Distribution of efferent cholinergic terminals and alpha-bungarotoxin binding to putative nicotinic acetylcholine receptors in the human vestibular end-organs.

PubMed

Ishiyama, A; Lopez, I; Wackym, P A

1995-11-01

Although acetylcholine (ACh) has been identified as the primary neurotransmitter of the efferent vestibular system in most animals studied, no direct evidence exists that ACh is the efferent neurotransmitter of the human vestibular system. Choline acetyltransferase immunohistochemistry (ChATi), acetylcholinesterase (AChE) histochemistry, and alpha-bungarotoxin binding were used in human vestibular end-organs to address this question. ChATi and AChE activity was found in numerous bouton-type terminals contacting the basal area of type II vestibular hair cells and the afferent chalices surrounding type I hair cells; alpha-bungarotoxin binding suggested the presence of nicotinic acetylcholine receptors on type II vestibular hair cells and on the afferent chalices surrounding type I hair cells. This study provides evidence that the human efferent vestibular axons and terminals are cholinergic and that the receptors receiving this innervation may be nicotinic.

Otolith-Canal Convergence in Vestibular Nuclei Neurons

NASA Technical Reports Server (NTRS)

Dickman, J. David

1996-01-01

During manned spaceflight, acute vestibular disturbances often occur, leading to physical duress and a loss of performance. Vestibular adaptation to the weightless environment follows within two to three days yet the mechanisms responsible for the disturbance and subsequent adaptation are still unknown In order to understand vestibular system function in space and normal earth conditions the basic physiological mechanisms of vestibular information co coding must be determined. Information processing regarding head movement and head position with respect to gravity takes place in the vestibular nuclei neurons that receive signals From the semicircular canals and otolith organs in the vestibular labyrinth. These neurons must synthesize the information into a coded output signal that provides for the head and eye movement reflexes as well as the conscious perception of the body in three-dimensional space The current investigation will for the first time. determine how the vestibular nuclei neurons quantitatively synthesize afferent information from the different linear and angular acceleration receptors in the vestibular labyrinths into an integrated output signal. During the second year of funding, progress on the current project has been focused on the anatomical orientation of semicircular canals and the spatial orientation of the innervating afferent responses. This information is necessary in order to understand how vestibular nuclei neurons process the incoming afferent spatial signals particularly with the convergent otolith afferent signals that are also spatially distributed Since information from the vestibular nuclei is presented to different brain regions associated with differing reflexive and sensory functions it is important to understand the computational mechanisms used by vestibular neurons to produce the appropriate output signal.

Vestibular recruitment

NASA Technical Reports Server (NTRS)

Tsemakhov, S. G.

1980-01-01

Vestibular recruitment is defined through the analysis of several references. It is concluded that vestibular recruitment is an objective phenomenon which manifests itself during the affection of the vestibular receptor and thus serves as a diagnostic tool during affection of the vestibular system.

Does the surgical approach in cochlear implantation influence the occurrence of postoperative vertigo?

PubMed

Todt, Ingo; Basta, Dietmar; Ernst, Arne

2008-01-01

To investigate the impact of different cochleostomy techniques on vestibular receptor integrity and vertigo after cochlear implantation. Retrospective cohort study. A total of 62 patients (17 to 84 years of age) underwent implantation via an anterior or round window insertion approach. Two groups of cochlear implant patients were compared with respect to their pre- and postoperative vestibular function and the occurrence of postoperative vertigo. The data were related to the different cochleostomy techniques. The patients were tested by a questionnaire (dizziness handicap inventory, DIH), caloric irrigation (vestibulo-ocular reflex, VOR) for the function of the lateral SCC and by vestibular evoked myogenic potential (VEMP) recordings for saccular function. Significant differences of postoperative VEMP responses (50% vs 13%) and electromystagmography (ENG) results (42.9% vs 9.4%) were found with respect to the 2 different insertion techniques. The number of patients with vertigo after the surgery as evidenced by DHI (23% vs 12.5%) was significantly different. The used round window approach for electrode insertion should be preferred to decrease the risk of loss of vestibular function and the occurrence of vertigo.

Effects of 17beta-estradiol on glutamate synaptic transmission and neuronal excitability in the rat medial vestibular nuclei.

PubMed

Grassi, S; Frondaroli, A; Scarduzio, M; Dutia, M B; Dieni, C; Pettorossi, V E

2010-02-17

We investigated the effects of the neurosteroid 17beta-estradiol (E(2)) on the evoked and spontaneous activity of rat medial vestibular nucleus (MVN) neurons in brainstem slices. E(2) enhances the synaptic response to vestibular nerve stimulation in type B neurons and depresses the spontaneous discharge in both type A and B neurons. The amplitude of the field potential, as well as the excitatory post-synaptic potential (EPSP) and current (EPSC), in type B neurons, are enhanced by E(2). Both effects are long-term phenomena since they outlast the drug washout. The enhancement of synaptic response is mainly due to facilitation of glutamate release mediated by pre-synaptic N-methyl-D-aspartate receptors (NMDARs), since the reduction of paired pulse ratio (PPR) and the increase of miniature EPSC frequency after E(2) are abolished under D-(-)-2-amino-5-phosphonopentanoic acid (AP-5). E(2) also facilitates post-synaptic NMDARs, but it does not affect directly alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) and group I-metabotropic glutamate receptors (mGluRs-I). In contrast, the depression of the spontaneous discharge of type A and type B neurons appears to depend on E(2) modulation of intrinsic ion conductances, as the effect remains after blockade of glutamate, GABA and glycine receptors (GlyRs). The net effect of E(2) is to enhance the signal-to-noise ratio of the synaptic response in type B neurons, relative to resting activity of all MVN neurons. These findings provide evidence for a novel potential mechanism to modulate the responsiveness of vestibular neurons to afferent inputs, and so regulate vestibular function in vivo.

Effects of Weightlessness on Vestibular Development: Summary of Research on NIH.R1

NASA Technical Reports Server (NTRS)

Fritzsch, Bernd; Bruce, L. L.

1998-01-01

In our original application we proposed to investigate the effects of gravity on the formation of connections between the gravity receptors of the ear and the brain in rat pups raised in space beginning at an age before these connections are made until near the time of birth, when they are to some extent functional. We used the neuronal tracer, Dil, which could be applied to tissue obtained immediately after landing of the space shuttle, thus minimizing changes due to the earth's gravity. We hoped to determine whether the vestibular system develops in two phases, as do other sensory systems (such as the visual system). In these other systems the first phase of development is controlled genetically and the second phase is controlled by environmental stimulation. Our data collected strongly supports the idea that the vestibular system has these same two phases of development. The tissue obtained from the NIH.R1 experiment was of exceptionally high quality for our analysis. Therefore, we expanded our investigation into the ultrastructural effects of microgravity on vestibular development. For the sake of clarity we will subdivide our summary into two categories: (1) analysis of the branching pattern of axons between the vestibular nerve and the gravistatic receptors of the ear in flight and control animals, and (2) analysis of the branching pattern of axons between the vestibular nerve and the brain in flight and control animals.

Effects of Weightlessness on Vestibular Development of Quail

NASA Technical Reports Server (NTRS)

Fritzsch, Bernd; Bruce, Laura L.

1997-01-01

The lack of gravity is known to alter vestibular responses in developing and adult vertebrates. One cause of these altered responses may be changes in the connections between the vestibular receptor and the brain. Therefore we propose to investigate the effects of gravity on the formations of connections between the gravity receptors of the ear and the brain in developing quail incubated in space beginning at an age before these connections are established (incubation day three) until near the time of hatching, when they are to some extent functional. This investigation will make use of a novel technique, the diffusion of a lipophilic dye, DiI, in fixed tissue. This technique can thus be used to analyze the connections in specimens fixed in orbit, thus eliminating changes due to the earth's gravity. The evaluation of the data will enable us to detect gross deviations from normal patterns as well as detailed quantitative deviations.

Results of the study of the vestibular apparatus and the functions of the perception of space in cosmonauts (pre- and post-flight observations)

NASA Technical Reports Server (NTRS)

Yakovleva, I. Y.; Kornilova, L. N.; Tarasov, I. K.; Alekseyev, V. N.

1980-01-01

The effect of the set of space flight factors caused a change in the activity of the vestibular apparatus and the spatial perception function. More significant and longer shifts were observed during expeditions of great duration. The detected disorders (increase in reactivity of the otolithic apparatus, decrease in sensitivity of the cupula receptor, deterioration in the perception accuracy, etc.) had a definite tendency to be restored. The primary damage to the otolithic reflex (changes were found in practically all the subjects) is probably caused by the specific effect of zero gravitation, and apparently, may be one of the trigger mechanisms for discrepancy in the activity of the sensory systems, disorders in the correcting function of the cerebellum, and central vestibular formations.

Bioelectrical activity of limb muscles during cold shivering of stimulation of the vestibular apparatus

NASA Technical Reports Server (NTRS)

Kuzmina, G. I.

1980-01-01

The effects of caloric and electric stimulation of the vestibular receptors on the EMG activity of limb muslces in anesthetized cats during cold induced shivering involved flexor muscles alone. Both types of stimulation suppressed bioelectrical activity more effectively in the ipsilateral muscles. The suppression of shivering activity seems to be due to the increased inhibitory effect of descending labyrinth pathways on the function of flexor motoneurons.

Otolith and Vertical Canal Contributions to Dynamic Postural Control

NASA Technical Reports Server (NTRS)

Black, F. Owen

1999-01-01

The objective of this project is to determine: 1) how do normal subjects adjust postural movements in response to changing or altered otolith input, for example, due to aging? and 2) how do patients adapt postural control after altered unilateral or bilateral vestibular sensory inputs such as ablative inner ear surgery or ototoxicity, respectively? The following hypotheses are under investigation: 1) selective alteration of otolith input or abnormalities of otolith receptor function will result in distinctive spatial, frequency, and temporal patterns of head movements and body postural sway dynamics. 2) subjects with reduced, altered, or absent vertical semicircular canal receptor sensitivity but normal otolith receptor function or vice versa, should show predictable alterations of body and head movement strategies essential for the control of postural sway and movement. The effect of altered postural movement control upon compensation and/or adaptation will be determined. These experiments provide data for the development of computational models of postural control in normals, vestibular deficient subjects and normal humans exposed to unusual force environments, including orbital space flight.

Astronaut Owen Garriott - Test Subject - Human Vestibular Function Experiment

NASA Image and Video Library

1973-08-09

S73-34171 (9 Aug. 1973) --- Scientist-astronaut Owen K. Garriott, Skylab 3 science pilot, serves as test subject for the Skylab ?Human Vestibular Function? M131 Experiment, as seen in this photographic reproduction taken from a television transmission made by a color TV camera aboard the Skylab space station in Earth orbit. The objectives of the Skylab M131 experiment are to obtain data pertinent to establishing the validity of measurements of specific behavioral/physiological responses influenced by vestibular activity under one-g and zero-g conditions; to determine man?s adaptability to unusual vestibular conditions and predict habitability of future spacecraft conditions involving reduced gravity and Coriollis forces; and to measure the accuracy and variability in man?s judgment of spatial coordinates based on atypical gravity receptor cues and inadequate visual cures. Dr. Garriott is seated in the experiment?s litter chair which can rotate the test subject at predetermined rotational velocity or programmed acceleration/decelerational profile. Photo credit: NASA

Role of the vestibular nuclei in endothelin-1-induced barrel rotation in rats.

PubMed

Kozako, Tomohiro; Kawachi, Akio; Cheng, Shi-Bin; Kuchiiwa, Satoshi; Motoya, Toshiro; Nakagawa, Shiro; Yamada, Katsushi

2002-11-15

The fourth or lateral ventricular injection of endothelin-1 resulted in a dose-dependent increase in the barrel rotation and produced marked induction of c-Fos-positive cells in the vestibular nuclei. The doses of the former injection were lower and had shorter mean latent periods compared with the later injection. c-Fos expression after endothelin-1 injection was prevented by the pretreatment with the endothelin ET(A) receptor antagonist, cyclo(D-alpha-aspartyl-L-propyl-D-valyl-L-leucyl-D-tryptophyl) (BQ-123), the glutamate NMDA receptor antagonist, dizocilpine maleate (MK-801), or the L-type Ca(2+) channel antagonist, verapamil, in addition to the incidence of the rotational behavior. There was a significant difference in c-Fos expression between the right and left medial vestibular nuclei, and the number of c-Fos-labeled neurons in the medial vestibular nucleus was markedly increased on the opposite side of the rotational direction. These results suggest that the elicitation of the barrel rotation may be mediated by endothelin ET(A) receptors, glutamate NMDA receptors, and L-type Ca(2+) channels. The changes in the receptor and channel systems induced by endothelin-1 injections appeared to exert crucial influences on the vestibular nuclei and then on the maintenance of equilibrium. The direction of the barrel rotation has a deep connection with the imbalance of neuronal activity in the left and right medial vestibular nuclei.

[Study of the structure of receptor organs of the vestibular apparatus of rats after space flight on "Kosmos-1667"].

PubMed

Lychakov, D V; Pashchinin, A N; Boiadzhieva-Mikhaĭlova, A; Khristov, I

1989-01-01

The receptor organs of the vestibular apparatus of rats flown for 7 days on Cosmos-1667 were examined. Serial sections were examined by light microscopy, some utriculus sections by electron microscopy, and otolith membranes by scanning electron microscopy. The fixation method used revealed a distinct structural heterogeneity of the receptor epithelium. In the striola area of the utriculus and sacculus as well as in the central apical area of cristae there are receptor cells surrounded by enlarged cup-like nerve endings. The nerve endings occupy over 70% of the cup-receptor cell complex. The area incorporating the enlarged nerve endings differs in size from animal to animal and from left to right ear in the same animal. The flown rat that was the first to be killed after recovery showed a very well pronounced asymmetry: in the right ear enlarged cups were seen all over the epithelium while in the left ear they were located in distinct spots. Since such changes were not identified in the remaining flown and control rats, it is concluded that they were produced by space flight effects but remained reversible and disappeared after recovery. This paper describes the causes responsible of the changes and their structural and functional relevances as well as other structural modifications that should be considered during vestibular studies.

Absence of Rotation Perception during Warm Water Caloric Irrigation in Some Seniors with Postural Instability.

PubMed

Chiarovano, Elodie; Vidal, Pierre-Paul; Magnani, Christophe; Lamas, Georges; Curthoys, Ian S; de Waele, Catherine

2016-01-01

Falls in seniors are a major public health problem. Falls lead to fear of falling, reduced mobility, and decreased quality of life. Vestibular dysfunction is one of the fall risk factors. The relationship between objective measures of vestibular responses and age has been studied. However, the effects of age on vestibular perception during caloric stimulation have not been studied. Twenty senior subjects were included in the study, and separated in two groups: 10 seniors reporting postural instability (PI) and exhibiting absence of vestibular perception when they tested with caloric stimulation and 10 sex- and age-matched seniors with no such problems (controls). We assessed vestibular perception on a binary rating scale during the warm irrigation of the caloric test. The function of the various vestibular receptors was assessed using video head impulse test (vHIT), caloric tests, and cervical and ocular vestibular-evoked myogenic potentials. The Equitest was used to evaluate balance. No horizontal canal dysfunction assessed using both caloric test and vHIT was detected in either group. No significant difference was detected between PI and control groups for the peak SPV of caloric-induced ocular nystagmus or for the HVOR gain. All the controls perceived rotation when the maximal SPV during warm irrigation was equal to or ≥15°/s. None of the subjects in the PI group perceived rotation even while the peak SPV exceeded 15°/s, providing objective evidence of normal peripheral horizontal canal function. All the PI group had abnormal Equitest results, particularly in the two last conditions. These investigations show for the first time that vestibular perception can be absent during a caloric test despite normal horizontal canal function. We call this as dissociation vestibular neglect. Patients with poor vestibular perception may not be aware of postural perturbations and so will not correct for them. Thus, falls in the elderly may result, among other factors, from a vestibular neglect due to an inappropriate central processing of normal vestibular peripheral inputs. That is, failure to perceive rotation during caloric testing when the SPV is >15°/s, should prompt the clinician to envisage preventive actions to avoid future falls such as rehabilitation.

Compound gravity receptor polarization vectors evidenced by linear vestibular evoked potentials

NASA Technical Reports Server (NTRS)

Jones, S. M.; Jones, T. A.; Bell, P. L.; Taylor, M. J.

2001-01-01

The utricle and saccule are gravity receptor organs of the vestibular system. These receptors rely on a high-density otoconial membrane to detect linear acceleration and the position of the cranium relative to Earth's gravitational vector. The linear vestibular evoked potential (VsEP) has been shown to be an effective non-invasive functional test specifically for otoconial gravity receptors (Jones et al., 1999). Moreover, there is some evidence that the VsEP can be used to independently test utricular and saccular function (Taylor et al., 1997; Jones et al., 1998). Here we characterize compound macular polarization vectors for the utricle and saccule in hatchling chickens. Pulsed linear acceleration stimuli were presented in two axes, the dorsoventral (DV, +/- Z axis) to isolate the saccule, and the interaural (IA, +/- Y axis) to isolate the utricle. Traditional signal averaging was used to resolve responses recorded from the surface of the skull. Latency and amplitude of eighth nerve components of the linear VsEP were measured. Gravity receptor responses exhibited clear preferences for one stimulus direction in each axis. With respect to each utricular macula, lateral translation in the IA axis produced maximum ipsilateral response amplitudes with substantially greater amplitude intensity (AI) slopes than medially directed movement. Downward caudal motions in the DV axis produced substantially larger response amplitudes and AI slopes. The results show that the macula lagena does not contribute to the VsEP compound polarization vectors of the sacculus and utricle. The findings suggest further that preferred compound vectors for the utricle depend on the pars externa (i.e. lateral hair cell field) whereas for the saccule they depend on pars interna (i.e. superior hair cell fields). These data provide evidence that maculae saccule and utricle can be selectively evaluated using the linear VsEP.

Modification of tenascin-R expression following unilateral labyrinthectomy in rats indicates its possible role in neural plasticity of the vestibular neural circuit.

PubMed

Gaal, Botond; Jóhannesson, Einar Örn; Dattani, Amit; Magyar, Agnes; Wéber, Ildikó; Matesz, Clara

2015-09-01

We have previously found that unilateral labyrinthectomy is accompanied by modification of hyaluronan and chondroitin sulfate proteoglycan staining in the lateral vestibular nucleus of rats and the time course of subsequent reorganization of extracellular matrix assembly correlates to the restoration of impaired vestibular function. The tenascin-R has repelling effect on pathfinding during axonal growth/regrowth, and thus inhibits neural circuit repair. By using immunohistochemical method, we studied the modification of tenascin-R expression in the superior, medial, lateral, and descending vestibular nuclei of the rat following unilateral labyrinthectomy. On postoperative day 1, tenascin-R reaction in the perineuronal nets disappeared on the side of labyrinthectomy in the superior, lateral, medial, and rostral part of the descending vestibular nuclei. On survival day 3, the staining intensity of tenascin-R reaction in perineuronal nets recovered on the operated side of the medial vestibular nucleus, whereas it was restored by the time of postoperative day 7 in the superior, lateral and rostral part of the descending vestibular nuclei. The staining intensity of tenascin-R reaction remained unchanged in the caudal part of the descending vestibular nucleus bilaterally. Regional differences in the modification of tenascin-R expression presented here may be associated with different roles of individual vestibular nuclei in the compensatory processes. The decreased expression of the tenascin-R may suggest the extracellular facilitation of plastic modifications in the vestibular neural circuit after lesion of the labyrinthine receptors.

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

NASA Technical Reports Server (NTRS)

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

2000-01-01

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.

Central adaptation to repeated galvanic vestibular stimulation: implications for pre-flight astronaut training.

PubMed

Dilda, Valentina; Morris, Tiffany R; Yungher, Don A; MacDougall, Hamish G; Moore, Steven T

2014-01-01

Healthy subjects (N = 10) were exposed to 10-min cumulative pseudorandom bilateral bipolar Galvanic vestibular stimulation (GVS) on a weekly basis for 12 weeks (120 min total exposure). During each trial subjects performed computerized dynamic posturography and eye movements were measured using digital video-oculography. Follow up tests were conducted 6 weeks and 6 months after the 12-week adaptation period. Postural performance was significantly impaired during GVS at first exposure, but recovered to baseline over a period of 7-8 weeks (70-80 min GVS exposure). This postural recovery was maintained 6 months after adaptation. In contrast, the roll vestibulo-ocular reflex response to GVS was not attenuated by repeated exposure. This suggests that GVS adaptation did not occur at the vestibular end-organs or involve changes in low-level (brainstem-mediated) vestibulo-ocular or vestibulo-spinal reflexes. Faced with unreliable vestibular input, the cerebellum reweighted sensory input to emphasize veridical extra-vestibular information, such as somatosensation, vision and visceral stretch receptors, to regain postural function. After a period of recovery subjects exhibited dual adaption and the ability to rapidly switch between the perturbed (GVS) and natural vestibular state for up to 6 months.

Otoconin-90 deletion leads to imbalance but normal hearing: a comparison with other otoconia mutants.

PubMed

Zhao, X; Jones, S M; Yamoah, E N; Lundberg, Y Wang

2008-04-22

Our sense of gravitation and linear acceleration is mediated by stimulation of vestibular hair cells through displacement of otoconia in the utricle and saccule (the gravity receptor organ). We recently showed that otoconin-90 (Oc90) deletion led to formation of giant otoconia. In the present study, we determined the extent to which the giant otoconia affected balance and gravity receptor sensory input and compared the findings with other otoconia mutants. We employed a wide spectrum of balance behavioral tests, including reaching and air-righting reflexes, gait, swimming, beam-crossing, rotorod latencies, and a direct measure of gravity receptor input, vestibular evoked potentials (VsEPs). All tests on homozygous adult mutants consistently ranked the order of imbalance as (from worst to best) Nox3(het)

Personality traits modulate subcortical and cortical vestibular and anxiety responses to sound-evoked otolithic receptor stimulation.

PubMed

Indovina, Iole; Riccelli, Roberta; Staab, Jeffrey P; Lacquaniti, Francesco; Passamonti, Luca

2014-11-01

Strong links between anxiety, space-motion perception, and vestibular symptoms have been recognized for decades. These connections may extend to anxiety-related personality traits. Psychophysical studies showed that high trait anxiety affected postural control and visual scanning strategies under stress. Neuroticism and introversion were identified as risk factors for chronic subjective dizziness (CSD), a common psychosomatic syndrome. This study examined possible relationships between personality traits and activity in brain vestibular networks for the first time using functional magnetic resonance imaging (fMRI). Twenty-six right-handed healthy individuals underwent fMRI during sound-evoked vestibular stimulation. Regional brain activity and functional connectivity measures were correlated with personality traits of the Five Factor Model (neuroticism, extraversion-introversion, openness, agreeableness, consciousness). Neuroticism correlated positively with activity in the pons, vestibulo-cerebellum, and para-striate cortex, and negatively with activity in the supra-marginal gyrus. Neuroticism also correlated positively with connectivity between pons and amygdala, vestibulo-cerebellum and amygdala, inferior frontal gyrus and supra-marginal gyrus, and inferior frontal gyrus and para-striate cortex. Introversion correlated positively with amygdala activity and negatively with connectivity between amygdala and inferior frontal gyrus. Neuroticism and introversion correlated with activity and connectivity in cortical and subcortical vestibular, visual, and anxiety systems during vestibular stimulation. These personality-related changes in brain activity may represent neural correlates of threat sensitivity in posture and gaze control mechanisms in normal individuals. They also may reflect risk factors for anxiety-related morbidity in patients with vestibular disorders, including previously observed associations of neuroticism and introversion with CSD. Copyright © 2014 Elsevier Inc. All rights reserved.

NMDA receptor-mediated long term modulation of electrically evoked field potentials in the rat medial vestibular nuclei.

PubMed

Capocchi, G; Della Torre, G; Grassi, S; Pettorossi, V E; Zampolini, M

1992-01-01

The effect of high frequency stimulation (HFS) of the primary vestibular afferents on field potentials recorded in the ipsilateral Medial Vestibular Nuclei (MVN) was studied. Our results show that potentiation and depression can be induced in different portions of MVN, which are distinguishable by their anatomical organization. HFS induces potentiation of the monosynaptic component in the ventral portion of the MVN, whereas it provokes depression of the polysynaptic component in the dorsal portion of the same nucleus. The induction of both potentiation and depression was blocked under AP5 perfusion, thus demonstrating that NMDA receptor activation mediates both phenomena. Furthermore, the finding that the field potentials were not modified during perfusion with DL-AP5, as previously reported, supports the hypothesis that NMDA receptors are not involved in the normal synaptic transmission from the primary vestibular afferent fibres, but are only activated following hyperstimulation of this afferent system. Our results suggest that the mechanisms of long term modification of synaptic efficacy observed in MVN may underlie the plasticity phenomena occurring in vestibular nuclei.

Cholinergic agonists increase intracellular calcium concentration in frog vestibular hair cells.

PubMed

Ohtani, M; Devau, G; Lehouelleur, J; Sans, A

1994-11-01

Acetylcholine (ACh) is usually considered to be the neurotransmitter of the efferent vestibular system. The nature and the localization of cholinergic receptors have been investigated on frog isolated vestibular hair cells (VHCs), by measuring variations of intracellular calcium concentration ([Ca2+]i), using calcium sensitive dye fura-2. Focal iontophoretic ACh (1 M, 300 nA.40 ms) application induced a rapid increase in [Ca2+]i, reaching a peak in 20 s and representing about 5-fold the resting level (from 61 +/- 6 to 320 +/- 26 nM). Applications of muscarinic agonists as methacholine and carbachol induced weaker calcium responses (from 78 +/- 25 to 238 +/- 53 nM) than the one obtained with ACh applications. These muscarinic agonists were efficient only in precise zones. Desensitization of muscarinic receptors to successive stimulations was significant. Perfusion of nicotine or 1,1-dimethyl-4-phenyl-piperazinium (DMPP), a nicotinic agonist, induced an increase in [Ca2+]i only in some cells (4/28 with DMPP). These results indicated the presence of cholinergic receptors on frog VHCs: muscarinic receptors were more responsive than nicotinic receptors. Presence of muscarinic and nicotinic receptors in the membrane of VHCs could indicate different modulations of VHCs activity mediated by [Ca2+]i and involving an efferent control which represents a central regulation of the vestibular afferent message.

Saccular function in otosclerosis patients: bone conducted-vestibular evoked myogenic potential analysis.

PubMed

Amali, Amin; Mahdi, Parvane; Karimi Yazdi, Alireza; Khorsandi Ashtiyani, Mohammad Taghi; Yazdani, Nasrin; Vakili, Varasteh; Pourbakht, Akram

2014-01-01

Vestibular involvements have long been observed in otosclerotic patients. Among vestibular structures saccule has the closest anatomical proximity to the sclerotic foci, so it is the most prone vestibular structure to be affected during the otosclerosis process. The aim of this study was to investigate the saccular function in patients suffering from otosclerosis, by means of Vestibular Evoked Myogenic Potential (VEMP). The material consisted of 30 otosclerosis patients and 20 control subjects. All participants underwent audiometric and VEMP testing. Analysis of tests results revealed that the mean values of Air-Conducted Pure Tone Average (AC-PTA) and Bone-Conducted Pure Tone Average (BC-PTA) in patients were 45.28 ± 15.57 and 19.68 ± 10.91, respectively and calculated 4 frequencies Air Bone Gap (ABG) was 25.64 ± 9.95. The VEMP response was absent in 14 (28.57%) otosclerotic ears. A statistically significant increase in latency of the p13 was found in the affected ears (P=0.004), differences in n23 latency did not reach a statistically significant level (P=0.112). Disparities in amplitude of p13-n23 in between two study groups was statistically meaningful (P=0.009), indicating that the patients with otosclerosis had lower amplitudes. This study tends to suggest that due to the direct biotoxic effect of the materials released from the otosclerosis foci on saccular receptors, there might be a possibility of vestibular dysfunction in otosclerotic patients.

SKYLAB (SL)-3 - ASTRONAUT GARRIOTT, OWEN

NASA Image and Video Library

1973-08-09

S73-32113 (9 Aug. 1973) --- Scientist-astronaut Owen K. Garriott, Skylab 3 science pilot, serves as test subject for the Skylab ?Human Vestibular Function? M131 Experiment, as seen in this photographic reproduction taken from a television transmission made by a color TV camera aboard the Skylab space station in Earth orbit. The objectives of the Skylab M131 experiment are to obtain data pertinent to establishing the validity of measurements of specific behavioral/physiological responses influenced by vestibular activity under one-g and zero-g conditions; to determine man?s adaptability to unusual vestibular conditions and predict habitability of future spacecraft conditions involving reduced gravity and Coriollis forces; and to measure the accuracy and variability in man?s judgment of spatial coordinates based on atypical gravity receptor cues and inadequate visual cues. Photo credit: NASA

Responses of neurons in the caudal medullary lateral tegmental field to visceral inputs and vestibular stimulation in vertical planes

PubMed Central

Moy, Jennifer D.; Miller, Daniel J.; Catanzaro, Michael F.; Boyle, Bret M.; Ogburn, Sarah W.; Cotter, Lucy A.; McCall, Andrew A.

2012-01-01

The dorsolateral reticular formation of the caudal medulla, or the lateral tegmental field (LTF), has been classified as the brain's “vomiting center”, as well as an important region in regulating sympathetic outflow. We examined the responses of LTF neurons in cats to rotations of the body that activate vestibular receptors, as well as to stimulation of baroreceptors (through mechanical stretch of the carotid sinus) and gastrointestinal receptors (through the intragastric administration of the emetic compound copper sulfate). Approximately half of the LTF neurons exhibited graviceptive responses to vestibular stimulation, similar to primary afferents innervating otolith organs. The other half of the neurons had complex responses, including spatiotemporal convergence behavior, suggesting that they received convergent inputs from a variety of vestibular receptors. Neurons that received gastrointestinal and baroreceptor inputs had similar complex responses to vestibular stimulation; such responses are expected for neurons that contribute to the generation of motion sickness. LTF units with convergent baroreceptor and vestibular inputs may participate in producing the cardiovascular system components of motion sickness, such as the changes in skin blood flow that result in pallor. The administration of copper sulfate often modulated the gain of responses of LTF neurons to vestibular stimulation, particularly for units whose spontaneous firing rate was altered by infusion of drug (median of 459%). The present results raise the prospect that emetic signals from the gastrointestinal tract modify the processing of vestibular inputs by LTF neurons, thereby affecting the probability that vomiting will occur as a consequence of motion sickness. PMID:22955058

Role of group II metabotropic glutamate receptors 2/3 and group I metabotropic glutamate receptor 5 in developing rat medial vestibular nuclei.

PubMed

Grassi, Silvarosa; Frondaroli, Adele; Pettorossi, Vito Enrico

2005-08-22

In brainstem slices from developing rats, metabotropic glutamate receptors mGluR2/3 and mGluR5 play different inhibitory roles in synaptic transmission and plasticity of the medial vestibular nuclei. The mGluR2/3 block (LY341495) reduces the occurrence of long-term depression after vestibular afferent high frequency stimulation at P8-P10, and increases that of long-term potentiation, while the mGluR5 block prevents high frequency stimulation long-term depression. Later on, the receptor block does not influence high frequency stimulation effects. In addition, while mGluR2/3 agonist (APDC) always provokes a transient reduction of synaptic responses, that of mGluR5 (CHPG) induces long-term depression per se at P8-P10. These results show a key role of mGluR5 in inducing high frequency stimulation long-term depression in developing medial vestibular nuclei, while mGluR2/3 modulate synaptic transmission, probably through presynaptic control of glutamate release.

Platelet-activating factor and group I metabotropic glutamate receptors interact for full development and maintenance of long-term potentiation in the rat medial vestibular nuclei.

PubMed

Grassi, S; Francescangeli, E; Goracci, G; Pettorossi, V E

1999-01-01

In rat brainstem slices, we investigated the interaction between platelet-activating factor and group I metabotropic glutamate receptors in mediating long-term potentiation within the medial vestibular nuclei. We analysed the N1 field potential wave evoked in the ventral portion of the medial vestibular nuclei by primary vestibular afferent stimulation. The group I metabotropic glutamate receptor antagonist, (R,S)-1-aminoindan-1,5-dicarboxylic acid, prevented long-term potentiation induced by a platelet-activating factor analogue [1-O-hexadecyl-2-O-(methylcarbamyl)-sn-glycero-3-phosphocholine], as well as the full development of potentiation, induced by high-frequency stimulation under the blocking agent for synaptosomal platelet-activating factor receptors (ginkolide B), at drug washout. However, potentiation directly induced by the group I glutamate metabotropic receptor agonist, (R,S)-3,5-dihydroxyphenylglycine, was reduced by ginkolide B. These findings suggest that platelet-activating factor, whether exogenous or released following potentiation induction, exerts its effect through presynaptic group I metabotropic glutamate receptors, mediating the increase of glutamate release. In addition, we found that this mechanism, which led to full potentiation through presynaptic group I metabotropic glutamate receptor activation, was inactivated soon after application of potentiation-inducing stimulus. In fact, the long-lasting block of the platelet-activating factor and metabotropic glutamate receptors prevented the full potentiation development and the induced potentiation progressively declined to null. Moreover, ginkolide B, given when high-frequency-dependent potentiation was established, only reduced it within 5 min after potentiation induction. We conclude that to fully develop vestibular long-term potentiation requires presynaptic events. Platelet-activating factor, released after the activation of postsynaptic mechanisms which induce potentiation, is necessary for coupling postsynaptic and presynaptic phenomena, through the activation of group I metabotropic glutamate receptors, and its action lasts only for a short period. If this coupling does not occur, a full and long-lasting potentiation cannot develop.

The new vestibular stimuli: sound and vibration-anatomical, physiological and clinical evidence.

PubMed

Curthoys, Ian S

2017-04-01

The classical view of the otoliths-as flat plates of fairly uniform receptors activated by linear acceleration dragging on otoconia and so deflecting the receptor hair bundles-has been replaced by new anatomical and physiological evidence which shows that the maculae are much more complex. There is anatomical spatial differentiation across the macula in terms of receptor types, hair bundle heights, stiffness and attachment to the overlying otolithic membrane. This anatomical spatial differentiation corresponds to the neural spatial differentiation of response dynamics from the receptors and afferents from different regions of the otolithic maculae. Specifically, receptors in a specialized band of cells, the striola, are predominantly type I receptors, with short, stiff hair bundles and looser attachment to the overlying otoconial membrane than extrastriolar receptors. At the striola the hair bundles project into holes in the otolithic membrane, allowing for fluid displacement to deflect the hair bundles and activate the cell. This review shows the anatomical and physiological evidence supporting the hypothesis that fluid displacement, generated by sound or vibration, deflects the short stiff hair bundles of type I receptors at the striola, resulting in neural activation of the irregular afferents innervating them. So these afferents are activated by sound or vibration and show phase-locking to individual cycles of the sound or vibration stimulus up to frequencies above 2000 Hz, underpinning the use of sound and vibration for clinical tests of vestibular function.

Caspase inhibitors promote vestibular hair cell survival and function after aminoglycoside treatment in vivo

NASA Technical Reports Server (NTRS)

Matsui, Jonathan I.; Haque, Asim; Huss, David; Messana, Elizabeth P.; Alosi, Julie A.; Roberson, David W.; Cotanche, Douglas A.; Dickman, J. David; Warchol, Mark E.

2003-01-01

The sensory hair cells of the inner ear undergo apoptosis after acoustic trauma or aminoglycoside antibiotic treatment, causing permanent auditory and vestibular deficits in humans. Previous studies have demonstrated a role for caspase activation in hair cell death and ototoxic injury that can be reduced by concurrent treatment with caspase inhibitors in vitro. In this study, we examined the protective effects of caspase inhibition on hair cell death in vivo after systemic injections of aminoglycosides. In one series of experiments, chickens were implanted with osmotic pumps that administrated the pan-caspase inhibitor z-Val-Ala-Asp(Ome)-fluoromethylketone (zVAD) into inner ear fluids. One day after the surgery, the animals received a 5 d course of treatment with streptomycin, a vestibulotoxic aminoglycoside. Direct infusion of zVAD into the vestibule significantly increased hair cell survival after streptomycin treatment. A second series of experiments determined whether rescued hair cells could function as sensory receptors. Animals treated with streptomycin displayed vestibular system impairment as measured by a greatly reduced vestibulo-ocular response (VOR). In contrast, animals that received concurrent systemic administration of zVAD with streptomycin had both significantly greater hair cell survival and significantly increased VOR responses, as compared with animals treated with streptomycin alone. These findings suggest that inhibiting the activation of caspases promotes the survival of hair cells and protects against vestibular function deficits after aminoglycoside treatment.

Orbiting Frog Otolith experiment (OFO-A): Data reduction and control experimentation

NASA Technical Reports Server (NTRS)

Gualtierotti, T.; Bracchi, F.; Rocca, E.

1972-01-01

The OFO-A mission was prepared as a part of a special program of vestibular physiology with the purpose of studying in which way the lack of the gravity pull will affect the functioning of that part of the labyrinth which controls balance. The gravitational components corresponded to the different head positions, namely, the gravity sensitive or positioning receptors. It is evident that in weightlessness the gravity sensitive receptors are deprived of their primary input.

The chronic infusion of nicotine into the developing chick embryo does not alter the density of (-)-[3H]nicotine-binding sites or vestibular function

NASA Technical Reports Server (NTRS)

Roll, R. L.; Jones, T. A.; Benowitz, N. L.; Morley, B. J.

1993-01-01

(-)-Nicotine (1.2 mg/day) or saline was infused into chick embryos (Gallus domesticus) for 10 days beginning 12 h beyond the eight day of incubation (E8 + 12 h). Twelve h beyond the eighteenth day of incubation (E18 + 12 h), the eggs were opened to access the embryos and subcutaneous skull electrodes placed. Short latency vestibular response thresholds and input/output functions were determined to assess neurophysiological consequences of chronic nicotine administration. Samples of serum and extraembryonic (amniotic and albumen) fluid were analyzed by gas chromatography-mass spectrometry to determine the levels of nicotine and its major metabolite, cotinine. The brains were removed and divided into diencephalon and mesencephalon and the density of (-)-[3H]nicotine binding sites in each brain area was measured. Nicotine and cotinine were found in the serum and extraembryonic fluid, but nicotinic receptors were not up-regulated in the brains of animals infused with nicotine in comparison to controls. Vestibular response thresholds also did not differ between nicotine-treated and control animals.

Responses to vertical vestibular stimulation of neurons in the nucleus reticularis gigantocellularis in rabbits.

PubMed

Fagerson, M H; Barmack, N H

1995-06-01

1. Because the nucleus reticularis gigantocellularis (NRGc) receives a substantial descending projection from the caudal vestibular nuclei, we used extracellular single-unit recording combined with natural vestibular stimulation to examine the possible peripheral origins of the vestibularly modulated activity of caudal NRGc neurons located within 500 microns of the midline. Chloralose-urethan anesthetized rabbits were stimulated with an exponential "step" and/or static head-tilt stimulus, as well as sinusoidal rotation about the longitudinal or interaural axes providing various combinations of roll or pitch, respectively. Recording sites were reconstructed from electrolytic lesions confirmed histologically. 2. More than 85% of the 151 neurons, in the medial aspect of the caudal NRGc, responded to vertical vestibular stimulation. Ninety-six percent of these responded to rotation onto the contralateral side (beta responses). Only a few also responded to horizontal stimulation. Seventy-eight percent of the neurons that responded to vestibular stimulation responded during static roll-tilt. One-half of these neurons also responded transiently to the change in head position during exponential "step" stimulation, suggesting input mediated by otolith and semicircular canal receptors or tonic-phasic otolith neurons. 3. Seventy-five percent of the responsive neurons had a "null plane." The planes of stimulation resulting in maximal responses, for cells that responded to static stimulation, were distributed throughout 150 degrees in both roll and pitch quadrants. Five of these cells responded only transiently during exponential "step" stimulation and responded maximally when stimulated in the plane of one of the vertical semicircular canals. 4. The phase of the response of the 25% of medial NRGc neurons that lacked "null planes" gradually shifted approximately 180 degrees during sinusoidal vestibular stimulation as the plane of stimulation was shifted about the vertical axis. These neurons likely received convergent input with differing spatial and temporal properties. 5. The activity of neurons in the medial aspect of the caudal NRGc of rabbits was modulated by both otolithic macular and vertical semicircular canal receptor stimulation. This vestibular information may be important for controlling the intensity of the muscle activity in muscles such as neck muscles where the load on the muscle is affected by the position of the head with respect to gravity. Some of these neurons may also shift muscle function from an agonist to an antagonist as the direction of head tilt changes.

Entrainment and phase-shifting by centrifugation abolished in mice lacking functional vestibular input

NASA Astrophysics Data System (ADS)

Fuller, Charles; Ringgold, Kristyn

The circadian pacemaker can be phase shifted and entrained by appropriately timed locomotor activity, however the mechanism(s) involved remain poorly understood. Recent work in our lab has suggested the involvement of the vestibular otolith organs in activity-induced changes within the circadian timing system (CTS). For example, we have shown that changes in circa-dian period and phase in response to locomotion (wheel running) require functional macular gravity receptors. We believe the neurovestibular system is responsible for the transduction of gravitoinertial input associated with the types of locomotor activity that are known to af-fect the pacemaker. This study investigated the hypothesis that daily, timed gravitoinertial stimuli, as applied by centrifugation. would induce entrainment of circadian rhythms in only those animals with functional afferent vestibular input. To test this hypothesis, , chemically labyrinthectomized (Labx) mice, mice lacking macular vestibular input (head tilt or hets) and wildtype (WT) littermates were implanted i.p. with biotelemetry and individually housed in a 4-meter diameter centrifuge in constant darkness (DD). After 2 weeks in DD, the mice were exposed daily to 2G via centrifugation from 1000-1200 for 9 weeks. Only WT mice showed entrainment to the daily 2G pulse. The 2G pulse was then re-set to occur at 1200-1400 for 4 weeks. Only WT mice demonstrated a phase shift in response to the re-setting of the 2G pulse and subsequent re-entrainment to the new centrifugation schedule. These results provide further evidence that gravitoinertial stimuli require a functional vestibular system to both en-train and phase shift the CTS. Entrainment among only WT mice supports the role of macular gravity receptive cells in modulation of the CTS while also providing a functional mechanism by which gravitoinertial stimuli, including locomotor activity, may affect the pacemaker.

The muscarinic inhibition of the potassium M-current modulates the action-potential discharge in the vestibular primary-afferent neurons of the rat.

PubMed

Pérez, C; Limón, A; Vega, R; Soto, E

2009-02-18

There is consensus that muscarinic and nicotinic receptors expressed in vestibular hair cells and afferent neurons are involved in the efferent modulation of the electrical activity of the afferent neurons. However the underlying mechanisms of postsynaptic control in neurons are not well understood. In our work we show that the activation of muscarinic receptors in the vestibular neurons modulates the potassium M-current modifying the activity of afferent neurons. Whole-cell patch-clamp recordings were made on vestibular-afferent neurons isolated from Wistar rats (postnatal days 7-10) and held in primary culture (18-24 h). The M-current was studied during its deactivation after depolarizing voltage-clamp pulses. In 68% of the cells studied, those of larger capacitance, the M-current antagonists linopirdine and XE-991 reduced the amplitude of the M-current by 54%+/-7% and 50%+/-3%. The muscarinic-receptor agonist oxotremorine-M also significantly reduced the M-current by 58%+/-12% in the cells. The action of oxotremorine-M was blocked by atropine, thus indicating its cholinergic nature. The erg-channel blocker E-4031 did not significantly modify the M-current amplitude. In current-clamp experiments, linopirdine, XE-991, and oxotremorine-M modified the discharge response to current pulses from single spike to multiple spiking, reducing the adaptation of the electrical discharge. Our results indicate that large soma-size cultured vestibular-afferent neurons (most probably calyx-bearing neurons) express the M-current and that the modulation of this current by activation of muscarinic-receptor reduces its spike-frequency adaptation.

Sensory-Motor Adaptation to Space Flight: Human Balance Control and Artificial Gravity

NASA Technical Reports Server (NTRS)

Paloski, William H.

2004-01-01

Gravity, which is sensed directly by the otolith organs and indirectly by proprioceptors and exteroceptors, provides the CNS a fundamental reference for estimating spatial orientation and coordinating movements in the terrestrial environment. The sustained absence of gravity during orbital space flight creates a unique environment that cannot be reproduced on Earth. Loss of this fundamental CNS reference upon insertion into orbit triggers neuro-adaptive processes that optimize performance for the microgravity environment, while its reintroduction upon return to Earth triggers neuro-adaptive processes that return performance to terrestrial norms. Five pioneering symposia on The Role of the Vestibular Organs in the Exploration of Space were convened between 1965 and 1970. These innovative meetings brought together the top physicians, physiologists, and engineers in the vestibular field to discuss and debate the challenges associated with human vestibular system adaptation to the then novel environment of space flight. These highly successful symposia addressed the perplexing problem of how to understand and ameliorate the adverse physiological effects on humans resulting from the reduction of gravitational stimulation of the vestibular receptors in space. The series resumed in 2002 with the Sixth Symposium, which focused on the microgravity environment as an essential tool for the study of fundamental vestibular functions. The three day meeting included presentations on historical perspectives, vestibular neurobiology, neurophysiology, neuroanatomy, neurotransmitter systems, theoretical considerations, spatial orientation, psychophysics, motor integration, adaptation, autonomic function, space motion sickness, clinical issues, countermeasures, and rehabilitation. Scientists and clinicians entered into lively exchanges on how to design and perform mutually productive research and countermeasure development projects in the future. The problems posed by long duration missions dominated these discussions and were driven by the paucity of data available. These issues along with more specific recommendations arising from the above discussions will be addressed an upcoming issue of the Journal of Vestibular Research.

Post-spaceflight orthostatic intolerance: possible relationship to microgravity-induced plasticity in the vestibular system

NASA Technical Reports Server (NTRS)

Yates, B. J.; Kerman, I. A.

1998-01-01

Even after short spaceflights, most astronauts experience at least some postflight reduction of orthostatic tolerance; this problem is severe in some subjects. The mechanisms leading to postflight orthostatic intolerance are not well-established, but have traditionally been thought to include the following: changes in leg hemodynamics, alterations in baroreceptor reflex gain, decreases in exercise tolerance and aerobic fitness, hypovolemia, and altered sensitivity of beta-adrenergic receptors in the periphery. Recent studies have demonstrated that signals from vestibular otolith organs play an important role in regulating blood pressure during changes in posture in a 1-g environment. Because spaceflight results in plastic changes in the vestibular otolith organs and in the processing of inputs from otolith receptors, it is possible that another contributing factor to postflight orthostatic hypotension is alterations in the gain of vestibular influences on cardiovascular control. Preliminary data support this hypothesis, although controlled studies will be required to determine the relationship between changes in the vestibular system and orthostatic hypotension following exposure to microgravity. Copyright 1998 Elsevier Science B.V.

The Development of the Vestibular Apparatus Under Conditions of Weightlessness

NASA Technical Reports Server (NTRS)

Vinnikov, Y. A.; Gazenko, O. G.; Lychakov, D. V.; Palmbakh, L. R.

1984-01-01

A series of experiments has been carried out on the effect of space flight conditions on morphogenesis and the structure of the vestibular apparatus in amphibian and fish larvae. Larval development proceeded in weightlessness without serious morphological defects. The vestibular apparatus developed; its organization in the experimental animals did not differ qualitatively from that in the controls. The specific external stimulus (gravitation) appears not to be a necessary condition for the development of a gravitation receptor in ontogenesis although the appearance of the vestibular apparatus in phylogenesis was apparently related to this stimulus.

Vestibular autonomic regulation (including motion sickness and the mechanism of vomiting)

NASA Technical Reports Server (NTRS)

Balaban, C. D.

1999-01-01

Autonomic manifestations of vestibular dysfunction and motion sickness are well established in the clinical literature. Recent studies of 'vestibular autonomic regulation' have focused predominantly on autonomic responses to stimulation of the vestibular sense organs in the inner ear. These studies have shown that autonomic responses to vestibular stimulation are regionally selective and have defined a 'vestibulosympathetic reflex' in animal experiments. Outside the realm of experimental preparations, however, the importance of vestibular inputs in autonomic regulation is unclear because controls for secondary factors, such as affective/emotional responses and cardiovascular responses elicited by muscle contraction and regional blood pooling, have been inadequate. Anatomic and physiologic evidence of an extensive convergence of vestibular and autonomic information in the brainstem suggests though that there may be an integrated representation of gravitoinertial acceleration from vestibular, somatic, and visceral receptors for somatic and visceral motor control. In the case of vestibular dysfunction or motion sickness, the unpleasant visceral manifestations (e.g. epigastric discomfort, nausea or vomiting) may contribute to conditioned situational avoidance and the development of agoraphobia.

Role of platelet-activating factor in long-term potentiation of the rat medial vestibular nuclei.

PubMed

Grassi, S; Francescangeli, E; Goracci, G; Pettorossi, V E

1998-06-01

In rat brain stem slices, we investigated the role of platelet activating factor (PAF) in long-term potentiation (LTP) induced in the ventral part of the medial vestibular nuclei (MVN) by high-frequency stimulation (HFS) of the primary vestibular afferent. The synaptosomal PAF receptor antagonist, BN-52021 was administered before and after HFS. BN-52021 did not modify the vestibular potentials under basal conditions, but it reduced the magnitude of potentiation induced by HFS, which completely developed after the drug wash-out. The same effect was obtained by using CV-62091, a more potent PAF antagonist at microsomal binding sites, but with concentrations higher than those of BN-52021. By contrast both BN-52021 and CV-6209 had no effect on the potentiation once induced. This demonstrates that PAF is involved in the induction but not in the maintenance of vestibular long-term effect through activation of synaptosomal PAF receptors. In addition, we analyzed the effect of the PAF analogue, 1-O-hexadecyl-2-O- (methylcarbamyl)-sn-glycero-3-phosphocoline (MC-PAF) and the inactive PAF metabolite, 1-O-hexadecyl-sn-glycero-3-phosphocoline (Lyso-PAF) on vestibular responses. Our results show that MC-PAF, but not Lyso-PAF induced potentiation. This potentiation was prevented by D,L-2-amino 5-phosphonopentanoic acid, suggesting an involvement of N-methyl-D-aspartate receptors. Furthermore, under BN-52021 and CV-6209, the MC-PAF potentiation was reduced or abolished. The dose-effect curve of MC-PAF showed a shift to the right greater under BN-52021 than under CV-6209, confirming the main dependence of MC-PAF potentiation on the activation of synaptosomal PAF receptors. Our results suggest that PAF can be released in the MVN after the activation of postsynaptic mechanisms triggering LTP, and it may act as a retrograde messenger which activates the presynaptic mechanisms facilitating synaptic plasticity.

Vestibular sensory functional status of cochlear implanted ears versus non-implanted ears in bilateral profound deaf adults.

PubMed

Cozma, Romică Sebastian; Dima-Cozma, Lucia Corina; Rădulescu, Luminiţa Mihaela; Hera, Maria Cristina; Mârţu, Cristian; Olariu, Raluca; Cobzeanu, Bogdan Mihail; Bitere, Oana Roxana; Cobzeanu, Mihail Dan

2018-01-01

Patients with hearing loss who underwent cochlear implantation can present symptomatic or asymptomatic vestibular damages earlier or later after the surgery. The vestibular permanent lesions could be acute, produced by surgical trauma or could be progressive due to local morphological changes made by the presence of the portelectrode in the inner ear (fibrosis related, ossification, basilar membrane distortion, endolymphatic hydrops). Besides histopathological findings in inner ear of cochlear implanted patients, the vestibular permanent damages could be found by assessment of clinical vestibular status. This study reports the sensorial vestibular functional findings for adults in cochlear implanted ears related to the electrode insertion type (cochleostomy or round window approach) and comparing to non-implanted deaf ears. A total of 20 adult patients with 32 cochlear implanted ears (12 patients with binaural cochlear implant and eight with monoaural) were selected for postoperatory vestibular examination by cervical and ocular vestibular myogenic potentials and vestibular caloric tests. The same tests were made for a control group of 22 non-implanted deaf ears. Functional testing results were reported related to the electrode insertion approach. For the cochleostomy group, we found different deficits: in 40% for saccular function, 44% for utricular function, and 12% horizontal canal dysfunction. In round window group, the deficit was present in 14.29% for saccular function, 28.57% for utricular function, and 28.58% for horizontal canal. In 46.88% of implanted ears, the vestibular function was completely preserved on all tested sensors. In conclusion, the vestibular functional status after inner ear surgery presents sensorial damages in 53.12% ears compare with the vestibular dysfunction existing in 50% of deaf non-operated ears. Round window insertion allows for better conservation of the vestibular function.

Risk of Impaired Control of Spacecraft/Associated Systems and Decreased Mobility Due to Vestibular/Sensorimotor Alterations Associated with Space flight

NASA Technical Reports Server (NTRS)

Bloomberg, Jacob J.; Reschke, Millard F.; Clement, Gilles R.; Mulavara, Ajitkumar P.; Taylor, Laura C..

2015-01-01

Control of vehicles and other complex systems is a high-level integrative function of the central nervous system (CNS). It requires well-functioning subsystem performance, including good visual acuity, eye-hand coordination, spatial and geographic orientation perception, and cognitive function. Evidence from space flight research demonstrates that the function of each of these subsystems is altered by removing gravity, a fundamental orientation reference, which is sensed by vestibular, proprioceptive, and haptic receptors and used by the CNS for spatial orientation, posture, navigation, and coordination of movements. The available evidence also shows that the degree of alteration of each subsystem depends on a number of crew- and mission-related factors. There is only limited operational evidence that these alterations cause functional impacts on mission-critical vehicle (or complex system) control capabilities. Furthermore, while much of the operational performance data collected during space flight has not been available for independent analysis, those that have been reviewed are somewhat equivocal owing to uncontrolled (and/or unmeasured) environmental and/or engineering factors. Whether this can be improved by further analysis of previously inaccessible operational data or by development of new operational research protocols remains to be seen. The true operational risks will be estimable only after we have filled the knowledge gaps and when we can accurately assess integrated performance in off-nominal operational settings (Paloski et al. 2008). Thus, our current understanding of the Risk of Impaired Control of Spacecraft/Associated Systems and Decreased Mobility Due to Vestibular/Sensorimotor Alterations Associated with Space flight is limited primarily to extrapolation of scientific research findings, and, since there are limited ground-based analogs of the sensorimotor and vestibular changes associated with space flight, observation of their functional impacts is limited to studies performed in the space flight environment. Fortunately, many sensorimotor and vestibular experiments have been performed during and/or after space flight missions since 1959 (Reschke et al. 2007). While not all of these experiments were directly relevant to the question of vehicle/complex system control, most provide insight into changes in aspects of sensorimotor control that might bear on the physiological subsystems underlying this high-level integrated function.

Rescue of peripheral vestibular function in Usher syndrome mice using a splice-switching antisense oligonucleotide.

PubMed

Vijayakumar, Sarath; Depreux, Frederic F; Jodelka, Francine M; Lentz, Jennifer J; Rigo, Frank; Jones, Timothy A; Hastings, Michelle L

2017-09-15

Usher syndrome type 1C (USH1C/harmonin) is associated with profound retinal, auditory and vestibular dysfunction. We have previously reported on an antisense oligonucleotide (ASO-29) that dramatically improves auditory function and balance behavior in mice homozygous for the harmonin mutation Ush1c c.216G > A following a single systemic administration. The findings were suggestive of improved vestibular function; however, no direct vestibular assessment was made. Here, we measured vestibular sensory evoked potentials (VsEPs) to directly assess vestibular function in Usher mice. We report that VsEPs are absent or abnormal in Usher mice, indicating profound loss of vestibular function. Strikingly, Usher mice receiving ASO-29 treatment have normal or elevated vestibular response thresholds when treated during a critical period between postnatal day 1 and 5, respectively. In contrast, treatment of mice with ASO-29 treatment at P15 was minimally effective at rescuing vestibular function. Interestingly, ASO-29 treatment at P1, P5 or P15 resulted in sufficient vestibular recovery to support normal balance behaviors, suggesting a therapeutic benefit to balance with ASO-29 treatment at P15 despite the profound vestibular functional deficits that persist with treatment at this later time. These findings provide the first direct evidence of an effective treatment of peripheral vestibular function in a mouse model of USH1C and reveal the potential for using antisense technology to treat vestibular dysfunction. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Migraine, vertigo and migrainous vertigo: Links between vestibular and pain mechanisms.

PubMed

Balaban, Carey D

2011-01-01

This review develops the hypothesis that co-morbid balance disorders and migraine can be understood as additive effects of processing afferent vestibular and pain information in pre-parabrachial and pre-thalamic pathways, that have consequences on cortical mechanisms influencing perception, interoception and affect. There are remarkable parallel neurochemical phenotypes for inner ear and trigeminal ganglion cells and these afferent channels appear to converge in shared central pathways for vestibular and nociceptive information processing. These pathways share expression of receptors targeted by anti-migraine drugs. New evidence is also presented regarding the distribution of serotonin receptors in the planum semilunatum of the primate cristae ampullaris, which may indicate involvement of inner ear ionic homeostatic mechanisms in audiovestibular symptoms that can accompany migraine.

Exogenous glutamate induces short and long-term potentiation in the rat medial vestibular nuclei.

PubMed

Grassi, S; Frondaroli, A; Pessia, M; Pettorossi, V E

2001-08-08

In rat brain stem slices, high concentrations of exogenous glutamate induce long-term potentiation (LTP) of the field potentials evoked in the medial vestibular nuclei (MVN) by vestibular afferent stimulation. At low concentrations, glutamate can also induce short-term potentiation (STP), indicating that LTP and STP are separate events depending on the level of glutamatergic synapse activation. LTP and STP are prevented by blocking NMDA receptors and nitric oxide (NO) synthesis. Conversely, blocking platelet-activating factor (PAF) and group I metabotropic glutamate receptors only prevents the full development of LTP. Moreover, in the presence of blocking agents, glutamate causes transient inhibition, suggesting that when potentiation is impeded, exogenous glutamate can activate presynaptic mechanisms that reduce glutamate release.

[Proprioceptive sensitivity and orofacial functions].

PubMed

Auriol, M; Coutand, A; Crinetz, V; Chomette, G; Doumit, A; Lucht, M

1985-01-01

Proprioceptive sensibility from stimulation of muscle, ligament articular and vestibular receptors plays a determining role in the regulation of tone, of the resting position of the mandible, of head posture and of the closure pathway of the mandible. Studies conducted on temporomandibular joints of fetuses and adult subjects failed to demonstrate the specialized corpuscles (a fact previously noted by Ramfjord) in the temporomaxillary joint capsule, described typically in other joints. In contrast, however, histology showed a particularly rich population of muscle receptors adjacent to this joint, this being only one of several particular characteristics.

Insertional Mutagenesis for Genes involved in Otic/Vestibular Development and Function in Xenopus Tropicalis

NASA Technical Reports Server (NTRS)

Torrejon, Marcela; Li, Erica; Nguyen, Minh; Winfree, Seth; Wang, Esther; Reinsch, Sigrid; Dalton, Bonnie (Technical Monitor)

2002-01-01

Sensitivity to gravity is essential for spatial orientation. Consequently, the gravity receptor system is one of the phylogenetically oldest sensory systems, and the special adaptations that enhance sensitivity to gravity are highly conserved. The main goal of this project is to use Xenopus (frog) to identify genes expressed during vestibular and auditory development. These studies will lead a better understanding of the molecular mechanisms involved in vestibular and auditory development and function. We are using a gene-trap approach in Xenopus tropicalis with the green fluorescent protein (GFP) gene as the transgene reporter. GFP expression occurs only when the GFP gene is correctly integrated in actively transcribed genes. Using the GFP as a tag we can easily identify and clone the mutated gene. In addition, we can study the function of the mutated gene by analyzing the defects generated by insertion of the GFP transgene. To date we have tissue specific GFP expression in X. tropicalis including expression in ear, neural tube, kidney, muscle, eyes and nose. Our transgenic animals will soon reach maturity so that we can outcross them and analyze their progeny. Our next goal is to isolate RNA from our transgenics and clone the tagged genes using RACE-PCR. Currently we are optimizing the RACE-PCR method using transgenics with crystallin GFP expression.

Vestibulo-ocular and vestibulospinal function before and after cochlear implant surgery

NASA Technical Reports Server (NTRS)

Black, F. O.; Lilly, D. J.; Peterka, R. J.; Fowler, L. P.; Simmons, F. B.

1987-01-01

Vestibular function in cochlear implant candidates varies from normal to total absence of function. In patients with intact vestibular function preoperatively, invasion of the otic capsule places residual vestibular function at risk. Speech-processing strategies that result in large amplitude electrical transients or strategies that employ high amplitude broad frequency carrier signals have the potential for disrupting vestibular function. Five patients were tested with and without electrical stimulation via cochlear electrodes. Two patients experienced subjective vestibular effects that were quickly resolved. No long-term vestibular effects were noted for the two types of second generation cochlear implants evaluated. Histopathological findings from another patient, who had electrically generated vestibular reflex responses to intramodiolar electrodes, indicated that responses elicited were a function of several variables including electrode location, stimulus intensity, stimulus amplitude, and stimulus frequency. Differential auditory, vestibulocolic, and vestibulospinal reflexes were demonstrated from the same electrode as a function of stimulus amplitude, frequency, and duration.

Altered vestibular function in fetal and newborn rats gestated in space

NASA Technical Reports Server (NTRS)

Ronca, A. E.; Alberts, J. R.

1997-01-01

Researchers evaluated vestibular development and function in rat pups flown during gestation on the NASA-NIH R1 and R2 missions. Fetal and postnatal vestibular function were examined. Altered vestibular-mediated responses in the experimental fetal pups are attributed to either direct effect of gravity on the vestibular system or indirect effects of microgravity transduced through the mother. The postnatal tests confirmed the hypothesis that the vestibular system continually adapts and responds to tonic stimulation.

The role of GABA in NMDA-dependent long term depression (LTD) of rat medial vestibular nuclei.

PubMed

Grassi, S; Della Torre, G; Capocchi, G; Zampolini, M; Pettorossi, V E

1995-11-20

The role of GABA in NMDA-dependent long term depression (LTD) in the medial vestibular nuclei (MVN) was studied on rat brainstem slices. High frequency stimulation (HFS) of the primary vestibular afferents induces a long lasting reduction of the polysynaptic (N2) component of the field potentials recorded in the dorsal portion of the MVN. The induction but not the maintenance of this depression was abolished by AP5, a specific blocking agent for glutamate NMDA receptors. The involvement of GABA in mediating the depression was checked by applying the GABAA and GABAB receptor antagonists, bicuculline and saclofen, before and after HFS. Under bicuculline and saclofen perfusion, HFS provoked a slight potentiation of the N2 wave, while the N2 depression clearly emerged after drug wash-out. This indicates that GABA is not involved in inducing the long term effect, but it is necessary for its expression. Similarly, the LTD reversed and a slight potentiation appeared when both drugs were administered after its induction. Most of these effects were due to the bicuculline, suggesting that GABAA receptors contribute to LTD more than GABAB do. According to our results, it is unlikely that the long lasting vestibular depression is the result of a homosynaptic LTD. On the contrary, our findings suggest that the depression is due to an enhancement of the GABA inhibitory effect, caused by an HFS dependent increase in gabaergic interneuron activity, which resets vestibular neuron excitability at a lower level.

Association between vestibular function and motor performance in hearing-impaired children.

PubMed

Maes, Leen; De Kegel, Alexandra; Van Waelvelde, Hilde; Dhooge, Ingeborg

2014-12-01

The clinical balance performance of normal-hearing (NH) children was compared with the balance performance of hearing-impaired (HI) children with and without vestibular dysfunction to identify an association between vestibular function and motor performance. Prospective study. Tertiary referral center. Thirty-six children (mean age, 7 yr 5 mo; range, 3 yr 8 mo-12 yr 11 mo) divided into three groups: NH children with normal vestibular responses, HI children with normal vestibular responses, and HI children with abnormal vestibular function. A vestibular test protocol (rotatory and collic vestibular evoked myogenic potential testing) in combination with three clinical balance tests (balance beam walking, one-leg hopping, one-leg stance). Clinical balance performance. HI children with abnormal vestibular test results obtained the lowest quotients of motor performance, which were significantly lower compared with the NH group (p < 0.001 for balance beam walking and one-leg stance; p = 0.003 for one-leg hopping). The balance performance of the HI group with normal vestibular responses was better in comparison with the vestibular impaired group but still significantly lower compared with the NH group (p = 0.020 for balance beam walking; p = 0.001 for one-leg stance; not significant for one-leg hopping). These results indicate an association between vestibular function and motor performance in HI children, with a more distinct motor deterioration if a vestibular impairment is superimposed to the auditory dysfunction.

Activation of 5-HT7 receptors reverses NMDA-R-dependent LTD by activating PKA in medial vestibular neurons.

PubMed

Li, Yan-Hai; Han, Lei; Wu, Kenneth Lap Kei; Chan, Ying-Shing

2017-09-01

The medial vestibular nucleus (MVN) is a major output station for neurons that project to the vestibulo-spinal pathway. MVN neurons show capacity for long-term depression (LTD) during the juvenile period. We investigated LTD of MVN neurons using whole-cell patch-clamp recordings. High frequency stimulation (HFS) robustly induced LTD in 90% of type B neurons in the MVN, while only 10% of type A neurons were responsive, indicating that type B neurons are the major contributors to LTD in the MVN. The neuromodulator serotonin (5-HT) is known to modulate LTD in neural circuits of the cerebral cortex and the hippocampus. We therefore aim to determine the action of 5-HT on the LTD of type B MVN neurons and elucidate the relevant 5-HT receptor subtypes responsible for its action. Using specific agonists and antagonists of 5-HT receptors, we found that selective activation of 5-HT 7 receptor in type B neurons in the MVN of juvenile (P13-16) rats completely abolished NMDA-receptor-mediated LTD in a protein kinase A (PKA)-dependent manner. Our finding that 5-HT restricts plasticity of type B MVN neurons via 5-HT 7 receptors offers a mechanism whereby vestibular tuning contributes to the maturation of the vestibulo-spinal circuit and highlights the role of 5-HT in postural control. Copyright © 2017 Elsevier Ltd. All rights reserved.

Vestibular-evoked myogenic potential in patients with unilateral vestibular neuritis: abnormal VEMP and its recovery.

PubMed

Ochi, Kentaro; Ohashi, Toru; Watanabe, Shoji

2003-02-01

The incidence of inferior vestibular nerve disorders in patients suffering from unilateral vestibular neuritis and the recovery of these disorders were evaluated by monitoring the vestibular-evoked myogenic potential (VEMP). Eight patients ranged from 21 to 73 years that suffered from unilateral vestibular neuritis underwent VEMP and caloric testing. Abnormal VEMP was observed in two of the eight patients with unilateral vestibular neuritis. Two patients were diagnosed as having an inferior vestibular nerve disorder. One of these patients showed recovery of the inferior vestibular nerve function as assessed by the VEMP. Disorders of the inferior vestibular nerve function and their recovery was confirmed by our current results. The time course of recoveries of the superior and inferior vestibular nerve systems were similar in the two patients.

[Effectiveness of Self-efficacy Promoting Vestibular Rehabilitation Program for Patients with Vestibular Hypofunction].

PubMed

Lee, Hyun Jung; Choi-Kwon, Smi

2016-10-01

In this study an examination was done of the effect of self-efficacy promoting vestibular rehabilitation (S-VR) on dizziness, exercise selfefficacy, adherence to vestibular rehabilitation (VR), subjective and objective vestibular function, vestibular compensation and the recurrence of dizziness in patients with vestibular hypofunction. This was a randomized controlled study. Data were collected 3 times at baseline, 4 and 8 weeks after beginning the intervention. Outcome measures were level of dizziness, exercise self-efficacy, and level of adherence to VR. Subjective and objective vestibular function, vestibular compensation and the recurrence of dizziness were also obtained. Data were analyzed using Windows SPSS 21.0 program. After 4 weeks of S-VR, there was no difference between the groups for dizziness, subjective and objective vestibular functions. However, exercise self-efficacy and adherence to VR were higher in the experimental group than in the control group. After 8 weeks of S-VR, dizziness (p=.018) exercise self-efficacy (p<.001), adherence to VR (p<.001), total-dizziness handicap inventory (DHI) (p=.012), vision analysis ratio (p=.046) in the experimental group differ significantly from that of the control group. The number of patients with recurring dizziness were higher in the control group than in the experimental group (p<.001). The results indicate that continuous 8 weeks of S-VR is effective in reducing dizziness, and improving exercise self-efficacy, subjective vestibular function and adherence to VR. Objective vestibular function and vestibular compensation were also improved in the experimental group at the end of 8 weeks of S-VR.

To develop behavioral tests of vestibular functioning in the Wistar rat

NASA Technical Reports Server (NTRS)

Nielson, H. C.

1980-01-01

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.

Quantifying utricular stimulation during natural behavior

PubMed Central

Rivera, Angela R. V.; Davis, Julian; Grant, Wally; Blob, Richard W.; Peterson, Ellengene; Neiman, Alexander B.; Rowe, Michael

2012-01-01

The use of natural stimuli in neurophysiological studies has led to significant insights into the encoding strategies used by sensory neurons. To investigate these encoding strategies in vestibular receptors and neurons, we have developed a method for calculating the stimuli delivered to a vestibular organ, the utricle, during natural (unrestrained) behaviors, using the turtle as our experimental preparation. High-speed digital video sequences are used to calculate the dynamic gravito-inertial (GI) vector acting on the head during behavior. X-ray computed tomography (CT) scans are used to determine the orientation of the otoconial layer (OL) of the utricle within the head, and the calculated GI vectors are then rotated into the plane of the OL. Thus, the method allows us to quantify the spatio-temporal structure of stimuli to the OL during natural behaviors. In the future, these waveforms can be used as stimuli in neurophysiological experiments to understand how natural signals are encoded by vestibular receptors and neurons. We provide one example of the method which shows that turtle feeding behaviors can stimulate the utricle at frequencies higher than those typically used in vestibular studies. This method can be adapted to other species, to other vestibular end organs, and to other methods of quantifying head movements. PMID:22753360

Left hemispheric dominance of vestibular processing indicates lateralization of cortical functions in rats.

PubMed

Best, Christoph; Lange, Elena; Buchholz, Hans-Georg; Schreckenberger, Mathias; Reuss, Stefan; Dieterich, Marianne

2014-11-01

Lateralization of cortical functions such as speech dominance, handedness and processing of vestibular information are present not only in humans but also in ontogenetic older species, e.g. rats. In human functional imaging studies, the processing of vestibular information was found to be correlated with the hemispherical dominance as determined by the handedness. It is located mainly within the right hemisphere in right handers and within the left hemisphere in left handers. Since dominance of vestibular processing is unknown in animals, our aim was to study the lateralization of cortical processing in a functional imaging study applying small-animal positron emission tomography (microPET) and galvanic vestibular stimulation in an in vivo rat model. The cortical and subcortical network processing vestibular information could be demonstrated and correlated with data from other animal studies. By calculating a lateralization index as well as flipped region of interest analyses, we found that the vestibular processing in rats follows a strong left hemispheric dominance independent from the "handedness" of the animals. These findings support the idea of an early hemispheric specialization of vestibular cortical functions in ontogenetic older species.

Role of nitric oxide in long-term potentiation of the rat medial vestibular nuclei.

PubMed

Grassi, S; Pettorossi, V E

2000-01-01

In rat brainstem slices, we investigated the role of nitric oxide in long-term potentiation induced in the ventral portion of the medial vestibular nuclei by high-frequency stimulation of the primary vestibular afferents. The nitric oxide scavenger [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide ] and the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester were administered before and after induction of potentiation. Both drugs completely prevented long-term potentiation, whereas they did not impede the potentiation build-up, or affect the already established potentiation. These results demonstrate that the induction, but not the maintenance of vestibular long-term potentiation, depends on the synthesis and release into the extracellular medium of nitric oxide. In addition, we analysed the effect of the nitric oxide donor sodium nitroprusside on vestibular responses. Sodium nitroprusside induced long-term potentiation, as evidenced through the field potential enhancement and unit peak latency decrease. This potentiation was impeded by D, L-2-amino-5-phosphonopentanoic acid, and was reduced under blockade of synaptosomal platelet-activating factor receptors by ginkgolide B and group I metabotropic glutamate receptors by (R,S)-1-aminoindan-1, 5-dicarboxylic acid. When reduced, potentiation fully developed following the washout of antagonist, demonstrating an involvement of platelet-activating factor and group I metabotropic glutamate receptors in its full development. Potentiation induced by sodium nitroprusside was also associated with a decrease in the paired-pulse facilitation ratio, which persisted under ginkgolide B, indicating that nitric oxide increases glutamate release independently of platelet-activating factor-mediated presynaptic events. We suggest that nitric oxide, released after the activation of N-methyl-D-aspartate receptors, acts as a retrograde messenger leading to an enhancement of glutamate release to a sufficient level for triggering potentiation. Once the synaptic efficacy has changed, it becomes a long-lasting phenomenon only through a subsequent action of platelet-activating factor.

Structural and functional connectivity mapping of the vestibular circuitry from human brainstem to cortex.

PubMed

Kirsch, V; Keeser, D; Hergenroeder, T; Erat, O; Ertl-Wagner, B; Brandt, T; Dieterich, M

2016-04-01

Structural and functional interconnections of the bilateral central vestibular network have not yet been completely delineated. This includes both ipsilateral and contralateral pathways and crossing sites on the way from the vestibular nuclei via the thalamic relay stations to multiple "vestibular cortex" areas. This study investigated "vestibular" connectivity in the living human brain in between the vestibular nuclei and the parieto-insular vestibular cortex (PIVC) by combined structural and functional connectivity mapping using diffusion tensor imaging and functional connectivity magnetic resonance imaging in 24 healthy right-handed volunteers. We observed a congruent functional and structural link between the vestibular nuclei and the ipsilateral and contralateral PIVC. Five separate and distinct vestibular pathways were identified: three run ipsilaterally, while the two others cross either in the pons or the midbrain. Two of the ipsilateral projections run through the posterolateral or paramedian thalamic subnuclei, while the third bypasses the thalamus to reach the inferior part of the insular cortex directly. Both contralateral pathways travel through the posterolateral thalamus. At the cortical level, the PIVC regions of both hemispheres with a right hemispherical dominance are interconnected transcallosally through the antero-caudal splenium. The above-described bilateral vestibular circuitry in its entirety takes the form of a structure of a rope ladder extending from the brainstem to the cortex with three crossings in the brainstem (vestibular nuclei, pons, midbrain), none at thalamic level and a fourth cortical crossing through the splenium of the corpus callosum.

Vestibular function outcomes after vestibular neurectomy in Meniere disease: can vestibular neurectomy provide complete vestibular deafferentation?

PubMed

Leveque, M; Seidermann, L; Tran, H; Langagne, T; Ulmer, E; Chays, A

2010-06-01

Vestibular neurectomy is considered the reference treatment of incapacitating vertigo accompanying Meniere disease, with an efficiency rate of 85-95% in most literature reports. The aim of this study is to evaluate if vestibular neurectomy can provide a complete vestibular deafferentation by investigating complete vestibular function after surgery. Prospective study. Twenty-four patients suffering from incapacitated Meniere vertigo crisis beneficiated from a vestibular neurectomy by retrosigmoid approach. The average time between surgery and vestibular evaluation was 1 year. We performed (i) kinetic test, (ii) caloric test and (iii) vibration-induced nystagmus (VIN) at 30, 60 and 100Hz under videonystagmography recording, (iv) vestibular evoked myogenic potentials (VEMP), (v) video head impulsed test (VHIT) for each semicircular canals and (vi) an evaluation of visual vertical and horizontal subjective (VVS and HVS). On clinical evaluation, all the patients except one had never experienced any recurrence of vertigo crisis after surgery. The 24 patients would definitely undergo the surgery again. On vestibular evaluation, on the operated side, all patients showed a total areflexia at caloric test; 23 patients had no VEMP response; 23 patients had abolished canals response to VHIT. All the patients had VVS and HVS deviated towards the operated side; 23 patients had a high velocity VIN from 30 to 60Hz. This study proves that vestibular neurectomy can provide a complete vestibular deafferentation. We discuss this vestibular evaluation protocol and the main difficulties encounter during surgery, which could lead to partial nerve section and partial relief, and explain residual vestibular function after vestibular neurectomy. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

Vestibular ontogeny: Measuring the influence of the dynamic environment

NASA Technical Reports Server (NTRS)

Jones, Timothy A.; Devries, Sherri M.; Dubois, Linda M.; Nelson, Rick C.

1993-01-01

In comparison to other special senses, we are only meagerly informed about the development of vestibular function and the mechanisms that may operate to control or influence the course of vestibular ontogeny. Perhaps one contributing factor to this disparity is the difficulty of evaluating vestibular sense organs directly and noninvasively. The present report describes a recently developed direct noninvasive vestibular function test that can be used to address many basic questions about the developing vestibular system. More particularly, the test can be used to examine the effects of the dynamic environment (e.g. gravitational field and vibration) on vestibular ontogeny.

Recovery of vestibular function following hair cell destruction by streptomycin

NASA Technical Reports Server (NTRS)

Jones, T. A.; Nelson, R. C.

1992-01-01

Can the vestibular periphery of warm-blooded vertebrates recover functionally from severe sensory hair cell loss? Recent findings in birds suggest a mechanism for recovery but in fact no direct functional evidence has been reported. We produced vestibular hair cell lesions using the ototoxic agent streptomycin sulfate (600 mg/kg/day, 8 days, chicks, Gallus domesticus). Compound action potentials of the vestibular nerve were used as a direct measure of peripheral vestibular function. Vestibular thresholds, neural activation latencies and amplitudes were documented. Eight days of drug treatment elevated thresholds significantly (P < 0.001) and eliminated all but remnants of vestibular activity. Virtually complete physiological recovery occurred in all animals studied over a period of 70 days following treatment. Thresholds recovered within two weeks of drug treatment whereas the return of response morphologies including activation latencies and amplitudes required an additional 6-8 weeks.

[Air conducted ocular VEMP: II. First clinical investigations].

PubMed

Walther, L E; Schaaf, H; Sommer, D; Hörmann, K

2011-10-01

Vestibular-evoked myogenic potentials (VEMP) are widely used to assess vestibular function. Air conducted (AC) cervical VEMP (cVEMP) reflect sacculus and inferior vestibular nerve function. Ocular VEMP (oVEMP) however has been hardly examined up to now. In recent studies it has been assumed that AC oVEMP probably reflects superior vestibular nerve function. The aim of this pilot study was to evaluate clinical application of the AC oVEMP. AC oVEMP were recorded in patients with peripheral vestibular disorders (n=21). In addition thermal irritation and head impulse test were performed and AC cVEMP were recorded. For intense AC-sound stimulation tone bursts (500 Hz) with 100 dB nHL were used. In peripheral vestibular disorders AC oVEMP and AC cVEMP could be classified into: • type 1 (inferior vestibular neuritis) with loss of AC oVEMP but normal AC cVEMP, • type 2, probable type of superior vestibular neuritis, showing present AC cVEMP but loss of AC oVEMP, • type 3, probable complete vestibular neuritis, without AC oVEMP and AC cVEMP. AC oVEMP may be used as an appropriate test for clinical investigation in patients with vestibular disorders. AC oVEMP is an additional, essential test for assessing otolith function beside AC cVEMP. Further vestibular test are necessary for precise clinical interpretation. © Georg Thieme Verlag KG Stuttgart · New York.

A vestibular phenotype for Waardenburg syndrome?

NASA Technical Reports Server (NTRS)

Black, F. O.; Pesznecker, S. C.; Allen, K.; Gianna, C.

2001-01-01

OBJECTIVE: To investigate vestibular abnormalities in subjects with Waardenburg syndrome. STUDY DESIGN: Retrospective record review. SETTING: Tertiary referral neurotology clinic. SUBJECTS: Twenty-two adult white subjects with clinical diagnosis of Waardenburg syndrome (10 type I and 12 type II). INTERVENTIONS: Evaluation for Waardenburg phenotype, history of vestibular and auditory symptoms, tests of vestibular and auditory function. MAIN OUTCOME MEASURES: Results of phenotyping, results of vestibular and auditory symptom review (history), results of vestibular and auditory function testing. RESULTS: Seventeen subjects were women, and 5 were men. Their ages ranged from 21 to 58 years (mean, 38 years). Sixteen of the 22 subjects sought treatment for vertigo, dizziness, or imbalance. For subjects with vestibular symptoms, the results of vestibuloocular tests (calorics, vestibular autorotation, and/or pseudorandom rotation) were abnormal in 77%, and the results of vestibulospinal function tests (computerized dynamic posturography, EquiTest) were abnormal in 57%, but there were no specific patterns of abnormality. Six had objective sensorineural hearing loss. Thirteen had an elevated summating/action potential (>0.40) on electrocochleography. All subjects except those with severe hearing loss (n = 3) had normal auditory brainstem response results. CONCLUSION: Patients with Waardenburg syndrome may experience primarily vestibular symptoms without hearing loss. Electrocochleography and vestibular function tests appear to be the most sensitive measures of otologic abnormalities in such patients.

Video Head Impulse Testing (vHIT) and the Assessment of Horizontal Semicircular Canal Function.

PubMed

Riska, Kristal M; Murnane, Owen; Akin, Faith W; Hall, Courtney

2015-05-01

Vestibular function (specifically, horizontal semicircular canal function) can be assessed across a broad frequency range using several different techniques. The head impulse test is a qualitative test of horizontal semicircular canal function that can be completed at bedside. Recently, a new instrument (video head impulse test [vHIT]) has been developed to provide an objective assessment to the clinical test. Questions persist regarding how this test may be used in the overall vestibular test battery. The purpose of this case report is to describe vestibular test results (vHIT, rotational testing, vestibular evoked myogenic potentials, and balance and gait performance) in an individual with a 100% unilateral caloric weakness who was asymptomatic for dizziness, vertigo or imbalance. Comprehensive assessment was completed to evaluate vestibular function. Caloric irrigations, rotary chair testing, vHIT, and vestibular evoked myogenic potentials were completed. A 100% left-sided unilateral caloric weakness was observed in an asymptomatic individual. vHIT produced normal gain with covert saccades. This case demonstrates the clinical usefulness of vHIT as a diagnostic tool and indicator of vestibular compensation and functional status. American Academy of Audiology.

Vestibular involvement in cognition: Visuospatial ability, attention, executive function, and memory.

PubMed

Bigelow, Robin T; Agrawal, Yuri

2015-01-01

A growing body of literature suggests the inner ear vestibular system has a substantial impact on cognitive function. The strongest evidence exists in connecting vestibular function to the cognitive domain of visuospatial ability, which includes spatial memory, navigation, mental rotation, and mental representation of three-dimensional space. Substantial evidence also exists suggesting the vestibular system has an impact on attention and cognitive processing ability. The cognitive domains of memory and executive function are also implicated in a number of studies. We will review the current literature, discuss possible causal links between vestibular dysfunction and cognitive performance, and suggest areas of future research.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on Intraoperative Cranial Nerve Monitoring in Vestibular Schwannoma Surgery.

