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.

Top-down approach to vestibular compensation: translational lessons from vestibular rehabilitation

PubMed Central

Balaban, Carey D.; Hoffer, Michael E.; Gottshall, Kim R.

2012-01-01

This review examines vestibular compensation and vestibular rehabilitation from a unified translational research perspective. Laboratory studies illustrate neurobiological principles of vestibular compensation at the molecular, cellular and systems levels in animal models that inform vestibular rehabilitation practice. However, basic research has been hampered by an emphasis on ‘naturalistic’ recovery, with time after insult and drug interventions as primary dependent variables. The vestibular rehabilitation literature, on the other hand, provides information on how the degree of compensation can be shaped by specific activity regimens. The milestones of the early spontaneous static compensation mark the re-establishment of static gaze stability, which provides a common coordinate frame for the brain to interpret residual vestibular information in the context of visual, somatosensory and visceral signals that convey gravitoinertial information. Stabilization of the head orientation and the eye orientation (suppression of spontaneous nystagmus) appear to be necessary by not sufficient conditions for successful rehabilitation, and define a baseline for initiating retraining. The lessons from vestibular rehabilitation in animal models offer the possibility of shaping the recovery trajectory to identify molecular and genetic factors that can improve vestibular compensation. PMID:22981400

Visuo-vestibular interaction: predicting the position of a visual target during passive body rotation.

PubMed

Mackrous, I; Simoneau, M

2011-11-10

Following body rotation, optimal updating of the position of a memorized target is attained when retinal error is perceived and corrective saccade is performed. Thus, it appears that these processes may enable the calibration of the vestibular system by facilitating the sharing of information between both reference frames. Here, it is assessed whether having sensory information regarding body rotation in the target reference frame could enhance an individual's learning rate to predict the position of an earth-fixed target. During rotation, participants had to respond when they felt their body midline had crossed the position of the target and received knowledge of result. During practice blocks, for two groups, visual cues were displayed in the same reference frame of the target, whereas a third group relied on vestibular information (vestibular-only group) to predict the location of the target. Participants, unaware of the role of the visual cues (visual cues group), learned to predict the location of the target and spatial error decreased from 16.2 to 2.0°, reflecting a learning rate of 34.08 trials (determined from fitting a falling exponential model). In contrast, the group aware of the role of the visual cues (explicit visual cues group) showed a faster learning rate (i.e. 2.66 trials) but similar final spatial error 2.9°. For the vestibular-only group, similar accuracy was achieved (final spatial error of 2.3°), but their learning rate was much slower (i.e. 43.29 trials). Transferring to the Post-test (no visual cues and no knowledge of result) increased the spatial error of the explicit visual cues group (9.5°), but it did not change the performance of the vestibular group (1.2°). Overall, these results imply that cognition assists the brain in processing the sensory information within the target reference frame. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

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.

The neural encoding of self-generated and externally applied movement: implications for the perception of self-motion and spatial memory

PubMed Central

Cullen, Kathleen E.

2014-01-01

The vestibular system is vital for maintaining an accurate representation of self-motion. As one moves (or is moved) toward a new place in the environment, signals from the vestibular sensors are relayed to higher-order centers. It is generally assumed the vestibular system provides a veridical representation of head motion to these centers for the perception of self-motion and spatial memory. In support of this idea, evidence from lesion studies suggests that vestibular inputs are required for the directional tuning of head direction cells in the limbic system as well as neurons in areas of multimodal association cortex. However, recent investigations in monkeys and mice challenge the notion that early vestibular pathways encode an absolute representation of head motion. Instead, processing at the first central stage is inherently multimodal. This minireview highlights recent progress that has been made towards understanding how the brain processes and interprets self-motion signals encoded by the vestibular otoliths and semicircular canals during everyday life. The following interrelated questions are considered. What information is available to the higher-order centers that contribute to self-motion perception? How do we distinguish between our own self-generated movements and those of the external world? And lastly, what are the implications of differences in the processing of these active vs. passive movements for spatial memory? PMID:24454282

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.

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

NASA Technical Reports Server (NTRS)

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

2002-01-01

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

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

PubMed

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

2002-05-01

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

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

PubMed

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

2014-04-01

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

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

PubMed Central

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

2014-01-01

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

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.

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

Neural processing of gravity information

NASA Technical Reports Server (NTRS)

Schor, Robert H.

1992-01-01

The goal of this project was to use the linear acceleration capabilities of the NASA Vestibular Research Facility (VRF) at Ames Research Center to directly examine encoding of linear accelerations in the vestibular system of the cat. Most previous studies, including my own, have utilized tilt stimuli, which at very low frequencies (e.g., 'static tilt') can be considered a reasonably pure linear acceleration (e.g., 'down'); however, higher frequencies of tilt, necessary for understanding the dynamic processing of linear acceleration information, necessarily involves rotations which can stimulate the semicircular canals. The VRF, particularly the Long Linear Sled, has promise to provide controlled pure linear accelerations at a variety of stimulus frequencies, with no confounding angular motion.

Review of book vestibular crises

NASA Technical Reports Server (NTRS)

Blagoveshchenskaya, N. S.

1980-01-01

The etiology, pathogenesis, clinical practice, treatment and rehabilitation of patients with vestibular crises is discussed. Classifications for vestibular disorders are given. Information on the frequency of vestibular crises is given.

Different neural strategies for multimodal integration: comparison of two macaque monkey species.

PubMed

Sadeghi, Soroush G; Mitchell, Diana E; Cullen, Kathleen E

2009-05-01

The integration of neck proprioceptive and vestibular inputs underlies the generation of accurate postural and motor control. Recent studies have shown that central mechanisms underlying the integration of these sensory inputs differ across species. Notably, in rhesus monkey (Macaca mulata), an Old World monkey, neurons in the vestibular nuclei are insensitive to passive stimulation of neck proprioceptors. In contrast, in squirrel monkey, a New World monkey, stimulation produces robust modulation. This has led to the suggestion that there are differences in how sensory information is integrated during self-motion in Old versus New World monkeys. To test this hypothesis, we recorded from neurons in the vestibular nuclei of another species in the Macaca genus [i.e., M. fascicularis (cynomolgus monkey)]. Recordings were made from vestibular-only (VO) and position-vestibular-pause (PVP) neurons. The majority (53%) of neurons in both groups were sensitive to neck proprioceptive and vestibular stimulation during passive body-under-head and whole-body rotation, respectively. Furthermore, responses during passive rotations of the head-on-body were well predicted by the linear summation of vestibular and neck responses (which were typically antagonistic). During active head movement, the responses of VO and PVP neurons were further attenuated (relative to a model based on linear summation) for the duration of the active head movement or gaze shift, respectively. Taken together, our findings show that the brain's strategy for the central processing of sensory information can vary even within a single genus. We suggest that similar divergence may be observed in other areas in which multimodal integration occurs.

Different Neural Strategies for Multimodal Integration: Comparison of two Macaque Monkey Species

PubMed Central

Sadeghi, Soroush G.; Mitchell, Diana E.; Cullen, Kathleen E.

2012-01-01

The integration of neck proprioceptive and vestibular inputs underlies the generation of accurate postural and motor control. Recent studies have shown that central mechanisms underlying the integration of these sensory inputs differ across species. Notably, in rhesus monkey (macaca mulata), an Old World monkey, neurons in the vestibular nuclei are insensitive to passive stimulation of neck proprioceptors. In contrast, in squirrel monkey, a New World monkey, stimulation produces robust modulation. This has led to the suggestion that there are differences in how sensory information is integrated during self motion in old versus New World monkeys. To test this hypothesis, we recorded from neurons in the vestibular nuclei of another species in the macaca genus (i.e., macaca fascicularis (cynomolgus monkey)). Recordings were made from vestibular-only (VO) and position-vestibular-pause (PVP) neurons. The majority (53%) of neurons in both groups were sensitive to neck proprioceptive and vestibular stimulation during passive body-under-head and whole body rotation, respectively. Furthermore, responses during passive rotations of the head-on-body were well predicted by the linear summation of vestibular and neck responses (which were typically antagonistic). During active head movement, the responses of VO and PVP neurons were further attenuated (relative to a model based on linear summation) for the duration of the active head movement or gaze shift, respectively. Taken together, our findings show that the brain's strategy for the central processing of sensory information can vary even within a single genus. We suggest that similar divergence may be observed in other areas in which multimodal integration occurs. PMID:19283371

Neural correlates of motor learning in the vestibulo-ocular reflex: dynamic regulation of multimodal integration in the macaque vestibular system

PubMed Central

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

2010-01-01

Motor learning is required for the reacquisition of skills that have been compromised as a result of brain lesion or disease, as well as for the acquisition of new skills. Behaviors with well-characterized anatomy and physiology are required to yield significant insight into changes that occur in the brain during motor learning. The vestibulo-ocular-reflex (VOR) is well suited to establish connections between neurons, neural circuits, and motor performance during learning. Here we examined the linkage between neuronal and behavioural VOR responses in alert behaving monkeys (macaca mulatta) during the impressive recovery that occurs after unilateral vestibular loss. We show, for the first time, that motor learning is characterized by the dynamic reweighting of inputs from different modalities (i.e., vestibular versus extra-vestibular) at the level of the single neurons which constitute the first central stage of vestibular processing. Specifically, two types of information, which did not influence neuronal responses prior to the lesion, had an important role during compensation. First, unmasked neck proprioceptive inputs played a critical role in the early stages of this process demonstrated by faster and more substantial recovery of vestibular responses in proprioceptive sensitive neurons. Second, neuronal and VOR responses were significantly enhanced during active relative to passive head motion later in the compensation process (>3 weeks). Taken together, our findings provide evidence linking the dynamic regulation of multimodal integration at the level of single neurons and behavioural recovery, suggesting a role for homeostatic mechanisms in VOR motor learning. PMID:20668199

Role of somatosensory and vestibular cues in attenuating visually induced human postural sway

NASA Technical Reports Server (NTRS)

Peterka, Robert J.; Benolken, Martha S.

1993-01-01

The purpose was to determine the contribution of visual, vestibular, and somatosensory cues to the maintenance of stance in humans. Postural sway was induced by full field, sinusoidal visual surround rotations about an axis at the level of the ankle joints. The influences of vestibular and somatosensory cues were characterized by comparing postural sway in normal and bilateral vestibular absent subjects in conditions that provided either accurate or inaccurate somatosensory orientation information. In normal subjects, the amplitude of visually induced sway reached a saturation level as stimulus amplitude increased. The saturation amplitude decreased with increasing stimulus frequency. No saturation phenomena was observed in subjects with vestibular loss, implying that vestibular cues were responsible for the saturation phenomenon. For visually induced sways below the saturation level, the stimulus-response curves for both normal and vestibular loss subjects were nearly identical implying that (1) normal subjects were not using vestibular information to attenuate their visually induced sway, possibly because sway was below a vestibular-related threshold level, and (2) vestibular loss subjects did not utilize visual cues to a greater extent than normal subjects; that is, a fundamental change in visual system 'gain' was not used to compensate for a vestibular deficit. An unexpected finding was that the amplitude of body sway induced by visual surround motion could be almost three times greater than the amplitude of the visual stimulus in normals and vestibular loss subjects. This occurred in conditions where somatosensory cues were inaccurate and at low stimulus amplitudes. A control system model of visually induced postural sway was developed to explain this finding. For both subject groups, the amplitude of visually induced sway was smaller by a factor of about four in tests where somatosensory cues provided accurate versus inaccurate orientation information. This implied that (1) the vestibular loss subjects did not utilize somatosensory cues to a greater extent than normal subjects; that is, changes in somatosensory system 'gain' were not used to compensate for a vestibular deficit, and (2) the threshold for the use of vestibular cues in normals was apparently lower in test conditions where somatosensory cues were providing accurate orientation information.

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.

Dynamic reweighting of three modalities for sensor fusion.

PubMed

Hwang, Sungjae; Agada, Peter; Kiemel, Tim; Jeka, John J

2014-01-01

We simultaneously perturbed visual, vestibular and proprioceptive modalities to understand how sensory feedback is re-weighted so that overall feedback remains suited to stabilizing upright stance. Ten healthy young subjects received an 80 Hz vibratory stimulus to their bilateral Achilles tendons (stimulus turns on-off at 0.28 Hz), a ± 1 mA binaural monopolar galvanic vestibular stimulus at 0.36 Hz, and a visual stimulus at 0.2 Hz during standing. The visual stimulus was presented at different amplitudes (0.2, 0.8 deg rotation about ankle axis) to measure: the change in gain (weighting) to vision, an intramodal effect; and a change in gain to vibration and galvanic vestibular stimulation, both intermodal effects. The results showed a clear intramodal visual effect, indicating a de-emphasis on vision when the amplitude of visual stimulus increased. At the same time, an intermodal visual-proprioceptive reweighting effect was observed with the addition of vibration, which is thought to change proprioceptive inputs at the ankles, forcing the nervous system to rely more on vision and vestibular modalities. Similar intermodal effects for visual-vestibular reweighting were observed, suggesting that vestibular information is not a "fixed" reference, but is dynamically adjusted in the sensor fusion process. This is the first time, to our knowledge, that the interplay between the three primary modalities for postural control has been clearly delineated, illustrating a central process that fuses these modalities for accurate estimates of self-motion.

Multimodal integration in rostral fastigial nucleus provides an estimate of body movement

PubMed Central

Brooks, Jessica X.; Cullen, Kathleen E.

2012-01-01

The ability to accurately control posture and perceive self motion and spatial orientation requires knowledge of both the motion of the head and body. However, while the vestibular sensors and nuclei directly encode head motion, no sensors directly encode body motion. Instead, the convergence of vestibular and neck proprioceptive inputs during self-motion is generally believed to underlie the ability to compute body motion. Here, we provide evidence that the brain explicitly computes an internal estimate of body motion at the level of single cerebellar neurons. Neuronal responses were recorded from the rostral fastigial nucleus, the most medial of the deep cerebellar nuclei, during whole-body, body-under-head, and head-on-body rotations. We found that approximately half of the neurons encoded the motion of the body-in-space, while the other half encoded the motion of the head-in-space in a manner similar to neurons in the vestibular nuclei. Notably, neurons encoding body motion responded to both vestibular and proprioceptive stimulation (accordingly termed bimodal neurons). In contrast, neurons encoding head motion were only sensitive to vestibular inputs (accordingly termed unimodal neurons). Comparison of the proprioceptive and vestibular responses of bimodal neurons further revealed similar tuning in response to changes in head-on-body position. We propose that the similarity in nonlinear processing of vestibular and proprioceptive signals underlies the accurate computation of body motion. Furthermore, the same neurons that encode body motion (i.e., bimodal neurons) most likely encode vestibular signals in a body referenced coordinate frame, since the integration of proprioceptive and vestibular information is required for both computations. PMID:19710303

Role of somatosensory and vestibular cues in attenuating visually induced human postural sway

NASA Technical Reports Server (NTRS)

Peterka, R. J.; Benolken, M. S.

1995-01-01

The purpose of this study was to determine the contribution of visual, vestibular, and somatosensory cues to the maintenance of stance in humans. Postural sway was induced by full-field, sinusoidal visual surround rotations about an axis at the level of the ankle joints. The influences of vestibular and somatosensory cues were characterized by comparing postural sway in normal and bilateral vestibular absent subjects in conditions that provided either accurate or inaccurate somatosensory orientation information. In normal subjects, the amplitude of visually induced sway reached a saturation level as stimulus amplitude increased. The saturation amplitude decreased with increasing stimulus frequency. No saturation phenomena were observed in subjects with vestibular loss, implying that vestibular cues were responsible for the saturation phenomenon. For visually induced sways below the saturation level, the stimulus-response curves for both normal subjects and subjects experiencing vestibular loss were nearly identical, implying (1) that normal subjects were not using vestibular information to attenuate their visually induced sway, possibly because sway was below a vestibular-related threshold level, and (2) that subjects with vestibular loss did not utilize visual cues to a greater extent than normal subjects; that is, a fundamental change in visual system "gain" was not used to compensate for a vestibular deficit. An unexpected finding was that the amplitude of body sway induced by visual surround motion could be almost 3 times greater than the amplitude of the visual stimulus in normal subjects and subjects with vestibular loss. This occurred in conditions where somatosensory cues were inaccurate and at low stimulus amplitudes. A control system model of visually induced postural sway was developed to explain this finding. For both subject groups, the amplitude of visually induced sway was smaller by a factor of about 4 in tests where somatosensory cues provided accurate versus inaccurate orientation information. This implied (1) that the subjects experiencing vestibular loss did not utilize somatosensory cues to a greater extent than normal subjects; that is, changes in somatosensory system "gain" were not used to compensate for a vestibular deficit, and (2) that the threshold for the use of vestibular cues in normal subjects was apparently lower in test conditions where somatosensory cues were providing accurate orientation information.

Neural Correlates of Sensory Substitution in Vestibular Pathways Following Complete Vestibular Loss

PubMed Central

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

2012-01-01

Sensory substitution is the term typically used in reference to sensory prosthetic devices designed to replace input from one defective modality with input from another modality. Such devices allow an alternative encoding of sensory information that is no longer directly provided by the defective modality in a purposeful and goal-directed manner. The behavioral recovery that follows complete vestibular loss is impressive and has long been thought to take advantage of a natural form of sensory substitution in which head motion information is no longer provided by vestibular inputs, but instead by extra-vestibular inputs such as proprioceptive and motor efference copy signals. Here we examined the neuronal correlates of this behavioral recovery after complete vestibular loss in alert behaving monkeys (Macaca mulata). We show for the first time that extra-vestibular inputs substitute for the vestibular inputs to stabilize gaze at the level of single neurons in the VOR premotor circuitry. The summed weighting of neck proprioceptive and efference copy information was sufficient to explain simultaneously observed behavioral improvements in gaze stability. Furthermore, by altering correspondence between intended and actual head movement we revealed a four-fold increase in the weight of neck motor efference copy signals consistent with the enhanced behavioral recovery observed when head movements are voluntary versus unexpected. Thus, taken together our results provide direct evidence that the substitution by extra-vestibular inputs in vestibular pathways provides a neural correlate for the improvements in gaze stability that are observed following the total loss of vestibular inputs. PMID:23077054

Visual and vestibular components of motion sickness.

PubMed

Eyeson-Annan, M; Peterken, C; Brown, B; Atchison, D

1996-10-01

The relative importance of visual and vestibular information in the etiology of motion sickness (MS) is not well understood, but these factors can be manipulated by inducing Coriolis and pseudo-Coriolis effects in experimental subjects. We hypothesized that visual and vestibular information are equivalent in producing MS. The experiments reported here aim, in part, to examine the relative influence of Coriolis and pseudo-Coriolis effects in inducing MS. We induced MS symptoms by combinations of whole body rotation and tilt, and environment rotation and tilt, in 22 volunteer subjects. Subjects participated in all of the experiments with at least 2 d between each experiment to dissipate after-effects. We recorded MS signs and symptoms when only visual stimulation was applied, when only vestibular stimulation was applied, and when both visual and vestibular stimulation were applied under specific conditions of whole body and environmental tilt. Visual stimuli produced more symptoms of MS than vestibular stimuli when only visual or vestibular stimuli were used (ANOVA F = 7.94, df = 1, 21 p = 0.01), but there was no significant difference in MS production when combined visual and vestibular stimulation were used to produce the Coriolis effect or pseudo-Coriolis effect (ANOVA: F = 0.40, df = 1, 21 p = 0.53). This was further confirmed by examination of the order in which the symptoms occurred and the lack of a correlation between previous experience and visually induced MS. Visual information is more important than vestibular input in causing MS when these stimuli are presented in isolation. In conditions where both visual and vestibular information are present, cross-coupling appears to occur between the pseudo-Coriolis effect and the Coriolis effect, as these two conditions are not significantly different in producing MS symptoms.

Vision can recalibrate the vestibular reafference signal used to re-establish postural equilibrium following a platform perturbation.

PubMed

Toth, Adam J; Harris, Laurence R; Zettel, John; Bent, Leah R

2017-02-01

Visuo-vestibular recalibration, in which visual information is used to alter the interpretation of vestibular signals, has been shown to influence both oculomotor control and navigation. Here we investigate whether vision can recalibrate the vestibular feedback used during the re-establishment of equilibrium following a perturbation. The perturbation recovery responses of nine participants were examined following exposure to a period of 11 s of galvanic vestibular stimulation (GVS). During GVS in VISION trials, occlusion spectacles provided 4 s of visual information that enabled participants to correct for the GVS-induced tilt and associate this asymmetric vestibular signal with a visually provided 'upright'. NoVISION trials had no such visual experience. Participants used the visual information to assist in realigning their posture compared to when visual information was not provided (p < 0.01). The initial recovery response to a platform perturbation was not impacted by whether vision had been provided during the preceding GVS, as determined by peak centre of mass and pressure deviations (p = 0.09). However, after using vision to reinterpret the vestibular signal during GVS, final centre of mass and pressure equilibrium positions were significantly shifted compared to trials in which vision was not available (p < 0.01). These findings support previous work identifying a prominent role of vestibular input for re-establishing postural equilibrium following a perturbation. Our work is the first to highlight the capacity for visual feedback to recalibrate the vertical interpretation of vestibular reafference for re-establishing equilibrium following a perturbation. This demonstrates the rapid adaptability of the vestibular reafference signal for postural control.

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.

Velocity dependence of vestibular information for postural control on tilting surfaces

PubMed Central

Kluzik, JoAnn; Hlavacka, Frantisek

2016-01-01

Vestibular information is known to be important for postural stability on tilting surfaces, but the relative importance of vestibular information across a wide range of surface tilt velocities is less clear. We compared how tilt velocity influences postural orientation and stability in nine subjects with bilateral vestibular loss and nine age-matched, control subjects. Subjects stood on a force platform that tilted 6 deg, toes-up at eight velocities (0.25 to 32 deg/s), with and without vision. Results showed that visual information effectively compensated for lack of vestibular information at all tilt velocities. However, with eyes closed, subjects with vestibular loss were most unstable within a critical tilt velocity range of 2 to 8 deg/s. Subjects with vestibular deficiency lost their balance in more than 90% of trials during the 4 deg/s condition, but never fell during slower tilts (0.25–1 deg/s) and fell only very rarely during faster tilts (16–32 deg/s). At the critical velocity range in which falls occurred, the body center of mass stayed aligned with respect to the surface, onset of ankle dorsiflexion was delayed, and there was delayed or absent gastrocnemius inhibition, suggesting that subjects were attempting to actively align their upper bodies with respect to the moving surface instead of to gravity. Vestibular information may be critical for stability at velocities of 2 to 8 deg/s because postural sway above 2 deg/s may be too fast to elicit stabilizing responses through the graviceptive somatosensory system, and postural sway below 8 deg/s may be too slow for somatosensory-triggered responses or passive stabilization from trunk inertia. PMID:27486101

Information transmission and detection thresholds in the vestibular nuclei: single neurons vs. population encoding

PubMed Central

Massot, Corentin; Chacron, Maurice J.

