvasive brain stimulation method, which activates vestibular and overlapping emotional circuits (e.g., the insular cortex and the anterior cingulate cortex (ACC)). Subjects were exposed to CVS and sham stimulation while they performed two purchase decision-making tasks. In Experiment 1 subjects had to decide whether to purchase or not. CVS significantly reduced probability of buying a product. In Experiment 2 subjects had to rate desirability of the products and willingness to pay (WTP) while they were exposed to CVS and sham stimulation. CVS modulated desirability of the products but not WTP. The results suggest that CVS interfered with emotional circuits and thus attenuated the pleasant and rewarding effect of acquisition, which in turn reduced purchase probability. The present findings contribute to the rapidly growing literature on the neural basis of purchase decision-making. PMID:24600365

Preuss, Nora; Mast, Fred W; Hasler, Gregor

2014-01-01

306

Unilateral vestibular failure suppresses cortical visual motion processing.  

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Patients with unilateral vestibular failure (UVF) experience oscillopsia (apparent motion of the visual scene) during rapid head movements due to increased retinal slip caused by vestibulo-ocular reflex impairment. Oscillopsia is always smaller than the net retinal slip and decreases over time in patients with acquired vestibular loss; this correlates with increased thresholds for visual motion detection and increased tolerance to retinal slip. We investigated the underlying cortical adaptive processes using visual motion stimulation during blood oxygen level-dependent (BOLD) fMRI. Optokinetic nystagmus was elicited in seven patients with right-sided and seven patients with left-sided unilateral vestibular neurectomy and in seven age- and gender-matched healthy controls. Patients showed diminished activation of bilateral visual cortex areas (including the motion-sensitive area MT/V5, cuneus, middle occipital, fusiform and lingual areas) and ocular motor regions compared to their controls during visual motion stimulation. Concurrent BOLD signal decreases of temporo-parietal and insular multisensory cortical areas occurred in controls and patients. The diminished activation of visual motion processing areas plausibly reflects an adaptive mechanism that suppresses distressing oscillopsia in patients with UVF and thereby stabilizes the perceived visual surroundings. This study provides for the first time neuroimaging evidence of suppressed cortical visual motion processing in patients with vestibulopathy. PMID:18321924

Deutschländer, Angela; Hüfner, Katharina; Kalla, Roger; Stephan, Thomas; Dera, Thomas; Glasauer, Stefan; Wiesmann, Martin; Strupp, Michael; Brandt, Thomas

2008-04-01

307

Sensory vestibular contributions to constructing internal models of self-motion  

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The ability to navigate in the world and execute appropriate behavioral and motor responses depends critically on our capacity to construct an accurate internal representation of our current motion and orientation in space. Vestibular sensory signals are among those that may make an essential contribution to the construction of such 'internal models'. Movement in a gravitational environment represents a situation where the construction of internal models becomes particularly important because the otolith organs, like any linear accelerometer, sense inertial and gravitational accelerations equivalently. Otolith afferents thus provide inherently ambiguous motion information, as they respond identically to translation and head reorientation relative to gravity. Resolution of this ambiguity requires the nonlinear integration of linear acceleration and angular velocity cues, as predicted by the physical equations of motion. Here, we summarize evidence that during translations and tilts from upright the firing rates of brainstem and cerebellar neurons encode a combination of dynamically processed semicircular canal and otolith signals appropriate to construct an internal model representation of the computations required for inertial motion detection.

Green, Andrea M.; Shaikh, Aasef G.; Angelaki, Dora E.

2005-09-01

308

Doença vestibular periférica decorrente de osteoartropatia temporoioídea em um eqüino / Peripheral vestibular disease associated with temporohyoid osteoarthropathy in a horse  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Um eqüino com 22 anos de idade apresentou síndrome vestibular periférica associada à paralisia de nervo facial esquerdo devido à osteoartropatia temporoioídea. O exame endoscópico das bolsas guturais mostrou alteração de contorno da bula timpânica esquerda e aumento de volume da extremidade proximal [...] do osso estiloióide do mesmo lado. Abstract in english A 22-year-old gelding showed vestibular syndrome associated with left facial nerve paralysis due to temporohyoid osteoarthropathy and the diagnostic was confirmed by guttural pouch endoscopic examination. The exam revealed abnormal contour of the left tympanic bulla and an enlargement of the proxima [...] l part of the left stylohyoid bone.