PubMed

Vivas, Esther X; Carlson, Matthew L; Neff, Brian A; Shepard, Neil T; McCracken, D Jay; Sweeney, Alex D; Olson, Jeffrey J

2018-02-01

Does intraoperative facial nerve monitoring during vestibular schwannoma surgery lead to better long-term facial nerve function? This recommendation applies to adult patients undergoing vestibular schwannoma surgery regardless of tumor characteristics. Level 3: It is recommended that intraoperative facial nerve monitoring be routinely utilized during vestibular schwannoma surgery to improve long-term facial nerve function. Can intraoperative facial nerve monitoring be used to accurately predict favorable long-term facial nerve function after vestibular schwannoma surgery? This recommendation applies to adult patients undergoing vestibular schwannoma surgery. Level 3: Intraoperative facial nerve can be used to accurately predict favorable long-term facial nerve function after vestibular schwannoma surgery. Specifically, the presence of favorable testing reliably portends a good long-term facial nerve outcome. However, the absence of favorable testing in the setting of an anatomically intact facial nerve does not reliably predict poor long-term function and therefore cannot be used to direct decision-making regarding the need for early reinnervation procedures. Does an anatomically intact facial nerve with poor electromyogram (EMG) electrical responses during intraoperative testing reliably predict poor long-term facial nerve function? This recommendation applies to adult patients undergoing vestibular schwannoma surgery. Level 3: Poor intraoperative EMG electrical response of the facial nerve should not be used as a reliable predictor of poor long-term facial nerve function. Should intraoperative eighth cranial nerve monitoring be used during vestibular schwannoma surgery? This recommendation applies to adult patients undergoing vestibular schwannoma surgery with measurable preoperative hearing levels and tumors smaller than 1.5 cm. Level 3: Intraoperative eighth cranial nerve monitoring should be used during vestibular schwannoma surgery when hearing preservation is attempted. Is direct monitoring of the eighth cranial nerve superior to the use of far-field auditory brain stem responses? This recommendation applies to adult patients undergoing vestibular schwannoma surgery with measurable preoperative hearing levels and tumors smaller than 1.5 cm. Level 3: There is insufficient evidence to make a definitive recommendation.  The full guideline can be found at: https://www.cns.org/guidelines/guidelines-manage-ment-patients-vestibular-schwannoma/chapter_4. Copyright © 2017 by the Congress of Neurological Surgeons

Aging of vestibular function evaluated using correlational vestibular autorotation test

PubMed Central

Hsieh, Li-Chun; Lin, Hung-Ching; Lee, Guo-She

2014-01-01

Background Imbalance from degeneration of vestibular end organs is a common problem in the elderly. However, the decline of vestibular function with aging was revealed in few vestibular function tests such as vestibular autorotation test (VAT). In the current VAT, there are drawbacks of poor test–retest reliability, slippage of the sensor at high-speed rotations, and limited data about the effect of aging. We developed a correlational-VAT (cVAT) system that included a small, light sensor (less than 20 g) with wireless data transmission technique to evaluate the aging of vestibular function. Material and methods We enrolled 53 healthy participants aged between 25 and 75 years and divided them into five age groups. The test conditions were vertical and horizontal head autorotations of frequencies from 0 to 3 Hz with closed eyes or open eyes. The cross-correlation coefficient (CCC) between eye velocity and head velocity was obtained for the head autorotations between 1 Hz and 3 Hz. The mean of the CCCs was used to represent the vestibular function. Results Age was significantly and negatively correlated with the mean CCC for all test conditions, including horizontal or vertical autorotations with open eyes or closed eyes (P<0.05). The mean CCC with open eyes declined significantly at 55–65 years old and the mean CCC with closed eyes declined significantly at 65–75 years old. Conclusion Vestibular function evaluated using mean CCC revealed a decline with age, and the function of visual-vestibulo-ocular reflex declined 10 years earlier than the function of vestibulo-ocular reflex. PMID:25214774

[Effects of electromagnetic fields emitted by cellular phone on auditory and vestibular labyrinth].

PubMed

Sievert, U; Eggert, S; Goltz, S; Pau, H W

2007-04-01

It is the subject of this study to investigate the biological effect of the HF radiation produced by the Global System for Mobile Communications-( GSM)-mobile phone on the inner ear with its sensors of the vestibular and auditive systems. Thermographic investigations made on various model materials and on the human temporal bone should show whether mobile phone does induce any increases of temperature which would lead to a relevant stimulus for the auditive and vestibular system or not. We carried out video-nystagmographic recordings of 13 subjects, brainstem electric response audiometry of 24 ears, and recordings of distorsion products of otoacoustic emissions of 20 ears. All tests were made with and without a mobile phone in use. The data was then analyzed for variation patterns in the functional parameters of the hearing and balance system that are subject to the (non)existence of electromagnetic radiation from the mobile phone. The thermographic investigations suggest that the mobile phone does not induce any increases of temperature which would lead to a relevant stimulus for the auditive and vestibular system. Video-nystagmographic recordings under field effect do not furnish any indication of vestibular reactions generated by field effects. Compared with the recording without field, the brainstem electric response audiometry under field effect did not reveal any changes of the parameters investigated, i. e. absolute latency of the peaks I, III, V and the interpeak latency between the peaks I and V. The distorsion products of otoacoustic emissions do not indicate, comparing the three measuring situations, i. e. before field effect, pulsed field and continuous field, any possible impacts of the HF field on the spectrum or levels of emissions for none of the probands. The investigations made show that the electromagnetic fields generated in using the mobile phone do not have an effect on the inner ear and auditive system to the colliculus inferior in the brainstem and on the vestibular receptors in the inner ear and the vestibular system.

Opposite long-term synaptic effects of 17β-estradiol and 5α-dihydrotestosterone and localization of their receptors in the medial vestibular nucleus of rats.

PubMed

Grassi, Silvarosa; Scarduzio, Mariangela; Panichi, Roberto; Dall'Aglio, Cecilia; Boiti, Cristiano; Pettorossi, Vito E

2013-08-01

In brainstem slices of male rats, we examined in single neurons of the medial vestibular nucleus (MVN) the effect of exogenous administration of estrogenic (17β-estradiol, E2) and androgenic (5α-dihydrotestosterone, DHT) steroids on the synaptic response to vestibular afferent stimulation. By whole cell patch clamp recordings we showed that E2 induced synaptic long-term potentiation (LTP) that was cancelled by the subsequent administration of DHT. Conversely, DHT induced synaptic long-term depression (LTD) that was partially reversed by E2. The electrophysiological findings were supported by immunohistochemical analysis showing the presence of estrogen (ER: α and β) and androgen receptors (AR) in the MVN neurons. We found that a large number of neurons were immunoreactive for ERα, ERβ, and AR and most of them co-localized ERβ and AR. We also showed the presence of P450-aromatase (ARO) in the MVN neurons, clearly proving that E2 can be locally synthesized in the MVN. On the whole, these results demonstrate a role of estrogenic and androgenic signals in modulating vestibular synaptic plasticity and suggest that the enhancement or depression of vestibular synaptic response may depend on the local conversion of T into E2 or DHT. Copyright © 2013 Elsevier Inc. All rights reserved.

Ontogeny of vestibular compound action potentials in the domestic chicken

NASA Technical Reports Server (NTRS)

Jones, S. M.; Jones, T. A.

2000-01-01

Compound action potentials of the vestibular nerve were measured from the surface of the scalp in 148 chickens (Gallus domesticus). Ages ranged from incubation day 18 (E18) to 22 days posthatch (P22). Responses were elicited using linear acceleration cranial pulses. Response thresholds decreased at an average rate of -0.45 dB/day. The decrease was best fit by an exponential model with half-maturity time constant of 5.1 days and asymptote of approximately -25.9 dB re:1.0 g/ms. Mean threshold approached within 3 dB of the asymptote by ages P6-P9. Similarly, response latencies decreased exponentially to within 3% of mature values at ages beyond P9. The half-maturity time constant for peripheral response peak latencies P1, N1, and P2 was comparable to thresholds and ranged from approximately 4.6 to 6.2 days, whereas central peaks (N2, P3, and N3) ranged from 2.9 to 3.4 days. Latency-intensity slopes for P1, N1, and P2 tended to decrease with age, reaching mature values within approximately 100 hours of hatching. Amplitudes increased as a function of age with average growth rates for response peaks ranging from 0.04 to 0.09 microV/day. There was no obvious asymptote to the growth of amplitudes over the ages studied. Amplitude-intensity slopes also increased modestly with age. The results show that gravity receptors are responsive to transient cranial stimuli as early as E19 in the chicken embryo. The functional response of gravity receptors continues to develop for many days after all major morphological structures are in place. Distinct maturational processes can be identified in central and peripheral neural relays. Functional improvements during maturation may result from refinements in the receptor epithelia, improvements in central and peripheral synaptic transmission, increased neural myelination, as well as changes in the mechanical coupling between the cranium and receptor organ.

Ontogeny of Vestibular Compound Action Potentials in the Domestic Chicken

PubMed Central

M. Jones, Sherri

2000-01-01

Compound action potentials of the vestibular nerve were measured from the surface of the scalp in 148 chickens (Gallus domesticus). Ages ranged from incubation day 18 (E18) to 22 days posthatch (P22). Responses were elicited using linear acceleration cranial pulses. Response thresholds decreased at an average rate of –0.45 dB/day. The decrease was best fit by an exponential model with half-maturity time constant of 5.1 days and asymptote of approximately –25.9 dB re:1.0 g/ms. Mean threshold approached within 3 dB of the asymptote by ages P6–P9. Similarly, response latencies decreased exponentially to within 3% of mature values at ages beyond P9. The half-maturity time constant for peripheral response peak latencies P1, N1, and P2 was comparable to thresholds and ranged from approximately 4.6 to 6.2 days, whereas central peaks (N2, P3, and N3) ranged from 2.9 to 3.4 days. Latency-intensity slopes for P1, N1, and P2 tended to decrease with age, reaching mature values within approximately 100 hours of hatching. Amplitudes increased as a function of age with average growth rates for response peaks ranging from 0.04 to 0.09 μV/day. There was no obvious asymptote to the growth of amplitudes over the ages studied. Amplitude-intensity slopes also increased modestly with age. The results show that gravity receptors are responsive to transient cranial stimuli as early as E19 in the chicken embryo. The functional response of gravity receptors continues to develop for many days after all major morphological structures are in place. Distinct maturational processes can be identified in central and peripheral neural relays. Functional improvements during maturation may result from refinements in the receptor epithelia, improvements in central and peripheral synaptic transmission, increased neural myelination, as well as changes in the mechanical coupling between the cranium and receptor organ. PMID:11545229

[Inferior vestibular neuritis: diagnosis using VEMP].

PubMed

Walther, L E; Repik, I

2012-02-01

Vestibular evoked myogenic potentials (VEMP) are a new method to establish the functional status of the otolith organs. The sacculocollic reflex of the cervical VEMP to air conduction (AC) reflects predominantly saccular function due to saccular afferents to the inferior vestibular nerve. We describe a case of inferior vestibular neuritis as a rare differential diagnosis of vestibular neuritis. Clinical signs were a normal caloric response, unilaterally absent AC cVEMPs and bilaterally preserved ocular VEMPs (AC oVEMPs).

Long-term potentiation in the rat medial vestibular nuclei depends on locally synthesized 17beta-estradiol.

PubMed

Grassi, Silvarosa; Frondaroli, Adele; Dieni, Cristina; Scarduzio, Mariangela; Pettorossi, Vito E

2009-08-26

In male rat brainstem slices, we investigated the involvement of locally synthesized 17beta-estradiol (E(2)) in the induction in the medial vestibular nucleus (MVN) of long-term potentiation (LTP) by high-frequency stimulation (HFS) of the primary vestibular afferents. We demonstrated that the blockade of aromatase by letrozole or of E(2) receptors (ERalpha and ERbeta) by ICI 182,780 prevented the HFS-induced LTP of the N1 wave of the evoked field potential (FP) without affecting baseline responses. Only prolonged afferent activation could induce low LTP. In contrast, HFS applied under a combined blockade of GABA(A) receptors and aromatase or ERs was still able to induce LTP, but it was significantly lower and slower. These findings demonstrate that E(2) does not have a tonic influence on the activity of the MVN neurons and provide the first evidence of the crucial role played by local synthesis of E(2) in inducing LTP. We suggest that the synthesis of E(2) occurs after aromatase activation during HFS and facilitates the development of vestibular synaptic plasticity by influencing glutamate and GABA transmission.

Vestibular evoked myogenic potentials in response to lateral skull taps are dependent on two different mechanisms.

PubMed

Brantberg, Krister; Westin, Magnus; Löfqvist, Lennart; Verrecchia, Luca; Tribukait, Arne

2009-05-01

To explore the mechanisms for skull tap induced vestibular evoked myogenic potentials (VEMP). The muscular responses were recorded over both sternocleidomastoid (SCM) muscles using skin electrodes. A skull tapper which provided a constant stimulus intensity was used to test cervical vestibular evoked myogenic potentials (VEMP) in response to lateral skull taps in healthy subjects (n=10) and in patients with severe unilateral loss of vestibular function (n=10). Skull taps applied approximately 2 cm above the outer ear canal caused highly reproducible VEMP. There were differences in VEMP in both normals and patients depending on side of tapping. In normals, there was a positive-negative ("normal") VEMP on the side contra-lateral to the skull tapping, but no significant VEMP ipsi-laterally. In patients, skull taps above the lesioned ear caused a contra-lateral positive-negative VEMP (as it did in the normals), in addition there was an ipsi-lateral negative-positive ("inverted") VEMP. When skull taps were presented above the healthy ear there was only a small contra-lateral positive-negative VEMP but, similar to the normals, no VEMP ipsi-laterally. The present data, in conjunction with earlier findings, support a theory that skull-tap VEMP responses are mediated by two different mechanisms. It is suggested that skull tapping causes both a purely ipsi-lateral stimulus side independent SCM response and a bilateral and of opposite polarity SCM response that is stimulus side dependent. Possibly, the skull tap induced VEMP responses are the sum of a stimulation of two species of vestibular receptors, one excited by vibration (which is rather stimulus site independent) and one excited by translation (which is more stimulus site dependent). Skull-tap VEMP probably have two different mechanisms. Separation of the two components might reveal the status of different labyrinthine functions.

Intranasal scopolamine affects the semicircular canals centrally and peripherally.

PubMed

Weerts, Aurélie P; Putcha, Lakshmi; Hoag, Stephen W; Hallgren, Emma; Van Ombergen, Angelique; Van de Heyning, Paul H; Wuyts, Floris L

2015-08-01

Space motion sickness (SMS), a condition caused by an intravestibular conflict, remains an important obstacle that astronauts encounter during the first days in space. Promethazine is currently the standard treatment of SMS, but scopolamine is used by some astronauts to prevent SMS. However, the oral and transdermal routes of administration of scopolamine are known to have substantial drawbacks. Intranasal administration of scopolamine ensures a fast absorption and rapid onset of therapeutic effect, which might prove to be suitable for use during spaceflights. The aim of this study was to evaluate the effects of intranasally administered scopolamine (0.4 mg) on the semicircular canals (SCCs) and the otoliths. This double-blind, placebo-controlled study was performed on 19 healthy male subjects. The function of the horizontal SCC and the vestibulo-ocular reflex, as well as the saccular function and utricular function, were evaluated. Scopolamine turned out to affect mainly the SCCs centrally and peripherally but also the utricles to a lesser extent. Centrally, the most probable site of action is the medial vestibular nucleus, where the highest density of muscarinic receptors has been demonstrated and afferent fibers from the SCCs and utricles synapse. Furthermore, our results suggest the presence of muscarinic receptors in the peripheral vestibular system on which scopolamine has a suppressive effect. Given the depressant actions on the SCCs, it is suggested that the pharmacodynamic effect of scopolamine may be attributed to the obliteration of intravestibular conflict that arises during (S)MS. Copyright © 2015 the American Physiological Society.

Vestibulo-oculomotor behaviour in rats following a transient unilateral vestibular loss induced by lidocaine.

PubMed

Magnusson, A K; Tham, R

2003-01-01

The effects of a transient vestibular nerve blockade, achieved by intra-tympanic instillation of lidocaine, were studied in rats by recording horizontal eye movements in darkness. Evaluation of the dose-response relationship showed that a maximal effect was attained with a concentration of 4% lidocaine. Within 15 min of lidocaine instillation, a vigorous spontaneous nystagmus was observed which reached maximal frequency and velocity of the slow phase after about 20 min. Subsequently, the nystagmus failed for approximately half an hour before it reappeared. This could be avoided by providing visual feedback in between the recordings in darkness or by a contralateral instillation of 2.5% lidocaine. It is suggested that the failure reflects an overload of the vestibulo-oculomotor circuits. After recovery from the nerve blockade, when the gaze was stable, dynamic vestibular tests were performed. They revealed that a decrease of the slow phase velocity gain and the dominant time constant during, respectively, sinusoidal- and step stimulation toward the unanaesthetised side, had developed with the nerve blockade. These modulations were impaired by a nodulo-uvulectomy but not by bilateral flocculectomy, which is consistent with the concept of vestibular habituation. A GABA(B) receptor antagonist, CGP 56433A, given systemically during the nerve blockade, aggravated the vestibular asymmetry. The same effect has previously been demonstrated in both short- (days) and long-term (months) compensated rats, by antagonising the GABA(B) receptor. In summary, this study provides the first observations of vestibulo-oculomotor disturbances during the first hour after a rapid and transient unilateral vestibular loss in the rat. By using this method, it is possible to study immediate behavioural consequences and possible neural changes that might outlast the nerve blockade.

Experimental and clinical study of EHF treatment of vascular-vestibular dysfunction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mal`tsev, A.E.; Abakarov, A.T.; Istomin, V.S.

1994-07-01

The authors present the results of a study of the effectiveness of EHF radiation on the cerebral hemodynamics, bioelectrical activity of the cerebral cortex, and functional state of the vestibular analyzer in chronic studies of cats using a model of vascular-vestibular dysfunction. The clinical part of the work reflects the results of studies of the functional state of cerebral blood circulation and the vestibular analyzer during the EHF treatment of angiovertebrogenic vestibular dysfunction in a background of initial manifestations of cerebral blood supply deficiency (angiodistonic variant).

EphB2 guides axons at the midline and is necessary for normal vestibular function

NASA Technical Reports Server (NTRS)

Cowan, C. A.; Yokoyama, N.; Bianchi, L. M.; Henkemeyer, M.; Fritzsch, B.

2000-01-01

Mice lacking the EphB2 receptor tyrosine kinase display a cell-autonomous, strain-specific circling behavior that is associated with vestibular phenotypes. In mutant embryos, the contralateral inner ear efferent growth cones exhibit inappropriate pathway selection at the midline, while in mutant adults, the endolymph-filled lumen of the semicircular canals is severely reduced. EphB2 is expressed in the endolymph-producing dark cells in the inner ear epithelium, and these cells show ultrastructural defects in the mutants. A molecular link to fluid regulation is provided by demonstrating that PDZ domain-containing proteins that bind the C termini of EphB2 and B-ephrins can also recognize the cytoplasmic tails of anion exchangers and aquaporins. This suggests EphB2 may regulate ionic homeostasis and endolymph fluid production through macromolecular associations with membrane channels that transport chloride, bicarbonate, and water.

Artificial Balance: Restoration of the Vestibulo-Ocular Reflex in Humans with a Prototype Vestibular Neuroprosthesis

PubMed Central

Perez Fornos, Angelica; Guinand, Nils; van de Berg, Raymond; Stokroos, Robert; Micera, Silvestro; Kingma, Herman; Pelizzone, Marco; Guyot, Jean-Philippe

2014-01-01

The vestibular system plays a crucial role in the multisensory control of balance. When vestibular function is lost, essential tasks such as postural control, gaze stabilization, and spatial orientation are limited and the quality of life of patients is significantly impaired. Currently, there is no effective treatment for bilateral vestibular deficits. Research efforts both in animals and humans during the last decade set a solid background to the concept of using electrical stimulation to restore vestibular function. Still, the potential clinical benefit of a vestibular neuroprosthesis has to be demonstrated to pave the way for a translation into clinical trials. An important parameter for the assessment of vestibular function is the vestibulo-ocular reflex (VOR), the primary mechanism responsible for maintaining the perception of a stable visual environment while moving. Here we show that the VOR can be artificially restored in humans using motion-controlled, amplitude modulated electrical stimulation of the ampullary branches of the vestibular nerve. Three patients received a vestibular neuroprosthesis prototype, consisting of a modified cochlear implant providing vestibular electrodes. Significantly higher VOR responses were observed when the prototype was turned ON. Furthermore, VOR responses increased significantly as the intensity of the stimulation increased, reaching on average 79% of those measured in healthy volunteers in the same experimental conditions. These results constitute a fundamental milestone and allow us to envision for the first time clinically useful rehabilitation of patients with bilateral vestibular loss. PMID:24808890

Systematic review of vestibular disorders related to human immunodeficiency virus and acquired immunodeficiency syndrome.

PubMed

Heinze, B; Swanepoel, D W; Hofmeyr, L M

2011-09-01

Disorders of the auditory and vestibular system are often associated with human immunodeficiency virus infection and acquired immunodeficiency syndrome. However, the extent and nature of these vestibular manifestations are unclear. To systematically review the current peer-reviewed literature on vestibular manifestations and pathology related to human immunodeficiency virus and acquired immunodeficiency syndrome. Systematic review of peer-reviewed articles related to vestibular findings in individuals with human immunodeficiency virus infection and acquired immunodeficiency syndrome. Several electronic databases were searched. We identified 442 records, reduced to 210 after excluding duplicates and reviews. These were reviewed for relevance to the scope of the study. We identified only 13 reports investigating vestibular functioning and pathology in individuals affected by human immunodeficiency virus and acquired immunodeficiency syndrome. This condition can affect both the peripheral and central vestibular system, irrespective of age and viral disease stage. Peripheral vestibular involvement may affect up to 50 per cent of patients, and central vestibular involvement may be even more prevalent. Post-mortem studies suggest direct involvement of the entire vestibular system, while opportunistic infections such as oto- and neurosyphilis and encephalitis cause secondary vestibular dysfunction resulting in vertigo, dizziness and imbalance. Patients with human immunodeficiency virus and acquired immunodeficiency syndrome should routinely be monitored for vestibular involvement, to minimise functional limitations of quality of life.

Gaba mediated long-term depression (LTD) in the rat medial vestibular nuclei.

PubMed

Grassi, S; Della Torre, G; Zampolini, M; Pettorossi, V E

1995-01-01

As previously demonstrated, high frequency stimulation (HFS) of the primary vestibular afferents always induces a clear, long lasting depression of the polysynaptic (N2) component of the field potentials recorded in the dorsal portion of the medial vestibular nuclei (MVN). The induction of the HFS effect was mediated by the activation of glutamate NMDA receptors, since it was blocked by AP5. The mechanisms at the basis of such a depression were studied. Our results demonstrate that Gaba, acting on both GabaA and GabaB receptors, is involved in mediating this phenomenon. In fact, HFS applied during Bicuculline and Saclofen perfusion, was no longer able to induce an N2 depression, but provoked a slight potentiation. However, the N2 depression clearly emerged after drug wash-out. Furthermore, Bicuculline and Saclofen fully abolished the N2 depression and highlighted the potentiation, when administered after HFS. The possibility that the N2 depression is the result of a homosynaptic LTD can be excluded on the basis of our results. On the contrary, our findings suggest that the depression is due to an enhancement of the Gaba inhibitory effect due to an HFS dependent increase in gabaergic interneuron activity, which resets vestibular neuron excitability at a lower level.

Regeneration of hair cells in the mammalian vestibular system.

PubMed

Li, Wenyan; You, Dan; Chen, Yan; Chai, Renjie; Li, Huawei

2016-06-01

Hair cells regenerate throughout the lifetime of non-mammalian vertebrates, allowing these animals to recover from hearing and balance deficits. Such regeneration does not occur efficiently in humans and other mammals. Thus, balance deficits become permanent and is a common sensory disorder all over the world. Since Forge and Warchol discovered the limited spontaneous regeneration of vestibular hair cells after gentamicininduced damage in mature mammals, significant efforts have been exerted to trace the origin of the limited vestibular regeneration in mammals after hair cell loss. Moreover, recently many strategies have been developed to promote the hair cell regeneration and subsequent functional recovery of the vestibular system, including manipulating the Wnt, Notch and Atoh1. This article provides an overview of the recent advances in hair cell regeneration in mammalian vestibular epithelia. Furthermore, this review highlights the current limitations of hair cell regeneration and provides the possible solutions to regenerate functional hair cells and to partially restore vestibular function.

AN ADENYLYL CYCLASE SIGNALING PATHWAY PREDICTS DIRECT DOPAMINERGIC INPUT TO VESTIBULAR HAIR CELLS

PubMed Central

DRESCHER, M. J.; CHO, W. J.; FOLBE, A. J.; SELVAKUMAR, D.; KEWSON, D. T.; ABU-HAMDAN, M. D.; OH, C. K.; RAMAKRISHNAN, N. A.; HATFIELD, J. S.; KHAN, K. M.; ANNE, S.; HARPOOL, E. C.; DRESCHER, D. G.

2010-01-01

Adenylyl cyclase signaling pathways have been identified in a model hair cell preparation from the trout saccule, for which the hair cell is the only intact cell type. The use of degenerate primers targeting cDNA sequence conserved across adenylyl cyclase (AC) isoforms, and RT-PCR, coupled with cloning of amplification products, indicated expression of AC9, AC7 and AC5/6, with cloning efficiencies of 11:5:2. AC9 and AC5/6 are inhibited by Ca2+, the former in conjunction with calcineurin, and message for calcineurin has also been identified in the trout saccular hair cell layer. AC7 is independent of Ca2+. Given the lack of detection of calcium/calmodulin-activated isoforms previously suggested to mediate adenylyl cyclase activation in the absence of Gαs in mammalian cochlear hair cells, the issue of hair-cell Gαs mRNA expression was re-examined in the teleost vestibular hair cell model. Two full-length coding sequences were obtained for Gαs/olf in the vestibular type II-like hair cells of the trout saccule. Two messages for Gαi have also been detected in the hair cell layer, one with homology to Gαi1 and the second with homology to Gαi3 of higher vertebrates. Both Gαs/olf protein and Gαi1/Gαi3 protein were immunolocalized to stereocilia and to the base of the hair cell, the latter consistent with sites of efferent input. While a signaling event coupling to Gαs/olf and Gαi1/Gαi3 in the stereocilia is currently unknown, signaling with Gαs/olf, Gαi3, and AC5/6 at the base of the hair cell would be consistent with transduction pathways activated by dopaminergic efferent input. mRNA for dopamine receptors D1A4 and five forms of dopamine D2 were found to be expressed in the teleost saccular hair cell layer, representing information on vestibular hair cell expression not directly available for higher vertebrates. Dopamine D1A receptor would couple to Gαolf and activation of AC5/6. Co-expression with dopamine D2 receptor, which itself couples to Gαi3 and AC5/6, will down-modulate levels of cAMP, thus fine-tuning and gradating the hair-cell response to dopamine D1A. As predicted by the trout saccular hair cell model, evidence has been obtained for the first time that hair cells of mammalian otolithic vestibular end organs (rat/mouse saccule/utricle) express dopamine D1A and D2L receptors, and each receptor co-localizes with AC5/6, with a marked presence of all three proteins in subcuticular regions of type I vestibular hair cells. A putative efferent, presynaptic source of dopamine was identified in tyrosine hydroxylase-positive nerve fibers which passed from underlying connective tissue to the sensory epithelia, ending on type I and type II vestibular hair cells and on afferent calyces. PMID:20883745

An adenylyl cyclase signaling pathway predicts direct dopaminergic input to vestibular hair cells.

PubMed

Drescher, M J; Cho, W J; Folbe, A J; Selvakumar, D; Kewson, D T; Abu-Hamdan, M D; Oh, C K; Ramakrishnan, N A; Hatfield, J S; Khan, K M; Anne, S; Harpool, E C; Drescher, D G

2010-12-29

Adenylyl cyclase (AC) signaling pathways have been identified in a model hair cell preparation from the trout saccule, for which the hair cell is the only intact cell type. The use of degenerate primers targeting cDNA sequence conserved across AC isoforms, and reverse transcription-polymerase chain reaction (RT-PCR), coupled with cloning of amplification products, indicated expression of AC9, AC7 and AC5/6, with cloning efficiencies of 11:5:2. AC9 and AC5/6 are inhibited by Ca(2+), the former in conjunction with calcineurin, and message for calcineurin has also been identified in the trout saccular hair cell layer. AC7 is independent of Ca(2+). Given the lack of detection of calcium/calmodulin-activated isoforms previously suggested to mediate AC activation in the absence of Gαs in mammalian cochlear hair cells, the issue of hair-cell Gαs mRNA expression was re-examined in the teleost vestibular hair cell model. Two full-length coding sequences were obtained for Gαs/olf in the vestibular type II-like hair cells of the trout saccule. Two messages for Gαi have also been detected in the hair cell layer, one with homology to Gαi1 and the second with homology to Gαi3 of higher vertebrates. Both Gαs/olf protein and Gαi1/Gαi3 protein were immunolocalized to stereocilia and to the base of the hair cell, the latter consistent with sites of efferent input. Although a signaling event coupling to Gαs/olf and Gαi1/Gαi3 in the stereocilia is currently unknown, signaling with Gαs/olf, Gαi3, and AC5/6 at the base of the hair cell would be consistent with transduction pathways activated by dopaminergic efferent input. mRNA for dopamine receptors D1A4 and five forms of dopamine D2 were found to be expressed in the teleost saccular hair cell layer, representing information on vestibular hair cell expression not directly available for higher vertebrates. Dopamine D1A receptor would couple to Gαolf and activation of AC5/6. Co-expression with dopamine D2 receptor, which itself couples to Gαi3 and AC5/6, will down-modulate levels of cAMP, thus fine-tuning and gradating the hair-cell response to dopamine D1A. As predicted by the trout saccular hair cell model, evidence has been obtained for the first time that hair cells of mammalian otolithic vestibular end organs (rat/mouse saccule/utricle) express dopamine D1A and D2L receptors, and each receptor co-localizes with AC5/6, with a marked presence of all three proteins in subcuticular regions of type I vestibular hair cells. A putative efferent, presynaptic source of dopamine was identified in tyrosine hydroxylase-positive nerve fibers which passed from underlying connective tissue to the sensory epithelia, ending on type I and type II vestibular hair cells and on afferent calyces. Copyright © 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

Consequences and assessment of human vestibular failure: implications for postural control.

PubMed

Colebatch, James G

2002-01-01

Labyrinthine afferents respond to both angular velocity (semicircular canals) and linear acceleration (otoliths), including gravity. Given their response to gravity, the otoliths are likely to have an important role in the postural functions of the vestibular apparatus. Unilateral vestibular ablation has dramatic effects on posture in many animals, but less so in primates. Nevertheless, bilateral vestibular lesions lead to disabling symptoms in man related to disturbed ocular and postural control and impaired perception of slopes and accelerations. While seimicircular canal function can be assessed through its effects on vestibular ocular reflexes, assessment of otolith function in man has traditionally been much more difficult. Recent definition of a short latency vestibulocollic reflex, activated by sound and appearing to arise from the saccule, shows promise as a new method of non-invasive assessment of otolith function.

Selective skin sensitivity changes and sensory reweighting following short-duration space flight.

PubMed

Lowrey, Catherine R; Perry, Stephen D; Strzalkowski, Nicholas D J; Williams, David R; Wood, Scott J; Bent, Leah R

2014-03-15

Skin sensory input from the foot soles is coupled with vestibular input to facilitate body orientation in a gravitational environment. Anecdotal observations suggest that foot sole skin becomes hypersensitive following space flight. The veritable level of skin sensitivity and its impact on postural disequilibrium observed post space flight have not been documented. Skin sensitivity of astronauts (n = 11) was measured as vibration perception at the great toe, fifth metatarsal and heel. Frequencies targeted four classes of receptors: 3 and 25 Hz for slow-adapting (SA) receptors and 60 and 250 Hz for fast-adapting (FA) receptors. Data were collected pre- and post-space flight. We hypothesized that skin sensitivity would increase post-space flight and correlate to balance measures. Decreased skin sensitivity was found on landing day at 3 and 25 Hz on the great toe. Hypersensitivity was found for a subset of astronauts (n = 6) with significantly increased sensitivity to 250 Hz at the heel. This subset displayed a greater reduction in computerized dynamic posturography (CDP) equilibrium (EQ) scores (-54%) on landing vs. non-hypersensitive participants (-11%). Observed hyposensitivity of SA (pressure) receptors may indicate a strategy to reduce pressure input during periods of unloading. Hypersensitivity of FAs coupled with reduced EQ scores may reflect targeted sensory reweighting. Altered gravito-inertial environments reduce vestibular function in balance control which may trigger increased weighting of FAs (that signal foot contact, slips). Understanding modulations to skin sensitivity has translational implications for mitigating postural disequilibrium following space flight and for on-Earth preventative strategies for imbalance in older adults.

Postural compensation for vestibular loss and implications for rehabilitation.

PubMed

Horak, Fay B

2010-01-01

This chapter summarizes the role of the vestibular system in postural control so that specific and effective rehabilitation can be designed that facilitates compensation for loss of vestibular function. Patients with bilateral or unilateral loss of peripheral vestibular function are exposed to surface perturbations to quantify automatic postural responses. Studies also evaluated the effects of audio- and vibrotactile-biofeedback to improve stability in stance and gait. The most important role of vestibular information for postural control is to control orientation of the head and trunk in space with respect to gravitoinertial forces, particularly when balancing on unstable surfaces. Vestibular sensory references are particularly important for postural control at high frequencies and velocities of self-motion, to reduce trunk drift and variability, to provide an external reference frame for the trunk and head in space; and to uncouple coordination of the trunk from the legs and the head-in-space from the body CoM. The goal of balance rehabilitation for patients with vestibular loss is to help patients 1) use remaining vestibular function, 2) depend upon surface somatosensory information as their primary postural sensory system, 3) learn to use stable visual references, and 4) identify efficient and effective postural movement strategies.

Large basolateral processes on type II hair cells comprise a novel processing unit in mammalian vestibular organs

PubMed Central

Pujol, Rémy; Pickett, Sarah B.; Nguyen, Tot Bui; Stone, Jennifer S.

2014-01-01

Sensory receptors in the vestibular system (hair cells) encode head movements and drive central motor reflexes that control gaze, body movements, and body orientation. In mammals, type I and II vestibular hair cells are defined by their shape, contacts with vestibular afferent nerves, and membrane conductance. Here, we describe unique morphological features of type II vestibular hair cells in mature rodents (mice and gerbils) and bats. These features are cytoplasmic processes that extend laterally from the hair cell’s base and project under type I hair cells. Closer analysis of adult mouse utricles demonstrated that the basolateral processes of type II hair cells range in shape, size, and branching, with the longest processes extending 3–4 hair cell widths. The hair cell basolateral processes synapse upon vestibular afferent nerves and receive inputs from vestibular efferent nerves. Further, some basolateral processes make physical contacts with the processes of other type II hair cells, forming some sort of network amongst type II hair cells. Basolateral processes are rare in perinatal mice and do not attain their mature form until 3–6 weeks of age. These observations demonstrate that basolateral processes are significant signaling regions of type II vestibular hair cells, and they suggest type II hair cells may directly communicate with each other, which has not been described in vertebrates. PMID:24825750

Large basolateral processes on type II hair cells are novel processing units in mammalian vestibular organs.

PubMed

Pujol, Rémy; Pickett, Sarah B; Nguyen, Tot Bui; Stone, Jennifer S

2014-10-01

Sensory receptors in the vestibular system (hair cells) encode head movements and drive central motor reflexes that control gaze, body movements, and body orientation. In mammals, type I and II vestibular hair cells are defined by their shape, contacts with vestibular afferent nerves, and membrane conductance. Here we describe unique morphological features of type II vestibular hair cells in mature rodents (mice and gerbils) and bats. These features are cytoplasmic processes that extend laterally from the hair cell base and project under type I hair cells. Closer analysis of adult mouse utricles demonstrated that the basolateral processes of type II hair cells vary in shape, size, and branching, with the longest processes extending three to four hair cell widths. The hair cell basolateral processes synapse upon vestibular afferent nerves and receive inputs from vestibular efferent nerves. Furthermore, some basolateral processes make physical contacts with the processes of other type II hair cells, forming some sort of network among type II hair cells. Basolateral processes are rare in perinatal mice and do not attain their mature form until 3-6 weeks of age. These observations demonstrate that basolateral processes are significant signaling regions of type II vestibular hair cells and suggest that type II hair cells may directly communicate with each other, which has not been described in vertebrates. © 2014 Wiley Periodicals, Inc.

Short latency compound action potentials from mammalian gravity receptor organs

NASA Technical Reports Server (NTRS)

Jones, T. A.; Jones, S. M.

1999-01-01

Gravity receptor function was characterized in four mammalian species using far-field vestibular evoked potentials (VsEPs). VsEPs are compound action potentials of the vestibular nerve and central relays that are elicited by linear acceleration ramps applied to the cranium. Rats, mice, guinea pigs, and gerbils were studied. In all species, response onset occurred within 1.5 ms of the stimulus onset. Responses persisted during intense (116 dBSPL) wide-band (50 to 50 inverted question mark omitted inverted question mark000 Hz) forward masking, whereas auditory responses to intense clicks (112 dBpeSPL) were eliminated under the same conditions. VsEPs remained after cochlear extirpation but were eliminated following bilateral labyrinthectomy. Responses included a series of positive and negative peaks that occurred within 8 ms of stimulus onset (range of means at +6 dBre: 1.0 g/ms: P1=908 to 1062 micros, N1=1342 to 1475 micros, P2=1632 to 1952 micros, N2=2038 to 2387 micros). Mean response amplitudes at +6 dBre: 1.0 g/ms ranged from 0.14 to 0.99 microV. VsEP input/output functions revealed latency slopes that varied across peaks and species ranging from -19 to -51 micros/dB. Amplitude-intensity slopes also varied ranging from 0.04 to 0.08 microV/dB for rats and mice. Latency values were comparable to those of birds although amplitudes were substantially smaller in mammals. VsEP threshold values were considerably higher in mammals compared to birds and ranged from -8.1 to -10.5 dBre 1.0 g/ms across species. These results support the hypothesis that mammalian gravity receptors are less sensitive to dynamic stimuli than are those of birds.

The adequate stimulus for mammalian linear vestibular evoked potentials (VsEPs)

PubMed Central

Jones, Timothy A.; Jones, Sherri M.; Vijayakumar, Sarath; Brugeaud, Aurore; Bothwell, Marcella; Chabbert, Christian

2013-01-01

Short latency linear vestibular sensory evoked potentials (VsEPs) provide a means to objectively and directly assess the function of gravity receptors in mammals and birds. The importance of this functional measure is illustrated by its use in studies of the genetic basis of vestibular function and disease. Head motion is the stimulus for the VsEP. In the bird, it has been established that neurons mediating the linear VsEP respond collectively to the rate of change in linear acceleration during head movement (i.e. jerk) rather than peak acceleration. The kinematic element of motion responsible for triggering mammalian VsEPs has not been characterized in detail. Here we tested the hypothesis that jerk is the kinematic component of head motion responsible for VsEP characteristics. VsEP amplitudes and latencies changed systematically when peak acceleration level was held constant and jerk level was varied from ~0.9 to 4.6 g/ms. In contrast, responses remained relatively constant when kinematic jerk was held constant and peak acceleration was varied from ~0.9 to 5.5g in mice and ~0.44 to 2.75g in rats. Thus the mammalian VsEP depends on jerk levels and not peak acceleration. We conclude that kinematic jerk is the adequate stimulus for the mammalian VsEP. This sheds light on the behavior of neurons generating the response. The results also provide the basis for standardizing the reporting of stimulus levels, which is key to ensuring that response characteristics reported in the literature by many laboratories can be effectively compared and interpreted. PMID:21664446

Interaction between Vestibular Compensation Mechanisms and Vestibular Rehabilitation Therapy: 10 Recommendations for Optimal Functional Recovery

PubMed Central

Lacour, Michel; Bernard-Demanze, Laurence

2015-01-01

This review questions the relationships between the plastic events responsible for the recovery of vestibular function after a unilateral vestibular loss (vestibular compensation), which has been well described in animal models in the last decades, and the vestibular rehabilitation (VR) therapy elaborated on a more empirical basis for vestibular loss patients. The main objective is not to propose a catalog of results but to provide clinicians with an understandable view on when and how to perform VR therapy, and why VR may benefit from basic knowledge and may influence the recovery process. With this perspective, 10 major recommendations are proposed as ways to identify an optimal functional recovery. Among them are the crucial role of active and early VR therapy, coincidental with a post-lesion sensitive period for neuronal network remodeling, the instructive role that VR therapy may play in this functional reorganization, the need for progression in the VR therapy protocol, which is based mainly on adaptation processes, the necessity to take into account the sensorimotor, cognitive, and emotional profile of the patient to propose individual or “à la carte” VR therapies, and the importance of motivational and ecologic contexts. More than 10 general principles are very likely, but these principles seem crucial for the fast recovery of vestibular loss patients to ensure good quality of life. PMID:25610424

Vertigo Perception and Quality of Life in Patients after Surgical Treatment of Vestibular Schwannoma with Pretreatment Prehabituation by Chemical Vestibular Ablation

PubMed Central

Balatková, Zuzana; Chovanec, Martin; Čakrt, Ondřej; Hrubá, Silvie; Jeřábek, Jaroslav; Zvěřina, Eduard; Profant, Oliver; Fík, Zdeněk; Komarc, Martin; Kluh, Jan; Černý, Rudolf

2016-01-01

Surgical removal of vestibular schwannoma causes acute vestibular symptoms, including postoperative vertigo and oscillopsia due to nystagmus. In general, the dominant symptom postoperatively is vertigo. Preoperative chemical vestibular ablation can reduce vestibular symptoms postoperatively. We used 1.0 mL of 40 mg/mL nonbuffered gentamicin in three intratympanic installations over 2 days, 2 months preoperatively in 10 patients. Reduction of vestibular function was measured by the head impulse test and the caloric test. Reduction of vestibular function was found in all gentamicin patient groups. After gentamicin vestibular ablation, patients underwent home vestibular exercising for two months. The control group consisted of 10 patients who underwent only home vestibular training two months preoperatively. Postoperative rates of recovery and vertigo in both groups were evaluated with the Glasgow Benefit Inventory (GBI), the Glasgow Health Status Inventory (GHSI), and the Dizziness Handicap Inventory questionnaires, as well as survey of visual symptoms by specific questionnaire developed by us. There were no statistically significant differences between both groups with regard to the results of questionnaires. Patients who received preoperative gentamicin were more resilient to optokinetic and optic flow stimulation (p < 0.05). This trial is registered with clinical study registration number NCT02963896. PMID:28053986

Vertigo Perception and Quality of Life in Patients after Surgical Treatment of Vestibular Schwannoma with Pretreatment Prehabituation by Chemical Vestibular Ablation.

PubMed

Čada, Zdeněk; Balatková, Zuzana; Chovanec, Martin; Čakrt, Ondřej; Hrubá, Silvie; Jeřábek, Jaroslav; Zvěřina, Eduard; Profant, Oliver; Fík, Zdeněk; Komarc, Martin; Betka, Jan; Kluh, Jan; Černý, Rudolf

2016-01-01

Surgical removal of vestibular schwannoma causes acute vestibular symptoms, including postoperative vertigo and oscillopsia due to nystagmus. In general, the dominant symptom postoperatively is vertigo. Preoperative chemical vestibular ablation can reduce vestibular symptoms postoperatively. We used 1.0 mL of 40 mg/mL nonbuffered gentamicin in three intratympanic installations over 2 days, 2 months preoperatively in 10 patients. Reduction of vestibular function was measured by the head impulse test and the caloric test. Reduction of vestibular function was found in all gentamicin patient groups. After gentamicin vestibular ablation, patients underwent home vestibular exercising for two months. The control group consisted of 10 patients who underwent only home vestibular training two months preoperatively. Postoperative rates of recovery and vertigo in both groups were evaluated with the Glasgow Benefit Inventory (GBI), the Glasgow Health Status Inventory (GHSI), and the Dizziness Handicap Inventory questionnaires, as well as survey of visual symptoms by specific questionnaire developed by us. There were no statistically significant differences between both groups with regard to the results of questionnaires. Patients who received preoperative gentamicin were more resilient to optokinetic and optic flow stimulation ( p < 0.05). This trial is registered with clinical study registration number NCT02963896.

Effects of Saccular Function on Recovery of Subjective Dizziness After Vestibular Rehabilitation.

PubMed

Jeong, Junhui; Jung, Jinsei; Lee, Jeon Mi; Suh, Michelle J; Kwak, Sang Hyun; Kim, Sung Huhn

2017-08-01

We attempted to investigate whether the integrity of saccular function influences the severity of subjective dizziness after vestibular rehabilitation in vestibular neuritis. Retrospective analysis. Tertiary referral center. Forty-six patients with acute unilateral vestibular neuritis were included. Diagnostic, therapeutic, and rehabilitative. All the patients completed vestibular rehabilitation therapy until their computerized dynamic posturography and rotary chair test results were significantly improved. The rehabilitation patients were classified into the normal to mild subjective dizziness and moderate to severe subjective dizziness groups according to the dizziness handicap inventory score (cutoff of 40). Differences between the two groups were analyzed. After rehabilitation, 32.6% of the patients still complained of moderate to severe dizziness. Age, sex distribution, the presence of comorbidities, caloric weakness, pre- and postrehabilitation gain values in rotary chair test, postrehabilitation composite scores in posturography, and the duration of rehabilitation were not significantly different between the two groups. However, initial dizziness handicap inventory (DHI) score and composite score in dynamic posturography were worse and the proportion of patients with absent cervical vestibular-evoked myogenic potential in the moderate to severe group was much higher (93.3% vs. 35.5%, p < 0.001). After multiple regression analysis of those factors, initial DHI score and absent cervical vestibular-evoked myogenic potential response were identified as being associated with higher postrehabilitation DHI score. Saccular dysfunction in acute vestibular neuritis can contribute to persistent subjective dizziness, even after the objective parameters of vestibular function tests have been improved by vestibular rehabilitation.

Developmental shift from long-term depression to long-term potentiation in the rat medial vestibular nuclei: role of group I metabotropic glutamate receptors.

PubMed

Puyal, Julien; Grassi, Silvarosa; Dieni, Cristina; Frondaroli, Adele; Demêmes, Danielle; Raymond, Jaqueline; Pettorossi, Vito Enrico

2003-12-01

The effects of high frequency stimulation (HFS) of the primary vestibular afferents on synaptic transmission in the ventral part of the medial vestibular nuclei (vMVN) were studied during postnatal development and compared with the changes in the expression of the group I metabotropic glutamate receptor (mGluR) subtypes, mGluR1 and mGluR5. During the first stages of development, HFS always induced a mGluR5- and GABAA-dependent long-term depression (LTD) which did not require NMDA receptor and mGluR1 activation. The probability of inducing LTD decreased progressively throughout the development and it was zero at about the end of the second postnatal week. Conversely, long-term potentiation (LTP) appeared at the beginning of the second week and its occurrence increased to reach the adult value at the end of the third week. Of interest, the sudden change in the LTP frequency occurred at the time of eye opening, about the end of the second postnatal week. LTP depended on NMDA receptor and mGluR1 activation. In parallel with the modifications in synaptic plasticity, we observed that the expression patterns and localizations of mGluR5 and mGluR1 in the medial vestibular nuclei (MVN) changed during postnatal development. At the earlier stages the mGluR1 expression was minimal, then increased progressively. In contrast, mGluR5 expression was initially high, then decreased. While mGluR1 was exclusively localized in neuronal compartments and concentrated at the postsynaptic sites at all stages observed, mGluR5 was found mainly in neuronal compartments at immature stages, then preferentially in glial compartments at mature stages. These results provide the first evidence for a progressive change from LTD to LTP accompanied by a distinct maturation expression of mGluR1 and mGluR5 during the development of the MVN.

Influence of combined visual and vestibular cues on human perception and control of horizontal rotation

NASA Technical Reports Server (NTRS)

Zacharias, G. L.; Young, L. R.

1981-01-01

Measurements are made of manual control performance in the closed-loop task of nulling perceived self-rotation velocity about an earth-vertical axis. Self-velocity estimation is modeled as a function of the simultaneous presentation of vestibular and peripheral visual field motion cues. Based on measured low-frequency operator behavior in three visual field environments, a parallel channel linear model is proposed which has separate visual and vestibular pathways summing in a complementary manner. A dual-input describing function analysis supports the complementary model; vestibular cues dominate sensation at higher frequencies. The describing function model is extended by the proposal of a nonlinear cue conflict model, in which cue weighting depends on the level of agreement between visual and vestibular cues.

Estimation of an Optimal Stimulus Amplitude for Using Vestibular Stochastic Stimulation to Improve Balance Function

NASA Technical Reports Server (NTRS)

Goel, R.; Kofman, I.; DeDios, Y. E.; Jeevarajan, J.; Stepanyan, V.; Nair, M.; Congdon, S.; Fregia, M.; Peters, B.; Cohen, H.;

Normal and abnormal human vestibular ocular function

NASA Technical Reports Server (NTRS)

Peterka, R. J.; Black, F. O.

1986-01-01

The major motivation of this research is to understand the role the vestibular system plays in sensorimotor interactions which result in spatial disorientation and motion sickness. A second goal was to explore the range of abnormality as it is reflected in quantitative measures of vestibular reflex responses. The results of a study of vestibular reflex measurements in normal subjects and preliminary results in abnormal subjects are presented in this report. Statistical methods were used to define the range of normal responses, and determine age related changes in function.

Current evidence of peripheral vestibular symptoms secondary to otitis media.

PubMed

Monsanto, Rafael da Costa; Kasemodel, Ana Luiza Papi; Tomaz, Andreza; Paparella, Michael M; Penido, Norma de Oliveira

2018-05-06

The association between otitis media and vestibular symptoms has been hypothesized in the past. Thus, in this study, we aimed to critically analyze (based in a systematic review of the literature) whether patients who have otitis media are at greater risk of developing vestibular impairment or not. We performed a systematic review of the literature and identified potentially relevant articles reporting vestibular symptoms and results of vestibular function tests in patients with otitis media through searches of the PubMED, Web of Science, Scopus, and Google Scholar databases. The quality of the final set of records was assessed using the "Newcaste-Ottawa Scale". Of the 2334 records searched, 43 met our inclusion and exclusion criteria, and those included 2250 patients. The records comprised 20 longitudinal studies, 21 cross-sectional studies, and 2 case reports. Regarding the type of otitis media studied, 25 examined vestibular impairment in otitis media with effusion, 6 acute otitis media, and 12 chronic otitis media. Results of anamnesis, clinical exams, and several vestibular function tests are reported and critically discussed. Most studies evaluating the association between otitis media and vestibular symptoms have potential methodological flaws. Clinical evidence suggests that patients with otitis media have increased chances for having vestibular symptoms, delayed acquisition of developmental milestones, and abnormalities in several vestibular function tests as compared with controls. Future studies with rigorous methodology aiming to assess the clinical significance (and prognostic factors) of the association between otitis media and vestibular impairment are warranted. Key message Several studies demonstrated long-term sequelae secondary to otitis media. However, the evidence supporting those assumptions are based in low-quality evidence. Thus, better structured studies are warranted to better understand the clinical relevance of such association.

Differential central projections of vestibular afferents in pigeons

NASA Technical Reports Server (NTRS)

Dickman, J. D.; Fang, Q.

1996-01-01

The question of whether a differential distribution of vestibular afferent information to central nuclear neurons is present in pigeons was studied using neural tracer compounds. Discrete tracing of afferent fibers innervating the individual semicircular canal and otolith organs was produced by sectioning individual branches of the vestibular nerve that innervate the different receptor organs and applying crystals of horseradish peroxidase, or a horseradish peroxidase/cholera toxin mixture, or a biocytin compound for neuronal uptake and transport. Afferent fibers and their terminal distributions within the brainstem and cerebellum were visualized subsequently. Discrete areas in the pigeon central nervous system that receive primary vestibular input include the superior, dorsal lateral, ventral lateral, medial, descending, and tangential vestibular nuclei; the A and B groups; the intermediate, medial, and lateral cerebellar nuclei; and the nodulus, the uvula, and the paraflocculus. Generally, the vertical canal afferents projected heavily to medial regions in the superior and descending vestibular nuclei as well as the A group. Vertical canal projections to the medial and lateral vestibular nuclei were observed but were less prominent. Horizontal canal projections to the superior and descending vestibular nuclei were much more centrally located than those of the vertical canals. A more substantial projection to the medial and lateral vestibular nuclei was seen with horizontal canal afferents compared to vertical canal fibers. Afferents innervating the utricle and saccule terminated generally in the lateral regions of all vestibular nuclei in areas that were separate from the projections of the semicircular canals. In addition, utricular fibers projected to regions in the vestibular nuclei that overlapped with the horizontal semicircular canal terminal fields, whereas saccular afferents projected to regions that received vertical canal fiber terminations. Lagenar afferents projected throughout the cochlear nuclei, to the dorsolateral regions of the cerebellar nuclei, and to lateral regions of the superior, lateral, medial, and descending vestibular nuclei.

Loss of α-calcitonin gene-related peptide (αCGRP) reduces the efficacy of the Vestibulo-ocular Reflex (VOR).

PubMed

Luebke, Anne E; Holt, Joseph C; Jordan, Paivi M; Wong, Yi Shan; Caldwell, Jillian S; Cullen, Kathleen E

2014-07-30

The neuroactive peptide calcitonin-gene related peptide (CGRP) is known to act at efferent synapses and their targets in hair cell organs, including the cochlea and lateral line. CGRP is also expressed in vestibular efferent neurons as well as a number of central vestibular neurons. Although CGRP-null (-/-) mice demonstrate a significant reduction in cochlear nerve sound-evoked activity compared with wild-type mice, it is unknown whether and how the loss of CGRP influence vestibular system function. Vestibular function was assessed by quantifying the vestibulo-ocular reflex (VOR) in alert mice. The loss of CGRP in (-/-) mice was associated with a reduction of the VOR gain of ≈50% without a concomitant change in phase. Using immunohistochemistry, we confirmed that, although CGRP staining was absent in the vestibular end-organs of null (-/-) mice, cholinergic staining appeared normal, suggesting that the overall gross development of vestibular efferent innervation was unaltered. We further confirmed that the observed deficit in vestibular function of null (-/-) mice was not the result of nontargeted effects at the level of the extraocular motor neurons and/or their innervation of extraocular muscles. Analysis of the relationship between vestibular quick phase amplitude and peak velocity revealed that extraocular motor function was unchanged, and immunohistochemistry revealed no abnormalities in motor endplates. Together, our findings show that the neurotransmitter CGRP plays a key role in ensuring VOR efficacy. Copyright © 2014 the authors 0270-6474/14/3410453-06$15.00/0.

Preliminary evidence of improved cognitive performance following vestibular rehabilitation in children with combined ADHD (cADHD) and concurrent vestibular impairment.

PubMed

Lotfi, Younes; Rezazadeh, Nima; Moossavi, Abdollah; Haghgoo, Hojjat Allah; Rostami, Reza; Bakhshi, Enayatollah; Badfar, Faride; Moghadam, Sedigheh Farokhi; Sadeghi-Firoozabadi, Vahid; Khodabandelou, Yousef

2017-12-01

Balance function has been reported to be worse in ADHD children than in their normal peers. The present study hypothesized that an improvement in balance could result in better cognitive performance in children with ADHD and concurrent vestibular impairment. This study was designed to evaluate the effects of comprehensive vestibular rehabilitation therapy on the cognitive performance of children with combined ADHD and concurrent vestibular impairment. Subject were 54 children with combined ADHD. Those with severe vestibular impairment (n=33) were randomly assigned to two groups that were matched for age. A rehabilitation program comprising overall balance and gate, postural stability, and eye movement exercises was assigned to the intervention group. Subjects in the control group received no intervention for the same time period. Intervention was administered twice weekly for 12 weeks. Choice reaction time (CRT) and spatial working memory (SWM) subtypes of the Cambridge Neuropsychological Test Automated Battery (CANTAB) were completed pre- and post-intervention to determine the effects of vestibular rehabilitation on the cognitive performance of the subjects with ADHD and concurrent vestibular impairment. ANCOVA was used to compare the test results of the intervention and control group post-test. The percentage of correct trial scores for the CRT achieved by the intervention group post-test increased significantly compared to those of the control group (p=0.029). The CRT mean latency scores were significantly prolonged in the intervention group following intervention (p=0.007) compared to the control group. No significant change was found in spatial functioning of the subjects with ADHD following 12 weeks of intervention (p>0.05). The study highlights the effect of vestibular rehabilitation on the cognitive performance of children with combined ADHD and concurrent vestibular disorder. The findings indicate that attention can be affected by early vestibular rehabilitation, which is a basic program for improving memory function in such children. Appropriate vestibular rehabilitation programs based on the type of vestibular impairment of children can improve their cognitive ability to some extent in children with ADHD and concurrent vestibular impairment (p>0.05). Copyright © 2017 Elsevier B.V. All rights reserved.

Student-involved demonstration approach to teach the physiology of vestibular apparatus for undergraduate medical students.

PubMed

Narayanan, Sareesh Naduvil; Kumar, Raju Suresh; Nayak, Satheesha

2011-01-01

It is quite difficult to teach complex topics like the physiology of vestibular apparatus to undergraduate students. Understanding the orientation and mode of stimulation of receptors in vestibular apparatus is also quite challenging for the students. As faculty we attempt to use innovative methods to teach physiology and enhance student learning. This article describes a simple and innovative method (student-involved demonstration approach, or SID) to teach the physiology of the vestibular apparatus to the undergraduate medical students. The current study describes a protocol where students engage in role-play sessions in the middle of the regular didactic lectures. Effectiveness of the sessions was later evaluated by using a questionnaire and by comparing the pre-SID and post-SID test results of the students. The posttest score of the students was significantly higher than the pretest score, and this indicates the usefulness of SID sessions on enhancing the student learning in the class. Students also found this method very interesting and useful in better understanding the physiology of the vestibular apparatus.

PLCγ-activated signalling is essential for TrkB mediated sensory neuron structural plasticity

PubMed Central

2010-01-01

Background The vestibular system provides the primary input of our sense of balance and spatial orientation. Dysfunction of the vestibular system can severely affect a person's quality of life. Therefore, understanding the molecular basis of vestibular neuron survival, maintenance, and innervation of the target sensory epithelia is fundamental. Results Here we report that a point mutation at the phospholipase Cγ (PLCγ) docking site in the mouse neurotrophin tyrosine kinase receptor TrkB (Ntrk2) specifically impairs fiber guidance inside the vestibular sensory epithelia, but has limited effects on the survival of vestibular sensory neurons and growth of afferent processes toward the sensory epithelia. We also show that expression of the TRPC3 cation calcium channel, whose activity is known to be required for nerve-growth cone guidance induced by brain-derived neurotrophic factor (BDNF), is altered in these animals. In addition, we find that absence of the PLCγ mediated TrkB signalling interferes with the transformation of bouton type afferent terminals of vestibular dendrites into calyces (the largest synaptic contact of dendrites known in the mammalian nervous system) on type I vestibular hair cells; the latter are normally distributed in these mutants as revealed by an unaltered expression pattern of the potassium channel KCNQ4 in these cells. Conclusions These results demonstrate a crucial involvement of the TrkB/PLCγ-mediated intracellular signalling in structural aspects of sensory neuron plasticity. PMID:20932311

Differential effects of galvanic vestibular stimulation on arm position sense in right- vs. left-handers.

PubMed

Schmidt, Lena; Artinger, Frank; Stumpf, Oliver; Kerkhoff, Georg

2013-04-01

The human brain is organized asymmetrically in two hemispheres with different functional specializations. Left- and right-handers differ in many functional capacities and their anatomical representations. Right-handers often show a stronger functional lateralization than left-handers, the latter showing a more bilateral, symmetrical brain organization. Recent functional imaging evidence shows a different lateralization of the cortical vestibular system towards the side of the preferred hand in left- vs. right-handers as well. Since the vestibular system is involved in somatosensory processing and the coding of body position, vestibular stimulation should affect such capacities differentially in left- vs. right-handers. In the present, sham-stimulation-controlled study we explored this hypothesis by studying the effects of galvanic vestibular stimulation (GVS) on proprioception in both forearms in left- and right-handers. Horizontal arm position sense (APS) was measured with an opto-electronic device. Second, the polarity-specific online- and after-effects of subsensory, bipolar GVS on APS were investigated in different sessions separately for both forearms. At baseline, both groups did not differ in their unsigned errors for both arms. However, right-handers showed significant directional errors in APS of both arms towards their own body. Right-cathodal/left-anodal GVS, resulting in right vestibular cortex activation, significantly deteriorated left APS in right-handers, but had no detectable effect on APS in left-handers in either arm. These findings are compatible with a right-hemisphere dominance for vestibular functions in right-handers and a differential vestibular organization in left-handers that compensates for the disturbing effects of GVS on APS. Moreover, our results show superior arm proprioception in left-handers in both forearms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Visual Vestibular Interaction in the Dynamic Visual Acuity Test during Voluntary Head Rotation

NASA Technical Reports Server (NTRS)

Lee, Moo Hoon; Durnford, Simon; Crowley, John; Rupert, Angus

1996-01-01

Although intact vestibular function is essential in maintaining spatial orientation, no good screening tests of vestibular function are available to the aviation community. High frequency voluntary head rotation was selected as a vestibular stimulus to isolate the vestibulo-ocular reflex (VOR) from visual influence. A dynamic visual acuity test that incorporates voluntary head rotation was evaluated as a potential vestibular function screening tool. Twenty-seven normal subjects performed voluntary sinusoidal head rotation at frequencies from 0.7-4.0 Hz under three different visual conditions: visually-enhanced VOR, normal VOR, and visually suppressed VOR. Standardized Baily-Lovie chart letters were presented on a computer monitor in front of the subject, who then was asked to read the letters while rotating his head horizontally. The electro-oculogram and dynamic visual acuity score were recorded and analyzed. There were no significant differences in gain or phase shift among three visual conditions in the frequency range of 2.8 to 4.0 Hz. The dynamic visual acuity score shifted less than 0.3 logMAR at frequencies under 2.0 Hz. The dynamic visual acuity test at frequencies a round 2.0 Hz can be recommended for evaluating vestibular function.

The Dizziness Handicap Inventory does not correlate with vestibular function tests: a prospective study.

PubMed

Yip, Chun Wai; Strupp, Michael

2018-05-01

The Dizziness Handicap Inventory (DHI) is believed to quantitate the handicap related to the presence or severity of underlying vestibular dysfunction. However, patients with chronic vestibular diseases may manifest various degrees of behavioural and physiological adaptation resulting in variances of the DHI. Our primary study objective is to evaluate the correlation between the DHI and measurable vestibular parameters. Secondarily, we compared DHI among different vestibular disorders (central, peripheral and functional), and different types of anatomic deficits (semicircular canal vs otolithic). We also correlated the DHI and posturography. We prospectively evaluated 799 patients with precise vestibular diagnoses using video head impulse testing (vHIT), caloric irrigation, and cervical/ocular vestibular-evoked myogenic potentials (c/oVEMP). Posturography was done for 84 patients. All participants completed the DHI. No significant correlation was found between DHI and (1) vestibulo-ocular reflex parameters: unilateral weakness r = - 0.018, total calorics r = 0.055, vHIT right r = 0.007, vHIT left r = - 0.091, vHIT asymmetry r = 0.013; (2) otolith parameters: cVEMP amplitude right r = - 0.034, amplitude left r = - 0.004, asymmetry r = 0.016; oVEMP amplitude right r = 0.044, amplitude left r = - 0.007, asymmetry r = - 0.008. Patients with central vestibular disorders had higher DHI than those with peripheral (z = - 4.743, p = 0.001) or functional disorders (z = - 2.902, p = 0.004). DHI of patients with deficits of canal or otolith function did not differ significantly from those with no deficits (z = 2.153, p = 0.541). There was no significant correlation between DHI and postural sway on posturography. Therefore, the DHI does not correlate with vestibular tests, and neither reflects the presence nor severity of peripheral vestibular deficits.

Asymmetric vestibular stimulation reveals persistent disruption of motion perception in unilateral vestibular lesions.

PubMed

Panichi, R; Faralli, M; Bruni, R; Kiriakarely, A; Occhigrossi, C; Ferraresi, A; Bronstein, A M; Pettorossi, V E

2017-11-01

Self-motion perception was studied in patients with unilateral vestibular lesions (UVL) due to acute vestibular neuritis at 1 wk and 4, 8, and 12 mo after the acute episode. We assessed vestibularly mediated self-motion perception by measuring the error in reproducing the position of a remembered visual target at the end of four cycles of asymmetric whole-body rotation. The oscillatory stimulus consists of a slow (0.09 Hz) and a fast (0.38 Hz) half cycle. A large error was present in UVL patients when the slow half cycle was delivered toward the lesion side, but minimal toward the healthy side. This asymmetry diminished over time, but it remained abnormally large at 12 mo. In contrast, vestibulo-ocular reflex responses showed a large direction-dependent error only initially, then they normalized. Normalization also occurred for conventional reflex vestibular measures (caloric tests, subjective visual vertical, and head shaking nystagmus) and for perceptual function during symmetric rotation. Vestibular-related handicap, measured with the Dizziness Handicap Inventory (DHI) at 12 mo correlated with self-motion perception asymmetry but not with abnormalities in vestibulo-ocular function. We conclude that 1 ) a persistent self-motion perceptual bias is revealed by asymmetric rotation in UVLs despite vestibulo-ocular function becoming symmetric over time, 2 ) this dissociation is caused by differential perceptual-reflex adaptation to high- and low-frequency rotations when these are combined as with our asymmetric stimulus, 3 ) the findings imply differential central compensation for vestibuloperceptual and vestibulo-ocular reflex functions, and 4 ) self-motion perception disruption may mediate long-term vestibular-related handicap in UVL patients. NEW & NOTEWORTHY A novel vestibular stimulus, combining asymmetric slow and fast sinusoidal half cycles, revealed persistent vestibuloperceptual dysfunction in unilateral vestibular lesion (UVL) patients. The compensation of motion perception after UVL was slower than that of vestibulo-ocular reflex. Perceptual but not vestibulo-ocular reflex deficits correlated with dizziness-related handicap. Copyright © 2017 the American Physiological Society.

Functional ligand-gated purinergic receptors (P2X) in rat vestibular ganglion neurons.

PubMed

Ito, Ken; Chihara, Yasuhiro; Iwasaki, Shinichi; Komuta, Yukari; Sugasawa, Masashi; Sahara, Yoshinori

2010-08-01

The expression of purinergic receptors (P2X) on rat vestibular ganglion neurons (VGNs) was examined using whole-cell patch-clamp recordings. An application of adenosine 5'-triphosphate (ATP; 100microM) evoked inward currents in VGNs at a holding potential of -60mV. The decay time constant of the ATP-evoked currents was 2-4s, which is in between the values for rapidly desensitizing subgroups (P2X1 and P2X3) and slowly desensitizing subgroups (P2X2, P2X4, etc.), suggesting the heterogeneous expression of P2X receptors. A dose-response experiment showed an EC(50) of 11.0microM and a Hill's coefficient of 0.82. Suramin (100microM) reversibly inhibited the ATP-evoked inward currents. Alpha, beta-methylene ATP (100microM), a P2X-specific agonist, also evoked inward currents but less extensively than ATP. An application of adenosine 5'-dihosphate (ADP; 100microM) evoked similar, but much smaller, currents. The current-voltage relationship of the ATP-evoked conductance showed pronounced inward rectification with a reversal potential more positive than 0mV, suggesting non-selective cation conductance. However, the channel was not permeable to a large cation (N-methyl-d-glucamine) and acidification (pH 6.3) had little effect on the ATP-evoked conductance. RT-PCR confirmed the expression of five subtypes (P2X2-P2X6) in VGNs. The physiological role of P2X receptors includes the modulation of excitability at the synapses between hair cells and dendrites and/or trophic support (or also neuromodulation) from supporting cells surrounding the VGNs. Copyright 2010 Elsevier B.V. All rights reserved.

Zebrafish pax5 regulates development of the utricular macula and vestibular function.

PubMed

Kwak, Su-Jin; Vemaraju, Shruti; Moorman, Stephen J; Zeddies, David; Popper, Arthur N; Riley, Bruce B

2006-11-01

The zebrafish otic vesicle initially forms with only two sensory epithelia, the utricular and saccular maculae, which primarily mediate vestibular and auditory function, respectively. Here, we test the role of pax5, which is preferentially expressed in the utricular macula. Morpholino knockdown of pax5 disrupts vestibular function but not hearing. Neurons of the statoacoustic ganglion (SAG) develop normally. Utricular hair cells appear to form normally but a variable number subsequently undergo apoptosis and are extruded from the otic vesicle. Dendrites of the SAG persist in the utricle but become disorganized after hair cell loss. Hair cells in the saccule develop and survive normally. Otic expression of pax5 requires pax2a and fgf3, mutations in which cause vestibular defects, albeit by distinct mechanisms. Thus, pax5 works in conjunction with fgf3 and pax2a to establish and/or maintain the utricular macula and is essential for vestibular function. (c) 2006 Wiley-Liss, Inc.

Preoperative vestibular assessment protocol of cochlear implant surgery: an analytical descriptive study.

PubMed

Bittar, Roseli Saraiva Moreira; Sato, Eduardo Setsuo; Ribeiro, Douglas Jósimo Silva; Tsuji, Robinson Koji

Cochlear implants are undeniably an effective method for the recovery of hearing function in patients with hearing loss. To describe the preoperative vestibular assessment protocol in subjects who will be submitted to cochlear implants. Our institutional protocol provides the vestibular diagnosis through six simple tests: Romberg and Fukuda tests, assessment for spontaneous nystagmus, Head Impulse Test, evaluation for Head Shaking Nystagmus and caloric test. 21 patients were evaluated with a mean age of 42.75±14.38 years. Only 28% of the sample had all normal test results. The presence of asymmetric vestibular information was documented through the caloric test in 32% of the sample and spontaneous nystagmus was an important clue for the diagnosis. Bilateral vestibular areflexia was present in four subjects, unilateral arreflexia in three and bilateral hyporeflexia in two. The Head Impulse Test was a significant indicator for the diagnosis of areflexia in the tested ear (p=0.0001). The sensitized Romberg test using a foam pad was able to diagnose severe vestibular function impairment (p=0.003). The six clinical tests were able to identify the presence or absence of vestibular function and function asymmetry between the ears of the same individual. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Evaluation of vestibular functions in children with vertigo attacks

PubMed Central

Uneri, A; Turkdogan, D

2003-01-01

Aim: To examine vestibular system functions in children with episodic vertigo attacks. Methods: Thirty four children (20 males) aged 4–18 years with paroxysmal dizziness and/or vertigo attacks were evaluated. A medical history for vestibular symptoms and migraine was taken. Vestibular and auditory functions were assessed. Results: Chronic headache attacks consistent with migraine were reported in 12 children and motion sickness was reported in 30. Family history in first degree relatives was positive for migraine in 29 children and for episodic vertigo in 22. Electronystagmography and videonystagmography showed two types of nystagmus: spontaneous vestibular nystagmus (41%) and benign paroxysmal positional nystagmus (BPPN) (59%). The first type of nystagmus was assessed as a sign of vestibulopathy and the patients with BPPN were diagnosed as having benign paroxysmal positional vertigo (BPPV). Audiometric examination in four cases revealed bilateral sensory neural hearing loss in low frequencies. Pure tone averages in 30 cases were within normal ranges; however low frequencies in 28 of them were approximately 10 dB lower than high frequencies. Unilateral caloric responses diminished in eight children. Conclusions: Peripheral vestibular problems in childhood present in a wide spectrum, which varies from a short episode of dizziness to a typical vestibular attack with fluctuating sensory neural hearing loss or episodes of BPPV. A considerable number of these vestibular problems might be related to the migraine syndrome. PMID:12765917

Recovery from Spatial Neglect with Intra- and Transhemispheric Functional Connectivity Changes in Vestibular and Visual Cortex Areas-A Case Study.

PubMed

Conrad, Julian; Boegle, Rainer; Ertl, Matthias; Brandt, Thomas; Dieterich, Marianne

2018-01-01

Vestibular signals are involved in higher cortical functions like spatial orientation and its disorders. Vestibular dysfunction contributes, for example, to spatial neglect which can be transiently improved by caloric stimulation. The exact roles and mechanisms of the vestibular and visual systems for the recovery of neglect are not yet known. Resting-state functional connectivity (fc) magnetic resonance imaging was recorded in a patient with hemispatial neglect during the acute phase and after recovery 6 months later following a right middle cerebral artery infarction before and after caloric vestibular stimulation. Seeds in the vestibular [parietal operculum (OP2)], the parietal [posterior parietal cortex (PPC); 7A, hIP3], and the visual cortex (VC) were used for the analysis. During the acute stage after caloric stimulation the fc of the right OP2 to the left OP2, the anterior cingulum, and the para/hippocampus was increased bilaterally (i.e., the vestibular network), while the interhemispheric fc was reduced between homologous regions in the VC. After 6 months, similar fc increases in the vestibular network were found without stimulation. In addition, fc increases of the OP2 to the PPC and the VC were seen; interhemispherically this was true for both PPCs and for the right PPC to both VCs. Improvement of neglect after caloric stimulation in the acute phase was associated with increased fc of vestibular cortex areas in both hemispheres to the para-hippocampus and the dorsal anterior cingulum, but simultaneously with reduced interhemispheric VC connectivity. This disclosed a, to some extent, similar but also distinct short-term mechanism (vestibular stimulation) of an improvement of spatial orientation compared to the long-term recovery of neglect.

Altered auditory and vestibular functioning in individuals with low bone mineral density: a systematic review.

PubMed

Singh, Niraj Kumar; Jha, Raghav Hira; Gargeshwari, Aditi; Kumar, Prawin

2018-01-01

Alteration in the process of bone remodelling is associated with falls and fractures due to increased bone fragility and altered calcium functioning. The auditory system consists of skeletal structures and is, therefore, prone to getting affected by altered bone remodelling. In addition, the vestibule consists of huge volumes of calcium (CaCO3) in the form of otoconia crystals and alteration in functioning calcium levels could, therefore, result in vestibular symptoms. Thus, the present study aimed at compiling information from various studies on assessment of auditory or vestibular systems in individuals with reduced bone mineral density (BMD). A total of 1977 articles were searched using various databases and 19 full-length articles which reported auditory and vestibular outcomes in persons with low BMD were reviewed. An intricate relationship between altered BMD and audio-vestibular function was evident from the studies; nonetheless, how one aspect of hearing or balance affects the other is not clear. Significant effect of reduced bone mineral density could probably be due to the metabolic changes at the level of cochlea, secondary to alterations in BMD. One could also conclude that sympathetic remodelling is associated with vestibular problems in individual; however, whether vestibular problems lead to altered BMD cannot be ascertained with confidence. The studies reviewed in the article provide an evidence of possible involvement of hearing and vestibular system abnormalities in individuals with reduced bone mineral density. Hence, the assessment protocol for these individuals must include hearing and balance evaluation as mandatory for planning appropriate management.

Right-sided dominance of the bilateral vestibular system in the upper brainstem and thalamus.

PubMed

Dieterich, Marianne; Kirsch, V; Brandt, T

2017-10-01

MRI diffusion tensor imaging tractography was performed on the bilateral vestibular brainstem pathways, which run from the vestibular nuclei via the paramedian and posterolateral thalamic subnuclei to the parieto-insular vestibular cortex. Twenty-one right-handed healthy subjects participated. Quantitative analysis revealed a rope-ladder-like system of vestibular pathways in the brainstem with crossings at pontine and mesencephalic levels. Three structural types of right-left fiber distributions could be delineated: (1) evenly distributed pathways at the lower pontine level from the vestibular nuclei to the pontine crossing, (2) a moderate, pontomesencephalic right-sided lateralization between the pontine and mesencephalic crossings, and (3) a further increase of the right-sided lateralization above the mesencephalic crossing leading to the thalamic vestibular subnuclei. The increasing lateralization along the brainstem was the result of an asymmetric number of pontine and mesencephalic crossing fibers which was higher for left-to-right crossings. The dominance of the right vestibular meso-diencephalic circuitry in right-handers corresponds to the right-hemispheric dominance of the vestibular cortical network. The structural asymmetry apparent in the upper brainstem might be interpreted in relation to the different functions of the vestibular system depending on their anatomical level: a symmetrical sensorimotor reflex control of eye, head, and body mediated by the lower brainstem; a lateralized right-sided upper brainstem-thalamic function as part of the dominant right-sided cortical/subcortical vestibular system that enables a global percept of body motion and orientation in space.

Vestibular Restoration and Adaptation in Vestibular Neuritis and Ramsay Hunt Syndrome With Vertigo.

PubMed

Martin-Sanz, Eduardo; Rueda, Almudena; Esteban-Sanchez, Jonathan; Yanes, Joaquin; Rey-Martinez, Jorge; Sanz-Fernandez, Ricardo

2017-08-01

To evaluate vestibular restoration and the evolution of the compensatory saccades in acute severe inflammatory vestibular nerve paralysis, including vestibular neuritis and Ramsay Hunt syndrome with vertigo. Prospective. Tertiary referral center. Vestibular neuritis (n = 18) and Ramsay Hunt syndrome patients with vertigo (n = 13) were enrolled. After treatment with oral corticosteroids, patients were followed up for 6 months. Functional recovery of the facial nerve was scored according to the House-Brackman grading system. Caloric and video head impulse tests were performed in every patient at the time of enrolment. Subsequently, successive video head impulse test (vHIT) exploration was performed at the 1, 3, and 6-month follow-up. Eighteen patients with vestibular neuritis and 13 with Ramsay Hunt syndrome and associated vertigo were included. Vestibular function was significantly worse in patients with Ramsay Hunt syndrome than in those with vestibular neuritis. Similar compensatory saccades velocity and latency values were observed in both groups, in both the caloric and initial vHIT tests. Successive vHIT results showed a significantly higher vestibulo-ocular reflex gain recovery in vestibular neuritis patients than in Ramsay Hunt syndrome patients. A significantly faster reduction in the latency, velocity, and organization of the compensatory saccades was observed in neuritis than in Ramsay Hunt syndrome patients. In addition to the recovery of the vestibulo-ocular reflex, the reduction of latency, velocity and the organization of compensatory saccades play a role in vestibular compensation.

Vestibular vertigo is associated with abnormal sleep duration.

PubMed

Albathi, Monirah; Agrawal, Yuri

2017-01-01

Several small studies in animals and humans have suggested a relationship between vestibular function and sleep. In this study, we evaluate the association between vestibular vertigo and sleep duration in a large, representative sample of US adults. We used data from the National Health Interview Survey, which administered a Balance Supplement in 2008 in a sample of 20,950 adult respondents. We evaluated the cross-sectional association between vestibular vertigo (based on a well-validated definition) and sleep duration (defined as short <6 hours, normal 6-8 hours, and long >8 hours). We performed multiple and multinomial logistic regression analyses to estimate the odds ratio and relative risk ratio (RRR) of impaired sleep duration compared to normal sleep duration associated with vestibular vertigo. Analyses were adjusted for demographic, lifestyle and health behavior characteristics as well as relevant comorbid conditions. Thirty percent of individuals with vestibular vertigo reported abnormal sleep duration (15.5% short duration and 14.8% long duration). In adjusted analyses, individuals with vestibular vertigo had a 1.75 (95% CI 1.45-2.11) RRR of having short sleep duration compared to individuals without vestibular vertigo, and a 1.55 (95% CI 1.26-1.91) RRR of having long sleep duration compared to individuals without vestibular vertigo. This study presents epidemiologic evidence to support the association between vestibular function and sleep duration. Individuals with vestibular vertigo had a higher RRR for abnormally short or long sleep duration. Further work is needed to evaluate the causal direction(s) of this association.

Stochastic resonance in the synaptic transmission between hair cells and vestibular primary afferents in development.

PubMed

Flores, A; Manilla, S; Huidobro, N; De la Torre-Valdovinos, B; Kristeva, R; Mendez-Balbuena, I; Galindo, F; Treviño, M; Manjarrez, E

2016-05-13

The stochastic resonance (SR) is a phenomenon of nonlinear systems in which the addition of an intermediate level of noise improves the response of such system. Although SR has been studied in isolated hair cells and in the bullfrog sacculus, the occurrence of this phenomenon in the vestibular system in development is unknown. The purpose of the present study was to explore for the existence of SR via natural mechanical-stimulation in the hair cell-vestibular primary afferent transmission. In vitro experiments were performed on the posterior semicircular canal of the chicken inner ear during development. Our experiments showed that the signal-to-noise ratio of the afferent multiunit activity from E15 to P5 stages of development exhibited the SR phenomenon, which was characterized by an inverted U-like response as a function of the input noise level. The inverted U-like graphs of SR acquired their higher amplitude after the post-hatching stage of development. Blockage of the synaptic transmission with selective antagonists of the NMDA and AMPA/Kainate receptors abolished the SR of the afferent multiunit activity. Furthermore, computer simulations on a model of the hair cell - primary afferent synapse qualitatively reproduced this SR behavior and provided a possible explanation of how and where the SR could occur. These results demonstrate that a particular level of mechanical noise on the semicircular canals can improve the performance of the vestibular system in their peripheral sensory processing even during embryonic stages of development. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Disorders of balance and vestibular function in US adults: data from the National Health and Nutrition Examination Survey, 2001-2004.

PubMed

Agrawal, Yuri; Carey, John P; Della Santina, Charles C; Schubert, Michael C; Minor, Lloyd B

2009-05-25

Balance dysfunction can be debilitating and can lead to catastrophic outcomes such as falls. The inner ear vestibular system is an important contributor to balance control. However, to our knowledge, the prevalence of vestibular dysfunction in the United States and the magnitude of the increased risk of falling associated with vestibular dysfunction have never been estimated. The objective of this study was to determine the prevalence of vestibular dysfunction among US adults, evaluate differences by sociodemographic characteristics, and estimate the association between vestibular dysfunction and risk of falls. We included data from the 2001-2004 National Health and Nutrition Examination Surveys, which were cross-sectional surveys of US adults aged 40 years and older (n = 5086). The main outcome measure was vestibular function as measured by the modified Romberg Test of Standing Balance on Firm and Compliant Support Surfaces. From 2001 through 2004, 35.4% of US adults aged 40 years and older (69 million Americans) had vestibular dysfunction. Odds of vestibular dysfunction increased significantly with age, were 40.3% lower in individuals with more than a high school education, and were 70.0% higher among people with diabetes mellitus. Participants with vestibular dysfunction who were clinically symptomatic (ie, reported dizziness) had a 12-fold increase in the odds of falling. Vestibular dysfunction, as measured by a simple postural metric, is common among US adults. Vestibular dysfunction significantly increases the likelihood of falls, which are among the most morbid and costly health conditions affecting older individuals. These data suggest the importance of diagnosing, treating, and potentially screening for vestibular deficits to reduce the burden of fall-related injuries and deaths in the United States.

L-baclofen-sensitive GABAB binding sites in the medial vestibular nucleus localized by immunocytochemistry

NASA Technical Reports Server (NTRS)

Holstein, G. R.; Martinelli, G. P.; Cohen, B.