2011-01-01

Understanding how sensory neurons transmit information about relevant stimuli remains a major goal in neuroscience. Of particular relevance are the roles of neural variability and spike timing in neural coding. Peripheral vestibular afferents display differential variability that is correlated with the importance of spike timing; regular afferents display little variability and use a timing code to transmit information about sensory input. Irregular afferents, conversely, display greater variability and instead use a rate code. We studied how central neurons within the vestibular nuclei integrate information from both afferent classes by recording from a group of neurons termed vestibular only (VO) that are known to make contributions to vestibulospinal reflexes and project to higher-order centers. We found that, although individual central neurons had sensitivities that were greater than or equal to those of individual afferents, they transmitted less information. In addition, their velocity detection thresholds were significantly greater than those of individual afferents. This is because VO neurons display greater variability, which is detrimental to information transmission and signal detection. Combining activities from multiple VO neurons increased information transmission. However, the information rates were still much lower than those of equivalent afferent populations. Furthermore, combining responses from multiple VO neurons led to lower velocity detection threshold values approaching those measured from behavior (∼2.5 vs. 0.5–1°/s). Our results suggest that the detailed time course of vestibular stimuli encoded by afferents is not transmitted by VO neurons. Instead, they suggest that higher vestibular pathways must integrate information from central vestibular neuron populations to give rise to behaviorally observed detection thresholds. PMID:21307329

The vestibular system: a spatial reference for bodily self-consciousness

PubMed Central

Pfeiffer, Christian; Serino, Andrea; Blanke, Olaf

2014-01-01

Self-consciousness is the remarkable human experience of being a subject: the “I”. Self-consciousness is typically bound to a body, and particularly to the spatial dimensions of the body, as well as to its location and displacement in the gravitational field. Because the vestibular system encodes head position and movement in three-dimensional space, vestibular cortical processing likely contributes to spatial aspects of bodily self-consciousness. We review here recent data showing vestibular effects on first-person perspective (the feeling from where “I” experience the world) and self-location (the feeling where “I” am located in space). We compare these findings to data showing vestibular effects on mental spatial transformation, self-motion perception, and body representation showing vestibular contributions to various spatial representations of the body with respect to the external world. Finally, we discuss the role for four posterior brain regions that process vestibular and other multisensory signals to encode spatial aspects of bodily self-consciousness: temporoparietal junction, parietoinsular vestibular cortex, ventral intraparietal region, and medial superior temporal region. We propose that vestibular processing in these cortical regions is critical in linking multisensory signals from the body (personal and peripersonal space) with external (extrapersonal) space. Therefore, the vestibular system plays a critical role for neural representations of spatial aspects of bodily self-consciousness. PMID:24860446

Processing of angular motion and gravity information through an internal model.

PubMed

Laurens, Jean; Straumann, Dominik; Hess, Bernhard J M

2010-09-01

The vestibular organs in the base of the skull provide important information about head orientation and motion in space. Previous studies have suggested that both angular velocity information from the semicircular canals and information about head orientation and translation from the otolith organs are centrally processed in an internal model of head motion, using the principles of optimal estimation. This concept has been successfully applied to model behavioral responses to classical vestibular motion paradigms. This study measured the dynamic of the vestibuloocular reflex during postrotatory tilt, tilt during the optokinetic afternystagmus, and off-vertical axis rotation. The influence of otolith signal on the VOR was systematically varied by using a series of tilt angles. We found that the time constants of responses varied almost identically as a function of gravity in these paradigms. We show that Bayesian modeling could predict the experimental results in an accurate and consistent manner. In contrast to other approaches, the Bayesian model also provides a plausible explanation of why these vestibulooculo motor responses occur as a consequence of an internal process of optimal motion estimation.

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.

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.

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.

Vestibular blueprint in early vertebrates.

PubMed

Straka, Hans; Baker, Robert

2013-11-19

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

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.

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.

Neural correlates of hemispheric dominance and ipsilaterality within the vestibular system.

PubMed

Janzen, J; Schlindwein, P; Bense, S; Bauermann, T; Vucurevic, G; Stoeter, P; Dieterich, M

2008-10-01

Earlier functional imaging studies on the processing of vestibular information mainly focused on cortical activations due to stimulation of the horizontal semicircular canals in right-handers. Two factors were found to determine its processing in the temporo-parietal cortex: a dominance of the non-dominant hemisphere and an ipsilaterality of the neural pathways. In an investigation of the role of these factors in the vestibular otoliths, we used vestibular evoked myogenic potentials (VEMPs) in a fMRI study of monaural saccular-otolith stimulation. Our aim was to (1) analyze the hemispheric dominance for saccular-otolith information in healthy left-handers, (2) determine if there is a predominance of the ipsilateral saccular-otolith projection, and (3) evaluate the impact of both factors on the temporo-parieto-insular activation pattern. A block design with three stimulation and rest conditions was applied: (1) 102 dB-VEMP stimulation; (2) 65 dB-control-acoustic stimulation, (3) 102 dB-white-noise-control stimulation. After subtraction of acoustic side effects, bilateral activations were found in the posterior insula, the superior/middle/transverse temporal gyri, and the inferior parietal lobule. The distribution of the saccular-otolith activations was influenced by the two factors but with topographic disparity: whereas the inferior parts of the temporo-parietal cortex were mainly influenced by the ipsilaterality of the pathways, the upper parts reflected the dominance of the non-dominant hemisphere. This is in contrast to the processing of acoustic stimulation, which showed a predominance of the contralateral pathways. Our study proves the importance of the hemispheric preponderance also in left-handers, which is of relevance in the superior parts of the insula gyrus V, the inferior parietal lobule, and the superior temporal gyri.

Asymmetrical perception of body rotation after unilateral injury to human vestibular cortex.

PubMed

Philbeck, John W; Behrmann, Marlene; Biega, Tim; Levy, Lucien

2006-01-01

Vestibular information plays a key role in many perceptual and cognitive functions, but surprisingly little is known about how vestibular signals are processed at the cortical level in humans. To address this issue, we tested the ability of two patients, with damage to key components of the vestibular network in either the left or right hemisphere, to perceive passive whole-body rotations (25-125 degrees) about the yaw axis. In both patients, the posterior insula, hippocampus, putamen, and thalamus were extensively damaged. The patients' responses were compared with those of nine age- and sex-matched neurologically intact participants. The body rotations were conducted without vision and the peak angular velocities ranged from 40 degrees to 90 degrees per second. Perceived rotation was assessed by open-loop manual pointing. The right hemisphere patient exhibited poor sensitivity for body rotations toward the contralesional (left) hemispace and generally underestimated the rotations. By contrast, his judgments of rotations toward the ipsilesional (right) hemispace greatly overestimated the physical rotation by 50-70 degrees for all tested magnitudes. The left hemisphere patient's responses were more appropriately scaled for both rotation directions, falling in the low-normal range. These findings suggest that there is some degree of hemispheric specialization in the cortical processing of dynamic head rotations in the yaw plane. In this view, right hemisphere structures play a dominant role, processing rotations in both directions, while left hemisphere structures process rotations only toward the contralesional hemispace.

Task-dependent vestibular feedback responses in reaching.

PubMed

Keyser, Johannes; Medendorp, W Pieter; Selen, Luc P J

2017-07-01

When reaching for an earth-fixed object during self-rotation, the motor system should appropriately integrate vestibular signals and sensory predictions to compensate for the intervening motion and its induced inertial forces. While it is well established that this integration occurs rapidly, it is unknown whether vestibular feedback is specifically processed dependent on the behavioral goal. Here, we studied whether vestibular signals evoke fixed responses with the aim to preserve the hand trajectory in space or are processed more flexibly, correcting trajectories only in task-relevant spatial dimensions. We used galvanic vestibular stimulation to perturb reaching movements toward a narrow or a wide target. Results show that the same vestibular stimulation led to smaller trajectory corrections to the wide than the narrow target. We interpret this reduced compensation as a task-dependent modulation of vestibular feedback responses, tuned to minimally intervene with the task-irrelevant dimension of the reach. These task-dependent vestibular feedback corrections are in accordance with a central prediction of optimal feedback control theory and mirror the sophistication seen in feedback responses to mechanical and visual perturbations of the upper limb. NEW & NOTEWORTHY Correcting limb movements for external perturbations is a hallmark of flexible sensorimotor behavior. While visual and mechanical perturbations are corrected in a task-dependent manner, it is unclear whether a vestibular perturbation, naturally arising when the body moves, is selectively processed in reach control. We show, using galvanic vestibular stimulation, that reach corrections to vestibular perturbations are task dependent, consistent with a prediction of optimal feedback control theory. Copyright © 2017 the American Physiological Society.

The clinical manifestations of vestibular migraine: A review.

PubMed

O'Connell Ferster, Ashley P; Priesol, Adrian J; Isildak, Huseyin

2017-06-01

To provide an overview of vestibular migraines presentation, pathology, and diagnosis, as well as an update on current diagnostic criteria. A review of the most recent literature on vestibular migraines was performed. Vestibular migraine is a process with significant impact on the quality of life for those afflicted with the disease, with attacks of spontaneous or positional vertigo and migraine symptoms lasting several minutes to 72h. Inner ear disease can co-exist with migraine and the vestibular symptoms occurring with vestibular migraine can mimic inner ear disorders providing a challenge for clinicians in establishing diagnosis. Recent diagnostic criteria for vestibular migraine proposed by a joint committee of the Bárány Society and the International Headache Society provide an important standard for clinical diagnosis and research endeavor. Vestibular migraine is a challenging disease process to both diagnose and treat. Proper diagnosis and treatment requires a thorough understanding of the current literature. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

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;

The Role of Visual and Nonvisual Information in the Control of Locomotion

ERIC Educational Resources Information Center

Wilkie, Richard M.; Wann, John P.

2005-01-01

During locomotion, retinal flow, gaze angle, and vestibular information can contribute to one's perception of self-motion. Their respective roles were investigated during active steering: Retinal flow and gaze angle were biased by altering the visual information during computer-simulated locomotion, and vestibular information was controlled…

Modulation of Memory by Vestibular Lesions and Galvanic Vestibular Stimulation

PubMed Central

Smith, Paul F.; Geddes, Lisa H.; Baek, Jean-Ha; Darlington, Cynthia L.; Zheng, Yiwen

2010-01-01

For decades it has been speculated that there is a close association between the vestibular system and spatial memories constructed by areas of the brain such as the hippocampus. While many animal studies have been conducted which support this relationship, only in the last 10 years have detailed quantitative studies been carried out in patients with vestibular disorders. The majority of these studies suggest that complete bilateral vestibular loss results in spatial memory deficits that are not simply due to vestibular reflex dysfunction, while the effects of unilateral vestibular damage are more complex and subtle. Very recently, reports have emerged that sub-threshold, noisy galvanic vestibular stimulation can enhance memory in humans, although this has not been investigated for spatial memory as yet. These studies add to the increasing evidence that suggests a connection between vestibular sensory information and memory in humans. PMID:21173897

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

Choline acetyltransferase immunoreactivity in the human vestibular end-organs.

PubMed

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

1994-10-01

Acetylcholine (ACh) is believed to play a major role in the efferent vestibular system in several animal models, however no information regarding the role of ACh in the human efferent vestibular system has been published. Post-embedding immunohistochemistry in a hydrophilic resin was used to investigate the choline acetyltransferase immunoreactivity (ChATi) and acetylcholinesterase (AChE) histochemistry in human vestibular end-organs. ChATi and AChE activity was found in numerous bouton-type terminals at the basal area of the vestibular hair cells. These terminals were found to contact type II vestibular hair cells and the afferent chalices surrounding type I hair cells. This study provides the first evidence that the human efferent vestibular axons and terminals are cholinergic.

Adaptation to vestibular disorientation. X, Modification of vestibular nystagmus and "vertigo" by means of visual stimulation.

DOT National Transportation Integrated Search

1968-10-01

A conflict among sensory signals frequently underlies problems of disorientation, vertigo, and motion sickness. In this study, visual information in conflict with vestibular signals was presented to groups of subjects by illuminating the test room fo...

A brief review of the clinical anatomy of the vestibular-ocular connections-how much do we know?

PubMed

Bronstein, A M; Patel, M; Arshad, Q

2015-02-01

The basic connectivity from the vestibular labyrinth to the eye muscles (vestibular ocular reflex, VOR) has been elucidated in the past decade, and we summarise this in graphic format. We also review the concept of 'velocity storage', a brainstem integrator that prolongs vestibular responses. Finally, we present new discoveries of how complex visual stimuli, such as binocular rivalry, influence VOR processing. In contrast to the basic brainstem circuits, cortical vestibular circuits are far from being understood, but parietal-vestibular nuclei projections are likely to be involved.

Auditory and Vestibular Issues Related to Human Spaceflight

NASA Technical Reports Server (NTRS)

Danielson, Richard W.; Wood, Scott J.

2009-01-01

Human spaceflight provides unique opportunities to study human vestibular and auditory systems. This session will discuss 1) vestibular adaptive processes reflected by pronounced perceptual and motor coordination problems during, and after, space missions; 2) vestibular diagnostic and rehabilitative techniques (used to promote recovery after living in altered gravity environments) that may be relevant to treatment of vestibular disorders on earth; and 3) unique acoustical challenges to hearing loss prevention and crew performance during spaceflight missions.

Vestibular signals in the parasolitary nucleus.

PubMed

Barmack, N H; Yakhnitsa, V

2000-06-01

Vestibular primary afferents project to secondary vestibular neurons located in the vestibular complex. Vestibular primary afferents also project to the uvula-nodulus of the cerebellum where they terminate on granule cells. In this report we describe the physiological properties of neurons in a "new" vestibular nucleus, the parasolitary nucleus (Psol). This nucleus consists of 2,300 GABAergic neurons that project onto the ipsilateral inferior olive (beta-nucleus and dorsomedial cell column) as well as the nucleus reticularis gigantocellularis. These olivary neurons are the exclusive source of vestibularly modulated climbing fiber inputs to the cerebellum. We recorded the activity of Psol neurons during natural vestibular stimulation in anesthetized rabbits. The rabbits were placed in a three-axis rate table at the center of a large sphere, permitting vestibular and optokinetic stimulation. We recorded from 74 neurons in the Psol and from 23 neurons in the regions bordering Psol. The activity of 72/74 Psol neurons and 4/23 non-Psol neurons was modulated by vestibular stimulation in either the pitch or roll planes but not the horizontal plane. Psol neurons responded in phase with ipsilateral side-down head position or velocity during sinusoidal stimulation. Approximately 80% of the recorded Psol neurons responded to static roll-tilt. The optimal response planes of evoked vestibular responses were inferred from measurement of null planes. Optimal response planes usually were aligned with the anatomical orientation of one of the two ipsilateral vertical semicircular canals. The frequency dependence of null plane measurements indicated a convergence of vestibular information from otoliths and semicircular canals. None of the recorded neurons evinced optokinetic sensitivity. These results are consistent with the view that Psol neurons provide the vestibular signals to the inferior olive that eventually reached the cerebellum in the form of modulated climbing fiber discharges. These signals provide information about spatial orientation about the longitudinal axis.

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

NASA Technical Reports Server (NTRS)

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

2003-01-01

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

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.

The Vestibular System Implements a Linear–Nonlinear Transformation In Order to Encode Self-Motion

PubMed Central

Massot, Corentin; Schneider, Adam D.; Chacron, Maurice J.; Cullen, Kathleen E.

2012-01-01

Although it is well established that the neural code representing the world changes at each stage of a sensory pathway, the transformations that mediate these changes are not well understood. Here we show that self-motion (i.e. vestibular) sensory information encoded by VIIIth nerve afferents is integrated nonlinearly by post-synaptic central vestibular neurons. This response nonlinearity was characterized by a strong (∼50%) attenuation in neuronal sensitivity to low frequency stimuli when presented concurrently with high frequency stimuli. Using computational methods, we further demonstrate that a static boosting nonlinearity in the input-output relationship of central vestibular neurons accounts for this unexpected result. Specifically, when low and high frequency stimuli are presented concurrently, this boosting nonlinearity causes an intensity-dependent bias in the output firing rate, thereby attenuating neuronal sensitivities. We suggest that nonlinear integration of afferent input extends the coding range of central vestibular neurons and enables them to better extract the high frequency features of self-motion when embedded with low frequency motion during natural movements. These findings challenge the traditional notion that the vestibular system uses a linear rate code to transmit information and have important consequences for understanding how the representation of sensory information changes across sensory pathways. PMID:22911113

Vestibular Activation Differentially Modulates Human Early Visual Cortex and V5/MT Excitability and Response Entropy

PubMed Central

Guzman-Lopez, Jessica; Arshad, Qadeer; Schultz, Simon R; Walsh, Vincent; Yousif, Nada

2013-01-01

Head movement imposes the additional burdens on the visual system of maintaining visual acuity and determining the origin of retinal image motion (i.e., self-motion vs. object-motion). Although maintaining visual acuity during self-motion is effected by minimizing retinal slip via the brainstem vestibular-ocular reflex, higher order visuovestibular mechanisms also contribute. Disambiguating self-motion versus object-motion also invokes higher order mechanisms, and a cortical visuovestibular reciprocal antagonism is propounded. Hence, one prediction is of a vestibular modulation of visual cortical excitability and indirect measures have variously suggested none, focal or global effects of activation or suppression in human visual cortex. Using transcranial magnetic stimulation-induced phosphenes to probe cortical excitability, we observed decreased V5/MT excitability versus increased early visual cortex (EVC) excitability, during vestibular activation. In order to exclude nonspecific effects (e.g., arousal) on cortical excitability, response specificity was assessed using information theory, specifically response entropy. Vestibular activation significantly modulated phosphene response entropy for V5/MT but not EVC, implying a specific vestibular effect on V5/MT responses. This is the first demonstration that vestibular activation modulates human visual cortex excitability. Furthermore, using information theory, not previously used in phosphene response analysis, we could distinguish between a specific vestibular modulation of V5/MT excitability from a nonspecific effect at EVC. PMID:22291031

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

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.

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.

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.;

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

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.

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

Behavioral State Modulates the Activity of Brainstem Sensorimotor Neurons

PubMed Central

McArthur, Kimberly L.

2011-01-01

Sensorimotor processing must be modulated according to the animal's behavioral state. A previous study demonstrated that motion responses were strongly state dependent in birds. Vestibular eye and head responses were significantly larger and more compensatory during simulated flight, and a flight-specific vestibular tail response was also characterized. In the current study, we investigated the neural substrates for these state-dependent vestibular behaviors by recording extracellularly from neurons in the vestibular nuclear complex and comparing their spontaneous activity and sensory responses during default and simulated flight states. We show that motion-sensitive neurons in the lateral vestibular nucleus are state dependent. Some neurons increased their spontaneous firing rates during flight, though their increased excitability was not reflected in higher sensory gains. However, other neurons exhibited state-dependent gating of sensory inputs, responding to rotational stimuli only during flight. These results demonstrate that vestibular processing in the brainstem is state dependent and lay the foundation for future studies to investigate the synaptic mechanisms responsible for these modifications. PMID:22090497

Neural learning rules for the vestibulo-ocular reflex

NASA Technical Reports Server (NTRS)

Raymond, J. L.; Lisberger, S. G.

1998-01-01

Mechanisms for the induction of motor learning in the vestibulo-ocular reflex (VOR) were evaluated by recording the patterns of neural activity elicited in the cerebellum by a range of stimuli that induce learning. Patterns of climbing-fiber, vestibular, and Purkinje cell simple-spike signals were examined during sinusoidal head movement paired with visual image movement at stimulus frequencies from 0.5 to 10 Hz. A comparison of simple-spike and vestibular signals contained the information required to guide learning only at low stimulus frequencies, and a comparison of climbing-fiber and simple-spike signals contained the information required to guide learning only at high stimulus frequencies. Learning could be guided by comparison of climbing-fiber and vestibular signals at all stimulus frequencies tested, but only if climbing fiber responses were compared with the vestibular signals present 100 msec earlier. Computational analysis demonstrated that this conclusion is valid even if there is a broad range of vestibular signals at the site of plasticity. Simulations also indicated that the comparison of vestibular and climbing-fiber signals across the 100 msec delay must be implemented by a subcellular "eligibility" trace rather than by neural circuits that delay the vestibular inputs to the site of plasticity. The results suggest two alternative accounts of learning in the VOR. Either there are multiple mechanisms of learning that use different combinations of neural signals to drive plasticity, or there is a single mechanism tuned to climbing-fiber activity that follows activity in vestibular pathways by approximately 100 msec.

Assessing Readability and Reliability of Online Patient Information Regarding Vestibular Schwannoma.

PubMed

Spiers, Harry; Amin, Nikul; Lakhani, Raj; Martin, Andrew J; Patel, Parag M

2017-12-01

The aim of this study is to objectively assess the quality and readability of websites related to vestibular schwannomas. Patients are increasingly seeking information on confirmed or suspected diagnoses through the Internet. Clinicians are often concerned regarding the accuracy, quality, and readability of web-based sites. Online information relating to vestibular schwannoma was searched using the three most popular search engines. The terms "acoustic neuroma" and "vestibular schwannoma" were used. The top 50 results from each site were assessed for readability using the Flesch-Kincaid Grade Level, Flesch Reading Ease Score, and the Gunning-Fog Index. Quality of website information was scored using the DISCERN tool. Of 300 search results analyzed, 58 separate appropriate websites were identified. The mean readability score using Flesch-Kincaid Grade Level was 10.27 (95% confidence interval [CI] 9.84-10.70). The mean Flesch Reading Ease Score was 48.75 (95% CI 46.57-50.92). The Gunning-Fog Index was 13.40 (95% CI 12.92-13.89). These scores equate to someone finishing secondary school/first year university student. DISCERN scores were highly variable but consistently demonstrated great variability in quality of information. Online patient information on vestibular schwannoma is highly variable in quality. Although there are a wide range of different websites easily available to patients on their condition and its treatment options, the information is written at a difficult level which may exceed the understanding level of many patients as it is written at a higher than average level of expected reading ability.

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.

Ultrastructural localization of ChAT-like immunoreactivity in the human vestibular periphery.

PubMed

Kong, W J; Hussl, B; Thumfart, W F; Schrott-Fischer, A

1998-05-01

Acetylcholine (ACh) has long been considered a neurotransmitter candidate in the efferent vestibular system of mammals. Recently, choline acetyltransferase (ChAT), the synthesizing enzyme for ACh, was immunocytochemically localized in all five end-organs of the rat vestibule (Kong et al. (1994) Hear. Res. 75, 192-200). However, there is little information in the literature concerning the cholinergic innervation in the vestibular periphery of man. In the present study the ultrastructural localization of the ChAT-like immunoreactivity in the human vestibular periphery was investigated in order to reveal the cholinergic innervation in the human vestibular end-organs. A modified method of pre-embedding immunoelectron microscopy was applied. It was found that the ChAT-like immunoreactivity was located in the bouton-type vesiculated nerve terminals in the vestibular neurosensory epithelia of man. These ChAT-like immunostained nerve terminals make synaptic contacts either with afferent chalices surrounding type I vestibular sensory hair cells, or with type II vestibular sensory hair cells. These results show that the ChAT-like immunoreactivity in the human vestibular periphery is confined to the efferent vestibular system. The ChAT-containing efferents innervate both type I hair cells and type II hair cells, making postsynaptic and presynaptic contacts, respectively. This study presents evidence that ACh is a neurotransmitter candidate in the efferent vestibular system of man.

[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.

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

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

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

PubMed Central

Brooks, Jessica X.

2014-01-01

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

A Bayesian Account of Visual-Vestibular Interactions in the Rod-and-Frame Task.

PubMed

Alberts, Bart B G T; de Brouwer, Anouk J; Selen, Luc P J; Medendorp, W Pieter

2016-01-01

Panoramic visual cues, as generated by the objects in the environment, provide the brain with important information about gravity direction. To derive an optimal, i.e., Bayesian, estimate of gravity direction, the brain must combine panoramic information with gravity information detected by the vestibular system. Here, we examined the individual sensory contributions to this estimate psychometrically. We asked human subjects to judge the orientation (clockwise or counterclockwise relative to gravity) of a briefly flashed luminous rod, presented within an oriented square frame (rod-in-frame). Vestibular contributions were manipulated by tilting the subject's head, whereas visual contributions were manipulated by changing the viewing distance of the rod and frame. Results show a cyclical modulation of the frame-induced bias in perceived verticality across a 90° range of frame orientations. The magnitude of this bias decreased significantly with larger viewing distance, as if visual reliability was reduced. Biases increased significantly when the head was tilted, as if vestibular reliability was reduced. A Bayesian optimal integration model, with distinct vertical and horizontal panoramic weights, a gain factor to allow for visual reliability changes, and ocular counterroll in response to head tilt, provided a good fit to the data. We conclude that subjects flexibly weigh visual panoramic and vestibular information based on their orientation-dependent reliability, resulting in the observed verticality biases and the associated response variabilities.