Alexandre Secorun, Borges; José Luiz de Mello, Nicoletti; Armen, Thomassian; Ênio Pedone, Bandarra; Ana Laura, Angeli.

309

Potencial evocado miogênico vestibular: novas perspectivas diagnósticas em esclerose múltipla / Vestibular evoked myogenic potential: new perspectives in multiple sclerosis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: Avaliar o potencial evocado miogênico vestibular em pacientes com esclerose múltipla, como método de auxílio diagnóstico. FORMA DE ESTUDO: Caso-controle. MATERIAL E MÉTODO: Estudamos um grupo-controle (n=15) de indivíduos normais e um grupo experimental (n=15) que foi composto por paciente [...] s com diagnóstico de esclerose múltipla. Ambos os grupos foram submetidos ao exame de potencial evocado miogênico vestibular. Em cada orelha foram aplicados 200 estímulos na forma de cliques e repetidos por 2 ciclos consecutivos com objetivo de avaliar a reprodutibilidade. Os eletrodos ativos de superfície foram colocados no S‡superior do músculo esternocleidomastoideo e de referência na borda anterior da clavícula ipsilateral. Os indivíduos foram instruídos à rotação lateral da cabeça em direção contralateral à orelha estimulada. RESULTADOS: Obtivemos no potencial evocado miogênico vestibular respostas rápidas, reprodutíveis e bifásicas. A latência das ondas P1 e N2 e amplitude P1-N2 apresentaram um maior valor no grupo experimental quando comparada com o grupo-controle. Não observamos diferença significativa nas respostas das ondas P1 e N2 e amplitude P1-N2 quando comparamos as orelhas. Verificamos que os indivíduos com esclerose múltipla apresentaram ausência de respostas em 30% dos casos. Ao avaliarmos os indivíduos do grupo experimental com sintomas otoneurológicos e compararmos com os pacientes sem sintomas, observamos que a latência da onda P1, N2 e amplitude P1-N2 estiveram maiores nos casos sintomáticos. CONCLUSÃO: O potencial evocado miogênico vestibular foi considerado um bom método de auxílio diagnóstico da via vestíbulo-espinal nos casos de esclerose múltipla. Abstract in english AIM: To evaluate vestibular evoked myogenic potentials in patients with multiple sclerosis as method of diagnostic support. STUDY DESIGN: Case-control. MATERIAL AND METHOD: We studied a group of normal individuals (n=15) and a Studied group (n=15) that comprised patients with diagnosis of multiple s [...] clerosis. Both groups were submitted to vestibular evoked myogenic potential exam. In each ear it was applied 200 stimuli by clicks and repeated for 2 consecutive cycles with the purpose of evaluating reproducibility. The active electrode of surface was put on the superior S‡of sternocleidomastoid muscle and the reference electrode on the anterior border of the clavicle. The individuals were instructed to rotate theirs head to the opposite side to the stimulated ear. RESULTS: Vestibular evoked myogenic potential responses were prompt, reproducible and biphasic. The latency of wave P1 and N2 and P1-N2 amplitude showed a higher value in the studied group when compared with the normal group. There was no significant difference when the ears were compared in P1 and N2 amplitude. We noticed that individuals with multiple sclerosis showed no response in 30% of the cases. In evaluating the individuals of the Studied group with otoneurology symptoms and compared with individuals without symptoms, it was observed that P1 and N2 latencies and P1-N2 amplitude were higher in symptomatic cases. CONCLUSION: Vestibular evoked myogenic potential was considered a good method of diagnostic support of vestibulospinal tract in cases of multiple sclerosis.

Renata Chade, Aidar; Fábio A., Suzuki.

310

[Interdisciplinary approach to vestibular system impairment].  