1992-01-01

L-Baclofen-sensitive GABAB binding sites in the medial vestibular nucleus (MVN) were identified immunocytochemically and visualized ultrastructurally in L-baclofen-preinjected rats and monkeys, using a mouse monoclonal antibody with specificity for the p-chlorophenyl moiety of baclofen. Saline-preinjected animals showed no immunostain. In drug-injected animals, there was evidence for both pre- and postsynaptic GABAergic inhibition in MVN mediated by GABAB receptors. These neural elements could be utilized in control of velocity storage in the vestibulo-ocular reflex.

Vestibular receptor cells and signal detection: bioaccelerometers and the hexagonal sampling of two-dimensional signals

NASA Technical Reports Server (NTRS)

Mugler, D. H.; Ross, M. D.

1990-01-01

The inner ear contains sensory organs which signal changes in head movement. The vestibular sacs, in particular, are sensitive to linear accelerations. Electron microscopic images have revealed the structure of tiny sensory hair bundles, whose mechanical deformation results in the initiation of neuronal activity and the transmission of electrical signals to the brain. The structure of the hair bundles is shown in this paper to be that of the most efficient two-dimensional phased-array signal processors.

Preserved vestibular evoked myogenic potentials (VEMP) in some patients with walking-induced oscillopsia due to bilateral vestibulopathy.

PubMed

Brantberg, Krister; Löfqvist, Lennart

2007-01-01

Bilateral vestibulopathy, i.e. decreased peripheral vestibular function affecting both ears, is characterized by unsteadiness of gait, particularly in darkness and by motion-induced oscillopsia. We have recently seen a few patients with severely impaired semicircular canal function albeit with rather normal vestibular evoked myogenic potentials (VEMP) suggesting normal saccular function. The five young patients, mean age 27 years (range 15-45), 4 males and 1 female, had severely impaired balance in darkness and they all reported walking-induced vertical oscillopsia. Hence, these patients with incomplete vestibular lesions had symptoms that were indistinguishable from the typical patient with bilateral vestibulopathy. Further, the findings in these patients suggest that saccular function probably contributes little to prevent walking-induced vertical oscillopsia.

Vestibular-visual interactions in flight simulators

NASA Technical Reports Server (NTRS)

Clark, B.

1977-01-01

All 139 research papers published under this ten-year program are listed. Experimental work was carried out at the Ames Research Center involving man's sensitivity to rotational acceleration, and psychophysical functioning of the semicircular canals; vestibular-visual interactions and effects of other sensory systems were studied in flight simulator environments. Experiments also dealt with the neurophysiological vestibular functions of animals, and flight management investigations of man-vehicle interactions.

The Effect of Vestibular Rehabilitation Therapy Program on Sensory Organization of Deaf Children With Bilateral Vestibular Dysfunction.

PubMed

Ebrahimi, Amir Abbas; Jamshidi, Ali Ashraf; Movallali, Guita; Rahgozar, Mehdi; Haghgoo, Hojjat Allah

2017-11-01

The purpose of this study was to determine the effect of vestibular rehabilitation therapy program on the sensory organization of deaf children with bilateral vestibular dysfunction. This cross-sectional and analytic study was conducted on 24 students between the age of 7 and 12 years (6 girls and 18 boys) with the profound sensorineural hearing loss (PTA>90 dB). They were assessed through the balance subtest in Bruininks-Oseretsky test of motor proficiency (BOTMP). For children which the total score of the balance subtest was 3 standard deviation lower than their peers with typical development, vestibular function testing was completed pre-intervention. Posturography Sensory organization testing (SOT) was completed pre- and post-intervention with SPS (Synapsys, Marseille, France). Children with bilateral vestibular impairment were randomly assigned to either the exercise or control group. Exercise intervention consisted of compensatory training, emphasizing enhancement of visual and somatosensory function, and balance training. The exercise group entered in vestibular rehabilitation therapy program for 8 weeks. The children initially participating in the control group were provided the exercise intervention following the post-test. Based on the results there was significant difference in condition 5 and 6, areas of limits of stability (LOS), vestibular ratio and global score in posturography at the end of the intervention, but there was no significant difference in the control group in posturography (P<0.05). The results indicated that testing of vestibular, and postural control function, as well as intervention for deficiencies identified, should be included in deaf children rehabilitation program.

Gravity receptor function in mice with graded otoconial deficiencies.

PubMed

Jones, Sherri M; Erway, Lawrence C; Johnson, Kenneth R; Yu, Heping; Jones, Timothy A

2004-05-01

The purpose of the present study was to examine gravity receptor function in mutant mouse strains with variable deficits in otoconia: lethal milk (lm), pallid (pa), tilted (tlt), mocha (mh), and muted (mu). Control animals were either age-matched heterozygotes or C57BL/6J (abbr. B6) mice. Gravity receptor function was measured using linear vestibular evoked potentials (VsEPs). Cage and swimming behaviors were also documented. Temporal bones were cleared to assess the overall otoconial deficit and to correlate structure and function for lm mice. Results confirmed the absence of VsEPs for mice that lacked otoconia completely. VsEP thresholds and amplitudes varied in mouse strains with variable loss of otoconia. Some heterozygotes also showed elevated VsEP thresholds in comparison to B6 mice. In lm mice, which have absent otoconia in the utricle and a variable loss of otoconia in the saccule, VsEPs were present and average P1/N1 amplitudes were highly correlated with the average loss of saccular otoconia (R = 0.77,p < 0.001). Cage and swimming behavior were not adversely affected in those animals with recordable VsEPs. Most, but not all, mice with absent VsEPs were unable to swim. Some animals were able to swim despite having no measurable gravity receptor response. The latter finding underscores the remarkable adaptive potential exhibited by neurobehavioral systems following profound sensory loss. It also shows that behavior alone may be an unreliable indicator of the extent of gravity receptor deficits.

Fluoxetine for vestibular dysfunction and anxiety: a prospective pilot study.

PubMed

Simon, Naomi M; Parker, Stephen W; Wernick-Robinson, Mara; Oppenheimer, Julia E; Hoge, Elizabeth A; Worthington, John J; Korbly, Nicole B; Pollack, Mark H

2005-01-01

Anxiety states and disorders amplify the symptoms and impairment associated with vestibular dysfunction. Five patients with inner ear vestibular dysfunction and anxiety were prospectively treated with fluoxetine, 20-60 mg/day, and received an extensive battery of assessments at baseline and after 12 weeks of treatment. Fluoxetine led to significant or near significant reductions in anxiety measures and in impairment due to dizziness; improvements in clinical balance function and vestibular function were less clear. The data add to the literature suggesting a role for selective serotonin reuptake inhibitors in the treatment of dizziness and anxiety.

Evaluation of Vestibular Functions in Patients with Vogt-Koyanagi-Harada Disease.

PubMed

Fujiwara, Keishi; Morita, Shinya; Hoshino, Kimiko; Fukuda, Atsushi; Nakamaru, Yuji; Homma, Akihiro

2017-01-01

Vogt-Koyanagi-Harada (VKH) disease is an idiopathic, multisystem autoimmune disorder characterized by bilateral, diffuse granulomatous uveitis associated with neurological, audiovestibular, and dermatological manifestations. The purpose of this study is to investigate vestibular functions in patients with VKH disease. A total of 43 patients with VKH disease in Hokkaido University Hospital were enrolled in this study. Subjective symptoms such as dizziness or vertigo and the results of various vestibular examinations including nystagmus testing, caloric testing, and vestibular-evoked myogenic potential (VEMP) testing were investigated. Eight of 42 patients (19.0%) complained of subjective vestibular symptoms. On the other hand, 12 of 28 patients (42.9%) showed nystagmus, and 7 of 15 patients (46.7%) showed unilateral or bilateral weakness in the caloric test. VEMP testing was performed for 16 patients. Seven (43.8%) and 8 (50.0%) patients were evaluated as abnormal in cervical VEMP and ocular VEMP testing, respectively. The rate of detection of nystagmus was significantly higher than that of subjective symptoms. As vestibular dysfunction in patients with VKH disease cannot be detected through history taking alone, nystagmus testing, caloric testing, and VEMP testing should be performed to evaluate vestibular functions associated with VKH disease. It is considered that abnormal VEMP findings are associated with otolith organ dysfunction. © 2017 S. Karger AG, Basel.

The video ocular counter-roll (vOCR): a clinical test to detect loss of otolith-ocular function

PubMed Central

Otero-Millan, Jorge; Treviño, Carolina; Winnick, Ariel; Zee, David S.; Carey, John P.; Kheradmand, Amir

2017-01-01

Conclusion vOCR can detect loss of otolith-ocular function without specifying the side of vestibular loss. Since vOCR is measured with a simple head tilt maneuver, it can be potentially used as a bedside clinical test in combination with video head impulse test. Objective Video-oculography (VOG) goggles are being integrated into the bedside assessment of patients with vestibular disorders. Lacking, however, is a method to evaluate otolith function. This study validated a VOG test for loss of otolith function. Methods VOG was used to measure ocular counter-roll (vOCR) in 12 healthy controls, 14 patients with unilateral vestibular loss (UVL), and six patients with bilateral vestibular loss (BVL) with a static lateral head tilt of 30°. The results were compared with vestibular evoked myogenic potentials (VEMP), a widely-used laboratory test of otolith function. Results The average vOCR for healthy controls (4.6°) was significantly different from UVL (2.7°) and BVL (1.6°) patients (p < 0.0001). The vOCR and VEMP measurements were correlated across subjects, especially the click and tap oVEMPs (click oVEMP R = 0.45, tap oVEMP R = 0.51; p < 0.0003). The receiver operator characteristic (ROC) analysis showed that vOCR and VEMPs detected loss of otolith function equally well. The best threshold for vOCR to detect vestibular loss was at 3°. The vOCR values from the side of vestibular loss and the healthy side were not different in UVL patients (2.53° vs 2.8°; p = 0.59). PMID:28084887

Nicergoline in the treatment of dizziness in elderly patients. A review.

PubMed

Felisati, G; Pignataro, O; Di Girolamo, A; Bruno, E; Alessandrini, M; Guidetti, G; Monzani, D; Beldi, A M; Mira, E; Benazzo, M; Pallestrini, E; Caligo, G; Casani, A; Battaglia, A

2004-01-01

In elderly patients, dizziness occurs very frequently with significant effects on the patient's life. Its frequency increases with age, and may arise from a variety of causes. Chronic dysequilibrium in elderly patients is most probably related to disturbances within the central nervous system, due either to altered neuronal functions or to an underlying vascular disease. Nicergoline, a drug used in the treatment of cognitive disturbances in geriatric patients, improves dizziness in elderly demented and non-demented patients. In a double blind,placebo controlled trial the drug improved (i) the severity of symptoms, measured by the dizziness assessment rating scale (DARS), (ii) the overall clinical conditions revealed by global impression scale, and (iii) the perceived quality of life estimated by the dizziness handicap inventory (DHI). These results indicate a possible positive effect also on posturographic measures. Moreover, the improvement occurred at no expense of the established strategy of postural control suggesting that the effect is mediated by a substitute compensatory mechanism allowing the patient to preserve consolidated postural strategies. The results of previous open clinical studies in about 3000 patients are in agreement with those findings. Overall, severity of symptoms decreased by 68 % (57 % in the control study). Globally, the results indicate a beneficial effect of nicergoline on symptoms related to balance disorders of central origin. Animal studies show that the drug displays a broad spectrum of actions on cellular and molecular mechanisms. Moreover, animal research specifically aimed at vestibular pathophysiology has revealed that nicergoline improves vestibular compensation in models of vestibular lesion. Chronic treatment with nicergoline improved the time-course of behavioral recovery in old rats after hemi-labyrinthectomy and counteracted the regulation of cholinergic receptors observed after lesion in old rats. Nicergoline interacts at several levels by various mechanisms, from the molecular level to cognitive function, probably enhancing spontaneous plasticity phenomena underlying the central vestibular compensation. This effect is not dependent from the interaction with a single-transmitter-identified neural pathway, but from anatomical, functional and neurochemical synergistic adjustments in several brain areas.

Investigations of the Effects of Altered Vestibular System Function on Hindlimb Anti-Gravity Muscles

NASA Technical Reports Server (NTRS)

Lowery, Mary Sue

1998-01-01

Exposure to different gravitational environments, both the microgravity of spaceflight and the hypergravity of centrifugation, result in altered vestibulo-spinal function which can be reversed by reacclimation to earth gravity (2). Control of orientation, posture, and locomotion are functions of the vestibular system which are altered by changes in gravitational environment. Not only is the vestibular system involved with coordination and proprioception, but the gravity sensing portion of the vestibular system also plays a major role in maintaining muscle tone through projections to spinal cord motoneurons that control anti-gravity muscles. I have been involved with investigations of several aspects of the link between vestibular inputs and muscle morphology and function during my work with Dr. Nancy Daunton this summer and the previous summer. We have prepared a manuscript for submission (4) to Aviation, Space, and Environmental Medicine based on work that I performed last summer in Dr. Daunton's lab. Techniques developed for that project will be utilized in subsequent experiments begun in the summer of 1998. I have been involved with the development of a pilot project to test the effects of vestibular galvanic stimulation (VGS) on anti-gravity muscles and in another project testing the effects of the ototoxic drug streptomycin on the otolith-spinal reflex and anti-gravity muscle morphology.

Direct muscarinic and nicotinic receptor-mediated excitation of rat medial vestibular nucleus neurons in vitro

NASA Technical Reports Server (NTRS)

Phelan, K. D.; Gallagher, J. P.

1992-01-01

We have utilized intracellular recording techniques to investigate the cholinoceptivity of rat medial vestibular nucleus (MVN) neurons in a submerged brain slice preparation. Exogenous application of the mixed cholinergic agonists, acetylcholine (ACh) or carbachol (CCh), produced predominantly membrane depolarization, induction of action potential firing, and decreased input resistance. Application of the selective muscarinic receptor agonist muscarine (MUSC), or the selective nicotinic receptor agonists nicotine (NIC) or 1,1-dimethyl-4-phenylpiperazinium (DMPP) also produced membrane depolarizations. The MUSC-induced depolarization was accompanied by decreased conductance, while an increase in conductance appeared to underlie the NIC- and DMPP-induced depolarizations. The muscarinic and nicotinic receptor mediated depolarizations persisted in tetrodotoxin and/or low Ca2+/high Mg2+ containing media, suggesting direct postsynaptic receptor activation. The MUSC-induced depolarization could be reversibly blocked by the selective muscarinic-receptor antagonist, atropine, while the DMPP-induced depolarization could be reversibly suppressed by the selective ganglionic nicotinic-receptor antagonist, mecamylamine. Some neurons exhibited a transient membrane hyperpolarization during the depolarizing response to CCh or MUSC application. This transient inhibition could be reversibly blocked by the gamma-aminobutyric acid (GABA) antagonist, bicuculline, suggesting that the underlying hyperpolarization results indirectly from the endogenous release of GABA acting at GABA receptors. This study confirms the cholinoceptivity of MVN neurons and establishes that individual MVN cells possess muscarinic as well as nicotinic receptors. The data provide support for a prominent role of cholinergic mechanisms in the direct and indirect regulation of the excitability of MVN neurons.

Brain Activations for Vestibular Stimulation and Dual Tasking Change with Spaceflight

NASA Technical Reports Server (NTRS)

Yuan, Peng; Koppelmans, Vincent; Reuter-Lorenz, Patricia; De Dios, Yiri; Gadd, Nichole; Wood, Scott; Riascos, Roy; Kofman, Igor; Bloomberg, Jacob; Mulavara, Ajitkumar;

Vestibulo-Sympathetic Responses

PubMed Central

Yates, Bill J; Bolton, Philip S.; Macefield, Vaughan G.

2014-01-01

Evidence accumulated over 30 years, from experiments on animals and human subjects, has conclusively demonstrated that inputs from the vestibular otolith organs contribute to the control of blood pressure during movement and changes in posture. This review considers the effects of gravity on the body axis, and the consequences of postural changes on blood distribution in the body. It then separately considers findings collected in experiments on animals and human subjects demonstrating that the vestibular system regulates blood distribution in the body during movement. Vestibulosympathetic reflexes differ from responses triggered by unloading of cardiovascular receptors such as baroreceptors and cardiopulmonary receptors, as they can be elicited before a change in blood distribution occurs in the body. Dissimilarities in the expression of vestibulosympathetic reflexes in humans and animals are also described. In particular, there is evidence from experiments in animals, but not humans, that vestibulosympathetic reflexes are patterned, and differ between body regions. Results from neurophysiological and neuroanatomical studies in animals are discussed that identify the neurons that mediate vestibulosympathetic responses, which include cells in the caudal aspect of the vestibular nucleus complex, interneurons in the lateral medullary reticular formation, and bulbospinal neurons in the rostral ventrolateral medulla (RVLM). Recent findings showing that cognition can modify the gain of vestibulosympathetic responses are also presented, and neural pathways that could mediate adaptive plasticity in the responses are proposed, including connections of the posterior cerebellar vermis with the vestibular nuclei and brainstem nuclei that regulate blood pressure. PMID:24715571

Influence of testosterone on synaptic transmission in the rat medial vestibular nuclei: estrogenic and androgenic effects.

PubMed

Grassi, S; Frondaroli, A; Di Mauro, M; Pettorossi, V E

2010-12-15

In brainstem slices of young male rat, we investigated the influence of the neuroactive steroid testosterone (T) on the synaptic responses by analyzing the field potential evoked in the medial vestibular nucleus (MVN) by vestibular afferent stimulation. T induced three distinct and independent long-term synaptic changes: fast long-lasting potentiation (fLP), slow long-lasting potentiation (sLP) and long-lasting depression (LD). The fLP was mediated by 17β-estradiol (E(2)) since it was abolished by blocking the estrogen receptors (ERs) or the enzyme converting T to E(2). Conversely, sLP and LD were mediated by 5α-dihydrotestosterone (DHT) since they were prevented by blocking the androgen receptors (ARs) or the enzyme converting T to DHT. Therefore, the synaptic effects of T were mediated by its androgenic or estrogenic metabolites. The pathways leading to estrogenic and androgenic conversion of T might be co-localized since, the occurrence of fLP under block of androgenic pathway, and that of sLP and LD under estrogenic block, were higher than those observed without blocks. In case of co-localization, the effect on synaptic transmission should depend on the prevailing enzymatic activity. We conclude that circulating and neuronal T can remarkably influence synaptic responses of the vestibular neurons in different and opposite ways, depending on its conversion to estrogenic or androgenic metabolites. Copyright © 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

Developmental shift from long-term depression to long-term potentiation in the rat medial vestibular nuclei: role of group I metabotropic glutamate receptors

PubMed Central

Puyal, Julien; Grassi, Silvarosa; Dieni, Cristina; Frondaroli, Adele; Demêmes, Danielle; Raymond, Jaqueline; Pettorossi, Vito Enrico

2003-01-01

The effects of high frequency stimulation (HFS) of the primary vestibular afferents on synaptic transmission in the ventral part of the medial vestibular nuclei (vMVN) were studied during postnatal development and compared with the changes in the expression of the group I metabotropic glutamate receptor (mGluR) subtypes, mGluR1 and mGluR5. During the first stages of development, HFS always induced a mGluR5- and GABAA-dependent long-term depression (LTD) which did not require NMDA receptor and mGluR1 activation. The probability of inducing LTD decreased progressively throughout the development and it was zero at about the end of the second postnatal week. Conversely, long-term potentiation (LTP) appeared at the beginning of the second week and its occurrence increased to reach the adult value at the end of the third week. Of interest, the sudden change in the LTP frequency occurred at the time of eye opening, about the end of the second postnatal week. LTP depended on NMDA receptor and mGluR1 activation. In parallel with the modifications in synaptic plasticity, we observed that the expression patterns and localizations of mGluR5 and mGluR1 in the medial vestibular nuclei (MVN) changed during postnatal development. At the earlier stages the mGluR1 expression was minimal, then increased progressively. In contrast, mGluR5 expression was initially high, then decreased. While mGluR1 was exclusively localized in neuronal compartments and concentrated at the postsynaptic sites at all stages observed, mGluR5 was found mainly in neuronal compartments at immature stages, then preferentially in glial compartments at mature stages. These results provide the first evidence for a progressive change from LTD to LTP accompanied by a distinct maturation expression of mGluR1 and mGluR5 during the development of the MVN. PMID:12972627

Sensory Processing in Rhesus Monkeys: Developmental Continuity, Prenatal Treatment, and Genetic Influences

PubMed Central

Schneider, Mary L.; Moore, Colleen F.; Adkins, Miriam; Barr, Christina S.; Larson, Julie A.; Resch, Leslie M.; Roberts, Andrew

2017-01-01

Neonatal sensory processing (tactile and vestibular function) was tested in 78 rhesus macaques from two experiments. At ages 4–5 years, striatal dopamine D2 receptor binding was examined using positron emission tomography. At ages 5–7 years, adult sensory processing was assessed. Findings were: (a) prenatal stress exposure yielded less optimal neonatal sensory processing; (b) animals carrying the short rh5-HTTLPR allele had less optimal neonatal sensory scores than monkeys homozygous for the long allele; (c) neonatal sensory processing was significantly related to striatal D2 receptor binding for carriers of the short allele, but not for animals homozygous for the long allele; and (d) there was moderate developmental continuity in sensory processing from the neonatal period to adulthood. PMID:27338151

The OTOLITH Experiment - Assessment of Otolith Function During Postflight Re-adaption

NASA Technical Reports Server (NTRS)

Clarke, A. H.; Wood, S. J.; Schoenfeld, U.

2010-01-01

The ongoing "Otolith" experiment is designed to comprehensively assess the otolith function during the re-adaptation phase after spaceflight. The novel protocol includes unilateral testing of each of the two otolith organs the utricle and the saccule. To assess utricle function, the otolith-ocular response (OOR) and the subjective visual vertical (SVV) are measured during unilateral centrifugation, which permits independent stimulation of the right and left ear. Measurement of the unilateral otolith-ocular response (uOOR) yields information on the response behaviour of the right and left peripheral utricles, whereas the SVV reflects the behaviour of the entire pathway from the peripheral otolith receptors to the vestibular cortex. Thus, by comparative evaluation of the results from the two tests, the degree of peripheral versus central adaptation during the post-flight period can be determined. To assess unilateral saccule function, vestibular evoked myogenic potentials (VEMP) are recorded. Since the saccules are predominantly aligned to gravity, and interplay with the antigravity muscles, it is hypothesised that these potentials shall be altered after spaceflight. To date the study has been conducted with 5 of a planned 8 short-flight Shuttle astronauts. Preliminary results will be discussed together with those from clinical studies of dizziness patients, where the same test protocol is employed. ACKNOWLEDGEMENT This work is supported by the German Aerospace Center (Grant DLR W130729) and is conducted under the auspices of ESA, in cooperation with NASA.

Vestibular Rehabilitation for Peripheral Vestibular Hypofunction: An Evidence-Based Clinical Practice Guideline

PubMed Central

Herdman, Susan J.; Whitney, Susan L.; Cass, Stephen P.; Clendaniel, Richard A.; Fife, Terry D.; Furman, Joseph M.; Getchius, Thomas S. D.; Goebel, Joel A.; Shepard, Neil T.; Woodhouse, Sheelah N.

2016-01-01

Background: Uncompensated vestibular hypofunction results in postural instability, visual blurring with head movement, and subjective complaints of dizziness and/or imbalance. We sought to answer the question, “Is vestibular exercise effective at enhancing recovery of function in people with peripheral (unilateral or bilateral) vestibular hypofunction?” Methods: A systematic review of the literature was performed in 5 databases published after 1985 and 5 additional sources for relevant publications were searched. Article types included meta-analyses, systematic reviews, randomized controlled trials, cohort studies, case control series, and case series for human subjects, published in English. One hundred thirty-five articles were identified as relevant to this clinical practice guideline. Results/Discussion: Based on strong evidence and a preponderance of benefit over harm, clinicians should offer vestibular rehabilitation to persons with unilateral and bilateral vestibular hypofunction with impairments and functional limitations related to the vestibular deficit. Based on strong evidence and a preponderance of harm over benefit, clinicians should not include voluntary saccadic or smooth-pursuit eye movements in isolation (ie, without head movement) as specific exercises for gaze stability. Based on moderate evidence, clinicians may offer specific exercise techniques to target identified impairments or functional limitations. Based on moderate evidence and in consideration of patient preference, clinicians may provide supervised vestibular rehabilitation. Based on expert opinion extrapolated from the evidence, clinicians may prescribe a minimum of 3 times per day for the performance of gaze stability exercises as 1 component of a home exercise program. Based on expert opinion extrapolated from the evidence (range of supervised visits: 2-38 weeks, mean = 10 weeks), clinicians may consider providing adequate supervised vestibular rehabilitation sessions for the patient to understand the goals of the program and how to manage and progress themselves independently. As a general guide, persons without significant comorbidities that affect mobility and with acute or subacute unilateral vestibular hypofunction may need once a week supervised sessions for 2 to 3 weeks; persons with chronic unilateral vestibular hypofunction may need once a week sessions for 4 to 6 weeks; and persons with bilateral vestibular hypofunction may need once a week sessions for 8 to 12 weeks. In addition to supervised sessions, patients are provided a daily home exercise program. Disclaimer: These recommendations are intended as a guide for physical therapists and clinicians to optimize rehabilitation outcomes for persons with peripheral vestibular hypofunction undergoing vestibular rehabilitation. Video Abstract available for more insights from the author (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A124). PMID:26913496

A new saccadic indicator of peripheral vestibular function based on the video head impulse test

PubMed Central

MacDougall, Hamish G.; McGarvie, Leigh A.; Rogers, Stephen J.; Manzari, Leonardo; Burgess, Ann M.; Curthoys, Ian S.; Weber, Konrad P.

2016-01-01

Objective: While compensatory saccades indicate vestibular loss in the conventional head impulse test paradigm (HIMP), in which the participant fixates an earth-fixed target, we investigated a complementary suppression head impulse paradigm (SHIMP), in which the participant is fixating a head-fixed target to elicit anticompensatory saccades as a sign of vestibular function. Methods: HIMP and SHIMP eye movement responses were measured with the horizontal video head impulse test in patients with unilateral vestibular loss, patients with bilateral vestibular loss, and in healthy controls. Results: Vestibulo-ocular reflex gains showed close correlation (R2 = 0.97) with slightly lower SHIMP than HIMP gains (mean gain difference 0.06 ± 0.05 SD, p < 0.001). However, the 2 paradigms produced complementary catch-up saccade patterns: HIMP elicited compensatory saccades in patients but rarely in controls, whereas SHIMP elicited large anticompensatory saccades in controls, but smaller or no saccades in bilateral vestibular loss. Unilateral vestibular loss produced covert saccades in HIMP, but later and smaller saccades in SHIMP toward the affected side. Cumulative HIMP and SHIMP saccade amplitude differentiated patients from controls with high sensitivity and specificity. Conclusions: While compensatory saccades indicate vestibular loss in conventional HIMP, anticompensatory saccades in SHIMP using a head-fixed target indicate vestibular function. SHIMP saccades usually appear later than HIMP saccades, therefore being more salient to the naked eye and facilitating vestibulo-ocular reflex gain measurements. The new paradigm is intuitive and easy to explain to patients, and the SHIMP results complement those from the standard video head impulse test. Classification of evidence: This case-control study provides Class III evidence that SHIMP accurately identifies patients with unilateral or bilateral vestibulopathies. PMID:27251884

Retinoic acid deficiency impairs the vestibular function.

PubMed

Romand, Raymond; Krezel, Wojciech; Beraneck, Mathieu; Cammas, Laura; Fraulob, Valérie; Messaddeq, Nadia; Kessler, Pascal; Hashino, Eri; Dollé, Pascal

2013-03-27

The retinaldehyde dehydrogenase 3 (Raldh3) gene encodes a major retinoic acid synthesizing enzyme and is highly expressed in the inner ear during embryogenesis. We found that mice deficient in Raldh3 bear severe impairment in vestibular functions. These mutant mice exhibited spontaneous circling/tilted behaviors and performed poorly in several vestibular-motor function tests. In addition, video-oculography revealed a complete loss of the maculo-ocular reflex and a significant reduction in the horizontal angular vestibulo-ocular reflex, indicating that detection of both linear acceleration and angular rotation were compromised in the mutants. Consistent with these behavioral and functional deficiencies, morphological anomalies, characterized by a smaller vestibular organ with thinner semicircular canals and a significant reduction in the number of otoconia in the saccule and the utricle, were consistently observed in the Raldh3 mutants. The loss of otoconia in the mutants may be attributed, at least in part, to significantly reduced expression of Otop1, which encodes a protein known to be involved in calcium regulation in the otolithic organs. Our data thus reveal a previously unrecognized role of Raldh3 in structural and functional development of the vestibular end organs.

Manual control of yaw motion with combined visual and vestibular cues

NASA Technical Reports Server (NTRS)

Zacharias, G. L.; Young, L. R.

1977-01-01

Measurements are made of manual control performance in the closed-loop task of nulling perceived self-rotation velocity about an earth-vertical axis. Self-velocity estimation was modelled as a function of the simultaneous presentation of vestibular and peripheral visual field motion cues. Based on measured low-frequency operator behavior in three visual field environments, a parallel channel linear model is proposed which has separate visual and vestibular pathways summing in a complementary manner. A correction to the frequency responses is provided by a separate measurement of manual control performance in an analogous visual pursuit nulling task. The resulting dual-input describing function for motion perception dependence on combined cue presentation supports the complementary model, in which vestibular cues dominate sensation at frequencies above 0.05 Hz. The describing function model is extended by the proposal of a non-linear cue conflict model, in which cue weighting depends on the level of agreement between visual and vestibular cues.

Equilibrium and Orientation in Cephalopods.

ERIC Educational Resources Information Center

Budelmann, Bernd-Ulrich

1980-01-01

Describes the structure of the equilibrium receptor system in cephalopods, comparing it to the vertebrate counterpart--the vestibular system. Relates the evolution of this complex system to the competition of cephalopods with fishes. (CS)

Patients with chronic dizziness following traumatic head injury typically have multiple diagnoses involving combined peripheral and central vestibular dysfunction.

PubMed

Arshad, Q; Roberts, R E; Ahmad, H; Lobo, R; Patel, M; Ham, T; Sharp, D J; Seemungal, B M

2017-04-01

We hypothesised that chronic vestibular symptoms (CVS) of imbalance and dizziness post-traumatic head injury (THI) may relate to: (i) the occurrence of multiple simultaneous vestibular diagnoses including both peripheral and central vestibular dysfunction in individual patients increasing the chance of missed diagnoses and suboptimal treatment; (ii) an impaired response to vestibular rehabilitation since the central mechanisms that mediate rehabilitation related brain plasticity may themselves be disrupted. We report the results of a retrospective analysis of both the comprehensive clinical and vestibular laboratory testing of 20 consecutive THI patients with prominent and persisting vestibular symptoms still present at least 6months post THI. Individual THI patients typically had multiple vestibular diagnoses and unique to this group of vestibular patients, often displayed both peripheral and central vestibular dysfunction. Despite expert neuro-otological management, at two years 20% of patients still had persisting vestibular symptoms. In summary, chronic vestibular dysfunction in THI could relate to: (i) the presence of multiple vestibular diagnoses, increasing the risk of 'missed' vestibular diagnoses leading to persisting symptoms; (ii) the impact of brain trauma which may impair brain plasticity mediated repair mechanisms. Apart from alerting physicians to the potential for multiple vestibular diagnoses in THI, future work to identify the specific deficits in brain function mediating poor recovery from post-THI vestibular dysfunction could provide the rationale for developing new therapy for head injury patients whose vestibular symptoms are resistant to treatment. Copyright © 2017. Published by Elsevier B.V.

Vestibular-visual interactions in flight simulators

NASA Technical Reports Server (NTRS)

Clark, B.

1977-01-01

The following research work is reported: (1) vestibular-visual interactions; (2) flight management and crew system interactions; (3) peripheral cue utilization in simulation technology; (4) control of signs and symptoms of motion sickness; (5) auditory cue utilization in flight simulators, and (6) vestibular function: Animal experiments.

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

NASA Technical Reports Server (NTRS)

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

1995-01-01

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.

Failure on the Foam Eyes Closed Test of Standing Balance Associated With Reduced Semicircular Canal Function in Healthy Older Adults.

PubMed

Anson, Eric; Bigelow, Robin T; Studenski, Stephanie; Deshpande, Nandini; Agrawal, Yuri

2018-06-11

Standing on foam with eyes closed (FOEC) has been characterized as a measure of vestibular function; however, the relative contribution of vestibular function and proprioceptive function to the FOEC test has not been well described. In this study, the authors investigate the relationship between peripheral sensory systems (vestibular and proprioception) and performance on the FOEC test in a cohort of healthy adults. A total of 563 community-dwelling healthy adults (mean age, 72.7 [SD, 12.6] years; range, 27 to 93 years) participating in the Baltimore Longitudinal Study of Aging were tested. Proprioceptive threshold (PROP) was evaluated with passive motion detection at the right ankle. Vestibulo-ocular reflex (VOR) gain was measured using video head impulses. Otolith function was measured with cervical and ocular vestibular-evoked myogenic potentials. Participants stood on FOEC for 40 sec while wearing BalanSens (BioSensics, LLC, Watertown, MA) to quantify center of mass sway area. A mixed-model multiple logistic regression was used to examine the odds of passing the FOEC test based on PROP, VOR, cervical vestibular-evoked myogenic potential, and ocular vestibular-evoked myogenic potential function in a multisensory model while controlling for age and gender. The odds of passing the FOEC test decreased by 15% (p < 0.001) for each year of increasing age and by 8% with every 0.1 reduction in VOR gain (p = 0.025). Neither PROP nor otolith function was significantly associated with passing the FOEC test. Failure to maintain balance during FOEC may serve as a proxy for rotational vestibular contributions to postural control. Semicircular canals are more sensitive to low-frequency motion than otoliths that may explain these relationships because standing sway is dominated by lower frequencies. Lower VOR gain and increased age independently decreased the odds of passing the test.

Tonic Investigation Concept of Cervico-vestibular Muscle Afferents

PubMed Central

Dorn, Linda Josephine; Lappat, Annabelle; Neuhuber, Winfried; Scherer, Hans; Olze, Heidi; Hölzl, Matthias

2016-01-01

Introduction Interdisciplinary research has contributed greatly to an improved understanding of the vestibular system. To date, however, very little research has focused on the vestibular system's somatosensory afferents. To ensure the diagnostic quality of vestibular somatosensory afferent data, especially the extra cranial afferents, stimulation of the vestibular balance system has to be precluded. Objective Sophisticated movements require intra- and extra cranial vestibular receptors. The study's objective is to evaluate an investigation concept for cervico-vestibular afferents with respect to clinical feasibility. Methods A dedicated chair was constructed, permitting three-dimensional trunk excursions, during which the volunteer's head remains fixed. Whether or not a cervicotonic provocation nystagmus (c-PN) can be induced with static trunk excursion is to be evaluated and if this can be influenced by cervical monophasic transcutaneous electrical nerve stimulation (c-TENS) with a randomized test group. 3D-video-oculography (VOG) was used to record any change in cervico-ocular examination parameters. The occurring nystagmuses were evaluated visually due to the small caliber of nystagmus amplitudes in healthy volunteers. Results The results demonstrate: no influence of placebo-controlled c-TENS on the spontaneous nystagmus; a significant increase of the vertical nystagmus on the 3D-trunk-excursion chair in static trunk flexion with cervical provocation in all young healthy volunteers (n = 49); and a significant difference between vertical and horizontal nystagmuses during static trunk excursion after placebo-controlled c-TENS, except for the horizontal nystagmus during trunk torsion. Conclusion We hope this cervicotonic investigation concept on the 3D trunk-excursion chair will contribute to new diagnostic and therapeutic perspectives on cervical pathologies in vestibular head-to-trunk alignment. PMID:28050208

Subclinical vestibular dysfunction in migraine patients: a preliminary study of ocular and rectified cervical vestibular evoked myogenic potentials.

PubMed

Kim, Chul-Ho; Jang, Min-Uk; Choi, Hui-Chul; Sohn, Jong-Hee

2015-01-01

Many studies have identified various vestibular symptoms and laboratory abnormalities in migraineurs. Although the vestibular tests may be abnormal, the changes may exist without vestibular symptoms. To date, vestibular-evoked myogenic potential (VEMP) has been the easiest and simplest test for measuring vestibular function in clinical practice. Cervical VEMP (cVEMP) represents a vestibulo-collic reflex, whereas ocular VEMP (oVEMP) reflects a vestibulo-ocular pathway. Therefore, we determined whether ocular and rectified cervical VEMPs differed in patients with migraine or tension type headache (TTH) and compared the results to controls with no accompanying vestibular symptoms. The present study included 38 females with migraine without aura, 30 with episodic TTH, and 50 healthy controls without vestibular symptoms. oVEMP and cVEMP using a blood pressure manometer were recorded during a headache-free period. From the VEMP graphs, latency and amplitude parameters were analyzed, especially following EMG rectification in cVEMP. With respect to oVEMP, the migraine group exhibited significantly longer mean latencies of bilateral n1 and left p1 than the other groups (p < 0.05). Amplitudes of n1-p1 were lower than in other groups, but the difference did not reach statistical significance. In regards to cVEMP, p13 and n23 latencies and amplitudes after rectification did not differ significantly among groups. An abnormal interictal oVEMP profile was associated with subclinical vestibular dysfunction in migraineurs, suggesting pathology within the vestibulo-ocular reflex. oVEMP is a more reliable measure than cVEMP to evaluate vestibular function in migraineurs, although results from the two tests in patients with migraine are complementary.

The vestibulocochlear nerve (VIII).

PubMed

Benoudiba, F; Toulgoat, F; Sarrazin, J-L

2013-10-01

The vestibulocochlear nerve (8th cranial nerve) is a sensory nerve. It is made up of two nerves, the cochlear, which transmits sound and the vestibular which controls balance. It is an intracranial nerve which runs from the sensory receptors in the internal ear to the brain stem nuclei and finally to the auditory areas: the post-central gyrus and superior temporal auditory cortex. The most common lesions responsible for damage to VIII are vestibular Schwannomas. This report reviews the anatomy and various investigations of the nerve. Copyright © 2013. Published by Elsevier Masson SAS.

Short latency vestibular evoked potentials in the chicken embryo

NASA Technical Reports Server (NTRS)

Jones, S. M.; Jones, T. A.

1996-01-01

Electrophysiological responses to pulsed linear acceleration stimuli were recorded in chicken embryos incubated for 19 or 20 days (E19/E20). Responses occurred within the first 16 ms following the stimulus onset. The evoked potentials disappeared following bilateral labyrinthectomy, but persisted following cochlear destruction alone, thus demonstrating that the responses were vestibular. Approximately 8 to 10 response peaks could be identified. The first 4 positive and corresponding negative components (early peaks with latencies < 6.0 ms) were scored and latencies and amplitudes quantified. Vestibular response latencies were significantly longer (P < 0.01) and amplitudes significantly smaller (P < 0.001) than those observed in 2-week-old birds. Mean response threshold for anesthetized embryos was -15.9dBre 1.0 g/ms, which was significantly higher (P < 0.03) than those observed in 2-week-old birds (-23.0dBre 1.0 g/ms). Latency/intensity functions (that is, slopes) were not significantly different between embryos and 2-week-old animals, but amplitude/intensity functions for embryos were significantly shallower than those for 2-week-old birds (P < 0.001). We presume that these differences reflect the refinement of sensory function that occurs following 19 to 20 days of incubation. The recording of vestibular evoked potentials provides an objective, direct and noninvasive measure of peripheral vestibular function in the embryo and, as such, the method shows promise as an investigative tool. The results of the present study form the definitive basis for using vestibular evoked potentials in the detailed study of avian vestibular ontogeny and factors that may influence it.

The function and molecular identity of inward rectifier channels in vestibular hair cells of the mouse inner ear

PubMed Central

Levin, Michaela E.

2012-01-01

Inner ear hair cells respond to mechanical stimuli with graded receptor potentials. These graded responses are modulated by a host of voltage-dependent currents that flow across the basolateral membrane. Here, we examine the molecular identity and the function of a class of voltage-dependent ion channels that carries the potassium-selective inward rectifier current known as IK1. IK1 has been identified in vestibular hair cells of various species, but its molecular composition and functional contributions remain obscure. We used quantitative RT-PCR to show that the inward rectifier gene, Kir2.1, is highly expressed in mouse utricle between embryonic day 15 and adulthood. We confirmed Kir2.1 protein expression in hair cells by immunolocalization. To examine the molecular composition of IK1, we recorded voltage-dependent currents from type II hair cells in response to 50-ms steps from −124 to −54 in 10-mV increments. Wild-type cells had rapidly activating inward currents with reversal potentials close to the K+ equilibrium potential and a whole-cell conductance of 4.8 ± 1.5 nS (n = 46). In utricle hair cells from Kir2.1-deficient (Kir2.1−/−) mice, IK1 was absent at all stages examined. To identify the functional contribution of Kir2.1, we recorded membrane responses in current-clamp mode. Hair cells from Kir2.1−/− mice had significantly (P < 0.001) more depolarized resting potentials and larger, slower membrane responses than those of wild-type cells. These data suggest that Kir2.1 is required for IK1 in type II utricle hair cells and contributes to hyperpolarized resting potentials and fast, small amplitude receptor potentials in response to current inputs, such as those evoked by hair bundle deflections. PMID:22496522

Vestibular function in families with inherited autosomal dominant hearing loss

PubMed Central

Street, Valerie A.; Kallman, Jeremy C.; Strombom, Paul D.; Bramhall, Naomi F.; Phillips, James O.

2008-01-01

The inner ear contains the developmentally related cochlea and peripheral vestibular labyrinth. Given the similar physiology between these two organs, hearing loss and vestibular dysfunction may be expected to occur simultaneously in individuals segregating mutations in inner ear genes. Twenty-two different genes have been discovered that when mutated lead to non-syndromic autosomal dominant hearing loss. A review of the literature indicates that families segregating mutations in 13 of these 22 genes have undergone formal clinical vestibular testing. Formal assessment revealed vestibular dysfunction in families with mutations in ten of these 13 genes. Remarkably, only families with mutations in the COCH and MYO7A genes self-report considerable vestibular challenges. Families segregating mutations in the other eight genes do not self-report significant balance problems and appear to compensate well in everyday life for vestibular deficits discovered during formal clinical vestibular assessment. An example of a family (referred to as the HL1 family) with progressive hearing loss and clinically-detected vestibular hypofunction that does not report vestibular symptoms is described in this review. Notably, one member of the HL1 family with clinically-detected vestibular hypofunction reached the summit of Mount Kilimanjaro. PMID:18776598

Cyclin D1 expression and facial function outcome after vestibular schwannoma surgery.

PubMed

Lassaletta, Luis; Del Rio, Laura; Torres-Martin, Miguel; Rey, Juan A; Patrón, Mercedes; Madero, Rosario; Roda, Jose Maria; Gavilan, Javier

2011-01-01

The proto-oncogen cyclin D1 has been implicated in the development and behavior of vestibular schwannoma. This study evaluates the association between cyclin D1 expression and other known prognostic factors in facial function outcome 1 year after vestibular schwannoma surgery. Sixty-four patients undergoing surgery for vestibular schwannoma were studied. Immunohistochemistry analysis was performed with anticyclin D1 in all cases. Cyclin D1 expression, as well as other demographic, clinical, radiologic, and intraoperative data, was correlated with 1-year postoperative facial function. Good 1-year facial function (Grades 1-2) was achieved in 73% of cases. Cyclin D1 expression was found in 67% of the tumors. Positive cyclin D1 staining was more frequent in patients with Grades 1 to 2 (75%) than in those with Grades 3 to 6 (25%). Other significant variables were tumor volume and facial nerve stimulation after tumor resection. The area under the receiver operating characteristics curve increased when adding cyclin D1 expression to the multivariate model. Cyclin D1 expression is associated to facial outcome after vestibular schwannoma surgery. The prognostic value of cyclin D1 expression is independent of tumor size and facial nerve stimulation at the end of surgery.

The Effects of Aging on Clinical Vestibular Evaluations

PubMed Central

Maheu, Maxime; Houde, Marie-Soleil; Landry, Simon P.; Champoux, François

2015-01-01

Balance disorders are common issues for aging populations due to the effects of normal aging on peripheral vestibular structures. These changes affect the results of vestibular function evaluations and make the interpretation of these results more difficult. The objective of this article is to review the current state of knowledge of clinically relevant vestibular measures. We will first focus on otolith function assessment methods cervical-VEMP (cVEMP) and ocular-VEMP (oVEMP), then the caloric and video-head impulse test (vHIT) methods for semicircular canals assessment. cVEMP and oVEMP are useful methods, though research on the effects of age for some parameters are still inconclusive. vHIT results are largely independent of age as compared to caloric stimulation and should therefore be preferred for the evaluation of the semicircular canals function. PMID:26441824

[Peripheral, central and functional vertigo syndromes].

PubMed

Strupp, M; Dieterich, M; Zwergal, A; Brandt, T

2015-12-01

Depending on the temporal course, three forms of vertigo syndrome can be differentiated: 1) vertigo attacks, e.g. benign paroxysmal positional vertigo (BPPV), Menière's disease and vestibular migraine, 2) acute spontaneous vertigo lasting for days, e.g. acute unilateral vestibulopathy, brainstem or cerebellar infarction and 3) symptoms lasting for months or years, e.g. bilateral vestibulopathy and functional vertigo. The specific therapy of the various syndromes is based on three principles: 1) physical treatment with liberatory maneuvers for BPPV and balance training for vestibular deficits, 2) pharmacotherapy, e.g. for acute unilateral vestibulopathy (corticosteroids) and Menière's disease (transtympanic administration of gentamicin or steroids and high-dose betahistine therapy); placebo-controlled pharmacotherapy studies are currently being carried out for acute unilateral vestibulopathy, vestibular paroxysmia, prophylaxis of BPPV, vestibular migraine, episodic ataxia type 2 and cerebellar ataxia; 3) psychotherapy for functional dizziness.

State Anxiety Subjective Imbalance and Handicap in Vestibular Schwannoma.

PubMed

Saman, Yougan; Mclellan, Lucie; Mckenna, Laurence; Dutia, Mayank B; Obholzer, Rupert; Libby, Gerald; Gleeson, Michael; Bamiou, Doris-Eva

2016-01-01

Evidence is emerging for a significant clinical and neuroanatomical relationship between balance and anxiety. Research has suggested a potentially priming effect with anxiety symptoms predicting a worsening of balance function in patients with underlying balance dysfunction. We propose to show that a vestibular stimulus is responsible for an increase in state anxiety, and there is a relationship between increased state anxiety and worsening balance function. (1) To quantify state anxiety following a vestibular stimulus in patients with a chronic vestibular deficit. (2) To determine if state anxiety during a vestibular stimulus would correlate with the severity of chronic balance symptoms and handicap. Two separate cohorts of vestibular schwannoma (VS) patients underwent vestibular tests (electronystagmography, cervical and ocular vestibular evoked myogenic potentials, and caloric responses) and questionnaire assessments [vertigo handicap questionnaire (VHQ), vertigo symptom scale (VSS), and state-trait anxiety inventory (STAIY)]. Fifteen post-resection VS patients, with complete unilateral vestibular deafferentation, were assessed at a minimum of 6 months after surgery in Experiment 1 (Aim 1). Forty-five patients with VS in situ formed the cohort for Experiment 2 (Aim 2). Experiment 1: VS subjects (N = 15) with a complete post-resection unilateral vestibular deafferentation completed a state anxiety questionnaire before caloric assessment and again afterward with the point of maximal vertigo as the reference (Aim 1). Experiment 2: state anxiety measured at the point of maximal vertigo following a caloric assessment was compared between two groups of patients with VS in situ presenting with balance symptoms (Group 1, N = 26) and without balance symptoms (Group 2, N = 11) (Aim 2). The presence of balance symptoms was defined as having a positive score on the VSS-VER. In Experiment 1, a significant difference (p < 0.01) was found when comparing STAIY at baseline and at the peak of the subjective vertiginous response in post-resection patients with a unilateral vestibular deafferentation. In Experiment 2, VS in situ patients with balance symptoms had significantly worse state anxiety at the peak vertiginous response than patients without balance symptoms (p < 0.001), as did patients with a balance-related handicap (p < 0.001). Anxiety symptoms during a vestibular stimulus may contribute to a priming effect that could explain worsening balance function.

Different contributions of platelet-activating factor and nitric oxide in long-term potentiation of the rat medial vestibular nuclei.

PubMed

Pettorossi, V E; Grassi, S

2001-01-01

In rat brainstem slices, we investigated the differential role of nitric oxide (NO) and platelet-activating factor (PAF) in long-term potentiation (LTP) induced in the ventral portion of the medial vestibular nuclei (MVN) by high-frequency stimulation (HFS) of the primary vestibular afferents. The NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) and the PAF receptor antagonist ginkgolide B (BN-52021) were administered before and after induction of potentiation. The effect of carboxy-PTIO was to completely prevent LTP. By contrast, BN-52021 only reduced the amplitude of HFS potentiation, which could develop fully at the drug washout or decline to zero, becoming a short-term phenomenon, in the case of long-lasting PAF receptor block. Both drugs, when given after HFS, had no effect on the already established potentiation, but whilst BN-52021 showed an influence within 5 min of the LTP induction, carboxy-PTIO did not affect the response once HFS was delivered. Moreover, we showed that the NO donor, sodium nitroprusside, and methylcarbamyl PAF (mc-PAF) induced LTP which was associated with an increase in glutamate release as shown by reduction in the paired-pulse facilitation ratio. The mc-PAF LTP was prevented by the NO scavenger, while NO LTP was only reduced by BN-52021. We suggest that NO and PAF are implicated as retrograde messengers in two different phases of vestibular LTP: NO in the induction phase; and PAF in the full expression phase.

A model describing vestibular detection of body sway motion.

NASA Technical Reports Server (NTRS)

Nashner, L. M.

1971-01-01

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.

Functional, Structural, and Neurotoxicity Biomarkers in Integrative Assessment of Concussions

PubMed Central

Dambinova, Svetlana A.; Maroon, Joseph C.; Sufrinko, Alicia M.; Mullins, John David; Alexandrova, Eugenia V.; Potapov, Alexander A.

2016-01-01

Concussion is a complex, heterogeneous process affecting the brain. Accurate assessment and diagnosis and appropriate management of concussion are essential to ensure that athletes do not prematurely return to play or others to work or active military duty, risking re-injury. To date, clinical diagnosis relies primarily on evaluating subjects for functional impairment using instruments that include neurocognitive testing, subjective symptom report, and neurobehavioral assessments, such as balance and vestibular-ocular reflex testing. Structural biomarkers, defined as advanced neuroimaging techniques and biomarkers assessing neurotoxicity and immunoexcitotoxicity, may complement the use of functional biomarkers. We hypothesize that neurotoxicity AMPA, NMDA, and kainite receptor biomarkers might be utilized as a part of comprehensive approach to concussion evaluations, with the goal of increasing diagnostic accuracy and facilitating treatment planning and prognostic assessment. PMID:27761129

Vestibular function assessment using the NIH Toolbox

PubMed Central

Schubert, Michael C.; Whitney, Susan L.; Roberts, Dale; Redfern, Mark S.; Musolino, Mark C.; Roche, Jennica L.; Steed, Daniel P.; Corbin, Bree; Lin, Chia-Cheng; Marchetti, Greg F.; Beaumont, Jennifer; Carey, John P.; Shepard, Neil P.; Jacobson, Gary P.; Wrisley, Diane M.; Hoffman, Howard J.; Furman, Gabriel; Slotkin, Jerry

2013-01-01

Objective: Development of an easy to administer, low-cost test of vestibular function. Methods: Members of the NIH Toolbox Sensory Domain Vestibular, Vision, and Motor subdomain teams collaborated to identify 2 tests: 1) Dynamic Visual Acuity (DVA), and 2) the Balance Accelerometry Measure (BAM). Extensive work was completed to identify and develop appropriate software and hardware. More than 300 subjects between the ages of 3 and 85 years, with and without vestibular dysfunction, were recruited and tested. Currently accepted gold standard measures of static visual acuity, vestibular function, dynamic visual acuity, and balance were performed to determine validity. Repeat testing was performed to examine reliability. Results: The DVA and BAM tests are affordable and appropriate for use for individuals 3 through 85 years of age. The DVA had fair to good reliability (0.41–0.94) and sensitivity and specificity (50%–73%), depending on age and optotype chosen. The BAM test was moderately correlated with center of pressure (r = 0.42–0.48) and dynamic posturography (r = −0.48), depending on age and test condition. Both tests differentiated those with and without vestibular impairment and the young from the old. Each test was reliable. Conclusion: The newly created DVA test provides a valid measure of visual acuity with the head still and moving quickly. The novel BAM is a valid measure of balance. Both tests are sensitive to age-related changes and are able to screen for impairment of the vestibular system. PMID:23479540

Diversity of vestibular nuclei neurons targeted by cerebellar nodulus inhibition

PubMed Central

Meng, Hui; Blázquez, Pablo M; Dickman, J David; Angelaki, Dora E

2014-01-01

Abstract A functional role of the cerebellar nodulus and ventral uvula (lobules X and IXc,d of the vermis) for vestibular processing has been strongly suggested by direct reciprocal connections with the vestibular nuclei, as well as direct vestibular afferent inputs as mossy fibres. Here we have explored the types of neurons in the macaque vestibular nuclei targeted by nodulus/ventral uvula inhibition using orthodromic identification from the caudal vermis. We found that all nodulus-target neurons are tuned to vestibular stimuli, and most are insensitive to eye movements. Such non-eye-movement neurons are thought to project to vestibulo-spinal and/or thalamo-cortical pathways. Less than 20% of nodulus-target neurons were sensitive to eye movements, suggesting that the caudal vermis can also directly influence vestibulo-ocular pathways. In general, response properties of nodulus-target neurons were diverse, spanning the whole continuum previously described in the vestibular nuclei. Most nodulus-target cells responded to both rotation and translation stimuli and only a few were selectively tuned to translation motion only. Other neurons were sensitive to net linear acceleration, similar to otolith afferents. These results demonstrate that, unlike the flocculus and ventral paraflocculus which target a particular cell group, nodulus/ventral uvula inhibition targets a large diversity of cell types in the vestibular nuclei, consistent with a broad functional significance contributing to vestibulo-ocular, vestibulo-thalamic and vestibulo-spinal pathways. PMID:24127616

Gait ataxia in humans: vestibular and cerebellar control of dynamic stability.

PubMed

Schniepp, Roman; Möhwald, Ken; Wuehr, Max

2017-10-01

During human locomotion, vestibular feedback control is fundamental for maintaining dynamic stability and adapting the gait pattern to external circumstances. Within the supraspinal locomotor network, the cerebellum represents the key site for the integration of vestibular feedback information. The cerebellum is further important for the fine-tuning and coordination of limb movements during walking. The aim of this review article is to highlight the shared structural and functional sensorimotor principles in vestibular and cerebellar locomotion control. Vestibular feedback for the maintenance of dynamic stability is integrated into the locomotor pattern via midline, caudal cerebellar structures (vermis, flocculonodular lobe). Hemispheric regions of the cerebellum facilitate feed-forward control of multi-joint coordination and higher locomotor functions. Characteristic features of the gait disorder in patients with vestibular deficits or cerebellar ataxia are increased levels of spatiotemporal gait variability in the fore-aft and the medio-lateral gait dimension. In the fore-aft dimension, pathologic increases of gait fluctuations critically depend on the locomotion speed and predominantly manifest during slow walking velocities. This feature is associated with an increased risk of falls in both patients with vestibular hypofunction as well as patients with cerebellar ataxia. Pharmacological approaches for the treatment of vestibular or cerebellar gait ataxia are currently not available. However, new promising options are currently tested in randomized, controlled trials (fampridine/FACEG; acetyl-DL-leucine/ALCAT).

A quantitative survey of gravity receptor function in mutant mouse strains.

PubMed

Jones, Sherri M; Johnson, Kenneth R; Yu, Heping; Erway, Lawrence C; Alagramam, Kumar N; Pollak, Natasha; Jones, Timothy A

2005-12-01

The purpose of this research was to identify vestibular deficits in mice using linear vestibular evoked potentials (VsEPs). VsEP thresholds, peak latencies, and peak amplitudes from 24 strains with known genetic mutations and 6 inbred background strains were analyzed and descriptive statistics generated for each strain. Response parameters from mutant homozygotes were compared with heterozygote and/or background controls and all strain averages were contrasted to normative ranges. Homozygotes of the following recessive mutations had absent VsEPs at the ages tested: Espn(je), Atp2b2dfw-2J, Spnb4qv-lnd2J, Spnb4qv-3J, Myo7ash1, Tmie(sr), Myo6sv, jc, Pcdh15av-J, Pcdh15av-2J, Pcdh15av-3J, Cdh23v-2J, Sans(js), hr, Kcne1pkr and Pou3f4del. These results suggest profound gravity receptor deficits for these homozygotes, which is consistent with the structural deficits that have been documented for many of these strains. Homozygotes of Catna2cdf, Grid2ho4J, Wnt1sw, qk, and Mbpshi strains and heterozygotes of Grid2lc had measurable VsEPs but one or more response parameters differed from the respective control group (heterozygote or background strain) or were outside normal ranges. For example, qk and Mbpshi homozygotes showed significantly prolonged latencies consistent with the abnormal myelin that has been described for these strains. Prolonged latencies may suggest deficits in neural conduction; elevated thresholds suggest reduced sensitivity, and reduced amplitudes may be suggestive for reduced neural synchrony. One mutation, Otx1jv, had all VsEP response parameters within normal limits--an expected finding because the abnormality in Otxljv is presumably restricted to the lateral semicircular canal. Interestingly, some heterozygote groups also showed abnormalities in one or more VsEP response parameters, suggesting that vestibular dysfunction, although less severe, may be present in some heterozygous animals.

Do post-stroke patients benefit from robotic verticalization? A pilot-study focusing on a novel neurophysiological approach.

PubMed

Calabrò, Rocco Salvatore; Naro, Antonino; Russo, Margherita; Leo, Antonino; Balletta, Tina; Saccá, Ileana; De Luca, Rosaria; Bramanti, Placido

2015-01-01

Tilt-table equipped with the dynamic foot-support (ERIGO) and the functional electric stimulation could be a safe and suitable device for stabilization of vital signs, increasing patient's motivation for further recovery, decreasing the duration of hospitalization, and accelerating the adaptation to vertical posture in bedridden patients with brain-injury. Moreover, it is conceivable that verticalization may improve cognitive functions, and induce plastic changes at sensory motor and vestibular system level that may in turn facilitate motor functional recovery. To test the safety and effectiveness of ERIGO treatment on motor and cognitive functions, cortical plasticity within vestibular and sensory-motor systems in a bedridden post-stroke sample. 20 patients were randomly divided in two groups that performed ERIGO training (30 sessions) (G1) or physiotherapist-assisted verticalization training (same duration) (G2), beyond conventional neurorehabilitation treatment. Motor and cognitive functions as well as sensory-motor and vestibular system plasticity were investigated either before (T0) or after (T1) the rehabilitative protocols. Both the verticalization treatments were well-tolerated. Notably, the G1 patients had a significant improvement in cognitive function (p = 0.03), global motor function (p = 0.006), sensory-motor (p < 0.001) and vestibular system plasticity (p = 0.02) as compared to G2. ERIGO training could be a valuable tool for the adaptation to the vertical position with a better global function improvement, as also suggested by the sensory-motor and vestibular system plasticity induction.

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

PubMed Central

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

2014-01-01

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

Transtympanic gentamicin and fibrin tissue adhesive for treatment of unilateral Menière's disease: effects on vestibular function.

PubMed

Casani, Augusto; Nuti, Daniele; Franceschini, Stefano Sellari; Gaudini, Elisa; Dallan, Iacopo

2005-12-01

To determine the effects of transtympanic injections, with a mixture composed of gentamicin and fibrin tissue adhesive (FTA), on vestibular function of patients with intractable unilateral Menière's disease. This was an open, prospective study. The study was performed at 2 tertiary referral centers. Twenty-six patients affected by "definite" unilateral Menière's disease, unresponsive to medical therapy for at least 6 months, were enrolled. A buffered gentamicin solution mixed with FTA was injected in the middle ear until the development of bedside vestibular hypofunction signs and/or caloric weakness in the treated ear. Vestibular function was evaluated by 3 bedside vestibular tests (observation of spontaneous nystagmus, head shaking test, and head thrust test) and by a caloric test. Tests were performed on days 10 and 30 after completion of treatment. Tests were also performed 3, 6, and 12 months from completion of the gentamicin-FTA protocol. The effects of treatment were also assessed in terms of hearing levels, control of vertigo, and disability status. In 22 of the 26 patients, only 1 gentamicin-FTA injection was necessary to obtain 1 or more signs indicating a reduction of the vestibular function in the treated ear. Four patients needed another treatment because of the persistence of their incapacitating symptoms during the follow-up. Four patients needed more than 1 injection to obtain a vestibular hypofunction. None of the patients who received 1 or 2 injections presented hearing loss in direct temporal relationship to the treatment. A mixture of gentamicin and fibrin glue makes it possible to considerably reduce the number of administrations in patients with intractable unilateral Menière's disease. Spontaneous nystagmus, post head shaking nystagmus, and a head thrust sign are the clinical signs that indicate onset or progression of unilateral vestibular hypofunction. These signs were obtained with only 1 injection in 81% of patients.

Altered resting-state functional connectivity in patients with chronic bilateral vestibular failure.

PubMed

Göttlich, Martin; Jandl, Nico M; Wojak, Jann F; Sprenger, Andreas; von der Gablentz, Janina; Münte, Thomas F; Krämer, Ulrike M; Helmchen, Christoph

2014-01-01

Patients with bilateral vestibular failure (BVF) suffer from gait unsteadiness, oscillopsia and impaired spatial orientation. Brain imaging studies applying caloric irrigation to patients with BVF have shown altered neural activity of cortical visual-vestibular interaction: decreased bilateral neural activity in the posterior insula and parietal operculum and decreased deactivations in the visual cortex. It is unknown how this affects functional connectivity in the resting brain and how changes in connectivity are related to vestibular impairment. We applied a novel data driven approach based on graph theory to investigate altered whole-brain resting-state functional connectivity in BVF patients (n= 22) compared to age- and gender-matched healthy controls (n= 25) using resting-state fMRI. Changes in functional connectivity were related to subjective (vestibular scores) and objective functional parameters of vestibular impairment, specifically, the adaptive changes during active (self-guided) and passive (investigator driven) head impulse test (HIT) which reflects the integrity of the vestibulo-ocular reflex (VOR). BVF patients showed lower bilateral connectivity in the posterior insula and parietal operculum but higher connectivity in the posterior cerebellum compared to controls. Seed-based analysis revealed stronger connectivity from the right posterior insula to the precuneus, anterior insula, anterior cingulate cortex and the middle frontal gyrus. Excitingly, functional connectivity in the supramarginal gyrus (SMG) of the inferior parietal lobe and posterior cerebellum correlated with the increase of VOR gain during active as compared to passive HIT, i.e., the larger the adaptive VOR changes the larger was the increase in regional functional connectivity. Using whole brain resting-state connectivity analysis in BVF patients we show that enduring bilateral deficient or missing vestibular input leads to changes in resting-state connectivity of the brain. These changes in the resting brain are robust and task-independent as they were found in the absence of sensory stimulation and without a region-related a priori hypothesis. Therefore they may indicate a fundamental disease-related change in the resting brain. They may account for the patients' persistent deficits in visuo-spatial attention, spatial orientation and unsteadiness. The relation of increasing connectivity in the inferior parietal lobe, specifically SMG, to improvement of VOR during active head movements reflects cortical plasticity in BVF and may play a clinical role in vestibular rehabilitation.

Extending the Functional Cerebral Systems Theory of Emotion to the Vestibular Modality: A Systematic and Integrative Approach

ERIC Educational Resources Information Center

Carmona, Joseph E.; Holland, Alissa K.; Harrison, David W.

2009-01-01

Throughout history, vestibular and emotional dysregulation have often manifested together in clinical settings, with little consideration that they may have a common basis. Regarding vestibular mechanisms, the role of brainstem and cerebellar structures has been emphasized in the neurological literature, whereas emotion processing in the cerebral…

Physical Therapy Principles in Rehabilitation

PubMed Central

Sparto, Patrick J.

2016-01-01

The use of vestibular rehabilitation for persons with balance and vestibular disorders is used to improve function and decrease dizziness symptoms. Principles of a vestibular rehabilitation program are described including common exercises and outcome measures used to report change. A review of negative and positive predictive factors related to recovery is also provided. PMID:22027077

Sympathetic Arousal to a Vestibular Stressor in High and Low Hostile Men

ERIC Educational Resources Information Center

Carmona, Joseph E.; Holland, Alissa K.; Stratton, Harrison J.; Harrison, David W.

2008-01-01

The aim of the present experiment was to extend the literature on hostility and a cerebral systems based model of sympathetic arousal to a vestibular-based stress. Several authors have concluded that autonomic stress reactivity in high hostile individuals must be interpersonally based, whereas healthy vestibular system functioning does not depend…

Vestibulo-Cervico-Ocular Responses and Tracking Eye Movements after Prolonged Exposure to Microgravity

NASA Technical Reports Server (NTRS)

Kornilova, L. N.; Naumov, I. A.; Azarov, K. A.; Sagalovitch, S. V.; Reschke, Millard F.; Kozlovskaya, I. B.

2007-01-01

The vestibular function and tracking eye movements were investigated in 12 Russian crew members of ISS missions on days 1(2), 4(5-6), and 8(9-10) after prolonged exposure to microgravity (126 to 195 days). The spontaneous oculomotor activity, static torsional otolith-cervico-ocular reflex, dynamic vestibulo-cervico-ocular responses, vestibular reactivity, tracking eye movements, and gaze-holding were studied using videooculography (VOG) and electrooculography (EOG) for parallel eye movement recording. On post-flight days 1-2 (R+1-2) some cosmonauts demonstrated: - an increased spontaneous oculomotor activity (floating eye movements, spontaneous nystagmus of the typical and atypical form, square wave jerks, gaze nystagmus) with the head held in the vertical position; - suppressed otolith function (absent or reduced by one half amplitude of torsional compensatory eye counter-rolling) with the head inclined statically right- or leftward by 300; - increased vestibular reactivity (lowered threshold and increased intensity of the vestibular nystagmus) during head turns around the longitudinal body axis at 0.125 Hz; - a significant change in the accuracy, velocity, and temporal characteristics of the eye tracking. The pattern, depth, dynamics, and velocity of the vestibular function and tracking eye movements recovery varied with individual participants in the investigation. However, there were also regular responses during readaptation to the normal gravity: - suppression of the otolith function was typically accompanied by an exaggerated vestibular reactivity; - the structure of visual tracking (the accuracy of fixational eye rotations, smooth tracking, and gaze-holding) was disturbed (the appearance of correcting saccades, the transition of smooth tracking to saccadic tracking) only in those cosmonauts who, in parallel to an increased reactivity of the vestibular input, also had central changes in the oculomotor system (spontaneous nystagmus, gaze nystagmus).

Stereotactic radiotherapy of vestibular schwannoma : Hearing preservation, vestibular function, and local control following primary and salvage radiotherapy.

PubMed

Putz, Florian; Müller, Jan; Wimmer, Caterina; Goerig, Nicole; Knippen, Stefan; Iro, Heinrich; Grundtner, Philipp; Eyüpoglu, Ilker; Rössler, Karl; Semrau, Sabine; Fietkau, Rainer; Lettmaier, Sebastian

2017-03-01

The aim of this publication is to present long-term data on functional outcomes and tumor control in a cohort of 107 patients treated with stereotactic radiotherapy (RT) for vestibular schwannoma. Included were 107 patients with vestibular schwannoma (primary or recurrent following resection) treated with stereotactic RT (either fractioned or single-dose radiosurgery) between October 2002 and December 2013. Local control and functional outcomes were determined. Analysis of hearing preservation was limited to a subgroup of patients with complete audiometric data collected before treatment and during follow-up. Vestibular function test (FVT) results could be analyzed in a subset of patients and were compared to patient-reported dizziness. After a mean follow-up of 46.3 months, actuarial local control for the whole cohort was 100% after 2, 97.6% after 5, and 94.1% after 10 years. In patients with primary RT, serviceable hearing was preserved in 72%. Predictors for preservation of serviceable hearing in multivariate analysis were time of follow-up (odds ratio, OR = 0.93 per month; p = 0.021) and pre-RT tumor size (Koos stage I-IIa vs. IIb-IV; OR = 0.15; p = 0.031). Worsening of FVT results was recorded in 17.6% (N = 3). Profound discrepancy of patient-reported dizziness and FVT results was observed after RT. In patients with primary RT, worsening of facial nerve function occurred in 1.7% (N = 1). Stereotactic RT of vestibular schwannoma provides good functional outcomes and high control rates. Dependence of hearing preservation on time of follow-up and initial tumor stage has to be considered.

Long-term potentiation and depression after unilateral labyrinthectomy in the medial vestibular nucleus of rats.

PubMed

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

2003-01-01

We previously demonstrated in rat brainstem slices that high-frequency stimulation (HFS) of the vestibular afferents induces long-term potentiation (LTP) in the ventral part (Vp) of the medial vestibular nucleus (MVN) and long-term depression (LTD) in the dorsal part (Dp). Both LTP and LTD depend on N-methyl-D-aspartate receptor activation, which increases synaptic efficacy; however, in the Dp, LTP reverses to LTD because of the activation of gamma-aminobutyric acid-ergic neurons. Here we show that the probability of inducing long-term effects in the MVN of rat brainstem slices is altered after unilateral labyrinthectomy (UL). In fact, LTP occurs less frequently in the ventral contra-lesional side compared with sham-operated rats. In the dorsal ipsi-lesional side, LTD is reduced and LTP enhanced, while the opposite occurs in the dorsal contra-lesional side. These changes in synaptic plasticity may be useful for re-balancing the tonic discharge of the MVN of the two sides during vestibular compensation, and for enhancing the dynamic responses of the deafferented MVN neurons in the long term.

The functional head impulse test: preliminary data.

PubMed

Corallo, Giulia; Versino, Maurizio; Mandalà, Marco; Colnaghi, Silvia; Ramat, Stefano

2018-06-04

The functional head impulse test is a new test of vestibular function based on the ability to recognize the orientation of a Landolt C optotype that briefly appears on a computer screen during passive head impulses imposed by the examiner over a range of head accelerations. Here, we compare its results with those of the video head impulse test on a population of vestibular neuritis patients recorded acutely and after 3 months from symptoms onset. The preliminary results presented here show that while both tests are able to identify the affected labyrinth and to show a recovery of vestibular functionality at 3 months, the two tests are not redundant, but complementary.

Evidence for vestibular regulation of autonomic functions in a mouse genetic model

NASA Technical Reports Server (NTRS)

Murakami, Dean M.; Erkman, Linda; Hermanson, Ola; Rosenfeld, Michael G.; Fuller, Charles A.

2002-01-01

Physiological responses to changes in the gravitational field and body position, as well as symptoms of patients with anxiety-related disorders, have indicated an interrelationship between vestibular function and stress responses. However, the relative significance of cochlear and vestibular information in autonomic regulation remains unresolved because of the difficulties in distinguishing the relative contributions of other proprioceptive and interoceptive inputs, including vagal and somatic information. To investigate the role of cochlear and vestibular function in central and physiological responses, we have examined the effects of increased gravity in wild-type mice and mice lacking the POU homeodomain transcription factor Brn-3.1 (Brn-3bPou4f3). The only known phenotype of the Brn-3.1(-/-) mouse is related to hearing and balance functions, owing to the failure of cochlear and vestibular hair cells to differentiate properly. Here, we show that normal physiological responses to increased gravity (2G exposure), such as a dramatic drop in body temperature and concomitant circadian adjustment, were completely absent in Brn-3.1(-/-) mice. In line with the lack of autonomic responses, the massive increase in neuronal activity after 2G exposure normally detected in wild-type mice was virtually abolished in Brn-3.1(-/-) mice. Our results suggest that cochlear and vestibular hair cells are the primary regulators of autonomic responses to altered gravity and provide genetic evidence that these cells are sufficient to alter neural activity in regions involved in autonomic and neuroendocrine control.

Activation of PAF-synthesizing enzymes in rat brain stem slices after LTP induction in the medial vestibular nuclei.

PubMed

Francescangeli, Ermelinda; Grassi, Silvarosa; Pettorossi, Vito E; Goracci, Gianfrancesco

2002-11-01

LysoPAF acetyltransferase (lysoPAF-AT) and PAF-synthesizing phosphocholinetransferase (PAF-PCT) are the two enzymes which catalyze the final reactions for the synthesis of PAF. Their activities, assayed in the homogenate of rat brain stem slices and under their optimal conditions, increased 5 min after high frequency stimulation of vestibular afferents, inducing LTP in the medial vestibular nuclei. The activity of phosphatidylcholine-synthesizing phosphocholinetransferase, was not affected. Sixty minutes from the induction of LTP, PAF-PCT activity, but not that of lysoPAF-AT, was still significantly higher with respect to 5 min test stimulated control. We used AP-5 to verify whether this increase was strictly dependent upon LTP induction, which requires NMDA receptor activation. In AP-5 treated slices, lysoPAF-acetyltransferase and PAF-synthesizing phosphocholinetransferase activities increased, but they were reduced after high frequency stimulation under AP-5. In conclusion, we have demonstrated that the activities of PAF-synthesizing enzymes are activated soon after the induction of LTP and that this effect is linked to the activation of NMDA-receptors. We suggest that the enzyme activation by AP-5, preventing LTP, might be due to glutamate enhancement but, in neurons showing LTP and under normal conditions, the activation of potentiation mechanisms is critical for the enhancement of enzyme activities.

Gap junction systems in the rat vestibular labyrinth: immunohistochemical and ultrastructural analysis.

PubMed

Kikuchi, T; Adams, J C; Paul, D L; Kimura, R S

1994-09-01

The distribution of gap junctions within the vestibular labyrinth was investigated using immunohistochemistry and transmission electron microscopy. Connexin26-like immunoreactivity was observed among supporting cells in each vestibular sensory epithelium. Reaction product was also present in the transitional epithelium of each vestibular endorgan and in the planum semilunatum of crista ampullaris. No connexin26-like immunoreactivity was observed among thin wall epithelial cells or among vestibular dark cells. In addition, fibrocytes within vestibular connective tissue were positively immunostained. Reaction product was also detected in the melanocyte area just beneath dark cells. Ultrastructural observations indicated that a gap junction network of vestibular supporting cells extends to the transitional epithelium and planum semilunatum and forms an isolated epithelial cell gap junction system in each vestibular endorgan. In contrast, no gap junctions were found among wall epithelial cells or among dark cells. Fibrocytes and melanocytes were coupled by gap junctions and belong to the connective tissue cell gap junction system, which is continuous throughout the vestibular system and the cochlea. The possible functional significance of these gap junction systems is discussed.

Uncoupling VOR and vestibuloautonomic retention to Coriolis acceleration training in student pilots and control subjects.

PubMed

Wang, Linjie; Cao, Yi; Tan, Cheng; Zhao, Qi; He, Siyang; Niu, Dongbin; Tang, Guohua; Zou, Peng; Xing, Lei

2017-01-01

Explore the different vestibular physiologic response retention patterns after Coriolis acceleration training in student pilots and extend the results for use with Chinese astronauts in the future. Twelve healthy control male subjects were screened from males familiar with vestibular training and who physically resembled the astronauts. Fourteen student pilots were selected from 23 participants by rotational vestibular function tests. All subjects were exposed to five-day continuous or intermittent Coriolis acceleration training. Subjective motion sickness (MS) symptom scores, electrocardiography, electrogastrography (EGG), post-rotatory nystagmus and renin-angiotensin system responses were measured before, during and after rotational vestibular function tests at different times after vestibular training. Subjects could tolerate 10 min or 15 min of vestibular with mild MS symptoms. Retention of vestibular autonomic responses (retention of MS symptom scores, heart rate variability, power density of EGG, variations in levels of arginine vasopressin) were approximately 1 week for control subjects and approximately 5 weeks for student pilots. Decreases in slow-phase velocity of post-rotatory nystagmus were maintained for 14 weeks for control subjects and 9 weeks for student pilots. Retention of the vestibulo-autonomic reaction after vestibular training was different for control subjects and student pilots. All parameters related to autonomic responses could be maintained at low levels after vestibular training for approximately 1 week for control subjects and approximately 5 weeks for student pilots. Uncoupling patterns between post-rotatory nystagmus and the vestibulo-autonomic reaction may be helpful in the design of clinical rehabilitation plans for balance-disorder patients and for exploration of artificial gravity in future space missions.

Enhancing vestibular function in the elderly with imperceptible electrical stimulation.

PubMed

Serrador, Jorge M; Deegan, Brian M; Geraghty, Maria C; Wood, Scott J

2018-01-10

Age-related loss of vestibular function can result in decrements in gaze stabilization and increased fall risk in the elderly. This study was designed to see if low levels of electrical stochastic noise applied transcutaneously to the vestibular system can improve a gaze stabilization reflex in young and elderly subject groups. Ocular counter-rolling (OCR) using a video-based technique was obtained in 16 subjects during low frequency passive roll tilts. Consistent with previous studies, there was a significant reduction in OCR gains in the elderly compared to the young group. Imperceptible stochastic noise significantly increased OCR in the elderly (Mean 23%, CI: 17-35%). Increases in OCR gain were greatest for those with lowest baseline gain and were negligible in those with normal gain. Since stimulation was effective at low levels undetectable to subjects, stochastic noise may provide a new treatment alternative to enhance vestibular function, specifically otolith-ocular reflexes, in the elderly or patient populations with reduced otolith-ocular function.

In Vivo Analysis of Lrig Genes Reveals Redundant and Independent Functions in the Inner Ear

PubMed Central

del Rio, Tony; Nishitani, Allison M.; Yu, Wei-Ming; Goodrich, Lisa V.

2013-01-01

Lrig proteins are conserved transmembrane proteins that modulate a variety of signaling pathways from worm to humans. In mammals, there are three family members – Lrig1, Lrig2, and Lrig3 – that are defined by closely related extracellular domains with a similar arrangement of leucine rich repeats and immunoglobulin domains. However, the intracellular domains show little homology. Lrig1 inhibits EGF signaling through internalization and degradation of ErbB receptors. Although Lrig3 can also bind ErbB receptors in vitro, it is unclear whether Lrig2 and Lrig3 exhibit similar functions to Lrig1. To gain insights into Lrig gene functions in vivo, we compared the expression and function of the Lrigs in the inner ear, which offers a sensitive system for detecting effects on morphogenesis and function. We find that all three family members are expressed in the inner ear throughout development, with Lrig1 and Lrig3 restricted to subsets of cells and Lrig2 expressed more broadly. Lrig1 and Lrig3 overlap prominently in the developing vestibular apparatus and simultaneous removal of both genes disrupts inner ear morphogenesis. This suggests that these two family members act redundantly in the otic epithelium. In contrast, although Lrig1 and Lrig2 are frequently co-expressed, Lrig1−/−;Lrig2−/− double mutant ears show no enhanced structural abnormalities. At later stages, Lrig1 expression is sustained in non-sensory tissues, whereas Lrig2 levels are enhanced in neurons and sensory epithelia. Consistent with these distinct expression patterns, Lrig1 and Lrig2 mutant mice exhibit different forms of impaired auditory responsiveness. Notably, Lrig1−/−;Lrig2−/− double mutant mice display vestibular deficits and suffer from a more severe auditory defect that is accompanied by a cochlear innervation phenotype not present in single mutants. Thus, Lrig genes appear to act both redundantly and independently, with Lrig2 emerging as the most functionally distinct family member. PMID:24086156

Vestibular animal models: contributions to understanding physiology and disease.

PubMed

Straka, Hans; Zwergal, Andreas; Cullen, Kathleen E

2016-04-01

Our knowledge of the vestibular sensory system, its functional significance for gaze and posture stabilization, and its capability to ensure accurate spatial orientation perception and spatial navigation has greatly benefitted from experimental approaches using a variety of vertebrate species. This review summarizes the attempts to establish the roles of semicircular canal and otolith endorgans in these functions followed by an overview of the most relevant fields of vestibular research including major findings that have advanced our understanding of how this system exerts its influence on reflexive and cognitive challenges encountered during daily life. In particular, we highlight the contributions of different animal models and the advantage of using a comparative research approach. Cross-species comparisons have established that the morpho-physiological properties underlying vestibular signal processing are evolutionarily inherent, thereby disclosing general principles. Based on the documented success of this approach, we suggest that future research employing a balanced spectrum of standard animal models such as fish/frog, mouse and primate will optimize our progress in understanding vestibular processing in health and disease. Moreover, we propose that this should be further supplemented by research employing more "exotic" species that offer unique experimental access and/or have specific vestibular adaptations due to unusual locomotor capabilities or lifestyles. Taken together this strategy will expedite our understanding of the basic principles underlying vestibular computations to reveal relevant translational aspects. Accordingly, studies employing animal models are indispensible and even mandatory for the development of new treatments, medication and technical aids (implants) for patients with vestibular pathologies.

Do post-stroke patients benefit from robotic verticalization? A pilot-study focusing on a novel neurophysiological approach

PubMed Central

Calabrò, Rocco Salvatore; Naro, Antonino; Russo, Margherita; Leo, Antonino; Balletta, Tina; Saccá, Ileana; De Luca, Rosaria; Bramanti, Placido

2015-01-01

Abstract Background: Tilt-table equipped with the dynamic foot-support (ERIGO) and the functional electric stimulation could be a safe and suitable device for stabilization of vital signs, increasing patient’s motivation for further recovery, decreasing the duration of hospitalization, and accelerating the adaptation to vertical posture in bedridden patients with brain-injury. Moreover, it is conceivable that verticalization may improve cognitive functions, and induce plastic changes at sensory motor and vestibular system level that may in turn facilitate motor functional recovery. Objective: To test the safety and effectiveness of ERIGO treatment on motor and cognitive functions, cortical plasticity within vestibular and sensory-motor systems in a bedridden post-stroke sample. Methods: 20 patients were randomly divided in two groups that performed ERIGO training (30 sessions) (G1) or physiotherapist-assisted verticalization training (same duration) (G2), beyond conventional neurorehabilitation treatment. Motor and cognitive functions as well as sensory-motor and vestibular system plasticity were investigated either before (T0) or after (T1) the rehabilitative protocols. Results: Both the verticalization treatments were well-tolerated. Notably, the G1 patients had a significant improvement in cognitive function (p = 0.03), global motor function (p = 0.006), sensory-motor (p <  0.001) and vestibular system plasticity (p = 0.02) as compared to G2. Conclusions: ERIGO training could be a valuable tool for the adaptation to the vertical position with a better global function improvement, as also suggested by the sensory-motor and vestibular system plasticity induction. PMID:26410207

ACh-induced hyperpolarization and decreased resistance in mammalian type II vestibular hair cells.