A Bayesian Account of Visual–Vestibular Interactions in the Rod-and-Frame Task

PubMed Central

de Brouwer, Anouk J.; Medendorp, W. Pieter

2016-01-01

Abstract Panoramic visual cues, as generated by the objects in the environment, provide the brain with important information about gravity direction. To derive an optimal, i.e., Bayesian, estimate of gravity direction, the brain must combine panoramic information with gravity information detected by the vestibular system. Here, we examined the individual sensory contributions to this estimate psychometrically. We asked human subjects to judge the orientation (clockwise or counterclockwise relative to gravity) of a briefly flashed luminous rod, presented within an oriented square frame (rod-in-frame). Vestibular contributions were manipulated by tilting the subject’s head, whereas visual contributions were manipulated by changing the viewing distance of the rod and frame. Results show a cyclical modulation of the frame-induced bias in perceived verticality across a 90° range of frame orientations. The magnitude of this bias decreased significantly with larger viewing distance, as if visual reliability was reduced. Biases increased significantly when the head was tilted, as if vestibular reliability was reduced. A Bayesian optimal integration model, with distinct vertical and horizontal panoramic weights, a gain factor to allow for visual reliability changes, and ocular counterroll in response to head tilt, provided a good fit to the data. We conclude that subjects flexibly weigh visual panoramic and vestibular information based on their orientation-dependent reliability, resulting in the observed verticality biases and the associated response variabilities. PMID:27844055

Internal Models, Vestibular Cognition, and Mental Imagery: Conceptual Considerations.

PubMed

Mast, Fred W; Ellis, Andrew W

2015-01-01

Vestibular cognition has recently gained attention. Despite numerous experimental and clinical demonstrations, it is not yet clear what vestibular cognition really is. For future research in vestibular cognition, adopting a computational approach will make it easier to explore the underlying mechanisms. Indeed, most modeling approaches in vestibular science include a top-down or a priori component. We review recent Bayesian optimal observer models, and discuss in detail the conceptual value of prior assumptions, likelihood and posterior estimates for research in vestibular cognition. We then consider forward models in vestibular processing, which are required in order to distinguish between sensory input that is induced by active self-motion, and sensory input that is due to passive self-motion. We suggest that forward models are used not only in the service of estimating sensory states but they can also be drawn upon in an offline mode (e.g., spatial perspective transformations), in which interaction with sensory input is not desired. A computational approach to vestibular cognition will help to discover connections across studies, and it will provide a more coherent framework for investigating vestibular cognition.

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…

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.

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.

Vestibular-somatosensory interactions: effects of passive whole-body rotation on somatosensory detection.

PubMed

Ferrè, Elisa Raffaella; Kaliuzhna, Mariia; Herbelin, Bruno; Haggard, Patrick; Blanke, Olaf

2014-01-01

Vestibular signals are strongly integrated with information from several other sensory modalities. For example, vestibular stimulation was reported to improve tactile detection. However, this improvement could reflect either a multimodal interaction or an indirect interaction driven by vestibular effects on spatial attention and orienting. Here we investigate whether natural vestibular activation induced by passive whole-body rotation influences tactile detection. In particular, we assessed the ability to detect faint tactile stimuli to the fingertips of the left and right hand during spatially congruent or incongruent rotations. We found that passive whole-body rotations significantly enhanced sensitivity to faint shocks, without affecting response bias. Critically, this enhancement of somatosensory sensitivity did not depend on the spatial congruency between the direction of rotation and the hand stimulated. Thus, our results support a multimodal interaction, likely in brain areas receiving both vestibular and somatosensory signals.

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.

Judging sound rotation when listeners and sounds rotate: Sound source localization is a multisystem process.

PubMed

Yost, William A; Zhong, Xuan; Najam, Anbar

2015-11-01

In four experiments listeners were rotated or were stationary. Sounds came from a stationary loudspeaker or rotated from loudspeaker to loudspeaker around an azimuth array. When either sounds or listeners rotate the auditory cues used for sound source localization change, but in the everyday world listeners perceive sound rotation only when sounds rotate not when listeners rotate. In the everyday world sound source locations are referenced to positions in the environment (a world-centric reference system). The auditory cues for sound source location indicate locations relative to the head (a head-centric reference system), not locations relative to the world. This paper deals with a general hypothesis that the world-centric location of sound sources requires the auditory system to have information about auditory cues used for sound source location and cues about head position. The use of visual and vestibular information in determining rotating head position in sound rotation perception was investigated. The experiments show that sound rotation perception when sources and listeners rotate was based on acoustic, visual, and, perhaps, vestibular information. The findings are consistent with the general hypotheses and suggest that sound source localization is not based just on acoustics. It is a multisystem process.

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.;

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.

Ictal EEG/fMRI study of vertiginous seizures.

PubMed

Morano, Alessandra; Carnì, Marco; Casciato, Sara; Vaudano, Anna Elisabetta; Fattouch, Jinane; Fanella, Martina; Albini, Mariarita; Basili, Luca Manfredi; Lucignani, Giulia; Scapeccia, Marco; Tomassi, Regina; Di Castro, Elisabetta; Colonnese, Claudio; Giallonardo, Anna Teresa; Di Bonaventura, Carlo

2017-03-01

Vertigo and dizziness are extremely common complaints, related to either peripheral or central nervous system disorders. Among the latter, epilepsy has to be taken into consideration: indeed, vertigo may be part of the initial aura of a focal epileptic seizure in association with other signs/symptoms, or represent the only ictal manifestation, a rare phenomenon known as "vertiginous" or "vestibular" seizure. These ictal symptoms are usually related to a discharge arising from/involving temporal or parietal areas, which are supposed to be a crucial component of the so-called "vestibular cortex". In this paper, we describe three patients suffering from drug-resistant focal epilepsy, symptomatic of malformations of cortical development or perinatal hypoxic/ischemic lesions located in the posterior regions, who presented clusters of vertiginous seizures. The high recurrence rate of such events, recorded during video-EEG monitoring sessions, offered the opportunity to perform an ictal EEG/fMRI study to identify seizure-related hemodynamic changes. The ictal EEG/fMRI revealed the main activation clusters in the temporo-parieto-occipital regions, which are widely recognized to be involved in the processing of vestibular information. Interestingly, ictal deactivation was also detected in the ipsilateral cerebellar hemisphere, suggesting the ictal involvement of cortical-subcortical structures known to be part of the vestibular integration network. Copyright © 2016 Elsevier Inc. All rights reserved.

Adaptation of orientation vectors of otolith-related central vestibular neurons to gravity.

PubMed

Eron, Julia N; Cohen, Bernard; Raphan, Theodore; Yakushin, Sergei B

2008-09-01

Behavioral experiments indicate that central pathways that process otolith-ocular and perceptual information have adaptive capabilities. Because polarization vectors of otolith afferents are directly related to the electro-mechanical properties of the hair cell bundle, it is unlikely that they change their direction of excitation. This indicates that the adaptation must take place in central pathways. Here we demonstrate for the first time that otolith polarization vectors of canal-otolith convergent neurons in the vestibular nuclei have adaptive capability. A total of 10 vestibular-only and vestibular-plus-saccade neurons were recorded extracellularly in two monkeys before and after they were in side-down positions for 2 h. The spatial characteristics of the otolith input were determined from the response vector orientation (RVO), which is the projection of the otolith polarization vector, onto the head horizontal plane. The RVOs had no specific orientation before animals were in side-down positions but moved toward the gravitational axis after the animals were tilted for extended periods. Vector reorientations varied from 0 to 109 degrees and were linearly related to the original deviation of the RVOs from gravity in the position of adaptation. Such reorientation of central polarization vectors could provide the basis for changes in perception and eye movements related to prolonged head tilts relative to gravity or in microgravity.

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.

“Cerebellar contribution to visuo-attentional alpha rhythm: insights from weightlessness”

PubMed Central

Cebolla, A. M.; Petieau, M.; Dan, B.; Balazs, L.; McIntyre, J.; Cheron, G.

2016-01-01

Human brain adaptation in weightlessness follows the necessity to reshape the dynamic integration of the neural information acquired in the new environment. This basic aspect was here studied by the electroencephalogram (EEG) dynamics where oscillatory modulations were measured during a visuo-attentional state preceding a visuo-motor docking task. Astronauts in microgravity conducted the experiment in free-floating aboard the International Space Station, before the space flight and afterwards. We observed stronger power decrease (~ERD: event related desynchronization) of the ~10 Hz oscillation from the occipital-parietal (alpha ERD) to the central areas (mu ERD). Inverse source modelling of the stronger alpha ERD revealed a shift from the posterior cingulate cortex (BA31, from the default mode network) on Earth to the precentral cortex (BA4, primary motor cortex) in weightlessness. We also observed significant contribution of the vestibular network (BA40, BA32, and BA39) and cerebellum (lobule V, VI). We suggest that due to the high demands for the continuous readjustment of an appropriate body posture in free-floating, this visuo-attentional state required more contribution from the motor cortex. The cerebellum and the vestibular network involvement in weightlessness might support the correction signals processing necessary for postural stabilization, and the increased demand to integrate incongruent vestibular information. PMID:27883068

Tetra-ataxiometric Posturography in Patients with Migrainous Vertigo.

PubMed

Ongun, Nedim; Atalay, Nilgun S; Degirmenci, Eylem; Sahin, Fusun; Bir, Levent Sinan

2016-01-01

Migraine is a common disorder characterized by headache attacks frequently accompanied by vestibular symptoms like dizziness, vertigo, and balance disorders. Clinical studies support a strong link between migraine and vertigo rather than between other headache types and vertigo or nonvertiginous dizziness. There is a lack of consensus regarding the pathophysiology of migrainous vertigo. Activation of central vestibular processing during migraine attacks and vasospasm-induced ischemia of the labyrinth are reported as the probable responsible mechanisms. Because vestibular examination alone does not provide enough information for diagnosis of migrainous vertigo, posturography systems which provide objective assessment of somatosensory, vestibular, and visual information would be very helpful to show concomitant involvement of the vestibular and somato-sensorial systems. There are few posturographic studies on patients with migraine but it seems that how balance is affected in patients with migraine and/or migrainous vertigo is still not clear. We want to investigate balance function in migraineurs with and without vertigo with a tetra-ataxiometric posturography system and our study is the first study in which tetra-ataxiometric static posturography was used to evaluate postural abnormalities in a well-defined population of patients with migrainous vertigo. To investigate balance functions in migraineurs with and without vertigo with a tetra-ataxiometric posturography system. Prospective, nonrandomized, controlled study. Pamukkale University Hospital, Neurology and Physical Therapy and Rehabilitation outpatient clinics. Sixteen patients with migrainous vertigo, 16 patients with migraine without aura and no vestibular symptoms, and 16 controls were included in the study. Computerized static posturography system was performed and statistical analyses of fall, Fourier, Stability, and Weight distribution indexes were performed. The tetra-ataxiometric posturography device measures vertical pressure fluctuations on 4 independent stable platforms, each placed beneath 2 heels and toe parts of the patient; inputs from these platforms are integrated and processed by a computer digitally. Four separate plates are used and perpendicular pressures of the anterior and posterior feet are measured. Pressure of each force plate is measured and data was analyzed by the software program. A very small, non-randomized, and controlled study with the inability to find an answer to the mechanism of involvement of the somatosensorial system and vestibular system in migrainous headaches. The distribution of patients with posturographical abnormalities in the migrainous vertigo group was significantly different than the control group. Distribution of the patients with posturographical abnormalities in the high frequencies of the head-right position was significantly different in the migrainous vertigo group than in the control group and distribution of the patients with posturographical abnormalities in high frequencies of the head-right position was significantly different in the migraine group than in the controls groups. The stability index of the migrainous vertigo group was significantly higher than in the control group when tested on in the neutral-head position with open eyes. In this first study of tetra-ataxiometric static posturography evaluating postural abnormalities in a well-defined population of patients with migrainous vertigo, the central part of the vestibular apparatus would be responsible of postural abnormalities in patients with migraine and migrainous vertigo.

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.

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

NASA Technical Reports Server (NTRS)

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

2001-01-01

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

Expression of vesicular glutamate transporters in peripheral vestibular structures and vestibular nuclear complex of rat.

PubMed

Zhang, F X; Pang, Y W; Zhang, M M; Zhang, T; Dong, Y L; Lai, C H; Shum, D K Y; Chan, Y S; Li, J L; Li, Y Q

2011-01-26

Glutamate transmission from vestibular end organs to central vestibular nuclear complex (VNC) plays important role in transferring sensory information about head position and movements. Three isoforms of vesicular glutamate transporters (VGLUTs) have been considered so far the most specific markers for glutamatergic neurons/cells. In this study, VGLUT1 and VGLUT2 were immunohistochemically localized to axon terminals in VNC and somata of vestibular primary afferents in association with their central and peripheral axon endings, and VGLUT1 and VGLUT3 were co-localized to hair cells of otolith maculae and cristae ampullaris. VGLUT1 and VGLUT2 defined three subsets of Scarpa's neurons (vestibular ganglionic neurons): those co-expressing VGLUT1 and VGLUT2 or expressing only VGLUT2, and those expressing neither. In addition, many neurons located in all vestibular subnuclei were observed to contain hybridized signals for VGLUT2 mRNA and a few VNC neurons, mostly scattered in medial vestibular nucleus (MVe), displayed VGLUT1 mRNA labelling. Following unilateral ganglionectomy, asymmetries of VGLUT1-immunoreactivity (ir) and VGLUT2-ir occurred between two VNCs, indicating that the VNC terminals containing VGLUT1 and/or VGLUT2 are partly of peripheral origin. The present data indicate that the constituent cells/neurons along the vestibular pathway selectively apply VGLUT isoforms to transport glutamate into synaptic vesicles for glutamate transmission. © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

Multimodal Integration of Self-Motion Cues in the Vestibular System: Active versus Passive Translations

PubMed Central

Carriot, Jerome; Brooks, Jessica X.

2013-01-01

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

Alcohol and disorientation-related responses. II, Nystagmus and "vertigo" during angular acceleration.

DOT National Transportation Integrated Search

1971-04-01

The integrity of the visual and vestibular systems is important in the maintenance of orientation during flight. Although alcohol is known to affect the vestibular system through the development of a positional alcohol nystagmus, information concerni...

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

Properties of cerebellar fastigial neurons during translation, rotation, and eye movements

NASA Technical Reports Server (NTRS)

Shaikh, Aasef G.; Ghasia, Fatema F.; Dickman, J. David; Angelaki, Dora E.

2005-01-01

The most medial of the deep cerebellar nuclei, the fastigial nucleus (FN), receives sensory vestibular information and direct inhibition from the cerebellar vermis. We investigated the signal processing in the primate FN by recording single-unit activities during translational motion, rotational motion, and eye movements. Firing rate modulation during horizontal plane translation in the absence of eye movements was observed in all non-eye-movement-sensitive cells and 26% of the pursuit eye-movement-sensitive neurons in the caudal FN. Many non-eye-movement-sensitive cells recorded in the rostral FN of three fascicularis monkeys exhibited convergence of signals from both the otolith organs and the semicircular canals. At low frequencies of translation, the majority of these rostral FN cells changed their firing rates in phase with head velocity rather than linear acceleration. As frequency increased, FN vestibular neurons exhibited a wide range of response dynamics with most cells being characterized by increasing phase leads as a function of frequency. Unlike cells in the vestibular nuclei, none of the rostral FN cells responded to rotational motion alone, without simultaneously exhibiting sensitivity to translational motion. Modulation during earth-horizontal axis rotation was observed in more than half (77%) of the neurons, although with smaller gains than during translation. In contrast, only 47% of the cells changed their firing rates during earth-vertical axis rotations in the absence of a dynamic linear acceleration stimulus. These response properties suggest that the rostral FN represents a main processing center of otolith-driven information for inertial motion detection and spatial orientation.

Adaptation of vestibular signals for self-motion perception

PubMed Central

St George, Rebecca J; Day, Brian L; Fitzpatrick, Richard C

2011-01-01

A fundamental concern of the brain is to establish the spatial relationship between self and the world to allow purposeful action. Response adaptation to unvarying sensory stimuli is a common feature of neural processing, both peripherally and centrally. For the semicircular canals, peripheral adaptation of the canal-cupula system to constant angular-velocity stimuli dominates the picture and masks central adaptation. Here we ask whether galvanic vestibular stimulation circumvents peripheral adaptation and, if so, does it reveal central adaptive processes. Transmastoidal bipolar galvanic stimulation and platform rotation (20 deg s−1) were applied separately and held constant for 2 min while perceived rotation was measured by verbal report. During real rotation, the perception of turn decayed from the onset of constant velocity with a mean time constant of 15.8 s. During galvanic-evoked virtual rotation, the perception of rotation initially rose but then declined towards zero over a period of ∼100 s. For both stimuli, oppositely directed perceptions of similar amplitude were reported when stimulation ceased indicating signal adaptation at some level. From these data the time constants of three independent processes were estimated: (i) the peripheral canal-cupula adaptation with time constant 7.3 s, (ii) the central ‘velocity-storage’ process that extends the afferent signal with time constant 7.7 s, and (iii) a long-term adaptation with time constant 75.9 s. The first two agree with previous data based on constant-velocity stimuli. The third component decayed with the profile of a real constant angular acceleration stimulus, showing that the galvanic stimulus signal bypasses the peripheral transformation so that the brainstem sees the galvanic signal as angular acceleration. An adaptive process involving both peripheral and central processes is indicated. Signals evoked by most natural movements will decay peripherally before adaptation can exert an appreciable effect, making a specific vestibular behavioural role unlikely. This adaptation appears to be a general property of the internal coding of self-motion that receives information from multiple sensory sources and filters out the unvarying components regardless of their origin. In this instance of a pure vestibular sensation, it defines the afferent signal that represents the stationary or zero-rotation state. PMID:20937715

Understanding the pusher behavior of some stroke patients with spatial deficits: a pilot study.

PubMed

Pérennou, Dominic Alain; Amblard, Bernard; Laassel, El Mostafa; Benaim, Charles; Hérisson, Christian; Pélissier, Jacques

2002-04-01

To investigate whether pusher behavior (ie, a tendency among stroke patients with spatial deficits to actively push away from the nonparalyzed side and to resist any attempt to hold a more upright posture) affects only the trunk, for which gravitational feedback is given by somesthetic information, or the head as well, whose gravitational information is mainly given by the vestibular system (without vision). Description and measurement of clinical features. Rehabilitation center research laboratory. Eight healthy subjects age matched to 14 patients with left hemiplegia resulting from right-hemisphere stroke (3 pushers showing a severe spatial neglect, 11 without pusher behavior). All participants were asked to actively maintain an erect posture while sitting for 8 seconds on a rocking, laterally unstable platform. The task was performed with (in light) and without (in darkness) vision. The number of trials needed to succeed in the task was monitored. In successful trials, head, shoulders, thoracolumbar spine, and pelvis orientation in roll were measured by means of an automated, optical television image processor. Compared with other patients and healthy subjects, the 3 pushers missed many more trials and displayed a contralesional tilt of the pelvis but kept a correct head orientation. This tilt was especially pronounced without vision. Spatial neglect was a key factor, explaining 56% of patients' misorientation behavior with vision and 61% without vision. This pilot kinematic analysis shows that pusher behavior does not result from disrupted processing of vestibular information (eg, caused by a lesion involving the vestibular cortex); rather, it results from a high-order disruption in the processing of somesthetic information originating in the left hemibody, which could be graviceptive neglect (extinction). This disruption leads pushers to actively adjust their body posture to a subjective vertical biased to the side opposite the cerebral lesion. Copyright 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

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.

Adaptation to vestibular disorientation. IV, Responses to angular acceleration and to bilateral caloric stimulation following unilateral caloric habituation.

DOT National Transportation Integrated Search

1967-01-01

The paper provides information that angular acceleration tests of the vestibular system transcend clinical caloric tests in revealing adaptation to angular accelerations as experienced in rotary motions, including flight situations. The caloric test ...

The Increased Sensitivity of Irregular Peripheral Canal and Otolith Vestibular Afferents Optimizes their Encoding of Natural Stimuli

PubMed Central

Schneider, Adam D.; Jamali, Mohsen; Carriot, Jerome; Chacron, Maurice J.

2015-01-01

Efficient processing of incoming sensory input is essential for an organism's survival. A growing body of evidence suggests that sensory systems have developed coding strategies that are constrained by the statistics of the natural environment. Consequently, it is necessary to first characterize neural responses to natural stimuli to uncover the coding strategies used by a given sensory system. Here we report for the first time the statistics of vestibular rotational and translational stimuli experienced by rhesus monkeys during natural (e.g., walking, grooming) behaviors. We find that these stimuli can reach intensities as high as 1500 deg/s and 8 G. Recordings from afferents during naturalistic rotational and linear motion further revealed strongly nonlinear responses in the form of rectification and saturation, which could not be accurately predicted by traditional linear models of vestibular processing. Accordingly, we used linear–nonlinear cascade models and found that these could accurately predict responses to naturalistic stimuli. Finally, we tested whether the statistics of natural vestibular signals constrain the neural coding strategies used by peripheral afferents. We found that both irregular otolith and semicircular canal afferents, because of their higher sensitivities, were more optimized for processing natural vestibular stimuli as compared with their regular counterparts. Our results therefore provide the first evidence supporting the hypothesis that the neural coding strategies used by the vestibular system are matched to the statistics of natural stimuli. PMID:25855169

Failure of gamma-aminobutyrate acid-beta agonist baclofen to improve balance, gait, and postural control after vestibular schwannoma resection.

PubMed

De Valck, Claudia F J; Vereeck, Luc; Wuyts, Floris L; Van de Heyning, Paul H

2009-04-01

Incomplete postural control often occurs after vestibular schwannoma (VS) surgery. Customized vestibular rehabilitation in man improves and speeds up this process. Animal experiments have shown an improved and faster vestibular compensation after administration of the gamma-aminobutyrate acid (GABA)-beta agonist baclofen. To examine whether medical treatment with baclofen provides an improvement of the compensation process after VS surgery. A time-series study with historical control. Tertiary referral center. Thirteen patients who underwent VS resection were included and compared with a matched group of patients. In addition to an individualized vestibular rehabilitation protocol, the study group received medical treatment with 30 mg baclofen (a GABA-beta agonist) daily during the first 6 weeks after surgery. Clinical gait and balance tests (Romberg maneuver, standing on foam, tandem Romberg, single-leg stance, Timed Up & Go test, tandem gait, Dynamic Gait Index) and Dizziness Handicap Inventory. Follow-up until 24 weeks after surgery. When examining the postoperative test results, the group treated with baclofen did not perform better when compared with the matched (historical control) group. Repeated-measures analysis of variance revealed no significant group effect, but a significant time effect for almost all balance tests during the acute recovery period was found. An interaction effect between time and intervention was seen concerning single-leg stance and Dizziness Handicap Inventory scores for the acute recovery period. Medical therapy with baclofen did not seem to be beneficial in the process of central vestibular compensation.

Effects of aging on whole body and segmental control while obstacle crossing under impaired sensory conditions.

PubMed

Novak, Alison C; Deshpande, Nandini

2014-06-01

The ability to safely negotiate obstacles is an important component of independent mobility, requiring adaptive locomotor responses to maintain dynamic balance. This study examined the effects of aging and visual-vestibular interactions on whole-body and segmental control during obstacle crossing. Twelve young and 15 older adults walked along a straight pathway and stepped over one obstacle placed in their path. The task was completed under 4 conditions which included intact or blurred vision, and intact or perturbed vestibular information using galvanic vestibular stimulation (GVS). Global task performance significantly increased under suboptimal vision conditions. Vision also significantly influenced medial-lateral center of mass displacement, irrespective of age and GVS. Older adults demonstrated significantly greater trunk pitch and head roll angles under suboptimal vision conditions. Similar to whole-body control, no GVS effect was found for any measures of segmental control. The results indicate a significant reliance on visual but not vestibular information for locomotor control during obstacle crossing. The lack of differences in GVS effects suggests that vestibular information is not up-regulated for obstacle avoidance. This is not differentially affected by aging. In older adults, insufficient visual input appears to affect ability to minimize anterior-posterior trunk movement despite a slower obstacle crossing time and walking speed. Combined with larger medial-lateral deviation of the body COM with insufficient visual information, the older adults may be at a greater risk for imbalance or inability to recover from a possible trip when stepping over an obstacle. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparative anatomy of the vestibular nuclear complex in submammalian vertebrates.