Science.gov (United States)

In the first part of this review the definition of vertigo/dizziness was discussed. The major difference between the two signs is the existence of the direction, which is specific for vertigo. Dizziness is a frequent complaint in the clinical practice. Its frequency is increasing with advance of age, to intimate the play of declining cognitive process in the pathogenesis of its. The popular health significance of vertigo is in the rowing number of the patients. The onset of the most cases with acute vertigo appears between secundums and minutes so the patients will be provided in circumstances of emergency department. First of all three form should be take into account: neuronitis vestibularis, benign paroxysmal positional vertigo and Meniere syndrome. Without typical periferal signs of vertigo, central cause should be searched, principally stroke (lysis possibility). The differential diagnose of the different dizziness/vertigo forms according to the elapsed time of the onset or congenital and acquired nystagmus was created in tables. The recommendations of the therapy of acute and chronic dizziness/vertigo syndromes are, lack of results of evidence based trials doubtful. The more often used drugs based on clinical trials are discussed as vinpocetine, betahistine and piracetam. The in vitro and in vivo data suggest that the last molecule is eligible to use both in periferal and central type of vertigo syndromes. PMID:21545007

Pongrácz, Endre

2011-03-30

311

Contribution of the eighth nerve and cranial nerve nuclei to the short-latency vestibular evoked potentials in cats.  

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The object of this study was to assess the contributions of the vestibular nerve and various cranial nerve nuclei to the short-latency vestibular evoked potentials in cat. The following nuclei were investigated: vestibular nuclei and the third, sixth, and tenth cranial nerve nuclei. In unilateral labyrinthectomized cats, we performed suboccipital craniectomy and partial cerebellectomy to place bipolar electrodes into the neural structures under investigation. The surface-recorded vestibular evoked potentials (far field) were compared with the potentials recorded intracranially in response to the same acceleration impulses. The exact locations were later confirmed histologically. Reversible lesions also were induced by injection of lidocaine 2%. The results indicate that the first wave of the vestibular evoked potentials originates in the vestibular nerve, and the second wave is mainly generated in the superior and medial vestibular nuclei. The third, sixth, and tenth cranial nerve nuclei apparently contribute to the later waves of the vestibular evoked potentials, particularly waves 3 and 4. PMID:9051061

Li, G; Elidan, J; Meyler, Y; Sohmer, H

1997-02-01

312

Multiple intracranial lipomas, hypogenetic corpus callosum and vestibular schwannoma: an unusual spectrum of MR findings in a patient.  

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Full Text Available We describe imaging findings of a patient with multiple intracranial lipomas, hypogenetic corpus callosum and a vestibular schwannoma. We did not find association of intracranial lipomas and vestibular schwannoma in English literature.

Shah J

1999-04-01

313

Configuração das pregas vestibulares em laringes de pacientes com nódulo vocal Vestibular folds configuration in vocal nodule  

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O nódulo vocal está entre as laringopatias mais comuns que resultam em alterações na função vocal. O mecanismo da produção da fala é complexo e exige interação de diversos sistemas do organismo humano. A importância das pregas vocais na fisiologia e na formação da fonte sonora glótica é evidente; contudo, quanto à participação das pregas vestibulares neste processo, ainda não existe consenso entre os estudiosos da área. OBJETIVO: Verificar se existe diferença na conforma...

Juliane Tuma; Osíris Oliveira Camponês do Brasil; Paulo Augusto de Lima Pontes; Reinaldo Kasuo Yasaki

2005-01-01

314

The role of cervical and ocular vestibular-evoked myogenic potentials in the follow-up of vestibular neuritis.  

Science.gov (United States)

This study evaluates the recovery of vestibular nerve function after vestibular neuritis (VN) by vestibular-evoked myogenic potentials (VEMPs). Twenty-six patients with the diagnosis of VN were included. All patients underwent ocular VEMP (oVEMP) and cervical VEMP (cVEMP) recordings, at 6 days and 6 months from the onset of the symptoms. Of the 26 patients, 14 showed improvement on oVEMP at month 6 (group 1), and 12 showed no change or worsening on oVEMP at 6 months (group 2). At the same time, there was no change in the amplitudes of the cVEMP on either healthy or affected sides in both groups. Inability to perform the Fukuda test, and chronic white matter supratentorial lesions present on brain magnetic resonance imaging (MRI) were more frequent in patients with worse outcome on oVEMP (P = 0.044 and 0.045, respectively). Although involvement of the inferior branch of the vestibular nerve was not associated with oVEMP outcome, oVEMP latencies (N10 and P13) were associated with improvement or worsening in oVEMP amplitudes, showing that prolonged latencies correlate with 6-month improvement in oVEMP amplitudes (Pearson correlation -0.472, P = 0.041 and -0.580, P = 0.009, respectively). This study identified clinical, MRI and neurophysiological predictors of recovery in patients with superior VN, and offers additional insight into, and better understanding of, the role of VEMP in diagnosis and prognosis of patients with VN. Further studies are needed to validate this diagnostic procedure and to assess its clinical usefulness in VN management. PMID:23666957