PubMed

Poppi, Lauren A; Tabatabaee, Hessam; Drury, Hannah R; Jobling, Phillip; Callister, Robert J; Migliaccio, Americo A; Jordan, Paivi M; Holt, Joseph C; Rabbitt, Richard D; Lim, Rebecca; Brichta, Alan M

2018-01-01

In the mammalian vestibular periphery, electrical activation of the efferent vestibular system (EVS) has two effects on afferent activity: 1) it increases background afferent discharge and 2) decreases afferent sensitivity to rotational stimuli. Although the cellular mechanisms underlying these two contrasting afferent responses remain obscure, we postulated that the reduction in afferent sensitivity was attributed, in part, to the activation of α9- containing nicotinic acetylcholine (ACh) receptors (α9*nAChRs) and small-conductance potassium channels (SK) in vestibular type II hair cells, as demonstrated in the peripheral vestibular system of other vertebrates. To test this hypothesis, we examined the effects of the predominant EVS neurotransmitter ACh on vestibular type II hair cells from wild-type (wt) and α9-subunit nAChR knockout (α9 -/- ) mice. Immunostaining for choline acetyltransferase revealed there were no obvious gross morphological differences in the peripheral EVS innervation among any of these strains. ACh application onto wt type II hair cells, at resting potentials, produced a fast inward current followed by a slower outward current, resulting in membrane hyperpolarization and decreased membrane resistance. Hyperpolarization and decreased resistance were due to gating of SK channels. Consistent with activation of α9*nAChRs and SK channels, these ACh-sensitive currents were antagonized by the α9*nAChR blocker strychnine and SK blockers apamin and tamapin. Type II hair cells from α9 -/- mice, however, failed to respond to ACh at all. These results confirm the critical importance of α9nAChRs in efferent modulation of mammalian type II vestibular hair cells. Application of exogenous ACh reduces electrical impedance, thereby decreasing type II hair cell sensitivity. NEW & NOTEWORTHY Expression of α9 nicotinic subunit was crucial for fast cholinergic modulation of mammalian vestibular type II hair cells. These findings show a multifaceted efferent mechanism for altering hair cell membrane potential and decreasing membrane resistance that should reduce sensitivity to hair bundle displacements.

Provoked Vestibulodynia: Does Pain Intensity Correlate With Sexual Dysfunction and Dissatisfaction?

PubMed

Aerts, Leen; Bergeron, Sophie; Pukall, Caroline F; Khalifé, Samir

2016-06-01

Provoked vestibulodynia (PVD) is suspected to be the most frequent cause of vulvodynia in premenopausal women. Previous research has been inconclusive as to whether higher vulvovaginal pain ratings are associated with lower sexual function and satisfaction in women with PVD. Whether pain intensity correlates with sexual impairment is an important question given its implications for treatment recommendations. To examine the associations among self-reported and objective pain measurements, sexual function, and sexual satisfaction in a large combined clinical and community sample of premenopausal women diagnosed with PVD. Ninety-eight women with PVD underwent a cotton-swab test, a vestibular friction pain measurement, and a vestibular pressure-pain threshold measurement. In addition to sociodemographics, participants completed measurements of pain, sexual function, and sexual satisfaction. Self-report measurements were the pain numerical rating scale (0-10), the McGill-Melzack Pain Questionnaire, the Female Sexual Function Index, and the Global Measure of Sexual Satisfaction. Objective measurements were pain during a cotton-swab test, pain during a vestibular friction procedure, and the vestibular pressure-pain threshold measurement. Age and relationship duration were significantly correlated with the Female Sexual Function Index total score (r = -0.31, P < .01; and r = -0.22, P < .05, respectively). When controlling for age, intercourse-related pain intensity, pain during the cotton-swab test, pain during vestibular friction, the vestibular pressure-pain threshold, and the McGill-Melzack Pain Questionnaire sensory and affective subscale scores were not significantly associated with sexual function and satisfaction in women with PVD. The findings show that in women with PVD, self-report and objective pain ratings are not associated with sexual function and satisfaction. The results support the biopsychosocial nature of PVD and underscore the importance of a patient-focused multidisciplinary treatment approach for PVD. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Long-term potentiation of synaptic response and intrinsic excitability in neurons of the rat medial vestibular nuclei.

PubMed

Pettorossi, V E; Dieni, C V; Scarduzio, M; Grassi, S

2011-07-28

Using intracellular recordings, we investigated the effects of high frequency stimulation (HFS) of the primary vestibular afferents on the evoked excitatory postsynaptic potential (EPSP) and intrinsic excitability (IE) of type-A and type-B neurons of the medial vestibular nucleus (MVN), in male rat brainstem slices. HFS induces long-term potentiation (LTP) of both EPSP and IE, which may occur in combination or separately. Synaptic LTP is characterized by an increase in the amplitude, slope and decay time constant of EPSP and IE-LTP through enhancements of spontaneous and evoked neuron firing and of input resistance (Rin). Moreover, IE-LTP is associated with a decrease in action potential afterhyperpolarization (AHP) amplitude and an increase in interspike slope steepness (ISS). The more frequent effects of HFS are EPSP-LTP in type-B neurons and IE-LTP in type-A neurons. In addition, the development of EPSP-LTP is fast in type-B neurons but slow in type-A, whereas IE-LTP develops slowly in both types. We have demonstrated that activation of N-methyl-d aspartate receptors (NMDARs) is only required for EPSP-LTP induction, whereas metabotropic glutamate receptors type-1 (mGluR1) are necessary for IE-LTP induction as well as the full development and maintenance of EPSP-LTP. Taken together, these findings demonstrate that brief and intense activation of vestibular afferent input to the MVN neurons may provoke synaptic LTP and/or IE-LTP that, induced in combination or separately, may assure the different selectivity of the MVN neuron response enhancement to the afferent signals. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

Evolution of Gravity Receptors in the Ear

NASA Technical Reports Server (NTRS)

Popper, Arthur N. (Principal Investigator)

1996-01-01

The general status of a grant to investigate the origins and evolution of two hair cell types in the ears of a teleost fish, Astronotus ocellatus (the oscar), is presented. First, it was demonstrated that the cells in the rostral end of the saccule of the , Carassius auratus, are type 1-like, while those at the caudal end are type 2 cells. It was demonstrated that the dichotomy of hair cell types found in the utricle of the oscar is also found in the goldfish. Second, the lateral line system of the oscar was examined using gentamicin sulphate, an ototocix drug that destroys type 1- like hair cells but does not appear to damage type 2 hair cells. It was demonstrated that the hair cells found in neuromasts of lateral line canal organs were totally destroyed within 1 day of treatment, while the hair cells in free neuromasts were undamaged after 12 days of treatment. Third, it was demonstrated that the calyx, the specialized nerve ending, is not unique to amniotes and that it is present at least in the cristae of semicirular canals in goldfish. These results have demonstrated that: (1) there are multiple hair cell types in the vestibular endorgans of the ear of fishes, (2) these hair cell types are very similar to those found in the mammalian vestibular endorgans, (3) the nerve calyx is also present in fishes, and (4) multiple hair cell types and the calyx have evolved far earlier in the course of vertebrate evolution than heretofore thought. Understanding the structure of the vestibular endorgans has important implications for being able to understand how these organs respond to gravistatic, acceleration and acoustic input. The vestibular endorgans of fishes may provide an ideal system in which to analyze functional differences in hair cells. Not only are the two hair cell types similar to those found in mammals, they are located in very discrete regions in each endorgan. Thus, it is relatively easy to gain access to cells of one or the other type. The presence of two cell types in the lateral line have equally significant implications for studies of the vestibular system.

Orientation: Sensory basis; Proceedings of the Conference, New York, N.Y., February 8-10, 1971.

NASA Technical Reports Server (NTRS)

1971-01-01

Topics related to photoreceptors are considered, giving attention to visual pattern recognition and directional orientation in insects, the sensory basis of orientation in amphibians, and the aerial and underwater visual acuity in the California sea lion as a function of luminance. Other subjects explored are in the fields of phonoreceptors, chemoreception, vestibular receptors, and electrical and magnetic sensitivity. Questions of the development and evolution of orientation are also investigated, taking into account field studies of mass emigration and orientation in the spiny lobster and investigations concerning the jumping behavior in the Gobiid fish. Individual items are announced in this issue.

Vestibular rehabilitation outcomes in the elderly with chronic vestibular dysfunction.

PubMed

Bayat, Arash; Pourbakht, Akram; Saki, Nader; Zainun, Zuraida; Nikakhlagh, Soheila; Mirmomeni, Golshan

2012-11-01

Chronic vestibular dysfunction is a frustrating problem in the elderly and can have a tremendous impact on their life, but only a few studies are available. Vestibular rehabilitation therapy (VRT) is an important therapeutic option for the neuro-otologist in treating patients with significant balance deficits. The purpose of this study was to assess the effect of vestibular rehabilitation on dizziness in elderly patients with chronic vestibular dysfunction. A total of 33 patients older than 60 years with chronic vestibular dysfunction were studied. Clinical and objective vestibular tests including videonystagmography (VNG) and dizziness handicap inventory (DHI) were carried out at their first visit, 2 weeks, and 8 weeks post-VRT. The VRT exercises were performed according to Cawthorne and Cooksey protocols. Oculomotor assessments were within normal limits in all patients. Nineteen patients (57.57%) showed abnormal canal paralysis on caloric testing which at follow-up sessions; CP values were decreased remarkably after VRT exercises. We found a significant improvement between pre-VRT and post-VRT total DHI scores (P < 0.001). This improvement was most prominent in functional subscore. Our study demonstrated that VRT is an effective therapeutic method for elderly patients with chronic vestibular dysfunction.

Acute Unilateral Vestibular Failure Does Not Cause Spatial Hemineglect.

PubMed

Conrad, Julian; Habs, Maximilian; Brandt, Thomas; Dieterich, Marianne

2015-01-01

Visuo-spatial neglect and vestibular disorders have common clinical findings and involve the same cortical areas. We questioned (1) whether visuo-spatial hemineglect is not only a disorder of spatial attention but may also reflect a disorder of higher cortical vestibular function and (2) whether a vestibular tone imbalance due to an acute peripheral dysfunction can also cause symptoms of neglect or extinction. Therefore, patients with an acute unilateral peripheral vestibular failure (VF) were tested for symptoms of hemineglect. Twenty-eight patients with acute VF were assessed for signs of vestibular deficits and spatial neglect using clinical measures and various common standardized paper-pencil tests. Neglect severity was evaluated further with the Center of Cancellation method. Pathological neglect test scores were correlated with the degree of vestibular dysfunction determined by the subjective visual vertical and caloric testing. Three patients showed isolated pathological scores in one or the other neglect test, either ipsilesionally or contralesionally to the VF. None of the patients fulfilled the diagnostic criteria of spatial hemineglect or extinction. A vestibular tone imbalance due to unilateral failure of the vestibular endorgan does not cause spatial hemineglect, but evidence indicates it causes mild attentional deficits in both visual hemifields.

Acute Unilateral Vestibular Failure Does Not Cause Spatial Hemineglect

PubMed Central

Conrad, Julian; Habs, Maximilian; Brandt, Thomas; Dieterich, Marianne

2015-01-01

Objectives Visuo-spatial neglect and vestibular disorders have common clinical findings and involve the same cortical areas. We questioned (1) whether visuo-spatial hemineglect is not only a disorder of spatial attention but may also reflect a disorder of higher cortical vestibular function and (2) whether a vestibular tone imbalance due to an acute peripheral dysfunction can also cause symptoms of neglect or extinction. Therefore, patients with an acute unilateral peripheral vestibular failure (VF) were tested for symptoms of hemineglect. Methods Twenty-eight patients with acute VF were assessed for signs of vestibular deficits and spatial neglect using clinical measures and various common standardized paper-pencil tests. Neglect severity was evaluated further with the Center of Cancellation method. Pathological neglect test scores were correlated with the degree of vestibular dysfunction determined by the subjective visual vertical and caloric testing. Results Three patients showed isolated pathological scores in one or the other neglect test, either ipsilesionally or contralesionally to the VF. None of the patients fulfilled the diagnostic criteria of spatial hemineglect or extinction. Conclusions A vestibular tone imbalance due to unilateral failure of the vestibular endorgan does not cause spatial hemineglect, but evidence indicates it causes mild attentional deficits in both visual hemifields. PMID:26247469

[The clinical manifestations and neurophysiological features of long-lasting paroxysmal vertigo:theanalysis of the original observations].

PubMed

Likhachev, S A; Mar'enko, I P

2015-01-01

The objective of the present study was to elucidate specific features of etiology and pathophysiology of recurring chronic vestibular dysfunction. It included 90 patients with this pathology of whom 24 (26.6%) presented with vascular compression of the vestibulocochlear nerve diagnosed by means of high-field MRI. This method revealed the high frequency of positionally-dependent vestibular dysfunction associated with neurovascular interactions. Analysis of the state of vestibular dysfunction during the attack-free periods demonstrated the signs of latent vestibular dysfunction in 20 (83.3%) patients. The results of the study provide additional information on the prevalence of vascular compression of the vestibulocochlear nerve in the patients presenting with recurrent chronic dizziness; moreover, they make it possible to evaluate the state of vestibular function and develop the new diagnostic criteria for vestibular paroxismia.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vignaux, G.; Univ Caen, Caen, F-14000; Chabbert, C.

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, themore » 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.« less

Impact of Diabetic Complications on Balance and Falls: Contribution of the Vestibular System

PubMed Central

Lin, James; Staecker, Hinrich; Whitney, Susan L.; Kluding, Patricia M.

2016-01-01

Diabetes causes many complications, including retinopathy and peripheral neuropathy, which are well understood as contributing to gait instability and falls. A less understood complication of diabetes is the effect on the vestibular system. The vestibular system contributes significantly to balance in static and dynamic conditions by providing spatially orienting information. It is noteworthy that diabetes has been reported to affect vestibular function in both animal and clinical studies. Pathophysiological changes in peripheral and central vestibular structures due to diabetes have been noted. Vestibular dysfunction is associated with impaired balance and a higher risk of falls. As the prevalence of diabetes increases, so does the potential for falls due to diabetic complications. The purpose of this perspective article is to present evidence on the pathophysiology of diabetes-related complications and their influence on balance and falls, with specific attention to emerging evidence of vestibular dysfunction due to diabetes. Understanding this relationship may be useful for screening (by physical therapists) for possible vestibular dysfunction in people with diabetes and for further developing and testing the efficacy of interventions to reduce falls in this population. PMID:26251477

21 CFR 874.1800 - Air or water caloric stimulator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... vestibular function testing of a patient's body balance system. The vestibular stimulation of the...) Classification. Class I (general controls). The device is exempt from the premarket notification procedures in...

Progress Toward Development of a Multichannel Vestibular Prosthesis for Treatment of Bilateral Vestibular Deficiency

PubMed Central

FRIDMAN, GENE Y.; DELLA SANTINA, CHARLES C.

2014-01-01

This article reviews vestibular pathology and the requirements and progress made in the design and construction of a vestibular prosthesis. Bilateral loss of vestibular sensation is disabling. When vestibular hair cells are injured by ototoxic medications or other insults to the labyrinth, the resulting loss of sensory input disrupts vestibulo-ocular reflexes (VORs) and vestibulo-spinal reflexes that normally stabilize the eyes and body. Affected individuals suffer poor vision during head movement, postural instability, chronic disequilibrium, and cognitive distraction. Although most individuals with residual sensation compensate for their loss over time, others fail to do so and have no adequate treatment options. A vestibular prosthesis analogous to cochlear implants but designed to modulate vestibular nerve activity during head movement should improve quality of life for these chronically dizzy individuals. We describe the impact of bilateral loss of vestibular sensation, animal studies supporting feasibility of prosthetic vestibular stimulation, the current status of multichannel vestibular sensory replacement prosthesis development, and challenges to successfully realizing this approach in clinical practice. In bilaterally vestibular-deficient rodents and rhesus monkeys, the Johns Hopkins multichannel vestibular prosthesis (MVP) partially restores the three-dimensional (3D) VOR for head rotations about any axis. Attempts at prosthetic vestibular stimulation of humans have not yet included the 3D eye movement assays necessary to accurately evaluate VOR alignment, but these initial forays have revealed responses that are otherwise comparable to observations in animals. Current efforts now focus on refining electrode design and surgical technique to enhance stimulus selectivity and preserve cochlear function, optimizing stimulus protocols to improve dynamic range and reduce excitation–inhibition asymmetry, and adapting laboratory MVP prototypes into devices appropriate for use in clinical trials. PMID:23044664

Integration of Canal and Otolith Inputs by Central Vestibular Neurons Is Subadditive for Both Active and Passive Self-Motion: Implication for Perception

PubMed Central

Carriot, Jerome; Jamali, Mohsen; Brooks, Jessica X.

2015-01-01

Traditionally, the neural encoding of vestibular information is studied by applying either passive rotations or translations in isolation. However, natural vestibular stimuli are typically more complex. During everyday life, our self-motion is generally not restricted to one dimension, but rather comprises both rotational and translational motion that will simultaneously stimulate receptors in the semicircular canals and otoliths. In addition, natural self-motion is the result of self-generated and externally generated movements. However, to date, it remains unknown how information about rotational and translational components of self-motion is integrated by vestibular pathways during active and/or passive motion. Accordingly, here, we compared the responses of neurons at the first central stage of vestibular processing to rotation, translation, and combined motion. Recordings were made in alert macaques from neurons in the vestibular nuclei involved in postural control and self-motion perception. In response to passive stimulation, neurons did not combine canal and otolith afferent information linearly. Instead, inputs were subadditively integrated with a weighting that was frequency dependent. Although canal inputs were more heavily weighted at low frequencies, the weighting of otolith input increased with frequency. In response to active stimulation, neuronal modulation was significantly attenuated (∼70%) relative to passive stimulation for rotations and translations and even more profoundly attenuated for combined motion due to subadditive input integration. Together, these findings provide insights into neural computations underlying the integration of semicircular canal and otolith inputs required for accurate posture and motor control, as well as perceptual stability, during everyday life. PMID:25716854

Significance of Vestibular Testing on Distinguishing the Nerve of Origin for Vestibular Schwannoma and Predicting the Preservation of Hearing

PubMed Central

He, Yu-Bo; Yu, Chun-Jiang; Ji, Hong-Ming; Qu, Yan-Ming; Chen, Ning

2016-01-01

Background: Determining the nerve of origin for vestibular schwannoma (VS), as a method for predicting hearing prognosis, has not been systematically considered. The vestibular test can be used to investigate the function of the superior vestibular nerve (SVN) and the inferior vestibular nerve (IVN). This study aimed to preoperatively distinguish the nerve of origin for VS patients using the vestibular test, and determine if this correlated with hearing preservation. Methods: A total of 106 patients with unilateral VS were enrolled in this study prospectively. Each patient received a caloric test, vestibular-evoked myogenic potential (VEMP) test, and cochlear nerve function test (hearing) before the operation and 1 week, 3, and 6 months, postoperatively. All patients underwent surgical removal of the VS using the suboccipital approach. During the operation, the nerve of tumor origin (SVN or IVN) was identified by the surgeon. Tumor size was measured by preoperative magnetic resonance imaging. Results: The nerve of tumor origin could not be unequivocally identified in 38 patients (38/106, 35.80%). These patients were not subsequently evaluated. In 26 patients (nine females, seventeen males), tumors arose from the SVN and in 42 patients (18 females, 24 males), tumors arose from the IVN. Comparing with the nerve of origins (SVN and IVN) of tumors, the results of the caloric tests and VEMP tests were significantly different in tumors originating from the SVN and the IVN in our study. Hearing was preserved in 16 of 26 patients (61.54%) with SVN-originating tumors, whereas hearing was preserved in only seven of 42 patients (16.67%) with IVN-originating tumors. Conclusions: Our data suggest that caloric and VEMP tests might help to identify whether VS tumors originate from the SVN or IVN. These tests could also be used to evaluate the residual function of the nerves after surgery. Using this information, we might better predict the preservation of hearing for patients. PMID:26996474

[Diagnosis and treatment of the most frequent vestibular syndromes].

PubMed

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

2005-03-01

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

Effects of vestibular rehabilitation combined with transcranial cerebellar direct current stimulation in patients with chronic dizziness: An exploratory study.

PubMed

Koganemaru, Satoko; Goto, Fumiyuki; Arai, Miki; Toshikuni, Keitaro; Hosoya, Makoto; Wakabayashi, Takeshi; Yamamoto, Nobuko; Minami, Shujiro; Ikeda, Satoshi; Ikoma, Katsunori; Mima, Tatsuya

Vestibular rehabilitation is useful to alleviate chronic dizziness in patients with vestibular dysfunction. It aims to induce neuronal plasticity in the central nervous system (especially in the cerebellum) to promote vestibular compensation. Transcranial cerebellar direct current stimulation (tcDCS) reportedly enhances cerebellar function. We investigated whether vestibular rehabilitation partially combined with tcDCS is superior to the use of rehabilitation alone for the alleviation of dizziness. Patients with chronic dizziness due to vestibular dysfunction received rehabilitation concurrently with either 20-min tcDCS or sham stimulation for 5 days. Pre- and post-intervention (at 1 month) dizziness handicap inventory (DHI) scores and psychometric and motor parameters were compared. Sixteen patients completed the study. DHI scores in the tcDCS group showed significant improvement over those in the sham group (Mann-Whitney U test, p = 0.033). Vestibular rehabilitation partially combined with tcDCS appears to be a promising approach. Copyright © 2017 Elsevier Inc. All rights reserved.

Changes in the Vestibular System with Age: An Abstracted Bibliography,

DTIC Science & Technology

1981-04-30

group." COMMENT: Similar to other articles in this series, showing significant loss of afferents (and possibly efferents) in the vestibular nerve. k...marked dependence of postural stability on vision . In them, the disturbing optokinetic stimulus leads to a marked ipsilateral postural deviation or...SUBJECTS (Number-age): N/A EXPERIMENTAL PROCEDURES: Review FINDINGS: 1. No mention of vestibular functioning. 2. Review sections on vision , audition

Clinical benefits to vestibular rehabilitation in multiple sclerosis. Report of 4 cases.

PubMed

Zeigelboim, Bianca; Liberalesso, Paulo; Jurkiewicz, Ari; Klagenberg, Karlin

2010-01-01

Balance difficulties are common among multiple sclerosis patients. To evaluate the effectiveness of the Cawthorne and Cooksey protocol of vestibular rehabilitation (VR) exercises in reducing the physical, functional and emotional impact of multiple sclerosis among individuals who complained of vertigo. Four patients with remittent-recurrent multiple sclerosis underwent an interview, otorhinolaryngological and vestibular evaluation, VR exercises and the Dizziness Handicap Inventory pre- and post-intervention. There was significant improvement in the physical, functional and emotional aspects of the DHI after the completion of the VR. The VR exercises appeared useful in reducing subjective complaints of the study participants.

PREHAB vs. REHAB - presurgical treatment in vestibular schwannoma surgery enhances recovery of postural control better than postoperative rehabilitation: Retrospective case series.

PubMed

Tjernström, Fredrik; Fransson, Per-Anders; Kahlon, Babar; Karlberg, Mikael; Lindberg, Sven; Siesjö, Peter; Magnusson, Måns

2018-01-01

To evaluate post-surgical postural stability when treating patients with remaining vestibular function with intratympanic gentamicin (PREHAB) prior to schwannoma surgery. 44 consecutive patients with some form remaining vestibular function scheduled for vestibular schwannoma surgery. 20 were medically deafferented with intratympanic gentamicin before surgery and 24 were not. Both groups were of the same age, had the same tumor size, same type of surgery, and same perioperative sensory rehabilitation (training exercises), and no surgical complications. Postural stability measured as energy expenditure while standing on a force platform during vibratory stimulation of the calf muscles, performed prior to surgery (or gentamicin treatment) and 6 months after surgery. Patients pretreated with gentamicin had significantly better postural stability at the time for follow-up (p < 0.05) and displayed a better adaptive capacity when faced with a postural challenge (p < 0.01). They were also able to use vision more efficiently to control their stability (p < 0.05). By separating the sensory loss (through intratympanic gentamicin, that ablates the remaining vestibular function) from the intracranial surgical trauma, the postural control system benefited from a better short-term (adaptation) and long-term (habituation) recovery, when experiencing a postural challenge or resolving a sensory conflict. The benefits could be attributed to; active and continuous motor learning as the vestibular function slowly attenuates; no concomitant central nervous dysfunction due to effects from neurosurgery, thus allowing time for a separate unimpeded recovery process with more limited challenges and objectives; and the initiation and certain progression of sensory reweighting processes allowed prior to surgery. In contrast, worse compensation could be due to; immobilization from nausea after surgery, harmful amount of stress and cognitive dysfunction from the combination of surgical and sensory trauma and an abrupt vestibular deafferentation and its consequences on sensory reweighting.

Changes in resting-state fMRI in vestibular neuritis.

PubMed

Helmchen, Christoph; Ye, Zheng; Sprenger, Andreas; Münte, Thomas F

2014-11-01

Vestibular neuritis (VN) is a sudden peripheral unilateral vestibular failure with often persistent head movement-related dizziness and unsteadiness. Compensation of asymmetrical activity in the primary peripheral vestibular afferents is accomplished by restoration of impaired brainstem vestibulo-ocular and vestibulo-spinal reflexes, but presumably also by changing cortical vestibular tone imbalance subserving, e.g., spatial perception and orientation. The aim of this study was to elucidate (i) whether there are changes of cerebral resting-state networks with respect to functional interregional connectivity (resting-state activity) in VN patients and (ii) whether these are related to neurophysiological, perceptual and functional parameters of vestibular-induced disability. Using independent component analysis (ICA), we compared resting-state networks between 20 patients with unilateral VN and 20 age- and gender-matched healthy control subjects. Patients were examined in the acute VN stage and after 3 months. A neural network (component 50) comprising the parietal lobe, medial aspect of the superior parietal lobule, posterior cingulate cortex, middle frontal gyrus, middle temporal gyrus, parahippocampal gyrus, anterior cingulate cortex, insular cortex, caudate nucleus, thalamus and midbrain was modulated between acute VN patients and healthy controls and in patients over time. Within this network, acute VN patients showed decreased resting-state activity (ICA) in the contralateral intraparietal sulcus (IPS), in close vicinity to the supramarginal gyrus (SMG), which increased after 3 months. Resting-state activity in IPS tended to increase over 3 months in VN patients who improved with respect to functional parameters of vestibular-induced disability (VADL). Resting-state activity in the IPS was not related to perceptual (subjective visual vertical) or neurophysiological parameters of vestibular-induced disability (e.g., gain of vestibulo-ocular reflex, caloric responsiveness, postural sway). VN leads to a change in resting-state activity of the contralateral IPS adjacent to the SMG, which reverses during vestibular compensation over 3 months. The ventral intraparietal area in the IPS contains multimodal regions with directionally selective responses to vestibular stimuli making them suitable for participating in spatial orientation and multisensory integration. The clinical importance is indicated by the fact that the increase in resting-state activity tended to be larger in those patients with only little disability at the follow-up examination. This may indicate powerful restitution-related or compensatory cortical changes in resting-state activity.

Translabyrinthine surgery for disabling vertigo in vestibular schwannoma patients.

PubMed

Godefroy, W P; Hastan, D; van der Mey, A G L

2007-06-01

To determine the impact of translabyrinthine surgery on the quality of life in vestibular schwannoma patients with rotatory vertigo. Prospective study in 18 vestibular schwannoma patients. The study was conducted in a multispecialty tertiary care clinic. All 18 patients had a unilateral intracanalicular vestibular schwannoma, without serviceable hearing in the affected ear and severely handicapped by attacks of rotatory vertigo and constant dizziness. Despite an initial conservative treatment, extensive vestibular rehabilitation exercises, translabyrinthine surgery was performed because of the disabling character of the vertigo, which considerably continued to affect the patients' quality of life. Preoperative and postoperative quality of life using the Short Form 36 Health Survey (Short Form-36) scores and Dizziness Handicap Inventory (DHI) scores. A total of 17 patients (94%) completed the questionnaire preoperatively and 3 and 12 months postoperatively. All Short Form-36 scales of the studied patients scored significantly lower when compared with the healthy Dutch control sample (P < 0.05). There was a significant improvement of DHI total scores and Short Form-36 scales on physical and social functioning, role-physical functioning, role-emotional functioning, mental health and general health at 12 months after surgery when compared with preoperative scores (P < 0.05). Vestibular schwannoma patients with disabling vertigo, experience significant reduced quality of life when compared with a healthy Dutch population. Translabyrinthine tumour removal significantly improved the patients' quality of life. Surgical treatment should be considered in patients with small- or medium-sized tumours and persisting disabling vertigo resulting in a poor quality of life.

Vestibular signals in primate cortex for self-motion perception.

PubMed

Gu, Yong

2018-04-21

The vestibular peripheral organs in our inner ears detect transient motion of the head in everyday life. This information is sent to the central nervous system for automatic processes such as vestibulo-ocular reflexes, balance and postural control, and higher cognitive functions including perception of self-motion and spatial orientation. Recent neurophysiological studies have discovered a prominent vestibular network in the primate cerebral cortex. Many of the areas involved are multisensory: their neurons are modulated by both vestibular signals and visual optic flow, potentially facilitating more robust heading estimation through cue integration. Combining psychophysics, computation, physiological recording and causal manipulation techniques, recent work has addressed both the encoding and decoding of vestibular signals for self-motion perception. Copyright © 2018. Published by Elsevier Ltd.

Role of vestibular information in initiation of rapid postural responses

NASA Technical Reports Server (NTRS)

Runge, C. F.; Shupert, C. L.; Horak, F. B.; Zajac, F. E.; Peterson, B. W. (Principal Investigator)

1998-01-01

Patients with bilateral vestibular loss have difficulty maintaining balance without stepping when standing in tandem, on compliant surfaces, across narrow beams, or on one foot, especially with eyes closed. Normal individuals (with no sensory impairment) maintain balance in these tasks by employing quick, active hip rotation (a "hip strategy"). The absence of a hip strategy in vestibular patients responding to translations of a short support surface has previously been taken as evidence that the use of hip strategy requires an intact vestibular system. However, many tasks requiring hip strategy alter one or a combination of important system characteristics, such as initial state of the body (tandem stance), dynamics (compliant surfaces), or biomechanical limits of stability (narrow beams). Therefore, the balance deficit in these tasks may result from a failure to account for these support surface alterations when planning and executing sensorimotor responses. In this study, we tested the hypothesis that vestibular information is critical to trigger a hip strategy even on an unaltered support surface, which imposes no changes on the system characteristics. We recorded the postural responses of vestibular patients and control subjects with eyes closed to rearward support surface translations of varying velocity, in erect stance on a firm, flat surface. Subjects were instructed to maintain balance without stepping, if possible. Faster translation velocities (25 cm/s or more) produced a consistent pattern of early hip torque (first 400 ms) in control subjects (i.e., a hip strategy). Most of the patients with bilateral vestibular loss responded to the same translation velocities with similar torques. Contrary to our hypothesis, we conclude that vestibular function is not necessary to trigger a hip strategy. We postulate, therefore, that the balance deficit previously observed in vestibular patients during postural tasks that elicit a hip strategy may have been due to the sensorimotor consequences of the system alterations imposed by the postural tasks used in those studies. Preliminary results from two younger patients who lost vestibular function as infants indicate that age, duration of vestibular loss, and/or the timing of the loss may also be factors that can influence the use of hip strategy as a rapid postural response.

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

PubMed

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

2014-07-01

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.

Cholinergic agonists increase intracellular calcium concentration in guinea pig vestibular hair cells.

PubMed

Han, W; Zhang, S; Han, D; Jiang, S; Yang, W

2001-07-01

To better understand the cholinergic receptors in vestibular hair cells (VHC) and their subtypes, and to investigate the effects of cholinergic agonists on intracellular calcium concentration ([Ca2+]i) in guinea pig VHCs. VHCs were isolated from guinea pig crista ampullaris by enzymatic and mechanical methods. The effect of cholinergic agonists on [Ca2+]i was examined using laser scanning confocal microscopy and the Ca2+ sensitive dye Fluo-3. The results showed that the addition of acetylcholine (ACh) and carbachol (CCh), muscamic and nicotinic agonists, induced [Ca2+]i increases in all the VHCs, whereas acetylcholine bromide (ACh-Br), a nicotinic agonist, induced the [Ca2+]i increase in only a small percentage of VHCs. The ACh or CCh-induced Ca2+ response could be partially suppressed by atropine. In the presence of 0.1 mmol/L atropine, the amplitudes of ACh or CCh-induced [Ca2+]i responses became significantly smaller than those in atropine free medium (P < 0.01). The results suggest the existence of cholinergic receptors in guinea pig VHCs. It is the muscamic agonists rather than nicontic receptors that dominate [Ca2+]i variation. Atropine can suppress muscamic agonist-induced Ca2+ responses.

Vestibular neurolabyrinthitis: a follow-up study with cervical and ocular vestibular evoked myogenic potentials and the video head impulse test.

PubMed

Magliulo, Giuseppe; Gagliardi, Silvia; Ciniglio Appiani, Mario; Iannella, Giannicola; Re, Massimo

2014-03-01

The aim of this study was to evaluate prospectively, in a group of patients affected by vestibular neurolabyrinthitis (VN), a diagnostic protocol including cervical vestibular evoked myogenic potentials (C-VEMPs), ocular vestibular evoked myogenic potentials (O-VEMPs), and the video head impulse test (vHIT). The diagnosis of VN was based on the patient's clinical history, an absence of associated auditory or neurologic symptoms, and a neuro-otological examination with an evaluation of lateral semicircular canal function by use of the Fitzgerald-Hallpike caloric vestibular test and the ice test. In our series, 55% of the cases were superior and inferior VN, 40% were superior VN, and 5% were inferior VN. These cases, however, comprised different degrees of vestibular involvement, as the individual vestibular end organs have different prognoses. Four patients had only deficits of the horizontal and superior semicircular canals or their ampullary nerves. The implementation of C-VEMPs, O-VEMPs, and the vHIT in a vestibular diagnostic protocol has made it possible to observe patients with ampullary VN in a way that has not been feasible with other types of vestibular examinations. The age of the patient seems to have some impact on recovery from VN. When recovery occurs in the utricular and saccular nerves first and in the ampullary nerves subsequently, it may be reasonable to expect a more favorable outcome.

The Neural Correlates of Chronic Symptoms of Vertigo Proneness in Humans

PubMed Central

Alsalman, Ola; Ost, Jan; Vanspauwen, Robby; Blaivie, Catherine; De Ridder, Dirk; Vanneste, Sven

2016-01-01

Vestibular signals are of significant importance for variable functions including gaze stabilization, spatial perception, navigation, cognition, and bodily self-consciousness. The vestibular network governs functions that might be impaired in patients affected with vestibular dysfunction. It is currently unclear how different brain regions/networks process vestibular information and integrate the information into a unified spatial percept related to somatosensory awareness and whether people with recurrent balance complaints have a neural signature as a trait affecting their development of chronic symptoms of vertigo. Pivotal evidence points to a vestibular-related brain network in humans that is widely distributed in nature. By using resting state source localized electroencephalography in non-vertiginous state, electrophysiological changes in activity and functional connectivity of 23 patients with balance complaints where chronic symptoms of vertigo and dizziness are among the most common reported complaints are analyzed and compared to healthy subjects. The analyses showed increased alpha2 activity within the posterior cingulate cortex and the precuneues/cuneus and reduced beta3 and gamma activity within the pregenual and subgenual anterior cingulate cortex for the subjects with balance complaints. These electrophysiological variations were correlated with reported chronic symptoms of vertigo intensity. A region of interest analysis found reduced functional connectivity for gamma activity within the vestibular cortex, precuneus, frontal eye field, intra-parietal sulcus, orbitofrontal cortex, and the dorsal anterior cingulate cortex. In addition, there was a positive correlation between chronic symptoms of vertigo intensity and increased alpha-gamma nesting in the left frontal eye field. When compared to healthy subjects, there is evidence of electrophysiological changes in the brain of patients with balance complaints even outside chronic symptoms of vertigo episodes. This suggests that these patients have a neural signature or trait that makes them prone to developing chronic balance problems. PMID:27089185

The Neural Correlates of Chronic Symptoms of Vertigo Proneness in Humans.

PubMed

Alsalman, Ola; Ost, Jan; Vanspauwen, Robby; Blaivie, Catherine; De Ridder, Dirk; Vanneste, Sven

2016-01-01

Vestibular signals are of significant importance for variable functions including gaze stabilization, spatial perception, navigation, cognition, and bodily self-consciousness. The vestibular network governs functions that might be impaired in patients affected with vestibular dysfunction. It is currently unclear how different brain regions/networks process vestibular information and integrate the information into a unified spatial percept related to somatosensory awareness and whether people with recurrent balance complaints have a neural signature as a trait affecting their development of chronic symptoms of vertigo. Pivotal evidence points to a vestibular-related brain network in humans that is widely distributed in nature. By using resting state source localized electroencephalography in non-vertiginous state, electrophysiological changes in activity and functional connectivity of 23 patients with balance complaints where chronic symptoms of vertigo and dizziness are among the most common reported complaints are analyzed and compared to healthy subjects. The analyses showed increased alpha2 activity within the posterior cingulate cortex and the precuneues/cuneus and reduced beta3 and gamma activity within the pregenual and subgenual anterior cingulate cortex for the subjects with balance complaints. These electrophysiological variations were correlated with reported chronic symptoms of vertigo intensity. A region of interest analysis found reduced functional connectivity for gamma activity within the vestibular cortex, precuneus, frontal eye field, intra-parietal sulcus, orbitofrontal cortex, and the dorsal anterior cingulate cortex. In addition, there was a positive correlation between chronic symptoms of vertigo intensity and increased alpha-gamma nesting in the left frontal eye field. When compared to healthy subjects, there is evidence of electrophysiological changes in the brain of patients with balance complaints even outside chronic symptoms of vertigo episodes. This suggests that these patients have a neural signature or trait that makes them prone to developing chronic balance problems.

The lesion site of vestibular dysfunction in Ramsay Hunt syndrome: a study by click and galvanic VEMP.

PubMed

Ozeki, Hidenori; Iwasaki, Shinichi; Ushio, Munetaka; Takeuchi, Naonobu; Murofushi, Toshihisa

2006-01-01

Ramsay Hunt syndrome (RHS) is characterized by vestibulocochlear dysfunction in addition to facial paralysis and auricular vesicles. The present study investigated the lesion site of vestibular dysfunction in a group of 10 RHS patients. Caloric testing, vestibular evoked myogenic potentials by click sound (cVEMP) and by galvanic stimulation (gVEMP) were used to assess the function of the lateral semicircular canal, saccule, and their afferents. The results of caloric testing (all 10 cases showed canal paresis) mean the existence of lesion sites in lateral semicircular canal and/or superior vestibular nerve (SVN). Abnormal cVEMPs in 7 patients mean the existence of lesions in saccule and/or inferior vestibular nerve (IVN). Four of the 6 patients with absent cVEMP also underwent gVEMP. The results of gVEMP (2 absent and 2 normal) mean that the former 2 have lesions of the vestibular nerve, and the latter 2 have only saccular lesions concerning the pathway of VEMPs. Thus, our study suggested that lesion sites of vestibular symptoms in RHS could be in the vestibular nerve and/or labyrinth, and in SVN and/or IVN. In other words, in the light of vestibular symptoms, there is the diversity of lesion sites.

Cell Death, Neuronal Plasticity and Functional Loading in the Development of the Central Nervous System

NASA Technical Reports Server (NTRS)

Keefe, J. R.

1985-01-01

Research on the precise timing and regulation of neuron production and maturation in the vestibular and visual systems of Wistar rats and several inbred strains of mice (C57B16 and Pallid mutant) concentrated upon establishing a timing baseline for mitotic development of the neurons of the vestibular nuclei and the peripheral vestibular sensory structures (maculae, cristae). This involved studies of the timing and site of neuronal cell birth and preliminary studies of neuronal cell death in both central and peripheral elements of the mammalian vestibular system. Studies on neuronal generation and maturation in the retina were recently added to provide a mechanism for more properly defining the in utero' developmental age of the individual fetal subject and to closely monitor potential transplacental effects of environmentally stressed maternal systems. Information is given on current efforts concentrating upon the (1) perinatal period of development (E18 thru P14) and (2) the role of cell death in response to variation in the functional loading of the vestibular and proprioreceptive systems in developing mammalian organisms.

Characterizing human vestibular sensory epithelia for experimental studies: new hair bundles on old tissue and implications for therapeutic interventions in ageing

PubMed Central

Taylor, Ruth R.; Jagger, Daniel J.; Saeed, Shakeel R.; Axon, Patrick; Donnelly, Neil; Tysome, James; Moffatt, David; Irving, Richard; Monksfield, Peter; Coulson, Chris; Freeman, Simon R.; Lloyd, Simon K.; Forge, Andrew

2015-01-01

Balance disequilibrium is a significant contributor to falls in the elderly. The most common cause of balance dysfunction is loss of sensory cells from the vestibular sensory epithelia of the inner ear. However, inaccessibility of inner ear tissue in humans severely restricts possibilities for experimental manipulation to develop therapies to ameliorate this loss. We provide a structural and functional analysis of human vestibular sensory epithelia harvested at trans-labyrinthine surgery. We demonstrate the viability of the tissue and labeling with specific markers of hair cell function and of ion homeostasis in the epithelium. Samples obtained from the oldest patients revealed a significant loss of hair cells across the tissue surface, but we found immature hair bundles present in epithelia harvested from patients >60 years of age. These results suggest that the environment of the human vestibular sensory epithelium could be responsive to stimulation of developmental pathways to enhance hair cell regeneration, as has been demonstrated successfully in the vestibular organs of adult mice. PMID:25818177

Vestibular signals in macaque extrastriate visual cortex are functionally appropriate for heading perception

PubMed Central

Liu, Sheng; Angelaki, Dora E.

2009-01-01

Visual and vestibular signals converge onto the dorsal medial superior temporal area (MSTd) of the macaque extrastriate visual cortex, which is thought to be involved in multisensory heading perception for spatial navigation. Peripheral otolith information, however, is ambiguous and cannot distinguish linear accelerations experienced during self-motion from those due to changes in spatial orientation relative to gravity. Here we show that, unlike peripheral vestibular sensors but similar to lobules 9 and 10 of the cerebellar vermis (nodulus and uvula), MSTd neurons respond selectively to heading and not to changes in orientation relative to gravity. In support of a role in heading perception, MSTd vestibular responses are also dominated by velocity-like temporal dynamics, which might optimize sensory integration with visual motion information. Unlike the cerebellar vermis, however, MSTd neurons also carry a spatial orientation-independent rotation signal from the semicircular canals, which could be useful in compensating for the effects of head rotation on the processing of optic flow. These findings show that vestibular signals in MSTd are appropriately processed to support a functional role in multisensory heading perception. PMID:19605631

Characterizing human vestibular sensory epithelia for experimental studies: new hair bundles on old tissue and implications for therapeutic interventions in ageing.

PubMed

Taylor, Ruth R; Jagger, Daniel J; Saeed, Shakeel R; Axon, Patrick; Donnelly, Neil; Tysome, James; Moffatt, David; Irving, Richard; Monksfield, Peter; Coulson, Chris; Freeman, Simon R; Lloyd, Simon K; Forge, Andrew

2015-06-01

Balance disequilibrium is a significant contributor to falls in the elderly. The most common cause of balance dysfunction is loss of sensory cells from the vestibular sensory epithelia of the inner ear. However, inaccessibility of inner ear tissue in humans severely restricts possibilities for experimental manipulation to develop therapies to ameliorate this loss. We provide a structural and functional analysis of human vestibular sensory epithelia harvested at trans-labyrinthine surgery. We demonstrate the viability of the tissue and labeling with specific markers of hair cell function and of ion homeostasis in the epithelium. Samples obtained from the oldest patients revealed a significant loss of hair cells across the tissue surface, but we found immature hair bundles present in epithelia harvested from patients >60 years of age. These results suggest that the environment of the human vestibular sensory epithelium could be responsive to stimulation of developmental pathways to enhance hair cell regeneration, as has been demonstrated successfully in the vestibular organs of adult mice. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Complex vestibular macular anatomical relationships need a synthetic approach

NASA Technical Reports Server (NTRS)

Ross, M. D.

2001-01-01

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.

Vestibular involvement in adults with HIV/AIDS.

PubMed

Heinze, Barbara M; Vinck, Bart M; Hofmeyr, Louis M; Swanepoel, De Wet

2014-04-01

HIV/AIDS is responsible for widespread clinical manifestations involving the head, and neck. The prevalence and nature of vestibular involvement is still largely unknown. This study, aimed to describe and compare the occurrence and nature of vestibular involvement among a group of, adults infected with HIV compared to a control group. It also aimed to compare the vestibular function, of symptomatic and asymptomatic HIV positive adults who receive antiretroviral (ARV) therapies to, subjects not receiving ARV. A cross-sectional study was conducted on 53 adults (29 male, 24 female, aged 23-49 years, mean=38.5, SD=4.4) infected with HIV, compared to a control group of 38 HIV negative adults (18, male, 20 female, aged 20-49 years, mean=36.9, SD=8.2). A structured interview probed the subjective, perception of vestibular symptoms. Medical records were reviewed for CD4+ cell counts and the use of, ARV medication. An otologic assessment and a comprehensive vestibular assessment (bedside, assessments, vestibular evoked myogenic potentials, ocular motor and positional tests and bithermal, caloric irrigation) were conducted. Vestibular involvement occurred in 79.2% of subjects with HIV in all categories of disease, progression, compared to 18.4% in those without HIV. Vestibular involvement increased from 18.9% in CDC category 1 to 30.2% in category 2. Vestibular involvement was 30.1% in category 3. There were, vestibular involvement in 35.9% of symptomatic HIV positive subjects, and 41.5% in asymptomatic, HIV positive subjects. There was no significant difference in the occurrence of vestibular involvement, in subjects receiving ARV therapies compared to those not receiving ARV therapies (p=.914; chi-square, test). The odds ratio indicates that individuals with HIV have a 16.61 times higher risk of developing, vestibular involvement during their lifetime of living with the disease and that it may occur despite, being asymptomatic. Vestibular involvement was significantly more common in subjects with HIV. Primary health care providers could screen HIV positive patients to ascertain if there are symptoms of vestibular involvement. If there are any, then they may consider further vestibular assessments and subsequent vestibular rehabilitation therapy. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Vertigo with sudden hearing loss: audio-vestibular characteristics.

PubMed

Pogson, Jacob M; Taylor, Rachael L; Young, Allison S; McGarvie, Leigh A; Flanagan, Sean; Halmagyi, G Michael; Welgampola, Miriam S

2016-10-01

Acute vertigo with sudden sensorineural hearing loss (SSNHL) is a rare clinical emergency. Here, we report the audio-vestibular test profiles of 27 subjects who presented with these symptoms. The vestibular test battery consisted of a three-dimensional video head impulse test (vHIT) of semicircular canal function and recording ocular and cervical vestibular-evoked myogenic potentials (oVEMP, cVEMP) to test otolith dysfunction. Unlike vestibular neuritis, where the horizontal and anterior canals with utricular function are more frequently impaired, 74 % of subjects with vertigo and SSNHL demonstrated impairment of the posterior canal gain (0.45 ± 0.20). Only 41 % showed impairment of the horizontal canal gains (0.78 ± 0.27) and 30 % of the anterior canal gains (0.79 ± 0.26), while 38 % of oVEMPs [asymmetry ratio (AR) = 41.0 ± 41.3 %] and 33 % of cVEMPs (AR = 47.3 ± 41.2 %) were significantly asymmetrical. Twenty-three subjects were diagnosed with labyrinthitis/labyrinthine infarction in the absence of evidence for an underlying pathology. Four subjects had a definitive diagnosis [Ramsay Hunt Syndrome, vestibular schwannoma, anterior inferior cerebellar artery (AICA) infarction, and traction injury]. Ischemia involving the common-cochlear or vestibulo-cochlear branches of the labyrinthine artery could be the simplest explanation for vertigo with SSNHL. Audio-vestibular tests did not provide easy separation between ischaemic and non-ischaemic causes of vertigo with SSNHL.

Posture, head stability, and orientation recovery during vestibular regeneration in pigeons.

PubMed

Dickman, J David; Lim, Insook

2004-09-01

Compensatory behavior such as oculomotor, gaze, and postural responses that occur during movement largely depend upon a functioning vestibular system. In the present study, the initial loss and subsequent recovery of postural and head stability in pigeons undergoing vestibular regeneration were examined. Adult pigeons were trained to manipulate a straight run chamber to peck an illuminated key for fluid reward. Six behavioral measures assessing performance, posture, and head stability were quantified. These included run latency, steps (walking), path negotiation (lane changes), gaze saccades, head bobs, and head shakes. Once normative values were obtained for four birds, complete lesion of all receptor cells and denervation of the epithelia in the vestibular endorgans were produced using a single intralabyrinthine application of streptomycin sulfate. Each bird was then tested at specific times during regeneration and the same behavioral measures examined. At 7 days post-streptomycin treatment (PST), all birds exhibited severe postural and head instability, with tremors, head shakes, staggering, and circling predominating. No normal trial runs, walking, gaze saccades, or head bobs were present. Many of these dysfunctions persisted through 3-4 weeks PST. Gradually, tremor and head shakes diminished and were replaced with an increasing number of normal head bobs during steps and gaze saccades. Beginning at 4 weeks PST, but largely inaccurate, was the observed initiation of directed steps, less staggering, and some successful path negotiation. As regeneration progressed, spatial orientation and navigation ability increased and, by 49 days PST, most trials were successful. By 70 days PST, all birds had recovered to pretreatment levels. Thus, it was observed that ataxia must subside, coincident with normalized head and postural stability prior to the recovery of spatial orientation and path navigation recovery. Parallels in recovery were drawn to hair cell regeneration and afferent responsiveness, as inferred from present results and those in other investigations.

Decline in semicircular canal and otolith function with age

PubMed Central

Agrawal, Yuri; Zuniga, M. Geraldine; Davalos-Bichara, Marcela; Schubert, Michael C.; Walston, Jeremy D.; Hughes, Jennifer; Carey, John P.

2012-01-01

Objective To characterize the physiologic nature of the vestibular dysfunction that occurs with the normative aging process. Study design Cross-sectional study. Setting Tertiary care academic medical center. Patients Fifty individuals age 70 and above. Interventions Head thrust dynamic visual acuity testing (htDVA) and cervical and ocular vestibular-evoked myogenic potential (VEMP) testing. Main Outcome Measures Semicircular canal function measured by htDVA in each of the three semicircular canal planes, and saccular and utricular function measured by cVEMP and oVEMP testing, respectively. Results We observed significant declines in semicircular canal function in each of the canal planes as well as otolith function associated with aging. We found that individuals with impaired horizontal and superior semicircular canal function were likely to also have concomitant deficits in utricular but not saccular function. Overall, we noted that the prevalence of semicircular canal dysfunction was highest followed by saccular then utricular impairment, although we did observe individuals with isolated otolith deficits. Conclusions These data suggest an overall decline in semicircular canal as well as otolith function associated with aging, although the magnitude of impairment was greater for the semicircular canals than the otoliths in this elderly population. A better understanding of the specific vestibular deficits that occur with aging can inform the development of rational screening, vestibular rehabilitation and fall risk reduction strategies in older individuals. PMID:22699991

Bilateral Vestibular Dysfunction Associated With Chronic Exposure to Military Jet Propellant Type-Eight Jet Fuel

PubMed Central

Fife, Terry D.; Robb, Michael J. A.; Steenerson, Kristen K.; Saha, Kamala C.

2018-01-01

We describe three patients diagnosed with bilateral vestibular dysfunction associated with the jet propellant type-eight (JP-8) fuel exposure. Chronic exposure to aromatic and aliphatic hydrocarbons, which are the main constituents of JP-8 military aircraft jet fuel, occurred over 3–5 years’ duration while working on or near the flight line. Exposure to toxic hydrocarbons was substantiated by the presence of JP-8 metabolite n-hexane in the blood of one of the cases. The presenting symptoms were dizziness, headache, fatigue, and imbalance. Rotational chair testing confirmed bilateral vestibular dysfunction in all the three patients. Vestibular function improved over time once the exposure was removed. Bilateral vestibular dysfunction has been associated with hydrocarbon exposure in humans, but only recently has emphasis been placed specifically on the detrimental effects of JP-8 jet fuel and its numerous hydrocarbon constituents. Data are limited on the mechanism of JP-8-induced vestibular dysfunction or ototoxicity. Early recognition of JP-8 toxicity risk, cessation of exposure, and customized vestibular therapy offer the best chance for improved balance. Bilateral vestibular impairment is under-recognized in those chronically exposed to all forms of jet fuel. PMID:29867750

Bilateral Vestibular Dysfunction Associated With Chronic Exposure to Military Jet Propellant Type-Eight Jet Fuel.

PubMed

Fife, Terry D; Robb, Michael J A; Steenerson, Kristen K; Saha, Kamala C

2018-01-01

We describe three patients diagnosed with bilateral vestibular dysfunction associated with the jet propellant type-eight (JP-8) fuel exposure. Chronic exposure to aromatic and aliphatic hydrocarbons, which are the main constituents of JP-8 military aircraft jet fuel, occurred over 3-5 years' duration while working on or near the flight line. Exposure to toxic hydrocarbons was substantiated by the presence of JP-8 metabolite n -hexane in the blood of one of the cases. The presenting symptoms were dizziness, headache, fatigue, and imbalance. Rotational chair testing confirmed bilateral vestibular dysfunction in all the three patients. Vestibular function improved over time once the exposure was removed. Bilateral vestibular dysfunction has been associated with hydrocarbon exposure in humans, but only recently has emphasis been placed specifically on the detrimental effects of JP-8 jet fuel and its numerous hydrocarbon constituents. Data are limited on the mechanism of JP-8-induced vestibular dysfunction or ototoxicity. Early recognition of JP-8 toxicity risk, cessation of exposure, and customized vestibular therapy offer the best chance for improved balance. Bilateral vestibular impairment is under-recognized in those chronically exposed to all forms of jet fuel.

Correlation between afferent rearrangements and behavioral deficits after local excitotoxic insult in the mammalian vestibule: a rat model of vertigo symptoms.

PubMed

Gaboyard-Niay, Sophie; Travo, Cécile; Saleur, Aurélie; Broussy, Audrey; Brugeaud, Aurore; Chabbert, Christian

2016-10-01

Damage to inner ear afferent terminals is believed to result in many auditory and vestibular dysfunctions. The sequence of afferent injuries and repair, as well as their correlation with vertigo symptoms, remains poorly documented. In particular, information on the changes that take place at the primary vestibular endings during the first hours following a selective insult is lacking. In the present study, we combined histological analysis with behavioral assessments of vestibular function in a rat model of unilateral vestibular excitotoxic insult. Excitotoxicity resulted in an immediate but transient alteration of the balance function that was resolved within a week. Concomitantly, vestibular primary afferents underwent a sequence of structural changes followed by spontaneous repair. Within the first two hours after the insult, a first phase of pronounced vestibular dysfunction coincided with extensive swelling of afferent terminals. In the next 24 h, a second phase of significant but incomplete reduction of the vestibular dysfunction was accompanied by a resorption of swollen terminals and fiber retraction. Eventually, within 1 week, a third phase of complete balance restoration occurred. The slow and progressive withdrawal of the balance dysfunction correlated with full reconstitution of nerve terminals. Competitive re-innervation by afferent and efferent terminals that mimicked developmental synaptogenesis resulted in full re-afferentation of the sensory epithelia. By deciphering the sequence of structural alterations that occur in the vestibule during selective excitotoxic impairment, this study offers new understanding of how a vestibular insult develops in the vestibule and how it governs the heterogeneity of vertigo symptoms. © 2016. Published by The Company of Biologists Ltd.

Responses of Caudal Vestibular Nucleus Neurons of Conscious Cats to Rotations in Vertical Planes, Before and After a Bilateral Vestibular Neurectomy

PubMed Central

Miller, D. M.; Cotter, L. A.; Gandhi, N. J.; Schor, R. H.; Cass, S. P.; Huff, N. O.; Raj, S. G.; Shulman, J. A; Yates, B. J.

2008-01-01

Although many previous experiments have considered the responses of vestibular nucleus neurons to rotations and translations of the head, little data are available regarding cells in the caudalmost portions of the vestibular nuclei (CVN), which mediate vestibulo-autonomic responses among other functions. This study examined the responses of CVN neurons of conscious cats to rotations in vertical planes, both before and after a bilateral vestibular neurectomy. None of the units included in the data sample had eye movement-related activity. In labyrinth-intact animals, some CVN neurons (22%) exhibited graviceptive responses consistent with inputs from otolith organs, but most (55%) had dynamic responses with phases synchronized with stimulus velocity. Furthermore, the large majority of CVN neurons had response vector orientations that were aligned either near the roll or vertical canal planes, and only 18% of cells were preferentially activated by pitch rotations. Sustained head-up rotations of the body provide challenges to the cardiovascular system and breathing, and thus the response dynamics of the large majority of CVN neurons were dissimilar to those of posturally-related autonomic reflexes. These data suggest that vestibular influences on autonomic control mediated by the CVN are more complex than previously envisioned, and likely involve considerable processing and integration of signals by brainstem regions involved in cardiovascular and respiratory regulation. Following a bilateral vestibular neurectomy, CVN neurons regained spontaneous activity within 24 h, and a very few neurons (<10%) responded to vertical tilts <15° in amplitude. These findings indicate that nonlabyrinthine inputs are likely important in sustaining the activity of CVN neurons; thus, these inputs may play a role in functional recovery following peripheral vestibular lesions. PMID:18368395

Cervical Vestibular-Evoked Myogenic Potentials: Norms and Protocols

PubMed Central

Isaradisaikul, Suwicha; Navacharoen, Niramon; Hanprasertpong, Charuk; Kangsanarak, Jaran

2012-01-01

Vestibular-evoked myogenic potential (VEMP) testing is a vestibular function test used for evaluating saccular and inferior vestibular nerve function. Parameters of VEMP testing include VEMP threshold, latencies of p1 and n1, and p1-n1 interamplitude. Less commonly used parameters were p1-n1 interlatency, interaural difference of p1 and n1 latency, and interaural amplitude difference (IAD) ratio. This paper recommends using air-conducted 500 Hz tone burst auditory stimulation presented monoaurally via an inserted ear phone while the subject is turning his head to the contralateral side in the sitting position and recording the responses from the ipsilateral sternocleidomastoid muscle. Normative values of VEMP responses in 50 normal audiovestibular volunteers were presented. VEMP testing protocols and normative values in other literature were reviewed and compared. The study is beneficial to clinicians as a reference guide to set up VEMP testing and interpretation of the VEMP responses. PMID:22577386

Visual and vestibular induced eye movements in verbal children and adults with autism

PubMed Central

Furman, Joseph M.; Osorio, Maria Joana; Minshew, Nancy J.

2016-01-01

This study investigated several types of eye movements that rely on the function of brainstem-cerebellar pathways specifically (vestibular-ocular reflexes) or on widely distributed pathways of the brain (horizontal pursuit and saccade eye movements). Although eye movements that rely on higher brain regions have been studies fairly extensively in autism, eye movements dependent on brainstem and cerebellum have not. This study involved 79 individuals with autism and 62 typical controls aged 5 to 52 years with IQ scores above 70. No differences between the autism and control groups were present on the measures of vestibular ocular reflexes, or on saccade velocity or accuracy. The autism group was significantly slower to initiate saccades, which was most prominent in the 8-18 year old age range. These findings provide the most substantial evidence to date of the functional integrity of brainstem and cerebellar pathways in autism, suggesting that the histopathological abnormalities described in these structures may not be associated with intrinsic dysfunction but rather reflect developmental alterations related to forebrain cortical systems formation. The increase in saccade latency adds to the substantial evidence of altered function and maturation of cortical systems in autism. Objective This study assessed the functionality of vestibular, pursuit and saccade circuitry in autism across a wide age range. Methods Subjects were 79 individuals with autism (AUT) and 62 controls (CON) aged 5 to 52 years with IQ scores > 70. For vestibular testing, earth-vertical axis rotation was performed in darkness and in a lighted visual surround with a fixation target. Ocular motor testing included assessment of horizontal saccades and horizontal smooth pursuit. Results No between-group differences were found in vestibular reflexes or in mean saccade velocity or accuracy. Saccade latency was increased in the AUT group with significant age-related effects in the 8-18 year old subgroups. There was a trend toward decreased pursuit gain without age effects. Conclusions Normal vestibular-induced eye movements and normal saccade accuracy and velocity provide the most substantial evidence to date of the functional integrity of brainstem and cerebellar pathways in autism, suggesting that the histopathological abnormalities described in these structures may not be associated with intrinsic dysfunction but rather reflect developmental alterations related to forebrain cortical systems formation. Increased saccade latency with age effects adds to the extensive existing evidence of altered function and maturation of cortical systems in autism. PMID:25846907

Maternal susceptibility to nausea and vomiting of pregnancy: is the vestibular system involved?

NASA Technical Reports Server (NTRS)

Black, F. Owen

2002-01-01

Nausea and vomiting of pregnancy shares many characteristics with motion sickness, a vestibular dependent phenomenon. A number of physiologic changes that occur in normal pregnancy are also known to accompany nausea and vomiting in patients with motion sickness and certain vestibular disorders. This chapter summarizes some shared features of both phenomena. The unmasking of subclinical vestibular disorders may account for some cases of hyperemesis gravidarum. Hormonal effects on neurotransmitter function may also play a role in nausea and vomiting of pregnancy and in some vestibular disorders; however, the specific neural mechanisms of nausea and vomiting have not been identified. Until the neurochemical processes underlying these phenomena are understood, prevention and management will remain in the domain of astute, but so far limited, clinical observation.

Correlation of Fos expression and circling asymmetry during gerbil vestibular compensation

NASA Technical Reports Server (NTRS)

Kaufman, G. D.; Shinder, M. E.; Perachio, A. A.

1999-01-01

Vestibular compensation is a central nervous system process resulting in recovery of functional movement and control following a unilateral vestibular lesion. Small pressure injections of phosphorothioate 20mer oligonucleotides were used to probe the role of the Fos transcription protein during vestibular compensation in the gerbil brainstem. During isoflurane gas anesthesia, antisense probes against the c-fos mRNA sequence were injected into the medial vestibular and prepositus nuclei unilaterally prior to a unilateral surgical labyrinthectomy. Anionic dyes, which did not interact with the oligonucleotides, were used to mark the injection site and help determine the extent of diffusion. The antiFos oligonucleotide injections reduced Fos expression at the injection site in neurons which normally express Fos after the lesion, and also affected circling behavior induced by hemilabyrinthectomy. With both ipsilateral and contralateral medial vestibular and prepositus nuclei injections, less ipsilateral and more contralateral circling was noted in animals injected with antiFos injections as compared to non-injected controls. The degree of change in these behaviors was dependent upon the side of the injection. Histologically, antiFos injections reduced the number of Fos immunolabeled neurons around the injection site, and increased Fos expression contralaterally. The correlation of the number of neurons with Fos expression to turning behavior was stronger for contralateral versus ipsilateral turns, and for neurons in the caudal and ipsilateral sub-regions of the medial vestibular and prepositus nuclei. The results are discussed in terms of neuronal firing activity versus translational activity based on the asymmetrical expression of the Fos inducible transcription factor in the medial vestibular and prepositus nuclei. Although ubiquitous in the brain, transcription factors like Fos can serve localized and specific roles in sensory-specific adaptive stimuli. Antisense injections can be an effective procedure for localized intervention into complex physiological functions, e.g. vestibular compensation. Copyright 1999 Elsevier Science B.V.

Where is straight ahead to a patient with unilateral vestibular loss?

PubMed

Saj, Arnaud; Honoré, Jacques; Bernard-Demanze, Laurence; Devèze, Arnaud; Magnan, Jacques; Borel, Liliane

2013-05-01

The vestibular system is classically associated with postural control, oculomotor reflexes and self-motion perception. The patients with vestibular loss are primarily concerned with balance and gait problems including head and trunk tilt and walking trajectory deviation to the lesioned side. These long-lasting postural and locomotor biases are thought to originate from changes in spatial perception of self. Indeed, we show here that vestibular cues are necessary for an accurate representation of body orientation. Patients with right (RVN; n=11) or left vestibular neurotomy (LVN; 9) as a treatment for Menière's disease were compared with 10 healthy controls. The subjective straight ahead (SSA) was investigated using a method disentangling lateral shift and tilt components of error. In the horizontal plane, subjects were required to align a rod with their body midline. In the frontal plane, they were asked to align the rod with the midline of head or trunk. The analysis of SSA clearly showed distinct results according to the side of the lesion. The LVN patients had a contralesional lateral shift of SSA. In addition, they showed an ipsilesional tilt, more severe for the head than for the trunk. By contrast, in RVN patients, the representation of the body midline was fairly accurate in both the horizontal and frontal planes and did not differ from that of control subjects. The present study shows deviations in body orientation representation after unilateral vestibular loss. Deviations are observed in the horizontal as well as in the frontal planes. Interestingly, only patients with left vestibular loss were concerned with these changes in perception of self-orientation in space. These data support the hypothesis of an asymmetric vestibular function in healthy subjects and confirm the similarity of functional disorders in patients with vestibular deficits or spatial neglect. For the first time, this similarity is found at the level of body representation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Vestibular Assessment and Rehabilitation: Ten-Year Survey Trends of Audiologists' Opinions and Practice.

PubMed

Nelson, M Dawn; Akin, Faith W; Riska, Kristal M; Andresen, Kimberly; Mondelli, Stephanie Stamps

2016-02-01

The past decade has yielded changes in the education and training of audiologists and technological advancements that have become widely available for clinical balance function testing. It is unclear if recent advancements in vestibular instrumentation or the transition to an AuD degree have affected audiologists' vestibular clinical practice or opinions. The purpose of this study was to examine predominant opinions and practices for vestibular assessment (VA) and vestibular rehabilitation (VR) over the past decade and between master's- and AuD-level audiologists. A 31-question survey was administered to audiologists via U.S. mail in 2003 (N = 7,500) and electronically in 2014 (N = 9,984) with a response rate of 12% and 10%, respectively. There was an increase in the number of audiologists providing vestibular services in the past decade. Most respondents agreed that audiologists were the most qualified professionals to conduct VA. Less than half of the surveyed audiologists felt that graduate training was adequate for VA. AuD-level audiologists were more satisfied with graduate training and felt more comfortable performing VA compared to master's-level audiologists. Few respondents agreed that audiologists were the most qualified professionals to conduct VR or that graduate training prepared them to conduct VR. The basic vestibular test battery was unchanged across surveys and included: calorics, smooth pursuit, saccades, search for spontaneous, positional, gaze and optokinetic nystagmus, Dix-Hallpike, case history, and hearing evaluation. There was a trend toward greater use of air (versus water) calorics, videonystagmography (versus electronystagmography), and additional tests of vestibular and balance function. VA is a growing specialty area in the field of audiology. Better training opportunities are needed to increase audiologists' knowledge and skills for providing vestibular services. The basic tests performed during VA have remained relatively unchanged over the past 10 yr. American Academy of Audiology.

Morphological correlation between caloric tests and vestibular hydrops in Ménière's disease using intravenous Gd enhanced inner ear MRI.

PubMed

Choi, Ji Eun; Kim, Yi-Kyung; Cho, Young Sang; Lee, Kieun; Park, Hyun Woo; Yoon, Sung Hoon; Kim, Hyung-Jin; Chung, Won-Ho

2017-01-01

The purpose of this study was to prove the hypothesis that caloric response in Ménière's disease (MD) is reduced by hydropic expansion of the vestibular labyrinth, not by vestibular hypofunction, by evaluating the correlation morphologically using an intravenous Gadolinium (IV-Gd) inner ear MRI. In study I, the prevalence of abnormal video Head Impulse Test (vHIT) results among the patients with definite unilateral MD (n = 24) and vestibular neuritis (VN) (n = 22) were investigated. All patients showed abnormal canal paresis (CP) (> 26%) on caloric tests. The prevalence of abnormal vHIT in patients with abnormal CP was significantly lower in MD patients (12.5%) than that in VN patients (81.8%) (p < 0.001). In study II, morphological correlation between caloric tests and vestibular hydrops level was evaluated in unilateral MD patients (n = 16) who had normal vHIT results. Eleven patients (61%) had abnormal CP. After taking the images of IV-Gd inner ear MRI, the vestibular hydrops ratio (endolymph volume/total lymph volume = %VH) was measured. In addition, the relative vestibular hydrops ratio (%RVH = (%VHaffected ear-%VHunaffected ear) / (%VHaffected ear + %VHunaffected ear)) was calculated. Each ratio (%VH and %RVH) was compared with average peak slow phase velocity (PSPV) and CP, respectively. In the MD patients, %VH of the affected ear correlated significantly with mean PSPV on the same side (rs = -0.569, p = 0.024), while %RVH correlated significantly with CP (rs = 0.602, p = 0.014). In most MD patients (87.5%) compared to VN patients, vHIT results were normal even though the caloric function was reduced. In addition, the reduced caloric function with normal vHIT was related to the severity of the vestibular hydrops measured by the IV-Gd inner ear MRI. These findings concluded that the abnormal caloric tests with normal vHIT in MD indicated severe endolymphatic hydrops rather than vestibular hypofunction.

FAR and NEAR Target Dynamic Visual Acuity: A Functional Assessment of Canal and Otolith Performance

NASA Technical Reports Server (NTRS)

Peters, Brian T.; Brady, Rachel A.; Landsness, Eric C.; Black, F. Owen; Bloomberg, Jacob J.

2004-01-01

Upon their return to earth, astronauts experience the effects of vestibular adaptation to microgravity. The postflight changes in vestibular information processing can affect postural and locomotor stability and may lead to oscillopsia during activities of daily living. However, it is likely that time spent in microgravity affects canal and otolith function differently. As a result, the isolated rotational stimuli used in traditional tests of canal function may fail to identify vestibular deficits after spaceflight. Also, the functional consequences of deficits that are identified often remain unknown. In a gaze control task, the relative contributions of the canal and otolith organs are modulated with viewing distance. The ability to stabilize gaze during a perturbation, on visual targets placed at different distances from the head may therefore provide independent insight into the function of this systems. Our goal was to develop a functional measure of gaze control that can also offer independent information about the function of the canal and otolith organs.

Symptoms Associated with Vestibular Impairment in Veterans with Posttraumatic Stress Disorder

PubMed Central

2016-01-01

Posttraumatic stress disorder (PTSD) is a chronic and disabling, anxiety disorder resulting from exposure to life threatening events such as a serious accident, abuse or combat (DSM IV definition). Among veterans with PTSD, a common complaint is dizziness, disorientation and/or postural imbalance in environments such as grocery stores and shopping malls. The etiology of these symptoms in PTSD is poorly understood and some attribute them to anxiety or traumatic brain injury. There is a possibility that an impaired vestibular system may contribute to these symptoms since, symptoms of an impaired vestibular system include dizziness, disorientation and postural imbalance. To our knowledge, this is the first report to describe the nature of vestibular related symptoms in veterans with and without PTSD. We measured PTSD symptoms using the Posttraumatic Stress Disorder Checklist (PCL-C) and compared it to responses on vestibular function scales including the Dizziness Handicap Inventory (DHI), the Vertigo Symptom Scale Short Form (VSS-SF), the Chambless Mobility Inventory (CMI), and the Neurobehavioral Scale Inventory (NSI) in order to identify vestibular-related symptoms. Our findings indicate that veterans with worse PTSD symptoms report increased vestibular related symptoms. Additionally veterans with PTSD reported 3 times more dizziness related handicap than veterans without PTSD. Veterans with increased avoidance reported more vertigo and dizziness related handicap than those with PTSD and reduced avoidance. We describe possible contributing factors to increased reports of vestibular symptoms in PTSD, namely, anxiety, a vestibular component as well as an interactive effect of anxiety and vestibular impairment. We also present some preliminary analyses regarding the contribution of TBI. This data suggests possible evidence for vestibular symptom reporting in veterans with PTSD, which may be explained by possible underlying vestibular impairment, worthy of further exploration. PMID:28033352

Model-based Vestibular Afferent Stimulation: Modular Workflow for Analyzing Stimulation Scenarios in Patient Specific and Statistical Vestibular Anatomy.

PubMed

Handler, Michael; Schier, Peter P; Fritscher, Karl D; Raudaschl, Patrik; Johnson Chacko, Lejo; Glueckert, Rudolf; Saba, Rami; Schubert, Rainer; Baumgarten, Daniel; Baumgartner, Christian

2017-01-01

Our sense of balance and spatial orientation strongly depends on the correct functionality of our vestibular system. Vestibular dysfunction can lead to blurred vision and impaired balance and spatial orientation, causing a significant decrease in quality of life. Recent studies have shown that vestibular implants offer a possible treatment for patients with vestibular dysfunction. The close proximity of the vestibular nerve bundles, the facial nerve and the cochlear nerve poses a major challenge to targeted stimulation of the vestibular system. Modeling the electrical stimulation of the vestibular system allows for an efficient analysis of stimulation scenarios previous to time and cost intensive in vivo experiments. Current models are based on animal data or CAD models of human anatomy. In this work, a (semi-)automatic modular workflow is presented for the stepwise transformation of segmented vestibular anatomy data of human vestibular specimens to an electrical model and subsequently analyzed. The steps of this workflow include (i) the transformation of labeled datasets to a tetrahedra mesh, (ii) nerve fiber anisotropy and fiber computation as a basis for neuron models, (iii) inclusion of arbitrary electrode designs, (iv) simulation of quasistationary potential distributions, and (v) analysis of stimulus waveforms on the stimulation outcome. Results obtained by the workflow based on human datasets and the average shape of a statistical model revealed a high qualitative agreement and a quantitatively comparable range compared to data from literature, respectively. Based on our workflow, a detailed analysis of intra- and extra-labyrinthine electrode configurations with various stimulation waveforms and electrode designs can be performed on patient specific anatomy, making this framework a valuable tool for current optimization questions concerning vestibular implants in humans.

Postural Compensation for Unilateral Vestibular Loss

PubMed Central

Peterka, Robert J.; Statler, Kennyn D.; Wrisley, Diane M.; Horak, Fay B.

2011-01-01

Postural control of upright stance was investigated in well-compensated, unilateral vestibular loss (UVL) subjects compared to age-matched control subjects. The goal was to determine how sensory weighting for postural control in UVL subjects differed from control subjects, and how sensory weighting related to UVL subjects’ functional compensation, as assessed by standardized balance and dizziness questionnaires. Postural control mechanisms were identified using a model-based interpretation of medial–lateral center-of-mass body-sway evoked by support-surface rotational stimuli during eyes-closed stance. The surface-tilt stimuli consisted of continuous pseudorandom rotations presented at four different amplitudes. Parameters of a feedback control model were obtained that accounted for each subject’s sway response to the surface-tilt stimuli. Sensory weighting factors quantified the relative contributions to stance control of vestibular sensory information, signaling body-sway relative to earth-vertical, and proprioceptive information, signaling body-sway relative to the surface. Results showed that UVL subjects made significantly greater use of proprioceptive, and therefore less use of vestibular, orientation information on all tests. There was relatively little overlap in the distributions of sensory weights measured in UVL and control subjects, although UVL subjects varied widely in the amount they could use their remaining vestibular function. Increased reliance on proprioceptive information by UVL subjects was associated with their balance being more disturbed by the surface-tilt perturbations than control subjects, thus indicating a deficiency of balance control even in well-compensated UVL subjects. Furthermore, there was some tendency for UVL subjects who were less able to utilize remaining vestibular information to also indicate worse functional compensation on questionnaires. PMID:21922014

Anxiety and depression among patients with different types of vestibular peripheral vertigo.

PubMed

Yuan, Qing; Yu, Lisheng; Shi, Dongmei; Ke, Xingxing; Zhang, Hua

2015-02-01

Numerous studies have been published on comorbid anxiety and depression in patients with vertigo. However, very few studies have separately described and analyzed anxiety or depression in patients with different types of vestibular peripheral vertigo. The present study investigated anxiety and depression among patients with 4 different types of peripheral vertigo. A total of 129 patients with 4 types of peripheral vertigo, namely, benign paroxysmal positional vertigo (BPPV, n = 49), migrainous vertigo (MV, n = 37), Menière disease (MD, n = 28), and vestibular neuritis (VN, n = 15), were included in the present study. Otological and neurootological examinations were carefully performed, and self-rating anxiety scale and self-rating depression scale were used to evaluate anxiety and depression. Patients were divided into 2 groups, according to the vestibular function: normal and abnormal vestibular function. There was no significant difference in the risk of anxiety/depression between these 2 groups. However, for patients with the 4 different vertigo types, the prevalence of anxiety (MV = 45.9%, MD = 50%) and depression (MV = 27%, MD = 28.6%) was significantly higher in the patients with MV or MD than those with BPPV or VN (P < 0.05). Vestibular function is not significantly associated with the risk of anxiety/depression. Anxiety/depression is more common in patients with MV or MD than those with BPPV or VN. This may be due to the different mechanisms involved in these 4 types of vertigo, as well as differences in the prevention and self-control of the patients against the vertigo.

Anxiety and Depression Among Patients With Different Types of Vestibular Peripheral Vertigo

PubMed Central

Yuan, Qing; Yu, Lisheng; Shi, Dongmei; Ke, Xingxing; Zhang, Hua

2015-01-01

Abstract Numerous studies have been published on comorbid anxiety and depression in patients with vertigo. However, very few studies have separately described and analyzed anxiety or depression in patients with different types of vestibular peripheral vertigo. The present study investigated anxiety and depression among patients with 4 different types of peripheral vertigo. A total of 129 patients with 4 types of peripheral vertigo, namely, benign paroxysmal positional vertigo (BPPV, n = 49), migrainous vertigo (MV, n = 37), Menière disease (MD, n = 28), and vestibular neuritis (VN, n = 15), were included in the present study. Otological and neurootological examinations were carefully performed, and self-rating anxiety scale and self-rating depression scale were used to evaluate anxiety and depression. Patients were divided into 2 groups, according to the vestibular function: normal and abnormal vestibular function. There was no significant difference in the risk of anxiety/depression between these 2 groups. However, for patients with the 4 different vertigo types, the prevalence of anxiety (MV = 45.9%, MD = 50%) and depression (MV = 27%, MD = 28.6%) was significantly higher in the patients with MV or MD than those with BPPV or VN (P < 0.05). Vestibular function is not significantly associated with the risk of anxiety/depression. Anxiety/depression is more common in patients with MV or MD than those with BPPV or VN. This may be due to the different mechanisms involved in these 4 types of vertigo, as well as differences in the prevention and self-control of the patients against the vertigo. PMID:25654382

A BMP-mediated transcriptional cascade involving Cash1 and Tlx-3 specifies first-order relay sensory neurons in the developing hindbrain.

PubMed

Hornbruch, Amata; Ma, Grace; Ballermann, Mark A; Tumova, Katerina; Liu, Dan; Cairine Logan, C

2005-07-01

The divergent homeobox-containing transcription factor, Tlx-3 (also known as Hox11L2/Rnx), is required for proper formation of first-order relay sensory neurons in the developing vertebrate brainstem. To date, however, the inductive signals and transcriptional regulatory cascade underlying their development are poorly understood. We previously isolated the chick Tlx-3 homologue and showed it is expressed early (i.e. beginning at HH15) in distinct subcomponents of both the trigeminal/solitary and vestibular nuclei. Here we show via in vivo rhombomere inversions that expression of Tlx-3 is under control of local environmental signals. Our RNA in situ analysis shows expression of the BMP-specific receptor, Bmpr-1b, correlates well with Tlx-3. Furthermore, manipulation of the BMP signaling pathway in vivo via electroporation of expression vectors encoding either BMP or NOGGIN coupled with MASH1 gain-of-function experiments demonstrate that a BMP-mediated transcriptional cascade involving Cash1 and Tlx-3 specifies first-order relay sensory neurons in the developing brainstem. Notably, high-level Noggin misexpression results in an increase in newly differentiated Tlx-3+ neurons that correlates with a corresponding increase in the number of Calretinin+ neurons in vestibular nuclei at later developmental stages strongly suggesting that Tlx-3, in addition to being required for proper formation of somatic as well as visceral sensory neurons in the trigeminal and solitary nuclei, respectively, is sufficient for proper formation of special somatic sensory neurons in vestibular nuclei.

Ephrin-B2 governs morphogenesis of endolymphatic sac and duct epithelia in the mouse inner ear.

PubMed

Raft, Steven; Andrade, Leonardo R; Shao, Dongmei; Akiyama, Haruhiko; Henkemeyer, Mark; Wu, Doris K

2014-06-01

Control over ionic composition and volume of the inner ear luminal fluid endolymph is essential for normal hearing and balance. Mice deficient in either the EphB2 receptor tyrosine kinase or the cognate transmembrane ligand ephrin-B2 (Efnb2) exhibit background strain-specific vestibular-behavioral dysfunction and signs of abnormal endolymph homeostasis. Using various loss-of-function mouse models, we found that Efnb2 is required for growth and morphogenesis of the embryonic endolymphatic epithelium, a precursor of the endolymphatic sac (ES) and duct (ED), which mediate endolymph homeostasis. Conditional inactivation of Efnb2 in early-stage embryonic ear tissues disrupted cell proliferation, cell survival, and epithelial folding at the origin of the endolymphatic epithelium. This correlated with apparent absence of an ED, mis-localization of ES ion transport cells relative to inner ear sensory organs, dysplasia of the endolymph fluid space, and abnormally formed otoconia (extracellular calcite-protein composites) at later stages of embryonic development. A comparison of Efnb2 and Notch signaling-deficient mutant phenotypes indicated that these two signaling systems have distinct and non-overlapping roles in ES/ED development. Homozygous deletion of the Efnb2 C-terminus caused abnormalities similar to those found in the conditional Efnb2 null homozygote. Analyses of fetal Efnb2 C-terminus deletion heterozygotes found mis-localized ES ion transport cells only in the genetic background exhibiting vestibular dysfunction. We propose that developmental dysplasias described here are a gene dose-sensitive cause of the vestibular dysfunction observed in EphB-Efnb2 signaling-deficient mice. Published by Elsevier Inc.

Ephrin-B2 governs morphogenesis of endolymphatic sac and duct epithelia in the mouse inner ear

PubMed Central

Raft, Steven; Andrade, Leonardo R.; Shao, Dongmei; Akiyama, Haruhiko; Henkemeyer, Mark; Wu, Doris K.

2014-01-01

Control over ionic composition and volume of the inner ear luminal fluid endolymph is essential for normal hearing and balance. Mice deficient in either the EphB2 receptor tyrosine kinase or the cognate transmembrane ligand ephrin-B2 (Efnb2) exhibit background strain-specific vestibular behavioral dysfunction and signs of abnormal endolymph homeostasis. Using various loss-of-function mouse models, we found that Efnb2 is required for growth and morphogenesis of the embryonic endolymphatic epithelium, a precursor of the endolymphatic sac (ES) and duct (ED), which mediate endolymph homeostasis. Conditional inactivation of Efnb2 in early-stage embryonic ear tissues disrupted cell proliferation, cell survival, and epithelial folding at the origin of the endolymphatic epithelium. This correlated with apparent absence of an ED, mis-localization of ES ion transport cells relative to inner ear sensory organs, dysplasia of the endolymph fluid space, and abnormally formed otoconia (extracellular calcite protein composites) at later stages of embryonic development. A comparison of Efnb2 and Notch signaling deficient mutant phenotypes indicated that these two signaling systems have distinct and non overlapping roles in ES/ED development. Homozygous deletion of the Efnb2 C terminus caused abnormalities similar to those found in the conditional Efnb2 null homozygote. Analyses of fetal Efnb2 C-terminus deletion heterozygotes found mis-localized ES ion transport cells only in the genetic background exhibiting vestibular dysfunction. We propose that developmental dysplasias described here are a gene dose sensitive cause of the vestibular dysfunction observed in EphB-Efnb2 signaling-deficient mice. PMID:24583262

Vibration-induced nystagmus in patients with vestibular schwannoma: Characteristics and clinical implications.