NASA Technical Reports Server (NTRS)

Mehler, W. R.

1972-01-01

A synopsis of the literature on the natural history of the vestibular nuclear complex (VNC) in lower vertebrates is presented in an attempt to assess the knowledge available. The review discloses that there is considerable descriptive information that is widely dispersed in the literature. However, information about the topology, number, and cellular composition of the cell groups that compose the VNC is sketchy. Major cytological and hodological information is still needed to establish which parts of the VNC actually are homologous.

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

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

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.

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.

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.

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.

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.

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.

Modulation of Excitability in the Temporoparietal Junction Relieves Virtual Reality Sickness.

PubMed

Takeuchi, Naoyuki; Mori, Takayuki; Suzukamo, Yoshimi; Izumi, Shin-Ichi

2018-06-01

Virtual reality (VR) immersion often provokes subjective discomfort and postural instability, so called VR sickness. The neural mechanism of VR sickness is speculated to be related to visual-vestibular information mismatch and/or postural instability. However, the approaches proposed to relieve VR sickness through modulation of brain activity are poorly understood. Using transcranial direct current stimulation (tDCS), we aimed to investigate whether VR sickness could be relieved by the modulation of cortical excitability in the temporoparietal junction (TPJ), which is known to be involved in processing of both vestibular and visual information. Twenty healthy subjects received tDCS over right TPJ before VR immersion. The order of the three types of tDCS (anodal, cathodal, and sham) was counterbalanced across subjects. We evaluated the subjective symptoms, heart rate, and center of pressure at baseline, after tDCS, and after VR immersion. VR immersion using head-mounted displays provoked subjective discomfort and postural instability. However, anodal tDCS over right TPJ ameliorated subjective disorientation symptoms and postural instability induced by VR immersion compared with sham condition. The amelioration of VR sickness by anodal tDCS over the right TPJ might result from relief of the sensory conflict and/or facilitation of vestibular function. Our result not only has potential clinical implications for the neuromodulation approach of VR sickness but also implies a causal role of the TPJ in VR sickness.

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).

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 ablation and a semicircular canal prosthesis affect postural stability during head turns

PubMed Central

Thompson, Lara A.; Haburcakova, Csilla; Lewis, Richard F.

2016-01-01

In our study, we examined postural stability during head turns for two rhesus monkeys: one, single animal study contrasted normal and mild bilateral vestibular ablation and a second animal study contrasted severe bilateral vestibular ablation with and without prosthetic stimulation. The monkeys freely stood, unrestrained on a balance platform and made voluntary head turns between visual targets. To quantify each animals’ posture, motions of the head and trunk, as well as torque about the body’s center-of-mass, were measured. In the mildly ablated animal, we observed less foretrunk sway in comparison to the normal state. When the canal prosthesis provided electric stimulation to the severely ablated animal, it showed a decrease in trunk sway during head turns. Because the rhesus monkey with severe bilateral vestibular loss exhibited a decrease in trunk sway when receiving vestibular prosthetic stimulation, we propose that the prosthetic electrical stimulation partially restored head velocity information. Our results provide an indication that a semicircular canal prosthesis may be an effective way to improve postural stability in patients with severe peripheral vestibular dysfunction. PMID:27405997

Effects of bilateral vestibular nucleus lesions on cardiovascular regulation in conscious cats.

PubMed

Mori, R L; Cotter, L A; Arendt, H E; Olsheski, C J; Yates, B J

2005-02-01

The vestibular system participates in cardiovascular regulation during postural changes. In prior studies (Holmes MJ, Cotter LA, Arendt HE, Cas SP, and Yates BJ. Brain Res 938: 62-72, 2002, and Jian BJ, Cotter LA, Emanuel BA, Cass SP, and Yates BJ. J Appl Physiol 86: 1552-1560, 1999), transection of the vestibular nerves resulted in instability in blood pressure during nose-up body tilts, particularly when no visual information reflecting body position in space was available. However, recovery of orthostatic tolerance occurred within 1 wk, presumably because the vestibular nuclei integrate a variety of sensory inputs reflecting body location. The present study tested the hypothesis that lesions of the vestibular nuclei result in persistent cardiovascular deficits during orthostatic challenges. Blood pressure and heart rate were monitored in five conscious cats during nose-up tilts of varying amplitude, both before and after chemical lesions of the vestibular nuclei. Before lesions, blood pressure remained relatively stable during tilts. In all animals, the blood pressure responses to nose-up tilts were altered by damage to the medial and inferior vestibular nuclei; these effects were noted both when animals were tested in the presence and absence of visual feedback. In four of the five animals, the lesions also resulted in augmented heart rate increases from baseline values during 60 degrees nose-up tilts. These effects persisted for longer than 1 wk, but they gradually resolved over time, except in the animal with the worst deficits. These observations suggest that recovery of compensatory cardiovascular responses after loss of vestibular inputs is accomplished at least in part through plastic changes in the vestibular nuclei and the enhancement of the ability of vestibular nucleus neurons to discriminate body position in space by employing nonlabyrinthine signals.

ERG voltage-gated K+ channels regulate excitability and discharge dynamics of the medial vestibular nucleus neurones

PubMed Central

Pessia, Mauro; Servettini, Ilenio; Panichi, Roberto; Guasti, Leonardo; Grassi, Silvarosa; Arcangeli, Annarosa; Wanke, Enzo; Pettorossi, Vito Enrico

2008-01-01

The discharge properties of the medial vestibular nucleus neurones (MVNn) critically depend on the activity of several ion channel types. In this study we show, immunohistochemically, that the voltage-gated K+ channels ERG1A, ERG1B, ERG2 and ERG3 are highly expressed within the vestibular nuclei of P10 and P60 mice. The role played by these channels in the spike-generating mechanisms of the MVNn and in temporal information processing was investigated electrophysiologically from mouse brain slices, in vitro, by analysing the spontaneous discharge and the response to square-, ramp- and sinusoid-like intracellular DC current injections in extracellular and whole-cell patch-clamp studies. We show that more than half of the recorded MVNn were responsive to ERG channel block (WAY-123,398, E4031), displaying an increase in spontaneous activity and discharge irregularity. The response to step and ramp current injection was also modified by ERG block showing a reduction of first spike latency, enhancement of discharge rate and reduction of the slow spike-frequency adaptation process. ERG channels influence the interspike slope without affecting the spike shape. Moreover, in response to sinusoid-like current, ERG channel block caused frequency-dependent gain enhancement and phase-lead shift. Taken together, the data demonstrate that ERG channels control the excitability of MVNn, their discharge regularity and probably their resonance properties. PMID:18718985

ERG voltage-gated K+ channels regulate excitability and discharge dynamics of the medial vestibular nucleus neurones.

PubMed

Pessia, Mauro; Servettini, Ilenio; Panichi, Roberto; Guasti, Leonardo; Grassi, Silvarosa; Arcangeli, Annarosa; Wanke, Enzo; Pettorossi, Vito Enrico

2008-10-15

The discharge properties of the medial vestibular nucleus neurones (MVNn) critically depend on the activity of several ion channel types. In this study we show, immunohistochemically, that the voltage-gated K(+) channels ERG1A, ERG1B, ERG2 and ERG3 are highly expressed within the vestibular nuclei of P10 and P60 mice. The role played by these channels in the spike-generating mechanisms of the MVNn and in temporal information processing was investigated electrophysiologically from mouse brain slices, in vitro, by analysing the spontaneous discharge and the response to square-, ramp- and sinusoid-like intracellular DC current injections in extracellular and whole-cell patch-clamp studies. We show that more than half of the recorded MVNn were responsive to ERG channel block (WAY-123,398, E4031), displaying an increase in spontaneous activity and discharge irregularity. The response to step and ramp current injection was also modified by ERG block showing a reduction of first spike latency, enhancement of discharge rate and reduction of the slow spike-frequency adaptation process. ERG channels influence the interspike slope without affecting the spike shape. Moreover, in response to sinusoid-like current, ERG channel block caused frequency-dependent gain enhancement and phase-lead shift. Taken together, the data demonstrate that ERG channels control the excitability of MVNn, their discharge regularity and probably their resonance properties.

Perception of the dynamic visual vertical during sinusoidal linear motion.

PubMed

Pomante, A; Selen, L P J; Medendorp, W P

2017-10-01

The vestibular system provides information for spatial orientation. However, this information is ambiguous: because the otoliths sense the gravitoinertial force, they cannot distinguish gravitational and inertial components. As a consequence, prolonged linear acceleration of the head can be interpreted as tilt, referred to as the somatogravic effect. Previous modeling work suggests that the brain disambiguates the otolith signal according to the rules of Bayesian inference, combining noisy canal cues with the a priori assumption that prolonged linear accelerations are unlikely. Within this modeling framework the noise of the vestibular signals affects the dynamic characteristics of the tilt percept during linear whole-body motion. To test this prediction, we devised a novel paradigm to psychometrically characterize the dynamic visual vertical-as a proxy for the tilt percept-during passive sinusoidal linear motion along the interaural axis (0.33 Hz motion frequency, 1.75 m/s 2 peak acceleration, 80 cm displacement). While subjects ( n =10) kept fixation on a central body-fixed light, a line was briefly flashed (5 ms) at different phases of the motion, the orientation of which had to be judged relative to gravity. Consistent with the model's prediction, subjects showed a phase-dependent modulation of the dynamic visual vertical, with a subject-specific phase shift with respect to the imposed acceleration signal. The magnitude of this modulation was smaller than predicted, suggesting a contribution of nonvestibular signals to the dynamic visual vertical. Despite their dampening effect, our findings may point to a link between the noise components in the vestibular system and the characteristics of dynamic visual vertical. NEW & NOTEWORTHY A fundamental question in neuroscience is how the brain processes vestibular signals to infer the orientation of the body and objects in space. We show that, under sinusoidal linear motion, systematic error patterns appear in the disambiguation of linear acceleration and spatial orientation. We discuss the dynamics of these illusory percepts in terms of a dynamic Bayesian model that combines uncertainty in the vestibular signals with priors based on the natural statistics of head motion. Copyright © 2017 the American Physiological Society.

Inertial processing of vestibulo-ocular signals

NASA Technical Reports Server (NTRS)

Hess, B. J.; Angelaki, D. E.

1999-01-01

New evidence for a central resolution of gravito-inertial signals has been recently obtained by analyzing the properties of the vestibulo-ocular reflex (VOR) in response to combined lateral translations and roll tilts of the head. It is found that the VOR generates robust compensatory horizontal eye movements independent of whether or not the interaural translatory acceleration component is canceled out by a gravitational acceleration component due to simultaneous roll-tilt. This response property of the VOR depends on functional semicircular canals, suggesting that the brain uses both otolith and semicircular canal signals to estimate head motion relative to inertial space. Vestibular information about dynamic head attitude relative to gravity is the basis for computing head (and body) angular velocity relative to inertial space. Available evidence suggests that the inertial vestibular system controls both head attitude and velocity with respect to a gravity-centered reference frame. The basic computational principles underlying the inertial processing of otolith and semicircular canal afferent signals are outlined.

Modulated discharge of Purkinje and stellate cells persists after unilateral loss of vestibular primary afferent mossy fibers in mice

PubMed Central

Yakhnitsa, V.

2013-01-01

Cerebellar Purkinje cells are excited by two afferent pathways: climbing and mossy fibers. Climbing fibers evoke large “complex spikes” (CSs) that discharge at low frequencies. Mossy fibers synapse on granule cells whose parallel fibers excite Purkinje cells and may contribute to the genesis of “simple spikes” (SSs). Both afferent systems convey vestibular information to folia 9c–10. After making a unilateral labyrinthectomy (UL) in mice, we tested how the discharge of CSs and SSs was changed by the loss of primary vestibular afferent mossy fibers during sinusoidal roll tilt. We recorded from cells identified by juxtacellular neurobiotin labeling. The UL preferentially reduced vestibular modulation of CSs and SSs in folia 8–10 contralateral to the UL. The effects of a UL on Purkinje cell discharge were similar in folia 9c–10, to which vestibular primary afferents project, and in folia 8–9a, to which they do not project, suggesting that vestibular primary afferent mossy fibers were not responsible for the UL-induced alteration of SS discharge. UL also induced reduced vestibular modulation of stellate cell discharge contralateral to the UL. We attribute the decreased modulation to reduced vestibular modulation of climbing fibers. In summary, climbing fibers modulate CSs directly and SSs indirectly through activation of stellate cells. Whereas vestibular primary afferent mossy fibers cannot account for the modulated discharge of SSs or stellate cells, the nonspecific excitation of Purkinje cells by parallel fibers may set an operating point about which the discharges of SSs are sculpted by climbing fibers. PMID:23966673

Visual-vestibular processing deficits in mild traumatic brain injury.

PubMed

Wright, W G; Tierney, R T; McDevitt, J

2017-01-01

The search for reliable and valid signs and symptoms of mild traumatic brain injury (mTBI), commonly synonymous with concussion, has lead to a growing body of evidence that individuals with long-lasting, unremitting impairments often experience visual and vestibular symptoms, such as dizziness, postural and gait disturbances. Investigate the role of visual-vestibular processing deficits following concussion. A number of clinically accepted vestibular, oculomotor, and balance assessments as well as a novel virtual reality (VR)-based balance assessment device were used to assess adults with post-acute concussion (n = 14) in comparison to a healthy age-matched cohort (n = 58). Significant between-group differences were found with the VR-based balance device (p = 0.001), with dynamic visual motion emerging as the most discriminating balance condition. The symptom reports collected after performing the oculomotor and vestibular tests: rapid alternating horizontal eye saccades, optokinetic stimulation, and gaze stabilization, were all sensitive to health status (p < 0.05), despite the absence of oculomotor abnormalities being observed, except for near-point convergence. The BESS, King-Devick, and Dynamic Visual Acuity tests did not detect between-group differences. Postural and visual-vestibular tasks most closely linked to spatial and self-motion perception had the greatest discriminatory outcomes. The current findings suggest that mesencephalic and parieto-occipital centers and pathways may be involved in concussion.

Demyelination of vestibular nerve axons in unilateral Ménière's disease.

PubMed

Spencer, Robert F; Sismanis, Aristides; Kilpatrick, Jefferson K; Shaia, Wayne T

2002-11-01

We conducted a study to determine whether vestibular nerves in patients with unilateral Ménière's disease whose symptoms are refractory to medical management exhibit neuropathologic changes. We also endeavored to determine whether retrocochlear abnormalities are primary or secondary factors in the disease process. To these ends, we obtained vestibular nerve segments from five patients during retrosigmoid (posterior fossa) neurectomy, immediately fixed them, and processed them for light and electron microscopy. We found that all five segments exhibited moderate to severe demyelination with axonal sparing. Moreover, we noted that reactive astrocytes produced an extensive proliferation of fibrous processes and that the microglia assumed a phagocytic role. We conclude that the possible etiologies of demyelination include viral and/or immune-mediated factors similar to those seen in other demyelinating diseases, such as multiple sclerosis and Guillain-Barré syndrome. Our findings suggest that some forms of Ménière's disease that are refractory to traditional medical management might be the result of retrocochlear pathology that affects the neuroglial portion of the vestibular nerve.

Development and Function of the Mouse Vestibular System in the Absence of Gravity Perception

NASA Technical Reports Server (NTRS)

Wolgemuth, Debra J.

2005-01-01

The hypothesis that was tested in this research was that the absence of gravity perception, such as would occur in space, would affect the development and function of the vestibular and central nervous systems. Further, we postulated that these effects would be more significant at specific stages of post-natal development of the animal. We also proposed the use of molecular genetic approaches that would provide important information as to the hierarchy of gene function during the development and subsequent function of the vestibular system. The tilted (tlt) mutant mouse has been characterized as lacking the ability to provide sensory input to the gravity receptors. The tlt/tlt mutant mice were a particularly attractive model for the study of vestibular function since the primary defect was limited to the receptor part of the vestibular system, and there were no detectable abnormal phenotypes in other organ systems. The goal of the proposed studies was to assess immediate and delayed effects of the lack of gravity perception on the vestibular system. Particular attention was paid to characterizing primarily affected periods of vestibular morphogenesis, and to identifying downstream genetic pathways that are altered in the CNS of the tlt/tlt mutant mouse. The specific aims were: (1) to characterize the postnatal morphogenesis of the CNS in the tlt mutant mouse, using detailed morphometric analysis of isolated vestibular ganglia and brain tissue at different stages of postnatal development and assessment of apoptotic cell death; (2) to examine the expression of selected genes implicated by mutational analysis to be important in vestibular development or function by in situ hybridization or immunohistochemistry in the mutant mice; and (3) to identify other genes involved in vestibular development and function, using differential cloning strategies to isolate genes whose expression is changed in the mutant versus normal vestibular system.

Gamma Knife radiosurgery for vestibular schwannoma: case report and review of the literature

PubMed Central

2009-01-01

Vestibular schwannomas, also called acoustic neuromas, are benign tumors of the vestibulocochlear nerve. Patients with these tumours almost always present with signs of hearing loss, and many also experience tinnitus, vertigo, and equilibrium problems. Following diagnosis with contrast enhanced MRI, patients may choose to observe the tumour with subsequent scans or seek active treatment in the form of microsurgery, radiosurgery, or radiotherapy. Unfortunately, definitive guidelines for treating vestibular schwannomas are lacking, because of insufficient evidence comparing the outcomes of therapeutic modalities. We present a contemporary case report, describing the finding of a vestibular schwannoma in a patient who presented with dizziness and a "clicking" sensation in the ear, but no hearing deficit. Audible clicking is a symptom that, to our knowledge, has not been associated with vestibular schwannoma in the literature. We discuss the diagnosis and patient's decision-making process, which led to treatment with Gamma Knife radiosurgery. Treatment resulted in an excellent radiographic response and complete hearing preservation. This case highlights an atypical presentation of vestibular schwannoma, associated with audible "clicks" and normal hearing. We also provide a concise review of the available literature on modern vestibular schwannoma treatment, which may be useful in guiding treatment decisions. PMID:20021676

Gamma Knife radiosurgery for vestibular schwannoma: case report and review of the literature.

PubMed

Arthurs, Benjamin J; Lamoreaux, Wayne T; Giddings, Neil A; Fairbanks, Robert K; Mackay, Alexander R; Demakas, John J; Cooke, Barton S; Lee, Christopher M

2009-12-18

Vestibular schwannomas, also called acoustic neuromas, are benign tumors of the vestibulocochlear nerve. Patients with these tumours almost always present with signs of hearing loss, and many also experience tinnitus, vertigo, and equilibrium problems. Following diagnosis with contrast enhanced MRI, patients may choose to observe the tumour with subsequent scans or seek active treatment in the form of microsurgery, radiosurgery, or radiotherapy. Unfortunately, definitive guidelines for treating vestibular schwannomas are lacking, because of insufficient evidence comparing the outcomes of therapeutic modalities.We present a contemporary case report, describing the finding of a vestibular schwannoma in a patient who presented with dizziness and a "clicking" sensation in the ear, but no hearing deficit. Audible clicking is a symptom that, to our knowledge, has not been associated with vestibular schwannoma in the literature. We discuss the diagnosis and patient's decision-making process, which led to treatment with Gamma Knife radiosurgery. Treatment resulted in an excellent radiographic response and complete hearing preservation. This case highlights an atypical presentation of vestibular schwannoma, associated with audible "clicks" and normal hearing. We also provide a concise review of the available literature on modern vestibular schwannoma treatment, which may be useful in guiding treatment decisions.

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

Partial segregation of posterior crista and saccular fibers to the nodulus and uvula of the cerebellum in mice, and its development

NASA Technical Reports Server (NTRS)

Maklad, Adel; Fritzsch, Bernd

2003-01-01

The projection of the posterior canal crista and saccular afferents to the cerebellum of embryonic and neonatal mice was investigated using carbocyanine dyes. Anterograde tracing from these two endorgans reveals a partial segregation of these two sets of afferents. The saccule projects predominantly to the uvula, with very minor input to the nodulus. The posterior canal projects mainly to the nodulus and, to a lesser extent, to the uvula. Retrograde tracing from the uvula and nodulus confirms this partial segregation for these two endorgans and extends it to other vestibular endorgans. Uvular injections result in many more labeled fibers in the gravistatic maculae than in the canals' cristae. In contrast, nodular injection reveals many more labeled fibers in the canal cristae than in the gravistatic maculae. This partial segregation may play a role in the information processing in these folia. Our developmental data suggest that the initial segregation at E17 coincides with the formation of the postero-lateral fissure. This embryonic segregation of the primary vestibular mossy fibers to the uvula and nodulus commences long before the maturity of their targets, the granule cells and unipolar brush cells. Thus, the segregation of the primary vestibular projection to the uvula and nodulus does not depend on cues related to the target cells. Rather, the segregation may reflect more global cerebellar patterning mechanisms involving guidance for the vestibular afferent fibers independent of the future target cells.

Being Moved by the Self and Others: Influence of Empathy on Self-Motion Perception

PubMed Central

Lopez, Christophe; Falconer, Caroline J.; Mast, Fred W.

2013-01-01

Background The observation of conspecifics influences our bodily perceptions and actions: Contagious yawning, contagious itching, or empathy for pain, are all examples of mechanisms based on resonance between our own body and others. While there is evidence for the involvement of the mirror neuron system in the processing of motor, auditory and tactile information, it has not yet been associated with the perception of self-motion. Methodology/Principal Findings We investigated whether viewing our own body, the body of another, and an object in motion influences self-motion perception. We found a visual-vestibular congruency effect for self-motion perception when observing self and object motion, and a reduction in this effect when observing someone else's body motion. The congruency effect was correlated with empathy scores, revealing the importance of empathy in mirroring mechanisms. Conclusions/Significance The data show that vestibular perception is modulated by agent-specific mirroring mechanisms. The observation of conspecifics in motion is an essential component of social life, and self-motion perception is crucial for the distinction between the self and the other. Finally, our results hint at the presence of a “vestibular mirror neuron system”. PMID:23326302

The cortical spatiotemporal correlate of otolith stimulation: Vestibular evoked potentials by body translations.

PubMed

Ertl, M; Moser, M; Boegle, R; Conrad, J; Zu Eulenburg, P; Dieterich, M

2017-07-15

The vestibular organ senses linear and rotational acceleration of the head during active and passive motion. These signals are necessary for bipedal locomotion, navigation, the coordination of eye and head movements in 3D space. The temporal dynamics of vestibular processing in cortical structures have hardly been studied in humans, let alone with natural stimulation. The aim was to investigate the cortical vestibular network related to natural otolith stimulation using a hexapod motion platform. We conducted two experiments, 1. to estimate the sources of the vestibular evoked potentials (VestEPs) by means of distributed source localization (n=49), and 2. to reveal modulations of the VestEPs through the underlying acceleration intensity (n=24). For both experiments subjects were accelerated along the main axis (left/right, up/down, fore/aft) while the EEG was recorded. We were able to identify five VestEPs (P1, N1, P2, N2, P3) with latencies between 38 and 461 ms as well as an evoked beta-band response peaking with a latency of 68 ms in all subjects and for all acceleration directions. Source localization gave the cingulate sulcus visual (CSv) area and the opercular-insular region as the main origin of the evoked potentials. No lateralization effects due to handedness could be observed. In the second experiment, area CSv was shown to be integral in the processing of acceleration intensities as sensed by the otolith organs, hinting at its potential role in ego-motion detection. These robust VestEPs could be used to investigate the mechanisms of inter-regional interaction in the natural context of vestibular processing and multisensory integration. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

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

Processing of visual gravitational motion in the peri-sylvian cortex: Evidence from brain-damaged patients.