Adamec, Ivan; Skori?, Magdalena Krbot; Handži?, Jadranka; Baruši?, Anabella Karla; Bach, Ivo; Gabeli?, Tereza; Habek, Mario

2014-04-01

315

The differential effects of acute right- vs. left-sided vestibular failure on brain metabolism.  

Science.gov (United States)

The human vestibular system is represented in the brain bilaterally, but it has functional asymmetries, i.e., a dominance of ipsilateral pathways and of the right hemisphere in right-handers. To determine if acute right- or left-sided unilateral vestibular neuritis (VN) is associated with differential patterns of brain metabolism in areas representing the vestibular network and the visual-vestibular interaction, patients with acute VN (right n = 9; left n = 13) underwent resting state (18)F-FDG PET once in the acute phase and once 3 months later after central vestibular compensation. The contrast acute vs. chronic phase showed signal differences in contralateral vestibular areas and the inverse contrast in visual cortex areas, both more pronounced in VN right. In VN left additional regions were found in the cerebellar hemispheres and vermis bilaterally, accentuated in severe cases. In general, signal changes appeared more pronounced in patients with more severe vestibular deficits. Acute phase PET data of patients compared to that of age-matched healthy controls disclosed similarities to these patterns, thus permitting the interpretation that the signal changes in vestibular temporo-parietal areas reflect signal increases, and in visual areas, signal decreases. These data imply that brain activity in the acute phase of right- and left-sided VN exhibits different compensatory patterns, i.e., the dominant ascending input is shifted from the ipsilateral to the contralateral pathways, presumably due to the missing ipsilateral vestibular input. The visual-vestibular interaction patterns were preserved, but were of different prominence in each hemisphere and more pronounced in patients with right-sided failure and more severe vestibular deficits. PMID:23686397

Becker-Bense, Sandra; Dieterich, Marianne; Buchholz, Hans-Georg; Bartenstein, Peter; Schreckenberger, Mathias; Brandt, Thomas

2014-07-01

316

Valor clínico dos nistagmos posicional e de posicionamento no diagnóstico vestibular de idosos / Clinical features of the positional nystagmus and the positioning nystagmus on vestibular diagnosis in elderly  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese OBJETIVO: estudar a importância da pesquisa do nistagmo posicional e de posicionamento na avaliação vestibular em idosos. MÉTODO: estudo retrospectivo e descritivo. Foram analisados 70 prontuários de pacientes com idade superior a 60 anos submetidos à avaliação vestibular, divididos em dois grupos: [...] grupo A composto por 35 prontuários com resultados da avaliação do nistagmo posicional e diagnóstico vestibular e grupo B composto por 35 prontuários com resultados da avaliação do nistagmo de posicionamento e diagnóstico vestibular. RESULTADOS: a pesquisa do nistagmo de posição destacou uma parcela significante de disfunção vestibular periférica no Grupo A e a pesquisa do nistagmo de posicionamento um número expressivo de vertigem posicional no Grupo B, que, ainda, apresentou prevalência de resultados normais. Não foram encontradas diferenças significantes entre os dois grupos para as variáveis, gênero e idade. CONCLUSÃO: a pesquisa do nistagmo de posição auxiliou na identificação de alterações vestibulares periféricas e a de posicionamento identificou a vertigem posicional, revelando que a introdução deste último parâmetro de avaliação foi positiva, porém não substitui o a pesquisa do nistagmo de posição. Abstract in english PURPOSE: to study the importance of positional nystagmus and positioning in vestibular assessment in the elderly. METHOD: retrospective descriptive study. It was analyzed evaluation charts of 70 patients aged over 60 years submitted of vestibular assessment. These charts were divided into two groups [...] : group A composed of 35 charts with evaluation results of the positional nystagmus and vestibular diagnosis and group B with 35 charts with the results of the evaluation positional nystagmus and vestibular diagnosis. RESULTS: nystagmus position highlighted a significant number of peripheral vestibular dysfunction in Group A and nystagmus positioning a large number of positional vertigo in Group B, in which, also, was founded a prevalence of normal results. No significant differences it was found between the two groups for the variables, gender and age. CONCLUSION: the nystagmus position test allowed identifying peripheral vestibular disorders and positioning nystagmus to identify positional vertigo, pointing that the introduction of the latter test was useful but not replace the nystagmus position evaluation.