PubMed

Lee, Jeon Mi; Kim, Mi Joo; Kim, Jin Won; Shim, Dae Bo; Kim, Jinna; Kim, Sung Huhn

2017-07-01

To investigate the clinical significance of vibration-induced nystagmus (VIN) in unilateral vestibular asymmetry and vestibular schwannoma. Thirteen patients with vestibular schwannoma underwent the VIN test, in which stimulation was applied to the mastoid processes and sternocleidomastoid (SCM) muscles on the ipsilateral and contralateral sides of lesions. Preoperative VIN was measured, and changes in VIN were followed up for 6months after tumor removal. Significance of VIN was determined by evaluation of its sensitivity, correlation with vestibular function tests and tumor volume, and postoperative changes. The overall pre and postoperative sensitivities of VIN were 92.3% and 100%, respectively, considering stimulation at all four sites. Maximum slow-phase velocity (MSPV) of VIN was linearly correlated with caloric weakness and tumor volume, especially when stimulation was applied to the SCM muscle. Postoperative MSPV of VIN exhibited stronger linear correlation with postoperative changes in canal paresis value and inverse correlation with tumor size upon stimulation of the ipsilateral SCM muscle than upon stimulation of other sites. During the 6-month follow-up period, persistence of VIN without changes in MSPV was observed even after vestibular compensation. Evoking VIN by stimulation of the mastoid processes and SCM muscles is effective for detecting vestibular asymmetry. It could also help determine the degree of vestibular asymmetry and volume of vestibular schwannoma if stimulation is applied to the SCM muscle. The results of this study could provide clues for the basic application of VIN in patients with vestibular loss and vestibular schwannoma. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Adaptation to vestibular disorientation. XI, The influence of specific and nonspecific gravi-receptors on nystagmic responses to angular acceleration.

DOT National Transportation Integrated Search

1969-10-01

Data from several recent experiments indicate that the otoliths (detectors of linear acceleration) may exert regulatory effects on responses of the semicircular canals (detectors of angular acceleration). This study was designed to explore further th...

Prognostic significance of electrophysiological tests for facial nerve outcome in vestibular schwannoma surgery.

PubMed

van Dinther, J J S; Van Rompaey, V; Somers, T; Zarowski, A; Offeciers, F E

2011-01-01

To assess the prognostic significance of pre-operative electrophysiological tests for facial nerve outcome in vestibular schwannoma surgery. Retrospective study design in a tertiary referral neurology unit. We studied a total of 123 patients with unilateral vestibular schwannoma who underwent microsurgical removal of the lesion. Nine patients were excluded because they had clinically abnormal pre-operative facial function. Pre-operative electrophysiological facial nerve function testing (EPhT) was performed. Short-term (1 month) and long-term (1 year) post-operative clinical facial nerve function were assessed. When pre-operative facial nerve function, evaluated by EPhT, was normal, the outcome from clinical follow-up at 1-month post-operatively was excellent in 78% (i.e. HB I-II) of patients, moderate in 11% (i.e. HB III-IV), and bad in 11% (i.e. HB V-VI). After 1 year, 86% had excellent outcomes, 13% had moderate outcomes, and 1% had bad outcomes. Of all patients with normal clinical facial nerve function, 22% had an abnormal EPhT result and 78% had a normal result. No statistically significant differences could be observed in short-term and long-term post-operative facial function between the groups. In this study, electrophysiological tests were not able to predict facial nerve outcome after vestibular schwannoma surgery. Tumour size remains the best pre-operative prognostic indicator of facial nerve function outcome, i.e. a better outcome in smaller lesions.

Neural substrates linking balance control and anxiety

NASA Technical Reports Server (NTRS)

Balaban, Carey D.

2002-01-01

This communication provides an update of our understanding of the neurological bases for the close association between balance control and anxiety. New data suggest that a vestibulo-recipient region of the parabrachial nucleus (PBN) contains cells that respond to body rotation and position relative to gravity. The PBN, with its reciprocal relationships with the extended central amygdaloid nucleus, infralimbic cortex, and hypothalamus, appears to be an important node in a primary network that processes convergent vestibular, somatic, and visceral information processing to mediate avoidance conditioning, anxiety, and conditioned fear responses. Noradrenergic and serotonergic projections to the vestibular nuclei also have parallel connections with anxiety pathways. The coeruleo-vestibular pathway originates in caudal locus coeruleus (LC) and provides regionally specialized noradrenergic input to the vestibular nuclei, which likely mediate effects of alerting and vigilance on the sensitivity of vestibulo-motor circuits. Both serotonergic and nonserotonergic pathways from the dorsal raphe nucleus and the nucleus raphe obscurus also project differentially to the vestibular nuclei, and 5-HT(2A) receptors are expressed in amygdaloid and cortical targets of the PBN. It is proposed that the dorsal raphe nucleus pathway contributes to both (a) a tradeoff between motor and sensory (information gathering) aspects of responses to self-motion and (b) a calibration of the sensitivity of affective responses to aversive aspects of motion. This updated neurologic model continues to be a synthetic schema for investigating the neurological and neurochemical bases for comorbidity of balance disorders and anxiety disorders.

Low-frequency stimulation cancels the high-frequency-induced long-lasting effects in the rat medial vestibular nuclei.

PubMed

Grassi, S; Pettorossi, V E; Zampolini, M

1996-05-15

In rat brainstem slices, we investigated the effects of low-frequency stimulation (LFS) of the primary vestibular afferents on the amplitude of the field potentials evoked in the medial vestibular nuclei (MVN). LFS induced long-term effects, the sign of which depended on whether the vestibular neurons were previously conditioned by HFS. In unconditioned slices, LFS evoked modifications of the responses that were similar to those observed after HFS but had a smaller extension. In fact, LFS caused long-lasting potentiation of the N1 wave in the MVN ventral portion (Vp) and long-lasting depression of the N2 wave in the MVN dorsal portion (Dp), whereas it provoked small and variable effects on the N1 wave. By contrast, when the synaptic transmission was already conditioned, LFS influenced the synaptic responses oppositely, reducing or annulling the HFS long-term effects. This phenomenon was specifically induced by LFS, because HFS was not able to cause it. The involvement of NMDA receptors in mediating the LFS long-term effects was supported by the fact that AP-5 prevented their induction. In addition, the annulment of HFS long-term effects by LFS was also demonstrated by the shift in the latency of the evoked unitary potentials after LFS. In conclusion, we suggest that the reduction of the previously induced conditioning could represent a cancellation mechanism, useful to quickly adapt the vestibular system to continuous different needs and to avoid saturation.

Development of Vestibular Stochastic Resonance as a Sensorimotor Countermeasure: Improving Otolith Ocular and Motor Task Responses

NASA Technical Reports Server (NTRS)

Mulavara, Ajitkumar; Fiedler, Matthew; DeDios,Yiri E.; Galvan, Raquel; Bloomberg, Jacob; Wood, Scott

2011-01-01

Astronauts experience disturbances in sensorimotor function after spaceflight during the initial introduction to a gravitational environment, especially after long-duration missions. Stochastic resonance (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. The goal of our present study is to develop a countermeasure based on vestibular SR that could improve central interpretation of vestibular input and improve motor task responses to mitigate associated risks.

The effect of severity of unilateral vestibular dysfunction on symptoms, disabilities and handicap in vertiginous patients.

PubMed

Bamiou, D E; Davies, R A; McKee, M; Luxon, L M

1999-02-01

This study compares the symptoms, disabilities and handicap, as assessed by means of a questionnaire, in two groups of patients with a unilateral peripheral vestibular disorder: those with a total canal paresis and those with a partial canal paresis, as judged by the duration parameter using the Fitzgerald Hallpike caloric test in the absence of optic fixation. The results of the study indicate that the severity of dizziness, the Dizziness Index (severity x frequency) and the overall level of disabilities related to visual vertigo are less severe in unilateral profound or total loss of vestibular function than in unilateral mild vestibular loss.

Diabetes, vestibular dysfunction, and falls: analyses from the National Health and Nutrition Examination Survey.

PubMed

Agrawal, Yuri; Carey, John P; Della Santina, Charles C; Schubert, Michael C; Minor, Lloyd B

2010-12-01

Patients with diabetes are at increased risk both for falls and for vestibular dysfunction, a known risk factor for falls. Our aims were 1) to further characterize the vestibular dysfunction present in patients with diabetes and 2) to evaluate for an independent effect of vestibular dysfunction on fall risk among patients with diabetes. National cross-sectional survey. Ambulatory examination centers. Adults from the United States aged 40 years and older who participated in the 2001-2004 National Health and Nutrition Examination Survey (n = 5,86). Diagnosis of diabetes, peripheral neuropathy, and retinopathy. Vestibular function measured by the modified Romberg Test of Standing Balance on Firm and Compliant Support Surfaces and history of falling in the previous 12 months. We observed a higher prevalence of vestibular dysfunction in patients with diabetes with longer duration of disease, greater serum hemoglobin A1c levels and other diabetes-related complications, suggestive of a dose-response relationship between diabetes mellitus severity and vestibular dysfunction. We also noted that vestibular dysfunction independently increased the odds of falling more than 2-fold among patients with diabetes (odds ratio, 2.3; 95% confidence interval, 1.1-5.1), even after adjusting for peripheral neuropathy and retinopathy. Moreover, we found that including vestibular dysfunction, peripheral neuropathy, and retinopathy in multivariate models eliminated the significant association between diabetes and fall risk. Vestibular dysfunction may represent a newly recognized diabetes-related complication, which acts as a mediator of the effect of diabetes mellitus on fall risk.

Three-dimensional, virtual reality vestibular rehabilitation for chronic imbalance problem caused by Ménière's disease: a pilot study^.

PubMed

Hsu, Su-Yi; Fang, Te-Yung; Yeh, Shih-Ching; Su, Mu-Chun; Wang, Pa-Chun; Wang, Victoria Y

2017-08-01

The purpose of this study was to evaluate a three-dimensional, virtual reality system for vestibular rehabilitation in patients with intractable Ménière's disease and chronic vestibular dysfunction. We included 70 patients (36 for study, 34 as control) with a chronic imbalance problem caused by uncompensated Ménière's disease. The virtual reality vestibular rehabilitation comprised four training tasks (modified Cawthorne-Cooksey exercises: eye, head, extension, and coordination exercises) performed in six training sessions (in 4 weeks). Measurements of the task scores and balance parameters obtained at the baseline and after final training sessions were compared. A significant improvement was observed in extension and coordination scores. Patients in the early stages of Ménière's disease had a significantly greater improvement in the center of gravity sway and trajectory excursion in the mediolateral direction than did patients in the late stages of Ménière's disease. Mild functional disability attributable to Ménière's disease was a predictor of improvement in the statokinesigram and maximum trajectory excursion in the anteroposterior direction after rehabilitation. The control group showed no significant improvement in almost all parameters. Virtual reality vestibular rehabilitation may be useful in patients with Ménière's disease, particular those in the early stages or having mild functional disability. Implication for rehabilitation Chronic imbalance caused by uncompensated Ménière's disease is an indication for vestibular rehabilitation. The interactive virtual reality video game, when integrated into vestibular rehabilitation exercise protocol, may assist patients who have mild disability Ménière's disease and who cannot benefit from treatment with drugs or surgery. The initial data from this study support the applicability of three-dimensional virtual reality technology in vestibular rehabilitation programs. The technology gives professionals a new tool to guide patients for vestibular rehabilitation exercises through three-dimensional virtual reality video game playing. The virtual reality vestibular exercise game can provide patients a step-wise, interactive, dynamic, three-dimensional, and interesting rehabilitation environment.

Turning semicircular canal function on its head: dinosaurs and a novel vestibular analysis.

PubMed

Georgi, Justin A; Sipla, Justin S; Forster, Catherine A

2013-01-01

Previous investigations have correlated vestibular function to locomotion in vertebrates by scaling semicircular duct radius of curvature to body mass. However, this method fails to discriminate bipedal from quadrupedal non-avian dinosaurs. Because they exhibit a broad range of relative head sizes, we use dinosaurs to test the hypothesis that semicircular ducts scale more closely with head size. Comparing the area enclosed by each semicircular canal to estimated body mass and to two different measures of head size, skull length and estimated head mass, reveals significant patterns that corroborate a connection between physical parameters of the head and semicircular canal morphology. Head mass more strongly correlates with anterior semicircular canal size than does body mass and statistically separates bipedal from quadrupedal taxa, with bipeds exhibiting relatively larger canals. This morphologic dichotomy likely reflects adaptations of the vestibular system to stability demands associated with terrestrial locomotion on two, versus four, feet. This new method has implications for reinterpreting previous studies and informing future studies on the connection between locomotion type and vestibular function.

Turning Semicircular Canal Function on Its Head: Dinosaurs and a Novel Vestibular Analysis

PubMed Central

Georgi, Justin A.; Sipla, Justin S.; Forster, Catherine A.

2013-01-01

Previous investigations have correlated vestibular function to locomotion in vertebrates by scaling semicircular duct radius of curvature to body mass. However, this method fails to discriminate bipedal from quadrupedal non-avian dinosaurs. Because they exhibit a broad range of relative head sizes, we use dinosaurs to test the hypothesis that semicircular ducts scale more closely with head size. Comparing the area enclosed by each semicircular canal to estimated body mass and to two different measures of head size, skull length and estimated head mass, reveals significant patterns that corroborate a connection between physical parameters of the head and semicircular canal morphology. Head mass more strongly correlates with anterior semicircular canal size than does body mass and statistically separates bipedal from quadrupedal taxa, with bipeds exhibiting relatively larger canals. This morphologic dichotomy likely reflects adaptations of the vestibular system to stability demands associated with terrestrial locomotion on two, versus four, feet. This new method has implications for reinterpreting previous studies and informing future studies on the connection between locomotion type and vestibular function. PMID:23516495

Surgical management of vestibular schwannoma: attempted preservation of hearing and facial function.

PubMed

Youssef, T F; Matter, A; Ahmed, M R

2013-05-01

Vestibular schwannomas are benign tumours which usually originate from the vestibular portion of the VIIIth cranial nerve. Treatment options include observation with serial imaging, stereotactic radiation and microsurgical removal. The goal of surgery was complete eradication of tumour with preservation of hearing and facial nerve function. A retrospective review was undertaken of 24 cases of vestibular schwannoma jointly operated upon by a team of neurosurgeons and otologists at the Suez Canal University Hospital, with assessment of VIIth and VIIIth cranial nerve function, tumour size, and extent of growth. All surgery utilised a retromastoid, suboccipital approach. Complete tumour removal was achieved in 19 patients. Anatomical preservation of the facial nerve was possible in 66.6 per cent of patients. Pre-operative, useful hearing was present in four patients, and preserved in 80 per cent. Cerebrospinal fluid leakage was diagnosed in two (8.3 per cent) patients, who responded to conservative therapy. The retromastoid, suboccipital surgical approach to the skull base can be safely and successfully achieved using a microsurgical technique, with minimal or no damage to neurovascular structures, even for large tumours.

Research on biophysical evaluation of the human vestibular system

NASA Technical Reports Server (NTRS)

Young, L. R.

1974-01-01

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.

Sensory processing in the vestibular nuclei during active head movements

NASA Technical Reports Server (NTRS)

Gdowski, G. T.; Boyle, R.; McCrea, R. A.; Peterson, B. W. (Principal Investigator)

2000-01-01

Many secondary vestibular neurons are sensitive to head on trunk rotation during reflex-induced and voluntary head movements. During passive whole body rotation the interaction of head on trunk signals related to the vestibulo-collic reflex with vestibular signals increases the rotational gain of many secondary vestibular neurons, including many that project to the spinal cord. In some units, the sensitivity to head on trunk and vestibular input is matched and the resulting interaction produces an output that is related to the trunk velocity in space. In other units the head on trunk inputs are stronger and the resulting interaction produces an output that is larger during the reflex. During voluntary head movements, inputs related to head on trunk movement combine destructively with vestibular signals, and often cancel the sensory reafferent consequences of self-generated movements. Cancellation of sensory vestibular signals was observed in all of the antidromically identified secondary vestibulospinal units, even though many of these units were not significantly affected by reflexive head on trunk movements. The results imply that the inputs to vestibular neurons related to head on trunk rotation during reflexive and voluntary movements arise from different sources. We suggest that the relative strength of reflexive head on trunk input to different vestibular neurons might reflect the different functional roles they have in controlling the posture of the neck and body.

Vestibular dysfunction in the adult CBA/CaJ mouse after lead and cadmium treatment

PubMed Central

Klimpel, Katarina E. M.; Lee, Min Young; King, W. Michael; Raphael, Yehoash; Schacht, Jochen; Neitzel, Richard L.

2017-01-01

OBJECTIVES The vestibular system allows the perception of position and motion and its dysfunction presents as motion impairment, vertigo and balance abnormalities, leading to debilitating psychological discomfort and difficulty performing daily tasks. Although declines and deficits in vestibular function have been noted in rats exposed to lead (Pb) and in humans exposed to Pb and cadmium (Cd), no studies have directly examined the pathological and pathophysiological effects upon the vestibular apparatus of the inner ear. METHODS Eighteen young adult mice were exposed through their drinking water (3 mM Pb, 300 μM Cd, or a control treatment) for 10 weeks. Before and after treatment, they underwent a vestibular assessment, consisting of a rotarod performance test and a novel head stability test to measure the vestibulocolic reflex. At the conclusion of the study, the utricles were analyzed immunohistologically for condition of hair cells and nerve fibers. RESULTS Increased levels of Pb exposure correlated with decreased head stability in space; no significant decline in performance on rotarod test was found. No damage to the hair cells or the nerve fibers of the utricle was observed in histology. CONCLUSIONS The young adult CBA/CaJ mouse is able to tolerate occupationally-relevant Pb and Cd exposure well, but the correlation between Pb exposure and reduced head stability suggests that Pb exposure causes a decline in vestibular function. PMID:27257108

Vestibular (dys)function in children with sensorineural hearing loss: a systematic review.

PubMed

Verbecque, Evi; Marijnissen, Tessa; De Belder, Niels; Van Rompaey, Vincent; Boudewyns, An; Van de Heyning, Paul; Vereeck, Luc; Hallemans, Ann

2017-06-01

The objective of this study is to provide an overview of the prevalence of vestibular dysfunction in children with SNHL classified according to the applied test and its corresponding sensitivity and specificity. Data were gathered using a systematic search query including reference screening. Pubmed, Web of Science and Embase were searched. Strategy and reporting of this review was based on the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Methodological quality was assessed with the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. All studies, regardless the applied vestibular test, showed that vestibular function differs significantly between children with hearing loss and normal hearing (p < 0.05). Compared with caloric testing, the sensitivity of the Rotational Chair Test (RCT) varies between 61 and 80% and specificity between 21 and 80%, whereas this was, respectively, 71-100% and 30-100% for collic Vestibular Evoked Myogenic Potentials (cVEMP). Compared with RCT, the sensitivity was 88-100% and the specificity was 69-100% for the Dynamic Visual Acuity test, respectively, 67-100% and 71-100% for the (video) Head Impulse Test and 83% and 86% for the ocular VEMP. Currently, due to methodological shortcoming, evidence on sensitivity and specificity of vestibular tests is unknown to moderate. Future research should focus on adequate sample sizes (subgroups >30).

Functional Imaging of Human Vestibular Cortex Activity Elicited by Skull Tap and Auditory Tone Burst

NASA Technical Reports Server (NTRS)

Noohi, F.; Kinnaird, C.; Wood, S.; Bloomberg, J.; Mulavara, A.; Seidler, R.

2016-01-01

The current study characterizes brain activation in response to two modes of vestibular stimulation: skull tap and auditory tone burst. The auditory tone burst has been used in previous studies to elicit either the vestibulo-spinal reflex (saccular-mediated colic Vestibular Evoked Myogenic Potentials (cVEMP)), or the ocular muscle response (utricle-mediated ocular VEMP (oVEMP)). Some researchers have reported that air-conducted skull tap elicits both saccular and utricle-mediated VEMPs, while being faster and less irritating for the subjects. However, it is not clear whether the skull tap and auditory tone burst elicit the same pattern of cortical activity. Both forms of stimulation target the otolith response, which provides a measurement of vestibular function independent from semicircular canals. This is of high importance for studying otolith-specific deficits, including gait and balance problems that astronauts experience upon returning to earth. Previous imaging studies have documented activity in the anterior and posterior insula, superior temporal gyrus, inferior parietal lobule, inferior frontal gyrus, and the anterior cingulate cortex in response to different modes of vestibular stimulation. Here we hypothesized that skull taps elicit similar patterns of cortical activity as the auditory tone bursts, and previous vestibular imaging studies. Subjects wore bilateral MR compatible skull tappers and headphones inside the 3T GE scanner, while lying in the supine position, with eyes closed. Subjects received both forms of the stimulation in a counterbalanced fashion. Pneumatically powered skull tappers were placed bilaterally on the cheekbones. The vibration of the cheekbone was transmitted to the vestibular system, resulting in the vestibular cortical response. Auditory tone bursts were also delivered for comparison. To validate our stimulation method, we measured the ocular VEMP outside of the scanner. This measurement showed that both skull tap and auditory tone burst elicited vestibular evoked myogenic potentials, indicated by eye muscle responses. We further assessed subjects' postural control and its correlation with vestibular cortical activity. Our results provide the first evidence of using skull taps to elicit vestibular activity inside the MRI scanner. By conducting conjunction analyses we showed that skull taps elicit the same activation pattern as auditory tone bursts (superior temporal gyrus), and both modes of stimulation activate previously identified vestibular cortical regions. Additionally, we found that skull taps elicit more robust vestibular activity compared to auditory tone bursts, with less reported aversive effects. This further supports that the skull tap could replace auditory tone burst stimulation in clinical interventions and basic science research. Moreover, we observed that greater vestibular activation is associated with better balance control. We showed that not only the quality of balance (indicated by the amount of body sway) but also the ability to maintain balance for a longer time (indicated by the balance time) was associated with individuals' vestibular cortical excitability. Our findings support an association between vestibular cortical activity and individual differences in balance. In sum, we found that the skull tap stimulation results in activation of canonical vestibular cortex, suggesting an equally valid, but more tolerable stimulation method compared to auditory tone bursts. This is of high importance in longitudinal vestibular assessments, in which minimizing aversive effects may contribute to higher protocol adherence.

Vestibular responses to loud dance music: a physiological basis of the "rock and roll threshold"?

PubMed

Todd, N P; Cody, F W

2000-01-01

In this paper new evidence is provided to indicate that vestibular responses may be obtained from loud dance music for intensities above 90 dB(A) SPL (Impulse-weighted). In a sample of ten subjects acoustically evoked EMG were obtained from the sternocleidomastoid muscle in response to a sample of techno music typical of that which may be experienced in a dance club. Previous research has shown that this response is vestibularly mediated since it can be obtained in subjects with loss of cochlear function, but is absent in subjects with loss of vestibular function (Colebatch et al. [J. Neurol. Neurosurg. Psychiatr. 57, 190-197 (1994)]. Given that pleasurable sensations of self-motion are widely sought after by more normal means of vestibular stimulation, it is suggested that acoustically evoked sensations of self-motion may account for the compulsion to exposure to loud music. Given further the similarity between the thresholds found, and the intensities and frequency distributions that are typical in rock concerts and dance clubs, it is also suggested that this response may be a physiological basis for the minimum loudness necessary for rock and dance music to work-the "rock and roll threshold".

Development of vestibular afferent projections into the hindbrain and their central targets

NASA Technical Reports Server (NTRS)

Maklad, Adel; Fritzsch, Bernd

2003-01-01

In contrast to most other sensory systems, hardly anything is known about the neuroanatomical development of central projections of primary vestibular neurons and how their second order target neurons develop. Recent data suggest that afferent projections may develop not unlike other sensory systems, forming first the overall projection by molecular means followed by an as yet unspecified phase of activity mediated refinement. The latter aspect has not been tested critically and most molecules that guide the initial projection are unknown.The molecular and topological origin of the vestibular and cochlear nucleus neurons is also only partially understood. Auditory and vestibular nuclei form from several rhombomeres and a given rhombomere can contribute to two or more auditory or vestibular nuclei. Rhombomere compartments develop as functional subdivisions from a single column that extends from the hindbrain to the spinal cord. Suggestions are provided for the molecular origin of these columns but data on specific mutants testing these proposals are not yet available. Overall, the functional significance of both overlapping and segregated projections are not yet fully experimentally explored in mammals. Such lack of details of the adult organization compromises future developmental analysis.

Improving Sensorimotor Adaptation Following Long Duration Space Flight by Enhancing Vestibular Information Transfer

NASA Technical Reports Server (NTRS)

Mulavara, A. P.; Kofman, I. S.; De Dios, Y. E; Galvan, R.; Goel, R.; Miller, C.; Peters, B.; Cohen, H. S.; Jeevarajan, J.; Reschke, M.;

[The significance of directional preponderance in the evaluation of vestibular function in patients with vertigo].

PubMed

Wang, J; Zhou, Y J; Yu, J; Gu, J

2017-03-07

Objective: To analyze the relationship between directional preponderance (DP), spontaneous nystagmus(SN) and vestibular disorders, and to investigate the significance of DP in directing peripheral vestibular function in patients with vertigo. Methods: This was a retrospective analysis of 394 cases diagnosed with peripheral vestibular disease accompanied by vertigo from March 2012 to June 2014 in the Outpatient Department of the Eye & ENT Hospital of Fudan University. Results of static and dynamic posture equilibrium tests, SN, unilateral weakness(UW), and DP in videonystagmography(VNG) were analyzed and compared. Results: The mean interval time between the last vertigo attack and examination in patients with SN or DP in caloric test were 4.4 d and 7.3 d respectively, and those without SN or DP were 18.3 d and 17.5 d respectively. The patients were divided into two groups according to DP results of caloric test. DP-normal group had 203 cases and DP-abnormal group had 191 cases. Spontaneous nystagmus was presented in 44 cases in the DP-normal group (21.67%) and four in the DP-abnormal group (2.09%). A significant difference was found between the two groups (χ 2 =35.27, P =0.000). Deficiency of vestibular function was noted in 165 cases in the DP-normal group (81.28%) and 123 (64.40%) in the DP-abnormal group in static and dynamic posture equilibrium tests. The difference between the two groups was statistically significant (χ 2 =14.26, P =0.000). Conclusion: Compared with DP-normal patients, DP-abnormal patients are more likely to have spontaneous nystagmus and balance disorders due to vestibular dysfunction.

Dyscalculia and vestibular function.

PubMed

Smith, P F

2012-10-01

A few studies in humans suggest that changes in stimulation of the balance organs of the inner ear (the 'vestibular system') can disrupt numerical cognition, resulting in 'dyscalculia', the inability to manipulate numbers. Many studies have also demonstrated that patients with vestibular dysfunction exhibit deficits in spatial memory. It is suggested that there may be a connection between spatial memory deficits resulting from vestibular dysfunction and the occurrence of dyscalculia, given the evidence that numerosity is coupled to the processing of spatial information (e.g., the 'spatial numerical association of response codes ('SNARC') effect'). The evidence supporting this hypothesis is summarised and potential experiments to test it are proposed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of gravity changes on gene expression of BDNF and serotonin receptors in the mouse brain.

PubMed

Ishikawa, Chihiro; Li, Haiyan; Ogura, Rin; Yoshimura, Yuko; Kudo, Takashi; Shirakawa, Masaki; Shiba, Dai; Takahashi, Satoru; Morita, Hironobu; Shiga, Takashi

2017-01-01

Spaceflight entails various stressful environmental factors including microgravity. The effects of gravity changes have been studied extensively on skeletal, muscular, cardiovascular, immune and vestibular systems, but those on the nervous system are not well studied. The alteration of gravity in ground-based animal experiments is one of the approaches taken to address this issue. Here we investigated the effects of centrifugation-induced gravity changes on gene expression of brain-derived neurotrophic factor (BDNF) and serotonin receptors (5-HTRs) in the mouse brain. Exposure to 2g hypergravity for 14 days showed differential modulation of gene expression depending on regions of the brain. BDNF expression was decreased in the ventral hippocampus and hypothalamus, whereas increased in the cerebellum. 5-HT1BR expression was decreased in the cerebellum, whereas increased in the ventral hippocampus and caudate putamen. In contrast, hypergravity did not affect gene expression of 5-HT1AR, 5-HT2AR, 5-HT2CR, 5-HT4R and 5-HT7R. In addition to hypergravity, decelerating gravity change from 2g hypergravity to 1g normal gravity affected gene expression of BDNF, 5-HT1AR, 5-HT1BR, and 5-HT2AR in various regions of the brain. We also examined involvement of the vestibular organ in the effects of hypergravity. Surgical lesions of the inner ear's vestibular organ removed the effects induced by hypergravity on gene expression, which suggests that the effects of hypergravity are mediated through the vestibular organ. In summary, we showed that gravity changes induced differential modulation of gene expression of BDNF and 5-HTRs (5-HT1AR, 5-HT1BR and 5-HT2AR) in some brain regions. The modulation of gene expression may constitute molecular bases that underlie behavioral alteration induced by gravity changes.

Effects of gravity changes on gene expression of BDNF and serotonin receptors in the mouse brain

PubMed Central

Yoshimura, Yuko; Kudo, Takashi; Shirakawa, Masaki; Shiba, Dai; Takahashi, Satoru; Morita, Hironobu

2017-01-01

Spaceflight entails various stressful environmental factors including microgravity. The effects of gravity changes have been studied extensively on skeletal, muscular, cardiovascular, immune and vestibular systems, but those on the nervous system are not well studied. The alteration of gravity in ground-based animal experiments is one of the approaches taken to address this issue. Here we investigated the effects of centrifugation-induced gravity changes on gene expression of brain-derived neurotrophic factor (BDNF) and serotonin receptors (5-HTRs) in the mouse brain. Exposure to 2g hypergravity for 14 days showed differential modulation of gene expression depending on regions of the brain. BDNF expression was decreased in the ventral hippocampus and hypothalamus, whereas increased in the cerebellum. 5-HT1BR expression was decreased in the cerebellum, whereas increased in the ventral hippocampus and caudate putamen. In contrast, hypergravity did not affect gene expression of 5-HT1AR, 5-HT2AR, 5-HT2CR, 5-HT4R and 5-HT7R. In addition to hypergravity, decelerating gravity change from 2g hypergravity to 1g normal gravity affected gene expression of BDNF, 5-HT1AR, 5-HT1BR, and 5-HT2AR in various regions of the brain. We also examined involvement of the vestibular organ in the effects of hypergravity. Surgical lesions of the inner ear’s vestibular organ removed the effects induced by hypergravity on gene expression, which suggests that the effects of hypergravity are mediated through the vestibular organ. In summary, we showed that gravity changes induced differential modulation of gene expression of BDNF and 5-HTRs (5-HT1AR, 5-HT1BR and 5-HT2AR) in some brain regions. The modulation of gene expression may constitute molecular bases that underlie behavioral alteration induced by gravity changes. PMID:28591153

Adaptations of the vestibular system to short and long-term exposures to altered gravity

NASA Astrophysics Data System (ADS)

Bruce, L. L.

2003-10-01

Long-term space flight creates unique environmental conditions to which the vestibular system must adapt for optimal survival of a given organism. The development and maintenance of vestibular connections are controlled by environmental gravitational stimulation as well as genetically controlled molecular interactions. This paper describes the effects of hypergravity on axonal growth and dendritic morphology, respectively. Two aspects of this vestibular adaptation are examined: (1) How does long-term exposure to hypergravity affect the development of vestibular axons? (2) How does short-term exposure to extremely rapid changes in gravity, such as those that occur during shuttle launch and landing, affect dendrites of the vestibulocerebellar system? To study the effects of longterm exposures to altered gravity, embryonic rats that developed in hypergravity were compared to microgravity-exposed and control rats. Examination of the vestibular projections from epithelia devoted to linear and angular acceleration revealed that the terminal fields segregate differently in rat embryos that gestated in each of the gravitational environments.To study the effects of short-term exposures to altered gravity, mice were exposed briefly to strong vestibular stimuli and the vestibulocerebellum was examined for any resulting morphological changes. My data show that these stimuli cause intense vestibular excitation of cerebellar Purkinje cells, which induce up-regulation of clathrin-mediated endocytosis and other morphological changes that are comparable to those seen in long-term depression. This system provides a basis for studying how the vestibular environment can modify cerebellar function, allowing animals to adapt to new environments.

Vestibular influences on autonomic cardiovascular control in humans

NASA Technical Reports Server (NTRS)

Biaggioni, I.; Costa, F.; Kaufmann, H.; Robertson, D. (Principal Investigator)

1998-01-01

There is substantial evidence that anatomical connections exist between vestibular and autonomic nuclei. Animal studies have shown functional interactions between the vestibular and autonomic systems. The nature of these interactions, however, is complex and has not been fully defined. Vestibular stimulation has been consistently found to reduce blood pressure in animals. Given the potential interaction between vestibular and autonomic pathways this finding could be explained by a reduction in sympathetic activity. However, rather than sympathetic inhibition, vestibular stimulation has consistently been shown to increase sympathetic outflow in cardiac and splanchnic vascular beds in most experimental models. Several clinical observations suggest that a link between vestibular and autonomic systems may also exist in humans. However, direct evidence for vestibular/autonomic interactions in humans is sparse. Motion sickness has been found to induce forearm vasodilation and reduce baroreflex gain, and head down neck flexion induces transient forearm and calf vasoconstriction. On the other hand, studies using optokinetic stimulation have found either very small, variable, or inconsistent changes in heart rate and blood pressure, despite substantial symptoms of motion sickness. Furthermore, caloric stimulation severe enough to produce nystagmus, dizziness, and nausea had no effect on sympathetic nerve activity measured directly with microneurography. No effect was observed on heart rate, blood pressure, or plasma norepinephrine. Several factors may explain the apparent discordance of these results, but more research is needed before we can define the potential importance of vestibular input to cardiovascular regulation and orthostatic tolerance in humans.

Vestibular pathways involved in cognition

PubMed Central

Hitier, Martin; Besnard, Stephane; Smith, Paul F.

2014-01-01

Recent discoveries have emphasized the role of the vestibular system in cognitive processes such as memory, spatial navigation and bodily self-consciousness. A precise understanding of the vestibular pathways involved is essential to understand the consequences of vestibular diseases for cognition, as well as develop therapeutic strategies to facilitate recovery. The knowledge of the “vestibular cortical projection areas”, defined as the cortical areas activated by vestibular stimulation, has dramatically increased over the last several years from both anatomical and functional points of view. Four major pathways have been hypothesized to transmit vestibular information to the vestibular cortex: (1) the vestibulo-thalamo-cortical pathway, which probably transmits spatial information about the environment via the parietal, entorhinal and perirhinal cortices to the hippocampus and is associated with spatial representation and self-versus object motion distinctions; (2) the pathway from the dorsal tegmental nucleus via the lateral mammillary nucleus, the anterodorsal nucleus of the thalamus to the entorhinal cortex, which transmits information for estimations of head direction; (3) the pathway via the nucleus reticularis pontis oralis, the supramammillary nucleus and the medial septum to the hippocampus, which transmits information supporting hippocampal theta rhythm and memory; and (4) a possible pathway via the cerebellum, and the ventral lateral nucleus of the thalamus (perhaps to the parietal cortex), which transmits information for spatial learning. Finally a new pathway is hypothesized via the basal ganglia, potentially involved in spatial learning and spatial memory. From these pathways, progressively emerges the anatomical network of vestibular cognition. PMID:25100954

[Diagnosis and treatment options in vertigo syndromes].

PubMed

Strupp, M; Dieterich, M; Zwergal, A; Brandt, T

2015-10-01

The key to diagnosing vertigo and balance disorders is systematic analysis of case history with clinical examination of the vestibular, oculomotor, and cerebral systems in particular. Important criteria for differentiating between the various vertigo syndromes are 1) the time course of symptoms, 2) the type of symptoms, 3) modulating factors, and 4) associated symptoms. For clinical examination of the vestibular system, six important tests are available: assessment of spontaneous nystagmus, head impulse test, dynamic visual acuity, subjective visual verticality, positioning manoeuvre, and the Romberg test/gait analysis with eyes open and closed. On the basis of five clinical signs (vertical divergence, central fixation nystagmus, gaze-evoked nystagmus, saccades, normal head impulse test), the clinical examination is able to differentiate between acute central and peripheral vestibular syndromes with a sensitivity and specificity of over 90%. The most relevant laboratory examinations are caloric irrigation and the video head-impulse test for canal function and the vestibular evoked myogenic potentials for otolith function. Finally, treatment is based upon four therapeutic principles: physiotherapy, pharmacotherapy, psychotherapy, and in rare cases, surgery.

Problems of space biology. Volume 50: Nystagmometry for evaulation of the status of the vestibular function

NASA Technical Reports Server (NTRS)

Levashov, M. M.; Kislyakov, V. A. (Editor)

1985-01-01

Various aspects of nystagmometry are studied, primarily those in which the study of hystagmus serves as a means to learn about the vestibular apparatus. Along with exhaustive published material, the monograph presents data from many years of research on the physioloigical mechanisms of nystagmus, the features of nystagmus when vestibular stimulation is combined with optokinetic, the pole of vertibular afferentation asymmetry in the asymmetry of reactions to optokinetic stimulus, a nystagmometric approach to studying the hydrodynamic interaction among semicircular canals, as well as several other questions. A great deal of attention is given to methods of recording nystagmus, calibrating nystagmograms, quantitative evaluation of nystagmographic material, new nystagmometric characteristics and diagnostic techniques. A diagnostic model is proposed which makes it possible to obtain important information on the condition of the vestibular system from results of vestibular testing.

Vestibular rehabilitation: clinical benefits to patients with Parkinson's disease.

PubMed

Zeigelboim, Bianca Simone; Klagenberg, Karlin Fabianne; Teive, Hélio A Ghizoni; Munhoz, Renato Puppi; Martins-Bassetto, Jackeline

2009-06-01

To evaluate the effectiveness of the vestibular rehabilitation (VR) exercises by means of an assessment before and after the application of the Brazilian version of the Dizziness Handicap Inventory (DHI) questionnaire. Twelve patients were studied, the following procedures were carried out: anamnesis, otorhinolaryngological and vestibular evaluation, and the application of the DHI before and after the VR. Clinically resting tremors and subjective postural instability were the motor complaints most frequently associated with complaints of vertigo in 12 cases (100%); in the vestibular exam, all the patients presented abnormalities, frequently from the uni and bilateral peripheral vestibular deficiency syndromes in 10 cases (83.3%); there was significant improvement in the physical, functional and emotional aspects of the DHI after the completion of the VR. The VR following the Cawthorne and Cooksey protocol were shown to be useful in managing subjective complaints of several aspects evaluated in this protocol.

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

NASA Technical Reports Server (NTRS)

Henley, C.; Igarashi, M.

1993-01-01

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.

Current and Future Management of Bilateral Loss of Vestibular Sensation – An update on the Johns Hopkins Multichannel Vestibular Prosthesis Project

PubMed Central

Della Santina, Charles C.; Migliaccio, Americo A.; Hayden, Russell; Melvin, Thuy-Anh; Fridman, Gene Y.; Chiang, Bryce; Davidovics, Natan S.; Dai, Chenkai; Carey, John P.; Minor, Lloyd B.; Anderson, Iee-Ching; Park, HongJu; Lyford-Pike, Sofia; Tang, Shan

2012-01-01

Bilateral loss of vestibular sensation can disable individuals whose vestibular hair cells are injured by ototoxic medications, infection, Ménière’s disease or other insults to the labyrinth including surgical trauma during cochlear implantation. Without input to vestibulo-ocular and vestibulo-spinal reflexes that normally stabilize the eyes and body, affected patients suffer blurred vision during head movement, postural instability, and chronic disequilibrium. While individuals with some residual sensation often compensate for their loss through rehabilitation exercises, those who fail to do so are left with no adequate treatment options. An implantable neuroelectronic vestibular prosthesis that emulates the normal labyrinth by sensing head movement and modulating activity on appropriate branches of the vestibular nerve could significantly improve quality of life for these otherwise chronically dizzy patients. This brief review describes the impact and current management of bilateral loss of vestibular sensation, animal studies supporting the feasibility of prosthetic vestibular stimulation, and a vestibular prosthesis designed to restore sensation of head rotation in all directions. Similar to a cochlear implant in concept and size, the Johns Hopkins Multichannel Vestibular Prosthesis (MVP) includes miniature gyroscopes to sense head rotation, a microcontroller to process inputs and control stimulus timing, and current sources switched between pairs of electrodes implanted within the vestibular labyrinth. In rodents and rhesus monkeys rendered bilaterally vestibular-deficient via treatment with gentamicin and/or plugging of semicircular canals, the MVP partially restores the vestibulo-ocular reflex for head rotations about any axis of rotation in 3-dimensional space. Our efforts now focus on addressing issues prerequisite to human implantation, including refinement of electrode designs and surgical technique to enhance stimulus selectivity and preserve cochlear function, optimization of stimulus protocols, and reduction of device size and power consumption. PMID:21756683

Examination and treatment of patients with unilateral vestibular damage, with focus on the musculoskeletal system: a case series.

PubMed

Wilhelmsen, Kjersti; Kvåle, Alice

2014-07-01

Persistent dizziness and balance problems have been reported in some patients with unilateral vestibular pathology. The purpose of this case series was to address the examination and treatment of musculoskeletal dysfunction in patients with unilateral vestibular hypofunction. The musculoskeletal system was evaluated with the Global Physiotherapy Examination, dynamic balance was measured during walking with triaxial accelerometers positioned on the lower and upper trunk, and symptoms and functional limitations were assessed with standardized self-report measures. The 4 included patients had symptoms of severe dizziness that had lasted more than 1 year after the onset of vestibular dysfunction and a moderate level of perceived disability. Musculoskeletal abnormalities typically included postural misalignment, restricted abdominal respiration, restricted trunk movements, and tense muscles of the upper trunk and neck. The patients attended a modified vestibular rehabilitation program consisting of body awareness exercises addressing posture, movements, and respiration. After the intervention, self-reported symptoms and perceived disability improved. Improvements in mobility and positive physical changes were found in the upper trunk and respiratory movements. The attenuation of mediolateral accelerations (ie, body oscillations) in the upper trunk changed; a relatively more stable upper trunk and a concomitantly more flexible lower trunk were identified during walking in 3 patients. The recovery process may be influenced by self-inflicted rigid body movements and behavior strategies that prevent compensation. Addressing physical dysfunction and enhancing body awareness directly and dizziness indirectly may help patients with unilateral vestibular hypofunction break a self-sustaining cycle of dizziness and musculoskeletal problems. Considering the body as a functional unit and including both musculoskeletal and vestibular systems in examination and treatment may be important. © 2014 American Physical Therapy Association.

Enhancement of Otolith Specific Ocular Responses Using Vestibular Stochastic Resonance

NASA Technical Reports Server (NTRS)

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

2011-01-01

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.

Health-related quality of life and disability in patients with acute unilateral peripheral vestibular disorders.

PubMed

Petri, Maria; Chirilă, Magdalena; Bolboacă, Sorana D; Cosgarea, Marcel

Health-related quality of life is used to denote that portion of the quality of life that is influenced by the person's health. To compare the health-related quality of life of individuals with vestibular disorders of peripheral origin by analyzing functional, emotional and physical disabilities before and after vestibular treatment. A prospective, non randomized case-controlled study was conduced in the ENT Department, between January 2015 and December 2015. All patients were submitted to customize a 36 item of health survey on quality of life, short form 36 health survey questionnaire (SF-36) and the Dizziness Handicap Inventory for assessing the disability. Individuals were diagnosed with acute unilateral vestibular peripheral disorders classified in 5 groups: vestibular neuritis, Ménière Disease, Benign Paroxysmal Positional Vertigo, cochlear-vestibular dysfunction (other than Ménière Disease), or other type of acute peripheral vertigo (as vestibular migraine). There was a statistical significant difference for each parameter of Dizziness Handicap Inventory score (the emotional, functional and physical) between the baseline and one month both in men and women, but with any statistical significant difference between 7 days and 14 days. It was found a statistical significant difference for all eight parameters of SF-36 score between the baseline and one month later both in men and women; the exception was the men mental health perception. The correlation between the Dizziness Handicap Inventory and the SF-36 scores according to diagnostics type pointed out that the Spearman's correlation coefficient was moderate correlated with the total scores of these instruments. The Dizziness Handicap Inventory and the SF-36 are useful, proved practical and valid instruments for assessing the impact of dizziness on the quality of life of patients with unilateral peripheral vestibular disorders. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Translabyrinthine vestibular neurectomy and simultaneous cochlear implant for Ménière's disease.

PubMed

Canzi, Pietro; Manfrin, Marco; Perotti, Marco; Aprile, Federico; Quaglieri, Silvia; Rebecchi, Elisabetta; Locatelli, Giulia; Benazzo, Marco

2017-01-01

Surgical management of Ménière's disease (MD) is recommended in case of medical and intratympanic treatment failures. Translabyrinthine vestibular nerve section has been considered the gold standard for denervation procedures in order to control vertigo attacks, although at the cost of sacrificing residual hearing. To the best of our knowledge, no work has been published with regard to a group of patients submitted to translabyrinthine vestibular neurectomy and simultaneous cochlear implant for MD. The aim of the present study was to assess the effectiveness of translabyrinthine vestibular nerve section and simultaneous cochlear implant in a prospective study. All adult patients (over 18 years of age) with a diagnosis of intractable unilateral definite MD and useless residual hearing function were enrolled after medical and intratympanic treatment failures. Pre- and postoperative otoneurological evaluation concerned: frequency of vertigo attacks, head impulse test and caloric testing, pure tone average and speech perception audiometry in quiet conditions, tinnitus handicap inventory test, functional level scale and rate of vertigo control, dizziness handicap inventory test, and MD patient-oriented severity index. At least 6 months of follow-up were needed to be enrolled in the study. Four patients were included in the study. Translabyrinthine vestibular nerve section and simultaneous cochlear implant seemed to considerably improve the disabling effects of MD, achieving a good control of vestibular symptoms (mean pre/postoperative vertigo attacks per month: 16.5/0), resolving hearing loss (mean pre/postoperative pure tone average in the affected ear: 86.2/32.5 dB), improving the tinnitus (mean pre/postoperative tinnitus handicap inventory test: 77.2/6), and finally increasing the overall quality-of-life parameters. In our preliminary report, translabyrinthine vestibular nerve section and simultaneous cochlear implant showed encouraging results in order to definitively control both vestibular and cochlear symptoms during the same therapeutic procedure.

Baseline vestibular and auditory findings in a trial of post-concussive syndrome

PubMed

Meehan, Anna; Searing, Elizabeth; Weaver, Lindell; Lewandowski, Andrew

2016-01-01

Previous studies have reported high rates of auditory and vestibular-balance deficits immediately following head injury. This study uses a comprehensive battery of assessments to characterize auditory and vestibular function in 71 U.S. military service members with chronic symptoms following mild traumatic brain injury that did not resolve with traditional interventions. The majority of the study population reported hearing loss (70%) and recent vestibular symptoms (83%). Central auditory deficits were most prevalent, with 58% of participants failing the SCAN3:A screening test and 45% showing abnormal responses on auditory steady-state response testing presented at a suprathreshold intensity. Only 17% of the participants had abnormal hearing (⟩25 dB hearing loss) based on the pure-tone average. Objective vestibular testing supported significant deficits in this population, regardless of whether the participant self-reported active symptoms. Composite score on the Sensory Organization Test was lower than expected from normative data (mean 69.6 ±vestibular tests, vestibulo-ocular reflex, central auditory dysfunction, mild traumatic brain injury, post-concussive symptoms, hearing15.6). High abnormality rates were found in funduscopy torsion (58%), oculomotor assessments (49%), ocular and cervical vestibular evoked myogenic potentials (46% and 33%, respectively), and monothermal calorics (40%). It is recommended that a full peripheral and central auditory, oculomotor, and vestibular-balance evaluation be completed on military service members who have sustained head trauma.

Effects of Peripheral Vestibular Dysfunction on Dynamic Postural Stability Measured by the Functional Reach Test and Timed Up and Go Test.

PubMed

Nishi, Toshiko; Kamogashira, Teru; Fujimoto, Chisato; Kinoshita, Makoto; Egami, Naoya; Sugasawa, Keiko; Yamasoba, Tatsuya; Iwasaki, Shinichi

2017-06-01

To investigate the influence of vestibular function on dynamic postural stability assessed by the functional reach test (FRT) and the timed up and go test (TUG). Retrospective study. Tertiary referral center. The FRT and TUG were performed in 399 patients with dizziness. The effects of peripheral vestibular dysfunction assessed by the caloric test and cervical vestibular evoked myogenic potentials (cVEMPs) to air-conducted sound (500 Hz, tone burst) on the results of FRT and TUG were analyzed. Neither FRT nor TUG scores showed significant differences in relation to the results of the caloric test ( P > .3). The FRT scores in patients who showed abnormal cVEMP responses on both sides were significantly smaller than those in patients who showed normal cVEMP responses ( P < .01). The TUG scores in patients who showed abnormal cVEMP responses on both sides were significantly greater than those in patients who showed normal cVEMP responses ( P < .05). The vestibulo-spinal reflex mediated by the saccule and its afferents is one of the factors that influence the maintenance of dynamic postural stability as measured by FRT and TUG.

The evolution of concepts of vestibular peripheral information processing: toward the dynamic, adaptive, parallel processing macular model

NASA Technical Reports Server (NTRS)

Ross, Muriel D.

2003-01-01

In a letter to Robert Hooke, written on 5 February, 1675, Isaac Newton wrote "If I have seen further than certain other men it is by standing upon the shoulders of giants." In his context, Newton was referring to the work of Galileo and Kepler, who preceded him. However, every field has its own giants, those men and women who went before us and, often with few tools at their disposal, uncovered the facts that enabled later researchers to advance knowledge in a particular area. This review traces the history of the evolution of views from early giants in the field of vestibular research to modern concepts of vestibular organ organization and function. Emphasis will be placed on the mammalian maculae as peripheral processors of linear accelerations acting on the head. This review shows that early, correct findings were sometimes unfortunately disregarded, impeding later investigations into the structure and function of the vestibular organs. The central themes are that the macular organs are highly complex, dynamic, adaptive, distributed parallel processors of information, and that historical references can help us to understand our own place in advancing knowledge about their complicated structure and functions.

Waiting for the evidence: VEMP testing and the ability to differentiate utricular versus saccular function.

PubMed

Welgampola, Miriam S; Carey, John P

2010-08-01

The advent of cervical vestibular evoked myogenic potentials (CVEMPs) marked a milestone in clinical vestibular testing because they provided a simple means of assessing human otolith function. The availability of air-conducted (AC) sound and bone-conducted vibration (BCV) to evoke CVEMPs and development of a new technique of recording ocular vestibular-evoked myogenic potentials (OVEMPs) have increased the complexity of this simple test, yet extended its diagnostic capabilities. Here we highlight the evidence-based assumptions that guide interpretation of AC sound- and BCV-evoked VEMPs and the gaps in VEMP research thus far. Copyright (c) 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.

Bioinformatic Integration of Molecular Networks and Major Pathways Involved in Mice Cochlear and Vestibular Supporting Cells.

PubMed

Requena, Teresa; Gallego-Martinez, Alvaro; Lopez-Escamez, Jose A

2018-01-01

Background : Cochlear and vestibular epithelial non-hair cells (ENHCs) are the supporting elements of the cellular architecture in the organ of Corti and the vestibular neuroepithelium in the inner ear. Intercellular and cell-extracellular matrix interactions are essential to prevent an abnormal ion redistribution leading to hearing and vestibular loss. The aim of this study is to define the main pathways and molecular networks in the mouse ENHCs. Methods : We retrieved microarray and RNA-seq datasets from mouse epithelial sensory and non-sensory cells from gEAR portal (http://umgear.org/index.html) and obtained gene expression fold-change between ENHCs and non-epithelial cells (NECs) against HCs for each gene. Differentially expressed genes (DEG) with a log2 fold change between 1 and -1 were discarded. The remaining genes were selected to search for interactions using Ingenuity Pathway Analysis and STRING platform. Specific molecular networks for ENHCs in the cochlea and the vestibular organs were generated and significant pathways were identified. Results : Between 1723 and 1559 DEG were found in the mouse cochlear and vestibular tissues, respectively. Six main pathways showed enrichment in the supporting cells in both tissues: (1) "Inhibition of Matrix Metalloproteases"; (2) "Calcium Transport I"; (3) "Calcium Signaling"; (4) "Leukocyte Extravasation Signaling"; (5) "Signaling by Rho Family GTPases"; and (6) "Axonal Guidance Si". In the mouse cochlea, ENHCs showed a significant enrichment in 18 pathways highlighting "axonal guidance signaling (AGS)" ( p = 4.37 × 10 -8 ) and "RhoGDI Signaling" ( p = 3.31 × 10 -8 ). In the vestibular dataset, there were 20 enriched pathways in ENHCs, the most significant being "Leukocyte Extravasation Signaling" ( p = 8.71 × 10 -6 ), "Signaling by Rho Family GTPases" ( p = 1.20 × 10 -5 ) and "Calcium Signaling" ( p = 1.20 × 10 -5 ). Among the top ranked networks, the most biologically significant network contained the "auditory and vestibular system development and function" terms. We also found 108 genes showing tonotopic gene expression in the cochlear ENHCs. Conclusions : We have predicted the main pathways and molecular networks for ENHCs in the organ of Corti and vestibular neuroepithelium. These pathways will facilitate the design of molecular maps to select novel candidate genes for hearing or vestibular loss to conduct functional studies.

Convergence of excitatory and inhibitory hair cell transmitters shapes vestibular afferent responses.

PubMed

Holstein, Gay R; Rabbitt, Richard D; Martinelli, Giorgio P; Friedrich, Victor L; Boyle, Richard D; Highstein, Stephen M

2004-11-02

The vestibular semicircular canals respond to angular acceleration that is integrated to angular velocity by the biofluid mechanics of the canals and is the primary origin of afferent responses encoding velocity. Surprisingly, some afferents actually report angular acceleration. Our data indicate that hair-cell/afferent synapses introduce a mathematical derivative in these afferents that partially cancels the biomechanical integration and results in discharge rates encoding angular acceleration. We examined the role of convergent synaptic inputs from hair cells to this mathematical differentiation. A significant reduction in the order of the differentiation was observed for low-frequency stimuli after gamma-aminobutyric acid type B receptor antagonist administration. Results demonstrate that gamma-aminobutyric acid participates in shaping the temporal dynamics of afferent responses.

Determine Optimal Stimulus Amplitude for Using Vestibular Stochastic Stimulation to Improve Balance Function

NASA Technical Reports Server (NTRS)

Goel, R.; Kofman, I.; DeDios, Y. E.; Jeevarajan, J.; Stepanyan, V.; Nair, M.; Congdon, S.; Fregia, M.; Cohen, H.; Bloomberg, J.J.;

Vestibular vertigo and comorbid cognitive and psychiatric impairment: the 2008 National Health Interview Survey.

PubMed

Bigelow, Robin T; Semenov, Yevgeniy R; du Lac, Sascha; Hoffman, Howard J; Agrawal, Yuri

2016-04-01

Patients with vestibular disease have been observed to have concomitant cognitive and psychiatric dysfunction. We evaluated the association between vestibular vertigo, cognitive impairment and psychiatric conditions in a nationally representative sample of US adults. We performed a cross-sectional analysis using the 2008 National Health Interview Survey (NHIS), which included a Balance and Dizziness Supplement, and questions about cognitive function and psychiatric comorbidity. We evaluated the association between vestibular vertigo, cognitive impairment (memory loss, difficulty concentrating, confusion) and psychiatric diagnoses (depression, anxiety and panic disorder). We observed an 8.4% 1-year prevalence of vestibular vertigo among US adults. In adjusted analyses, individuals with vestibular vertigo had an eightfold increased odds of 'serious difficulty concentrating or remembering' (OR 8.3, 95% CI 4.8 to 14.6) and a fourfold increased odds of activity limitation due to difficulty remembering or confusion (OR 3.9, 95% CI 3.1 to 5.0) relative to the rest of the US adults. Individuals with vestibular vertigo also had a threefold increased odds of depression (OR 3.4, 95% CI 2.9 to 3.9), anxiety (OR 3.2, 95% CI 2.8 to 3.6) and panic disorder (OR 3.4, 95% CI 2.9 to 4.0). Our findings indicate that vestibular impairment is associated with increased risk of cognitive and psychiatric comorbidity. The vestibular system is anatomically connected with widespread regions of the cerebral cortex, hippocampus and amygdala. Loss of vestibular inputs may lead to impairment of these cognitive and affective circuits. Further longitudinal research is required to determine if these associations are causal. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

The Central Nervous Connections Involved in the Vomiting Reflex

NASA Technical Reports Server (NTRS)

Brizzee, K. R.; Mehler, W. R.

1986-01-01

The vomiting reflex may be elicited by a number of different types or classes of stimuli involving many varieties of receptor structures and considerable diversity in afferent pathways and central connections. Central relay or mediating structures thus may vary widely according to the type of initial emetic stimulus. The emetic circuits which have been most completely delineated to date are probably those in which the Chemoreceptor Trigger Zone (CTZ) in the Area Postrema (AP) functions as a key mediating structure. Even in this system, however, there are large gaps in our knowledge of the nerve tracts and central nervous connections involved. Knowledge of most other emetic circuits subserving the emetic reflex resulting from many diverse types of stimuli such, for example, as emotional stress (e.g. psychogenic vomiting, Wruble et al. 1982), pain (e.g. testicular trauma), and chemical or mechanical irritation of the gastrointestinal tract or urinary tract is quite incomplete at this time, thus precluding any very adequate description of their central connections at present. One physiological system, however, which has received considerable attention recently in relation to the vomiting reflex elicited by motion stimuli is the vestibular system. Due to the paucity of data on central nervous connections of several or the non-vestibular types of emetic stimuli cited above, we will devote most of our attention in this brief review to the central connections of the vestibular system which seem likely to be involved in the vomiting response to motion stimuli. However, the latter part of the review will be concerned with the concept of the reticular vomiting centre in relation to the ParviCellular Reticular Formation (PCRF), and will thus probably pertain to all of the many classes of emetic stimuli since it will address the question of the final common emetic pathway.

Neuroactive substances in the human vestibular end organs.

PubMed

Usami, S; Matsubara, A; Shinkawa, H; Matsunaga, T; Kanzaki, J

1995-01-01

In order to evaluate the involvement of neuroactive substances in the human vestibular periphery, the immunocytochemical distribution of substance P (SP), calcitonin gene-related peptide (CGRP), and choline acetyltransferase (ChAT) was examined. SP-like immunoreactivity (LI) was present around and beneath sensory hair cells, probably corresponding to their afferent nerve endings. SP-LI was found predominantly in subpopulations of the primary afferents distributed in the peripheral region of the end organs. ChAT-LI and CGRP-LI were found throughout as small puncta below the hair cell layer, probably corresponding to efferent endings. The present results indicate that these neuroactive substances, previously described in animals, are also distributed in the human vestibular periphery, and almost certainly contribute to human vestibular function.

Novel compound heterozygous mutations in the GPR98 (USH2C) gene identified by whole exome sequencing in a Moroccan deaf family.

PubMed

Bousfiha, Amale; Bakhchane, Amina; Charoute, Hicham; Detsouli, Mustapha; Rouba, Hassan; Charif, Majida; Lenaers, Guy; Barakat, Abdelhamid

2017-10-01

In the present work, we identified two novel compound heterozygote mutations in the GPR98 (G protein-coupled receptor 98) gene causing Usher syndrome. Whole-exome sequencing was performed to study the genetic causes of Usher syndrome in a Moroccan family with three affected siblings. We identify two novel compound heterozygote mutations (c.1054C > A, c.16544delT) in the GPR98 gene in the three affected siblings carrying post-linguale bilateral moderate hearing loss with normal vestibular functions and before installing visual disturbances. This is the first time that mutations in the GPR98 gene are described in the Moroccan deaf patients.

Astronauts Conrad and Kerwin - Human Vestibular Function Experiment - JSC

NASA Image and Video Library

1973-01-01

S73-20678 (1 March 1973) --- Astronaut Charles Conrad Jr., commander of the first manned Skylab mission, checks out the Human Vestibular Function, Experiment M131, during Skylab training at Johnson Space Center. Scientist-astronaut Joseph P. Kerwin, science pilot of the mission, goes over a checklist. The two men are in the work and experiments compartment of the crew quarters of the Skylab Orbital Workshop (OWS) trainer at JSC. Photo credit: NASA

In silico Analysis of 2085 Clones from a Normalized Rat Vestibular Periphery 3′ cDNA Library

PubMed Central

Roche, Joseph P.; Cioffi, Joseph A.; Kwitek, Anne E.; Erbe, Christy B.; Popper, Paul

2005-01-01

The inserts from 2400 cDNA clones isolated from a normalized Rattus norvegicus vestibular periphery cDNA library were sequenced and characterized. The Wackym-Soares vestibular 3′ cDNA library was constructed from the saccular and utricular maculae, the ampullae of all three semicircular canals and Scarpa's ganglia containing the somata of the primary afferent neurons, microdissected from 104 male and female rats. The inserts from 2400 randomly selected clones were sequenced from the 5′ end. Each sequence was analyzed using the BLAST algorithm compared to the Genbank nonredundant, rat genome, mouse genome and human genome databases to search for high homology alignments. Of the initial 2400 clones, 315 (13%) were found to be of poor quality and did not yield useful information, and therefore were eliminated from the analysis. Of the remaining 2085 sequences, 918 (44%) were found to represent 758 unique genes having useful annotations that were identified in databases within the public domain or in the published literature; these sequences were designated as known characterized sequences. 1141 sequences (55%) aligned with 1011 unique sequences had no useful annotations and were designated as known but uncharacterized sequences. Of the remaining 26 sequences (1%), 24 aligned with rat genomic sequences, but none matched previously described rat expressed sequence tags or mRNAs. No significant alignment to the rat or human genomic sequences could be found for the remaining 2 sequences. Of the 2085 sequences analyzed, 86% were singletons. The known, characterized sequences were analyzed with the FatiGO online data-mining tool (http://fatigo.bioinfo.cnio.es/) to identify level 5 biological process gene ontology (GO) terms for each alignment and to group alignments with similar or identical GO terms. Numerous genes were identified that have not been previously shown to be expressed in the vestibular system. Further characterization of the novel cDNA sequences may lead to the identification of genes with vestibular-specific functions. Continued analysis of the rat vestibular periphery transcriptome should provide new insights into vestibular function and generate new hypotheses. Physiological studies are necessary to further elucidate the roles of the identified genes and novel sequences in vestibular function. PMID:16103642

Optimal Stimulus Amplitude for Vestibular Stochastic Stimulation to Improve Sensorimotor Function

NASA Technical Reports Server (NTRS)

Goel, R.; Kofman, I.; DeDios, Y. E.; Jeevarajan, J.; Stepanyan, V.; Nair, M.; Congdon, S.; Fregia, M.; Cohen, H.; Bloomberg, J. J.;

NASA Workshop on Animal Gravity-Sensing Systems

NASA Technical Reports Server (NTRS)

Corcoran, M. L. (Editor)

1986-01-01

The opportunity for space flight has brought about the need for well-planned research programs that recognize the significance of space flight as a scientific research tool for advancing knowledge of life on Earth, and that utilize each flight opportunity to its fullest. For the first time in history, gravity can be almost completely eliminated. Thus, studies can be undertaken that will help to elucidate the importance of gravity to the normal functioning of living organisms, and to determine the effects microgravity may have on an organism. This workshop was convened to organize a plan for space research on animal gravity-sensing systems and the role that gravity plays in the development and normal functioning of these systems. Scientists working in the field of animal gravity-sensing systems use a wide variety of organisms in their research. The workshop presentations dealt with topics which ranged from the indirect gravity receptor of the water flea, Daphnia (whose antennal setae apparently act as current-sensing receptors as the animal moves up and down in water), through specialized statocyst structures found in jellyfish and gastropods, to the more complex vestibular systems that are characteristic of amphibians, avians, and mammals.

Evidence of a gustatory-vestibular pathway for protein transport.

PubMed

Gacek, Richard; Lyon, Michael J

2010-02-01

To demonstrate anatomically a pathway for protein transport from the palate to the vestibular system. The vestibulofacial anastomosis and associated ganglion cells were identified in a collection of 160 horizontally sectioned human temporal bones that had been stained with hematoxylin and eosin. Wheat germ agglutinin-horseradish peroxidase (HRP) was applied to the greater superficial petrosal nerve in 4 Sprague-Dawley rats. After 30 hours, the rats were killed by intracardiac perfusion, and the seventh and eighth nerves with adjacent brainstem removed. Frozen sections cut at 30 mum through this block were then reacted for HRP, counterstained with neutral red, and mounted on slides for examination in the light microscope. Thirty-two of the 160 human temporal bones contained sections through the vestibulofacial anastomosis and its ganglion. In all cases, the ganglion was incorporated into the vestibular ganglion (VG) adjacent to the nervus intermedius. In all 4 experimental rats, HRP reaction product labeled a small number of ganglion cells in the VG adjacent to the nervus intermedius and facial nerve. These observations support the presence of a pathway from receptors in the palate to the VG.

Supporting cells remove and replace sensory receptor hair cells in a balance organ of adult mice

PubMed Central

Bucks, Stephanie A; Cox, Brandon C; Vlosich, Brittany A; Manning, James P; Nguyen, Tot B; Stone, Jennifer S

2017-01-01

Vestibular hair cells in the inner ear encode head movements and mediate the sense of balance. These cells undergo cell death and replacement (turnover) throughout life in non-mammalian vertebrates. However, there is no definitive evidence that this process occurs in mammals. We used fate-mapping and other methods to demonstrate that utricular type II vestibular hair cells undergo turnover in adult mice under normal conditions. We found that supporting cells phagocytose both type I and II hair cells. Plp1-CreERT2-expressing supporting cells replace type II hair cells. Type I hair cells are not restored by Plp1-CreERT2-expressing supporting cells or by Atoh1-CreERTM-expressing type II hair cells. Destruction of hair cells causes supporting cells to generate 6 times as many type II hair cells compared to normal conditions. These findings expand our understanding of sensorineural plasticity in adult vestibular organs and further elucidate the roles that supporting cells serve during homeostasis and after injury. DOI: http://dx.doi.org/10.7554/eLife.18128.001 PMID:28263708

Objective vestibular testing of children with dizziness and balance complaints following sports-related concussions.

PubMed

Zhou, Guangwei; Brodsky, Jacob R

2015-06-01

To conduct objective assessment of children with balance and vestibular complaints following sports-related concussions and identify the underlying deficits by analyzing laboratory test outcomes. Case series with chart review. Pediatric tertiary care facility. Medical records were reviewed of 42 pediatric patients with balance and/or vestibular complaints following sports-related concussions who underwent comprehensive laboratory testing on their balance and vestibular function. Patients' characteristics were summarized and results analyzed. More than 90% of the children with protracted dizziness or imbalance following sports-related concussion had at least 1 abnormal finding from the comprehensive balance and vestibular evaluation. The most frequent deficit was found in dynamic visual acuity test, followed by Sensory Organization Test and rotational test. Patient's balance problem associated with concussion seemed to be primarily instigated by vestibular dysfunction. Furthermore, semicircular canal dysfunction was involved more often than dysfunction of otolith organs. Yet, <10% of the children experienced a hearing loss following sports-related concussion. Vestibular impairment is common among children with protracted dizziness or imbalance following sports-related concussion. Our study demonstrated that proper and thorough evaluation is imperative to identify these underlying deficits and laboratory tests were helpful in the diagnosis and recommendation of following rehabilitations. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

The role of the vestibular system in manual target localization

NASA Technical Reports Server (NTRS)

Barry, Susan R.; Mueller, S. Alyssa

1995-01-01

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.

The sensory-motor theory of rhythm and beat induction 20 years on: a new synthesis and future perspectives

PubMed Central

Todd, Neil P. M.; Lee, Christopher S.

2015-01-01

Some 20 years ago Todd and colleagues proposed that rhythm perception is mediated by the conjunction of a sensory representation of the auditory input and a motor representation of the body (Todd, 1994a, 1995), and that a sense of motion from sound is mediated by the vestibular system (Todd, 1992a, 1993b). These ideas were developed into a sensory-motor theory of rhythm and beat induction (Todd et al., 1999). A neurological substrate was proposed which might form the biological basis of the theory (Todd et al., 2002). The theory was implemented as a computational model and a number of experiments conducted to test it. In the following time there have been several key developments. One is the demonstration that the vestibular system is primal to rhythm perception, and in related work several experiments have provided further evidence that rhythm perception is body dependent. Another is independent advances in imaging, which have revealed the brain areas associated with both vestibular processing and rhythm perception. A third is the finding that vestibular receptors contribute to auditory evoked potentials (Todd et al., 2014a,b). These behavioral and neurobiological developments demand a theoretical overview which could provide a new synthesis over the domain of rhythm perception. In this paper we suggest four propositions as the basis for such a synthesis. (1) Rhythm perception is a form of vestibular perception; (2) Rhythm perception evokes both external and internal guidance of somatotopic representations; (3) A link from the limbic system to the internal guidance pathway mediates the “dance habit”; (4) The vestibular reward mechanism is innate. The new synthesis provides an explanation for a number of phenomena not often considered by rhythm researchers. We discuss these along with possible computational implementations and alternative models and propose a number of new directions for future research. PMID:26379522

The sensory-motor theory of rhythm and beat induction 20 years on: a new synthesis and future perspectives.

PubMed

Todd, Neil P M; Lee, Christopher S

2015-01-01

Some 20 years ago Todd and colleagues proposed that rhythm perception is mediated by the conjunction of a sensory representation of the auditory input and a motor representation of the body (Todd, 1994a, 1995), and that a sense of motion from sound is mediated by the vestibular system (Todd, 1992a, 1993b). These ideas were developed into a sensory-motor theory of rhythm and beat induction (Todd et al., 1999). A neurological substrate was proposed which might form the biological basis of the theory (Todd et al., 2002). The theory was implemented as a computational model and a number of experiments conducted to test it. In the following time there have been several key developments. One is the demonstration that the vestibular system is primal to rhythm perception, and in related work several experiments have provided further evidence that rhythm perception is body dependent. Another is independent advances in imaging, which have revealed the brain areas associated with both vestibular processing and rhythm perception. A third is the finding that vestibular receptors contribute to auditory evoked potentials (Todd et al., 2014a,b). These behavioral and neurobiological developments demand a theoretical overview which could provide a new synthesis over the domain of rhythm perception. In this paper we suggest four propositions as the basis for such a synthesis. (1) Rhythm perception is a form of vestibular perception; (2) Rhythm perception evokes both external and internal guidance of somatotopic representations; (3) A link from the limbic system to the internal guidance pathway mediates the "dance habit"; (4) The vestibular reward mechanism is innate. The new synthesis provides an explanation for a number of phenomena not often considered by rhythm researchers. We discuss these along with possible computational implementations and alternative models and propose a number of new directions for future research.

Usher syndrome type III can mimic other types of Usher syndrome.

PubMed

Pennings, Ronald J E; Fields, Randall R; Huygen, Patrick L M; Deutman, August F; Kimberling, William J; Cremers, Cor W R J

2003-06-01

Clinical and genetic characteristics are presented of 2 patients from a Dutch Usher syndrome type III family who have a new homozygous USH3 gene mutation: 149-152delCAGG + insTGTCCAAT. One individual (IV:1) is profoundly hearing impaired and has normal vestibular function and retinitis punctata albescens (RPA). The other individual is also profoundly hearing impaired, but has well-developed speech, vestibular areflexia, and retinitis pigmentosa sine pigmento (RPSP). These findings suggest that Usher syndrome type III can be clinically misdiagnosed as either Usher type I or II; that Usher syndrome patients who are profoundly hearing impaired and have normal vestibular function should be tested for USH3 mutations; and that RPA and RPSP can occur as fundoscopic manifestations of pigmentary retinopathy in Usher syndrome.

Vestibular Function Measurement Devices

PubMed Central

Miles, Richard D.; Zapala, David A.

2015-01-01

Vestibular function laboratories utilize a multitude of diagnostic instruments to evaluate a dizzy patient. Caloric irrigators, oculomotor stimuli, and rotational chairs produce a stimulus whose accuracy is required for the patient response to be accurate. Careful attention to everything from cleanliness of equipment to threshold adjustments determine on a daily basis if patient data are going to be correct and useful. Instrumentation specifications that change with time such as speed and temperature must periodically be checked using calibrated instruments. PMID:27516710

Fate-mapping the mammalian hindbrain: segmental origins of vestibular projection neurons assessed using rhombomere-specific Hoxa2 enhancer elements in the mouse embryo.

PubMed

Pasqualetti, Massimo; Díaz, Carmen; Renaud, Jean-Sébastien; Rijli, Filippo M; Glover, Joel C

2007-09-05

As a step toward generating a fate map of identified neuron populations in the mammalian hindbrain, we assessed the contributions of individual rhombomeres to the vestibular nuclear complex, a major sensorimotor area that spans the entire rhombencephalon. Transgenic mice harboring either the lacZ or the enhanced green fluorescent protein reporter genes under the transcriptional control of rhombomere-specific Hoxa2 enhancer elements were used to visualize rhombomere-derived domains. We labeled functionally identifiable vestibular projection neuron groups retrogradely with conjugated dextran-amines at successive embryonic stages and obtained developmental fate maps through direct comparison with the rhombomere-derived domains in the same embryos. The fate maps show that each vestibular neuron group derives from a unique rostrocaudal domain that is relatively stable developmentally, suggesting that anteroposterior migration is not a major contributor to the rostrocaudal patterning of the vestibular system. Most of the groups are multisegmental in origin, and each rhombomere is fated to give rise to two or more vestibular projection neuron types, in a complex pattern that is not segmentally iterated. Comparison with studies in the chicken embryo shows that the rostrocaudal patterning of identified vestibular projection neuron groups is generally well conserved between avians and mammalians but that significant species-specific differences exist in the rostrocaudal limits of particular groups. This mammalian hindbrain fate map can be used as the basis for targeting genetic manipulation to specific subpopulations of vestibular projection neurons.

Efferent-Mediated Responses in Vestibular Nerve Afferents of the Alert Macaque

PubMed Central

Sadeghi, Soroush G.; Goldberg, Jay M.; Minor, Lloyd B.; Cullen, Kathleen E.

2009-01-01

The peripheral vestibular organs have long been known to receive a bilateral efferent innervation from the brain stem. However, the functional role of the efferent vestibular system has remained elusive. In this study, we investigated efferent-mediated responses in vestibular afferents of alert behaving primates (macaque monkey). We found that efferent-mediated rotational responses could be obtained from vestibular nerve fibers innervating the semicircular canals after conventional afferent responses were nulled by placing the corresponding canal plane orthogonal to the plane of motion. Responses were type III, i.e., excitatory for rotational velocity trapezoids (peak velocity, 320°/s) in both directions of rotation, consistent with those previously reported in the decerebrate chinchilla. Responses consisted of both fast and slow components and were larger in irregular (∼10 spikes/s) than in regular afferents (∼2 spikes/s). Following unilateral labyrinthectomy (UL) on the side opposite the recording site, similar responses were obtained. To confirm the vestibular source of the efferent-mediated responses, the ipsilateral horizontal and posterior canals were plugged following the UL. Responses to high-velocity rotations were drastically reduced when the superior canal (SC), the only intact canal, was in its null position, compared with when the SC was pitched 50° upward from the null position. Our findings show that vestibular afferents in alert primates show efferent-mediated responses that are related to the discharge regularity of the afferent, are of vestibular origin, and can be the result of both afferent excitation and inhibition. PMID:19091917

Efferent-mediated responses in vestibular nerve afferents of the alert macaque.

PubMed

Sadeghi, Soroush G; Goldberg, Jay M; Minor, Lloyd B; Cullen, Kathleen E

2009-02-01

The peripheral vestibular organs have long been known to receive a bilateral efferent innervation from the brain stem. However, the functional role of the efferent vestibular system has remained elusive. In this study, we investigated efferent-mediated responses in vestibular afferents of alert behaving primates (macaque monkey). We found that efferent-mediated rotational responses could be obtained from vestibular nerve fibers innervating the semicircular canals after conventional afferent responses were nulled by placing the corresponding canal plane orthogonal to the plane of motion. Responses were type III, i.e., excitatory for rotational velocity trapezoids (peak velocity, 320 degrees/s) in both directions of rotation, consistent with those previously reported in the decerebrate chinchilla. Responses consisted of both fast and slow components and were larger in irregular (approximately 10 spikes/s) than in regular afferents (approximately 2 spikes/s). Following unilateral labyrinthectomy (UL) on the side opposite the recording site, similar responses were obtained. To confirm the vestibular source of the efferent-mediated responses, the ipsilateral horizontal and posterior canals were plugged following the UL. Responses to high-velocity rotations were drastically reduced when the superior canal (SC), the only intact canal, was in its null position, compared with when the SC was pitched 50 degrees upward from the null position. Our findings show that vestibular afferents in alert primates show efferent-mediated responses that are related to the discharge regularity of the afferent, are of vestibular origin, and can be the result of both afferent excitation and inhibition.

Prediction of Balance Compensation After Vestibular Schwannoma Surgery.

PubMed

Parietti-Winkler, Cécile; Lion, Alexis; Frère, Julien; Perrin, Philippe P; Beurton, Renaud; Gauchard, Gérome C

2016-06-01

Background Balance compensation after vestibular schwannoma (VS) surgery is under the influence of specific preoperative patient and tumor characteristics. Objective To prospectively identify potential prognostic factors for balance recovery, we compared the respective influence of these preoperative characteristics on balance compensation after VS surgery. Methods In 50 patients scheduled for VS surgical ablation, we measured postural control before surgery (BS), 8 (AS8) days after, and 90 (AS90) days after surgery. Based on factors found previously in the literature, we evaluated age, body mass index and preoperative physical activity (PA), tumor grade, vestibular status, and preference for visual cues to control balance as potential prognostic factors using stepwise multiple regression models. Results An asymmetric vestibular function was the sole significant explanatory factor for impaired balance performance BS, whereas the preoperative PA alone significantly contributed to higher performance at AS8. An evaluation of patients' balance recovery over time showed that PA and vestibular status were the 2 significant predictive factors for short-term postural compensation (BS to AS8), whereas none of these preoperative factors was significantly predictive for medium-term postoperative postural recovery (AS8 to AS90). Conclusions We identified specific preoperative patient and vestibular function characteristics that may predict postoperative balance recovery after VS surgery. Better preoperative characterization of these factors in each patient could inform more personalized presurgical and postsurgical management, leading to a better, more rapid balance recovery, earlier return to normal daily activities and work, improved quality of life, and reduced medical and societal costs. © The Author(s) 2015.

Role of orientation reference selection in motion sickness, supplement 2S

NASA Technical Reports Server (NTRS)

Peterka, Robert J.; Black, F. Owen

1987-01-01

Previous experiments with moving platform posturography have shown that different people have varying abilities to resolve conflicts among vestibular, visual, and proprioceptive sensory signals. The conceptual basis of the present proposal hinges on the similarities between the space motion sickness problem and the sensory orientation reference selection problems associated with benign paroxysmal positional vertigo (BPPV) syndrome. These similarities include both etiology related to abnormal vertical canal-otolith function, and motion sickness initiating events provoked by pitch and roll head movements. The objectives are to explore and quantify the orientation reference selection abilities of subjects and the relation of this selection to motion sickness in humans. The overall objectives are to determine: if motion sickness susceptibility is related to sensory orientation reference selection abilities of subjects; if abnormal vertical canal-otolith function is the source of abnormal posture control strategies and if it can be quantified by vestibular and oculomotor reflex measurements, and if it can be quantified by vestibular and oculomotor reflex measurements; and quantifiable measures of perception of vestibular and visual motion cues can be related to motion sickness susceptibility and to orientation reference selection ability.

[Built-in emergency brake in the balance system. Animal experiment research shows that a hierarchy of mechanisms compensate after acute peripheral vestibular decline].

PubMed

Magnusson, Anna K; Tham, Richard

A sudden unilateral loss of peripheral vestibular input results in the onset of acute dizziness and imbalance associated with spontaneous nystagmus, postural instability and nausea. Fortunately, these symptoms ameliorate rapidly, even without treatment, due to central nervous plastic changes which are collectively termed "vestibular compensation". This concept has become a widely accepted research model for studying lesion-induced plasticity. Recent research has dealt in particular with the plasticity of the medial vestibular nuclei that mediate the horizontal vestibulo-ocular reflex. Studies range from a cellular level in vitro to a functional level in vivo. Taken together, results from such studies have contributed greatly to what is known of vestibular compensation today. This article summarises evidence for several plasticity mechanisms that drive the recovery of spontaneous nystagmus, one of which is dependent on an endocrine stress-response. In the long run, such knowledge might influence the management and treatment of patients with balance disorders.

Health‐related quality of life and economic burden of vestibular loss in older adults

PubMed Central

Agrawal, Yuri; Semenov, Yevgeniy R.

2017-01-01

Objectives Vestibular loss is a debilitating condition, and despite its high prevalence in older adults, the quality of life (QoL) burden of vestibular loss in older individuals has not been well‐studied. This report quantifies the impact on overall QoL and identifies domains of health most affected. We hypothesize vestibular loss will be associated with impairment in diverse domains of health‐related QoL. Study Design Prospective, case‐control study. Methods A convenience sample of 27 patients age ≥60 years with vestibular physiologic loss was recruited from an academic neurotology clinic. The patients did not have any identifiable cause of their vestibular loss other than aging. The convenience sample was compared to an age‐matched cross‐sectional sample of the general US population (n = 1266). The main outcome was QoL measured by the Ontario Health Utilities Index Mark III (HUI3). Results Compared to the general population, patients with vestibular loss had significantly lower overall unadjusted HUI3 scores (−0.32, p < 0.001). Multivariate regression analysis showed vestibular loss was significantly associated with poorer performance in vision (−0.11 p < 0.0001), speech (−0.15, p < 0.0001), dexterity (−0.13, p < 0.0001), and emotion (−0.07, p = 0.0065). Adjusted aggregate HUI3 was also significantly lower for vestibular loss (−0.15, p = 0.0105). These QoL decrements resulted in an average loss of 1.30 Quality‐Adjusted Life Years (QALYs). When using a $50,000/QALY willingness‐to‐pay threshold, vestibular loss was associated with a $64,929 lifetime economic burden per affected older adult, resulting in a total lifetime societal burden of $227 billion for the US population ≥60 years of age. Conclusions Loss of vestibular function with aging significantly decreases quality of life across multiple domains of well‐being. These QoL reductions are responsible for heavy societal economic burdens of vestibular loss, which reveal potential benefits of prompt diagnosis and treatment of this condition. Level of Evidence 3 PMID:29492463

Precision contact of the fingertip reduces postural sway of individuals with bilateral vestibular loss

NASA Technical Reports Server (NTRS)

Lackner, J. R.; DiZio, P.; Jeka, J.; Horak, F.; Krebs, D.; Rabin, E.