PubMed

Maffei, Vincenzo; Mazzarella, Elisabetta; Piras, Fabrizio; Spalletta, Gianfranco; Caltagirone, Carlo; Lacquaniti, Francesco; Daprati, Elena

2016-05-01

Rich behavioral evidence indicates that the brain estimates the visual direction and acceleration of gravity quite accurately, and the underlying mechanisms have begun to be unraveled. While the neuroanatomical substrates of gravity direction processing have been studied extensively in brain-damaged patients, to our knowledge no such study exists for the processing of visual gravitational motion. Here we asked 31 stroke patients to intercept a virtual ball moving along the vertical under either natural gravity or artificial reversed gravity. Twenty-seven of them also aligned a luminous bar to the vertical direction (subjective visual vertical, SVV). Using voxel-based lesion-symptom mapping as well as lesion subtraction analysis, we found that lesions mainly centered on the posterior insula are associated with greater deviations of SVV, consistent with several previous studies. Instead, lesions mainly centered on the parietal operculum decrease the ability to discriminate natural from unnatural gravitational acceleration with a timed motor response in the interception task. Both the posterior insula and the parietal operculum belong to the vestibular cortex, and presumably receive multisensory information about the gravity vector. We speculate that an internal model estimating the effects of gravity on visual objects is constructed by transforming the vestibular estimates of mechanical gravity, which are computed in the brainstem and cerebellum, into internalized estimates of virtual gravity, which are stored in the cortical vestibular network. The present lesion data suggest a specific role for the parietal operculum in detecting the mismatch between predictive signals from the internal model and the online visual signals. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

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

PubMed

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

2013-09-01

Background In previous imaging studies the insular cortex (IC) has been identified as an essential part of the processing of a wide spectrum of perception and sensorimotor integration. Yet, there are no systematic lesion studies in a sufficient number of patients examining whether processing of vestibular and the interaction of somatosensory and vestibular signals take place in the IC. Methods We investigated acute stroke patients with lesions affecting the IC in order to fill this gap. In detail, we explored signs of a vestibular tone imbalance such as the deviation of the subjective visual vertical (SVV). We applied voxel-lesion behaviour mapping analysis in 27 patients with acute unilateral stroke. Results Our data demonstrate that patients with lesions of the posterior IC have an abnormal tilt of SVV. Furthermore, re-analysing data of 20 patients from a previous study, we found a positive correlation between thermal perception contralateral to the stroke and the severity of the SVV tilt. Conclusions We conclude that the IC is a sensory brain region where different modalities might interact.

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

NASA Technical Reports Server (NTRS)

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

2002-01-01

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

Physical and sporting activities improve vestibular afferent usage and balance in elderly human subjects.

PubMed

Gauchard, G C; Jeandel, C; Perrin, P P

2001-01-01

Ageing is associated with a reduction in balance, in particular through dysfunction of each level of postural control, which results in an increased risk of falling. Conversely, the practice of physical activities has been shown to modulate postural control in elderly people. This study examined the potential positive effects of two types of regular physical and sporting activities on vestibular information and their relation to posture. Gaze and postural stabilisation was evaluated by caloric and rotational vestibular tests on 18 healthy subjects over the age of 60 who regularly practised low-energy or bioenergetic physical activities and on 18 controls of a similar age who only walked on a regular basis. These subjects were also submitted to static and dynamic posturographic tests. The control group displayed less balance control, with a lower vestibular sensitivity and a relatively high dependency on vision compared to the group practising low-energy physical activities, which had better postural control with good vestibular sensitivity and less dependency on vision. The postural control and vestibular sensitivity of subjects practising bioenergetic activities was average, and required higher visual afferent contribution. Low-energy exercises, already shown to have the most positive impact on balance control by relying more on proprioception, also appear to develop or maintain a high level of vestibular sensitivity allowing elderly people practising such exercises to reduce the weight of vision. Copyright 2001 S. Karger AG, Basel

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.

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

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.

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

Evaluation of Galvanic Vestibular Stimulation System

NASA Technical Reports Server (NTRS)

Kofman, I. S.; Warren, E.; DeSoto, R.; Moroney, G.; Chastain, J.; De Dios, Y. E.; Gadd, N.; Taylor, L.; Peters, B. T.; Allen, E.;

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.

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.

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.

Visual Dependency and Dizziness after Vestibular Neuritis

PubMed Central

Cousins, Sian; Cutfield, Nicholas J.; Kaski, Diego; Palla, Antonella; Seemungal, Barry M.; Golding, John F.; Staab, Jeffrey P.; Bronstein, Adolfo M.

2014-01-01

Symptomatic recovery after acute vestibular neuritis (VN) is variable, with around 50% of patients reporting long term vestibular symptoms; hence, it is essential to identify factors related to poor clinical outcome. Here we investigated whether excessive reliance on visual input for spatial orientation (visual dependence) was associated with long term vestibular symptoms following acute VN. Twenty-eight patients with VN and 25 normal control subjects were included. Patients were enrolled at least 6 months after acute illness. Recovery status was not a criterion for study entry, allowing recruitment of patients with a full range of persistent symptoms. We measured visual dependence with a laptop-based Rod-and-Disk Test and severity of symptoms with the Dizziness Handicap Inventory (DHI). The third of patients showing the worst clinical outcomes (mean DHI score 36–80) had significantly greater visual dependence than normal subjects (6.35° error vs. 3.39° respectively, p = 0.03). Asymptomatic patients and those with minor residual symptoms did not differ from controls. Visual dependence was associated with high levels of persistent vestibular symptoms after acute VN. Over-reliance on visual information for spatial orientation is one characteristic of poorly recovered vestibular neuritis patients. The finding may be clinically useful given that visual dependence may be modified through rehabilitation desensitization techniques. PMID:25233234

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.

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

PubMed

Best, C; Tschan, R; Eckhardt-Henn, A; Dieterich, M

2009-12-29

Patients with vestibular vertigo syndromes often suffer from anxiety and depression, whereas patients with psychiatric disorders often experience subjective unsteadiness, dizziness, or vertigo. Thus, it has been hypothesized that the vestibular system may be interlinked with the emotion processing systems. The aim of the current study was to evaluate this hypothesis by correlating vestibular and psychiatric symptoms with the course of the disease over 1 year. This interdisciplinary, prospective, longitudinal study included a total of 68 patients with acute vestibular vertigo syndromes. Four subgroups of patients with benign paroxysmal positioning vertigo (BPPV, n=19), acute vestibular neuritis (VN, n=14), vestibular migraine (VM, n=27), or Menière's disease (MD, n=8) were compared. All patients underwent neurological and neuro-otological examinations and filled out standardized self-report inventories including the Vertigo Symptom Scale (VSS), the Vertigo Handicap Questionnaire (VHQ) and the Symptom Checklist 90R (GSI, SCL-90R) at five different times (T0-T4) in the course of 1 year. VM patients experienced significantly more "vertigo and related symptoms" (VSS-VER), "somatic anxiety and autonomic arousal" (VSS-AA), and "vertigo induced handicap" (VHQ) than all other patients (P<0.001-P=0.006). Patients with a positive history of psychiatric disorders had significantly more emotional distress (GSI, SCL-90R), regardless of the specific phenomenology of the four diagnostic subgroups. Finally, fluctuations of vestibular excitability correlated positively with the extent of subjectively perceived vertigo. VM patients are significantly more handicapped by vertigo and related symptoms. They show significantly elevated fluctuations of vestibular excitability, which correlate with the (subjective) severity of vertigo symptoms.

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.

Histological preparation of developing vestibular otoconia for scanning electron microscopy

NASA Technical Reports Server (NTRS)

Huss, D.; Dickman, J. D.

2003-01-01

The unique nature of vestibular otoconia as calcium carbonate biominerals makes them particularly susceptible to chemical deformation during histological processing. We fixed and stored otoconia from all three otolith endorgans of embryonic, hatchling and adult Japanese quail in glutaraldehyde containing either phosphate or non-phosphate buffers for varying lengths of time and processed them for scanning electron microscopy. Otoconia from all age groups and otolith endorgans processed in 0.1 M phosphate buffer (pH 7.4) showed abnormal surface morphology when compared to acetone fixed controls. Otoconia processed in 0.1 M sodium cacodylate or HEPES buffered artificial endolymph (pH 7.4) showed normal morphology that was similar to controls. The degree of otoconial deformation was directly related to the time exposed to phosphate buffer. Short duration exposure produced particulate deformations while longer exposures resulted in fused otoconia that formed solid sheets. Otoconial surface deformation and fusing was independent of the glutaraldehyde component of the histological processing. These findings should help vestibular researchers to develop appropriate histological processing protocols in future studies of otoconia.

Rapid adaptation of multisensory integration in vestibular pathways

PubMed Central

Carriot, Jerome; Jamali, Mohsen; Cullen, Kathleen E.

2015-01-01

Sensing gravity is vital for our perception of spatial orientation, the control of upright posture, and generation of our everyday activities. When an astronaut transitions to microgravity or returns to earth, the vestibular input arising from self-motion will not match the brain's expectation. Our recent neurophysiological studies have provided insight into how the nervous system rapidly reorganizes when vestibular input becomes unreliable by both (1) updating its internal model of the sensory consequences of motion and (2) up-weighting more reliable extra-vestibular information. These neural strategies, in turn, are linked to improvements in sensorimotor performance (e.g., gaze and postural stability, locomotion, orienting) and perception characterized by similar time courses. We suggest that furthering our understanding of the neural mechanisms that underlie sensorimotor adaptation will have important implications for optimizing training programs for astronauts before and after space exploration missions and for the design of goal-oriented rehabilitation for patients. PMID:25932009

Perception and performance in flight simulators: The contribution of vestibular, visual, and auditory information

NASA Technical Reports Server (NTRS)

1979-01-01

The pilot's perception and performance in flight simulators is examined. The areas investigated include: vestibular stimulation, flight management and man cockpit information interfacing, and visual perception in flight simulation. The effects of higher levels of rotary acceleration on response time to constant acceleration, tracking performance, and thresholds for angular acceleration are examined. Areas of flight management examined are cockpit display of traffic information, work load, synthetic speech call outs during the landing phase of flight, perceptual factors in the use of a microwave landing system, automatic speech recognition, automation of aircraft operation, and total simulation of flight training.

Efferent innervation of turtle semicircular canal cristae: comparisons with bird and mouse

PubMed Central

Jordan, Paivi M.; Fettis, Margaret; Holt, Joseph C.

2014-01-01

In the vestibular periphery of nearly every vertebrate, cholinergic vestibular efferent neurons give rise to numerous presynaptic varicosities that target hair cells and afferent processes in the sensory neuroepithelium. Although pharmacological studies have described the postsynaptic actions of vestibular efferent stimulation in several species, characterization of efferent innervation patterns and the relative distribution of efferent varicosities among hair cells and afferents are also integral to understanding how efferent synapses operate. Vestibular efferent markers, however, have not been well characterized in the turtle, one of the animal models utilized by our laboratory. Here, we sought to identify reliable efferent neuronal markers in the vestibular periphery of turtle, to utilize these markers to understand how efferent synapses are organized, and to compare efferent neuronal labeling patterns in turtle with two other amniotes using some of the same markers. Efferent fibers and varicosities were visualized in the semicircular canal of Red-Eared Turtles (Trachemys scripta elegans), Zebra Finches (Taeniopygia guttata), and mice (Mus musculus) utilizing fluorescent immunohistochemistry with antibodies against choline acetyltransferase (ChAT). Vestibular hair cells and afferents were counterstained using antibodies to myosin VIIa and calretinin. In all species, ChAT labeled a population of small diameter fibers giving rise to numerous spherical varicosities abutting type II hair cells and afferent processes. That these ChAT-positive varicosities represent presynaptic release sites were demonstrated by colabeling with antibodies against the synaptic vesicle proteins synapsin I, SV2, or syntaxin and the neuropeptide calcitonin gene-related peptide (CGRP). Comparisons of efferent innervation patterns among the three species are discussed. PMID:25560461

Efferent innervation of turtle semicircular canal cristae: comparisons with bird and mouse.

PubMed

Jordan, Paivi M; Fettis, Margaret; Holt, Joseph C

2015-06-01

In the vestibular periphery of nearly every vertebrate, cholinergic vestibular efferent neurons give rise to numerous presynaptic varicosities that target hair cells and afferent processes in the sensory neuroepithelium. Although pharmacological studies have described the postsynaptic actions of vestibular efferent stimulation in several species, characterization of efferent innervation patterns and the relative distribution of efferent varicosities among hair cells and afferents are also integral to understanding how efferent synapses operate. Vestibular efferent markers, however, have not been well characterized in the turtle, one of the animal models used by our laboratory. Here we sought to identify reliable efferent neuronal markers in the vestibular periphery of turtle, to use these markers to understand how efferent synapses are organized, and to compare efferent neuronal labeling patterns in turtle with two other amniotes using some of the same markers. Efferent fibers and varicosities were visualized in the semicircular canal of red-eared turtles (Trachemys scripta elegans), zebra finches (Taeniopygia guttata), and mice (Mus musculus) utilizing fluorescent immunohistochemistry with antibodies against choline acetyltransferase (ChAT). Vestibular hair cells and afferents were counterstained using antibodies to myosin VIIa and calretinin. In all species, ChAT labeled a population of small diameter fibers giving rise to numerous spherical varicosities abutting type II hair cells and afferent processes. That these ChAT-positive varicosities represent presynaptic release sites were demonstrated by colabeling with antibodies against the synaptic vesicle proteins synapsin I, SV2, or syntaxin and the neuropeptide calcitonin gene-related peptide. Comparisons of efferent innervation patterns among the three species are discussed. © 2015 Wiley Periodicals, Inc.

Firing behavior of vestibular neurons during active and passive head movements: vestibulo-spinal and other non-eye-movement related neurons

NASA Technical Reports Server (NTRS)

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

1999-01-01

The firing behavior of 51 non-eye movement related central vestibular neurons that were sensitive to passive head rotation in the plane of the horizontal semicircular canal was studied in three squirrel monkeys whose heads were free to move in the horizontal plane. Unit sensitivity to active head movements during spontaneous gaze saccades was compared with sensitivity to passive head rotation. Most units (29/35 tested) were activated at monosynaptic latencies following electrical stimulation of the ipsilateral vestibular nerve. Nine were vestibulo-spinal units that were antidromically activated following electrical stimulation of the ventromedial funiculi of the spinal cord at C1. All of the units were less sensitive to active head movements than to passive whole body rotation. In the majority of cells (37/51, 73%), including all nine identified vestibulo-spinal units, the vestibular signals related to active head movements were canceled. The remaining units (n = 14, 27%) were sensitive to active head movements, but their responses were attenuated by 20-75%. Most units were nearly as sensitive to passive head-on-trunk rotation as they were to whole body rotation; this suggests that vestibular signals related to active head movements were cancelled primarily by subtraction of a head movement efference copy signal. The sensitivity of most units to passive whole body rotation was unchanged during gaze saccades. A fundamental feature of sensory processing is the ability to distinguish between self-generated and externally induced sensory events. Our observations suggest that the distinction is made at an early stage of processing in the vestibular system.

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.

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.;

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

Immunohistochemical profile of cytokines and growth factors expressed in vestibular schwannoma and in normal vestibular nerve tissue.

PubMed

Taurone, Samanta; Bianchi, Enrica; Attanasio, Giuseppe; Di Gioia, Cira; Ierinó, Rocco; Carubbi, Cecilia; Galli, Daniela; Pastore, Francesco Saverio; Giangaspero, Felice; Filipo, Roberto; Zanza, Christian; Artico, Marco

2015-07-01

Vestibular schwannomas, also known as acoustic neuromas, are benign tumors, which originate from myelin-forming Schwann cells. They develop in the vestibular branch of the eighth cranial nerve in the internal auditory canal or cerebellopontine angle. The clinical progression of the condition involves slow and progressive growth, eventually resulting in brainstem compression. The objective of the present study was to investigate the expression level and the localization of the pro-inflammatory cytokines, transforming growth factor-β1 (TGF-β1) interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α), as well as the adhesion molecules, intracellular adhesion molecule-1 and vascular endothelial growth factor (VEGF), in order to determine whether these factors are involved in the transformation and development of human vestibular schwannoma. The present study investigated whether changes in inflammation are involved in tumor growth and if so, the mechanisms underlying this process. The results of the current study demonstrated that pro-inflammatory cytokines, including TGF-β1, IL-1β and IL-6 exhibited increased expression in human vestibular schwannoma tissue compared with normal vestibular nerve samples. TNF-α was weakly expressed in Schwann cells, confirming that a lower level of this cytokine is involved in the proliferation of Schwann cells. Neoplastic Schwann cells produce pro-inflammatory cytokines that may act in an autocrine manner, stimulating cellular proliferation. In addition, the increased expression of VEGF in vestibular schwannoma compared with that in normal vestibular nerve tissue, suggests that this factor may induce neoplastic growth via the promotion of angiogenesis. The present findings suggest that inflammation may promote angiogenesis and consequently contribute to tumor progression. In conclusion, the results of the present study indicated that VEGF and pro-inflammatory cytokines may be potential therapeutic targets in vestibular schwannoma. Further studies are necessary to confirm the involvement of these factors in the growth of neoplasms and to develop inhibitors of pro-inflammatory cytokines as a potential treatment option in the future.

Integration of vestibular and head movement signals in the vestibular nuclei during whole-body rotation

NASA Technical Reports Server (NTRS)

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

1999-01-01

Single-unit recordings were obtained from 107 horizontal semicircular canal-related central vestibular neurons in three alert squirrel monkeys during passive sinusoidal whole-body rotation (WBR) while the head was free to move in the yaw plane (2.3 Hz, 20 degrees /s). Most of the units were identified as secondary vestibular neurons by electrical stimulation of the ipsilateral vestibular nerve (61/80 tested). Both non-eye-movement (n = 52) and eye-movement-related (n = 55) units were studied. Unit responses recorded when the head was free to move were compared with responses recorded when the head was restrained from moving. WBR in the absence of a visual target evoked a compensatory vestibulocollic reflex (VCR) that effectively reduced the head velocity in space by an average of 33 +/- 14%. In 73 units, the compensatory head movements were sufficiently large to permit the effect of the VCR on vestibular signal processing to be assessed quantitatively. The VCR affected the rotational responses of different vestibular neurons in different ways. Approximately one-half of the units (34/73, 47%) had responses that decreased as head velocity decreased. However, the responses of many other units (24/73) showed little change. These cells had signals that were better correlated with trunk velocity than with head velocity. The remaining units had responses that were significantly larger (15/73, 21%) when the VCR produced a decrease in head velocity. Eye-movement-related units tended to have rotational responses that were correlated with head velocity. On the other hand, non-eye-movement units tended to have rotational responses that were better correlated with trunk velocity. We conclude that sensory vestibular signals are transformed from head-in-space coordinates to trunk-in-space coordinates on many secondary vestibular neurons in the vestibular nuclei by the addition of inputs related to head rotation on the trunk. This coordinate transformation is presumably important for controlling postural reflexes and constructing a central percept of body orientation and movement in space.

Spatial Orientation in Flight

DTIC Science & Technology

1993-11-01

activating system or the vestibular efferent system , or both, are responsible for the resulting heightened arousal and enhanced vestibular information...the emetic response to poisons. When an animal ingests a tý.xc substance and experiences its effects on the central nervous system ---,m,-!y...ACCELERATION ax,xy,az ANGULAR REACTION RxRy,Rz Figure 2. System for describing acceleratiots and inertial reactions in humans . (Adapted from Hixson et

Studies of the Interactions Between Vestibular Function and Tactual Orientation Display Systems

NASA Technical Reports Server (NTRS)

Cholewiak, Roger W.; Reschke, Millard F.

1997-01-01

When humans experience conditions in which internal vestibular cues to movement or spatial location are challenged or contradicted by external visual information, the result can be spatial disorientation, often leading to motion sickness. Spatial disorientation can occur in any situation in which the individual is passively moved in the environment, but is most common in automotive, aircraft, or undersea travel. Significantly, the incidence of motion sickness in space travel is great: The majority of individuals in Shuttle operations suffer from the syndrome. Even after the space-sickness-producing influences of spatial disorientation dissipate, usually within several days, there are other situations in which, because of the absence of reliable or familiar vestibular cues, individuals in space still experience disorientation, resulting in a reliance on the already preoccupied sense of vision. One possible technique to minimize the deleterious effects of spatial disorientation might be to present attitude information (including orientation, direction, and motion) through another less-used sensory modality - the sense of touch. Data from experiences with deaf and blind persons indicate that this channel can provide useful communication and mobility information on a real-time basis. More recently, technologies have developed to present effective attitude information to pilots in situations in which dangerously ambiguous and conflicting visual and vestibular sensations occur. This summers project at NASA-Johnson Space Center will evaluate the influence of motion-based spatial disorientation on the perception of tactual stimuli representing veridical position and orientation information, presented by new dynamic vibrotactile array display technologies. In addition, the possibility will be explored that tactile presentations of motion and direction from this alternative modality might be useful in mitigating or alleviating spatial disorientation produced by multi-axis rotatory systems, monitored by physiological recording techniques developed at JSC.

Responses of non-eye movement central vestibular neurons to sinusoidal horizontal translation in compensated macaques after unilateral labyrinthectomy

PubMed Central

Lin, Nan; Wei, Min

2014-01-01

After vestibular labyrinth injury, behavioral deficits partially recover through the process of vestibular compensation. The present study was performed to improve our understanding of the physiology of the macaque vestibular system in the compensated state (>7 wk) after unilateral labyrinthectomy (UL). Three groups of vestibular nucleus neurons were included: pre-UL control neurons, neurons ipsilateral to the lesion, and neurons contralateral to the lesion. The firing responses of neurons sensitive to linear acceleration in the horizontal plane were recorded during sinusoidal horizontal translation directed along six different orientations (30° apart) at 0.5 Hz and 0.2 g peak acceleration (196 cm/s2). This data defined the vector of best response for each neuron in the horizontal plane, along which sensitivity, symmetry, detection threshold, and variability of firing were determined. Additionally, the responses of the same cells to translation over a series of frequencies (0.25–5.0 Hz) either in the interaural or naso-occipital orientation were obtained to define the frequency response characteristics in each group. We found a decrease in sensitivity, increase in threshold, and alteration in orientation of best responses in the vestibular nuclei after UL. Additionally, the phase relationship of the best neural response to translational stimulation changed with UL. The symmetry of individual neuron responses in the excitatory and inhibitory directions was unchanged by UL. Bilateral central utricular neurons still demonstrated two-dimension tuning after UL, consistent with spatio-temporal convergence from a single vestibular end-organ. These neuronal data correlate with known behavioral deficits after unilateral vestibular compromise. PMID:24717349

Tumor Biology of Vestibular Schwannoma: A Review of Experimental Data on the Determinants of Tumor Genesis and Growth Characteristics.

PubMed

de Vries, Maurits; van der Mey, Andel G L; Hogendoorn, Pancras C W

2015-08-01

Provide an overview of the literature on vestibular schwannoma biology with special attention to tumor behavior and targeted therapy. Vestibular schwannomas are benign tumors originating from the eighth cranial nerve and arise due to inactivation of the NF2 gene and its product merlin. Unraveling the biology of these tumors helps to clarify their growth pattern and is essential in identifying therapeutic targets. PubMed search for English-language articles on vestibular schwannoma biology from 1994 to 2014. Activation of merlin and its role in cell signaling seem as key aspects of vestibular schwannoma biology. Merlin is regulated by proteins such as CD44, Rac, and myosin phosphatase-targeting subunit 1. The tumor-suppressive functions of merlin are related to receptor tyrosine kinases, such as the platelet-derived growth factor receptor and vascular endothelial growth factor receptor. Merlin mediates the Hippo pathway and acts within the nucleus by binding E3 ubiquiting ligase CRL4. Angiogenesis is an important mechanism responsible for the progression of these tumors and is affected by processes such as hypoxia and inflammation. Inhibiting angiogenesis by targeting vascular endothelial growth factor receptor seems to be the most successful pharmacologic strategy, but additional therapeutic options are emerging. Over the years, the knowledge on vestibular schwannoma biology has significantly increased. Future research should focus on identifying new therapeutic targets by investigating vestibular schwannoma (epi)genetics, merlin function, and tumor behavior. Besides identifying novel targets, testing new combinations of existing treatment strategies can further improve vestibular schwannoma therapy.

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

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.

Assessing Somatosensory Utilization during Unipedal Postural Control.