Carlos Kazuo, Taguchi; Lucas Vieira, Alves; Rafael Oliveira, Gois; Priscila Feliciano, Oliveira.

2013-08-01

317

Reabilitação vestibular em pacientes idosos portadores de vertigem posicional paroxística benigna / Vestibular rehabilitation in elderly patients with benign paroxysmal positional vertigo  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A Vertigem Posicional Paroxística Benigna (VPPB) é um distúrbio vestibular no qual os pacientes relatam breves momentos de vertigem e/ou leve instabilidade postural, ocasionados por uma mudança brusca na movimentação cefálica ou corporal. OBJETIVO: Verificar o benefício da reabilitação vestibular, r [...] ealizada em grupo, em pacientes idosos portadores de VPPB. FORMA DE ESTUDO: Clínico prospectivo. MATERIAL E MÉTODO: Foram selecionados aleatoriamente 16 pacientes portadores de VPPB, todos medicados com extrato de Gingko-biloba (40mg de 12/12h) durante 30 dias. Oito deles, que formaram o Grupo Experimental, além do medicamento, foram submetidos à reabilitação vestibular e oito compuseram o Grupo Controle que não realizaram nenhum tipo de exercício. Para avaliação do benefício aplicamos a Escala de Atividades de Vida Diária e Desordens Vestibulares proposta por Cohen e Kimball. Para a análise estatística utilizamos o teste t-student. CONCLUSÃO: Nossos resultados apontaram benefício promovido pela reabilitação vestibular em grupo no tratamento de idosos portadores de VPPB; a avaliação qualitativa mostrou-se instrumento importante para a avaliação de benefício para o tratamento proposto; e a reabilitação vestibular em grupo mostrou ser uma excelente estratégia terapêutica. Abstract in english The Benign Paroxysmal Positional Vertigo (BPPV) is a vestibular disorder where the patients complain brief moments of vertigo and/or present postural instability, caused by a brusque change in the cephalic or body movement. AIM: The objective of the present study is certificate the benefit of the ve [...] stibular rehabilitation in elderly people with Benign Paroxysmal Positional Vertigo. STUDY DESIGN: Clinical prospective. MATERIAL AND METHOD: Sixteen patients with BPPV were thread with extract of Ginkgo-biloba (40mg of 12/12h) during 30 days. Eight patients (the Experimental Group) were submitted to vestibular rehabilitation and the other called Control Group, didn't perform any kind of exercises. In order to perform the evaluation of the benefit we used the Scale of Activity of Daily Life and Vestibular Disorders by Kohen and Kimball, and used the t-student test to statistical analysis. CONCLUSION: The vestibular rehabilitation in group showed benefit in the treatment in the Experimental Group; the Scale of Activity of Daily Life and Vestibular Disorders, was an important tool for the qualitative evaluation in our rehabilitation proposal and the vestibular rehabilitation in group showed as an excellent therapeutic strategy.

Carolina R., Resende; Carlos K., Taguchi; Juliane G. de, Almeida; Reginaldo R., Fujita.