1999-01-01

Contact of the hand with a stationary surface attenuates postural sway in normal individuals even when the level of force applied is mechanically inadequate to dampen body motion. We studied whether subjects without vestibular function would be able to substitute contact cues from the hand for their lost labyrinthine function and be able to balance as well as normal subjects in the dark without finger contact. We also studied the relative contribution of sight of the test chamber to the two groups. Subjects attempted to maintain a tandem Romberg stance for 25 s under three levels of fingertip contact: no contact; light-touch contact, up to 1 N (approximately 100 g) force; and unrestricted contact force. Both eyes open and eyes closed conditions were evaluated. Without contact, none of the vestibular loss subjects could stand for more than a few seconds in the dark without falling; all the normals could. The vestibular loss subjects were significantly more stable in the dark with light touch of the index finger than the normal subjects in the dark without touch. They also swayed less in the dark with light touch than when permitted sight of the test chamber without touch, and less with sight and touch than just sight. The normal subjects swayed less in the dark with touch than without, and less with sight and touch than sight alone. These findings show that during quiet stance light touch of the index finger with a stationary surface can be as effective or even more so than vestibular function for minimizing postural sway.

Sleep and vestibular adaptation: implications for function in microgravity

NASA Technical Reports Server (NTRS)

Hobson, J. A.; Stickgold, R.; Pace-Schott, E. F.; Leslie, K. R.

1998-01-01

Optimal human performance depends upon integrated sensorimotor and cognitive functions, both of which are known to be exquisitely sensitive to loss of sleep. Under the microgravity conditions of space flight, adaptation of both sensorimotor (especially vestibular) and cognitive functions (especially orientation) must occur quickly--and be maintained--despite any concurrent disruptions of sleep that may be caused by microgravity itself, or by the uncomfortable sleeping conditions of the spacecraft. It is the three-way interaction between sleep quality, general work efficiency, and sensorimotor integration that is the subject of this paper and the focus of new work in our laboratory. To record sleep under field conditions including microgravity, we utilize a novel system called the Nightcap that we have developed and extensively tested on normal and sleep-disordered subjects. To perturb the vestibular system in ground-based studies, we utilize a variety of experimental conditions including optokinetic stimulation and both minifying and reversing goggle paradigms that have been extensively studied in relation to plasticity of the vestibulo-ocular reflex. Using these techniques we will test the hypothesis that vestibular adaptation both provokes and is enhanced by REM sleep under both ground-based and space conditions. In this paper we describe preliminary results of some of our studies.

[Effects of acute infrasound exposure on vestibular and auditory functions and the ultrastructural changes of inner ear in the guinea pig].

PubMed

Feng, B; Jiang, S; Yang, W; Han, D; Zhang, S

2001-02-01

To define the effects of acute infrasound exposure on vestibular and auditory functions and the ultrastructural changes of inner ear in guinea pigs. The animals involved in the study were exposed to 8 Hz infrasound at 135dB SPL for 90 minutes in a reverberant chamber. The sinusoidal pendular test (SPT), auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) were respectively detected pre-exposure and at 0(within 2 hrs), 2 and 5 day after exposure. The ultrastructures of the inner ear were observed by scanning electron microscopy. The slow-phase velocity and the frequency of the vestibular nystagmus elicited by sinusoidal pendular test (SPT) declined slightly following infrasound exposure, but the changes were not significant (P > 0.05). No differences in the ABR thresholds, the latencies and the interval peak latencies of I, III, V waves were found between the normal and the experimental groups, and among experimental groups. The amplitudes of DPOAE at any frequency declined remarkably in all experimental groups. The ultrastructures of the inner ear were damaged to different extent. Infrasound could transiently depress the excitability of the vestibular end-organs, decrease the function of OHC in the organ of Corti and cause damage to the inner ear of guinea pigs.

Practice guideline: Cervical and ocular vestibular evoked myogenic potential testing: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology.

PubMed

Fife, Terry D; Colebatch, James G; Kerber, Kevin A; Brantberg, Krister; Strupp, Michael; Lee, Hyung; Walker, Mark F; Ashman, Eric; Fletcher, Jeffrey; Callaghan, Brian; Gloss, David S

2017-11-28

To systematically review the evidence and make recommendations with regard to diagnostic utility of cervical and ocular vestibular evoked myogenic potentials (cVEMP and oVEMP, respectively). Four questions were asked: Does cVEMP accurately identify superior canal dehiscence syndrome (SCDS)? Does oVEMP accurately identify SCDS? For suspected vestibular symptoms, does cVEMP/oVEMP accurately identify vestibular dysfunction related to the saccule/utricle? For vestibular symptoms, does cVEMP/oVEMP accurately and substantively aid diagnosis of any specific vestibular disorder besides SCDS? The guideline panel identified and classified relevant published studies (January 1980-December 2016) according to the 2004 American Academy of Neurology process. Level C positive: Clinicians may use cVEMP stimulus threshold values to distinguish SCDS from controls (2 Class III studies) (sensitivity 86%-91%, specificity 90%-96%). Corrected cVEMP amplitude may be used to distinguish SCDS from controls (2 Class III studies) (sensitivity 100%, specificity 93%). Clinicians may use oVEMP amplitude to distinguish SCDS from normal controls (3 Class III studies) (sensitivity 77%-100%, specificity 98%-100%). oVEMP threshold may be used to aid in distinguishing SCDS from controls (3 Class III studies) (sensitivity 70%-100%, specificity 77%-100%). Level U: Evidence is insufficient to determine whether cVEMP and oVEMP can accurately identify vestibular function specifically related to the saccule/utricle, or whether cVEMP or oVEMP is useful in diagnosing vestibular neuritis or Ménière disease. Level C negative: It has not been demonstrated that cVEMP substantively aids in diagnosing benign paroxysmal positional vertigo, or that cVEMP or oVEMP aids in diagnosing/managing vestibular migraine. © 2017 American Academy of Neurology.

Outcome analysis of individualized vestibular rehabilitation protocols

NASA Technical Reports Server (NTRS)

Black, F. O.; Angel, C. R.; Pesznecker, S. C.; Gianna, C.

2000-01-01

OBJECTIVE: To determine the outcome of vestibular rehabilitation protocols in subjects with peripheral vestibular disorders compared with normal and abnormal control subjects. STUDY DESIGN: Prospective study using repeated measure, matched control design. Subjects were solicited consecutively according to these criteria: vestibular disorder subjects who had abnormal results of computerized dynamic posturography (CDP) sensory organization tests (SOTs) 5 and 6 and underwent rehabilitation; vestibular disorder subjects who had abnormal results of SOTs 5 and 6 and did not undergo rehabilitation; and normal subjects (normal SOTs). SETTING: Tertiary neurotology clinic. SUBJECTS: Men and women over age 18 with chronic vestibular disorders and chief complaints of unsteadiness, imbalance, and/or motion intolerance, and normal subjects. INTERVENTIONS: Pre- and post-rehabilitation assessment included CDP, vestibular disability, and activities of daily living questionnaires. Individualized rehabilitation plans were designed and implemented to address the subject's specific complaints and functional deficits. Supervised sessions were held at weekly intervals, and self-administered programs were devised for daily home use. MAIN OUTCOME MEASURES: CDP composite and SOT scores, number of falls on CDP, and self-assessment questionnaire results. RESULTS: Subjects who underwent rehabilitation (Group A) showed statistically significant improvements in SOTs, overall composite score, and reduction in falls compared with abnormal (Group B) control groups. Group A's performances after rehabilitation were not significantly different from those of normal subjects (Group C) in SOTs 3 through 6, and close to normal on SOTs 1 and 2. Subjects in Group A also reported statistically significant symptomatic improvement. CONCLUSIONS: Outcome measures of vestibular protocol physical therapy confirmed objective and subjective improvement in subjects with chronic peripheral vestibular disorders. These findings support results reported by other investigators.

Diversity of head shaking nystagmus in peripheral vestibular disease.

PubMed

Kim, Min-Beom; Huh, Se Hyung; Ban, Jae Ho

2012-06-01

To evaluate the characteristics of head shaking nystagmus in various peripheral vestibular diseases. Retrospective case series. Tertiary referral center. Data of 235 patients with peripheral vestibular diseases including vestibular neuritis, Ménière's disease, and benign paroxysmal positional vertigo, were retrospectively analyzed. All subjects presented between August 2009 and July 2010. Patients were tested for vestibular function including head shaking nystagmus and caloric information. Regarding vestibular neuritis, all tests were again performed during the 1-month follow-up. Head shaking nystagmus was classified as monophasic or biphasic and, according to the affected ear, was divided as ipsilesional or contralesional. Of the 235 patients, 87 patients revealed positive head shaking nystagmus. According to each disease, positive rates of head shaking nystagmus were as follows: 35 (100%) of 35 cases of vestibular neuritis, 11 (68.8%) of 16 cases of Ménière's disease, and 41 (22.2%) of 184 cases of benign paroxysmal positional vertigo. All cases of vestibular neuritis initially presented as a monophasic, contralesional beating, head shaking nystagmus. However, 1 month after first visit, the direction of nystagmus was changed to biphasic (contralesional first then ipsilesional beating) in 25 cases (72.5%) but not in 10 cases (27.5%). There was a significant correlation between the degree of initial caloric weakness and the biphasic conversion of head shaking nystagmus (p = 0.02). In 72.5% of vestibular neuritis cases, head shaking nystagmus was converted to biphasic during the subacute period. The larger the initial canal paresis was present, the more frequent the biphasic conversion of head shaking nystagmus occurred. However, Ménière's disease and benign paroxysmal positional vertigo did not have specific patterns of head shaking nystagmus.

Susceptibility to Fear of Heights in Bilateral Vestibulopathy and Other Disorders of Vertigo and Balance

PubMed Central

Brandt, Thomas; Grill, Eva; Strupp, Michael; Huppert, Doreen

2018-01-01

Aims: To determine the susceptibility to visual height intolerance (vHI) in patients with acquired bilateral vestibulopathy (BVP). The question was whether postural instability in BVP, which is partially compensated for by visual substitution of the impaired vestibular control of balance, leads to an increased susceptibility. This is of particular importance since fear of heights is dependent on body posture, and visual control of balance at heights can no longer substitute vestibular input. For comparison susceptibility to vHI was determined in patients with other vestibular or functional disorders. Methods: A total of 150 patients aged 18 or above who had been referred to the German Center for Vertigo and Balance Disorders and diagnosed to have BVP were surveyed with a standardized questionnaire by specifically trained neurological professionals. Further, 481 patients with other vestibular or functional disorders were included. Results: Susceptibility to vHI was reported by 29% (32 % in females, 25% in males) of the patients with BVP. Patients with vHI were slightly younger (67 vs. 71 years). Seventy percent of those with vHI reported avoidance of climbing, hiking, stairs, darkness, cycling or swimming (84% of those without vHI). Mean age for onset of vHI was 40 years. Susceptibility to vHI was higher in patients with other vertigo disorders than in those with BVP: 64% in those with phobic postural vertigo, 61% in vestibular migraine, 56% in vestibular paroxysmia, 54% in benign paroxysmal positional vertigo, 49% in unilateral vestibulopathy and 48% in Menière's disease. Conclusions: The susceptibility to vHI in BVP was not higher than that of the general population (28%).This allows two explanations that need not be alternatives but contribute to each other: (1) Patients with a bilateral peripheral vestibular deficit largely avoid exposure to heights because of their postural instability. (2) The irrational anxiety to fall from heights triggers increased susceptibility to vHI, not the objective postural instability. However, patients with BVP do not exhibit increased comorbid anxiety disorders. This view is supported by the significantly increased susceptibility to vHI in other vestibular syndromes, which are characterized by an increased comorbidity of anxiety disorders.

Stimulus Characteristics for Vestibular Stochastic Resonance to Improve Balance Function

NASA Technical Reports Server (NTRS)

Mulavara, Ajitkumar; Fiedler, Matthew; Kofman, Igor; Peters, Brian; Wood, Scott; Serrado, Jorge; Cohen, Helen; Reschke, Millard; Bloomberg, Jacob

2010-01-01

Stochastic resonance (SR) is a mechanism by which noise can enhance the response of neural systems to relevant sensory signals. Studies have shown that imperceptible stochastic vestibular electrical stimulation, when applied to normal young and elderly subjects, significantly improved their ocular stabilization reflexes in response to whole-body tilt as well as balance performance during postural disturbances. The goal of this study was to optimize the amplitude characteristics of the stochastic vestibular signals for balance performance during standing on an unstable surface. Subjects performed a standard balance task of standing on a block of foam with their eyes closed. Bipolar stochastic electrical stimulation was applied to the vestibular system using constant current stimulation through electrodes placed over the mastoid process behind the ears. Amplitude of the signals varied in the range of 0-700 microamperes. Balance performance was measured using a force plate under the foam block, and inertial motion sensors were placed on the torso and head. Balance performance with stimulation was significantly greater (10%-25%) than with no stimulation. The signal amplitude at which performance was maximized was in the range of 100-300 microamperes. Optimization of the amplitude of the stochastic signals for maximizing balance performance will have a significant impact on development of vestibular SR as a unique system to aid recovery of function in astronauts after long-duration space flight or in patients with balance disorders.

Psychological traumatization and adverse life events in patients with organic and functional vestibular symptoms.

PubMed

Radziej, Katharina; Schmid, Gabriele; Dinkel, Andreas; Zwergal, Andreas; Lahmann, Claas

2015-08-01

. A relationship has frequently been found between a history of traumatization and the existence of somatoform symptoms. The objective of this study was to examine whether this relationship is also observed for functional, i.e. medically not sufficiently explained, vestibular symptoms (FVS). We tested whether patients with FVS and organically explained vestibular symptoms (OVS) differ with regard to frequencies of previous traumatic experiences and posttraumatic stress symptoms. We also explored whether the impact of previous trauma was associated with characteristics of vestibular symptoms and handicap. . Patients with a diagnosis of OVS (N=185) or FVS (N=158) completed questionnaires about potentially traumatizing experiences (e.g., Childhood Trauma Questionnaire, Impact of Events Scale) and vertigo-related symptoms and handicap (Vertigo Symptom Scale, Vertigo Handicap Questionnaire). . We found no differences between the two patient groups with regard to number or impact of traumatic life events. However, regression analyses across groups revealed that, regardless of their diagnosis, prior traumatic experiences and the presence of posttraumatic stress symptoms including avoidance and intrusion predicted to some extent higher overall balance symptoms and autonomic symptoms of vertigo-related anxiety. . Exposure to trauma and symptoms of posttraumatic stress can contribute to symptom severity and handicap experienced by patients with vestibular symptoms irrespective of their original cause, most likely serving as predisposing, modulating or perpetuating factors. Copyright © 2015 Elsevier Inc. All rights reserved.

A systems concept of the vestibular organs

NASA Technical Reports Server (NTRS)

Mayne, R.

1974-01-01

A comprehensive model of vestibular organ function is presented. The model is based on an analogy with the inertial guidance systems used in navigation. Three distinct operations are investigated: angular motion sensing, linear motion sensing, and computation. These operations correspond to the semicircular canals, the otoliths, and central processing respectively. It is especially important for both an inertial guidance system and the vestibular organs to distinguish between attitude with respect to the vertical on the one hand, and linear velocity and displacement on the other. The model is applied to various experimental situations and found to be corroborated by them.

Functional changes in systemic and regional (intracranial) circulation accompanying low accelerations

NASA Technical Reports Server (NTRS)

Usachev, V. V.; Shinkarevskaya, I. P.

1973-01-01

Functional changes in systemic and cerebral hemodynamics were studied with respect to vestibular stresses. The main types of responses, differing qualitatively with respect to the tolerance of test subjects to low accelerations (particularly to Coriolis accelerations), were established. This is of practical importance in the selection of aircraft and space pilots. The data presented sheds light on the physiological mechanisms of adaptation and disturbed compensation during vestibular stimulation. Further studies in this important field of aerospace medicine are outlined.

Vestibular-related neuroscience and manned space flight

NASA Technical Reports Server (NTRS)

Igarashi, Makoto

1988-01-01

The effects of weightlessness on the human vestibular system are examined, reviewing the results of recent investigations. The functional, neurophysiological, and neurochemical changes which occur during adaptation to weightlessness are discussed; theoretical models proposed to explain the underlying mechanism are outlined; and particular attention is given to the author's experiments on squirrel monkeys. There, good correlations were found between (1) the recovery of locomotor balance function in the acute compensation phase after unilateral labyrinthectomy and (2) the bilateral imbalance in the optical density of GABA-like immunoreactivity.

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

NASA Technical Reports Server (NTRS)

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

2001-01-01

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.

Visual and proprioceptive interaction in patients with bilateral vestibular loss☆

PubMed Central

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

2014-01-01

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

Visual and proprioceptive interaction in patients with bilateral vestibular loss.

PubMed

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

2014-01-01

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.

Effects of high intensity noise on the vestibular system in rats

PubMed Central

Stewart, Courtney; Yu, Yue; Huang, Jun; Maklad, Adel; Tang, Xuehui; Allison, Jerome; Mustain, William; Zhou, Wu; Zhu, Hong

2016-01-01

Some individuals with noise-induced hearing loss (NIHL) also report balance problems. These accompanying vestibular complaints are not well understood. The present study used a rat model to examine the effects of noise exposure on the vestibular system. Rats were exposed to continuous broadband white noise (0–24kHz) at an intensity of 116dB sound pressure level (SPL) via insert ear phones in one ear for three hours under isoflurane anesthesia. Seven days after the exposure, a significant increase in ABR threshold (43.3±1.9dB) was observed in the noise-exposed ears, indicating hearing loss. Effects of noise exposure on vestibular function were assessed by three approaches. First, fluorescein-conjugated phalloidin staining was used to assess vestibular stereocilia following noise exposure. This analysis revealed substantial sensory stereocilia bundle loss in the saccular and utricular maculae as well as in the anterior and horizontal semicircular canal cristae, but not in the posterior semicircular canal cristae. Second, single unit recording of vestibular afferent activity was performed under pentobarbital anesthesia. A total of 548 afferents were recorded from 10 noise-treated rats and 12 control rats. Noise exposure produced a moderate reduction in baseline firing rates of regular otolith afferents and anterior semicircular canal afferents. Also a moderate change was noted in the gain and phase of the horizontal and anterior semicircular canal afferent’s response to sinusoidal head rotation (1 and 2Hz, 45 degrees/s peak velocity). Third, noise exposure did not result in significant changes in gain or phase of the horizontal rotational and translational vestibular-ocular reflex (VOR). These results suggest that noise exposure not only causes hearing loss, but also causes substantial damage in the peripheral vestibular system in the absence of immediate clinically measurable vestibular signs. These peripheral deficits, however, may lead to vestibular disorders over time. PMID:26970474

Vestibular Stimulation and Development of the Small Premature Infant.

ERIC Educational Resources Information Center

Neal, Mary V.

This study was designed to explore the effects of vestibular stimulation on the developmental behavior, respiratory functioning, weight and length gains, and morbidity and mortality rates of premature infants. A total of 20 infants participated in this study in 4 groups of 5 infants each. Group A infants were placed in a motorized hammock within…

Functional Brain Activation in Response to a Clinical Vestibular Test Correlates with Balance

PubMed Central

Noohi, Fatemeh; Kinnaird, Catherine; DeDios, Yiri; Kofman, Igor S.; Wood, Scott; Bloomberg, Jacob; Mulavara, Ajitkumar; Seidler, Rachael

2017-01-01

The current study characterizes brain fMRI activation in response to two modes of vestibular stimulation: Skull tap and auditory tone burst. The auditory tone burst has been used in previous studies to elicit either a vestibulo-spinal reflex [saccular-mediated colic Vestibular Evoked Myogenic Potentials (cVEMP)], or an ocular muscle response [utricle-mediated ocular VEMP (oVEMP)]. Research suggests that the skull tap elicits both saccular and utricle-mediated VEMPs, while being faster and less irritating for subjects than the high decibel tones required to elicit VEMPs. However, it is not clear whether the skull tap and auditory tone burst elicit the same pattern of brain activity. Previous imaging studies have documented activity in the anterior and posterior insula, superior temporal gyrus, inferior parietal lobule, inferior frontal gyrus, and the anterior cingulate cortex in response to different modes of vestibular stimulation. Here we hypothesized that pneumatically powered skull taps would elicit a similar pattern of brain activity as shown in previous studies. Our results provide the first evidence of using pneumatically powered skull taps to elicit vestibular activity inside the MRI scanner. A conjunction analysis revealed that skull taps elicit overlapping activation with auditory tone bursts in the canonical vestibular cortical regions. Further, our postural control assessments revealed that greater amplitude of brain activation in response to vestibular stimulation was associated with better balance control for both techniques. Additionally, we found that skull taps elicit more robust vestibular activity compared to auditory tone bursts, with less reported aversive effects, highlighting the utility of this approach for future clinical and basic science research. PMID:28344549

Neurotology symptoms at referral to vestibular evaluation

PubMed Central

2013-01-01

Background Dizziness-vertigo is common in adults, but clinical providers may rarely diagnose vestibular impairment and referral could be delayed. To assess neurotology symptoms (including triggers) reported by patients with peripheral vestibular disease, during the year just before their referral to vestibular evaluation. Methods 282 patients with peripheral vestibular disease and 282 control subjects accepted to participate. They had no middle ear, retinal, neurological, psychiatric, autoimmune or autonomic disorders. They reported their symptoms by a standardized questionnaire along with their anxiety/depression symptoms. Results Patients were referred after months or years from the onset of their symptoms, 24% of them reported frequent falls with a long clinical evolution; 10% of them reported no vertigo but instability related to specific triggers; 86% patients and 12% control subjects reported instability when moving the head rapidly and 79% patients and 6% control subjects reported instability when changing posture. Seven out of the 9 symptoms explored by the questionnaire allowed the correct classification of circa 95% of the participants (Discriminant function analysis, p < 0.001). High blood pressure, dyslipidemia and anxiety/depression symptoms showed a mild correlation with the total score of symptoms (multiple R2 =0.18, p < 0.001). Conclusions Late referral to vestibular evaluation may underlie a history of frequent falls; some patients may not report vertigo, but instability related to specific triggers, which could be useful to prompt vestibular evaluation. High blood pressure, dyslipidemia and anxiety/depression symptoms may have a mild influence on the report of symptoms of vestibular disease in both, patients and control subjects. PMID:24279682

Macaque Parieto-Insular Vestibular Cortex: Responses to self-motion and optic flow

PubMed Central

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

2011-01-01

The parieto-insular vestibular cortex (PIVC) is thought to contain an important representation of vestibular information. Here we describe responses of macaque PIVC neurons to three-dimensional (3D) vestibular and optic flow stimulation. We found robust vestibular responses to both translational and rotational stimuli in the retroinsular (Ri) and adjacent secondary somatosensory (S2) cortices. PIVC neurons did not respond to optic flow stimulation, and vestibular responses were similar in darkness and during visual fixation. Cells in the upper bank and tip of the lateral sulcus (Ri and S2) responded to sinusoidal vestibular stimuli with modulation at the first harmonic frequency, and were directionally tuned. Cells in the lower bank of the lateral sulcus (mostly Ri) often modulated at the second harmonic frequency, and showed either bimodal spatial tuning or no tuning at all. All directions of 3D motion were represented in PIVC, with direction preferences distributed roughly uniformly for translation, but showing a preference for roll rotation. Spatio-temporal profiles of responses to translation revealed that half of PIVC cells followed the linear velocity profile of the stimulus, one-quarter carried signals related to linear acceleration (in the form of two peaks of direction selectivity separated in time), and a few neurons followed the derivative of linear acceleration (jerk). In contrast, mainly velocity-coding cells were found in response to rotation. Thus, PIVC comprises a large functional region in macaque areas Ri and S2, with robust responses to 3D rotation and translation, but is unlikely to play a significant role in visual/vestibular integration for self-motion perception. PMID:20181599

Distribution of zebrin-immunoreactive Purkinje cell terminals in the cerebellar and vestibular nuclei of birds.

PubMed

Wylie, Douglas R; Pakan, Janelle M P; Huynh, Hang; Graham, David J; Iwaniuk, Andrew N

2012-05-01

Zebrin II (aldolase C) is expressed in a subset of Purkinje cells in the mammalian and avian cerebella such that there is a characteristic parasagittal organization of zebrin-immunopositive stripes alternating with zebrin-immunonegative stripes. Zebrin is expressed not only in the soma and dendrites of Purkinje cells but also in their axonal terminals. Here we describe the distribution of zebrin immunoreactivity in both the vestibular and the cerebellar nuclei of pigeons (Columba livia) and hummingbirds (Calypte anna, Selasphorus rufus). In the medial cerebellar nucleus, zebrin-positive labeling was particularly heavy in the “shell,” whereas the “core” was zebrin negative. In the lateral cerebellar nucleus, labeling was not as heavy, but a positive shell and negative core were also observed. In the vestibular nuclear complex, zebrin-positive terminal labeling was heavy in the dorsolateral vestibular nucleus and the lateral margin of the superior vestibular nucleus. The central and medial regions of the superior nucleus were generally zebrin negative. Labeling was moderate to heavy in the medial vestibular nucleus, particulary the rostral half of the parvocellular subnucleus. A moderate amount of zebrin-positive labeling was present in the descending vestibular nucleus: this was heaviest laterally, and the central region was generally zebrin negative. Zebrin-positive terminals were also observed in the the cerebellovestibular process, prepositus hypoglossi, and lateral tangential nucleus. We discuss our findings in light of similar studies in rats and with respect to the corticonuclear projections to the cerebellar nuclei and the functional connections of the vestibulocerebellum with the vestibular nuclei. Copyright © 2011 Wiley Periodicals, Inc.

Rotatory and collic vestibular evoked myogenic potential testing in normal-hearing and hearing-impaired children.

PubMed

Maes, Leen; De Kegel, Alexandra; Van Waelvelde, Hilde; Dhooge, Ingeborg

2014-01-01

Vertigo and imbalance are often underestimated in the pediatric population, due to limited communication abilities, atypical symptoms, and relatively quick adaptation and compensation in children. Moreover, examination and interpretation of vestibular tests are very challenging, because of difficulties with cooperation and maintenance of alertness, and because of the sometimes nauseatic reactions. Therefore, it is of great importance for each vestibular laboratory to implement a child-friendly test protocol with age-appropriate normative data. Because of the often masked appearance of vestibular problems in young children, the vestibular organ should be routinely examined in high-risk pediatric groups, such as children with a hearing impairment. Purposes of the present study were (1) to determine age-appropriate normative data for two child-friendly vestibular laboratory techniques (rotatory and collic vestibular evoked myogenic potential [cVEMP] test) in a group of children without auditory or vestibular complaints, and (2) to examine vestibular function in a group of children presenting with bilateral hearing impairment. Forty-eight typically developing children (mean age 8 years 0 months; range: 4 years 1 month to 12 years 11 months) without any auditory or vestibular complaints as well as 39 children (mean age 7 years 8 months; range: 3 years 8 months to 12 years 10 months) with a bilateral sensorineural hearing loss were included in this study. All children underwent three sinusoidal rotations (0.01, 0.05, and 0.1 Hz at 50 degrees/s) and bilateral cVEMP testing. No significant age differences were found for the rotatory test, whereas a significant increase of N1 latency and a significant threshold decrease was noticeable for the cVEMP, resulting in age-appropriate normative data. Hearing-impaired children demonstrated significantly lower gain values at the 0.01 Hz rotation and a larger percentage of absent cVEMP responses compared with normal-hearing children. Seventy-four percent of hearing-impaired children showed some type of vestibular abnormality when examined with a combination of rotatory and cVEMP testing, in contrast to an abnormality rate of 60% with cVEMP and a rate of 49% with rotatory testing alone. The observed pediatric age correlations underscore the necessity of age-appropriate normative data to guarantee accurate interpretation of test results. The high percentages of abnormal vestibular test results in hearing-impaired children emphasize the importance of vestibular assessment in these children because the integrity of the vestibular system is a critical factor for motor and psychological development.

Analysis of nystagmus response to a pseudorandom velocity input

NASA Technical Reports Server (NTRS)

Lessard, C. S.

1986-01-01

Space motion sickness was not reported during the first Apollo missions; however, since Apollo 8 through the current Shuttle and Skylab missions, approximately 50% of the crewmembers have experienced instances of space motion sickness. Space motion sickness, renamed space adaptation syndrome, occurs primarily during the initial period of a mission until habilation takes place. One of NASA's efforts to resolve the space adaptation syndrome is to model the individual's vestibular response for basis knowledge and as a possible predictor of an individual's susceptibility to the disorder. This report describes a method to analyse the vestibular system when subjected to a pseudorandom angular velocity input. A sum of sinusoids (pseudorandom) input lends itself to analysis by linear frequency methods. Resultant horizontal ocular movements were digitized, filtered and transformed into the frequency domain. Programs were developed and evaluated to obtain the (1) auto spectra of input stimulus and resultant ocular resonse, (2) cross spectra, (3) the estimated vestibular-ocular system transfer function gain and phase, and (4) coherence function between stimulus and response functions.

Localization of soluble guanylate cyclase activity in the guinea pig inner ear.

PubMed

Takumida, M; Anniko, M; Popa, R; Zhang, D M

2000-01-01

The aim of this study was to characterize the nitric oxide (NO) receptor soluble guanylate cyclase (sGC), to determine the cells targeted by NO and to elucidate the function of the NO/cGMP pathway in the inner ear. sGC activity in the inner ear was localized by immunohistochemical detection of NO-stimulated cGMP. Soluble guanylate cyclase activity in the cochlea was detected in the nerve endings underneath the outer and inner hair cells, supporting cells, stria vascularis and vessels. In the vestibular organs, sGC activity was detected in the cytoplasm of sensory cells, nerve fibres, dark cells and transitional cells and vessels. These findings suggest that the NO/cGMP pathway may be involved in regulatory processes in neurotransmission, blood flow and inner ear fluid homeostasis.

Diagnostics and therapy of vestibular schwannomas – an interdisciplinary challenge

PubMed Central

Rosahl, Steffen; Bohr, Christopher; Lell, Michael; Hamm, Klaus; Iro, Heinrich

2017-01-01

Vestibular schwannomas (VS) expand slowly in the internal auditory canal, in the cerebellopontine angle, inside the cochlear and the labyrinth. Larger tumors can displace and compress the brainstem. With an annual incidence of 1:100,000 vestibular schwannoma represent 6–7% of all intracranial tumors. In the cerebellopontine angle they are by far the most neoplasm with 90% of all lesions located in this region. Magnetic resonance imaging (MRI), audiometry, and vestibular diagnostics are the mainstays of the clinical workup for patients harboring tumors. The first part of this paper delivers an overview of tumor stages, the most common grading scales for facial nerve function and hearing as well as a short introduction to the examination of vestibular function. Upholding or improving quality of life is the central concern in counseling and treating a patient with vestibular schwannoma. Preservation of neuronal function is essential and the management options – watchful waiting, microsurgery and stereotactic radiation – should be custom-tailored to the individual situation of the patient. Continuing interdisciplinary exchange is important to monitor treatment quality and to improve treatment results. Recently, several articles and reviews have been published on the topic of vestibular schwannoma. On the occasion of the 88th annual meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck surgery a special volume of the journal “HNO” will be printed. Hence this presentation has been designed to deviate from the traditional standard which commonly consists of a pure literature review. The current paper was conceptually woven around a series of interdisciplinary cases that outline examples for every stage of the disease that show characteristic results for management options to date. Systematic clinical decision pathways have been deduced from our experience and from results reported in the literature. These pathways are graphically outlined after the case presentations. Important criteria for decision making are size and growth rate of the tumor, hearing of the patient and the probability of total tumor resection with preservation of hearing and facial nerve function, age and comorbidity of the patient, best possible control of vertigo and tinnitus and last but not least the patient’s preference and choice. In addition to this, the experience and the results of a given center with each treatment modality will figure in the decision making process. We will discuss findings that are reported in the literature regarding facial nerve function, hearing, vertigo, tinnitus, and headache and reflect on recent studies on their influence on the patient’s quality of life. Vertigo plays an essential role in this framework since it is an independent predictor of quality of life and a patient’s dependence on social welfare. Pathognomonic bilateral vestibular schwannomas that occur in patients suffering from neurofibromatosis typ-2 (NF2) differ from spontaneous unilateral tumors in their biologic behavior. Treatment of neurofibromatosis type-2 patients requires a multidisciplinary team, especially because of the multitude of separate intracranial and spinal lesions. Off-label chemotherapy with Bevacizumab can stabilize tumor size of vestibular schwannomas and even improve hearing over longer periods of time. Hearing rehabilitation in NF2 patients can be achieved with cochlear and auditory brainstem implants. PMID:29279723

Changes in Listing plane thickness caused by vestibular schwannoma: a parameter for evaluating the accuracy of the gravity-oriented internal model.

PubMed

Tsutsumi, Takeshi; Ikeda, Takuo; Watanabe, Kensuke; Kikuchi, Shigeru

2011-12-01

Three-dimensional analysis of video-oculograms can be used to calculate Listing plane for patients and experimental subjects. Listing plane reflects the head's orientation with respect to gravity, which suggests that the plane is derived from otolithic vestibular input, itself, or from a gravity-oriented internal model constructed through integration of visual, vestibular, and proprioceptive sensory inputs. The goal of this study was to determine whether the Listing plane can serve as a parameter for evaluating static (peripheral or central) vestibular function. Prospective study. Tertiary referral center. Healthy subjects and patients with unilateral vestibular schwannoma without any previous treatment. Diagnostic. Video-oculograms were recorded from healthy subjects (aged 36.8 ± 6.3 yr) and from patients (aged 60.3 ± 7.5 yr) during voluntary gaze with the head in an upright or each-side-down orientation, and the thicknesses of the calculated Listing planes were then compared. Results revealed thickening of the Listing plane in patients only when the head was in an impaired-side-down orientation (1.250 ± 0.795 and 1.074 ± 0.759 degrees in the right- and left-side-down head orientations in healthy subjects versus 2.222 ± 1.237 degrees in the impaired-side-down orientation in patients), and this thickening correlated with caloric weakness. By contrast, neither the sensation of postural instability nor postural disturbance in force platform recordings contributed to the thickness of Listing plane. The thickness of the Listing plane could be a novel parameter for quantitatively evaluating static vestibular (otolithic) function, although central compensation might exist.

Head-shaking nystagmus predicts greater disability in unilateral peripheral vestibulopathy.

PubMed

Angeli, Simon I; Velandia, Sandra; Snapp, Hillary

2011-01-01

The objective of this study was to determine the association of the bedside test of head-shaking nystagmus (HSN) with patients' self-perceived dizziness handicap as well as this test's sensitivity and specificity in unilateral peripheral vestibular hypofunction. A retrospective case-control study was performed. The study was held at an academic, tertiary referral center. Fifty-three adult patients with unilateral peripheral hypofunction defined by the caloric test of the videonystagmography with documented bedside HSN and who had completed questionnaires of self-perceived dizziness handicap were included. The sensitivity and specificity of the bedside HSN in patients and 10 healthy controls in diagnosing unilateral vestibular hypofunction defined by videonystagmographic caloric testing and by abnormal gain and symmetry of the vestibular-ocular reflex by rotary chair testing were determined. Scores of the screening test of the Dizziness Handicap Index and Functional Level Scale questionnaires were taken. When using the caloric irrigation test as the reference standard for unilateral vestibular hypofunction, the sensitivity, specificity, and positive predictive value of the bedside HSN were 31%, 96%, and 97%, respectively. When comparing with results of rotational chair testing (vestibular-ocular reflex gain and symmetry), the sensitivity of the HSN test increases to 71%. Patients with positive bedside HSN had higher scores (greater self-perceived dizziness handicap) of the Dizziness Handicap Index (P = .049) and higher (worse) scores of the Functional Level Scale (P = .0377) than those with negative bedside HSN (Wilcoxon rank test). Greater perceived handicap was correlated with a positive bedside HSN in patients with unilateral peripheral vestibulopathy. The HSN has sufficient sensitivity to be used as screening test of uncompensated vestibulopathy in this series. However, a negative HSN alone does not rule out the diagnosis of peripheral vestibular dysfunction. Copyright © 2011 Elsevier Inc. All rights reserved.

Lateral Semicircular Canal Asymmetry in Idiopathic Scoliosis: An Early Link between Biomechanical, Hormonal and Neurosensory Theories?

PubMed Central

Hitier, Martin; Hamon, Michèle; Denise, Pierre; Lacoudre, Julien; Thenint, Marie-Aude; Mallet, Jean-François; Moreau, Sylvain; Quarck, Gaëlle

2015-01-01

Introduction Despite its high incidence and severe morbidity, the physiopathogenesis of adolescent idiopathic scoliosis (AIS) is still unknown. Here, we looked for early anomalies in AIS which are likely to be the cause of spinal deformity and could also be targeted by early treatments. We focused on the vestibular system, which is suspected of acting in AIS pathogenesis and which exhibits an end organ with size and shape fixed before birth. We hypothesize that, in adolescents with idiopathic scoliosis, vestibular morphological anomalies were already present at birth and could possibly have caused other abnormalities. Materials and Methods The vestibular organ of 18 adolescents with AIS and 9 controls were evaluated with MRI in a prospective case controlled study. We studied lateral semicircular canal orientation and the three semicircular canal positions relative to the midline. Lateral semicircular canal function was also evaluated by vestibulonystagmography after bithermal caloric stimulation. Results The left lateral semicircular canal was more vertical and further from the midline in AIS (p = 0.01) and these two parameters were highly correlated (r = -0.6; p = 0.02). These morphological anomalies were associated with functional anomalies in AIS (lower excitability, higher canal paresis), but were not significantly different from controls (p>0.05). Conclusion Adolescents with idiopathic scoliosis exhibit morphological vestibular asymmetry, probably determined well before birth. Since the vestibular system influences the vestibulospinal pathway, the hypothalamus, and the cerebellum, this indicates that the vestibular system is a possible cause of later morphological, hormonal and neurosensory anomalies observed in AIS. Moreover, the simple lateral SCC MRI measurement demonstrated here could be used for early detection of AIS, selection of children for close follow-up, and initiation of preventive treatment before spinal deformity occurs. PMID:26186348

Current diagnostic procedures for diagnosing vertigo and dizziness

PubMed Central

Walther, Leif Erik

2017-01-01

Vertigo is a multisensory syndrome that otolaryngologists are confronted with every day. With regard to the complex functions of the sense of orientation, vertigo is considered today as a disorder of the sense of direction, a disturbed spatial perception of the body. Beside the frequent classical syndromes for which vertigo is the leading symptom (e.g. positional vertigo, vestibular neuritis, Menière’s disease), vertigo may occur as main or accompanying symptom of a multitude of ENT-related diseases involving the inner ear. It also concerns for example acute and chronic viral or bacterial infections of the ear with serous or bacterial labyrinthitis, disorders due to injury (e.g. barotrauma, fracture of the oto-base, contusion of the labyrinth), chronic-inflammatory bone processes as well as inner ear affections in the perioperative course. In the last years, diagnostics of vertigo have experienced a paradigm shift due to new diagnostic possibilities. In the diagnostics of emergency cases, peripheral and central disorders of vertigo (acute vestibular syndrome) may be differentiated with simple algorithms. The introduction of modern vestibular test procedures (video head impulse test, vestibular evoked myogenic potentials) in the clinical practice led to new diagnostic options that for the first time allow a complex objective assessment of all components of the vestibular organ with relatively low effort. Combined with established methods, a frequency-specific assessment of the function of vestibular reflexes is possible. New classifications allow a clinically better differentiation of vertigo syndromes. Modern radiological procedures such as for example intratympanic gadolinium application for Menière’s disease with visualization of an endolymphatic hydrops also influence current medical standards. Recent methodical developments significantly contributed to the possibilities that nowadays vertigo can be better and more quickly clarified in particular in otolaryngology. PMID:29279722

Beyond Dizziness: Virtual Navigation, Spatial Anxiety and Hippocampal Volume in Bilateral Vestibulopathy

PubMed Central

Kremmyda, Olympia; Hüfner, Katharina; Flanagin, Virginia L.; Hamilton, Derek A.; Linn, Jennifer; Strupp, Michael; Jahn, Klaus; Brandt, Thomas

2016-01-01

Bilateral vestibulopathy (BVP) is defined as the impairment or loss of function of either the labyrinths or the eighth nerves. Patients with total BVP due to bilateral vestibular nerve section exhibit difficulties in spatial memory and navigation and show a loss of hippocampal volume. In clinical practice, most patients do not have a complete loss of function but rather an asymmetrical residual functioning of the vestibular system. The purpose of the current study was to investigate navigational ability and hippocampal atrophy in BVP patients with residual vestibular function. Fifteen patients with BVP and a group of age- and gender- matched healthy controls were examined. Self-reported questionnaires on spatial anxiety and wayfinding were used to assess the applied strategy of wayfinding and quality of life. Spatial memory and navigation were tested directly using a virtual Morris Water Maze Task. The hippocampal volume of these two groups was evaluated by voxel-based morphometry. In the patients, the questionnaire showed a higher spatial anxiety and the Morris Water Maze Task a delayed spatial learning performance. MRI revealed a significant decrease in the gray matter mid-hippocampal volume (Left: p = 0.006, Z = 4.58, Right: p < 0.001, Z = 3.63) and posterior parahippocampal volume (Right: p = 0.005, Z = 4.65, Left: p < 0.001, Z = 3.87) compared to those of healthy controls. In addition, a decrease in hippocampal formation volume correlated with a more dominant route-finding strategy. Our current findings demonstrate that even partial bilateral vestibular loss leads to anatomical and functional changes in the hippocampal formation and objective and subjective behavioral deficits. PMID:27065838

The repetition timing of high frequency afferent stimulation drives the bidirectional plasticity at central synapses in the rat medial vestibular nuclei.

PubMed

Scarduzio, M; Panichi, R; Pettorossi, V E; Grassi, S

2012-10-25

In this study we show that high frequency stimulation (HFS, 100Hz) of afferent fibers to the medial vestibular nucleus (MVN) can induce opposite long-term modifications of synaptic responses in the type B neurons depending upon the stimulation pattern. Long burst stimulation (LBS: 2s) and short burst stimulation (SBS: 0.55s) were applied with different burst number (BN) and inter-burst intervals (IBI). It results that both LBS and SBS can induce either N-methyl-d aspartate receptors (NMDARs)-mediated long-term potentiation (LTP) or long-term depression (LTD), depending on temporal organization of repetitive bursts. In particular, the IBI plays a relevant role in guiding the shift from LTP to LTD since by using both LBS and SBS LTP is induced by shorter IBI than LTD. By contrast, the sign of long-term effect does not depend on the mean impulse frequency evaluated within the entire stimulation period. Therefore, the patterns of repetitive vestibular activation with different ratios between periods of increased activity and periods of basal activity may lead to LTP or LTD probably causing different levels of postsynaptic Ca(2+). On the whole, this study demonstrates that glutamatergic vestibular synapse in the MVN can undergo NMDAR-dependent bidirectional plasticity and puts forward a new aspect for understanding the adaptive and compensatory plasticity of the oculomotor responses. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Neuroticism modulates brain visuo-vestibular and anxiety systems during a virtual rollercoaster task.

PubMed

Riccelli, Roberta; Indovina, Iole; Staab, Jeffrey P; Nigro, Salvatore; Augimeri, Antonio; Lacquaniti, Francesco; Passamonti, Luca

2017-02-01

Different lines of research suggest that anxiety-related personality traits may influence the visual and vestibular control of balance, although the brain mechanisms underlying this effect remain unclear. To our knowledge, this is the first functional magnetic resonance imaging (fMRI) study that investigates how individual differences in neuroticism and introversion, two key personality traits linked to anxiety, modulate brain regional responses and functional connectivity patterns during a fMRI task simulating self-motion. Twenty-four healthy individuals with variable levels of neuroticism and introversion underwent fMRI while performing a virtual reality rollercoaster task that included two main types of trials: (1) trials simulating downward or upward self-motion (vertical motion), and (2) trials simulating self-motion in horizontal planes (horizontal motion). Regional brain activity and functional connectivity patterns when comparing vertical versus horizontal motion trials were correlated with personality traits of the Five Factor Model (i.e., neuroticism, extraversion-introversion, openness, agreeableness, and conscientiousness). When comparing vertical to horizontal motion trials, we found a positive correlation between neuroticism scores and regional activity in the left parieto-insular vestibular cortex (PIVC). For the same contrast, increased functional connectivity between the left PIVC and right amygdala was also detected as a function of higher neuroticism scores. Together, these findings provide new evidence that individual differences in personality traits linked to anxiety are significantly associated with changes in the activity and functional connectivity patterns within visuo-vestibular and anxiety-related systems during simulated vertical self-motion. Hum Brain Mapp 38:715-726, 2017. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Vestibular-evoked myogenic potentials, clinical evaluation, and imaging findings in multiple sclerosis.

PubMed

Güven, Hayat; Bayır, Omer; Aytaç, Emrah; Ozdek, Ali; Comoğlu, Selim Selçuk; Korkmaz, Hakan

2014-02-01

Vestibular-evoked myogenic potentials (VEMP), short-latency electromyographic responses elicited by acoustic stimuli, evaluate the function of vestibulocollic reflex and may give information about brainstem function. The aim of the present study is to evaluate the potential contribution of VEMP to the diagnosis of multiple sclerosis (MS). Fifty patients with MS and 30 healthy control subjects were included in this study. The frequency of VEMP p1-n1 and n2-p2 waves; mean p1, n1, n2, and p2 latency; and mean p1-n1 and n2-p2 amplitude were determined. The relation between clinical and imaging findings and VEMP parameters was evaluated. The p1-n1 and n2-p2 waves were more frequently absent in MS than in control subjects [p1-n1 wave absent: MS, 25 (25 %) ears; control, 6 (10 %) ears; P ≤ 0.02] [n2-p2 wave absent: MS, 44 (44 %) ears; control, 7 (12 %) ears; P ≤ 0.001]. The mean p1-n1 amplitude was lower in MS than in control subjects (MS, 19.1 ± 7.2 μV; control, 23.3 ± 7.4 μV; P ≤ 0.002). A total of 24/50 (48 %) MS patients had VEMP abnormalities (absent responses and/or prolonged latencies). VEMP abnormalities were more frequent in patients with than without vestibular symptoms (P ≤ 0.02) and with brainstem functional system score (FSS) ≥ 1 than FSS = 0 (P ≤ 0.02). In patients with MS, absence of p1-n1 wave was more frequent in patients with than without vestibular symptoms [absence of p1-n1 wave: vestibular symptoms, 9 (45 %) ears; no vestibular symptoms, 16 (20 %) ears; P ≤ 0.03] and patients with Expanded Disability Status Scale (EDSS) score ≥ 5.5 [absence of p1-n1 wave: EDSS ≥ 5.5, 7 (70 %) ears; EDSS <5.5, 18 (20 %) ears; P ≤ 0.001]. Abnormal VEMP may be noted in MS patients, especially those with vestibular symptoms and greater disability. The VEMP test may complement other studies for diagnosis and follow-up of patients with MS.

Vestibular-Evoked Myogenic Potentials in Bilateral Vestibulopathy

PubMed Central

Rosengren, Sally M.; Welgampola, Miriam S.; Taylor, Rachael L.

2018-01-01

Bilateral vestibulopathy (BVP) is a chronic condition in which patients have a reduction or absence of vestibular function in both ears. BVP is characterized by bilateral reduction of horizontal canal responses; however, there is increasing evidence that otolith function can also be affected. Cervical and ocular vestibular-evoked myogenic potentials (cVEMPs/oVEMPs) are relatively new tests of otolith function that can be used to test the saccule and utricle of both ears independently. Studies to date show that cVEMPs and oVEMPs are often small or absent in BVP but are in the normal range in a significant proportion of patients. The variability in otolith function is partly due to the heterogeneous nature of BVP but is also due to false negative and positive responses that occur because of the large range of normal VEMP amplitudes. Due to their variability, VEMPs are not part of the diagnosis of BVP; however, they are helpful complementary tests that can provide information about the extent of disease within the labyrinth. This article is a review of the use of VEMPs in BVP, summarizing the available data on VEMP abnormalities in patients and discussing the limitations of VEMPs in diagnosing bilateral loss of otolith function. PMID:29719527

Treatment of peripheral vestibular dysfunction using photobiomodulation

NASA Astrophysics Data System (ADS)

Lee, Min Young; Hyun, Jai-Hwan; Suh, Myung-Whan; Ahn, Jin-Chul; Chung, Phil-Sang; Jung, Jae Yun; Rhee, Chung Ku

2017-08-01

Gentamicin, which is still used in modern medicine, is a known vestibular toxic agent, and various degrees of balance problems have been observed after exposure to this pharmacologic agent. Photobiomodulation is a candidate therapy for vertigo due to its ability to reach deep inner ear organs such as the cochlea. Previous reports have suggested that photobiomodulation can improve hearing and cochlea function. However, few studies have examined the effect of photobiomodulation on balance dysfunction. We used a rat model to mimic human vestibulopathy resulting from gentamicin treatment and evaluated the effect of photobiomodulation on vestibular toxicity. Slow harmonic acceleration (SHA) rotating platform testing was used for functional evaluation and both qualitative and quantitative epifluorescence analyses of cupula histopathology were performed. Animals were divided into gentamicin only and gentamicin plus laser treatment groups. Laser treatment was applied to one ear, and function and histopathology were evaluated in both ears. Decreased function was observed in both ears after gentamicin treatment, demonstrated by low gain and no SHA asymmetry. Laser treatment minimized the damage resulting from gentamicin treatment as shown by SHA asymmetry and recovered gain in the treated ear. Histology results reflected the functional results, showing increased hair cell density and epifluorescence intensity in laser-treated cupulae.

Clinical classification and neuro-vestibular evaluation in chronic dizziness.

PubMed

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

2015-01-01

This study attempts to clarify the clinical characteristics of chronic dizziness and its relationships with specific vestibular, oculomotor, autonomic and psychiatric dysfunctions. 73 Patients with idiopathic chronic dizziness were recruited and classified based on history taking and clinical examination into the following four clinical subgroups; vestibular migraine (VM), dysautonomia, psychogenic, and unspecified groups. They were also evaluated using oculomotor, otolithic and autonomic function tests, and psychologic investigation. Patients in the VM group showed a high proportion of abnormality on smooth pursuit and otolithic function testing compared to the other groups. The dysautonomia group revealed significant abnormalities in sympathetic and cardiovagal autonomic function, while the psychogenic group had a high frequency of abnormality in sympathetic autonomic testing and in Beck's anxiety inventory scale. The unspecified group showed abnormalities on saccade, smooth pursuit and autonomic function testing. Clinical classification of patients with chronic dizziness was relevant and they showed a correlation with disease-specific abnormal results in oculomotor, otolithic, autonomic function and psychology testing. Appropriate diagnostic investigation based on precise clinical diagnosis of chronic dizziness reduces the need for extensive laboratory testing, neuroimaging, and other low-yield tests. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Interaction of vestibular, echolocation, and visual modalities guiding flight by the big brown bat, Eptesicus fuscus.

PubMed

Horowitz, Seth S; Cheney, Cheryl A; Simmons, James A

2004-01-01

The big brown bat (Eptesicus fuscus) is an aerial-feeding insectivorous species that relies on echolocation to avoid obstacles and to detect flying insects. Spatial perception in the dark using echolocation challenges the vestibular system to function without substantial visual input for orientation. IR thermal video recordings show the complexity of bat flights in the field and suggest a highly dynamic role for the vestibular system in orientation and flight control. To examine this role, we carried out laboratory studies of flight behavior under illuminated and dark conditions in both static and rotating obstacle tests while administering heavy water (D2O) to impair vestibular inputs. Eptesicus carried out complex maneuvers through both fixed arrays of wires and a rotating obstacle array using both vision and echolocation, or when guided by echolocation alone. When treated with D2O in combination with lack of visual cues, bats showed considerable decrements in performance. These data indicate that big brown bats use both vision and echolocation to provide spatial registration for head position information generated by the vestibular system.

Vestibular rehabilitation using video gaming in adults with dizziness: a pilot study.

PubMed

Phillips, J S; Fitzgerald, J; Phillis, D; Underwood, A; Nunney, I; Bath, A

2018-03-01

To determine the effectiveness of vestibular rehabilitation using the Wii Fit balance platform, in adults with dizziness. A single-site prospective clinical trial was conducted in a university hospital in the UK. Forty patients with dizziness, who would normally be candidates for vestibular rehabilitation, were identified and considered as potential participants. Participants were randomised into either the treatment group (the Wii Fit group) or the control group (standard customised vestibular rehabilitation protocol). Participants were assessed over a 16-week period using several balance and quality of life questionnaires. Both exercise regimes resulted in a reduction of dizziness and an improvement in quality of life scores over time, but no statistically significant difference between the two interventions was identified. This pilot study demonstrated that use of the Wii Fit balance platform resulted in a statistically significant improvement in balance function and quality of life. Furthermore, outcomes were comparable to a similar group of individuals following a standard customised vestibular rehabilitation protocol. The study provides useful information to inform the design and execution of a larger clinical trial.

Influence of Caloric Vestibular Stimulation on Body Experience in Healthy Humans

PubMed Central

Schönherr, Andreas; May, Christian Albrecht

2016-01-01

The vestibular system has more connections with and influence on higher cortical centers than previously thought. These interactions with higher cortical centers and the phenomena that they elicit require a structural intact cerebral cortex. To date, little is known about the role and influence of the vestibular system on one’s body experience. In this study we show that caloric vestibular stimulation (CVS) in healthy participants has an effect on the perceptive component of one’s body experience. After CVS all participants showed a statistically significant difference of thigh width estimation. In contrast to previous studies, which demonstrated an influence of CVS on higher cortical centers with an intact cerebral cortex both the cognitive and affective component of body experience were not effected by the CVS. Our results demonstrate the influence of the vestibular system on body perception and emphasize its role in modulating different perceptive-qualities which contributes to our body experience. We found that CVS has a limited influence on one’s conscious state, thought process and higher cortical functions. PMID:27013995

Vertigo and dizziness in children.

PubMed

Jahn, Klaus; Langhagen, Thyra; Heinen, Florian

2015-02-01

Vertigo and dizziness occur with considerable frequency in childhood and adolescence. Most causes are benign and treatable. This review aims to make physicians more alert to the frequent causes of dizziness in the young. Epidemiological data confirm that migraine-related syndromes are the most common cause of vertigo in children. Vestibular migraine and benign paroxysmal vertigo have now been defined by the International Classification of Headache Disorders. About half of the adolescents with vertigo and dizziness show psychiatric comorbidity and somatization. Vestibular paroxysmia has been described as a new entity in children that can be treated with low doses of carbamazepine. To assess vestibular deficits, video head impulses (for the semicircular canals) and vestibular-evoked myogenic potentials (for the otoliths) are increasingly being used. Pediatricians and neuro-otologists should be aware of the full spectrum of causes of vertigo and dizziness in children and adolescents. Vestibular function can reliably be tested nowadays. Although treatment for the common migraine-related syndromes can be done in analogy to the treatment of migraine in general, specific approaches are required for somatoform vertigo, the most frequent diagnosis in adolescent girls.

Virtual head rotation reveals a process of route reconstruction from human vestibular signals

PubMed Central

Day, Brian L; Fitzpatrick, Richard C

2005-01-01

The vestibular organs can feed perceptual processes that build a picture of our route as we move about in the world. However, raw vestibular signals do not define the path taken because, during travel, the head can undergo accelerations unrelated to the route and also be orientated in any direction to vary the signal. This study investigated the computational process by which the brain transforms raw vestibular signals for the purpose of route reconstruction. We electrically stimulated the vestibular nerves of human subjects to evoke a virtual head rotation fixed in skull co-ordinates and measure its perceptual effect. The virtual head rotation caused subjects to perceive an illusory whole-body rotation that was a cyclic function of head-pitch angle. They perceived whole-body yaw rotation in one direction with the head pitched forwards, the opposite direction with the head pitched backwards, and no rotation with the head in an intermediate position. A model based on vector operations and the anatomy and firing properties of semicircular canals precisely predicted these perceptions. In effect, a neural process computes the vector dot product between the craniocentric vestibular vector of head rotation and the gravitational unit vector. This computation yields the signal of body rotation in the horizontal plane that feeds our perception of the route travelled. PMID:16002439

Vestibular rehabilitation outcomes in chronic vertiginous patients through computerized dynamic visual acuity and Gaze stabilization test.

PubMed

Badaracco, Carlo; Labini, Francesca Sylos; Meli, Annalisa; De Angelis, Ezio; Tufarelli, Davide

2007-09-01

To evaluate the efficiency of the rehabilitative protocols in patients with labyrinthine hypofunction, focusing on computerized dynamic visual acuity test (DVAt) and Gaze stabilization test (GST) specifically evaluating the vestibulo-oculomotor reflex (VOR) changes due to vestibular rehabilitation. Consecutive sample study. Day hospital in Ears, Nose, and Throat Rehabilitation Unit. Thirty-two patients with chronic dizziness with a mean age of 60.74 years. Patients performed one cycle of 12 daily rehabilitation sessions (2 h each) consisting of exercises aimed at improving VOR gain. The rehabilitation program included substitutional and/or habitudinal exercises, exercises on a stability platform, and exercises on a moving footpath with rehabilitative software. Dizziness Handicap Inventory and Activities-specific Balance Confidence Scale. Computerized dynamic posturography, computerized DVAt, and GST. The patients significantly improved in all the tests. Vestibular rehabilitation improved the quality of life by reducing the handicap index and improving the ability in everyday tasks. The recovery of the vestibular-ocular reflex and vestibular-spinal reflex efficiency was objectively proven by instrumental testing. The DVAt and the GST allow to objectively quantify the fixation ability at higher frequencies and speeds (main VOR function). Moreover, these new parameters permit to completely evaluate vestibular rehabilitation outcomes, adding new information to the generally used tests that only assess vestibulospinal reflex.

Cellular target of streptomycin in the internal ear.

PubMed

Meza, G; López, I; Paredes, M A; Peñaloza, Y; Poblano, A

1989-01-01

The cellular target of streptomycin (STP) was investigated by analyzing the activity of glutamate decarboxylase (GAD) or choline acetyltransferase (ChAT) enzymes of synthesis of GABA and acetylcholine (Ach), respectively, [supposedly located in hair cells (GAD) or efferent terminals (ChAT)] in control and in 50 day-STP-treated colored guinea pig vestibular homogenates. Vestibular and auditory function were assessed by measuring postrotatory nystagmus response (PNR) and auditory brainstem evoked potentials (ABP). Morphological changes were followed by light and electron microscopy. STP-treated animals exhibited a GAD decrease of 83.6% with respect to controls whereas ChAT did not suffer any change. Assessment of PNR and ABP showed that STP affected only the former since animals lost it between the 20th and the 30th day of treatment, whereas ABP was not modified. Morphological experiments detected vestibular hair cell deterioration as the only cell type affected by STP. These results confirm the predilection of STP to affect vestibular function by damage to hair cells and show that this effect can be followed by measurement of GAD and ChAT in the vestibule as markers for hair cells and efferent terminals, respectively.

Vestibular evoked myogenic potential (VEMP) with galvanic stimulation in normal subjects.

PubMed

Cunha, Luciana Cristina Matos; Labanca, Ludimila; Tavares, Maurício Campelo; Gonçalves, Denise Utsch

2014-01-01

The vestibular evoked myogenic potential (VEMP) generated by galvanic vestibular stimulation (GVS) is related to the vestibulo-spinal pathway. The response recorded from soleus muscle is biphasic with onset of short latency (SL) component around 60 ms and medium latency (ML) component around 100 ms. The first component reflects otolith function (sacule and utricle) and the last deals with semicircular canals. To describe VEMP generated by GVS. In this cross-sectional clinical study, VEMP was generated by 2 mA/400 ms binaural GVS, frequency of 5-6 ms that was recorded from soleus muscles of 13 healthy adults, mean age 56 years. The subjects remained standing, head turned contralateral to the GVS applied to the mastoid. Thirty GVS were applied to the mastoid in the position cathode right anode left, followed by 30 in inverted position. SL and ML were measured. SL and ML components were recorded from both legs of all participants and were similar. The average of SL component was 54 ms and of ML was 112 ms. The components SL and ML of the VEMP response in soleus were reproducible and are useful measures of vestibular-spinal function.

Causes and Consequences of Sensory Hair Cell Damage and Recovery in Fishes.

PubMed

Smith, Michael E; Monroe, J David

2016-01-01

Sensory hair cells are the mechanotransductive receptors that detect gravity, sound, and vibration in all vertebrates. Damage to these sensitive receptors often results in deficits in vestibular function and hearing. There are currently two main reasons for studying the process of hair cell loss in fishes. First, fishes, like other non-mammalian vertebrates, have the ability to regenerate hair cells that have been damaged or lost via exposure to ototoxic chemicals or acoustic overstimulation. Thus, they are used as a biomedical model to understand the process of hair cell death and regeneration and find therapeutics that treat or prevent human hearing loss. Secondly, scientists and governmental natural resource managers are concerned about the potential effects of intense anthropogenic sounds on aquatic organisms, including fishes. Dr. Arthur N. Popper and his students, postdocs and research associates have performed pioneering experiments in both of these lines of fish hearing research. This review will discuss the current knowledge regarding the causes and consequences of both lateral line and inner ear hair cell damage in teleost fishes.

Vestibular Deficits Following Youth Concussion

PubMed Central

Corwin, Daniel J.; Wiebe, Douglas J.; Zonfrillo, Mark R.; Grady, Matthew F.; Robinson, Roni L.; Goodman, Arlene M.; Master, Christina L.

2015-01-01

Objective To characterize the prevalence and recovery of pediatric patients with concussion who manifest clinical vestibular deficits, and to describe the correlation of these deficits with neurocognitive function, based on computerized neurocognitive testing, in a sample of pediatric patients with concussion. Methods This was a retrospective cohort study of patients age 5–18 years old with concussion referred to a tertiary pediatric hospital-affiliated sports medicine clinic from 7/1/2010–12/31/2011. A random sample of all eligible patient visits was obtained, and all related visits for those patients were reviewed. Results 247 patients were chosen from 3740 eligible visits for detailed review and abstraction. 81% showed a vestibular abnormality on initial clinical exam. Those patients with vestibular signs on initial exam took a significantly longer time to return to school (median 59 days vs. 6 days, p=0.001) or to be fully cleared (median 106 days vs. 29 days, p=0.001). They additionally scored more poorly on initial computerized neurocognitive testing, and took longer for neurocognitive deficits to recover. Those patients with three or more prior concussions had a higher prevalence of vestibular deficits and took longer for those deficits to resolve. Conclusion Vestibular deficits in children and adolescents with a history of concussion are highly prevalent. These deficits appear to be associated with extended recovery times and poorer performance on neurocognitive testing. Further studies evaluating the effectiveness of vestibular therapy on improving such deficits are warranted. PMID:25748568

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

NASA Technical Reports Server (NTRS)

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

1999-01-01

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.

Influence of galvanic vestibular stimulation on egocentric and object-based mental transformations.

PubMed

Lenggenhager, Bigna; Lopez, Christophe; Blanke, Olaf

2008-01-01

The vestibular system analyses angular and linear accelerations of the head that are important information for perceiving the location of one's own body in space. Vestibular stimulation and in particular galvanic vestibular stimulation (GVS) that allow a systematic modification of vestibular signals has so far mainly been used to investigate vestibular influence on sensori-motor integration in eye movements and postural control. Comparatively, only a few behavioural and imaging studies have investigated how cognition of space and body may depend on vestibular processing. This study was designed to differentiate the influence of left versus right anodal GVS compared to sham stimulation on object-based versus egocentric mental transformations. While GVS was applied, subjects made left-right judgments about pictures of a plant or a human body presented at different orientations in the roll plane. All subjects reported illusory sensations of body self-motion and/or visual field motion during GVS. Response times in the mental transformation task were increased during right but not left anodal GVS for the more difficult stimuli and the larger angles of rotation. Post-hoc analyses suggested that the interfering effect of right anodal GVS was only present in subjects who reported having imagined turning themselves to solve the mental transformation task (egocentric transformation) as compared to those subjects having imagined turning the picture in space (object-based mental transformation). We suggest that this effect relies on shared functional and cortical mechanisms in the posterior parietal cortex associated with both right anodal GVS and mental imagery.

[Pharmacological correction of central nervous system function in exposure to Coriolis acceleration].

PubMed

Karkishchenko, N N; Dimitriadi, N A; Molchanovskiĭ, V V

1986-01-01

Healthy volunteers with a low vestibular tolerance were exposed to Coriolis acceleration. Potassium orotate, pyracetame and riboxine were used as prophylactic measures against disorders in the function of the vestibular apparatus and higher compartments of the higher nervous system. The central nervous function was assessed with respect to the spectral power of electroencephalograms, short-term memory and mental performance. Potassium orotate given at a dose of 40 mg/kg body weight/day during 12-14 days as well as pyracetame given at a dose of 30 mg/kg body weight/day during 3 or 7 days increased significantly statokinetic tolerance and produced a protective effect on the central nervous function against Coriolis acceleration.

Medial vestibular connections with the hypocretin (orexin) system

NASA Technical Reports Server (NTRS)

Horowitz, Seth S.; Blanchard, Jane; Morin, Lawrence P.

2005-01-01

The mammalian medial vestibular nucleus (MVe) receives input from all vestibular endorgans and provides extensive projections to the central nervous system. Recent studies have demonstrated projections from the MVe to the circadian rhythm system. In addition, there are known projections from the MVe to regions considered to be involved in sleep and arousal. In this study, afferent and efferent subcortical connectivity of the medial vestibular nucleus of the golden hamster (Mesocricetus auratus) was evaluated using cholera toxin subunit-B (retrograde), Phaseolus vulgaris leucoagglutinin (anterograde), and pseudorabies virus (transneuronal retrograde) tract-tracing techniques. The results demonstrate MVe connections with regions mediating visuomotor and postural control, as previously observed in other mammals. The data also identify extensive projections from the MVe to regions mediating arousal and sleep-related functions, most of which receive immunohistochemically identified projections from the lateral hypothalamic hypocretin (orexin) neurons. These include the locus coeruleus, dorsal and pedunculopontine tegmental nuclei, dorsal raphe, and lateral preoptic area. The MVe itself receives a projection from hypocretin cells. CTB tracing demonstrated reciprocal connections between the MVe and most brain areas receiving MVe efferents. Virus tracing confirmed and extended the MVe afferent connections identified with CTB and additionally demonstrated transneuronal connectivity with the suprachiasmatic nucleus and the medial habenular nucleus. These anatomical data indicate that the vestibular system has access to a broad array of neural functions not typically associated with visuomotor, balance, or equilibrium, and that the MVe is likely to receive information from many of the same regions to which it projects.

Vestibular evoked myogenic potential (Vemp): evaluation of responses in normal subjects.

PubMed

Felipe, Lilian; Santos, Marco Aurélio Rocha; Gonçalves, Denise Utsch

2008-01-01

the Vestibular Evoked Myogenic Potential (Vemp) is formed by myogenic neurophysiologic responses activated by high-intensity sound stimulation. The response is registered through surface electromyography of the cervical muscles during muscle contraction. The acoustic stimuli activate the saccular macula, the vestibular inferior nerve and the pathways related to the vestibule-spinal descendant nerves. to describe Vemp parameters in a normal population. thirty adults, 13 men and 17 women with no otoneurological complaints were selected. The stimuli were 200 tone burst, with a frequency of 1Hz and intensity of 118 dB Na, band-pass filter ranging from 10Hz to 1500Hz. The first potential biphasic P13-N23 wave was analyzed. no significant difference was observed between the sides of stimulation in terms of latency and amplitude. However, a statistically significant difference was found for amplitude between genders. Vemp demonstrated to be a reliable instrument in the clinical assessment of the vestibular function.

Plasticity of spontaneous excitatory and inhibitory synaptic activity in morphologically defined vestibular nuclei neurons during early vestibular compensation

PubMed Central

Shao, Mei; Hirsch, June C.

2012-01-01

After unilateral peripheral vestibular lesions, the brain plasticity underlying early recovery from the static symptoms is not fully understood. Principal cells of the chick tangential nucleus offer a subset of morphologically defined vestibular nuclei neurons to study functional changes after vestibular lesions. Chickens show posture and balance deficits immediately after unilateral vestibular ganglionectomy (UVG), but by 3 days most subjects begin to recover, although some remain uncompensated. With the use of whole cell voltage-clamp, spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs) and miniature excitatory and inhibitory postsynaptic currents (mEPSCs and mIPSCs) were recorded from principal cells in brain slices 1 and 3 days after UVG. One day after UVG, sEPSC frequency increased on the lesion side and remained elevated at 3 days in uncompensated chickens only. Also by 3 days, sIPSC frequency increased on the lesion side in all operated chickens due to major increases in GABAergic events. Significant change also occurred in decay time of the events. To determine whether fluctuations in frequency and kinetics influenced overall excitatory or inhibitory synaptic drive, synaptic charge transfer was calculated. Principal cells showed significant increase in excitatory synaptic charge transfer only on the lesion side of uncompensated chickens. Thus compensation continues when synaptic charge transfer is in balance bilaterally. Furthermore, excessive excitatory drive in principal cells on the lesion side may prevent vestibular compensation. Altogether, this work is important for it defines the time course and excitatory and inhibitory nature of changing spontaneous synaptic inputs to a morphologically defined subset of vestibular nuclei neurons during critical early stages of recovery after UVG. PMID:21957228

Vestibular rehabilitation ameliorates chronic dizziness through the SIRT1 axis

PubMed Central

Kao, Chung-Lan; Tsai, Kun-Ling; Cheng, Yuan-Yang; Kuo, Chia-Hua; Lee, Shin-Da; Chan, Rai-Chi

2014-01-01

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 the 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-min 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-γ and PGC-1α) 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. PMID:24624081

Cross-axis adaptation improves 3D vestibulo-ocular reflex alignment during chronic stimulation via a head-mounted multichannel vestibular prosthesis

PubMed Central

Dai, Chenkai; Fridman, Gene Y.; Chiang, Bryce; Davidovics, Natan; Melvin, Thuy-Anh; Cullen, Kathleen E.; Della Santina, Charles C.

2012-01-01

By sensing three-dimensional (3D) head rotation and electrically stimulating the three ampullary branches of a vestibular nerve to encode head angular velocity, a multichannel vestibular prosthesis (MVP) can restore vestibular sensation to individuals disabled by loss of vestibular hair cell function. However, current spread to afferent fibers innervating non-targeted canals and otolith endorgans can distort the vestibular nerve activation pattern, causing misalignment between the perceived and actual axis of head rotation. We hypothesized that over time, central neural mechanisms can adapt to correct this misalignment. To test this, we rendered five chinchillas vestibular-deficient via bilateral gentamicin treatment and unilaterally implanted them with a head mounted MVP. Comparison of 3D angular vestibulo-ocular reflex (aVOR) responses during 2 Hz, 50°/s peak horizontal sinusoidal head rotations in darkness on the first, third and seventh days of continual MVP use revealed that eye responses about the intended axis remained stable (at about 70% of the normal gain) while misalignment improved significantly by the end of one week of prosthetic stimulation. A comparable time course of improvement was also observed for head rotations about the other two semicircular canal axes and at every stimulus frequency examined (0.2–5 Hz). In addition, the extent of disconjugacy between the two eyes progressively improved during the same time window. These results indicate that the central nervous system rapidly adapts to multichannel prosthetic vestibular stimulation to markedly improve 3D aVOR alignment within the first week after activation. Similar adaptive improvements are likely to occur in other species, including humans. PMID:21374081

Adjustment of the dynamic weight distribution as a sensitive parameter for diagnosis of postural alteration in a rodent model of vestibular deficit

PubMed Central

Tighilet, Brahim; Péricat, David; Frelat, Alais; Cazals, Yves; Rastoldo, Guillaume; Boyer, Florent; Dumas, Olivier

2017-01-01

Vestibular disorders, by inducing significant posturo-locomotor and cognitive disorders, can significantly impair the most basic tasks of everyday life. Their precise diagnosis is essential to implement appropriate therapeutic countermeasures. Monitoring their evolution is also very important to validate or, on the contrary, to adapt the undertaken therapeutic actions. To date, the diagnosis methods of posturo-locomotor impairments are restricted to examinations that most often lack sensitivity and precision. In the present work we studied the alterations of the dynamic weight distribution in a rodent model of sudden and complete unilateral vestibular loss. We used a system of force sensors connected to a data analysis system to quantify in real time and in an automated way the weight bearing of the animal on the ground. We show here that sudden, unilateral, complete and permanent loss of the vestibular inputs causes a severe alteration of the dynamic ground weight distribution of vestibulo lesioned rodents. Characteristics of alterations in the dynamic weight distribution vary over time and follow the sequence of appearance and disappearance of the various symptoms that compose the vestibular syndrome. This study reveals for the first time that dynamic weight bearing is a very sensitive parameter for evaluating posturo-locomotor function impairment. Associated with more classical vestibular examinations, this paradigm can considerably enrich the methods for assessing and monitoring vestibular disorders. Systematic application of this type of evaluation to the dizzy or unstable patient could improve the detection of vestibular deficits and allow predicting better their impact on posture and walk. Thus it could also allow a better follow-up of the therapeutic approaches for rehabilitating gait and balance. PMID:29112981

Vision and Vestibular System Dysfunction Predicts Prolonged Concussion Recovery in Children.

PubMed

Master, Christina L; Master, Stephen R; Wiebe, Douglas J; Storey, Eileen P; Lockyer, Julia E; Podolak, Olivia E; Grady, Matthew F

2018-03-01

Up to one-third of children with concussion have prolonged symptoms lasting beyond 4 weeks. Vision and vestibular dysfunction is common after concussion. It is unknown whether such dysfunction predicts prolonged recovery. We sought to determine which vision or vestibular problems predict prolonged recovery in children. A retrospective cohort of pediatric patients with concussion. A subspecialty pediatric concussion program. Four hundred thirty-two patient records were abstracted. Presence of vision or vestibular dysfunction upon presentation to the subspecialty concussion program. The main outcome of interest was time to clinical recovery, defined by discharge from clinical follow-up, including resolution of acute symptoms, resumption of normal physical and cognitive activity, and normalization of physical examination findings to functional levels. Study subjects were 5 to 18 years (median = 14). A total of 378 of 432 subjects (88%) presented with vision or vestibular problems. A history of motion sickness was associated with vestibular dysfunction. Younger age, public insurance, and presence of headache were associated with later presentation for subspecialty concussion care. Vision and vestibular problems were associated within distinct clusters. Provocable symptoms with vestibulo-ocular reflex (VOR) and smooth pursuits and abnormal balance and accommodative amplitude (AA) predicted prolonged recovery time. Vision and vestibular problems predict prolonged concussion recovery in children. A history of motion sickness may be an important premorbid factor. Public insurance status may represent problems with disparities in access to concussion care. Vision assessments in concussion must include smooth pursuits, saccades, near point of convergence (NPC), and accommodative amplitude (AA). A comprehensive, multidomain assessment is essential to predict prolonged recovery time and enable active intervention with specific school accommodations and targeted rehabilitation.

Adjustment of the dynamic weight distribution as a sensitive parameter for diagnosis of postural alteration in a rodent model of vestibular deficit.

PubMed

Tighilet, Brahim; Péricat, David; Frelat, Alais; Cazals, Yves; Rastoldo, Guillaume; Boyer, Florent; Dumas, Olivier; Chabbert, Christian

2017-01-01

Vestibular disorders, by inducing significant posturo-locomotor and cognitive disorders, can significantly impair the most basic tasks of everyday life. Their precise diagnosis is essential to implement appropriate therapeutic countermeasures. Monitoring their evolution is also very important to validate or, on the contrary, to adapt the undertaken therapeutic actions. To date, the diagnosis methods of posturo-locomotor impairments are restricted to examinations that most often lack sensitivity and precision. In the present work we studied the alterations of the dynamic weight distribution in a rodent model of sudden and complete unilateral vestibular loss. We used a system of force sensors connected to a data analysis system to quantify in real time and in an automated way the weight bearing of the animal on the ground. We show here that sudden, unilateral, complete and permanent loss of the vestibular inputs causes a severe alteration of the dynamic ground weight distribution of vestibulo lesioned rodents. Characteristics of alterations in the dynamic weight distribution vary over time and follow the sequence of appearance and disappearance of the various symptoms that compose the vestibular syndrome. This study reveals for the first time that dynamic weight bearing is a very sensitive parameter for evaluating posturo-locomotor function impairment. Associated with more classical vestibular examinations, this paradigm can considerably enrich the methods for assessing and monitoring vestibular disorders. Systematic application of this type of evaluation to the dizzy or unstable patient could improve the detection of vestibular deficits and allow predicting better their impact on posture and walk. Thus it could also allow a better follow-up of the therapeutic approaches for rehabilitating gait and balance.

Procedures for restoring vestibular disorders

PubMed Central

Walther, Leif Erik

2005-01-01

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 (Tab. 1) and 2 (Tab. 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. PMID:22073053

Functional Imaging of Human Vestibular Cortex Activity Elicited by Skull Tap and Auditory Tone Burst

NASA Technical Reports Server (NTRS)

Noohi, Fatemeh; Kinnaird, Catherine; Wood, Scott; Bloomberg, Jacob; Mulavara, Ajitkumar; Seidler, Rachael

2014-01-01

The aim of the current study was to characterize the brain activation in response to two modes of vestibular stimulation: skull tap and auditory tone burst. The auditory tone burst has been used in previous studies to elicit saccular Vestibular Evoked Myogenic Potentials (VEMP) (Colebatch & Halmagyi 1992; Colebatch et al. 1994). Some researchers have reported that airconducted skull tap elicits both saccular and utricle VEMPs, while being faster and less irritating for the subjects (Curthoys et al. 2009, Wackym et al., 2012). However, it is not clear whether the skull tap and auditory tone burst elicit the same pattern of cortical activity. Both forms of stimulation target the otolith response, which provides a measurement of vestibular function independent from semicircular canals. This is of high importance for studying the vestibular disorders related to otolith deficits. Previous imaging studies have documented activity in the anterior and posterior insula, superior temporal gyrus, inferior parietal lobule, pre and post central gyri, inferior frontal gyrus, and the anterior cingulate cortex in response to different modes of vestibular stimulation (Bottini et al., 1994; Dieterich et al., 2003; Emri et al., 2003; Schlindwein et al., 2008; Janzen et al., 2008). Here we hypothesized that the skull tap elicits the similar pattern of cortical activity as the auditory tone burst. Subjects put on a set of MR compatible skull tappers and headphones inside the 3T GE scanner, while lying in supine position, with eyes closed. All subjects received both forms of the stimulation, however, the order of stimulation with auditory tone burst and air-conducted skull tap was counterbalanced across subjects. Pneumatically powered skull tappers were placed bilaterally on the cheekbones. The vibration of the cheekbone was transmitted to the vestibular cortex, resulting in vestibular response (Halmagyi et al., 1995). Auditory tone bursts were also delivered for comparison. To validate our stimulation method, we measured the ocular VEMP outside of the scanner. This measurement showed that both skull tap and auditory tone burst elicited vestibular evoked activation, indicated by eye muscle response. Our preliminary analyses showed that the skull tap elicited activation in medial frontal gyrus, superior temporal gyrus, postcentral gyrus, transverse temporal gyrus, anterior cingulate, and putamen. The auditory tone bursts elicited activation in medial frontal gyrus, superior temporal gyrus, superior frontal gyrus, precentral gyrus, inferior and superior parietal lobules. In line with our hypothesis, skull taps elicited a pattern of cortical activity closely similar to one elicited by auditory tone bursts. Further analysis will determine the extent to which the skull taps can replace the auditory tone stimulation in clinical and basic science vestibular assessments.

Ventral and dorsal streams processing visual motion perception (FDG-PET study)

PubMed Central

2012-01-01

Background Earlier functional imaging studies on visually induced self-motion perception (vection) disclosed a bilateral network of activations within primary and secondary visual cortex areas which was combined with signal decreases, i.e., deactivations, in multisensory vestibular cortex areas. This finding led to the concept of a reciprocal inhibitory interaction between the visual and vestibular systems. In order to define areas involved in special aspects of self-motion perception such as intensity and duration of the perceived circular vection (CV) or the amount of head tilt, correlation analyses of the regional cerebral glucose metabolism, rCGM (measured by fluorodeoxyglucose positron-emission tomography, FDG-PET) and these perceptual covariates were performed in 14 healthy volunteers. For analyses of the visual-vestibular interaction, the CV data were compared to a random dot motion stimulation condition (not inducing vection) and a control group at rest (no stimulation at all). Results Group subtraction analyses showed that the visual-vestibular interaction was modified during CV, i.e., the activations within the cerebellar vermis and parieto-occipital areas were enhanced. The correlation analysis between the rCGM and the intensity of visually induced vection, experienced as body tilt, showed a relationship for areas of the multisensory vestibular cortical network (inferior parietal lobule bilaterally, anterior cingulate gyrus), the medial parieto-occipital cortex, the frontal eye fields and the cerebellar vermis. The “earlier” multisensory vestibular areas like the parieto-insular vestibular cortex and the superior temporal gyrus did not appear in the latter analysis. The duration of perceived vection after stimulus stop was positively correlated with rCGM in medial temporal lobe areas bilaterally, which included the (para-)hippocampus, known to be involved in various aspects of memory processing. The amount of head tilt was found to be positively correlated with the rCGM of bilateral basal ganglia regions responsible for the control of motor function of the head. Conclusions Our data gave further insights into subfunctions within the complex cortical network involved in the processing of visual-vestibular interaction during CV. Specific areas of this cortical network could be attributed to the ventral stream (“what” pathway) responsible for the duration after stimulus stop and to the dorsal stream (“where/how” pathway) responsible for intensity aspects. PMID:22800430

Mild Traumatic Brain Injury and Dynamic Simulated Shooting Performance

DTIC Science & Technology

2016-02-01

for evidence - based criteria for assessing the performance of military personnel after neurosensory (including vestibular) injury. This report...be a compromise between the rifle handling behaviours required of a Soldier and the functional motor coordination activities that are known to be...Some researchers estimate that approximately 90 percent of acute mTBI patients and 80 percent of chronic mTBI patients exhibit evidence of vestibular

The Severity of Vestibular Dysfunction in Deafness as a Determinant of Comorbid Hyperactivity or Anxiety

PubMed Central

McKeehan, Nicholas

2017-01-01

Attention-deficit/hyperactivity disorder (ADHD) and anxiety-related disorders occur at rates 2–3 times higher in deaf compared with hearing children. Potential explanations for these elevated rates and the heterogeneity of behavioral disorders associated with deafness have usually focused on socio-environmental rather than biological effects. Children with the 22q11.2 deletion or duplication syndromes often display hearing loss and behavioral disorders, including ADHD and anxiety-related disorders. Here, we show that mouse mutants with either a gain or loss of function of the T-Box transcription factor gene, Tbx1, which lies within the 22q11.2 region and is responsible for most of the syndromic defects, exhibit inner ear defects and hyperactivity. Furthermore, we show that (1) inner ear dysfunction due to the tissue-specific loss of Tbx1 or Slc12a2, which encodes a sodium-potassium-chloride cotransporter and is also necessary for inner ear function, causes hyperactivity; (2) vestibular rather than auditory failure causes hyperactivity; and (3) the severity rather than the age of onset of vestibular dysfunction differentiates whether hyperactivity or anxiety co-occurs with inner ear dysfunction. Together, these findings highlight a biological link between inner ear dysfunction and behavioral disorders and how sensory abnormalities can contribute to the etiology of disorders traditionally considered of cerebral origin. SIGNIFICANCE STATEMENT This study examines the biological rather than socio-environmental reasons why hyperactivity and anxiety disorders occur at higher rates in deaf individuals. Using conditional genetic approaches in mice, the authors show that (1) inner ear dysfunction due to either Tbx1 or Slc12a2 mutations cause hyperactivity; (2) it is vestibular dysfunction, which frequently co-occurs with deafness but often remains undiagnosed, rather than auditory dysfunction that causes hyperactivity and anxiety-related symptoms; and (3) the severity of vestibular dysfunction can predict whether hyperactivity or anxiety coexist with inner ear dysfunction. These findings suggest a need to evaluate vestibular function in hearing impaired individuals, especially those who exhibit hyperactive and anxiety-related symptoms. PMID:28438970

The Severity of Vestibular Dysfunction in Deafness as a Determinant of Comorbid Hyperactivity or Anxiety.