PubMed

Goel, Rahul; De Dios, Yiri E; Gadd, Nichole E; Caldwell, Erin E; Peters, Brian T; Reschke, Millard F; Bloomberg, Jacob J; Oddsson, Lars I E; Mulavara, Ajitkumar P

2017-01-01

Multisensory-visual, vestibular and somatosensory information is integrated for appropriate postural control. The primary goal of this study was to assess somatosensory utilization during a functional motor task of unipedal postural control, in normal healthy adults. Assessing individual bias in the utilization of individual sensory contributions during postural control may help customization of rehabilitation protocols. In this study, a test paradigm of unipedal stance control in supine orientation with and without vision was assessed. Postural control in this test paradigm was hypothesized to utilize predominantly contributions of somatosensory information from the feet and ankle joint, with minimal vestibular input. Fourteen healthy subjects "stood" supine on their dominant leg while strapped to a backpack frame that was freely moving on air-bearings, to remove available otolith tilt cues with respect to gravity that influences postural control when standing upright. The backpack was attached through a cable to a pneumatic cylinder that provided a gravity-like load. Subjects performed three trials each with Eyes-open (EO) and Eyes-closed (EC) while loaded with 60% body weight. There was no difference in unipedal stance time (UST) across the two conditions with EC condition challenging the postural control system greater than the EO condition. Stabilogram-diffusion analysis (SDA) indicated that the critical mean square displacement was significantly different between the two conditions. Vestibular cues, both in terms of magnitude and the duration for which relevant information was available for postural control in this test paradigm, were minimized. These results support our hypothesis that maintaining unipedal stance in supine orientation without vision, minimizes vestibular contribution and thus predominantly utilizes somatosensory information for postural control.

Assessing Somatosensory Utilization during Unipedal Postural Control

PubMed Central

Goel, Rahul; De Dios, Yiri E.; Gadd, Nichole E.; Caldwell, Erin E.; Peters, Brian T.; Reschke, Millard F.; Bloomberg, Jacob J.; Oddsson, Lars I. E.; Mulavara, Ajitkumar P.

2017-01-01

Multisensory—visual, vestibular and somatosensory information is integrated for appropriate postural control. The primary goal of this study was to assess somatosensory utilization during a functional motor task of unipedal postural control, in normal healthy adults. Assessing individual bias in the utilization of individual sensory contributions during postural control may help customization of rehabilitation protocols. In this study, a test paradigm of unipedal stance control in supine orientation with and without vision was assessed. Postural control in this test paradigm was hypothesized to utilize predominantly contributions of somatosensory information from the feet and ankle joint, with minimal vestibular input. Fourteen healthy subjects “stood” supine on their dominant leg while strapped to a backpack frame that was freely moving on air-bearings, to remove available otolith tilt cues with respect to gravity that influences postural control when standing upright. The backpack was attached through a cable to a pneumatic cylinder that provided a gravity-like load. Subjects performed three trials each with Eyes-open (EO) and Eyes-closed (EC) while loaded with 60% body weight. There was no difference in unipedal stance time (UST) across the two conditions with EC condition challenging the postural control system greater than the EO condition. Stabilogram-diffusion analysis (SDA) indicated that the critical mean square displacement was significantly different between the two conditions. Vestibular cues, both in terms of magnitude and the duration for which relevant information was available for postural control in this test paradigm, were minimized. These results support our hypothesis that maintaining unipedal stance in supine orientation without vision, minimizes vestibular contribution and thus predominantly utilizes somatosensory information for postural control. PMID:28443004

Spontaneous hair cell regeneration in the mouse utricle following gentamicin ototoxicity.

PubMed

Kawamoto, Kohei; Izumikawa, Masahiko; Beyer, Lisa A; Atkin, Graham M; Raphael, Yehoash

2009-01-01

Whereas most epithelial tissues turn-over and regenerate after a traumatic lesion, this restorative ability is diminished in the sensory epithelia of the inner ear; it is absent in the cochlea and exists only in a limited capacity in the vestibular epithelium. The extent of regeneration in vestibular hair cells has been characterized for several mammalian species including guinea pig, rat, and chinchilla, but not yet in mouse. As the fundamental model species for investigating hereditary disease, the mouse can be studied using a wide variety of genetic and molecular tools. To design a mouse model for vestibular hair cell regeneration research, an aminoglycoside-induced method of complete hair cell elimination was developed in our lab and applied to the murine utricle. Loss of utricular hair cells was observed using scanning electron microscopy, and corroborated by a loss of fluorescent signal in utricles from transgenic mice with GFP-positive hair cells. Regenerative capability was characterized at several time points up to six months following insult. Using scanning electron microscopy, we observed that as early as two weeks after insult, a few immature hair cells, demonstrating the characteristic immature morphology indicative of regeneration, could be seen in the utricle. As time progressed, larger numbers of immature hair cells could be seen along with some mature cells resembling surface morphology of type II hair cells. By six months post-lesion, numerous regenerated hair cells were present in the utricle, however, neither their number nor their appearance was normal. A BrdU assay suggested that at least some of the regeneration of mouse vestibular hair cells involved mitosis. Our results demonstrate that the vestibular sensory epithelium in mice can spontaneously regenerate, elucidate the time course of this process, and identify involvement of mitosis in some cases. These data establish a road map of the murine vestibular regenerative process, which can be used for elucidating the molecular events that govern this process.

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.

Differential Involvement during Latent Herpes Simplex Virus 1 Infection of the Superior and Inferior Divisions of the Vestibular Ganglia: Implications for Vestibular Neuritis

PubMed Central

Lindemann, Anja; Sinicina, Inga; Horn, Anja K. E.; Brandt, Thomas; Strupp, Michael; Hüfner, Katharina

2017-01-01

ABSTRACT Controversy still surrounds both the etiology and pathophysiology of vestibular neuritis (VN). Especially uncertain is why the superior vestibular nerve (SVN) is more frequently affected than the inferior vestibular nerve (IVN), which is partially or totally spared. To address this question, we developed an improved method for preparing human vestibular ganglia (VG) and nerve. Subsequently, macro- and microanatomical as well as PCR studies were performed on 38 human ganglia from 38 individuals. The SVN was 2.4 mm longer than the IVN, and in 65% of the cases, the IVN ran in two separate bony canals, which was not the case for the SVN. Anastomoses between the facial and cochlear nerves were more common for the SVN (14/38 and 9/38, respectively) than for the IVN (7/38 and 2/38, respectively). Using reverse transcription-quantitative PCR (RT-qPCR), we found only a few latently herpes simplex virus 1 (HSV-1)-infected VG (18.4%). In cases of two separate neuronal fields, infected neurons were located in the superior part only. In summary, these PCR and micro- and macroanatomical studies provide possible explanations for the high frequency of SVN infection in vestibular neuritis. IMPORTANCE Vestibular neuritis is known to affect the superior part of the vestibular nerve more frequently than the inferior part. The reason for this clinical phenomenon remains unclear. Anatomical differences may play a role, or if latent HSV-1 infection is assumed, the etiology may be due to the different distribution of the infection. To shed further light on this subject, we conducted different macro- and microanatomical studies. We also assessed the presence of HSV-1 in VG and in different sections of the VG. Our findings add new information on the macro- and microanatomy of the VG as well as the pathophysiology of vestibular neuritis. We also show that latent HSV-1 infection of VG neurons is less frequent than previously reported. PMID:28446678

Differential Involvement during Latent Herpes Simplex Virus 1 Infection of the Superior and Inferior Divisions of the Vestibular Ganglia: Implications for Vestibular Neuritis.

PubMed

Himmelein, Susanne; Lindemann, Anja; Sinicina, Inga; Horn, Anja K E; Brandt, Thomas; Strupp, Michael; Hüfner, Katharina

2017-07-15

Controversy still surrounds both the etiology and pathophysiology of vestibular neuritis (VN). Especially uncertain is why the superior vestibular nerve (SVN) is more frequently affected than the inferior vestibular nerve (IVN), which is partially or totally spared. To address this question, we developed an improved method for preparing human vestibular ganglia (VG) and nerve. Subsequently, macro- and microanatomical as well as PCR studies were performed on 38 human ganglia from 38 individuals. The SVN was 2.4 mm longer than the IVN, and in 65% of the cases, the IVN ran in two separate bony canals, which was not the case for the SVN. Anastomoses between the facial and cochlear nerves were more common for the SVN (14/38 and 9/38, respectively) than for the IVN (7/38 and 2/38, respectively). Using reverse transcription-quantitative PCR (RT-qPCR), we found only a few latently herpes simplex virus 1 (HSV-1)-infected VG (18.4%). In cases of two separate neuronal fields, infected neurons were located in the superior part only. In summary, these PCR and micro- and macroanatomical studies provide possible explanations for the high frequency of SVN infection in vestibular neuritis. IMPORTANCE Vestibular neuritis is known to affect the superior part of the vestibular nerve more frequently than the inferior part. The reason for this clinical phenomenon remains unclear. Anatomical differences may play a role, or if latent HSV-1 infection is assumed, the etiology may be due to the different distribution of the infection. To shed further light on this subject, we conducted different macro- and microanatomical studies. We also assessed the presence of HSV-1 in VG and in different sections of the VG. Our findings add new information on the macro- and microanatomy of the VG as well as the pathophysiology of vestibular neuritis. We also show that latent HSV-1 infection of VG neurons is less frequent than previously reported. Copyright © 2017 American Society for Microbiology.

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.

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.

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.

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.

Reporting success rates in the treatment of vestibular schwannomas: are we accounting for the natural history?

PubMed

Miller, Timothy; Lau, Tsz; Vasan, Rohit; Danner, Christopher; Youssef, A Samy; van Loveren, Harry; Agazzi, Siviero

2014-06-01

Stereotactic radiosurgery is generally accepted as one of the best treatment options for vestibular schwannomas. We question whether growth control is an accurate measure of success in vestibular schwannoma treatment. We aim to clarify the success rate of stereotactic radiosurgery and adjust the reported results to the benign natural history of untreated tumors. All articles were taken from a PubMed search of the English literature from the years 2000-2011. Inclusion criteria were articles containing the number of patients treated, radiation technique, average tumor size, follow-up time, and percentage of tumors growing during follow-up. Data were extracted from 19 articles. Success rates were adjusted using published data that 17% to 30% of vestibular schwannomas grow. The average reported success rate for stereotactic radiosurgery across all articles was 95.5%. When considering 17% or 30% natural growth without intervention, the adjusted success rates became 78.2% and 86.9% respectively. These rates were obtained by applying the natural history growth percentages to any tumors not reported to be growing before radiosurgical intervention. Success in the treatment of vestibular schwannomas with stereotactic radiosurgery is often defined as lack of further growth. Recent data on the natural growth history of vestibular schwannomas raise the question of whether this is the best definition of success. We have identified a lack of continuity regarding the reporting of success and emphasize the importance of the clarification of the success of radiosurgery to make informed decisions regarding the best treatment options for vestibular schwannoma. Copyright © 2014 Elsevier Ltd. All rights reserved.

Treatment of Vestibular Dysfunction Using a Portable Stimulator

DTIC Science & Technology

2017-04-01

AWARD NUMBER: W81XWH-14-2-0012 TITLE: Treatment of Vestibular Dysfunction Using a Portable Stimulator PRINCIPAL INVESTIGATOR: Jorge M...Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time ...Dysfunction Using a Portable Stimulator Email: jorge.serrador@rutgers.edu U U U TABLE OF CONTENTS Page No. INTRODUCTION 4 KEYWORDS 4 ACCOMPLISHMENTS 4

The Nucleus Prepositus Hypoglossi Contributes to Head Direction Cell Stability in Rats

PubMed Central

Butler, William N.

2015-01-01

Head direction (HD) cells in the rat limbic system fire according to the animal's orientation independently of the animal's environmental location or behavior. These HD cells receive strong inputs from the vestibular system, among other areas, as evidenced by disruption of their directional firing after lesions or inactivation of vestibular inputs. Two brainstem nuclei, the supragenual nucleus (SGN) and nucleus prepositus hypoglossi (NPH), are known to project to the HD network and are thought to be possible relays of vestibular information. Previous work has shown that lesioning the SGN leads to a loss of spatial tuning in downstream HD cells, but the NPH has historically been defined as an oculomotor nuclei and therefore its role in contributing to the HD signal is less clear. Here, we investigated this role by recording HD cells in the anterior thalamus after either neurotoxic or electrolytic lesions of the NPH. There was a total loss of direction-specific firing in anterodorsal thalamus cells in animals with complete NPH lesions. However, many cells were identified that fired in bursts unrelated to the animals' directional heading and were similar to cells seen in previous studies that damaged vestibular-associated areas. Some animals with significant but incomplete lesions of the NPH had HD cells that were stable under normal conditions, but were unstable under conditions designed to minimize the use of external cues. These results support the hypothesis that the NPH, beyond its traditional oculomotor function, plays a critical role in conveying vestibular-related information to the HD circuit. PMID:25673848

Vestibular responses in the macaque pedunculopontine nucleus and central mesencephalic reticular formation

PubMed Central

Aravamuthan, Bhooma R.; Angelaki, Dora E.

2012-01-01

The pedunculopontine nucleus (PPN) and central mesencephalic reticular formation (cMRF) both send projections and receive input from areas with known vestibular responses. Noting their connections with the basal ganglia, the locomotor disturbances that occur following lesions of the PPN or cMRF, and the encouraging results of PPN deep brain stimulation in Parkinson’s disease patients, both the PPN and cMRF have been linked to motor control. In order to determine the existence of and characterize vestibular responses in the PPN and cMRF, we recorded single neurons from both structures during vertical and horizontal rotation, translation, and visual pursuit stimuli. The majority of PPN cells (72.5%) were vestibular-only cells that responded exclusively to rotation and translation stimuli but not visual pursuit. Visual pursuit responses were much more prevalent in the cMRF (57.1%) though close to half of cMRF cells were vestibular-only cells (41.1%). Directional preferences also differed between the PPN, which was preferentially modulated during nose-down pitch, and cMRF, which was preferentially modulated during ipsilateral yaw rotation. Finally, amplitude responses were similar between the PPN and cMRF during rotation and pursuit stimuli, but PPN responses to translation were of higher amplitude than cMRF responses. Taken together with their connections to the vestibular circuit, these results implicate the PPN and cMRF in the processing of vestibular stimuli and suggest important roles for both in responding to motion perturbations like falls and turns. PMID:22864184

Kv1 channels and neural processing in vestibular calyx afferents.

PubMed

Meredith, Frances L; Kirk, Matthew E; Rennie, Katherine J

2015-01-01

Potassium-selective ion channels are important for accurate transmission of signals from auditory and vestibular sensory end organs to their targets in the central nervous system. During different gravity conditions, astronauts experience altered input signals from the peripheral vestibular system resulting in sensorimotor dysfunction. Adaptation to altered sensory input occurs, but it is not explicitly known whether this involves synaptic modifications within the vestibular epithelia. Future investigations of such potential plasticity require a better understanding of the electrophysiological mechanisms underlying the known heterogeneity of afferent discharge under normal conditions. This study advances this understanding by examining the role of the Kv1 potassium channel family in mediating action potentials in specialized vestibular afferent calyx endings in the gerbil crista and utricle. Pharmacological agents selective for different sub-types of Kv1 channels were tested on membrane responses in whole cell recordings in the crista. Kv1 channels sensitive to α-dendrotoxin and dendrotoxin-K were found to prevail in the central regions, whereas K(+) channels sensitive to margatoxin, which blocks Kv1.3 and 1.6 channels, were more prominent in peripheral regions. Margatoxin-sensitive currents showed voltage-dependent inactivation. Dendrotoxin-sensitive currents showed no inactivation and dampened excitability in calyces in central neuroepithelial regions. The differential distribution of Kv1 potassium channels in vestibular afferents supports their importance in accurately relaying gravitational and head movement signals through specialized lines to the central nervous system. Pharmacological modulation of specific groups of K(+) channels could help alleviate vestibular dysfunction on earth and in space.

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.

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

Vestibular compensation after vestibular schwannoma surgery: normalization of the subjective visual vertical and disability.

PubMed

Batuecas-Caletrio, Angel; Santacruz-Ruiz, Santiago; Muñoz-Herrera, Angel; Sousa, Pablo; Otero, Alvaro; Perez-Fernandez, Nicolas

2013-05-01

The degree of caloric weakness before surgery influences faster or slower recovery of patients undergoing vestibular schwannoma surgery. The Dizziness Handicap Inventory (DHI) is a good index to show the recovery of patients as it relates directly to an improvement or not of the subjective visual vertical (SVV). To evaluate the process of recovery of patients as measured by the SVV and the DHI after surgical removal of vestibular schwannoma. We studied 24 consecutive patients of the University Hospital of Salamanca who underwent vestibular schwannoma surgery. We assessed age, tumour size, degree of canalicular weakness and preoperative SVV, and their relationship with DHI and SVV at discharge and also at 1, 3 and 6 months postoperatively. Patients with lesser degrees of caloric weakness took longer to normalize SVV than those with a higher caloric weakness before surgery (p < 0.05). There was a significant correlation between DHI and improvements in SVV with time. The differences disappeared in 6 months where all patients, with greater or lesser degree of caloric weakness, had the same results.

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.

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

Processing of proprioceptive and vestibular body signals and self-transcendence in Ashtanga yoga practitioners.

PubMed

Fiori, Francesca; David, Nicole; Aglioti, Salvatore M

2014-01-01

In the rod and frame test (RFT), participants are asked to set a tilted visual linear marker (i.e., a rod), embedded in a square, to the subjective vertical, irrespective of the surrounding frame. People not influenced by the frame tilt are defined as field-independent, while people biased in their rod verticality perception are field-dependent. Performing RFT requires the integration of proprioceptive, vestibular and visual signals with the latter accounting for field-dependency. Studies indicate that motor experts in body-related, balance-improving disciplines tend to be field-independent, i.e., better at verticality perception, suggesting that proprioceptive and vestibular expertise acquired by such exercise may weaken the influence of irrelevant visual signals. What remains unknown is whether the effect of body-related expertise in weighting perceptual information might also be mediated by personality traits, in particular those indexing self-focusing abilities. To explore this issue, we tested field-dependency in a class of body experts, namely yoga practitioners and in non-expert participants. Moreover we explored any link between performance on RFT and self-transcendence (ST), a complex personality construct, which refers to tendency to experience spiritual feelings and ideas. As expected, yoga practitioners (i) were more accurate in assessing the rod's verticality on the RFT, and (ii) expressed significantly higher ST. Interestingly, the performance in these two tests was negatively correlated. More specifically, when asked to provide verticality judgments, highly self-transcendent yoga practitioners were significantly less influenced by a misleading visual context. Our results suggest that being highly self-transcendent may enable yoga practitioners to optimize verticality judgment tasks by relying more on internal (vestibular and proprioceptive) signals coming from their own body, rather than on exteroceptive, visual cues.

Processing of proprioceptive and vestibular body signals and self-transcendence in Ashtanga yoga practitioners

PubMed Central

Fiori, Francesca; David, Nicole; Aglioti, Salvatore M.

2014-01-01

In the rod and frame test (RFT), participants are asked to set a tilted visual linear marker (i.e., a rod), embedded in a square, to the subjective vertical, irrespective of the surrounding frame. People not influenced by the frame tilt are defined as field-independent, while people biased in their rod verticality perception are field-dependent. Performing RFT requires the integration of proprioceptive, vestibular and visual signals with the latter accounting for field-dependency. Studies indicate that motor experts in body-related, balance-improving disciplines tend to be field-independent, i.e., better at verticality perception, suggesting that proprioceptive and vestibular expertise acquired by such exercise may weaken the influence of irrelevant visual signals. What remains unknown is whether the effect of body-related expertise in weighting perceptual information might also be mediated by personality traits, in particular those indexing self-focusing abilities. To explore this issue, we tested field-dependency in a class of body experts, namely yoga practitioners and in non-expert participants. Moreover we explored any link between performance on RFT and self-transcendence (ST), a complex personality construct, which refers to tendency to experience spiritual feelings and ideas. As expected, yoga practitioners (i) were more accurate in assessing the rod's verticality on the RFT, and (ii) expressed significantly higher ST. Interestingly, the performance in these two tests was negatively correlated. More specifically, when asked to provide verticality judgments, highly self-transcendent yoga practitioners were significantly less influenced by a misleading visual context. Our results suggest that being highly self-transcendent may enable yoga practitioners to optimize verticality judgment tasks by relying more on internal (vestibular and proprioceptive) signals coming from their own body, rather than on exteroceptive, visual cues. PMID:25278866

The Frog Vestibular System as a Model for Lesion-Induced Plasticity: Basic Neural Principles and Implications for Posture Control

PubMed Central

Lambert, François M.; Straka, Hans

2011-01-01

Studies of behavioral consequences after unilateral labyrinthectomy have a long tradition in the quest of determining rules and limitations of the central nervous system (CNS) to exert plastic changes that assist the recuperation from the loss of sensory inputs. Frogs were among the first animal models to illustrate general principles of regenerative capacity and reorganizational neural flexibility after a vestibular lesion. The continuous successful use of the latter animals is in part based on the easy access and identifiability of nerve branches to inner ear organs for surgical intervention, the possibility to employ whole brain preparations for in vitro studies and the limited degree of freedom of postural reflexes for quantification of behavioral impairments and subsequent improvements. Major discoveries that increased the knowledge of post-lesional reactive mechanisms in the CNS include alterations in vestibular commissural signal processing and activation of cooperative changes in excitatory and inhibitory inputs to disfacilitated neurons. Moreover, the observed increase of synaptic efficacy in propriospinal circuits illustrates the importance of limb proprioceptive inputs for postural recovery. Accumulated evidence suggests that the lesion-induced neural plasticity is not a goal-directed process that aims toward a meaningful restoration of vestibular reflexes but rather attempts a survival of those neurons that have lost their excitatory inputs. Accordingly, the reaction mechanism causes an improvement of some components but also a deterioration of other aspects as seen by spatio-temporally inappropriate vestibulo-motor responses, similar to the consequences of plasticity processes in various sensory systems and species. The generality of the findings indicate that frogs continue to form a highly amenable vertebrate model system for exploring molecular and physiological events during cellular and network reorganization after a loss of vestibular function. PMID:22518109

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.

Signal processing related to the vestibulo-ocular reflex during combined angular rotation and linear translation of the head

NASA Technical Reports Server (NTRS)

McCrea, R. A.; Chen-Huang, C.; Peterson, B. W. (Principal Investigator)

1999-01-01

The contributions of vestibular nerve afferents and central vestibular pathways to the angular (AVOR) and linear (LVOR) vestibulo-ocular reflex were studied in squirrel monkeys during fixation of near and far targets. Irregular vestibular afferents did not appear to be necessary for the LVOR, since when they were selectively silenced with galvanic currents the LVOR was essentially unaffected during both far- and near-target viewing. The linear translation signals generated by secondary AVOR neurons in the vestibular nuclei were, on average, in phase with head velocity, inversely related to viewing distance, and were nearly as strong as AVOR-related signals. We suggest that spatial-temporal transformation of linear head translation signals to angular eye velocity commands is accomplished primarily by the addition of viewing distance multiplied, centrally integrated, otolith regular afferent signals to angular VOR pathways.

[Static posturography versus clinical tests in elderly people with vestibular pathology].

PubMed

Ortuño-Cortés, Miguel A; Martín-Sanz, Eduardo; Barona-de Guzmán, Rafael

2008-01-01

Balance can be quantified by clinical tests and through instrumental studies. The objective of this paper is to determine the correlation between static posturography and 4 clinical tests of balance in elderly people with vestibular disorders and to identify its capability to discriminate the groups studied. 60 patients with vestibular disorders and 60 healthy subjects performed 4 clinical tests (one leg standing with opened eyes, Timed Up and Go, Tinetti and Berg tests) and a static posturography analysis (NedSVE/IBV system) under 4 conditions: Romberg Test, Eyes Open (REO), Romberg Test, Eyes Closed (REC), Romberg Test on Foam with Eyes Open (RFEO), and Romberg Test on Foam with Eyes Closed (RFEC). RFEO correlated best with the clinical tests and RFEC was the worst. RFEO distinguished between healthy individuals and decompensated patients. RFEO gave the best information about postural balance in the elderly. RFEC was not useful. Static posturography can be useful to distinguish vestibular compensation status.