2003-08-01

318

Reabilitação vestibular em pacientes idosos portadores de vertigem posicional paroxística benigna / Vestibular rehabilitation in elderly patients with benign paroxysmal positional vertigo  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A Vertigem Posicional Paroxística Benigna (VPPB) é um distúrbio vestibular no qual os pacientes relatam breves momentos de vertigem e/ou leve instabilidade postural, ocasionados por uma mudança brusca na movimentação cefálica ou corporal. OBJETIVO: Verificar o benefício da reabilitação vestibular, r [...] ealizada em grupo, em pacientes idosos portadores de VPPB. FORMA DE ESTUDO: Clínico prospectivo. MATERIAL E MÉTODO: Foram selecionados aleatoriamente 16 pacientes portadores de VPPB, todos medicados com extrato de Gingko-biloba (40mg de 12/12h) durante 30 dias. Oito deles, que formaram o Grupo Experimental, além do medicamento, foram submetidos à reabilitação vestibular e oito compuseram o Grupo Controle que não realizaram nenhum tipo de exercício. Para avaliação do benefício aplicamos a Escala de Atividades de Vida Diária e Desordens Vestibulares proposta por Cohen e Kimball. Para a análise estatística utilizamos o teste t-student. CONCLUSÃO: Nossos resultados apontaram benefício promovido pela reabilitação vestibular em grupo no tratamento de idosos portadores de VPPB; a avaliação qualitativa mostrou-se instrumento importante para a avaliação de benefício para o tratamento proposto; e a reabilitação vestibular em grupo mostrou ser uma excelente estratégia terapêutica. Abstract in english The Benign Paroxysmal Positional Vertigo (BPPV) is a vestibular disorder where the patients complain brief moments of vertigo and/or present postural instability, caused by a brusque change in the cephalic or body movement. AIM: The objective of the present study is certificate the benefit of the ve [...] stibular rehabilitation in elderly people with Benign Paroxysmal Positional Vertigo. STUDY DESIGN: Clinical prospective. MATERIAL AND METHOD: Sixteen patients with BPPV were thread with extract of Ginkgo-biloba (40mg of 12/12h) during 30 days. Eight patients (the Experimental Group) were submitted to vestibular rehabilitation and the other called Control Group, didn't perform any kind of exercises. In order to perform the evaluation of the benefit we used the Scale of Activity of Daily Life and Vestibular Disorders by Kohen and Kimball, and used the t-student test to statistical analysis. CONCLUSION: The vestibular rehabilitation in group showed benefit in the treatment in the Experimental Group; the Scale of Activity of Daily Life and Vestibular Disorders, was an important tool for the qualitative evaluation in our rehabilitation proposal and the vestibular rehabilitation in group showed as an excellent therapeutic strategy.

Carolina R., Resende; Carlos K., Taguchi; Juliane G. de, Almeida; Reginaldo R., Fujita.

319

Multisensory origin of the subjective first-person perspective: visual, tactile, and vestibular mechanisms.  

Science.gov (United States)

In three experiments we investigated the effects of visuo-tactile and visuo-vestibular conflict about the direction of gravity on three aspects of bodily self-consciousness: self-identification, self-location, and the experienced direction of the first-person perspective. Robotic visuo-tactile stimulation was administered to 78 participants in three experiments. Additionally, we presented participants with a virtual body as seen from an elevated and downward-directed perspective while they were lying supine and were therefore receiving vestibular and postural cues about an upward-directed perspective. Under these conditions, we studied the effects of different degrees of visuo-vestibular conflict, repeated measurements during illusion induction, and the relationship to a classical measure of visuo-vestibular integration. Extending earlier findings on experimentally induced changes in bodily self-consciousness, we show that self-identification does not depend on the experienced direction of the first-person perspective, whereas self-location does. Changes in bodily self-consciousness depend on visual gravitational signals. Individual differences in the experienced direction of first-person perspective correlated with individual differences in visuo-vestibular integration. Our data reveal important contributions of visuo-vestibular gravitational cues to bodily self-consciousness. In particular we show that the experienced direction of the first-person perspective depends on the integration of visual, vestibular, and tactile signals, as well as on individual differences in idiosyncratic visuo-vestibular strategies. PMID:23630611

Pfeiffer, Christian; Lopez, Christophe; Schmutz, Valentin; Duenas, Julio Angel; Martuzzi, Roberto; Blanke, Olaf

2013-01-01