PubMed

Antoine, Michelle W; Vijayakumar, Sarath; McKeehan, Nicholas; Jones, Sherri M; Hébert, Jean M

2017-05-17

Attention-deficit/hyperactivity disorder (ADHD) and anxiety-related disorders occur at rates 2-3 times higher in deaf compared with hearing children. Potential explanations for these elevated rates and the heterogeneity of behavioral disorders associated with deafness have usually focused on socio-environmental rather than biological effects. Children with the 22q11.2 deletion or duplication syndromes often display hearing loss and behavioral disorders, including ADHD and anxiety-related disorders. Here, we show that mouse mutants with either a gain or loss of function of the T-Box transcription factor gene, Tbx1 , which lies within the 22q11.2 region and is responsible for most of the syndromic defects, exhibit inner ear defects and hyperactivity. Furthermore, we show that (1) inner ear dysfunction due to the tissue-specific loss of Tbx1 or Slc12a2 , which encodes a sodium-potassium-chloride cotransporter and is also necessary for inner ear function, causes hyperactivity; (2) vestibular rather than auditory failure causes hyperactivity; and (3) the severity rather than the age of onset of vestibular dysfunction differentiates whether hyperactivity or anxiety co-occurs with inner ear dysfunction. Together, these findings highlight a biological link between inner ear dysfunction and behavioral disorders and how sensory abnormalities can contribute to the etiology of disorders traditionally considered of cerebral origin. SIGNIFICANCE STATEMENT This study examines the biological rather than socio-environmental reasons why hyperactivity and anxiety disorders occur at higher rates in deaf individuals. Using conditional genetic approaches in mice, the authors show that (1) inner ear dysfunction due to either Tbx1 or Slc12a2 mutations cause hyperactivity; (2) it is vestibular dysfunction, which frequently co-occurs with deafness but often remains undiagnosed, rather than auditory dysfunction that causes hyperactivity and anxiety-related symptoms; and (3) the severity of vestibular dysfunction can predict whether hyperactivity or anxiety coexist with inner ear dysfunction. These findings suggest a need to evaluate vestibular function in hearing impaired individuals, especially those who exhibit hyperactive and anxiety-related symptoms. Copyright © 2017 the authors 0270-6474/17/375144-11$15.00/0.

Influences of Vestibular System on Sympathetic Nervous System. Implications for countermeasures.

NASA Astrophysics Data System (ADS)

Denise, Pr Pierre

As gravity is a direct and permanent stress on body fluids, muscles and bones, it is not surpris-ing that weightlessness has important effects on cardiovascular and musculo-skeletal systems. However, these harmful effects do not totally result from the removal of the direct stress of gravity on these organs, but are also partially and indirectly mediated by the vestibular sys-tem. Besides its well known crucial role in spatial orientation and postural equilibrium, it is now clear that the vestibular system is also involved in the regulation of other important physi-ological systems: respiratory and cardiovascular systems, circadian regulation, food intake and even bone mineralization. The neuroanatomical substrate for these vestibular-mediated reg-ulations is still poorly defined, but there is much evidence that vestibular system has strong impacts not only on brainstem autonomic centers but on many hypothalamic nuclei as well. As autonomic nervous system controls almost all body organs, bringing into play the vestibular system by hypergravity or microgravity could virtually affects all major physiological func-tions. There is experimental evidence that weightlessness as well as vestibular lesion induce sympathetic activation thus participating in space related physiological alterations. The fact that some effects of weightlessness on biological systems are mediated by the vestibular system has an important implication for using artificial gravity as a countermeasure: artificial gravity should load not only bones and the cardiovascular system but the vestibular system as well. In short-arm centrifuges, the g load at the head level is low because the head is near the axis of rotation. If the vestibular system is involved in cardiovascular deconditioning and bone loss during weightlessness, it would be more effective to significantly stimulate it and thus it would be necessary to place the head off-axis. Moreover, as the otolithic organs are non longer stimu-lated in term of gravity during space flight, and because of the plasticity of the brain, it might be possible that their inputs be progressively interpreted as resulting from translational move-ment with no gravity related activation. Therefore, on return to Earth the effect of the otoliths on cardiovascular regulation might be temporarily lost leading to orthostatic intolerance.

Role of orientation reference selection in motion sickness

NASA Technical Reports Server (NTRS)

Peterka, Robert J.; Black, F. Owen

1988-01-01

Previous experiments with moving platform posturography have shown that different people have varying abilities to resolve conflicts among vestibular, visual, and proprioceptive sensory signals used to control upright posture. In particular, there is one class of subjects with a vestibular disorder known as benign paroxysmal positional vertigo (BPPV) who often are particularly sensitive to inaccurate visual information. That is, they will use visual sensory information for the control of their posture even when that visual information is inaccurate and is in conflict with accurate proprioceptive and vestibular sensory signals. BPPV has been associated with disorders of both posterior semicircular canal function and possibly otolith function. The present proposal hopes to take advantage of the similarities between the space motion sickness problem and the sensory orientation reference selection problems associated with the BPPV syndrome. These similarities include both etiology related to abnormal vertical canal-otolith function, and motion sickness initiating events provoked by pitch and roll head movements. The objectives of this proposal are to explore and quantify the orientation reference selection abilities of subjects and the relation of this selection to motion sickness in humans.

Representation of visual gravitational motion in the human vestibular cortex.

PubMed

Indovina, Iole; Maffei, Vincenzo; Bosco, Gianfranco; Zago, Myrka; Macaluso, Emiliano; Lacquaniti, Francesco

2005-04-15

How do we perceive the visual motion of objects that are accelerated by gravity? We propose that, because vision is poorly sensitive to accelerations, an internal model that calculates the effects of gravity is derived from graviceptive information, is stored in the vestibular cortex, and is activated by visual motion that appears to be coherent with natural gravity. The acceleration of visual targets was manipulated while brain activity was measured using functional magnetic resonance imaging. In agreement with the internal model hypothesis, we found that the vestibular network was selectively engaged when acceleration was consistent with natural gravity. These findings demonstrate that predictive mechanisms of physical laws of motion are represented in the human brain.

Short latency vestibular evoked potentials in the Japanese quail (Coturnix coturnix japonica)

NASA Technical Reports Server (NTRS)

Jones, S. M.; Jones, T. A.; Shukla, R.

1997-01-01

Short-latency vestibular-evoked potentials to pulsed linear acceleration were characterized in the quail. Responses occurred within 8 ms following the onset of stimuli and were composed of a series of positive and negative peaks. The latencies and amplitudes of the first four peaks were quantitatively characterized. Mean latencies at 1.0 g ms-1 ranged from 1265 +/- 208 microseconds (P1, N = 18) to 4802 +/- 441 microseconds (N4, N = 13). Amplitudes ranged from 3.72 +/- 1.51 microV (P1/N1, N = 18) to 1.49 +/- 0.77 microV (P3/N3, N = 16). Latency-intensity (LI) slopes ranged from -38.7 +/- 7.3 microseconds dB-1 (P1, N = 18) to -71.6 +/- 21.9 microseconds dB-1 (N3, N = 15) and amplitude-intensity (AI) slopes ranged from 0.20 +/- 0.08 microV dB-1 (P1/N1, N = 18) to 0.07 +/- 0.04 microV dB-1 (P3/N3, N = 11). The mean response threshold across all animals was -21.83 +/- 3.34 dB re: 1.0 g ms-1 (N = 18). Responses remained after cochlear extirpation showing that they could not depend critically on cochlear activity. Responses were eliminated by destruction of the vestibular end organs, thus showing that responses depended critically and specifically on the vestibular system. The results demonstrate that the responses are vestibular and the findings provide a scientific basis for using vestibular responses to evaluate vestibular function through ontogeny and senescence in the quail.

Magnetic vestibular stimulation modulates default mode network fluctuations.

PubMed

Boegle, Rainer; Stephan, Thomas; Ertl, Matthias; Glasauer, Stefan; Dieterich, Marianne

2016-02-15

Strong magnetic fields (>1 Tesla) can cause dizziness and it was recently shown that healthy subjects (resting in total darkness) developed a persistent nystagmus even when remaining completely motionless within a MR tomograph. Consequently, it was speculated that this magnetic vestibular stimulation (MVS) might influence fMRI results, as nystagmus is indicative of an imbalance in the vestibular system, potentially influencing other systems via multisensory vestibular interactions. The objective of our study was to investigate whether MVS does indeed modulate BOLD signal fluctuations. We recorded eye movements, as well as, resting-state fMRI of 30 volunteers in darkness at 1.5 T and 3.0 T to answer the question whether MVS modulated parts of the default mode resting-state network (DMN) in accordance with the Lorentz-force model for MVS, while distinguishing this from the known signal increase due to field strength related imaging effects. Our results showed that modulation of the default mode network occurred mainly in areas associated with vestibular and ocular motor function, and was in accordance with the Lorentz-force model, i.e., double than the expected signal scaling due to field strength alone. We discuss the implications of our findings for the interpretation of studies using resting-state fMRI, especially those concerning vestibular research. We conclude that MVS needs to be considered in vestibular research to avoid biased results, but it might also offer the possibility of manipulating network dynamics and may thus help in studying the brain as a dynamical system. Copyright © 2015 Elsevier Inc. All rights reserved.

Validation of the Italian Version of the Dizziness Handicap Inventory, the Situational Vertigo Questionnaire, and the Activity-Specific Balance Confidence Scale for Peripheral and Central Vestibular Symptoms.

PubMed

Colnaghi, Silvia; Rezzani, Cristiana; Gnesi, Marco; Manfrin, Marco; Quaglieri, Silvia; Nuti, Daniele; Mandalà, Marco; Monti, Maria Cristina; Versino, Maurizio

2017-01-01

Neurophysiological measurements of the vestibular function for diagnosis and follow-up evaluations provide an objective assessment, which, unfortunately, does not necessarily correlate with the patients' self-feeling. The literature provides many questionnaires to assess the outcome of rehabilitation programs for disequilibrium, but only for the Dizziness Handicap Inventory (DHI) is an Italian translation available, validated on a small group of patients suffering from a peripheral acute vertigo. We translated and validated the reliability and validity of the DHI, the Situational Vertigo Questionnaire (SVQ), and the Activities-Specific Balance Confidence Scale (ABC) in 316 Italian patients complaining of dizziness due either to a peripheral or to a central vestibular deficit, or in whom vestibular signs were undetectable by means of instrumental testing or clinical evaluation. Cronbach's coefficient alpha, the homogeneity index, and test-retest reproducibility, confirmed reliability of the Italian version of the three questionnaires. Validity was confirmed by correlation test between questionnaire scores. Correlations with clinical variables suggested that they can be used as a complementary tool for the assessment of vestibular symptoms. In conclusion, the Italian versions of DHI, SVQ, and ABC are reliable and valid questionnaires for assessing the impact of dizziness on the quality of life of Italian patients with peripheral or central vestibular deficit.

Effect of low level laser (LLL) on cochlear and vestibular inner ear including tinnitus

NASA Astrophysics Data System (ADS)

Rhee, Chung-Ku; Lim, Eun-Seok; Kim, Young-Saeng; Chung, Yong-Won; Jung, Jae-Yun; Chung, Phil-Sang

2006-02-01

Objectives: 1. To investigate preventive effect of LLL on gentamicin-induced vestibular ototoxicity. 2. To evaluate the effectiveness of lower level laser (LLL) in the treatment of tinnitus. Methods: 1. Twenty guinea pigs were divided into control and laser groups. Vestibular ototoxicity was induced by intratympanic injection of gentamicin into left ear. LLL was irradiated into left ear canal of animals in laser group. Vestibular function of the animals was evaluated with vertical and off-vertical axis rotation testing. 2. Forty patients with tinnitus were treated with ginkgo biloba orally and randomly divided into control and laser groups. The 20 patients of laser group received 80.4 J/cm2 of 830 nm laser, 3 times per week for 4 weeks, via transmeatal irradiation. Tinnitus was evaluated by visual analogue scale (VAS) and tinnitus handicap inventory (THI). Results: 1. Preventive effect of LLL to gentamicin induced vestibular ototoxicity was demonstrated by preventing reduction of gain in slow harmonic acceleration test and modulation in the off-vertical axis rotation test. 2. Eleven of 20 laser group patients have shown significant improvement in VAS and THI compared to those of the control group. Conclusions: 1. LLL therapy may have preventive effect to vestibular ototoxicity. 2. LLL therapy in combination with ginkgo biloba seems to be worth trying on patients with tinnitus.

Validation of the Italian Version of the Dizziness Handicap Inventory, the Situational Vertigo Questionnaire, and the Activity-Specific Balance Confidence Scale for Peripheral and Central Vestibular Symptoms

PubMed Central

Colnaghi, Silvia; Rezzani, Cristiana; Gnesi, Marco; Manfrin, Marco; Quaglieri, Silvia; Nuti, Daniele; Mandalà, Marco; Monti, Maria Cristina; Versino, Maurizio

2017-01-01

Neurophysiological measurements of the vestibular function for diagnosis and follow-up evaluations provide an objective assessment, which, unfortunately, does not necessarily correlate with the patients’ self-feeling. The literature provides many questionnaires to assess the outcome of rehabilitation programs for disequilibrium, but only for the Dizziness Handicap Inventory (DHI) is an Italian translation available, validated on a small group of patients suffering from a peripheral acute vertigo. We translated and validated the reliability and validity of the DHI, the Situational Vertigo Questionnaire (SVQ), and the Activities-Specific Balance Confidence Scale (ABC) in 316 Italian patients complaining of dizziness due either to a peripheral or to a central vestibular deficit, or in whom vestibular signs were undetectable by means of instrumental testing or clinical evaluation. Cronbach’s coefficient alpha, the homogeneity index, and test–retest reproducibility, confirmed reliability of the Italian version of the three questionnaires. Validity was confirmed by correlation test between questionnaire scores. Correlations with clinical variables suggested that they can be used as a complementary tool for the assessment of vestibular symptoms. In conclusion, the Italian versions of DHI, SVQ, and ABC are reliable and valid questionnaires for assessing the impact of dizziness on the quality of life of Italian patients with peripheral or central vestibular deficit. PMID:29066999

Impaired math achievement in patients with acute vestibular neuritis.

PubMed

Moser, Ivan; Vibert, Dominique; Caversaccio, Marco D; Mast, Fred W

2017-12-01

Broad cognitive difficulties have been reported in patients with peripheral vestibular deficit, especially in the domain of spatial cognition. Processing and manipulating numbers relies on the ability to use the inherent spatial features of numbers. It is thus conceivable that patients with acute peripheral vestibular deficit show impaired numerical cognition. Using the number Stroop task and a short math achievement test, we tested 20 patients with acute vestibular neuritis and 20 healthy, age-matched controls. On the one hand, patients showed normal congruency and distance effects in the number Stroop task, which is indicative of normal number magnitude processing. On the other hand, patients scored lower than healthy controls in the math achievement test. We provide evidence that the lower performance cannot be explained by either differences in prior math knowledge (i.e., education) or slower processing speed. Our results suggest that peripheral vestibular deficit negatively affects numerical cognition in terms of the efficient manipulation of numbers. We discuss the role of executive functions in math performance and argue that previously reported executive deficits in patients with peripheral vestibular deficit provide a plausible explanation for the lower math achievement scores. In light of the handicapping effects of impaired numerical cognition in daily living, it is crucial to further investigate the mechanisms that cause mathematical deficits in acute PVD and eventually develop adequate means for cognitive interventions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Estimation of Optimum Stimulus Amplitude for Balance Training using Electrical Stimulation of the Vestibular System

NASA Technical Reports Server (NTRS)

Goel, R.; Rosenberg, M. J.; De Dios, Y. E.; Cohen, H. S.; Bloomberg, J. J.; Mulavara, A. P.

2016-01-01

Sensorimotor changes such as posture and gait instabilities can affect the functional performance of astronauts after gravitational transitions. Sensorimotor Adaptability (SA) training can help alleviate decrements on exposure to novel sensorimotor environments based on the concept of 'learning to learn' by exposure to varying sensory challenges during posture and locomotion tasks (Bloomberg 2015). Supra-threshold Stochastic Vestibular Stimulation (SVS) can be used to provide one of many challenges by disrupting vestibular inputs. In this scenario, the central nervous system can be trained to utilize veridical information from other sensory inputs, such as vision and somatosensory inputs, for posture and locomotion control. The minimum amplitude of SVS to simulate the effect of deterioration in vestibular inputs for preflight training or for evaluating vestibular contribution in functional tests in general, however, has not yet been identified. Few studies (MacDougall 2006; Dilda 2014) have used arbitrary but fixed maximum current amplitudes from 3 to 5 mA in the medio-lateral (ML) direction to disrupt balance function in healthy adults. Giving this high level of current amplitude to all the individuals has a risk of invoking side effects such as nausea and discomfort. The goal of this study was to determine the minimum SVS level that yields an equivalently degraded balance performance. Thirteen subjects stood on a compliant foam surface with their eyes closed and were instructed to maintain a stable upright stance. Measures of stability of the head, trunk, and whole body were quantified in the ML direction. Duration of time they could stand on the foam surface was also measured. The minimum SVS dosage was defined to be that level which significantly degraded balance performance such that any further increase in stimulation level did not lead to further balance degradation. The minimum SVS level was determined by performing linear fits on the performance variable at different stimulation levels. Results from the balance task suggest that there are inter-individual differences and the minimum SVS amplitude was found to be in the range of 1 mA to 2.5 mA across subjects. SVS resulted in an average decrement of balance task performance in the range of 62%-73% across different measured variables at the minimum SVS amplitude in comparison to the control trial (no stimulus). Training using supra-threshold SVS stimulation is one of the sensory challenges used for preflight SA training designed to improve adaptability to novel gravitational environments. Inter-individual differences in response to SVS can help customize the SA training paradigms using minimal dosage required. Another application of using SVS is to simulate acute deterioration of vestibular sensory inputs in the evaluation of tests for assessing vestibular function.

Loss of otolith function with age is associated with increased postural sway measures.

PubMed

Serrador, Jorge M; Lipsitz, Lewis A; Gopalakrishnan, Gosala S; Black, F Owen; Wood, Scott J

2009-11-06

Loss of balance and increased fall risk is a common problem associated with aging. Changes in vestibular function occur with aging but the contribution of reduced vestibular otolith function to fall risk remains unknown. We examined a population of 151 healthy individuals (aged 21-93) for both balance (sway measures) and ocular counter-rolling (OCR) function. We assessed balance function with eyes open and closed on a firm surface, eyes open and closed on a foam surface and OCR during +/-20 degree roll tilt at 0.005 Hz. Subjects demonstrated a significant age-related reduction in OCR and increase in postural sway. The effect of age on OCR was greater in females than males. The reduction in OCR was strongly correlated with the mediolateral measures of sway with eyes closed. This correlation was also present in the elderly group alone, suggesting that aging alone does not account for this effect. OCR decreased linearly with age and at a greater rate in females than males. This loss of vestibular otolith-ocular function is associated with increased mediolateral measures of sway which have been shown to be related to increased risk of falls. These data suggest a role for loss of otolith function in contributing to fall risk in the elderly. Further prospective, longitudinal studies are necessary to confirm these findings.

Are Covert Saccade Functionally Relevant in Vestibular Hypofunction?

PubMed

Hermann, R; Pelisson, D; Dumas, O; Urquizar, Ch; Truy, E; Tilikete, C

2018-06-01

The vestibulo-ocular reflex maintains gaze stabilization during angular or linear head accelerations, allowing adequate dynamic visual acuity. In case of bilateral vestibular hypofunction, patients use saccades to compensate for the reduced vestibulo-ocular reflex function, with covert saccades occurring even during the head displacement. In this study, we questioned whether covert saccades help maintain dynamic visual acuity, and evaluated which characteristic of these saccades are the most relevant to improve visual function. We prospectively included 18 patients with chronic bilateral vestibular hypofunction. Subjects underwent evaluation of dynamic visual acuity in the horizontal plane as well as video recording of their head and eye positions during horizontal head impulse tests in both directions (36 ears tested). Frequency, latency, consistency of covert saccade initiation, and gain of covert saccades as well as residual vestibulo-ocular reflex gain were calculated. We found no correlation between residual vestibulo-ocular reflex gain and dynamic visual acuity. Dynamic visual acuity performance was however positively correlated with the frequency and gain of covert saccades and negatively correlated with covert saccade latency. There was no correlation between consistency of covert saccade initiation and dynamic visual acuity. Even though gaze stabilization in space during covert saccades might be of very short duration, these refixation saccades seem to improve vision in patients with bilateral vestibular hypofunction during angular head impulses. These findings emphasize the need for specific rehabilitation technics that favor the triggering of covert saccades. The physiological origin of covert saccades is discussed.

The long-term consequences of the exposure to increasing gravity levels on the muscular, vestibular and cognitive functions in adult mice.

PubMed

Bojados, Mickael; Jamon, Marc

2014-05-01

Adult male mice C57Bl6/J were exposed to gravity levels between 1G and 4G during three weeks, and the long-term consequences on muscular, vestibular, emotional, and cognitive abilities were evaluated at the functional level to test the hypothesis of a continuum in the response to the increasing gravitational force. In agreement with the hypothesis, the growth of body mass slowed down in relation with the gravity level during the centrifugation, and weight recovery was inversely proportional. On the other hand, the long-term consequences on muscular, vestibular, emotional, and cognitive abilities did not fit the hypothesis of a continuum in the response to the gravity level. The hypergravity acted as endurance training on muscle force until 3G, then became deleterious at 4G. The vestibular reactions were not affected until 4G. Persistent emotional reactions appeared at 3G, and particularly 4G. The mice centrifuged at 3G and 4G showed an impaired spatial learning, probably in relation with the increased level of anxiety, but a greater difficulty was also observed in mice exposed at 2G, suggesting another cause for the impairment of spatial memory. The long-term response to the hypergravity was shown to depend on both the level of gravity and the duration of exposition, with different importance depending on the function considered. Copyright © 2014 Elsevier B.V. All rights reserved.

Vestibular functions and sleep in space experiments. [using rhesus and owl monkeys

NASA Technical Reports Server (NTRS)

Perachio, A. A.

1977-01-01

Physical indices of sleep were continuously monitored in an owl monkey living in a chamber continuously rotating at a constant angular velocity. The electrophysiological data obtained from chronically implanted electrodes was analyzed to determine the chronic effects of vestibular stimulation on sleep and wakefulness cycles. The interaction of linear and angular acceleration on the vestibulo-ocular reflex was investigated in three rhesus monkeys at various angular accelerations.

Space Flight and Manual Control: Implications for Sensorimotor Function on Future Missions

NASA Technical Reports Server (NTRS)

Reschke, Millard F.; Kornilova, Ludmila; Tomilovskaya, Elena; Parker, Donald E.; Leigh, R. John; Kozlovskaya, Inessa

2009-01-01

Control of vehicles, and other complex mechanical motion systems, is a high-level integrative function of the central nervous system (CNS) that requires good visual acuity, eye-hand coordination, spatial (and, in some cases, geographic) orientation perception, and cognitive function. Existing evidence from space flight research (Paloski et.al., 2008, Clement and Reschke 2008, Reschke et al., 2007) demonstrates that the function of each of these systems is altered by removing (and subsequently by reintroducing) a gravitational field that can be sensed by vestibular, proprioceptive, and haptic receptors and used by the CNS for spatial orientation, navigation, and coordination of movements. Furthermore, much of the operational performance data collected as a function of space flight has not been available for independent analysis, and those data that have been reviewed are equivocal owing to uncontrolled environmental and/or engineering factors. Thus, our current understanding, when it comes to manual control, is limited primarily to a review of those situations where manual control has been a factor. One of the simplest approaches to the manual control problem is to review shuttle landing data. See the Figure below for those landing for which we have Shuttle velocities over the runway threshold.

Study of adaptation to altered gravity through systems analysis of motor control.

PubMed

Fox, R A; Daunton, N G; Corcoran, M L

1998-01-01

Maintenance of posture and production of functional, coordinated movement demand integration of sensory feedback with spinal and supra-spinal circuitry to produce adaptive motor control in altered gravity (G). To investigate neuroplastic processes leading to optimal performance in altered G we have studied motor control in adult rats using a battery of motor function tests following chronic exposure to various treatments (hyper-G, hindlimb suspension, chemical distruction of hair cells, space flight). These treatments differentially affect muscle fibers, vestibular receptors, and behavioral compensations and, in consequence, differentially disrupt air righting, swimming, posture and gait. The time-course of recovery from these disruptions varies depending on the function tested and the duration and type of treatment. These studies, with others (e.g., D'Amelio et al. in this volume), indicate that adaptation to altered gravity involves alterations in multiple sensory-motor systems that change at different rates. We propose that the use of parallel studies under different altered G conditions will most efficiently lead to an understanding of the modifications in central (neural) and peripheral (sensory and neuromuscular) systems that underlie sensory-motor adaptation in active, intact individuals.

Study of adaptation to altered gravity through systems analysis of motor control

NASA Astrophysics Data System (ADS)

Fox, R. A.; Daunton, N. G.; Corcoran, M. L.

Maintenance of posture and production of functional, coordinated movement demand integration of sensory feedback with spinal and supra-spinal circuitry to produce adaptive motor control in altered gravity (G). To investigate neuroplastic processes leading to optimal performance in altered G we have studied motor control in adult rats using a battery of motor function tests following chronic exposure to various treatments (hyper-G, hindlimb suspension, chemical distruction of hair cells, space flight). These treatments differentially affect muscle fibers, vestibular receptors, and behavioral compensations and, in consequence, differentially disrupt air righting, swimming, posture and gait. The time-course of recovery from these disruptions varies depending on the function tested and the duration and type of treatment. These studies, with others (e.g., D'Amelio et al. in this volume), indicate that adaptation to altered gravity involves alterations in multiple sensory-motor systems that change at different rates. We propose that the use of parallel studies under different altered G conditions will most efficiently lead to an understanding of the modifications in central (neural) and peripheral (sensory and neuromuscular) systems that underlie sensory-motor adaptation in active, intact individuals.

Effect of Vestibular Impairment on Cerebral Blood Flow Response to Dynamic Roll Tilt

NASA Technical Reports Server (NTRS)

Serrador, J. M.; Black, F. O.; Schlgel, Todd T.; Lipsitz, L. A.; Wood, S. J.

2008-01-01

Change to upright posture results in reductions in cerebral perfusion pressure due to hydrostatic pressure changes related to gravity. Since vestibular organs, specifically the otoliths, provide information on position relative to gravity, vestibular inputs may assist in adaptation to the upright posture. The goal of this study was to examine the effect of direct vestibular stimulation on cerebral blood flow (CBF). To examine the role of otolith inputs we screened 165 subjects for vestibular function and classified subjects as either normal or impaired based on ocular torsion. Ocular torsion, an indication of otolith function, was assessed during sinusoidal roll tilt of 20 degrees at 0.01 Hz (100 sec per cycle). Subjects with torsion one SD below the mean were classified as impaired while subjects one SD above the mean were considered normal. During one session subjects were placed in a chair that was sinusoidally rotated 25 degrees in the roll plane at five frequencies: 0.25 & 0.125 Hz for 80 sec, 0.0625 Hz for 160 sec and 0.03125 Hz and 0.015625 Hz for 320 sec. During testing, CBF (transcranial Doppler), blood pressure (Finapres), and end tidal CO2 (Puritan Bennet) were measured continuously. Ocular torsion was assessed from infrared images of the eyes. All rotations were done in the dark with subjects fixated on a red LED directly at the center of rotation. In the normal group, dynamic tilt resulted in significant changes in both blood pressure and cerebral blood flow velocity that was related to the frequency of stimulus. In contrast the impaired group did not show similar patterns. As expected normal subjects demonstrated significant ocular torsion that was related to stimulus frequency while impaired subjects had minimal changes. These data suggest that vestibular inputs have direct effects on cerebral blood flow regulation during dynamic tilt. Supported by NASA.

Difference in quick phases induced by horizontal and vertical vestibular stimulations: role of the otolithic input.

PubMed

Pettorossi, V E; Errico, P; Ferraresi, A

1997-01-01

Quick phases (QPs) induced by horizontal and vertical sinusoidal vestibular stimulations were studied in rabbits, cats, and humans. In all the animals, large and frequent horizontal QPs were observed following yaw stimulation in prone position. By contrast, QPs were almost absent during roll stimulation in rabbits, and they were small and oblique during pitch stimulation in cats and humans. As a result of these differences, the range of gaze displacement induced by vestibular stimulations was greater in the horizontal plane than in the vertical one. We also found that the trajectory of the QPs in rabbits was kept horizontal even when the yaw rotation was off vertical axis of +/- 45 degrees in the sagittal plane. Moreover, in the rabbit, the rare horizontal QPs induced by roll stimulation did not change their orientation at various pitch angles of roll stimulation axis. The QPs were also analyzed following roll stimulation of the rabbit in supine position. In this condition, in which the otolithic receptors were activated in the opposite way compared to prone position, large vertical QPs were elicited. We concluded that these results provide evidence that the otolithic signal plays a role in controlling occurrence and trajectory orientation of the QPs.

Application of multivariate statistics to vestibular testing: discriminating between Meniere's disease and migraine associated dizziness

NASA Technical Reports Server (NTRS)

Dimitri, P. S.; Wall, C. 3rd; Oas, J. G.; Rauch, S. D.

2001-01-01

Meniere's disease (MD) and migraine associated dizziness (MAD) are two disorders that can have similar symptomatologies, but differ vastly in treatment. Vestibular testing is sometimes used to help differentiate between these disorders, but the inefficiency of a human interpreter analyzing a multitude of variables independently decreases its utility. Our hypothesis was that we could objectively discriminate between patients with MD and those with MAD using select variables from the vestibular test battery. Sinusoidal harmonic acceleration test variables were reduced to three vestibulo-ocular reflex physiologic parameters: gain, time constant, and asymmetry. A combination of these parameters plus a measurement of reduced vestibular response from caloric testing allowed us to achieve a joint classification rate of 91%, independent quadratic classification algorithm. Data from posturography were not useful for this type of differentiation. Overall, our classification function can be used as an unbiased assistant to discriminate between MD and MAD and gave us insight into the pathophysiologic differences between the two disorders.

Allicin protects against cisplatin-induced vestibular dysfunction by inhibiting the apoptotic pathway.

PubMed

Wu, Xianmin; Cai, Jing; Li, Xiaofei; Li, He; Li, Jianfeng; Bai, Xiaohui; Liu, Wenwen; Han, Yuechen; Xu, Lei; Zhang, Daogong; Wang, Haibo; Fan, Zhaomin

2017-06-15

Cisplatin is an anticancer drug that causes the impairment of inner ear function as side effects, including hearing loss and balance dysfunction. The purpose of this study was to investigate the effects of allicin against cisplatin-induced vestibular dysfunction in mice and to make clear the mechanism underlying the protective effects of allicin on oto-vestibulotoxicity. Mice intraperitoneally injected with cisplatin exhibited vestibular dysfunction in swimming test, which agreed with impairment in vestibule. However, these impairments were significantly prevented by pre-treatment with allicin. Allicin markedly reduced cisplatin-activated expression of cleaved-caspase-3 in hair cells and vascular layer cells of utricule, saccule and ampulla, but also decreased AIF nuclear translocation of hair cells in utricule, saccule and ampulla. These results showed that allicin played an effective role in protecting vestibular dysfunction induced by cisplatin via inhibiting caspase-dependent and caspase-independent apoptotic pathways. Therefore, allicin may be useful in preventing oto-vestibulotoxicity mediated by cisplatin. Copyright © 2017. Published by Elsevier B.V.

Relationships Between Vestibular Measures as Potential Predictors for Spaceflight Sensorimotor Adaptation

NASA Technical Reports Server (NTRS)

Clark, T. K.; Peters, B.; Gadd, N. E.; De Dios, Y. E.; Wood, S.; Bloomberg, J. J.; Mulavara, A. P.

2016-01-01

Introduction: During space exploration missions astronauts are exposed to a series of novel sensorimotor environments, requiring sensorimotor adaptation. Until adaptation is complete, sensorimotor decrements occur, affecting critical tasks such as piloted landing or docking. Of particularly interest are locomotion tasks such as emergency vehicle egress or extra-vehicular activity. While nearly all astronauts eventually adapt sufficiently, it appears there are substantial individual differences in how quickly and effectively this adaptation occurs. These individual differences in capacity for sensorimotor adaptation are poorly understood. Broadly, we aim to identify measures that may serve as pre-flight predictors of and individual's adaptation capacity to spaceflight-induced sensorimotor changes. As a first step, since spaceflight is thought to involve a reinterpretation of graviceptor cues (e.g. otolith cues from the vestibular system) we investigate the relationships between various measures of vestibular function in humans. Methods: In a set of 15 ground-based control subjects, we quantified individual differences in vestibular function using three measures: 1) ocular vestibular evoked myogenic potential (oVEMP), 2) computerized dynamic posturography and 3) vestibular perceptual thresholds. oVEMP responses are elicited using a mechanical stimuli approach. Computerized dynamic posturography was used to quantify Sensory Organization Tests (SOTs), including SOT5M which involved performing pitching head movements while balancing on a sway-reference support surface with eyes closed. We implemented a vestibular perceptual threshold task using the tilt capabilities of the Tilt-Translation Sled (TTS) at JSC. On each trial, the subject was passively roll-tilted left ear down or right ear down in the dark and verbally provided a forced-choice response regarding which direction they felt tilted. The motion profile was a single-cycle sinusoid of angular acceleration with a duration of 5 seconds (frequency of 0.2 Hz), which was selected as it requires sensory integration of otolith and semicircular canal cues. Stimuli direction was randomized and magnitude was determined using an adaptive sampling procedure. One hundred trials were provided and each subject's responses were fit with a psychometric curve to estimate the subject's threshold. Results: Roll tilt perceptual thresholds at 0.2 Hz ranged from 0.5 degrees to 1.82 degrees across the 15 subjects (geometric mean of 1.04 degrees), consistent with previous studies. The inter-individual variability in thresholds may be able to help explain individual differences observed in sensorimotor adaptation to spaceflight. Analysis is ongoing for the oVEMPS and computerized dynamic posturography to identify relationships between the various vestibular measures. Discussion: Predicting individual differences in sensorimotor adaptation is critical both for the development of personalized countermeasures and mission planning. Here we aim to develop a basis of vestibular tests and parameters which may serve as predictors of individual differences in sensorimotor adaptability through studying the relationship between these measures.

[Vestibular compensation studies]. [Vestibular Compensation and Morphological Studies

NASA Technical Reports Server (NTRS)

Perachio, Adrian A. (Principal Investigator)

1996-01-01

The following topics are reported: neurophysiological studies on MVN neurons during vestibular compensation; effects of spinal cord lesions on VNC neurons during compensation; a closed-loop vestibular compensation model for horizontally canal-related MVN neurons; spatiotemporal convergence in VNC neurons; contributions of irregularly firing vestibular afferents to linear and angular VOR's; application to flight studies; metabolic measures in vestibular neurons; immediate early gene expression following vestibular stimulation; morphological studies on primary afferents, central vestibular pathways, vestibular efferent projection to the vestibular end organs, and three-dimensional morphometry and imaging.

iss051e049152

NASA Image and Video Library

2017-05-24

iss051e049152 (5/24/2017) --- ESA astronaut Thomas Pesquet performs the commissioning of the Gravitational References for Sensimotor Performance (GRASP) experiment, to better understand how the central nervous system (CNS) integrates information from different sensations. The data collected could help researchers better understand the workings of the human vestibular system and how it connects to the other sensory organs. This research hopes to shed light on how to best treat the loss of vestibular function on Earth.

iss051e049147

NASA Image and Video Library

2017-05-24

iss051e049147 (5/24/2017) --- ESA astronaut Thomas Pesquet performs the commissioning of the Gravitational References for Sensimotor Performance (GRASP) experiment, to better understand how the central nervous system (CNS) integrates information from different sensations. The data collected could help researchers better understand the workings of the human vestibular system and how it connects to the other sensory organs. This research hopes to shed light on how to best treat the loss of vestibular function on Earth.

Experiment M131. Human vestibular function

NASA Technical Reports Server (NTRS)

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

1977-01-01

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.

Multimodal Integration After Unilateral Labyrinthine Lesion: Single Vestibular Nuclei Neuron Responses and Implications for Postural Compensation

PubMed Central

Sadeghi, Soroush G.; Minor, Lloyd B.

2011-01-01

Plasticity in neuronal responses is necessary for compensation following brain lesions and adaptation to new conditions and motor learning. In a previous study, we showed that compensatory changes in the vestibuloocular reflex (VOR) following unilateral vestibular loss were characterized by dynamic reweighting of inputs from vestibular and extravestibular modalities at the level of single neurons that constitute the first central stage of VOR signal processing. Here, we studied another class of neurons, i.e., the vestibular-only neurons, in the vestibular nuclei that mediate vestibulospinal reflexes and provide information for higher brain areas. We investigated changes in the relative contribution of vestibular, neck proprioceptive, and efference copy signals in the response of these neurons during compensation after contralateral vestibular loss in Macaca mulata monkeys. We show that the time course of recovery of vestibular sensitivity of neurons corresponds with that of lower extremity muscle and tendon reflexes reported in previous studies. More important, we found that information from neck proprioceptors, which did not influence neuronal responses before the lesion, were unmasked after lesion. Such inputs influenced the early stages of the compensation process evidenced by faster and more substantial recovery of the resting discharge in proprioceptive-sensitive neurons. Interestingly, unlike our previous study of VOR interneurons, the improvement in the sensitivity of the two groups of neurons did not show any difference in the early or late stages after lesion. Finally, neuronal responses during active head movements were not different before and after lesion and were attenuated relative to passive movements over the course of recovery, similar to that observed in control conditions. Comparison of compensatory changes observed in the vestibuloocular and vestibulospinal pathways provides evidence for similarities and differences between the two classes of neurons that mediate these pathways at the functional and cellular levels. PMID:21148096

Multimodal integration after unilateral labyrinthine lesion: single vestibular nuclei neuron responses and implications for postural compensation.

PubMed

Sadeghi, Soroush G; Minor, Lloyd B; Cullen, Kathleen E

2011-02-01

Plasticity in neuronal responses is necessary for compensation following brain lesions and adaptation to new conditions and motor learning. In a previous study, we showed that compensatory changes in the vestibuloocular reflex (VOR) following unilateral vestibular loss were characterized by dynamic reweighting of inputs from vestibular and extravestibular modalities at the level of single neurons that constitute the first central stage of VOR signal processing. Here, we studied another class of neurons, i.e., the vestibular-only neurons, in the vestibular nuclei that mediate vestibulospinal reflexes and provide information for higher brain areas. We investigated changes in the relative contribution of vestibular, neck proprioceptive, and efference copy signals in the response of these neurons during compensation after contralateral vestibular loss in Macaca mulata monkeys. We show that the time course of recovery of vestibular sensitivity of neurons corresponds with that of lower extremity muscle and tendon reflexes reported in previous studies. More important, we found that information from neck proprioceptors, which did not influence neuronal responses before the lesion, were unmasked after lesion. Such inputs influenced the early stages of the compensation process evidenced by faster and more substantial recovery of the resting discharge in proprioceptive-sensitive neurons. Interestingly, unlike our previous study of VOR interneurons, the improvement in the sensitivity of the two groups of neurons did not show any difference in the early or late stages after lesion. Finally, neuronal responses during active head movements were not different before and after lesion and were attenuated relative to passive movements over the course of recovery, similar to that observed in control conditions. Comparison of compensatory changes observed in the vestibuloocular and vestibulospinal pathways provides evidence for similarities and differences between the two classes of neurons that mediate these pathways at the functional and cellular levels.

Vestibular evoked myogenic potentials and health-related quality of life in patients with vestibular neuritis.

PubMed

Viciana, David; Lopez-Escamez, Jose A

2010-08-01

To evaluate the usefulness of vestibular evoked myogenic potentials (VEMPs) in subjects with vestibular neuritis (VN) and to determine the impact of the disease in health-related quality of life (HRQoL). Case series. Tertiary referral center. Fifty patients with VN (episode of sudden onset of prolonged vertigo [>24 h] associated with peripheral vestibular hypofunction, imbalance in absence of hearing loss, or other neurologic symptoms). VEMPs were measured in 41 patients by using an air-conducted 500 Hz tone burst. HRQoL was evaluated in all cases by the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) and Dizziness Handicap Inventory Short Form (DHI-S) instruments, after the acute episode was resolved. Latencies P1 or N1 peaks, corrected amplitude or the absence of response, for VEMPs; scores obtained in SF-36 and DHI-S instruments. VEMPs showed abnormal results in 21 (51%) of 41 cases, with an increase in ipsilateral latencies for P1 and N1 peaks being the most common finding. Three patients (7%) had ipsilateral abnormal VEMP response with normal caloric response, indicating isolated involvement of inferior vestibular nerve. The total score obtained for the DHI-S was 14.76 +/- 11.07 (range, 0-34/40), suggesting a variable impact among patients with VN. For the SF-36, scores in men with VN were worse than their age-matched controls for all dimensions, except for mental health. However, women only showed lower scores for general health and social function. Abnormal VEMP responses demonstrate the involvement of the inferior vestibular nerve in half of the patients with VN. Moreover, VN has a moderate impact in HRQoL, and it is perceived more disabling by men than women.

Auditory biofeedback substitutes for loss of sensory information in maintaining stance.

PubMed

Dozza, Marco; Horak, Fay B; Chiari, Lorenzo

2007-03-01

The importance of sensory feedback for postural control in stance is evident from the balance improvements occurring when sensory information from the vestibular, somatosensory, and visual systems is available. However, the extent to which also audio-biofeedback (ABF) information can improve balance has not been determined. It is also unknown why additional artificial sensory feedback is more effective for some subjects than others and in some environmental contexts than others. The aim of this study was to determine the relative effectiveness of an ABF system to reduce postural sway in stance in healthy control subjects and in subjects with bilateral vestibular loss, under conditions of reduced vestibular, visual, and somatosensory inputs. This ABF system used a threshold region and non-linear scaling parameters customized for each individual, to provide subjects with pitch and volume coding of their body sway. ABF had the largest effect on reducing the body sway of the subjects with bilateral vestibular loss when the environment provided limited visual and somatosensory information; it had the smallest effect on reducing the sway of subjects with bilateral vestibular loss, when the environment provided full somatosensory information. The extent that all subjects substituted ABF information for their loss of sensory information was related to the extent that each subject was visually dependent or somatosensory-dependent for their postural control. Comparison of postural sway under a variety of sensory conditions suggests that patients with profound bilateral loss of vestibular function show larger than normal information redundancy among the remaining senses and ABF of trunk sway. The results support the hypothesis that the nervous system uses augmented sensory information differently depending both on the environment and on individual proclivities to rely on vestibular, somatosensory or visual information to control sway.

A short latency vestibular evoked potential (VsEP) produced by bone-conducted acoustic stimulation

NASA Astrophysics Data System (ADS)

McAngus Todd, Neil P.; Rosengren, Sally M.; Colebatch, James G.

2003-12-01

In this paper data are presented from an experiment which provides evidence for the existence of a short latency, acoustically evoked potential of probable vestibular origin. The experiment was conducted in two phases using bone-conducted acoustic stimulation. In the first phase subjects were stimulated with 6-ms, 500-Hz tone bursts in order to obtain the threshold VT for vestibular evoked myogenic potentials (VEMP). It was confirmed that the difference between bone-conducted auditory and acoustic vestibular thresholds was slightly over 30 dB. The estimated threshold was then used as a reference value in the second part of the experiment to stimulate subjects over a range of intensities from -6 to +18 dB (re:VT). Averaged EEG recordings were made with eight Ag/AgCl electrodes placed on the scalp at Fpz, F3, F4, F7, F8, Cz, T3, and T4 according to the 10-20 system. Below VT auditory midlatency responses (MLRs) were observed. Above VT two additional potentials appeared: a positivity at about 10 ms (P10) which was maximal at Cz, and a negativity at about 15 ms (N15) which was maximal at Fpz. Extrapolation of the growth functions for the P10 and N15 indicated a threshold close to VT, consistent with a vestibular origin of these potentials. Given the low threshold of vestibular acoustic sensitivity it is possible that this mode may make a contribution to the detection of and affective responses to loud low frequency sounds. The evoked potentials may also have application as a noninvasive and nontraumatic test of vestibular projections to the cortex.

The Vestibular Effects of Repeated Low-Level Blasts.

PubMed

Littlefield, Philip D; Pinto, Robin L; Burrows, Holly L; Brungart, Douglas S

2016-01-01

The objective of this study was to use a prospective cohort of United States Marine Corps (USMC) instructors to identify any acute or long-term vestibular dysfunction following repeated blast exposures during explosive breaching training. They were assessed in clinic and on location during training at the USMC Methods of Entry School, Quantico, VA. Subjects received comprehensive baseline vestibular assessments and these were repeated in order to identify longitudinal changes. They also received shorter assessments immediately following blast exposure in order to identify acute findings. The main outcome measures were the Neurobehavioral Symptom Inventory, vestibular Visual Analog Scale (VAS) of subjective vestibular function, videonystagmography (VNG), vestibular evoked myogenic potentials (VEMP), rotary chair (including the unilateral centrifugation test), computerized dynamic posturography, and computerized dynamic visual acuity. A total of 11 breachers and 4 engineers were followed for up to 17 months. No acute effects or longitudinal deteriorations were identified, but there were some interesting baseline group differences. Upbeat positional nystagmus was common, and correlated (p<0.005) with a history of mild traumatic brain injury (mTBI). Several instructors had abnormally short low-frequency phase leads on rotary chair testing. This study evaluated breaching instructors over a longer test period than any other study, and the results suggest that this population appears to be safe from a vestibular standpoint at the current exposure levels. Upbeat positional nystagmus correlated with a history of mTBI in this population, and this has not been described elsewhere. The data trends also suggest that this nystagmus could be an acute blast effect. However, the reasons for the abnormally short phase leads seen in rotary chair testing are unclear at this time. Further investigation seems warranted.

Sensitivity and specificity of the amer dizziness diagnostic scale (adds) for patients with vestibular disorders.

PubMed

Al Saif, Amer; Alsenany, Samira

2015-01-01

[Purpose] To investigate the sensitivity and specificity of a newly developed diagnostic tool, the Amer Dizziness Diagnostic Scale (ADDS), to evaluate and differentially diagnose vestibular disorder and to identify the strengths and weaknesses of the scale and its usefulness in clinical practice. [Subjects and Methods] Two hundred subjects of both genders (72 males, 128 females) aged between 18 to 60 (49.5±7.8) who had a history of vertigo and/or dizziness symptoms for this previous two weeks or less were recruited for the study. All subjects were referred by otolaryngologists, neurologists or family physicians in and around Jeddah, Kingdom of Saudi Arabia. On the first clinic visit, all the patients were evaluated once using the ADDS, following which they underwent routine testing of clinical signs and symptoms, audiometry, and a neurological examination, coupled with tests of Vestibulo-Ocular Reflex function, which often serves as the "gold standard" for determining the probability of a vestibular deficit. [Results] The results show that the ADDS strongly correlated with "true-positive" and "true-negative" responses for determining the probability of a vestibular disorder (r =0.95). A stepwise linear regression was conducted and the results indicate that the ADDS was a significant predictor of "true-positive" and "true-negative" responses in vestibular disorders (R(2) =0.90). Approximately 90% of the variability in the vestibular gold standard test was explained by its relationship to the ADDS. Moreover, the ADDS was found to have a sensitivity of 96% and a specificity of 96%. [Conclusion] This study showed that the Amer Dizziness Diagnostic Scale has high sensitivity and specificity and that it can be used as a method of differential diagnosis for patients with vestibular disorders.

The nucleus of the optic tract. Its function in gaze stabilization and control of visual-vestibular interaction

NASA Technical Reports Server (NTRS)

Cohen, B.; Reisine, H.; Yokota, J. I.; Raphan, T.

1992-01-01

1. Electrical stimulation of the nucleus of the optic tract (NOT) induced nystagmus and after-nystagmus with ipsilateral slow phases. The velocity characteristics of the nystagmus were similar to those of the slow component of optokinetic nystagmus (OKN) and to optokinetic after-nystagmus (OKAN), both of which are produced by velocity storage in the vestibular system. When NOT was destroyed, these components disappeared. This indicates that velocity storage is activated from the visual system through NOT. 2. Velocity storage produces compensatory eye-in-head and head-on-body movements through the vestibular system. The association of NOT with velocity storage implies that NOT helps stabilize gaze in space during both passive motion and active locomotion in light with an angular component. It has been suggested that "vestibular-only" neurons in the vestibular nuclei play an important role in generation of velocity storage. Similarities between the rise and fall times of eye velocity during OKN and OKAN to firing rates of vestibular-only neurons suggest that these cells may receive their visual input through NOT. 3. One NOT was injected with muscimol, a GABAA agonist. Ipsilateral OKN and OKAN were lost, suggesting that GABA, which is an inhibitory transmitter in NOT, acts on projection pathways to the brain stem. A striking finding was that visual suppression and habituation of contralateral slow phases of vestibular nystagmus were also abolished after muscimol injection. The latter implies that NOT plays an important role in producing visual suppression of the VOR and habituating its time constant. 4. Habituation is lost after nodulus and uvula lesions and visual suppression after lesions of the flocculus and paraflocculus. We postulate that the disappearance of vestibular habituation and of visual suppression of vestibular responses after muscimol injections was due to dysfacilitation of the prominent NOT-inferior olive pathway, inactivating climbing fibers from the dorsal cap to nodulouvular and flocculoparafloccular Purkinje cells. The prompt loss of habituation when NOT was inactivated, and its return when the GABAergic inhibition dissipated, suggests that although VOR habituation can be relatively permanent, it must be maintained continuously by activity of the vestibulocerebellum.

The genetics of hair-cell function in zebrafish.

PubMed

Nicolson, Teresa

2017-09-01

Our ears are remarkable sensory organs, providing the important senses of balance and hearing. The complex structure of the inner ear, or 'labyrinth', along with the assorted neuroepithelia, have evolved to detect head movements and sounds with impressive sensitivity. The rub is that the inner ear is highly vulnerable to genetic lesions and environmental insults. According to National Institute of Health estimates, hearing loss is one of the most commonly inherited or acquired sensorineural diseases. To understand the causes of deafness and balance disorders, it is imperative to understand the underlying biology of the inner ear, especially the inner workings of the sensory receptors. These receptors, which are termed hair cells, are particularly susceptible to genetic mutations - more than two dozen genes are associated with defects in this cell type in humans. Over the past decade, a substantial amount of progress has been made in working out the molecular basis of hair-cell function using vertebrate animal models. Given the transparency of the inner ear and the genetic tools that are available, zebrafish have become an increasingly popular animal model for the study of deafness and vestibular dysfunction. Mutagenesis screens for larval defects in hearing and balance have been fruitful in finding key components, many of which have been implicated in human deafness. This review will focus on the genes that are required for hair-cell function in zebrafish, with a particular emphasis on mechanotransduction. In addition, the generation of new tools available for the characterization of zebrafish hair-cell mutants will be discussed.

Cross-Modal Attention Effects in the Vestibular Cortex during Attentive Tracking of Moving Objects.

PubMed

Frank, Sebastian M; Sun, Liwei; Forster, Lisa; Tse, Peter U; Greenlee, Mark W

2016-12-14

The midposterior fundus of the Sylvian fissure in the human brain is central to the cortical processing of vestibular cues. At least two vestibular areas are located at this site: the parietoinsular vestibular cortex (PIVC) and the posterior insular cortex (PIC). It is now well established that activity in sensory systems is subject to cross-modal attention effects. Attending to a stimulus in one sensory modality enhances activity in the corresponding cortical sensory system, but simultaneously suppresses activity in other sensory systems. Here, we wanted to probe whether such cross-modal attention effects also target the vestibular system. To this end, we used a visual multiple-object tracking task. By parametrically varying the number of tracked targets, we could measure the effect of attentional load on the PIVC and the PIC while holding the perceptual load constant. Participants performed the tracking task during functional magnetic resonance imaging. Results show that, compared with passive viewing of object motion, activity during object tracking was suppressed in the PIVC and enhanced in the PIC. Greater attentional load, induced by increasing the number of tracked targets, was associated with a corresponding increase in the suppression of activity in the PIVC. Activity in the anterior part of the PIC decreased with increasing load, whereas load effects were absent in the posterior PIC. Results of a control experiment show that attention-induced suppression in the PIVC is stronger than any suppression evoked by the visual stimulus per se. Overall, our results suggest that attention has a cross-modal modulatory effect on the vestibular cortex during visual object tracking. In this study we investigate cross-modal attention effects in the human vestibular cortex. We applied the visual multiple-object tracking task because it is known to evoke attentional load effects on neural activity in visual motion-processing and attention-processing areas. Here we demonstrate a load-dependent effect of attention on the activation in the vestibular cortex, despite constant visual motion stimulation. We find that activity in the parietoinsular vestibular cortex is more strongly suppressed the greater the attentional load on the visual tracking task. These findings suggest cross-modal attentional modulation in the vestibular cortex. Copyright © 2016 the authors 0270-6474/16/3612720-09$15.00/0.

The impact of cardiovascular drugs on the efficacy of local anesthesia in dentistry.

PubMed

Milosavljevic, Мarko J; Jankovic, Slobodan M

2016-12-01

Drugs used chronically by patients with diseases of the cardiovascular system (group C of the ATC classification) may act on adrenergic receptors and/or certain ion channels, which gives them the potential to interact with the action of local dental anesthetics. The aim of the study was to investigate the effect of systemically administered chronic cardiovascular medication (oral route) on the efficacy of intraoral local anesthesia in patients with diseases of the cardiovascular system. This was a prospective cohort study which analyzed the efficacy of local terminal anesthesia (onset of anesthesia, duration anesthetized area) in the upper jaw of 70 patients: 40 patients on medication for cardiovascular system disorders and 30 patients who were not using these drugs (the control group). The following cardiovascular drugs were used: beta blockers, angiotensin converting enzyme inhibitors, calcium channel blockers, vasodilatators, diuretics, angiotensin receptor blockers, antiarrhythmics, statins and alfa blockers. The onset of anesthesia on the vestibular side was faster in those taking cardiovascular drugs (40.50±19.87 s) than the control patients (58.93±31.07 s; P = 0.004) and duration of anesthesia on this side was shorter. Although the difference was not significant, it was evident that on vestibular and palatal side the anesthetized area was more rapidly reduced in the patients taking cardiovascular drugs. The duration of cardiovascular therapy also had a significant impact on the anesthetized area. Drugs acting on cardiovascular system may influence the effect of local anesthetics used in dentistry, possibly through interaction with autonomic receptors and ion channels.

Vestibulo-cortical Hemispheric Dominance: the link between Anxiety and the Vestibular System?

PubMed

Bednarczuk, Nadja F; Casanovas Ortega, Marta; Fluri, Anne-Sophie; Arshad, Qadeer

2018-05-16

Vestibular processing and anxiety networks are functionally intertwined, as demonstrated by reports of reciprocal influences upon each other. Yet whether there is an underlying link between these two systems remains unknown Previous findings have highlighted the involvement of hemispheric lateralisation in processing of both anxiety and vestibular signals. Accordingly, we explored the interaction between vestibular cortical processing and anxiety by assessing the relationship between anxiety levels and the degree of hemispheric lateralisation of vestibulo-cortical processing in 64 right-handed, healthy individuals. Vestibulo-cortical hemispheric lateralisation was determined by gaging the degree of caloric-induced nystagmus suppression following modulation of cortical excitability using trans-cranial direct current stimulation targeted over the posterior parietal cortex, an area implicated in the processing of vestibular signals. The degree of nystagmus suppression yields an objective biomarker, allowing the quantification of the degree of right vestibulo-cortical hemisphere dominance. Anxiety levels were quantified using the Trait component of the Spielberger State-Trait Anxiety Questionnaire. Our findings demonstrate that the degree of an individual's vestibulo-cortical hemispheric dominance correlates with their anxiety levels. That is, those individuals with greater right hemispheric vestibulo-cortical dominance exhibited lower levels of anxiety. By extension, our results support the notion that hemispheric lateralisation determines an individual's emotional processing, thereby linking cortical circuits involved in processing anxiety and vestibular signals respectively. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Sensory convergence in the parieto-insular vestibular cortex

PubMed Central

Shinder, Michael E.

2014-01-01

Vestibular signals are pervasive throughout the central nervous system, including the cortex, where they likely play different roles than they do in the better studied brainstem. Little is known about the parieto-insular vestibular cortex (PIVC), an area of the cortex with prominent vestibular inputs. Neural activity was recorded in the PIVC of rhesus macaques during combinations of head, body, and visual target rotations. Activity of many PIVC neurons was correlated with the motion of the head in space (vestibular), the twist of the neck (proprioceptive), and the motion of a visual target, but was not associated with eye movement. PIVC neurons responded most commonly to more than one stimulus, and responses to combined movements could often be approximated by a combination of the individual sensitivities to head, neck, and target motion. The pattern of visual, vestibular, and somatic sensitivities on PIVC neurons displayed a continuous range, with some cells strongly responding to one or two of the stimulus modalities while other cells responded to any type of motion equivalently. The PIVC contains multisensory convergence of self-motion cues with external visual object motion information, such that neurons do not represent a specific transformation of any one sensory input. Instead, the PIVC neuron population may define the movement of head, body, and external visual objects in space and relative to one another. This comparison of self and external movement is consistent with insular cortex functions related to monitoring and explains many disparate findings of previous studies. PMID:24671533

Otoliths - Accelerometer and seismometer; Implications in Vestibular Evoked Myogenic Potential (VEMP).

PubMed

Grant, Wally; Curthoys, Ian

2017-09-01

Vestibular otolithic organs are recognized as transducers of head acceleration and they function as such up to their corner frequency or undamped natural frequency. It is well recognized that these organs respond to frequencies above their corner frequency up to the 2-3 kHz range (Curthoys et al., 2016). A mechanics model for the transduction of these organs is developed that predicts the response below the undamped natural frequency as an accelerometer and above that frequency as a seismometer. The model is converted to a transfer function using hair cell bundle deflection. Measured threshold acceleration stimuli are used along with threshold deflections for threshold transfer function values. These are compared to model predicted values, both below and above their undamped natural frequency. Threshold deflection values are adjusted to match the model transfer function. The resulting threshold deflection values were well within in measure threshold bundle deflection ranges. Vestibular Evoked Myogenic Potentials (VEMPs) today routinely uses stimulus frequencies of 500 and 1000 Hz, and otoliths have been established incontrovertibly by clinical and neural evidence as the stimulus source. The mechanism for stimulus at these frequencies above the undamped natural frequency of otoliths is presented where otoliths are utilizing a seismometer mode of response for VEMP transduction. Copyright © 2017 Elsevier B.V. All rights reserved.

Dizziness and vertigo syndromes viewed with a historical eye.

PubMed

Huppert, Doreen; Brandt, Thomas

2018-03-12

Seasickness, fear of heights, and adverse effects of alcohol were the major areas where descriptions of vertigo and dizziness were found in Roman, Greek, and Chinese texts from about 730 BC-600 AD. A few detailed accounts were suggestive of specific vestibular disorders such as Menière's attacks (Huangdi Neijing, the Yellow Thearch's Classic of Internal Medicine) or vestibular migraine (Aretaeus of Cappadocia). Further, the etymological and metaphorical meanings of the terms and their symptoms provide fascinating historical insights, e.g. Vespasian's feelings of dizzy exultations when becoming Emperor (69 AD) after Nero's suicide or the figurative meaning of German "Schwindel" (vertigo) derived from English "swindle" to express "financial fraud" in the Eighteenth century. The growth of knowledge of the vestibular system and its functions began primarily in the Nineteenth century. Erasmus Darwin, however, was ahead of his times. His work Zoonomia, or The Laws of Organic Life in 1794 described new dizziness syndromes and concepts of sensorimotor control including the mechanism of fear of heights as well as made early observations on positional alcohol vertigo. The latter is beautifully illustrated by the German poet and cartoonist Wilhelm Busch (1832-1908) who also documented the alleviating effect of the "morning after drink". The mechanism underlying positional alcohol vertigo, i.e., the differential gravities of alcohol and endolymph, was discovered later in the Nineteenth century. The first textbook on neurology (Lehrbuch der Nervenkrankheiten des Menschen, 1840) by Moritz Romberg contained general descriptions of signs and symptoms of various conditions having the key symptom of vertigo, but no definition of vestibular disorders. Our current knowledge of vestibular function and disorders dates back to the seminal work of a group of Nineteenth century scientists, e.g., Jan Evangelista Purkinje, Ernst Mach, Josef Breuer, Hermann Helmholtz, and Alexander Crum-Brown.

Place of Gamma Knife Stereotactic Radiosurgery in Grade 4 Vestibular Schwannoma Based on Case Series of 86 Patients with Long-Term Follow-Up.

PubMed

Lefranc, Michel; Da Roz, Leila Maria; Balossier, Anne; Thomassin, Jean Marc; Roche, Pierre Hugue; Regis, Jean

2018-06-01

Grade IV vestibular schwannoma (Koos classification) is generally considered to be an indication for microsurgical resection or combined radiosurgery-microsurgery. However, the place of Gamma Knife stereotactic surgery (GK-SRS), either as first-line treatment or when progression of residual tumor compresses the brainstem, has not been clearly evaluated. This article reports the results of a large case series of patients with grade 4 vestibular schwannoma treated by GK-SRS. All consecutive patients with grade IV vestibular schwannoma treated by GK-SRS in our department between 1996 and 2011 with a minimum follow-up of 3 years were included in this study. 86 patients were treated by GK-SRS with a minimum follow-up of 3 years. Mean follow-up was 6.2 years (3-16 years). The mean age of the patients at the time of GK-SRS was 54.6 years (range: 23-84) and the sex ratio was 0.6. At the time of radiosurgery, no patient presented brainstem dysfunction prior to GK-SRS. 38 patients had functional hearing before treatment. One patient presented mild trigeminal neuralgia before GK-SRS. Tumor control with no clinical deterioration was obtained in 78 patients (90.7%). No radiation-induced brainstem or cranial nerve toxicity was observed in any of these patients. Functional hearing was maintained in 25 patients. 8 (9.3%) patients presented tumor growth and required microsurgical resection in 7 cases and ventricular shunt in 1 case. On the basis of this large series, GK-SRS appears to be a safe and effective treatment option for grade IV vestibular schwannoma for patients with no signs of brainstem dysfunction. Copyright © 2018 Elsevier Inc. All rights reserved.

Effect of Developmental Binocular Vision Abnormalities on Visual Vertigo Symptoms and Treatment Outcome.

PubMed

Pavlou, Marousa; Acheson, James; Nicolaou, Despina; Fraser, Clare L; Bronstein, Adolfo M; Davies, Rosalyn A

2015-10-01

Customized vestibular rehabilitation incorporating optokinetic (OK) stimulation improves visual vertigo (VV) symptoms; however, the degree of improvement varies among individuals. Binocular vision abnormalities (misalignment of ocular axis, ie, strabismus) may be a potential risk factor. This study aimed to investigate the influence of binocular vision abnormalities on VV symptoms and treatment outcome. Sixty subjects with refractory peripheral vestibular symptoms underwent an orthoptic assessment after being recruited for participation in an 8-week customized program incorporating OK training via a full-field visual environment rotator or video display, supervised or unsupervised. Treatment response was assessed at baseline and at 8 weeks with dynamic posturography, Functional Gait Assessment (FGA), and questionnaires for symptoms, symptom triggers, and psychological state. As no significant effect of OK training type was noted for any variables, data were combined and new groups identified on the basis of the absence or presence of a binocular vision abnormality. A total of 34 among 60 subjects consented to the orthoptic assessment, of whom 8 of the 34 had binocular vision abnormalities and 30 of the 34 subjects completed both the binocular function assessment and vestibular rehabilitation program. No significant between-group differences were noted at baseline. The only significant between-group difference was observed for pre-/post-VV symptom change (P = 0.01), with significant improvements noted only for the group without binocular vision abnormalities (P < 0.0005). Common vestibular symptoms, posturography, and the FGA improved significantly for both groups (P < 0.05). Binocular vision abnormalities may affect VV symptom improvement. These findings may have important implications for the management of subjects with refractory vestibular symptoms.Video Abstract available for insights from the authors regarding clinical implication of the study findings (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A115).

The functional significance of velocity storage and its dependence on gravity.

PubMed

Laurens, Jean; Angelaki, Dora E

2011-05-01

Research in the vestibular field has revealed the existence of a central process, called 'velocity storage', that is activated by both visual and vestibular rotation cues and is modified by gravity, but whose functional relevance during natural motion has often been questioned. In this review, we explore spatial orientation in the context of a Bayesian model of vestibular information processing. In this framework, deficiencies/ambiguities in the peripheral vestibular sensors are compensated for by central processing to more accurately estimate rotation velocity, orientation relative to gravity, and inertial motion. First, an inverse model of semicircular canal dynamics is used to reconstruct rotation velocity by integrating canal signals over time. However, its low-frequency bandwidth is limited to avoid accumulation of noise in the integrator. A second internal model uses this reconstructed rotation velocity to compute an internal estimate of tilt and inertial acceleration. The bandwidth of this second internal model is also restricted at low frequencies to avoid noise accumulation and drift of the tilt/translation estimator over time. As a result, low-frequency translation can be erroneously misinterpreted as tilt. The time constants of these two integrators (internal models) can be conceptualized as two Bayesian priors of zero rotation velocity and zero linear acceleration, respectively. The model replicates empirical observations like 'velocity storage' and 'frequency segregation' and explains spatial orientation (e.g., 'somatogravic') illusions. Importantly, the functional significance of this network, including velocity storage, is found during short-lasting, natural head movements, rather than at low frequencies with which it has been traditionally studied.

Vestibular Evoked Myogenic Potential (VEMP) Triggered by Galvanic Vestibular Stimulation (GVS): A Promising Tool to Assess Spinal Cord Function in Schistosomal Myeloradiculopathy

PubMed Central

Labanca, Ludimila; Dornas de Oliveira, Leonardo; Vaz de Melo Trindade, Guilherme; de Almeida Pereira, Thiago; Diniz Cunha, Pedro Henrique; Santos Falci Mourão, Marina; Lambertucci, José Roberto

2016-01-01

Background Schistosomal myeloradiculopathy (SMR), the most severe and disabling ectopic form of Schistosoma mansoni infection, is caused by embolized ova eliciting local inflammation in the spinal cord and nerve roots. The treatment involves the use of praziquantel and long-term corticotherapy. The assessment of therapeutic response relies on neurological examination. Supplementary electrophysiological exams may improve prediction and monitoring of functional outcome. Vestibular evoked myogenic potential (VEMP) triggered by galvanic vestibular stimulation (GVS) is a simple, safe, low-cost and noninvasive electrophysiological technique that has been used to test the vestibulospinal tract in motor myelopathies. This paper reports the results of VEMP with GVS in patients with SMR. Methods A cross-sectional comparative study enrolled 22 patients with definite SMR and 22 healthy controls that were submitted to clinical, neurological examination and GVS. Galvanic stimulus was applied in the mastoid bones in a transcranial configuration for testing VEMP, which was recorded by electromyography (EMG) in the gastrocnemii muscles. The VEMP variables of interest were blindly measured by two independent examiners. They were the short-latency (SL) and the medium-latency (ML) components of the biphasic EMG wave. Results VEMP showed the components SL (p = 0.001) and ML (p<0.001) delayed in SMR compared to controls. The delay of SL (p = 0.010) and of ML (p = 0.020) was associated with gait dysfunction. Conclusion VEMP triggered by GVS identified alterations in patients with SMR and provided additional functional information that justifies its use as a supplementary test in motor myelopathies. PMID:27128806

Vestibular Evoked Myogenic Potential (VEMP) Triggered by Galvanic Vestibular Stimulation (GVS): A Promising Tool to Assess Spinal Cord Function in Schistosomal Myeloradiculopathy.

PubMed

Caporali, Júlia Fonseca de Morais; Utsch Gonçalves, Denise; Labanca, Ludimila; Dornas de Oliveira, Leonardo; Vaz de Melo Trindade, Guilherme; de Almeida Pereira, Thiago; Diniz Cunha, Pedro Henrique; Santos Falci Mourão, Marina; Lambertucci, José Roberto

2016-04-01

Schistosomal myeloradiculopathy (SMR), the most severe and disabling ectopic form of Schistosoma mansoni infection, is caused by embolized ova eliciting local inflammation in the spinal cord and nerve roots. The treatment involves the use of praziquantel and long-term corticotherapy. The assessment of therapeutic response relies on neurological examination. Supplementary electrophysiological exams may improve prediction and monitoring of functional outcome. Vestibular evoked myogenic potential (VEMP) triggered by galvanic vestibular stimulation (GVS) is a simple, safe, low-cost and noninvasive electrophysiological technique that has been used to test the vestibulospinal tract in motor myelopathies. This paper reports the results of VEMP with GVS in patients with SMR. A cross-sectional comparative study enrolled 22 patients with definite SMR and 22 healthy controls that were submitted to clinical, neurological examination and GVS. Galvanic stimulus was applied in the mastoid bones in a transcranial configuration for testing VEMP, which was recorded by electromyography (EMG) in the gastrocnemii muscles. The VEMP variables of interest were blindly measured by two independent examiners. They were the short-latency (SL) and the medium-latency (ML) components of the biphasic EMG wave. VEMP showed the components SL (p = 0.001) and ML (p<0.001) delayed in SMR compared to controls. The delay of SL (p = 0.010) and of ML (p = 0.020) was associated with gait dysfunction. VEMP triggered by GVS identified alterations in patients with SMR and provided additional functional information that justifies its use as a supplementary test in motor myelopathies.

The functional significance of velocity storage and its dependence on gravity

PubMed Central

Laurens, Jean

2013-01-01

Research in the vestibular field has revealed the existence of a central process, called ‘velocity storage’, that is activated by both visual and vestibular rotation cues and is modified by gravity, but whose functional relevance during natural motion has often been questioned. In this review, we explore spatial orientation in the context of a Bayesian model of vestibular information processing. In this framework, deficiencies/ambiguities in the peripheral vestibular sensors are compensated for by central processing to more accurately estimate rotation velocity, orientation relative to gravity, and inertial motion. First, an inverse model of semicircular canal dynamics is used to reconstruct rotation velocity by integrating canal signals over time. However, its low-frequency bandwidth is limited to avoid accumulation of noise in the integrator. A second internal model uses this reconstructed rotation velocity to compute an internal estimate of tilt and inertial acceleration. The bandwidth of this second internal model is also restricted at low frequencies to avoid noise accumulation and drift of the tilt/translation estimator over time. As a result, low-frequency translation can be erroneously misinterpreted as tilt. The time constants of these two integrators (internal models) can be conceptualized as two Bayesian priors of zero rotation velocity and zero linear acceleration, respectively. The model replicates empirical observations like ‘velocity storage’ and ‘frequency segregation’ and explains spatial orientation (e.g., ‘somatogravic’) illusions. Importantly, the functional significance of this network, including velocity storage, is found during short-lasting, natural head movements, rather than at low frequencies with which it has been traditionally studied. PMID:21293850

PI-in-a-box: Intelligent onboard assistance for spaceborne experiments in vestibular physiology

NASA Technical Reports Server (NTRS)

Colombano, Silvano; Young, Laurence; Wogrin, Nancy; Rosenthal, Don

1988-01-01

In construction is a knowledge-based system that will aid astronauts in the performance of vestibular experiments in two ways: it will provide real-time monitoring and control of signals and it will optimize the quality of the data obtained, by helping the mission specialists and payload specialists make decisions that are normally the province of a principal investigator, hence the name PI-in-a-box. An important and desirable side-effect of this tool will be to make the astronauts more productive and better integrated members of the scientific team. The vestibular experiments are planned by Prof. Larry Young of MIT, whose team has already performed similar experiments in Spacelab missions SL-1 and D-1, and has experiments planned for SLS-1 and SLS-2. The knowledge-based system development work, performed in collaboration with MIT, Stanford University, and the NASA-Ames Research Center, addresses six major related functions: (1) signal quality monitoring; (2) fault diagnosis; (3) signal analysis; (4) interesting-case detection; (5) experiment replanning; and (6) integration of all of these functions within a real-time data acquisition environment. Initial prototyping work has been done in functions (1) through (4).

Comparison of virtual reality based therapy with customized vestibular physical therapy for the treatment of vestibular disorders.

PubMed

Alahmari, Khalid A; Sparto, Patrick J; Marchetti, Gregory F; Redfern, Mark S; Furman, Joseph M; Whitney, Susan L

2014-03-01

We examined outcomes in persons with vestibular disorders after receiving virtual reality based therapy (VRBT) or customized vestibular physical therapy (PT) as an intervention for habituation of dizziness symptoms. Twenty subjects with vestibular disorders received VRBT and 18 received PT. During the VRBT intervention, subjects walked on a treadmill within an immersive virtual grocery store environment, for six sessions approximately one week apart. The PT intervention consisted of gaze stabilization, standing balance and walking exercises individually tailored to each subject. Before, one week after, and at six months after the intervention, subjects completed self-report and balance performance measures. Before and after each VRBT session, subjects also reported symptoms of nausea, headache, dizziness, and visual blurring. In both groups, significant improvements were noted on the majority of self-report and performance measures one week after the intervention. Subjects maintained improvements on self report and performance measures at six months follow up. There were not between group differences. Nausea, headache, dizziness and visual blurring increased significantly during the VRBT sessions, but overall symptoms were reduced at the end of the six-week intervention. While this study did not find a difference in outcomes between PT and VRBT, the mechanism by which subjects with chronic dizziness demonstrated improvement in dizziness and balance function may be different.

A Multi-channel Semicircular Canal Neural Prosthesis Using Electrical Stimulation to Restore 3D Vestibular Sensation

PubMed Central

Della Santina, Charles C.; Migliaccio, Americo A.; Patel, Amit H.

2009-01-01

Bilateral loss of vestibular sensation can be disabling. Those afflicted suffer illusory visual field movement during head movements, chronic disequilibrium and postural instability due to failure of vestibulo-ocular and vestibulo-spinal reflexes. A neural prosthesis that emulates the normal transduction of head rotation by semicircular canals could significantly improve quality of life for these patients. Like the 3 semicircular canals in a normal ear, such a device should at least transduce 3 orthogonal (or linearly separable) components of head rotation into activity on corresponding ampullary branches of the vestibular nerve. We describe the design, circuit performance and in vivo application of a head-mounted, semi-implantable multi-channel vestibular prosthesis that encodes head movement in 3 dimensions as pulse-frequency-modulated electrical stimulation of 3 or more ampullary nerves. In chinchillas treated with intratympanic gentamicin to ablate vestibular sensation bilaterally, prosthetic stimuli elicited a partly compensatory angular vestibulo-ocular reflex in multiple planes. Minimizing misalignment between the axis of eye and head rotation, apparently caused by current spread beyond each electrode’s targeted nerve branch, emerged as a key challenge. Increasing stimulation selectivity via improvements in electrode design, surgical technique and stimulus protocol will likely be required to restore AVOR function over the full range of normal behavior. PMID:17554821

Head-Shaking Nystagmus Depends on Gravity

PubMed Central

Marti, Sarah; Straumann, Dominik

2005-01-01

In acute unilateral peripheral vestibular deficit, horizontal spontaneous nystagmus (SN) increases when patients lie on their affected ear. This phenomenon indicates an ipsilesional reduction of otolith function that normally suppresses asymmetric semicircular canal signals. We asked whether head-shaking nystagmus (HSN) in patients with chronic unilateral vestibular deficit following vestibular neuritis is influenced by gravity in the same way as SN in acute patients. Using a three-dimensional (3-D) turntable, patients (N = 7) were placed in different whole-body positions along the roll plane and oscillated (1 Hz, ±10°) about their head-fixed vertical axis. Eye movements were recorded with 3-D magnetic search coils. HSN was modulated by gravity: When patients lay on their affected ear, slow-phase eye velocity significantly increased upon head shaking and consisted of a horizontal drift toward the affected ear (average: 1.2°/s ±0.5 SD), which was added to the gravity-independent and directionally nonspecific SN. In conclusion, HSN in patients with chronic unilateral peripheral vestibular deficit is best elicited when they are lying on their affected ear. This suggests a gravity-dependent mechanism similar to the one observed for SN in acute patients, i.e., an asymmetric suppression of vestibular nystagmus by the unilaterally impaired otolith organs. PMID:15735939

Characterization of pulse amplitude and pulse rate modulation for a human vestibular implant during acute electrical stimulation

NASA Astrophysics Data System (ADS)

Nguyen, T. A. K.; DiGiovanna, J.; Cavuscens, S.; Ranieri, M.; Guinand, N.; van de Berg, R.; Carpaneto, J.; Kingma, H.; Guyot, J.-P.; Micera, S.; Perez Fornos, A.

2016-08-01

Objective. The vestibular system provides essential information about balance and spatial orientation via the brain to other sensory and motor systems. Bilateral vestibular loss significantly reduces quality of life, but vestibular implants (VIs) have demonstrated potential to restore lost function. However, optimal electrical stimulation strategies have not yet been identified in patients. In this study, we compared the two most common strategies, pulse amplitude modulation (PAM) and pulse rate modulation (PRM), in patients. Approach. Four subjects with a modified cochlear implant including electrodes targeting the peripheral vestibular nerve branches were tested. Charge-equivalent PAM and PRM were applied after adaptation to baseline stimulation. Vestibulo-ocular reflex eye movement responses were recorded to evaluate stimulation efficacy during acute clinical testing sessions. Main results. PAM evoked larger amplitude eye movement responses than PRM. Eye movement response axes for lateral canal stimulation were marginally better aligned with PRM than with PAM. A neural network model was developed for the tested stimulation strategies to provide insights on possible neural mechanisms. This model suggested that PAM would consistently cause a larger ensemble firing rate of neurons and thus larger responses than PRM. Significance. Due to the larger magnitude of eye movement responses, our findings strongly suggest PAM as the preferred strategy for initial VI modulation.

One-shot, low-dosage intratympanic gentamicin for Ménière's disease: Clinical, posturographic and vestibular test findings.

PubMed

Daneshi, Ahmad; Jahandideh, Hesam; Pousti, Seyed Behzad; Mohammadi, Shabahang

2014-01-01

Ménière's disease has been remained as a difficult therapeutic challenge. The present study aimed to determine the effects of one-shot low-dosage intratympanic gentamicin on vertigo control, auditory outcomes and findings of computerized dynamic posturography and vestibular evoked myogenic potentials in patients with unilateral Ménière's disease. In a prospective clinical study, 30 patients with unilateral Ménière's disease were treated with one-shot intratympanic injection of 20 milligrams gentamicin. Main outcome measures included clinical, audiometric, postural and vestibular outcomes evaluated 1 and 9 months after the treatment. Mean vertigo attacks frequency, pure tone average threshold and functional level scale significantly decreased after the treatment (P < 0.05). Effective vertigo control (class A and B) obtained in 95.8% of the patients. In total, 75% of patients reported decrease in both aural fullness and tinnitus. Vestibular evoked myogenic potentials became absent in all the patients but four of them. Posturographic scores were improved after the treatment. One-shot low-dosage gentamicin was effective in controlling vertigo attacks in Ménière's disease and has useful effects on aural fullness and tinnitus of patients as well. Postural and vestibular tests only have adjunctive role for monitoring therapeutic responses in intratympanic gentamicin-therapy.

Intracellular distributions and putative functions of calcium-binding proteins in the bullfrog vestibular otolith organs

NASA Technical Reports Server (NTRS)

Baird, R. A.; Steyger, P. S.; Schuff, N. R.

1997-01-01

Hair cells in the bullfrog vestibular otolith organs were immunolabeled by monoclonal and polyclonal antisera against calbindin (CaB), calmodulin (CaM), calretinin (CaR), and parvalbumin (PA). S-100, previously shown to immunolabel striolar hair cells in fish vestibular organs, only weakly immunolabeled hair cells in the bullfrog vestibular otolith organs. Immunolabeling was not detected in supporting cells. With the exception of CaR, myelinated axons and unmyelinated nerve terminals were immunolabeled by all of the above antisera. Immunolabeling was seen in all saccular hair cells, although hair cells at the macular margins were immunolabeled more intensely for CaB, CaM, and PA than more centrally located hair cells. As the macula margins are known to be a growth zone, this labeling pattern suggests that marginal hair cells up-regulate their calcium-binding proteins during hair cell development. In the utriculus, immunolabeling for CaM and PA was generally restricted to striolar hair cells. CaR immunolabeling was restricted to the stereociliary array. Immunolabeling for other calcium-binding proteins was generally seen in both the cell body and hair bundles of hair cells, although this labeling was often localized to the stereociliary array and the apical portion of the cell body. CaM and PA immunolabeling in the stereociliary array in saccular and utricular striolar cells suggests a functional role for these proteins in mechanoelectric transduction and adaptation.

Gravity and the cells of gravity receptors in mammals

NASA Technical Reports Server (NTRS)

Ross, M. D.

1983-01-01

A model of the mammalian gravity receptor system is presented, with attention given to the effects of weightlessness. Two receptors are on each side of the head, with end organs in the saccule and utricle of the vestibular membranous labyrinth of the inner ear, embedded in the temporal bone. Each end organ has a macula, containing hair cells and supporting cells, and an otoconial complex, an otoconial membrane and mineral masses called otoconia. X ray powder diffraction examinations have revealed that the otoconia can behave like crystals, i.e., with piezoelectric properties, due to the mineral deposits. Bending of the hair cells because of acceleration can put pressure on the otoconial mineral, producing an electrical signal in the absence of a gravitational field. The possibility that pyroelectricity, as well as piezoelectricity, is present in the otoconial complexes, is discussed.

[The importance of vestibular evoked myogenic potentials for the assessment of the otolith function in the patients presenting with benign paroxysmal positional vertigo].

PubMed

Kunel'skaya, N L; Baybakova, E V; Guseva, A L; Chugunova, M A; Manaenkova, E A

The objective of the present study was to evaluate the otolith function in the patients presenting with idiopathic benign paroxysmal positional vertigo (pBPPV) attributable to the occlusion of the posterior semicircular canal (PSCC) of the inner ear with the use of vestibular evoked myogenic potentials (VEMP). Cervical (cVEMP) and ocular VEMP (oVEMP) were measured in 34 patients with idiopathic pBPPV before and 7 days after the treatment by means of reposition maneuvers. The results of the repeated Dix-Hallpike test performed 7 days after the repositioning maneuver were negative in 27 patients and positive in 7 patients. There was no statistically significant difference in the amplitude of cervical VEMP between the healthy and affected ears either before or after the repositioning treatment. The measurement of oVEMP revealed a reduction of the response amplitude on the affected side. The average values of the plnl on the healthy side were 12.84±1.09 and those on the affected side 4.62±0.69 (p<0,05). The successful repositioning treatment resulted in a significant increase of the oVEMP amplitude on the affected side (p<0,05). In the patients presenting with the persistent symptoms of pBPPV, the repositioning maneuvers did not cause an appreciable increase in the amplitude of oVEMP on the affected side (p<0.05). The results of the present study give evidence that pBPPV of the posterior semicircular canal is associated with the impairment of the function of the receptor structures of the utriculus and the preserved function of the succulus as suggested by the reduction of the oVEMP amplitude and clinically significant asymmetry of ocular VEMP on the affected side with intact cervical VEMP on both sides. The successful treatment of pBPPV of PSCC with the use of the liberatory maneuver results in the increase of the oVEMP amplitude on the affected side increases while the response asymmetry between both sides significantly decreases which indicates the repair of the utriculus otolith function.