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.

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

The Vestibular System and Human Dynamic Space Orientation

NASA Technical Reports Server (NTRS)

Meiry, J. L.

1966-01-01

The motion sensors of the vestibular system are studied to determine their role in human dynamic space orientation and manual vehicle control. The investigation yielded control models for the sensors, descriptions of the subsystems for eye stabilization, and demonstrations of the effects of motion cues on closed loop manual control. Experiments on the abilities of subjects to perceive a variety of linear motions provided data on the dynamic characteristics of the otoliths, the linear motion sensors. Angular acceleration threshold measurements supplemented knowledge of the semicircular canals, the angular motion sensors. Mathematical models are presented to describe the known control characteristics of the vestibular sensors, relating subjective perception of motion to objective motion of a vehicle. The vestibular system, the neck rotation proprioceptors and the visual system form part of the control system which maintains the eye stationary relative to a target or a reference. The contribution of each of these systems was identified through experiments involving head and body rotations about a vertical axis. Compensatory eye movements in response to neck rotation were demonstrated and their dynamic characteristics described by a lag-lead model. The eye motions attributable to neck rotations and vestibular stimulation obey superposition when both systems are active. Human operator compensatory tracking is investigated in simple vehicle orientation control system with stable and unstable controlled elements. Control of vehicle orientation to a reference is simulated in three modes: visual, motion and combined. Motion cues sensed by the vestibular system through tactile sensation enable the operator to generate more lead compensation than in fixed base simulation with only visual input. The tracking performance of the human in an unstable control system near the limits of controllability is shown to depend heavily upon the rate information provided by the vestibular sensors.

State-dependent sensorimotor processing: gaze and posture stability during simulated flight in birds.

PubMed

McArthur, Kimberly L; Dickman, J David

2011-04-01

Vestibular responses play an important role in maintaining gaze and posture stability during rotational motion. Previous studies suggest that these responses are state dependent, their expression varying with the environmental and locomotor conditions of the animal. In this study, we simulated an ethologically relevant state in the laboratory to study state-dependent vestibular responses in birds. We used frontal airflow to simulate gliding flight and measured pigeons' eye, head, and tail responses to rotational motion in darkness, under both head-fixed and head-free conditions. We show that both eye and head response gains are significantly higher during flight, thus enhancing gaze and head-in-space stability. We also characterize state-specific tail responses to pitch and roll rotation that would help to maintain body-in-space orientation during flight. These results demonstrate that vestibular sensorimotor processing is not fixed but depends instead on the animal's behavioral state.

State-dependent sensorimotor processing: gaze and posture stability during simulated flight in birds

PubMed Central

McArthur, Kimberly L.

2011-01-01

Vestibular responses play an important role in maintaining gaze and posture stability during rotational motion. Previous studies suggest that these responses are state dependent, their expression varying with the environmental and locomotor conditions of the animal. In this study, we simulated an ethologically relevant state in the laboratory to study state-dependent vestibular responses in birds. We used frontal airflow to simulate gliding flight and measured pigeons′ eye, head, and tail responses to rotational motion in darkness, under both head-fixed and head-free conditions. We show that both eye and head response gains are significantly higher during flight, thus enhancing gaze and head-in-space stability. We also characterize state-specific tail responses to pitch and roll rotation that would help to maintain body-in-space orientation during flight. These results demonstrate that vestibular sensorimotor processing is not fixed but depends instead on the animal's behavioral state. PMID:21307332

MPI CyberMotion Simulator: implementation of a novel motion simulator to investigate multisensory path integration in three dimensions.

PubMed

Barnett-Cowan, Michael; Meilinger, Tobias; Vidal, Manuel; Teufel, Harald; Bülthoff, Heinrich H

2012-05-10

Path integration is a process in which self-motion is integrated over time to obtain an estimate of one's current position relative to a starting point (1). Humans can do path integration based exclusively on visual (2-3), auditory (4), or inertial cues (5). However, with multiple cues present, inertial cues - particularly kinaesthetic - seem to dominate (6-7). In the absence of vision, humans tend to overestimate short distances (<5 m) and turning angles (<30°), but underestimate longer ones (5). Movement through physical space therefore does not seem to be accurately represented by the brain. Extensive work has been done on evaluating path integration in the horizontal plane, but little is known about vertical movement (see (3) for virtual movement from vision alone). One reason for this is that traditional motion simulators have a small range of motion restricted mainly to the horizontal plane. Here we take advantage of a motion simulator (8-9) with a large range of motion to assess whether path integration is similar between horizontal and vertical planes. The relative contributions of inertial and visual cues for path navigation were also assessed. 16 observers sat upright in a seat mounted to the flange of a modified KUKA anthropomorphic robot arm. Sensory information was manipulated by providing visual (optic flow, limited lifetime star field), vestibular-kinaesthetic (passive self motion with eyes closed), or visual and vestibular-kinaesthetic motion cues. Movement trajectories in the horizontal, sagittal and frontal planes consisted of two segment lengths (1st: 0.4 m, 2nd: 1 m; ±0.24 m/s(2) peak acceleration). The angle of the two segments was either 45° or 90°. Observers pointed back to their origin by moving an arrow that was superimposed on an avatar presented on the screen. Observers were more likely to underestimate angle size for movement in the horizontal plane compared to the vertical planes. In the frontal plane observers were more likely to overestimate angle size while there was no such bias in the sagittal plane. Finally, observers responded slower when answering based on vestibular-kinaesthetic information alone. Human path integration based on vestibular-kinaesthetic information alone thus takes longer than when visual information is present. That pointing is consistent with underestimating and overestimating the angle one has moved through in the horizontal and vertical planes respectively, suggests that the neural representation of self-motion through space is non-symmetrical which may relate to the fact that humans experience movement mostly within the horizontal plane.

Requirement for Lmo4 in the Vestibular Morphogenesis of Mouse Inner Ear

PubMed Central

Deng, Min; Pan, Ling; Xie, Xiaoling; Gan, Lin

2009-01-01

During development, compartmentalization of an early embryonic structure produces blocks of cells with distinct properties and developmental potentials. The auditory and vestibular components of vertebrate inner ears are derived from defined compartments within the otocyst during embryogenesis. The vestibular apparatus, including three semicircular canals, saccule, utricle, and their associated sensory organs, detects angular and linear acceleration of the head and relays the information through vestibular neurons to vestibular nuclei in the brainstem. How the early developmental events manifest vestibular structures at the molecular level is largely unknown. Here, we show that LMO4, a LIM-domain-only transcriptional regulator, is required for the formation of semicircular canals and their associated sensory cristae. Targeted disruption of Lmo4 resulted in the dysmorphogenesis of the vestibule and in the absence of three semicircular canals, anterior and posterior cristae. In Lmo4-null otocysts, canal outpouches failed to form and cell proliferation was reduced in the dorsolateral region. Expression analysis of the known otic markers showed that Lmo4 is essential for the normal expression of Bmp4, Fgf10, Msx1, Isl1, Gata3, and Dlx5 in the dorsolateral domain of the otocyst, whereas the initial compartmentalization of the otocyst remains unaffected. Our results demonstrate that Lmo4 controls the development of the dorsolateral otocyst into semicircular canals and cristae through two distinct mechanisms: regulating the expression of otic specific genes and stimulating the proliferation of the dorsolateral part of the otocyst. PMID:19913004

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

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

Vestibular nuclei and cerebellum put visual gravitational motion in context.

PubMed

Miller, William L; Maffei, Vincenzo; Bosco, Gianfranco; Iosa, Marco; Zago, Myrka; Macaluso, Emiliano; Lacquaniti, Francesco

2008-04-01

Animal survival in the forest, and human success on the sports field, often depend on the ability to seize a target on the fly. All bodies fall at the same rate in the gravitational field, but the corresponding retinal motion varies with apparent viewing distance. How then does the brain predict time-to-collision under gravity? A perspective context from natural or pictorial settings might afford accurate predictions of gravity's effects via the recovery of an environmental reference from the scene structure. We report that embedding motion in a pictorial scene facilitates interception of gravitational acceleration over unnatural acceleration, whereas a blank scene eliminates such bias. Functional magnetic resonance imaging (fMRI) revealed blood-oxygen-level-dependent correlates of these visual context effects on gravitational motion processing in the vestibular nuclei and posterior cerebellar vermis. Our results suggest an early stage of integration of high-level visual analysis with gravity-related motion information, which may represent the substrate for perceptual constancy of ubiquitous gravitational motion.

[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.

Gain and phase of perceived virtual rotation evoked by electrical vestibular stimuli

PubMed Central

Peters, Ryan M.; Rasman, Brandon G.; Inglis, J. Timothy

2015-01-01

Galvanic vestibular stimulation (GVS) evokes a perception of rotation; however, very few quantitative data exist on the matter. We performed psychophysical experiments on virtual rotations experienced when binaural bipolar electrical stimulation is applied over the mastoids. We also performed analogous real whole body yaw rotation experiments, allowing us to compare the frequency response of vestibular perception with (real) and without (virtual) natural mechanical stimulation of the semicircular canals. To estimate the gain of vestibular perception, we measured direction discrimination thresholds for virtual and real rotations. Real direction discrimination thresholds decreased at higher frequencies, confirming multiple previous studies. Conversely, virtual direction discrimination thresholds increased at higher frequencies, implying low-pass filtering of the virtual perception process occurring potentially anywhere between afferent transduction and cortical responses. To estimate the phase of vestibular perception, participants manually tracked their perceived position during sinusoidal virtual and real kinetic stimulation. For real rotations, perceived velocity was approximately in phase with actual velocity across all frequencies. Perceived virtual velocity was in phase with the GVS waveform at low frequencies (0.05 and 0.1 Hz). As frequency was increased to 1 Hz, the phase of perceived velocity advanced relative to the GVS waveform. Therefore, at low frequencies GVS is interpreted as an angular velocity signal and at higher frequencies GVS becomes interpreted increasingly as an angular position signal. These estimated gain and phase spectra for vestibular perception are a first step toward generating well-controlled virtual vestibular percepts, an endeavor that may reveal the usefulness of GVS in the areas of clinical assessment, neuroprosthetics, and virtual reality. PMID:25925318

Gain and phase of perceived virtual rotation evoked by electrical vestibular stimuli.

PubMed

Peters, Ryan M; Rasman, Brandon G; Inglis, J Timothy; Blouin, Jean-Sébastien

2015-07-01

Galvanic vestibular stimulation (GVS) evokes a perception of rotation; however, very few quantitative data exist on the matter. We performed psychophysical experiments on virtual rotations experienced when binaural bipolar electrical stimulation is applied over the mastoids. We also performed analogous real whole body yaw rotation experiments, allowing us to compare the frequency response of vestibular perception with (real) and without (virtual) natural mechanical stimulation of the semicircular canals. To estimate the gain of vestibular perception, we measured direction discrimination thresholds for virtual and real rotations. Real direction discrimination thresholds decreased at higher frequencies, confirming multiple previous studies. Conversely, virtual direction discrimination thresholds increased at higher frequencies, implying low-pass filtering of the virtual perception process occurring potentially anywhere between afferent transduction and cortical responses. To estimate the phase of vestibular perception, participants manually tracked their perceived position during sinusoidal virtual and real kinetic stimulation. For real rotations, perceived velocity was approximately in phase with actual velocity across all frequencies. Perceived virtual velocity was in phase with the GVS waveform at low frequencies (0.05 and 0.1 Hz). As frequency was increased to 1 Hz, the phase of perceived velocity advanced relative to the GVS waveform. Therefore, at low frequencies GVS is interpreted as an angular velocity signal and at higher frequencies GVS becomes interpreted increasingly as an angular position signal. These estimated gain and phase spectra for vestibular perception are a first step toward generating well-controlled virtual vestibular percepts, an endeavor that may reveal the usefulness of GVS in the areas of clinical assessment, neuroprosthetics, and virtual reality. Copyright © 2015 the American Physiological Society.

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.

Long-lasting effects of neck muscle vibration and contraction on self-motion perception of vestibular origin.

PubMed

Pettorossi, Vito Enrico; Panichi, Roberto; Botti, Fabio Massimo; Biscarini, Andrea; Filippi, Guido Maria; Schieppati, Marco

2015-10-01

To show that neck proprioceptive input can induce long-term effects on vestibular-dependent self-motion perception. Motion perception was assessed by measuring the subject's error in tracking in the dark the remembered position of a fixed target during whole-body yaw asymmetric rotation of a supporting platform, consisting in a fast rightward half-cycle and a slow leftward half-cycle returning the subject to the initial position. Neck muscles were relaxed or voluntarily contracted, and/or vibrated. Whole-body rotation was administered during or at various intervals after the vibration train. The tracking position error (TPE) at the end of the platform rotation was measured during and after the muscle conditioning maneuvers. Neck input produced immediate and sustained changes in the vestibular perceptual response to whole-body rotation. Vibration of the left sterno-cleido-mastoideus (SCM) or right splenius capitis (SC) or isometric neck muscle effort to rotate the head to the right enhanced the TPE by decreasing the perception of the slow rotation. The reverse effect was observed by activating the contralateral muscle. The effects persisted after the end of SCM conditioning, and slowly vanished within several hours, as tested by late asymmetric rotations. The aftereffect increased in amplitude and persistence by extending the duration of the vibration train (from 1 to 10min), augmenting the vibration frequency (from 5 to 100Hz) or contracting the vibrated muscle. Symmetric yaw rotation elicited a negligible TPE, upon which neck muscle vibrations were ineffective. Neck proprioceptive input induces enduring changes in vestibular-dependent self-motion perception, conditional on the vestibular stimulus feature, and on the side and the characteristics of vibration and status of vibrated muscles. This shows that our perception of whole-body yaw-rotation is not only dependent on accurate vestibular information, but is modulated by proprioceptive information related to previously experienced position of head with respect to trunk. Tonic proprioceptive inflow, as might occur as a consequence of enduring or permanent head postures, can induce adaptive plastic changes in vestibular-dependent motion sensitiveness. These changes might be counteracted by vibration of selected neck muscles. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

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.;

Current concepts and future approaches to vestibular rehabilitation.

PubMed

Tjernström, Fredrik; Zur, Oz; Jahn, Klaus

2016-04-01

Over the last decades methods of vestibular rehabilitation to enhance adaptation to vestibular loss, habituation to changing sensory conditions, and sensory reweighting in the compensation process have been developed. However, the use of these techniques still depends to a large part on the educational background of the therapist. Individualized assessment of deficits and specific therapeutic programs for different disorders are sparse. Currently, vestibular rehabilitation is often used in an unspecific way in dizzy patients irrespective of the clinical findings. When predicting the future of vestibular rehabilitation, it is tempting to foretell advances in technology for assessment and treatment only, but the current intense exchange between clinicians and basic scientists also predicts advances in truly understanding the complex interactions between the peripheral senses and central adaptation mechanisms. More research is needed to develop reliable techniques to measure sensory dependence and to learn how this knowledge can be best used--by playing off the patient's sensory strength or working on the weakness. To be able using the emerging concepts, the neuro-otological community must strive to educate physicians, physiotherapists and nurses to perform the correct examinations for assessment of individual deficits and to look for factors that might impede rehabilitation.

Active and passive spatial learning in human navigation: acquisition of survey knowledge.

PubMed

Chrastil, Elizabeth R; Warren, William H

2013-09-01

It seems intuitively obvious that active exploration of a new environment would lead to better spatial learning than would passive visual exposure. It is unclear, however, which components of active learning contribute to spatial knowledge, and previous literature is decidedly mixed. This experiment tests the contributions of 4 components to metric survey knowledge: visual, vestibular, and podokinetic information and cognitive decision making. In the learning phase, 6 groups of participants learned the locations of 8 objects in a virtual hedge maze by (a) walking, (b) being pushed in a wheelchair, or (c) watching a video, crossed with (1) making decisions about their path or (2) being guided through the maze. In the test phase, survey knowledge was assessed by having participants walk a novel shortcut from a starting object to the remembered location of a test object, with the maze removed. Performance was slightly better than chance in the passive video condition. The addition of vestibular information did not improve performance in the wheelchair condition, but the addition of podokinetic information significantly improved angular accuracy in the walking condition. In contrast, there was no effect of decision making in any condition. The results indicate that visual and podokinetic information significantly contribute to survey knowledge, whereas vestibular information and decision making do not. We conclude that podokinetic information is the primary component of active learning for the acquisition of metric survey knowledge. PsycINFO Database Record (c) 2013 APA, all rights reserved.

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.

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.

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.

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.

Disequilibrium After Traumatic Brain Injury: Vestibular Mechanisms

DTIC Science & Technology

2011-09-01

of otolith signal processing, including the integration of head acceleration26 and the disambiguation of linear ac- celeration signals related to tilt ...Foveal versus full-field visual stabilization strategies for translational and rotational head movements. J. Neurosci. 23: 1104–1108. 14. Walker, M.F., M...in the vestibular reflexes that compensate for linear movements of the head and body during standing and walking. The experimental protocol has two

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.

Source analysis of short and long latency vestibular-evoked potentials (VsEPs) produced by left vs. right ear air-conducted 500 Hz tone pips.

PubMed

Todd, N P M; Paillard, A C; Kluk, K; Whittle, E; Colebatch, J G

2014-06-01

Todd et al. (2014) have recently demonstrated the presence of vestibular dependent changes both in the morphology and in the intensity dependence of auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs). In this paper we extend this work by comparing left vs. right ear stimulation and by conducting a source analysis of the resulting evoked potentials of short and long latency. Ten healthy, right-handed subjects were recruited and evoked potentials were recorded to both left- and right-ear sound stimulation, above and below vestibular threshold. Below VEMP threshold, typical AEPs were recorded, consisting of mid-latency (MLR) waves Na and Pa followed by long latency AEPs (LAEPs) N1 and P2. In the supra-threshold condition, the expected changes in morphology were observed, consisting of: (1) short-latency vestibular evoked potentials (VsEPs) which have no auditory correlate, i.e. the ocular VEMP (OVEMP) and inion response related potentials; (2) a later deflection, labelled N42/P52, followed by the LAEPs N1 and P2. Statistical analysis of the vestibular dependent responses indicated a contralateral effect for inion related short-latency responses and a left-ear/right-hemisphere advantage for the long-latency responses. Source analysis indicated that the short-latency effects may be mediated by a contralateral projection to left cerebellum, while the long-latency effects were mediated by a contralateral projection to right cingulate cortex. In addition we found evidence of a possible vestibular contribution to the auditory T-complex in radial temporal lobe sources. These last results raise the possibility that acoustic activation of the otolith organs could potentially contribute to auditory processing. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Stability of controlled inverted pendulum under permanent horizontal perturbations of the supporting point

NASA Astrophysics Data System (ADS)

Aleksandrov, V. V.; Reyes-Romero, M.; Sidorenko, G. Yu.; Temoltzi-Auila, R.

2010-04-01

We consider the problem of choosing a test perturbation of a movable foundation of a single-link inverted pendulum so as to test a vestibular prosthesis prototype located at the top of this pendulum in an extreme situation. The obtained results permit concluding that the information transmitted from otolithic organs of the human vestibular system to muscles of the locomotor apparatus is very important and improves the quality of stabilization of the human vertical posture preventing the possible fall.

Understanding How Astronauts Adapt to Space and to Earth: Anatomical Studies of Central Vestibular Adaptation

NASA Technical Reports Server (NTRS)

Holstein, Gay; Vasques, Marilyn; Aquilina, Rudy (Technical Monitor)

2002-01-01

Significant changes take place in the nervous systems of astronauts during and following exposure to microgravity. These changes, particularly in the part of the brain that controls balance, the vestibular system, can cause sensations of rotation, dizziness, and vertigo, as well as space adaptation syndrome. Adaptation to the microgravity environment usually occurs within one week, and a subsequent re-adaptation period of several days is often required upon return to Earth. In order to realize long-term spaceflight, effective countermeasures for these symptoms must be developed. The structural changes that take place in one of the vestibular regions of the brain (the cerebellar cortex) during the process of adaptation to Earth's gravity remain unclear and are the subject of an experiment being conducted on STS-107 by Dr. Gay Holstein of the Mount Sinai School of Medicine in New York. Using the rat as a model, Dr. Holstein and her team will seek to identify the cellular changes underlying the vestibular changes experienced by astronauts.

Perception of tilt and ocular torsion of vestibular patients during eccentric rotation.

PubMed

Clément, Gilles; Deguine, Olivier

2010-01-04

Four patients following unilateral vestibular loss and four patients complaining of otolith-dependent vertigo were tested during eccentric yaw rotation generating 1 x g centripetal acceleration directed along the interaural axis. Perception of body tilt in roll and in pitch was recorded in darkness using a somatosensory plate that the subjects maintained parallel to the perceived horizon. Ocular torsion was recorded by a video camera. Unilateral vestibular-defective patients underestimated the magnitude of the roll tilt and had a smaller torsion when the centrifugal force was towards the operated ear compared to the intact ear and healthy subjects. Patients with otolithic-dependent vertigo overestimated the magnitude of roll tilt in both directions of eccentric rotation relative to healthy subjects, and their ocular torsion was smaller than in healthy subjects. Eccentric rotation is a promising tool for the evaluation of vestibular dysfunction in patients. Eye torsion and perception of tilt during this stimulation are objective and subjective measurements, which could be used to determine alterations in spatial processing in the CNS.

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

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.

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.

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.

Comparative analysis of pharmacological treatments with N-acetyl-DL-leucine (Tanganil) and its two isomers (N-acetyl-L-leucine and N-acetyl-D-leucine) on vestibular compensation: Behavioral investigation in the cat.

PubMed

Tighilet, Brahim; Leonard, Jacques; Bernard-Demanze, Laurence; Lacour, Michel

2015-12-15

Head roll tilt, postural imbalance and spontaneous nystagmus are the main static vestibular deficits observed after an acute unilateral vestibular loss (UVL). In the UVL cat model, these deficits are fully compensated over 6 weeks as the result of central vestibular compensation. N-Acetyl-dl-leucine is a drug prescribed in clinical practice for the symptomatic treatment of acute UVL patients. The present study investigated the effects of N-acetyl-dl-leucine on the behavioral recovery after unilateral vestibular neurectomy (UVN) in the cat, and compared the effects of each of its two isomers N-acetyl-L-leucine and N-acetyl-D-leucine. Efficacy of these three drug treatments has been evaluated with respect to a placebo group (UVN+saline water) on the global sensorimotor activity (observation grids), the posture control (support surface measurement), the locomotor balance (maximum performance at the rotating beam test), and the spontaneous vestibular nystagmus (recorded in the light). Whatever the parameters tested, the behavioral recovery was strongly and significantly accelerated under pharmacological treatments with N-acetyl-dl-leucine and N-acetyl-L-leucine. In contrast, the N-acetyl-D-leucine isomer had no effect at all on the behavioral recovery, and animals of this group showed the same recovery profile as those receiving a placebo. It is concluded that the N-acetyl-L-leucine isomer is the active part of the racemate component since it induces a significant acceleration of the vestibular compensation process similar (and even better) to that observed under treatment with the racemate component only. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

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.

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.

Compensation Following Bilateral Vestibular Damage

PubMed Central

McCall, Andrew A.; Yates, Bill J.

2011-01-01

Bilateral loss of vestibular inputs affects far fewer patients than unilateral inner ear damage, and thus has been understudied. In both animal subjects and human patients, bilateral vestibular hypofunction (BVH) produces a variety of clinical problems, including impaired balance control, inability to maintain stable blood pressure during postural changes, difficulty in visual targeting of images, and disturbances in spatial memory and navigational performance. Experiments in animals have shown that non-labyrinthine inputs to the vestibular nuclei are rapidly amplified following the onset of BVH, which may explain the recovery of postural stability and orthostatic tolerance that occurs within 10 days. However, the loss of the vestibulo-ocular reflex and degraded spatial cognition appear to be permanent in animals with BVH. Current concepts of the compensatory mechanisms in humans with BVH are largely inferential, as there is a lack of data from patients early in the disease process. Translation of animal studies of compensation for BVH into therapeutic strategies and subsequent application in the clinic is the most likely route to improve treatment. In addition to physical therapy, two types of prosthetic devices have been proposed to treat individuals with bilateral loss of vestibular inputs: those that provide tactile stimulation to indicate body position in space, and those that deliver electrical stimuli to branches of the vestibular nerve in accordance with head movements. The relative efficacy of these two treatment paradigms, and whether they can be combined to facilitate recovery, is yet to be ascertained. PMID:22207864

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

Synaptic plasticity in the medial vestibular nuclei: role of glutamate receptors and retrograde messengers in rat brainstem slices.