Amiodarone-associated bilateral vestibulopathy.

PubMed

Gürkov, Robert; Manzari, Leonardo; Blödow, Alexander; Wenzel, Angela; Pavlovic, Dusan; Luis, Leonal

2018-03-01

Bilateral vestibulopathy (BVP) is a debilitating disorder characterized by the hypofunction of both vestibular end organs or nerves. The most frequent identifiable causes of BVP are ototoxic drug effects, infectious and autoimmune disorders. The majority of cases, however, remain idiopathic. Medical records of patients diagnosed with idiopathic BVP were examined in five dizziness clinics. We identified 126 patients with "idiopathic" BVP. Out of these, 15 patients had a history of Amiodarone treatment before the diagnosis of BVP, resulting in a 12% prevalence. The present report supports the hypothesis that Amiodarone can cause BVP. Vestibular examination in patients taking Amiodarone and suffering from balance-related symptoms are recommended, to recognize this adverse effect as early as possible and allow for an informed judgement on a potential dose reduction or withdrawal for recovery of the vestibular function.

A reevaluation of the vestibulo-ocular reflex: new ideas of its purpose, properties, neural substrate, and disorders

NASA Technical Reports Server (NTRS)

Leigh, R. J.; Brandt, T.

1993-01-01

Conventional views of the vestibulo-ocular reflex (VOR) have emphasized testing with caloric stimuli and by passively rotating patients at low frequencies in a chair. The properties of the VOR tested under these conditions differ from the performance of this reflex during the natural function for which it evolved--locomotion. Only the VOR (and not visually mediated eye movements) can cope with the high-frequency angular and linear perturbations of the head that occur during locomotion; this is achieved by generating eye movements at short latency (< 16 msec). Interpretation of vestibular testing is enhanced by the realization that, although the di- and trisynaptic components of the VOR are essential for this short-latency response, the overall accuracy and plasticity of the VOR depend upon a distributed, parallel network of neurons involving the vestibular nuclei. Neurons in this network variously upon a distributed, parallel network of neurons involving the vestibular nuclei. Neurons in this network variously encode inputs from the labyrinthine semicircular canals and otoliths, as well as from the visual and somatosensory systems. The central vestibular pathways branch to contact vestibular cortex (for perception) and the spinal cord (for control of posture). Thus, the vestibular nuclei basically coordinate the stabilization of gaze and posture, and contribute to the perception of verticality and self-motion. Consequently, brainstem disorders that disrupt the VOR cause not just only nystagmus, but also instability of posture (eg, increased fore-aft sway in patients with downbeat nystagmus) and disturbance of spatial orientation (eg, tilt of the subjective visual vertical in Wallenberg's syndrome).

Interactive wiimote gaze stabilization exercise training system for patients with vestibular hypofunction

PubMed Central

2012-01-01

Background Peripheral vestibular hypofunction is a major cause of dizziness. When complicated with postural imbalance, this condition can lead to an increased incidence of falls. In traditional clinical practice, gaze stabilization exercise is commonly used to rehabilitate patients. In this study, we established a computer-aided vestibular rehabilitation system by coupling infrared LEDs to an infrared receiver. This system enabled the subjects’ head-turning actions to be quantified, and the training was performed using vestibular exercise combined with computer games and interactive video games that simulate daily life activities. Methods Three unilateral and one bilateral vestibular hypofunction patients volunteered to participate in this study. The participants received 30 minutes of computer-aided vestibular rehabilitation training 2 days per week for 6 weeks. Pre-training and post-training assessments were completed, and a follow-up assessment was completed 1 month after the end of the training period. Results After 6 weeks of training, significant improvements in balance and dynamic visual acuity (DVA) were observed in the four participants. Self-reports of dizziness, anxiety and depressed mood all decreased significantly. Significant improvements in self-confidence and physical performance were also observed. The effectiveness of this training was maintained for at least 1 month after the end of the training period. Conclusion Real-time monitoring of training performance can be achieved using this rehabilitation platform. Patients demonstrated a reduction in dizziness symptoms after 6 weeks of training with this short-term interactive game approach. This treatment paradigm also improved the patients’ balance function. This system could provide a convenient, safe and affordable treatment option for clinical practitioners. PMID:23043886

Video Head Impulse Test to Preoperatively Identify the Nerve of Origin of Vestibular Schwannomas.

PubMed

Constanzo, Felipe; Sens, Patricia; Teixeira, Bernardo Corrêa de Almeida; Ramina, Ricardo

2018-05-10

Identification of the nerve of origin in vestibular schwannoma (VS) is an important prognostic factor for hearing preservation surgery. Thus far, vestibular functional tests and magnetic resonance imaging have not yielded reliable results to preoperatively evaluate this information. The development of the video head impulse test (vHIT) has allowed a precise evaluation of each semicircular canal, and its localizing value has been tested for some peripheral vestibular diseases, but not for VS. To correlate patterns of semicircular canal alteration on vHIT to intraoperative identification of the nerve of origin of VSs. A total 31 patients with sporadic VSs were preoperatively evaluated with vHIT (gain of vestibule-ocular reflex, overt and covert saccades on each semicircular canal) and then the nerve of origin was surgically identified during surgical resection via retrosigmoid approach. vHIT results were classified as normal, isolated superior vestibular nerve (SVN) pattern, isolated inferior vestibular nerve (IVN) pattern, predominant SVN pattern, and predominant IVN pattern. Hannover classification, cystic component, and distance between the tumor and the end of the internal auditory canal were also considered for analysis. Three patients had a normal vHIT, 12 had an isolated SVN pattern, 5 had an isolated IVN pattern, 7 had a predominant SVN pattern, and 4 had a predominant IVN pattern. vHIT was able to correctly identify the nerve of origin in 89.7% of cases (100% of altered exams). The pattern of semicircular canal dysfunction on vHIT has a localizing value to identify the nerve of origin in VSs.

Interactive wiimote gaze stabilization exercise training system for patients with vestibular hypofunction.

PubMed

Chen, Po-Yin; Hsieh, Wan-Ling; Wei, Shun-Hwa; Kao, Chung-Lan

2012-10-09

Peripheral vestibular hypofunction is a major cause of dizziness. When complicated with postural imbalance, this condition can lead to an increased incidence of falls. In traditional clinical practice, gaze stabilization exercise is commonly used to rehabilitate patients. In this study, we established a computer-aided vestibular rehabilitation system by coupling infrared LEDs to an infrared receiver. This system enabled the subjects' head-turning actions to be quantified, and the training was performed using vestibular exercise combined with computer games and interactive video games that simulate daily life activities. Three unilateral and one bilateral vestibular hypofunction patients volunteered to participate in this study. The participants received 30 minutes of computer-aided vestibular rehabilitation training 2 days per week for 6 weeks. Pre-training and post-training assessments were completed, and a follow-up assessment was completed 1 month after the end of the training period. After 6 weeks of training, significant improvements in balance and dynamic visual acuity (DVA) were observed in the four participants. Self-reports of dizziness, anxiety and depressed mood all decreased significantly. Significant improvements in self-confidence and physical performance were also observed. The effectiveness of this training was maintained for at least 1 month after the end of the training period. Real-time monitoring of training performance can be achieved using this rehabilitation platform. Patients demonstrated a reduction in dizziness symptoms after 6 weeks of training with this short-term interactive game approach. This treatment paradigm also improved the patients' balance function. This system could provide a convenient, safe and affordable treatment option for clinical practitioners.

Statistics of the Vestibular Input Experienced during Natural Self-Motion: Implications for Neural Processing

PubMed Central

Carriot, Jérome; Jamali, Mohsen; Chacron, Maurice J.

2014-01-01

It is widely believed that sensory systems are optimized for processing stimuli occurring in the natural environment. However, it remains unknown whether this principle applies to the vestibular system, which contributes to essential brain functions ranging from the most automatic reflexes to spatial perception and motor coordination. Here we quantified, for the first time, the statistics of natural vestibular inputs experienced by freely moving human subjects during typical everyday activities. Although previous studies have found that the power spectra of natural signals across sensory modalities decay as a power law (i.e., as 1/fα), we found that this did not apply to natural vestibular stimuli. Instead, power decreased slowly at lower and more rapidly at higher frequencies for all motion dimensions. We further establish that this unique stimulus structure is the result of active motion as well as passive biomechanical filtering occurring before any neural processing. Notably, the transition frequency (i.e., frequency at which power starts to decrease rapidly) was lower when subjects passively experienced sensory stimulation than when they actively controlled stimulation through their own movement. In contrast to signals measured at the head, the spectral content of externally generated (i.e., passive) environmental motion did follow a power law. Specifically, transformations caused by both motor control and biomechanics shape the statistics of natural vestibular stimuli before neural processing. We suggest that the unique structure of natural vestibular stimuli will have important consequences on the neural coding strategies used by this essential sensory system to represent self-motion in everyday life. PMID:24920638

Spatial reference frames of visual, vestibular, and multimodal heading signals in the dorsal subdivision of the medial superior temporal area.

PubMed

Fetsch, Christopher R; Wang, Sentao; Gu, Yong; Deangelis, Gregory C; Angelaki, Dora E

2007-01-17

Heading perception is a complex task that generally requires the integration of visual and vestibular cues. This sensory integration is complicated by the fact that these two modalities encode motion in distinct spatial reference frames (visual, eye-centered; vestibular, head-centered). Visual and vestibular heading signals converge in the primate dorsal subdivision of the medial superior temporal area (MSTd), a region thought to contribute to heading perception, but the reference frames of these signals remain unknown. We measured the heading tuning of MSTd neurons by presenting optic flow (visual condition), inertial motion (vestibular condition), or a congruent combination of both cues (combined condition). Static eye position was varied from trial to trial to determine the reference frame of tuning (eye-centered, head-centered, or intermediate). We found that tuning for optic flow was predominantly eye-centered, whereas tuning for inertial motion was intermediate but closer to head-centered. Reference frames in the two unimodal conditions were rarely matched in single neurons and uncorrelated across the population. Notably, reference frames in the combined condition varied as a function of the relative strength and spatial congruency of visual and vestibular tuning. This represents the first investigation of spatial reference frames in a naturalistic, multimodal condition in which cues may be integrated to improve perceptual performance. Our results compare favorably with the predictions of a recent neural network model that uses a recurrent architecture to perform optimal cue integration, suggesting that the brain could use a similar computational strategy to integrate sensory signals expressed in distinct frames of reference.

Postural threat differentially affects the feedforward and feedback components of the vestibular-evoked balance response.

PubMed

Osler, Callum J; Tersteeg, M C A; Reynolds, Raymond F; Loram, Ian D

2013-10-01

Circumstances may render the consequence of falling quite severe, thus maximising the motivation to control postural sway. This commonly occurs when exposed to height and may result from the interaction of many factors, including fear, arousal, sensory information and perception. Here, we examined human vestibular-evoked balance responses during exposure to a highly threatening postural context. Nine subjects stood with eyes closed on a narrow walkway elevated 3.85 m above ground level. This evoked an altered psycho-physiological state, demonstrated by a twofold increase in skin conductance. Balance responses were then evoked by galvanic vestibular stimulation. The sway response, which comprised a whole-body lean in the direction of the edge of the walkway, was significantly and substantially attenuated after ~800 ms. This demonstrates that a strong reason to modify the balance control strategy was created and subjects were highly motivated to minimise sway. Despite this, the initial response remained unchanged. This suggests little effect on the feedforward settings of the nervous system responsible for coupling pure vestibular input to functional motor output. The much stronger, later effect can be attributed to an integration of balance-relevant sensory feedback once the body was in motion. These results demonstrate that the feedforward and feedback components of a vestibular-evoked balance response are differently affected by postural threat. Although a fear of falling has previously been linked with instability and even falling itself, our findings suggest that this relationship is not attributable to changes in the feedforward vestibular control of balance. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Functional support of glutamate as a vestibular hair cell transmitter in an amniote

NASA Technical Reports Server (NTRS)

Cochran, S. L.; Correia, M. J.

1995-01-01

Although hair cells in the cochlea and in the vestibular endorgans of anamniotes are thought to release glutamate or a similar compound as their transmitter, there is little evidence in amniotes (which, unlike anamniotes, possess both type I and II hair cells) as to the nature of the hair cell transmitters in the vestibular labyrinth. We have recorded extracellularly from single semicircular canal afferents in the turtle labyrinth maintained in vitro and have bath-applied a number of transmitter agonists and antagonists to relate the effects of these substances to the actions of the endogenous transmitter substances. Both glutamate and aspartate strongly excite the afferents while GABA and carbachol have negligible or weak effects. In contrast to its lack of effect on afferent activity in some anamniotes, N-methyl-D-aspartate (NMDA) was also found to excite these afferents. Kynurenic acid reversibly reduced the resting firing rates of the afferents and the increases in firing due to the application of glutamate and aspartate. These findings provide preliminary support for the hypothesis that glutamate (or a related compound) is also a vestibular hair cell transmitter in amniotes.

BMP regulates regional gene expression in the dorsal otocyst through canonical and non-canonical intracellular pathways

PubMed Central

2016-01-01

The inner ear consists of two otocyst-derived, structurally and functionally distinct components: the dorsal vestibular and ventral auditory compartments. BMP signaling is required to form the vestibular compartment, but how it complements other required signaling molecules and acts intracellularly is unknown. Using spatially and temporally controlled delivery of signaling pathway regulators to developing chick otocysts, we show that BMP signaling regulates the expression of Dlx5 and Hmx3, both of which encode transcription factors essential for vestibular formation. However, although BMP regulates Dlx5 through the canonical SMAD pathway, surprisingly, it regulates Hmx3 through a non-canonical pathway involving both an increase in cAMP-dependent protein kinase A activity and the GLI3R to GLI3A ratio. Thus, both canonical and non-canonical BMP signaling establish the precise spatiotemporal expression of Dlx5 and Hmx3 during dorsal vestibular development. The identification of the non-canonical pathway suggests an intersection point between BMP and SHH signaling, which is required for ventral auditory development. PMID:27151948

Vestibular regeneration--experimental models and clinical implications.

PubMed

Albu, Silviu; Muresanu, Dafin F

2012-09-01

Therapies aimed at the protection and/or regeneration of inner ear hair cells are of great interest, given the significant monetary and quality of life impact of balance disorders. Different viral vectors have been shown to transfect various cell types in the inner ear. The past decade has provided tremendous advances in the use of adenoviral vectors to achieve targeted treatment delivery. Several routes of delivery have been identified to introduce vectors into the inner ear while minimizing injury to surrounding structures. Recently, the transcription factor Atoh1 was determined to play a critical role in hair cell differentiation. Adenoviral-mediated overexpression of Atoh1 in culture and in vivo has demonstrated the ability to regenerate vestibular hair cells by causing transdifferentiation of neighbouring epithelial-supporting cells. Functional recovery of the vestibular system has also been documented following adenoviral-induced Atoh1 overexpression. Experiments demonstrating gene transfer in human vestibular epithelial cells reveal that the human inner ear is a suitable target for gene therapy. © 2012 The Authors Journal of Cellular and Molecular Medicine © 2012 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

The Neuroanatomical Correlates of Training-Related Perceptuo-Reflex Uncoupling in Dancers

PubMed Central

Nigmatullina, Yuliya; Hellyer, Peter J.; Nachev, Parashkev; Sharp, David J.; Seemungal, Barry M.

2015-01-01

Sensory input evokes low-order reflexes and higher-order perceptual responses. Vestibular stimulation elicits vestibular-ocular reflex (VOR) and self-motion perception (e.g., vertigo) whose response durations are normally equal. Adaptation to repeated whole-body rotations, for example, ballet training, is known to reduce vestibular responses. We investigated the neuroanatomical correlates of vestibular perceptuo-reflex adaptation in ballet dancers and controls. Dancers' vestibular-reflex and perceptual responses to whole-body yaw-plane step rotations were: (1) Briefer and (2) uncorrelated (controls' reflex and perception were correlated). Voxel-based morphometry showed a selective gray matter (GM) reduction in dancers' vestibular cerebellum correlating with ballet experience. Dancers' vestibular cerebellar GM density reduction was related to shorter perceptual responses (i.e. positively correlated) but longer VOR duration (negatively correlated). Contrastingly, controls' vestibular cerebellar GM density negatively correlated with perception and VOR. Diffusion-tensor imaging showed that cerebral cortex white matter (WM) microstructure correlated with vestibular perception but only in controls. In summary, dancers display vestibular perceptuo-reflex dissociation with the neuronatomical correlate localized to the vestibular cerebellum. Controls' robust vestibular perception correlated with a cortical WM network conspicuously absent in dancers. Since primary vestibular afferents synapse in the vestibular cerebellum, we speculate that a cerebellar gating of perceptual signals to cortical regions mediates the training-related attenuation of vestibular perception and perceptuo-reflex uncoupling. PMID:24072889

Bayesian quantification of sensory reweighting in a familial bilateral vestibular disorder (DFNA9).

PubMed

Alberts, Bart B G T; Selen, Luc P J; Verhagen, Wim I M; Pennings, Ronald J E; Medendorp, W Pieter

2018-03-01

DFNA9 is a rare progressive autosomal dominantly inherited vestibulo-cochlear disorder, resulting in a homogeneous group of patients with hearing impairment and bilateral vestibular function loss. These patients suffer from a deteriorated sense of spatial orientation, leading to balance problems in darkness, especially on irregular surfaces. Both behavioral and functional imaging studies suggest that the remaining sensory cues could compensate for the loss of vestibular information. A thorough model-based quantification of this reweighting in individual patients is, however, missing. Here we psychometrically examined the individual patient's sensory reweighting of these cues after complete vestibular loss. We asked a group of DFNA9 patients and healthy control subjects to judge the orientation (clockwise or counterclockwise relative to gravity) of a rod presented within an oriented square frame (rod-in-frame task) in three different head-on-body tilt conditions. Our results show a cyclical frame-induced bias in perceived gravity direction across a 90° range of frame orientations. The magnitude of this bias was significantly increased in the patients compared with the healthy control subjects. Response variability, which increased with head-on-body tilt, was also larger for the patients. Reverse engineering of the underlying signal properties, using Bayesian inference principles, suggests a reweighting of sensory signals, with an increase in visual weight of 20-40% in the patients. Our approach of combining psychophysics and Bayesian reverse engineering is the first to quantify the weights associated with the different sensory modalities at an individual patient level, which could make it possible to develop personal rehabilitation programs based on the patient's sensory weight distribution. NEW & NOTEWORTHY It has been suggested that patients with vestibular deficits can compensate for this loss by increasing reliance on other sensory cues, although an actual quantification of this reweighting is lacking. We combine experimental psychophysics with a reverse engineering approach based on Bayesian inference principles to quantify sensory reweighting in individual vestibular patients. We discuss the suitability of this approach for developing personal rehabilitation programs based on the patient's sensory weight distribution.

The influence of unilateral saccular impairment on functional balance performance and self-report dizziness.

PubMed

McCaslin, Devin L; Jacobson, Gary P; Grantham, Sarah L; Piker, Erin G; Verghese, Susha

2011-09-01

Postural stability in humans is largely maintained by vestibular, visual, and somatosensory inputs to the central nervous system. Recent clinical advances in the assessment of otolith function (e.g., cervical and ocular vestibular evoked myogenic potentials [cVEMPs and oVEMPs], subjective visual vertical [SVV] during eccentric rotation) have enabled investigators to identify patients with unilateral otolith impairments. This research has suggested that patients with unilateral otolith impairments perform worse than normal healthy controls on measures of postural stability. It is not yet known if patients with unilateral impairments of the saccule and/or inferior vestibular nerve (i.e., unilaterally abnormal cVEMP) perform differently on measures of postural stability than patients with unilateral impairments of the horizontal SCC (semicircular canal) and/or superior vestibular nerve (i.e., unilateral caloric weakness). Further, it is not known what relationship exists, if any, between otolith system impairment and self-report dizziness handicap. The purpose of this investigation was to determine the extent to which saccular impairments (defined by a unilaterally absent cVEMP) and impairments of the horizontal semicircular canal (as measured by the results of caloric testing) affect vestibulospinal function as measured through the Sensory Organization Test (SOT) of the computerized dynamic posturography (CDP). A secondary objective of this investigation was to measure the effects, if any, that saccular impairment has on a modality-specific measure of health-related quality of life. A retrospective cohort study. Subjects were assigned to one of four groups based on results from balance function testing: Group 1 (abnormal cVEMP response only), Group 2 (abnormal caloric response only), Group 3 (abnormal cVEMP and abnormal caloric response), and Group 4 (normal control group). Subjects were 92 adult patients: 62 were seen for balance function testing due to complaints of dizziness, vertigo, or unsteadiness, and 30 served as controls. All subjects underwent videonystagmography or electronystagmography (VNG/ENG), vestibular evoked myogenic potentials (VEMPs), self-report measures of self-perceived dizziness disability/handicap (Dizziness Handicap Inventory), and tests of postural control (Neurocom Equitest). Subjects were categorized into one of four groups based on balance function test results. All variables were subjected to a multifactor analysis of variance (ANOVA). The Dizziness Handicap Inventory (DHI) total scores and equilibrium scores served as the dependent variables. Results showed that patients with abnormal unilateral saccular or inferior vestibular nerve function (i.e., abnormal cVEMP) demonstrated significantly impaired postural control when compared to normal participants. However, this group demonstrated significantly better postural stability when compared to the group with abnormal caloric responses alone and the group with abnormal caloric responses and abnormal cVEMP results. Patients with an abnormal cVEMP did not differ significantly on the DHI compared to the other two impaired groups. We interpret these findings as evidence that a significantly asymmetrical cVEMP in isolation negatively impacts performance on measures of postural control compared to normal subjects but not compared to patients with significant caloric weaknesses. However, patients with a unilaterally abnormal cVEMP do not differ from patients with significant caloric weaknesses in regard to self-perceived dizziness handicap. American Academy of Audiology.

Relation between perception of vertical axis rotation and vestibulo-ocular reflex symmetry

NASA Technical Reports Server (NTRS)

Peterka, Robert J.; Benolken, Martha S.

1991-01-01

Subjects seated in a vertical axis rotation chair controlled their rotational velocity by adjusting a potentiometer. Their goal was to null out pseudorandom rotational perturbations in order to remain perceptually stationary. Most subjects showed a slow linear drift of velocity (a constant acceleration) to one side when they were deprived of an earth-fixed visual reference. The amplitude and direction of this drift can be considered a measure of a static bias in the subject's perception of rotation. The presence of a perceptual bias is consistent with a small, constant imbalance of vestibular function which could be of either central or peripheral origin. Deviations from perfect vestibulocular reflex (VOR) symmetry are also assumed to be related to imbalances in either peripheral or central vestibular function. Researchers looked for correlations between perceptual bias and various measures of vestibular reflex symmetry that might suggest a common source for both reflective and perceptual imbalances. No correlations were found. Measurement errors could not account for these results since repeated tests on the same subjects of both perceptual bias and VOR symmetry were well correlated.

Alternative Splice Forms Influence Functions of Whirlin in Mechanosensory Hair Cell Stereocilia.

PubMed

Ebrahim, Seham; Ingham, Neil J; Lewis, Morag A; Rogers, Michael J C; Cui, Runjia; Kachar, Bechara; Pass, Johanna C; Steel, Karen P

2016-05-03

WHRN (DFNB31) mutations cause diverse hearing disorders: profound deafness (DFNB31) or variable hearing loss in Usher syndrome type II. The known role of WHRN in stereocilia elongation does not explain these different pathophysiologies. Using spontaneous and targeted Whrn mutants, we show that the major long (WHRN-L) and short (WHRN-S) isoforms of WHRN have distinct localizations within stereocilia and also across hair cell types. Lack of both isoforms causes abnormally short stereocilia and profound deafness and vestibular dysfunction. WHRN-S expression, however, is sufficient to maintain stereocilia bundle morphology and function in a subset of hair cells, resulting in some auditory response and no overt vestibular dysfunction. WHRN-S interacts with EPS8, and both are required at stereocilia tips for normal length regulation. WHRN-L localizes midway along the shorter stereocilia, at the level of inter-stereociliary links. We propose that differential isoform expression underlies the variable auditory and vestibular phenotypes associated with WHRN mutations. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Gene mapping of the Usher syndromes.

PubMed

Kimberling, W; Smith, R J

1992-10-01

USH is an autosomal recessive group of diseases characterized by auditory impairment and visual loss owing to RP. Two common types of USH are known, types I and II. USH type I is characterized by a congenital severe to profound hearing impairment, absent vestibular function, and a progressive pigmentary retinopathy. Persons with type I do not find hearing aids useful, have delayed motor development, and experience progressive night blindness and peripheral visual loss, which usually begins in their second decade. USH type II is characterized by a congenital moderate to severe hearing loss with a down-sloping audiogram, normal vestibular function, and a progressive pigmentary retinopathy. Persons with USH2 find hearing aids beneficial, have normal psychomotor development, and experience progressive night blindness and peripheral visual loss, which usually begins in their third decade. Vestibular dysfunction is the best distinguishing hallmark to differentiate USH type I from type II. One USH type II gene (called USH2) has been assigned to chromosome 1q. One USH type I gene has been tentatively assigned to chromosome 14q. There are other USH genes that have not yet been localized.

Effect of 30-min +3 Gz centrifugation on vestibular and autonomic cardiovascular function

NASA Technical Reports Server (NTRS)

Schlegel, Todd T.; Wood, Scott J.; Brown, Troy E.; Harm, Deborah L.; Rupert, A. H.

2003-01-01

INTRODUCTION: Repeated exposure to increased +Gz enhances human baroreflex responsiveness and improves tolerance to cardiovascular stress. However, it is not known whether such enhancements might also result from a single, more prolonged exposure to increased +Gz. Our study was designed to investigate whether baroreflex function and orthostatic tolerance are acutely improved by a single prolonged exposure to +3 Gz, and moreover, whether changes in autonomic cardiovascular function resulting from exposure to increased +Gz are correlated with changes in otolith function. METHODS: We exposed 15 healthy human subjects to +3 Gz centrifugation for up to 30 min or until symptoms of incipient G-induced loss of consciousness (G-LOC) ensued. Tests of autonomic cardiovascular function both before and after centrifugation included: 1) power spectral determinations of beat-to-beat R-R intervals and arterial pressures; 2) carotid-cardiac baroreflex tests; 3) Valsalva tests; and 4) 30-min head-up tilt tests. Otolith function was assessed during centrifugation by the linear vestibulo-ocular reflex and both before and after centrifugation by measurements of ocular counter-rolling and dynamic posturography. RESULTS: Of the 15 subjects who underwent prolonged +3 Gz, 4 were intolerant to 30 min of head-up tilt before centrifugation but became tolerant to such tilt after centrifugation. The Valsalva-related baroreflex as well as a measure of the carotid-cardiac baroreflex were also enhanced after centrifugation. No significant vestibular-autonomic relationships were detected beyond a vestibular-cerebrovascular interaction reported earlier in a subset of seven participants. CONCLUSIONS: A single prolonged exposure to +3 Gz centrifugation acutely improves baroreflex function and orthostatic tolerance.

Balance Screening of Vestibular Function in Subjects Aged 4 Years and Older: A Living Laboratory Experience

PubMed Central

Bermúdez Rey, María Carolina; Clark, Torin K.; Merfeld, Daniel M.

2017-01-01

To better understand the various individual factors that contribute to balance and the relation to fall risk, we performed the modified Romberg Test of Standing Balance on Firm and Compliant Support, with 1,174 participants between 4 and 83 years of age. This research was conducted in the Living Laboratory® at the Museum of Science, Boston. We specifically focus on balance test condition 4, in which individuals stand on memory foam with eyes closed, and must rely on their vestibular system; therefore, performance in this balance test condition provides a proxy for vestibular function. We looked for balance variations associated with sex, race/ethnicity, health factors, and age. We found that balance test performance was stable between 10 and 39 years of age, with a slight increase in the failure rate for participants 4–9 years of age, suggesting a period of balance development in younger children. For participants 40 years and older, the balance test failure rate increased progressively with age. Diabetes and obesity are the two main health factors we found associated with poor balance, with test condition 4 failure rates of 57 and 19%, respectively. An increase in the odds of having fallen in the last year was associated with a decrease in the time to failure; once individuals dropped below a time to failure of 10 s, there was a significant 5.5-fold increase in the odds of having fallen in the last 12 months. These data alert us to screen for poor vestibular function in individuals 40 years and older or suffering from diabetes, in order to undertake the necessary diagnostic and rehabilitation measures, with a focus on reducing the morbidity and mortality of falls. PMID:29234301

Balance Screening of Vestibular Function in Subjects Aged 4 Years and Older: A Living Laboratory Experience.

PubMed

Bermúdez Rey, María Carolina; Clark, Torin K; Merfeld, Daniel M

2017-01-01

To better understand the various individual factors that contribute to balance and the relation to fall risk, we performed the modified Romberg Test of Standing Balance on Firm and Compliant Support, with 1,174 participants between 4 and 83 years of age. This research was conducted in the Living Laboratory ® at the Museum of Science, Boston. We specifically focus on balance test condition 4, in which individuals stand on memory foam with eyes closed, and must rely on their vestibular system; therefore, performance in this balance test condition provides a proxy for vestibular function. We looked for balance variations associated with sex, race/ethnicity, health factors, and age. We found that balance test performance was stable between 10 and 39 years of age, with a slight increase in the failure rate for participants 4-9 years of age, suggesting a period of balance development in younger children. For participants 40 years and older, the balance test failure rate increased progressively with age. Diabetes and obesity are the two main health factors we found associated with poor balance, with test condition 4 failure rates of 57 and 19%, respectively. An increase in the odds of having fallen in the last year was associated with a decrease in the time to failure; once individuals dropped below a time to failure of 10 s, there was a significant 5.5-fold increase in the odds of having fallen in the last 12 months. These data alert us to screen for poor vestibular function in individuals 40 years and older or suffering from diabetes, in order to undertake the necessary diagnostic and rehabilitation measures, with a focus on reducing the morbidity and mortality of falls.

The effect of preterm birth on vestibular evoked myogenic potentials in children.

PubMed

Eshaghi, Zahra; Jafari, Zahra; Shaibanizadeh, Abdolreza; Jalaie, Shohreh; Ghaseminejad, Azizeh

2014-01-01

Preterm birth is a significant global health problem with serious short- and long-term consequences. This study examined the long term effects of preterm birth on vestibular evoked myogenic potentials (VEMPs) among preschool-aged children. Thirty-one children with preterm and 20 children with term birth histories aged 5.5 to 6.5 years were studied. Each child underwent VEMPs testing using a 500 Hz tone-burst stimulus with a 95 dB nHL (normal hearing level) intensity level. The mean peak latencies of the p13 and n23 waves in the very preterm group were significantly longer than for the full-term group (p≤ 0.041). There was a significant difference between very and mildly preterm children in the latency of peak p13 (p= 0.003). No significant differences existed between groups for p13-n23 amplitude and the interaural amplitude difference ratio. The tested ear and gender did not affect the results of the test. Prolonged VEMPs in very preterm children may reflect neurodevelopmental impairment and incomplete maturity of the vestibulospinal tract (sacculocollic reflex pathway), especially myelination. VEMPs is a non-invasive technique for investigating the vestibular function in young children, and considered to be an appropriate tool for evaluating vestibular impairments at the low brainstem level. It can be used in follow-ups of the long-term effects of preterm birth on the vestibular system.

Comparison of Virtual Reality Based Therapy with Customized Vestibular Physical Therapy for the Treatment of Vestibular Disorders

PubMed Central

Alahmari, Khalid A.; Sparto, Patrick J; Marchetti, Gregory F.; Redfern, Mark S.; Furman, Joseph M.; Whitney, Susan L.

2017-01-01

We examined outcomes in persons with vestibular disorders after receiving virtual reality based therapy (VRBT) or customized vestibular physical therapy (PT) as an intervention for habituation of dizziness symptoms. Twenty subjects with vestibular disorders received VRBT and 18 received PT. During the VRBT intervention, subjects walked on a treadmill within an immersive virtual grocery store environment, for 6 sessions approximately one week apart. The PT intervention consisted of gaze stabilization, standing balance and walking exercises individually tailored to each subject. Before, one week after, and at 6-months after the intervention, subjects completed self-report and balance performance measures. Before and after each VRBT session, subjects also reported symptoms of nausea, headache, dizziness, and visual blurring. In both groups, significant improvements were noted on the majority of self-report and performance measures one week after the intervention. Subjects maintained improvements on self report and performance measures at 6 months follow up. There were not between group differences. Nausea, headache, dizziness and visual blurring increased significantly during the VRBT sessions, but overall symptoms were reduced at the end of the six-week intervention. While this study did not find a difference in outcomes between PT and VRBT, the mechanism by which subjects with chronic dizziness demonstrated improvement in dizziness and balance function may be different. PMID:24608691

Vestibular function in patients with Niemann-Pick type C disease.

PubMed

Bremova, Tatiana; Krafczyk, Siegbert; Bardins, Stanislavs; Reinke, Jörg; Strupp, Michael

2016-11-01

We investigated whether vestibular dysfunction may cause or contribute to postural imbalance and falls in patients with Niemann-Pick type C disease (NP-C). Eight patients with NP-C disease and 20 healthy controls were examined using the video-based head impulse test (vHIT) and caloric irrigation to investigate horizontal canal function as well as ocular- and cervical vestibular evoked myogenic potentials (o- and cVEMP), and binocular subjective visual vertical estimation (SVV) for otolith function, and static posturography. There were no significant differences in vestibulo-ocular gain, caloric excitability, o-/cVEMP measures or SVV between the two groups. Posturographic total sway path (tSP) and root mean square (RMS) were significantly higher in NP-C than in controls in 3 out of 4 conditions. The Romberg quotient (RQ) to assess the amount of visual stabilization was significantly lower in the NP-C than in the HC group. In contrast to other inherited metabolic disorders, such as Morbus Gaucher type 3, we did not find any evidence for an impairment of canal or otolith function in patients with NP-C as their cause of postural imbalance. Since RQ was low in NP-C patients, indicating proper sensory input, the observed increased postural sway is most likely due to a cerebellar dysfunction in NP-C, which may therefore, explain postural imbalance.

Trigeminal, Visceral and Vestibular Inputs May Improve Cognitive Functions by Acting through the Locus Coeruleus and the Ascending Reticular Activating System: A New Hypothesis

PubMed Central

De Cicco, Vincenzo; Tramonti Fantozzi, Maria P.; Cataldo, Enrico; Barresi, Massimo; Bruschini, Luca; Faraguna, Ugo; Manzoni, Diego

2018-01-01

It is known that sensory signals sustain the background discharge of the ascending reticular activating system (ARAS) which includes the noradrenergic locus coeruleus (LC) neurons and controls the level of attention and alertness. Moreover, LC neurons influence brain metabolic activity, gene expression and brain inflammatory processes. As a consequence of the sensory control of ARAS/LC, stimulation of a sensory channel may potential influence neuronal activity and trophic state all over the brain, supporting cognitive functions and exerting a neuroprotective action. On the other hand, an imbalance of the same input on the two sides may lead to an asymmetric hemispheric excitability, leading to an impairment in cognitive functions. Among the inputs that may drive LC neurons and ARAS, those arising from the trigeminal region, from visceral organs and, possibly, from the vestibular system seem to be particularly relevant in regulating their activity. The trigeminal, visceral and vestibular control of ARAS/LC activity may explain why these input signals: (1) affect sensorimotor and cognitive functions which are not directly related to their specific informational content; and (2) are effective in relieving the symptoms of some brain pathologies, thus prompting peripheral activation of these input systems as a complementary approach for the treatment of cognitive impairments and neurodegenerative disorders. PMID:29358907

A systematic review of patient-reported outcome measures in clinical vestibular research

PubMed Central

Fong, Eric; Li, Carol; Aslakson, Rebecca; Agrawal, Yuri

2014-01-01

Objective To identify the most commonly-used patient-reported outcome (PRO) measures in clinical vestibular research, and assess their test characteristics and applicability to study age-related vestibular loss (ARVL) in clinical trials. Data Sources We performed a systematic review of the PubMed, CINAHL, and PsycINFO databases from 1950 to August 13, 2013. Study Selection PRO measures were defined as outcomes that capture the subjective experience of the patient, such as symptoms, functional status, health perceptions, and quality of life. Two independent reviewers selected studies that used PRO measures in clinical vestibular research. Disparities were resolved with consensus between the reviewers. Of 2260 articles initially found on literature search, 255 full-text articles were retrieved for assessment. One-hundred and four studies met inclusion criteria for data collection. Data Extraction PRO measures were identified by two independent reviewers. The four most commonly used PROs were evaluated for their applicability to the condition of ARVL. Specifically, for these four PROs, data were collected pertaining to instrument test-retest reliability, item domains, and target population of the instrument. Data Synthesis A total of 50 PRO instruments were identified. The four most frequently utilized PROs were the Dizziness Handicap Inventory (DHI), the Activities-specific Balance Confidence (ABC) scale, the Vertigo Symptom Scale (VSS), and the Visual Analogue Scale (VAS). Of these four PROs, three were validated for use in patients with vestibular disease, and one was validated in community-dwelling older individuals with balance impairments. Items across the four PROs were categorized into three domains based on the International Classification of Functioning, Disability and Health: Activity, Participation, and Body Functions and Structures. Conclusions None of the most commonly-used PRO instruments were validated for use in community-dwelling older adults specifically with ARVL. Nevertheless, the three common domains of items identified across these four PRO instruments may be generalizable to older adults and provide a basis for developing a PRO instrument designed to evaluate the effectiveness of interventions targeted to ARVL. PMID:25305629

Vestibular Stochastic Resonance as a Method to Improve Balance Function: Optimization of Stimulus Characteristics

NASA Technical Reports Server (NTRS)

Mulavara, Ajitkumar; Fiedler, Matthew; Kofman, Igor; Peters, Brian; Wood, Scott; Serrador, Jorge; Cohen, Helen; Reschke, Millard; Bloomberg, Jacob

2010-01-01

Stochastic resonance (SR) is a mechanism by which noise can assist and enhance the response of neural systems to relevant sensory signals. Application of imperceptible SR noise coupled with sensory input through the proprioceptive, visual, or vestibular sensory systems has been shown to improve motor function. Specifically, studies have shown that that vestibular electrical stimulation by imperceptible stochastic noise, when applied to normal young and elderly subjects, significantly improved their ocular stabilization reflexes in response to whole-body tilt as well as balance performance during postural disturbances. The goal of this study was to optimize the characteristics of the stochastic vestibular signals for balance performance during standing on an unstable surface. Subjects performed a standardized balance task of standing on a block of 10 cm thick medium density foam with their eyes closed for a total of 40 seconds. Stochastic electrical stimulation was applied to the vestibular system through electrodes placed over the mastoid process behind the ears during the last 20 seconds of the test period. A custom built constant current stimulator with subject isolation delivered the stimulus. Stimulation signals were generated with frequencies in the bandwidth of 1-2 Hz and 0.01-30 Hz. Amplitude of the signals were varied in the range of 0- +/-700 micro amperes with the RMS of the signal increased by 30 micro amperes for each 100 micro amperes increase in the current range. Balance performance was measured using a force plate under the foam block and inertial motion sensors placed on the torso and head segments. Preliminary results indicate that balance performance is improved in the range of 10-25% compared to no stimulation conditions. Subjects improved their performance consistently across the blocks of stimulation. Further the signal amplitude at which the performance was maximized was different in the two frequency ranges. Optimization of the frequency and amplitude of the signal characteristics of the stochastic noise signals on maximizing balance performance will have a significant impact in its development as a unique system to aid recovery of function in astronauts after long duration space flight or for people with balance disorders.

Static and dynamic posture control in postlingual cochlear implanted patients: effects of dual-tasking, visual and auditory inputs suppression

PubMed Central

Bernard-Demanze, Laurence; Léonard, Jacques; Dumitrescu, Michel; Meller, Renaud; Magnan, Jacques; Lacour, Michel

2014-01-01

Posture control is based on central integration of multisensory inputs, and on internal representation of body orientation in space. This multisensory feedback regulates posture control and continuously updates the internal model of body's position which in turn forwards motor commands adapted to the environmental context and constraints. The peripheral localization of the vestibular system, close to the cochlea, makes vestibular damage possible following cochlear implant (CI) surgery. Impaired vestibular function in CI patients, if any, may have a strong impact on posture stability. The simple postural task of quiet standing is generally paired with cognitive activity in most day life conditions, leading therefore to competition for attentional resources in dual-tasking, and increased risk of fall particularly in patients with impaired vestibular function. This study was aimed at evaluating the effects of postlingual cochlear implantation on posture control in adult deaf patients. Possible impairment of vestibular function was assessed by comparing the postural performance of patients to that of age-matched healthy subjects during a simple postural task performed in static (stable platform) and dynamic (platform in translation) conditions, and during dual-tasking with a visual or auditory memory task. Postural tests were done in eyes open (EO) and eyes closed (EC) conditions, with the CI activated (ON) or not (OFF). Results showed that the postural performance of the CI patients strongly differed from the controls, mainly in the EC condition. The CI patients showed significantly reduced limits of stability and increased postural instability in static conditions. In dynamic conditions, they spent considerably more energy to maintain equilibrium, and their head was stabilized neither in space nor on trunk: they behaved dynamically without vision like an inverted pendulum while the controls showed a whole body rigidification strategy. Hearing (prosthesis on) as well as dual-tasking did not really improve the dynamic postural performance of the CI patients. We conclude that CI patients become strongly visual dependent mainly in challenging postural conditions, a result they have to be awarded of particularly when getting older. PMID:24474907

Static and dynamic posture control in postlingual cochlear implanted patients: effects of dual-tasking, visual and auditory inputs suppression.

PubMed

Bernard-Demanze, Laurence; Léonard, Jacques; Dumitrescu, Michel; Meller, Renaud; Magnan, Jacques; Lacour, Michel

2013-01-01

Posture control is based on central integration of multisensory inputs, and on internal representation of body orientation in space. This multisensory feedback regulates posture control and continuously updates the internal model of body's position which in turn forwards motor commands adapted to the environmental context and constraints. The peripheral localization of the vestibular system, close to the cochlea, makes vestibular damage possible following cochlear implant (CI) surgery. Impaired vestibular function in CI patients, if any, may have a strong impact on posture stability. The simple postural task of quiet standing is generally paired with cognitive activity in most day life conditions, leading therefore to competition for attentional resources in dual-tasking, and increased risk of fall particularly in patients with impaired vestibular function. This study was aimed at evaluating the effects of postlingual cochlear implantation on posture control in adult deaf patients. Possible impairment of vestibular function was assessed by comparing the postural performance of patients to that of age-matched healthy subjects during a simple postural task performed in static (stable platform) and dynamic (platform in translation) conditions, and during dual-tasking with a visual or auditory memory task. Postural tests were done in eyes open (EO) and eyes closed (EC) conditions, with the CI activated (ON) or not (OFF). Results showed that the postural performance of the CI patients strongly differed from the controls, mainly in the EC condition. The CI patients showed significantly reduced limits of stability and increased postural instability in static conditions. In dynamic conditions, they spent considerably more energy to maintain equilibrium, and their head was stabilized neither in space nor on trunk: they behaved dynamically without vision like an inverted pendulum while the controls showed a whole body rigidification strategy. Hearing (prosthesis on) as well as dual-tasking did not really improve the dynamic postural performance of the CI patients. We conclude that CI patients become strongly visual dependent mainly in challenging postural conditions, a result they have to be awarded of particularly when getting older.

Effect of Sustained Human Centrifugation on Autonomic Cardiovascular and Vestibular Function

NASA Technical Reports Server (NTRS)

Schlegel, Todd T.; Wood, Scott J.; Brown, Troy E.; Benavides, Edgar W.; Harm, Deborah L.; Rupert, A. H.

2002-01-01

Repeated exposure to +Gz enhances human baroreflex responsiveness and improves tolerance to cardiovascular stress. However, both sustained exposure to +Gx and changes in otolith function resulting from the gravitational changes of space flight and parabolic flight may adversely affect autonomic cardiovascular function and orthostatic tolerance. HYPOTHESES: Baroreflex function and orthostatic tolerance are acutely improved by a single sustained (30 min) exposure to +3Gz but not +3Gx. Moreover, after 30 min of +3Gx, any changes that occur in autonomic cardiovascular function will relate commensurately to changes in otolith function. METHODS: Twenty-two healthy human subjects were first exposed to 5 min of +3 Gz centrifugation and then subsequently up to a total of30 min of either +3Gz (n = 15) or +3Gx (n = 7) centrifugation. Tests of autonomic cardiovascular function both before and after both types of centrifugation included: (a) power spectral determinations of beat-to-beat R-R intervals and arterial pressures; (b) carotid-cardiac baroreflex tests; ( c) Valsalva tests; and (d) 30-min head-up tilt (HUT) tests. Otolith function was assessed during centrifugation by the linear vestibulo-ocular reflex and both before and after centrifugation by measurements of ocular counter-rolling and dynamic posturography. RESULTS: All four +3Gz subjects who were intolerant to HUT before centrifugation became tolerant to HUT after centrifugation. The operational point of the carotid-cardiac baroreflex and the Valsalva-related baroreflex were also enhanced in the +3Gz group but not in the +3Gx group. No significant vestibular-autonomic relationships were detected, other than a significant vestibular-cerebrovascular interaction reported previously. CONCLUSIONS: A single, sustained exposure to +3 Gz centrifugation acutely improves baroreflex function and orthostatic tolerance whereas a similar exposure to +3 Gx centrifugation appears to have less effect.

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

PubMed Central

Fukushima, Kikuro; Fukushima, Junko; Warabi, Tateo

2011-01-01

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 canceling 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. PMID:22174706

Effects of Vestibular Loss on Orthostatic Responses to Tilts in the Pitch Plane

NASA Technical Reports Server (NTRS)

Wood, Scott J.; Serrador, Jorge M.; Black, F. Owen; Rupert,Angus H.; Schlegel, Todd T.

2004-01-01

The purpose of this study was to determine the extent to which vestibular loss might impair orthostatic responses to passive tilts in the pitch plane in human subjects. Data were obtained from six subjects having chronic bilateral vestibular loss and six healthy individuals matched for age, gender, and body mass index. Vestibular loss was assessed with a comprehensive battery including dynamic posturography, vestibulo-ocular and optokinetic reflexes, vestibular evoked myogenic potentials, and ocular counterrolling. Head up tilt tests were conducted using a motorized two-axis table that allowed subjects to be tilted in the pitch plane from either a supine or prone body orientation at a slow rate (8 deg/s). The sessions consisted of three tilts, each consisting of20 min rest in a horizontal position, tilt to 80 deg upright for 10 min, and then return to the horizontal position for 5 min. The tilts were performed in darkness (supine and prone) or in light (supine only). Background music was used to mask auditory orientation cues. Autonomic measurements included beat-to-beat recordings of blood pressure (Finapres), heart rate (ECG), cerebral blood flow velocity in the middle cerebral artery (transcranial Doppler), end tidal CO2, respiratory rate and volume (Respritrace), and stroke volume (impedance cardiography). For both patients and control subjects, cerebral blood flow appeared to exhibit the most rapid adjustment following transient changes in posture. Outside of a greater cerebral hypoperfusion in patients during the later stages of tilt, responses did not differ dramatically between the vestibular loss and control subjects, or between tilts performed in light and dark room conditions. Thus, with the 'exception of cerebrovascular regulation, we conclude that orthostatic responses during slow postural tilts are not substantially impaired in humans following chronic loss of vestibular function, a result that might reflect compensation by nonvisual graviceptor inputs (e.g., somatosensory) or other circulatory reflex mechanisms.

[The application of subjective visual gravity in assessment of vestibular compensation: a pilot study].

PubMed

Zhao, Yuan; Chen, Taisheng; Wang, Wei; Xu, Kaixu; Wen, Chao; Liu, Qiang; Han, Xi; Li, Shanshan; Li, Xiaojie; Lin, Peng

2016-05-01

To discuss the characteristics of subjective visual gravity (subjective visual vertical/horizontal, SVV/SVH) and assess its clinical application for peripheral unilateral vestibular compensation. 69 cases of acute peripheral unilateral vestibular dysfunction patients (case group) accepted SVV/SVH, spontaneous nystagmus (SN), caloric test (CT) and other vestibular function tests. 49 healthy people (control group) accepted SVV/SVH only. SVV/SVH, SN and unilateral weakness (UW) were selected as for the observation indicators. The correlations between SVV/SVH, SN, UW and courses were investigated respectively, as well as the characteristic of SVV/SVH, SN in period of vestibular compensation. Among case group SVV, SVH positive in 42 patients(60.9%) and 44 patients(63.8%), the absolute values of the skew angle were in the range between 2.1°-20.0°, 2.1°-22.2°. Skew angles of SVV/SVH in control were in the range between -1.5°-2.0° and -2.0°-1.6°, and had no statistical significance with case group(t=5.336 and 5.864, P<0.05). SN-positive 28 cases (40.6%), the range of intensities at 2.4°-17.1°; UW-positive 50 cases (72.5%). In case group, positive correlation between SVV and SVH(r=0.948, P=0.00), negatively correlated between SVV/SVH and SN respectively(r values were -0.720, -0.733, P values were 0.00), no correlation between the skew angle of SVV/SVH, strength of SN and UW value(r values were 0.191, 0.189, and 0.179, P>0.05), there was no correlation between the absolute value of SVV, SVH, SN, UW with the duration (rs values were -0.075, -0.065, -0.212, and 0.126, P>0.05). Subjective visual gravity can be used not only to assess the range of unilateral peripheral vestibular dysfunction, but also help assess the static compensatory of otolithic, guidance and assessment of vestibular rehabilitation.

Influence of Sensory Dependence on Postural Control

NASA Technical Reports Server (NTRS)

Santana, Patricia A.; Mulavara, Ajitkumar P.; Fiedler, Matthew J.

2011-01-01

The current project is part of an NSBRI funded project, "Development of Countermeasures to Aid Functional Egress from the Crew Exploration Vehicle Following Long-Duration Spaceflight." The development of this countermeasure is based on the use of imperceptible levels of electrical stimulation to the balance organs of the inner ear to assist and enhance the response of a person s sensorimotor function. These countermeasures could be used to increase an astronaut s re-adaptation rate to Earth s gravity following long-duration space flight. The focus of my project is to evaluate and examine the correlation of sensory preferences for vision and vestibular systems. Disruption of the sensorimotor functions following space flight affects posture, locomotion and spatial orientation tasks in astronauts. The Group Embedded Figures Test (GEFT), the Rod and Frame Test (RFT) and the Computerized Dynamic Posturography Test (CDP) are measurements used to examine subjects visual and vestibular sensory preferences. The analysis of data from these tasks will assist in relating the visual dependence measures recognized in the GEFT and RFT with vestibular dependence measures recognized in the stability measures obtained during CDP. Studying the impact of sensory dependence on the performance in varied tasks will help in the development of targeted countermeasures to help astronauts readapt to gravitational changes after long duration space flight.

Traumatic brain injury and vestibulo-ocular function: current challenges and future prospects

PubMed Central

Wallace, Bridgett; Lifshitz, Jonathan

2016-01-01

Normal function of the vestibulo-ocular reflex (VOR) coordinates eye movement with head movement, in order to provide clear vision during motion and maintain balance. VOR is generated within the semicircular canals of the inner ear to elicit compensatory eye movements, which maintain stability of images on the fovea during brief, rapid head motion, otherwise known as gaze stability. Normal VOR function is necessary in carrying out activities of daily living (eg, walking and riding in a car) and is of particular importance in higher demand activities (eg, sports-related activities). Disruption or damage in the VOR can result in symptoms such as movement-related dizziness, blurry vision, difficulty maintaining balance with head movements, and even nausea. Dizziness is one of the most common symptoms following traumatic brain injury (TBI) and is considered a risk factor for a prolonged recovery. Assessment of the vestibular system is of particular importance following TBI, in conjunction with oculomotor control, due to the intrinsic neural circuitry that exists between the ocular and vestibular systems. The purpose of this article is to review the physiology of the VOR and the visual-vestibular symptoms associated with TBI and to discuss assessment and treatment guidelines for TBI. Current challenges and future prospects will also be addressed. PMID:28539811

Multisensory effects on somatosensation: a trimodal visuo-vestibular-tactile interaction

PubMed Central

Kaliuzhna, Mariia; Ferrè, Elisa Raffaella; Herbelin, Bruno; Blanke, Olaf; Haggard, Patrick

2016-01-01

Vestibular information about self-motion is combined with other sensory signals. Previous research described both visuo-vestibular and vestibular-tactile bilateral interactions, but the simultaneous interaction between all three sensory modalities has not been explored. Here we exploit a previously reported visuo-vestibular integration to investigate multisensory effects on tactile sensitivity in humans. Tactile sensitivity was measured during passive whole body rotations alone or in conjunction with optic flow, creating either purely vestibular or visuo-vestibular sensations of self-motion. Our results demonstrate that tactile sensitivity is modulated by perceived self-motion, as provided by a combined visuo-vestibular percept, and not by the visual and vestibular cues independently. We propose a hierarchical multisensory interaction that underpins somatosensory modulation: visual and vestibular cues are first combined to produce a multisensory self-motion percept. Somatosensory processing is then enhanced according to the degree of perceived self-motion. PMID:27198907

Exhibition of Stochastic Resonance in Vestibular Perception

NASA Technical Reports Server (NTRS)

Galvan-Garza, R. C.; Clark, T. K.; Merfeld, D. M.; Bloomberg, J. J.; Oman, C. M.; Mulavara, A. P.

2016-01-01

Astronauts experience sensorimotor changes during spaceflight, particularly during G-transitions. Post flight sensorimotor changes include spatial disorientation, along with postural and gait instability that may degrade operational capabilities of the astronauts and endanger the crew. A sensorimotor countermeasure that mitigates these effects would improve crewmember safety and decrease risk. The goal of this research is to investigate the potential use of stochastic vestibular stimulation (SVS) as a technology to improve sensorimotor function. We hypothesize that low levels of SVS will improve sensorimotor perception through the phenomenon of stochastic resonance (SR), when the response of a nonlinear system to a weak input signal is enhanced by the application of a particular nonzero level of noise. This study aims to advance the development of SVS as a potential countermeasure by 1) demonstrating the exhibition of stochastic resonance in vestibular perception, a vital component of sensorimotor function, 2) investigating the repeatability of SR exhibition, and 3) determining the relative contribution of the semicircular canals (SCC) and otolith (OTO) organs to vestibular perceptual SR. A constant current stimulator was used to deliver bilateral bipolar SVS via electrodes placed on each of the mastoid processes, as previously done. Vestibular perceptual motion recognition thresholds were measured using a 6-degree of freedom MOOG platform and a 150 trial 3-down/1-up staircase procedure. In the first test session, we measured vestibular perceptual thresholds in upright roll-tilt at 0.2 Hz (SCC+OTO) with SVS ranging from 0-700 µA. In a second test session a week later, we re-measured roll-tilt thresholds with 0, optimal (from test session 1), and 1500 µA SVS levels. A subset of these subjects, plus naive subjects, participated in two additional test sessions in which we measured thresholds in supine roll-rotation at 0.2 Hz (SCC) and upright y-translation at 1 Hz (OTO) with SVS up to 700 µA. A sinusoidal galvanic vestibular stimulation (GVS) perceptual threshold was also measured on each test day and used to normalize the SVS levels across subjects. In roll-tilt thresholds with SVS, the characteristic SR curve was qualitatively exhibited in 10 of 12 subjects, and the improvement in motion threshold was significant in 6 subjects, indicating that optimal SVS improved passive body motion perception in a way that is consistent with classical SR theory. A probabilistic comparison to numeric simulations further validated these experimental results. On the second test session, 4 out of the 10 SR exhibitors showed repeated improvement with SVS compared to the no SVS condition. Data collection is ongoing for the last two test sessions in which SCC and OTO only perceptual motion recognition thresholds are being measured with SVS. The final results of these test sessions will give insight into whether vestibular perceptual SR can occur when only one type of vestibular sensor is sensing motion or if it is more evident when sensory integration between the SCC and OTO is occurring during the motion. The overall purpose of this research is to further quantify the effects of SVS on various sensorimotor tasks and to gain a more fundamental understanding of how SVS causes SR in the vestibular system. In the context of human space flight, results from this research will help in understanding how SVS may be practically implemented in the future as a component of a comprehensive countermeasure plan for G-transition adaptation.

The role of vestibular and support-tactile-proprioceptive inputs in visual-manual tracking

NASA Astrophysics Data System (ADS)

Kornilova, Ludmila; Naumov, Ivan; Glukhikh, Dmitriy; Khabarova, Ekaterina; Pavlova, Aleksandra; Ekimovskiy, Georgiy; Sagalovitch, Viktor; Smirnov, Yuriy; Kozlovskaya, Inesa

Sensorimotor disorders in weightlessness are caused by changes of functioning of gravity-dependent systems, first of all - vestibular and support. The question arises, what’s the role and the specific contribution of the support afferentation in the development of observed disorders. To determine the role and effects of vestibular, support, tactile and proprioceptive afferentation on characteristics of visual-manual tracking (VMT) we conducted a comparative analysis of the data obtained after prolonged spaceflight and in a model of weightlessness - horizontal “dry” immersion. Altogether we examined 16 Russian cosmonauts before and after prolonged spaceflights (129-215 days) and 30 subjects who stayed in immersion bath for 5-7 days to evaluate the state of the vestibular function (VF) using videooculography and characteristics of the visual-manual tracking (VMT) using electrooculography & joystick with biological visual feedback. Evaluation of the VF has shown that both after immersion and after prolonged spaceflight there were significant decrease of the static torsional otolith-cervical-ocular reflex (OCOR) and simultaneous significant increase of the dynamic vestibular-cervical-ocular reactions (VCOR) with a revealed negative correlation between parameters of the otoliths and canals reactions, as well as significant changes in accuracy of perception of the subjective visual vertical which correlated with changes in OCOR. Analyze of the VMT has shown that significant disorders of the visual tracking (VT) occurred from the beginning of the immersion up to 3-4 day after while in cosmonauts similar but much more pronounced oculomotor disorders and significant changes from the baseline were observed up to R+9 day postflight. Significant changes of the manual tracking (MT) were revealed only for gain and occurred on 1 and 3 days in immersion while after spaceflight such changes were observed up to R+5 day postflight. We found correlation between characteristics of the VT and MT, between characteristics of the VF and VT and no correlation between VF and MT. It was found that removal of the support and minimization of the proprioceptive afferentation has a greater impact upon accuracy of the VT then accuracy of the MT. Hand tracking accuracy was higher than the eyes for all subjects. The hand’ motor coordination was more stable to changes in support-proprioceptive afferentation then visual tracking. The observed changes in and after immersion are similar but less pronounced with changes observed on cosmonauts after prolonged spaceflight. Keywords: visual-manual tracking, vestibular function, weightlessness, immersion.

Development of utricular otoliths, but not saccular otoliths, is necessary for vestibular function and survival in zebrafish

NASA Technical Reports Server (NTRS)

Riley, B. B.; Moorman, S. J.

2000-01-01

We have been studying the consequences of embryonic vestibular dysfunction caused by the monolith (mnl) mutation in zebrafish. mnl is a dominant mutation that specifically inhibits formation of utricular otoliths. However, briefly immobilizing mnl/mnl embryos in agarose with the otic vesicle orientated at certain angles selectively induces or prevents formation of utricular and/or saccular otoliths. With this noninvasive technique, we generated six phenotypic classes of mnl/mnl mutants, designated S-S, U-U, U-S, S-US, U-US, and US-US, depending on which otoliths are present on each side (U, utricular otolith; S, saccular otolith). All mnl/mnl larvae survived through day 10 of development. Thereafter, S-S larvae showed a rapid decline, probably because of starvation, and none survived to adulthood. Survival rates in all other classes of mnl/mnl larvae (those having at least one utricular otolith) were close to normal. The presence or absence of utricular otoliths also correlated with vestibular function during early larval development, as measured by three criteria: First, unlike wild-type larvae, S-S mutant larvae showed almost no detectable counter-rotation of the eyes when tilted tail up or tail down. Second, 95% of S-S mutant larvae never acquired the ability to maintain a balanced dorsal-up posture. Third, although most wild-type larvae responded to gentle prodding by swimming in a straight line, S-S larvae responded by swimming in rapid circles, showing sudden and frequent changes in direction ("zigzagging"), and/or rolling and spiraling. All other phenotypic classes of mnl/mnl larvae behaved normally in these assays. These data demonstrate that bilateral loss of utricular otoliths disrupts the ability to sense gravity, severely impairs balance and motor coordination, and is invariably lethal. The presence of a utricular otolith in at least one inner ear is necessary and sufficient for vestibular function and survival. In contrast, saccular otoliths are dispensable for these functions. Copyright 2000 John Wiley & Sons, Inc.

Effect of 12-Day Spaceflight on Brain of Thick-Toed Geckos

NASA Astrophysics Data System (ADS)

Proshchina, A. E.; Karlamova, A. S.; Barabanovet, V. M.; Godovalova, O. S.; Guilimova, V. I.; Krivova, Y. S.; Makarov, A. N.; Nikitin, V. B.; Savelieva, E. S.; Saveliev, S. V.

2008-06-01

In the frames of Russian-American joint space experiment onboard Foton-M3 satellite there was undertaken a study of spaceflight influence on brain of the thick-toed gecko (Pachydactylus turneri Gray, 1864). Serial brain sections were stained according to Nissl and also the immunohistochemical method with antibodies to NGF-receptor (p75NGFR), CD95 (also known as Fas and APO-1), glial fibrillary acidic protein (GFAP) and transferrin-receptor (CD71). Detailed examination of the sections of rhombencephalon revealed cytological changes in the neuron bodies of vestibular nuclei inside the flight group. Immunohistochemicaly we found the increase density of CD95 and p75NGFR and decrease of GFAP expression in medial cortex and epithalamus in flight group compared both control.

The Neurovestibular Challenges of Astronauts and Balance Patients: Some Past Countermeasures and Two Alternative Approaches to Elicitation, Assessment and Mitigation

PubMed Central

Lawson, Ben D.; Rupert, Angus H.; McGrath, Braden J.

2016-01-01

Astronauts and vestibular patients face analogous challenges to orientation function due to adaptive exogenous (weightlessness-induced) or endogenous (pathology-induced) alterations in the processing of acceleration stimuli. Given some neurovestibular similarities between these challenges, both affected groups may benefit from shared research approaches and adaptation measurement/improvement strategies. This article reviews various past strategies and introduces two plausible ground-based approaches, the first of which is a method for eliciting and assessing vestibular adaptation-induced imbalance. Second, we review a strategy for mitigating imbalance associated with vestibular pathology and fostering readaptation. In discussing the first strategy (for imbalance assessment), we review a pilot study wherein imbalance was elicited (among healthy subjects) via an adaptive challenge that caused a temporary/reversible disruption. The surrogate vestibular deficit was caused by a brief period of movement-induced adaptation to an altered (rotating) gravitoinertial frame of reference. This elicited adaptation and caused imbalance when head movements were made after reentry into the normal (non-rotating) frame of reference. We also review a strategy for fall mitigation, viz., a prototype tactile sway feedback device for aiding balance/recovery after disruptions caused by vestibular pathology. We introduce the device and review a preliminary exploration of its effectiveness in aiding clinical balance rehabilitation (discussing the implications for healthy astronauts). Both strategies reviewed in this article represent cross-disciplinary research spin-offs: the ground-based vestibular challenge and tactile cueing display were derived from aeromedical research to benefit military aviators suffering from flight simulator-relevant aftereffects or inflight spatial disorientation, respectively. These strategies merit further evaluation using clinical and astronaut populations. PMID:27920669

The Neurovestibular Challenges of Astronauts and Balance Patients: Some Past Countermeasures and Two Alternative Approaches to Elicitation, Assessment and Mitigation.

PubMed

Lawson, Ben D; Rupert, Angus H; McGrath, Braden J

2016-01-01

Astronauts and vestibular patients face analogous challenges to orientation function due to adaptive exogenous (weightlessness-induced) or endogenous (pathology-induced) alterations in the processing of acceleration stimuli. Given some neurovestibular similarities between these challenges, both affected groups may benefit from shared research approaches and adaptation measurement/improvement strategies. This article reviews various past strategies and introduces two plausible ground-based approaches, the first of which is a method for eliciting and assessing vestibular adaptation-induced imbalance. Second, we review a strategy for mitigating imbalance associated with vestibular pathology and fostering readaptation. In discussing the first strategy (for imbalance assessment), we review a pilot study wherein imbalance was elicited (among healthy subjects) via an adaptive challenge that caused a temporary/reversible disruption. The surrogate vestibular deficit was caused by a brief period of movement-induced adaptation to an altered (rotating) gravitoinertial frame of reference. This elicited adaptation and caused imbalance when head movements were made after reentry into the normal (non-rotating) frame of reference. We also review a strategy for fall mitigation, viz., a prototype tactile sway feedback device for aiding balance/recovery after disruptions caused by vestibular pathology. We introduce the device and review a preliminary exploration of its effectiveness in aiding clinical balance rehabilitation (discussing the implications for healthy astronauts). Both strategies reviewed in this article represent cross-disciplinary research spin-offs: the ground-based vestibular challenge and tactile cueing display were derived from aeromedical research to benefit military aviators suffering from flight simulator-relevant aftereffects or inflight spatial disorientation, respectively. These strategies merit further evaluation using clinical and astronaut populations.

The development of the ICF vestibular environmental scale.

PubMed

Whitney, Susan L; Alghadir, Ahmad; Alghwiri, Alia; Alshebber, Kefah M; Alshehri, Mohammed; Furman, Joseph M; Mueller, Martin; Grill, Eva

2016-07-02

People with vestibular disorders report changes in symptoms based on their environment with many situations increasing their symptoms. The purpose of this paper was to utilize the International Classification of Functioning Disability and Health (ICF) from the World Health Organization (WHO) to describe common environmental triggers for dizziness in persons living with balance and vestibular disorders. A multi-centre cross-sectional study was conducted with four different centres on three different continents, including patients from the United States (Pittsburgh), Germany (Munich), Jordan (Amman) and Saudi Arabia (Riyadh). Three hundred eighty one persons with vestibular disorders participated. A 9-item questionnaire (the Vestibular Environmental Scale) was developed from existing ICF items, which were compared to Dizziness Handicap Inventory (DHI) scores. Sixty-five percent of participants reported that "quick movements in the vicinity" increased symptoms, "crowds" at 45%, and "design of buildings, e.g. narrow hallways, stairs, elevators" at 42%. The "crowds" item was a good positive predictor of psychogenic vertigo (OR 1.8, 95% Confidence Interval 1.03-3.16), while "food" (OR 0.47, 95% Confidence Interval 0.17-1.29) and "light" (OR 0.41 95% Confidence Interval 0.23-0.75) were negative predictors of psychogenic vertigo. There also was a positive correlation between the number of triggers and DHI score (Spearman correlation coefficient 0.47, p < 0.0001). Sixty-eight percent of the subjects reported an increase in symptoms with between 1 and 4 environmental triggers. In our cross cultural sample, environmental triggers affect dizziness in persons living with balance and vestibular disorders. The use of items from the ICF of the WHO may help to promote cross cultural sharing of information in persons with dizziness.

HASHIMOTO THYROIDITIS AND VESTIBULAR DYSFUNCTION.

PubMed

Chiarella, Giuseppe; Russo, Diego; Monzani, Fabio; Petrolo, Claudio; Fattori, Bruno; Pasqualetti, Giuseppe; Cassandro, Ettore; Costante, Giuseppe

2017-07-01

The aim of this review was to analyze the existing literature concerning the relationship between Hashimoto thyroiditis (HT) and vestibular dysfunction. We used electronic databases (PubMed, EMBASE, Cochrane Library) to search and collect all published articles about the association between HT and vestibular disorders. Several observational and retrospective studies have postulated a relationship between thyroid autoimmunity and vestibular disorders. In most cases, an appropriate control group was lacking, and the impact of thyroid functional status could not precisely be established. In recent years, two well-designed prospective studies have provided convincing evidence that the association is not random. One article reported that patients with Ménière disease (MD) had a significantly higher prevalence of positive anti-thyroid autoantibody as compared to healthy controls. Moreover, more than half of MD patients had either positive anti-thyroid or non-organ-specific autoantibody titers, compared to less than 30% of both patients with unilateral vestibular paresis without cochlear involvement and healthy controls. Another study found that patients with benign paroxysmal positional vertigo (BPPV) had significantly higher serum thyroid-stimulating hormone and antithyroid autoantibody levels than healthy controls. Additionally, almost one-fifth of euthyroid patients with HT had signs of BPPV. The published results indicate that patients with MD or BPPV are potential candidates to also develop HT. Thus, in HT patients, the presence of even slight symptoms or signs potentially related to vestibular lesions should be carefully investigated. AITD = autoimmune thyroid disease; BPPV = benign paroxysmal positional vertigo; EH = endolymphatic hydrops; HT = Hashimoto thyroiditis; L-T 4 = L-thyroxine; MD = Ménière disease; PS = Pendred syndrome; Tg = thyroglobulin; TPO = thyroid peroxidase; TSH = thyroid-stimulating hormone.

Statistics of the vestibular input experienced during natural self-motion: implications for neural processing.

PubMed

Carriot, Jérome; Jamali, Mohsen; Chacron, Maurice J; Cullen, Kathleen E

2014-06-11

It is widely believed that sensory systems are optimized for processing stimuli occurring in the natural environment. However, it remains unknown whether this principle applies to the vestibular system, which contributes to essential brain functions ranging from the most automatic reflexes to spatial perception and motor coordination. Here we quantified, for the first time, the statistics of natural vestibular inputs experienced by freely moving human subjects during typical everyday activities. Although previous studies have found that the power spectra of natural signals across sensory modalities decay as a power law (i.e., as 1/f(α)), we found that this did not apply to natural vestibular stimuli. Instead, power decreased slowly at lower and more rapidly at higher frequencies for all motion dimensions. We further establish that this unique stimulus structure is the result of active motion as well as passive biomechanical filtering occurring before any neural processing. Notably, the transition frequency (i.e., frequency at which power starts to decrease rapidly) was lower when subjects passively experienced sensory stimulation than when they actively controlled stimulation through their own movement. In contrast to signals measured at the head, the spectral content of externally generated (i.e., passive) environmental motion did follow a power law. Specifically, transformations caused by both motor control and biomechanics shape the statistics of natural vestibular stimuli before neural processing. We suggest that the unique structure of natural vestibular stimuli will have important consequences on the neural coding strategies used by this essential sensory system to represent self-motion in everyday life. Copyright © 2014 the authors 0270-6474/14/348347-11$15.00/0.

The adequate stimulus for avian short latency vestibular responses to linear translation

NASA Technical Reports Server (NTRS)

Jones, T. A.; Jones, S. M.; Colbert, S.

1998-01-01

Transient linear acceleration stimuli have been shown to elicit eighth nerve vestibular compound action potentials in birds and mammals. The present study was undertaken to better define the nature of the adequate stimulus for neurons generating the response in the chicken (Gallus domesticus). In particular, the study evaluated the question of whether the neurons studied are most sensitive to the maximum level of linear acceleration achieved or to the rate of change in acceleration (da/dt, or jerk). To do this, vestibular response thresholds were measured as a function of stimulus onset slope. Traditional computer signal averaging was used to record responses to pulsed linear acceleration stimuli. Stimulus onset slope was systematically varied. Acceleration thresholds decreased with increasing stimulus onset slope (decreasing stimulus rise time). When stimuli were expressed in units of jerk (g/ms), thresholds were virtually constant for all stimulus rise times. Moreover, stimuli having identical jerk magnitudes but widely varying peak acceleration levels produced virtually identical responses. Vestibular response thresholds, latencies and amplitudes appear to be determined strictly by stimulus jerk magnitudes. Stimulus attributes such as peak acceleration or rise time alone do not provide sufficient information to predict response parameter quantities. Indeed, the major response parameters were shown to be virtually independent of peak acceleration levels or rise time when these stimulus features were isolated and considered separately. It is concluded that the neurons generating short latency vestibular evoked potentials do so as "jerk encoders" in the chicken. Primary afferents classified as "irregular", and which traditionally fall into the broad category of "dynamic" or "phasic" neurons, would seem to be the most likely candidates for the neural generators of short latency vestibular compound action potentials.

Different metabotropic glutamate receptors play opposite roles in synaptic plasticity of the rat medial vestibular nuclei

PubMed Central

Grassi, Silvarosa; Frondaroli, Adele; Pettorossi, Vito Enrico

2002-01-01

In the medial vestibular nuclei (MVN) of rat brainstem slices, the role of group II and III metabotropic glutamate receptors (mGluRs) and of the subtypes of group I mGluRs: mGluR1, mGluR5, was investigated in basal synaptic transmission and in the induction and maintenance of long-term potentiation (LTP). We used selective antagonists and agonists for mGluRs and we analysed the field potentials evoked by vestibular afferent stimulation before and after high-frequency stimulation (HFS) to induce LTP. The group II and III mGluR antagonist, (R,S)-α-2-methyl-4sulphonophenylglycine (MSPG), induced LTP per se and caused a reduction of the paired-pulse facilitation (PPF) ratio indicating an enhancement of glutamate release. This suggests that group II and III mGluRs are activated under basal conditions to limit glutamate release. Both the group II and III mGluR selective antagonists, 2S-2-amino-2-(1S,2S-2-carboxycycloprop-1-yl)-3-(xanth-9-yl)propanoate (LY341495) and (R,S)-α-methylserine-O-phosphate (MSOP), induced LTP, and the selective agonists, (2R,4R)-4-aminopyrrolidine-2,4-dicarboxylate (APDC) and L(+)-2-amino-4-phosphonobutyric acid (L-AP4) depressed the field potentials and prevented HFS-LTP, with a prevailing contribution of group II mGluRs over that of group III mGluRs. The mGluR1 antagonist, 7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxylate ethyl ester (CPCCOEt) prevented the full development and maintenance of HFS-LTP. By contrast, the mGluR5 antagonist, 2-methyl-6-phenylethynylpyridine (MPEP) induced LTP per se, which was impeded by CPCCOEt, and it had no effect on LTP once induced by HFS. The PPF analysis showed an enhancement of glutamate release during MPEP potentiation. The group I mGluR agonist, (R,S)-3,5-dihydroxyphenylglycine (DHPG) induced LTP per se, which was blocked by CPCCOEt. By contrast the mGluR5 agonist, (R,S)-2-chloro-5-hydroxypheylglycine (CHPG) prevented LTP elicited by HFS and DHPG as well. In conclusion vestibular LTP is inhibited by group II and III mGluRs during the early induction phase while it is facilitated by mGluR1 for achieving its full expression and consolidation. An additional inhibitory control is exerted by mGluR5 at the level of this facilitatory phase. PMID:12231639

Different metabotropic glutamate receptors play opposite roles in synaptic plasticity of the rat medial vestibular nuclei.

PubMed

Grassi, Silvarosa; Frondaroli, Adele; Pettorossi, Vito Enrico

2002-09-15

In the medial vestibular nuclei (MVN) of rat brainstem slices, the role of group II and III metabotropic glutamate receptors (mGluRs) and of the subtypes of group I mGluRs: mGluR1, mGluR5, was investigated in basal synaptic transmission and in the induction and maintenance of long-term potentiation (LTP). We used selective antagonists and agonists for mGluRs and we analysed the field potentials evoked by vestibular afferent stimulation before and after high-frequency stimulation (HFS) to induce LTP. The group II and III mGluR antagonist, (R,S)-alpha-2-methyl-4sulphonophenylglycine (MSPG), induced LTP per se and caused a reduction of the paired-pulse facilitation (PPF) ratio indicating an enhancement of glutamate release. This suggests that group II and III mGluRs are activated under basal conditions to limit glutamate release. Both the group II and III mGluR selective antagonists, 2S-2-amino-2-(1S,2S-2-carboxycycloprop-1-yl)-3-(xanth-9-yl)propanoate (LY341495) and (R,S)-alpha-methylserine-O-phosphate (MSOP), induced LTP, and the selective agonists, (2R,4R)-4-aminopyrrolidine-2,4-dicarboxylate (APDC) and L(+)-2-amino-4-phosphonobutyric acid (L-AP4) depressed the field potentials and prevented HFS-LTP, with a prevailing contribution of group II mGluRs over that of group III mGluRs. The mGluR1 antagonist, 7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxylate ethyl ester (CPCCOEt) prevented the full development and maintenance of HFS-LTP. By contrast, the mGluR5 antagonist, 2-methyl-6-phenylethynylpyridine (MPEP) induced LTP per se, which was impeded by CPCCOEt, and it had no effect on LTP once induced by HFS. The PPF analysis showed an enhancement of glutamate release during MPEP potentiation. The group I mGluR agonist, (R,S)-3,5-dihydroxyphenylglycine (DHPG) induced LTP per se, which was blocked by CPCCOEt. By contrast the mGluR5 agonist, (R,S)-2-chloro-5-hydroxypheylglycine (CHPG) prevented LTP elicited by HFS and DHPG as well. In conclusion vestibular LTP is inhibited by group II and III mGluRs during the early induction phase while it is facilitated by mGluR1 for achieving its full expression and consolidation. An additional inhibitory control is exerted by mGluR5 at the level of this facilitatory phase.

Mutation spectrum and differential gene expression in cystic and solid vestibular schwannoma.

PubMed

Zhang, Zhihua; Wang, Zhaoyan; Sun, Lianhua; Li, Xiaohua; Huang, Qi; Yang, Tao; Wu, Hao

2014-03-01

We sought to characterize the mutation spectrum of NF2 and the differential gene expression in cystic and solid vestibular schwannomas. We collected tumor tissue and blood samples of 31 cystic vestibular schwannomas and 114 solid vestibular schwannomas. Mutation screening of NF2 was performed in both tumor and blood DNA samples of all patients. cDNA microarray was used to analyze the differential gene expression between 11 cystic vestibular schwannomas and 6 solid vestibular schwannomas. Expression levels of top candidate genes were verified by quantitative reverse transcription PCR. NF2 mutations were identified in 34.5% of sporadic vestibular schwannomas, with all mutations being exclusively somatic. No significant difference was found between the mutation detection rates of cystic vestibular schwannoma (35.5%) and solid vestibular schwannoma (34.2%). cDNA microarray analysis detected a total of 46 differentially expressed genes between the cystic vestibular schwannoma and solid vestibular schwannoma samples. The significantly decreased expression of four top candidate genes, C1orf130, CNTF, COL4A3, and COL4A4, was verified by quantitative reverse transcription PCR. NF2 mutations are not directly involved in the cystic formation of vestibular schwannoma. In addition, the differential gene expression of cystic vestibular schwannoma reported in our study may provide useful insights into the molecular mechanism underlying this process.

Morphological studies of the vestibular nerve

NASA Technical Reports Server (NTRS)

Bergstroem, B.

1973-01-01

The anatomy of the intratemporal part of the vestibular nerve in man, and the possible age related degenerative changes in the nerve were studied. The form and structure of the vestibular ganglion was studied with the light microscope. A numerical analysis of the vestibular nerve, and caliber spectra of the myelinated fibers in the vestibular nerve branches were studied in individuals of varying ages. It was found that the peripheral endings of the vestibular nerve form a complicated pattern inside the vestibular sensory epithelia. A detailed description of the sensory cells and their surface organelles is included.

Quality of life of individuals submitted to vestibular rehabilitation.

PubMed

Patatas, Olívia Helena Gomes; Ganança, Cristina Freitas; Ganança, Fernando Freitas

2009-01-01

Balance disorders affect social, family and professional activities. Vestibular rehabilitation can reduce the impact of these disorders on the quality of life of individuals with vertigo. to study the influence of vestibular rehabilitation on the quality of life of individuals, correlating it with gender, age, results from computerized vectoelectronystagmography and vertigo. Retrospective. Twenty-two individuals were submitted to customized vestibular rehabilitation and the Brazilian Dizziness Handicap Inventory - DHI before and after vestibular rehabilitation. Results from this questionnaire were correlated with gender, age, vestibular assessment and the presence of vertigo. all the DHI scores reduced significantly after vestibular rehabilitation. There were no differences among genders; adults and elderly patients; irritative peripheral vestibular syndromes; deficiency syndromes and normal exams; the presence or absence of vertigo. all the individuals had improvements in their quality of life after customized vestibular rehabilitation.

Developmental Profiling of Spiral Ganglion Neurons Reveals Insights into Auditory Circuit Assembly

PubMed Central

Lu, Cindy C.; Appler, Jessica M.; Houseman, E. Andres; Goodrich, Lisa V.

2011-01-01

The sense of hearing depends on the faithful transmission of sound information from the ear to the brain by spiral ganglion (SG) neurons. However, how SG neurons develop the connections and properties that underlie auditory processing is largely unknown. We catalogued gene expression in mouse SG neurons from embryonic day 12 (E12), when SG neurons first extend projections, up until postnatal day 15 (P15), after the onset of hearing. For comparison, we also analyzed the closely-related vestibular ganglion (VG). Gene ontology analysis confirmed enriched expression of genes associated with gene regulation and neurite outgrowth at early stages, with the SG and VG often expressing different members of the same gene family. At later stages, the neurons transcribe more genes related to mature function, and exhibit a dramatic increase in immune gene expression. Comparisons of the two populations revealed enhanced expression of TGFβ pathway components in SG neurons and established new markers that consistently distinguish auditory and vestibular neurons. Unexpectedly, we found that Gata3, a transcription factor commonly associated with auditory development, is also expressed in VG neurons at early stages. We therefore defined new cohorts of transcription factors and axon guidance molecules that are uniquely expressed in SG neurons and may drive auditory-specific aspects of their differentiation and wiring. We show that one of these molecules, the receptor guanylyl cyclase Npr2, is required for bifurcation of the SG central axon. Hence, our data set provides a useful resource for uncovering the molecular basis of specific auditory circuit assembly events. PMID:21795542

Influence of mobility restriction on habituation of the vestibular apparatus

NASA Technical Reports Server (NTRS)

Gorgiladze, G. I.; Kazanskaya, G. S.

1980-01-01

Test results presented indicate that 30-day hypokinesia did not affect the intensity of nystagmus: velocity of slow phase, total number of jerks, and duration of the reaction in animals were the same as before mobility restriction and did not differ from those of the control group. However, hypokinesia resulted in the disappearance of habituation of the vestibulary system to repeated angular accelerations. The known hypokinetic changes in the endocrine system were studied. It was concluded that reduction in adrenergic function may be the cause of disappearance of vestibular apparatus habituation during hypokinesia.

Cold shivering activity after unilateral destruction of the vestibular apparatus

NASA Technical Reports Server (NTRS)

Kuzmina, G. I.

1980-01-01

The bioelectric activity of muscles (flexors and extensors of the forelimbs and hindlimbs) during cold shivering after unilateral destruction of the vestibular apparatus. It was found, that unilateral delabyrinthing produces bilateral facilitation of cold shivering in the flexor extremities more pronounced on the ipsilateral side. In the extensor muscles there was an absence of bioelectric activity both before and after delabyrinthing. Enhancement of cold shivering in the flexor extremities following intervention was evidently conditioned by removal of the inhibiting effect of the vestibulary apparatus on the function of special centers.