PubMed

Grassi, S; Pettorossi, V E

2001-08-01

The analysis of cellular-molecular events mediating synaptic plasticity within vestibular nuclei is an attempt to explain the mechanisms underlying vestibular plasticity phenomena. The present review is meant to illustrate the main results, obtained in vitro, on the mechanisms underlying long-term changes in synaptic strength within the medial vestibular nuclei. The synaptic plasticity phenomena taking place at the level of vestibular nuclei could be useful for adapting and consolidating the efficacy of vestibular neuron responsiveness to environmental requirements, as during visuo-vestibular recalibration and vestibular compensation. Following a general introduction on the most salient features of vestibular compensation and visuo-vestibular adaptation, which are two plastic events involving neuronal circuitry within the medial vestibular nuclei, the second and third sections describe the results from rat brainstem slice studies, demonstrating the possibility to induce long-term potentiation and depression in the medial vestibular nuclei, following high frequency stimulation of the primary vestibular afferents. In particular the mechanisms sustaining the induction and expression of vestibular long-term potentiation and depression, such as the role of various glutamate receptors and retrograde messengers have been described. The relevant role of the interaction between the platelet-activating factor, acting as a retrograde messenger, and the presynaptic metabotropic glutamate receptors, in determining the full expression of vestibular long-term potentiation is also underlined. In addition, the mechanisms involved in vestibular long-term potentiation have been compared with those leading to long-term potentiation in the hippocampus to emphasize the most significant differences emerging from vestibular studies. The fourth part, describes recent results demonstrating the essential role of nitric oxide, another retrograde messenger, in the induction of vestibular potentiation. Finally the fifth part suggests the possible functional significance of different action times of the two retrograde messengers and metabotropic glutamate receptors, which are involved in mediating the presynaptic mechanism sustaining vestibular long-term potentiation.

Sensorimotor aspects of high-speed artificial gravity: I. Sensory conflict in vestibular adaptation

NASA Technical Reports Server (NTRS)

Brown, Erika L.; Hecht, Heiko; Young, Laurence R.

2002-01-01

Short-radius centrifugation offers a promising and affordable countermeasure to the adverse effects of prolonged weightlessness. However, head movements made in a fast rotating environment elicit Coriolis effects, which seriously compromise sensory and motor processes. We found that participants can adapt to these Coriolis effects when exposed intermittently to high rotation rates and, at the same time, can maintain their perceptual-motor coordination in stationary environments. In this paper, we explore the role of inter-sensory conflict in this adaptation process. Different measures (vertical nystagmus, illusory body tilt, motion sickness) react differently to visual-vestibular conflict and adapt differently. In particular, proprioceptive-vestibular conflict sufficed to adapt subjective parameters and the time constant of nystagmus decay, while retinal slip was required for VOR gain adaptation. A simple correlation between the strength of intersensory conflict and the efficacy of adaptation fails to explain the data. Implications of these findings, which differ from existing data for low rotation rates, are discussed.

Model of human dynamic orientation. Ph.D. Thesis; [associated with vestibular stimuli

NASA Technical Reports Server (NTRS)

Ormsby, C. C.

1974-01-01

The dynamics associated with the perception of orientation were modelled for near-threshold and suprathreshold vestibular stimuli. A model of the information available at the peripheral sensors which was consistent with available neurophysiologic data was developed and served as the basis for the models of the perceptual responses. The central processor was assumed to utilize the information from the peripheral sensors in an optimal (minimum mean square error) manner to produce the perceptual estimates of dynamic orientation. This assumption, coupled with the models of sensory information, determined the form of the model for the central processor. The problem of integrating information from the semi-circular canals and the otoliths to predict the perceptual response to motions which stimulated both organs was studied. A model was developed which was shown to be useful in predicting the perceptual response to multi-sensory stimuli.

Morphological evidence for local microcircuits in rat vestibular maculae

NASA Technical Reports Server (NTRS)

Ross, M. D.

1997-01-01

Previous studies suggested that intramacular, unmyelinated segments of vestibular afferent nerve fibers and their large afferent endings (calyces) on type I hair cells branch. Many of the branches (processes) contain vesicles and are presynaptic to type II hair cells, other processes, intramacular nerve fibers, and calyces. This study used serial section transmission electron microscopy and three-dimensional reconstruction methods to document the origins and distributions of presynaptic processes of afferents in the medial part of the adult rat utricular macula. The ultrastructural research focused on presynaptic processes whose origin and termination could be observed in a single micrograph. Results showed that calyces had 1) vesiculated, spine-like processes that invaginated type I cells and 2) other, elongate processes that ended on type II cells pre- as well as postsynaptically. Intramacular, unmyelinated segments of afferent nerve fibers gave origin to branches that were presynaptic to type II cells, calyces, calyceal processes, and other nerve fibers in the macula. Synapses with type II cells occurred opposite subsynaptic cisternae (C synapses); all other synapses were asymmetric. Vesicles were pleomorphic but were differentially distributed according to process origin. Small, clear-centered vesicles, approximately 40-60 nm in diameter, predominated in processes originating from afferent nerve fibers and basal parts of calyces. Larger vesicles approximately 70-120 nm in diameter having approximately 40-80 nm electron-opaque cores were dominant in processes originating from the necks of calyces. Results are interpreted to indicate the existence of a complex system of intrinsic feedforward (postsynaptic)-feedback (presynaptic) connections in a network of direct and local microcircuits. The morphological findings support the concept that maculae dynamically preprocess linear acceleratory information before its transmission to the central nervous system.

Towards a neuromorphic vestibular system.

PubMed

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

2014-10-01

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

Improving Early Adaptation Following Long Duration Spaceflight by Enhancing Vestibular Information

NASA Technical Reports Server (NTRS)

Mulavara, Ajitkumar; Kofman, Igor; DeDios, Yiri E.; Galvan, Raquel; Miller, Chris; Peters, Brian; Cohen, Helen; Jeevarajan, Jerome; Reschke, Millard; Wood, Scott;

Motor Performance is Impaired Following Vestibular Stimulation in Ageing Mice

PubMed Central

Tung, Victoria W. K.; Burton, Thomas J.; Quail, Stephanie L.; Mathews, Miranda A.; Camp, Aaron J.

2016-01-01

Balance and maintaining postural equilibrium are important during stationary and dynamic movements to prevent falls, particularly in older adults. While our sense of balance is influenced by vestibular, proprioceptive, and visual information, this study focuses primarily on the vestibular component and its age-related effects on balance. C57Bl/6J mice of ages 1, 5–6, 8–9 and 27–28 months were tested using a combination of standard (such as grip strength and rotarod) and newly-developed behavioral tests (including balance beam and walking trajectory tests with a vestibular stimulus). In the current study, we confirm a decline in fore-limb grip strength and gross motor coordination as age increases. We also show that a vestibular stimulus of low frequency (2–3 Hz) and duration can lead to age-dependent changes in balance beam performance, which was evident by increases in latency to begin walking on the beam as well as the number of times hind-feet slip (FS) from the beam. Furthermore, aged mice (27–28 months) that received continuous access to a running wheel for 4 weeks did not improve when retested. Mice of ages 1, 10, 13 and 27–28 months were also tested for changes in walking trajectory as a result of the vestibular stimulus. While no linear relationship was observed between the changes in trajectory and age, 1-month-old mice were considerably less affected than mice of ages 10, 13 and 27–28 months. Conclusion: this study confirms there are age-related declines in grip strength and gross motor coordination. We also demonstrate age-dependent changes to finer motor abilities as a result of a low frequency and duration vestibular stimulus. These changes showed that while the ability to perform the balance beam task remained intact across all ages tested, behavioral changes in task performance were observed. PMID:26869921

Motor Performance is Impaired Following Vestibular Stimulation in Ageing Mice.

PubMed

Tung, Victoria W K; Burton, Thomas J; Quail, Stephanie L; Mathews, Miranda A; Camp, Aaron J

2016-01-01

Balance and maintaining postural equilibrium are important during stationary and dynamic movements to prevent falls, particularly in older adults. While our sense of balance is influenced by vestibular, proprioceptive, and visual information, this study focuses primarily on the vestibular component and its age-related effects on balance. C57Bl/6J mice of ages 1, 5-6, 8-9 and 27-28 months were tested using a combination of standard (such as grip strength and rotarod) and newly-developed behavioral tests (including balance beam and walking trajectory tests with a vestibular stimulus). In the current study, we confirm a decline in fore-limb grip strength and gross motor coordination as age increases. We also show that a vestibular stimulus of low frequency (2-3 Hz) and duration can lead to age-dependent changes in balance beam performance, which was evident by increases in latency to begin walking on the beam as well as the number of times hind-feet slip (FS) from the beam. Furthermore, aged mice (27-28 months) that received continuous access to a running wheel for 4 weeks did not improve when retested. Mice of ages 1, 10, 13 and 27-28 months were also tested for changes in walking trajectory as a result of the vestibular stimulus. While no linear relationship was observed between the changes in trajectory and age, 1-month-old mice were considerably less affected than mice of ages 10, 13 and 27-28 months. this study confirms there are age-related declines in grip strength and gross motor coordination. We also demonstrate age-dependent changes to finer motor abilities as a result of a low frequency and duration vestibular stimulus. These changes showed that while the ability to perform the balance beam task remained intact across all ages tested, behavioral changes in task performance were observed.

Perceived state of self during motion can differentially modulate numerical magnitude allocation.

PubMed

Arshad, Q; Nigmatullina, Y; Roberts, R E; Goga, U; Pikovsky, M; Khan, S; Lobo, R; Flury, A-S; Pettorossi, V E; Cohen-Kadosh, R; Malhotra, P A; Bronstein, A M

2016-09-01

Although a direct relationship between numerical allocation and spatial attention has been proposed, recent research suggests that these processes are not directly coupled. In keeping with this, spatial attention shifts induced either via visual or vestibular motion can modulate numerical allocation in some circumstances but not in others. In addition to shifting spatial attention, visual or vestibular motion paradigms also (i) elicit compensatory eye movements which themselves can influence numerical processing and (ii) alter the perceptual state of 'self', inducing changes in bodily self-consciousness impacting upon cognitive mechanisms. Thus, the precise mechanism by which motion modulates numerical allocation remains unknown. We sought to investigate the influence that different perceptual experiences of motion have upon numerical magnitude allocation while controlling for both eye movements and task-related effects. We first used optokinetic visual motion stimulation (OKS) to elicit the perceptual experience of either 'visual world' or 'self'-motion during which eye movements were identical. In a second experiment, we used a vestibular protocol examining the effects of perceived and subliminal angular rotations in darkness, which also provoked identical eye movements. We observed that during the perceptual experience of 'visual world' motion, rightward OKS-biased judgments towards smaller numbers, whereas leftward OKS-biased judgments towards larger numbers. During the perceptual experience of 'self-motion', judgments were biased towards larger numbers irrespective of the OKS direction. Contrastingly, vestibular motion perception was found not to modulate numerical magnitude allocation, nor was there any differential modulation when comparing 'perceived' vs. 'subliminal' rotations. We provide a novel demonstration that numerical magnitude allocation can be differentially modulated by the perceptual state of self during visual but not vestibular mediated motion. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

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.

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.

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.

Decentralized Multisensory Information Integration in Neural Systems.

PubMed

Zhang, Wen-Hao; Chen, Aihua; Rasch, Malte J; Wu, Si

2016-01-13

How multiple sensory cues are integrated in neural circuitry remains a challenge. The common hypothesis is that information integration might be accomplished in a dedicated multisensory integration area receiving feedforward inputs from the modalities. However, recent experimental evidence suggests that it is not a single multisensory brain area, but rather many multisensory brain areas that are simultaneously involved in the integration of information. Why many mutually connected areas should be needed for information integration is puzzling. Here, we investigated theoretically how information integration could be achieved in a distributed fashion within a network of interconnected multisensory areas. Using biologically realistic neural network models, we developed a decentralized information integration system that comprises multiple interconnected integration areas. Studying an example of combining visual and vestibular cues to infer heading direction, we show that such a decentralized system is in good agreement with anatomical evidence and experimental observations. In particular, we show that this decentralized system can integrate information optimally. The decentralized system predicts that optimally integrated information should emerge locally from the dynamics of the communication between brain areas and sheds new light on the interpretation of the connectivity between multisensory brain areas. To extract information reliably from ambiguous environments, the brain integrates multiple sensory cues, which provide different aspects of information about the same entity of interest. Here, we propose a decentralized architecture for multisensory integration. In such a system, no processor is in the center of the network topology and information integration is achieved in a distributed manner through reciprocally connected local processors. Through studying the inference of heading direction with visual and vestibular cues, we show that the decentralized system can integrate information optimally, with the reciprocal connections between processers determining the extent of cue integration. Our model reproduces known multisensory integration behaviors observed in experiments and sheds new light on our understanding of how information is integrated in the brain. Copyright © 2016 Zhang et al.

Decentralized Multisensory Information Integration in Neural Systems

PubMed Central

Zhang, Wen-hao; Chen, Aihua

2016-01-01

How multiple sensory cues are integrated in neural circuitry remains a challenge. The common hypothesis is that information integration might be accomplished in a dedicated multisensory integration area receiving feedforward inputs from the modalities. However, recent experimental evidence suggests that it is not a single multisensory brain area, but rather many multisensory brain areas that are simultaneously involved in the integration of information. Why many mutually connected areas should be needed for information integration is puzzling. Here, we investigated theoretically how information integration could be achieved in a distributed fashion within a network of interconnected multisensory areas. Using biologically realistic neural network models, we developed a decentralized information integration system that comprises multiple interconnected integration areas. Studying an example of combining visual and vestibular cues to infer heading direction, we show that such a decentralized system is in good agreement with anatomical evidence and experimental observations. In particular, we show that this decentralized system can integrate information optimally. The decentralized system predicts that optimally integrated information should emerge locally from the dynamics of the communication between brain areas and sheds new light on the interpretation of the connectivity between multisensory brain areas. SIGNIFICANCE STATEMENT To extract information reliably from ambiguous environments, the brain integrates multiple sensory cues, which provide different aspects of information about the same entity of interest. Here, we propose a decentralized architecture for multisensory integration. In such a system, no processor is in the center of the network topology and information integration is achieved in a distributed manner through reciprocally connected local processors. Through studying the inference of heading direction with visual and vestibular cues, we show that the decentralized system can integrate information optimally, with the reciprocal connections between processers determining the extent of cue integration. Our model reproduces known multisensory integration behaviors observed in experiments and sheds new light on our understanding of how information is integrated in the brain. PMID:26758843

Activation Changes in Zebra Finch (Taeniopygia guttata) Brain Areas Evoked by Alterations of the Earth Magnetic Field

PubMed Central

Keary, Nina; Bischof, Hans-Joachim

2012-01-01

Many animals are able to perceive the earth magnetic field and to use it for orientation and navigation within the environment. The mechanisms underlying the perception and processing of magnetic field information within the brain have been thoroughly studied, especially in birds, but are still obscure. Three hypotheses are currently discussed, dealing with ferromagnetic particles in the beak of birds, with the same sort of particles within the lagena organs, or describing magnetically influenced radical-pair processes within retinal photopigments. Each hypothesis is related to a well-known sensory organ and claims parallel processing of magnetic field information with somatosensory, vestibular and visual input, respectively. Changes in activation within nuclei of the respective sensory systems have been shown previously. Most of these previous experiments employed intensity enhanced magnetic stimuli or lesions. We here exposed unrestrained zebra finches to either a stationary or a rotating magnetic field of the local intensity and inclination. C-Fos was used as an activity marker to examine whether the two treatments led to differences in fourteen brain areas including nuclei of the somatosensory, vestibular and visual system. An ANOVA revealed an overall effect of treatment, indicating that the magnetic field change was perceived by the birds. While the differences were too small to be significant in most areas, a significant enhancement of activation by the rotating stimulus was found in a hippocampal subdivision. Part of the hyperpallium showed a strong, nearly significant, increase. Our results are compatible with previous studies demonstrating an involvement of at least three different sensory systems in earth magnetic field perception and suggest that these systems, probably less elaborated, may also be found in nonmigrating birds. PMID:22679515

Activation changes in zebra finch (Taeniopygia guttata) brain areas evoked by alterations of the earth magnetic field.

PubMed

Keary, Nina; Bischof, Hans-Joachim

2012-01-01

Many animals are able to perceive the earth magnetic field and to use it for orientation and navigation within the environment. The mechanisms underlying the perception and processing of magnetic field information within the brain have been thoroughly studied, especially in birds, but are still obscure. Three hypotheses are currently discussed, dealing with ferromagnetic particles in the beak of birds, with the same sort of particles within the lagena organs, or describing magnetically influenced radical-pair processes within retinal photopigments. Each hypothesis is related to a well-known sensory organ and claims parallel processing of magnetic field information with somatosensory, vestibular and visual input, respectively. Changes in activation within nuclei of the respective sensory systems have been shown previously. Most of these previous experiments employed intensity enhanced magnetic stimuli or lesions. We here exposed unrestrained zebra finches to either a stationary or a rotating magnetic field of the local intensity and inclination. C-Fos was used as an activity marker to examine whether the two treatments led to differences in fourteen brain areas including nuclei of the somatosensory, vestibular and visual system. An ANOVA revealed an overall effect of treatment, indicating that the magnetic field change was perceived by the birds. While the differences were too small to be significant in most areas, a significant enhancement of activation by the rotating stimulus was found in a hippocampal subdivision. Part of the hyperpallium showed a strong, nearly significant, increase. Our results are compatible with previous studies demonstrating an involvement of at least three different sensory systems in earth magnetic field perception and suggest that these systems, probably less elaborated, may also be found in nonmigrating birds.

Alignment of angular velocity sensors for a vestibular prosthesis.

PubMed

Digiovanna, Jack; Carpaneto, Jacopo; Micera, Silvestro; Merfeld, Daniel M

2012-02-13

Vestibular prosthetics transmit angular velocities to the nervous system via electrical stimulation. Head-fixed gyroscopes measure angular motion, but the gyroscope coordinate system will not be coincident with the sensory organs the prosthetic replaces. Here we show a simple calibration method to align gyroscope measurements with the anatomical coordinate system. We benchmarked the method with simulated movements and obtain proof-of-concept with one healthy subject. The method was robust to misalignment, required little data, and minimal processing.

Characterization of slow and fast phase nystagmus

NASA Technical Reports Server (NTRS)

Lessard, Charles S.; Rodriguez-Garcia, Carlos A.; Wong, Wing Chan; Im, Jae J.; Schmidt, Glenn F.

1991-01-01

A current literature review of the analog and digital process of vestibular and optical kinetic nystagmus reveals little agreement in the methods used by various labs. The strategies for detection of saccade (fast phase velocity component of nystagmus) vary between labs, and most of the process have not been evaluated and validated with a standard database. A survey was made of major vestibular labs in the U.S. that perform computer analyses of vestibular and optokinetic reflexes to stimuli, and a baseline was established from which to standardize data acquisition and analysis programs. The concept of an Error Index was employed as the criterium for evaluating the performance of the vestibular analysis software programs. The performance criterium is based on the detection of saccades and is the average of the percentages of missed detections and false detections. Evaluation of the programs produced results for lateral gaze with saccadic amplitude of one, two, three, five, and ten degrees with various signal-to-noise ratios. In addition, results were obtained for sinusoidal pursuit of 0.05, 0.10, and 0.50 Hz with saccades from one to ten degrees at various signal-to-noise ratios. Selection of the best program was made from the performance in the lateral gaze with three degrees of saccadic amplitude and in the 0.10 Hz sinusoid with three degrees of saccadic amplitude.

Vestibular responses in the macaque pedunculopontine nucleus and central mesencephalic reticular formation.

PubMed

Aravamuthan, B R; Angelaki, D E

2012-10-25

The pedunculopontine nucleus (PPN) and central mesencephalic reticular formation (cMRF) both send projections and receive input from areas with known vestibular responses. Noting their connections with the basal ganglia, the locomotor disturbances that occur following lesions of the PPN or cMRF, and the encouraging results of PPN deep brain stimulation in Parkinson's disease patients, both the PPN and cMRF have been linked to motor control. In order to determine the existence of and characterize vestibular responses in the PPN and cMRF, we recorded single neurons from both structures during vertical and horizontal rotation, translation, and visual pursuit stimuli. The majority of PPN cells (72.5%) were vestibular-only (VO) cells that responded exclusively to rotation and translation stimuli but not visual pursuit. Visual pursuit responses were much more prevalent in the cMRF (57.1%) though close to half of cMRF cells were VO cells (41.1%). Directional preferences also differed between the PPN, which was preferentially modulated during nose-down pitch, and cMRF, which was preferentially modulated during ipsilateral yaw rotation. Finally, amplitude responses were similar between the PPN and cMRF during rotation and pursuit stimuli, but PPN responses to translation were of higher amplitude than cMRF responses. Taken together with their connections to the vestibular circuit, these results implicate the PPN and cMRF in the processing of vestibular stimuli and suggest important roles for both in responding to motion perturbations like falls and turns. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Comparative Transduction Mechanisms of Vestibular Otolith Hair Cells

NASA Technical Reports Server (NTRS)

Baird, Richard A.

1994-01-01

Hair cells in the bullfrog vestibular otolith organs regenerate following aminoglycoside ototoxicity. Hair cells in these organs are differentially sensitive to gentamicin, with saccular hair cells and hair cells in the utricular striola being damaged at lower gentamicin concentrations than hair cells in the utricular extrastriola. Regenerating hair cells in these organs have short hair bundles and can be classified into a number of phenotypes using the same morphological criteria used to identify their mature counterparts. Our studies suggest that some supporting cells can convert, or transdifferentiate,into hair cells without an intervening cell division. By stimulating these processes in humans, clinicians may be able to alleviate human deafness and peripheral vestibular disorders by regenerating and replacing lost hair cells. In vivo and in vitro studies were done on cell proliferation and hair cell regeneration.

Macular Bioaccelerometers on Earth and in Space

NASA Technical Reports Server (NTRS)

Ross, M. D.; Cutler, L.; Meyer, G.; Vazin, P.; Lam, T.

1991-01-01

Space flight offers the opportunity to study linear bioaccelerometers (vestibular maculas) in the virtual absence of a primary stimulus, gravitational acceleration. Macular research in space is particularly important to NASA because the bioaccelerometers are proving to be weighted neural networks in which information is distributed for parallel processing. Neural networks are plastic and highly adaptive to new environments. Combined morphological-physiological studies of maculas fixed in space and following flight should reveal macular adaptive responses to microgravity, and their time-course. Ground-based research, already begun, using computer-assisted, 3-dimensional reconstruction of macular terminal fields will lead to development of computer models of functioning maculas. This research should continue in conjunction with physiological studies, including work with multichannel electrodes. The results of such a combined effort could usher in a new era in understanding vestibular function on Earth and in space. They can also provide a rational basis for counter-measures to space motion sickness, which may prove troublesome as space voyager encounter new gravitational fields on planets, or must re-adapt to 1 g upon return to earth.

Vestibular thalamus: Two distinct graviceptive pathways.

PubMed

Baier, Bernhard; Conrad, Julian; Stephan, Thomas; Kirsch, Valerie; Vogt, Thomas; Wilting, Janine; Müller-Forell, Wibke; Dieterich, Marianne

2016-01-12

To determine whether there are distinct thalamic regions statistically associated with either contraversive or ipsiversive disturbance of verticality perception measured by subjective visual vertical (SVV). We used modern statistical lesion behavior mapping on a sample of 37 stroke patients with isolated thalamic lesions to clarify which thalamic regions are involved in graviceptive otolith processing and whether there are distinct regions associated with contraversive or ipsiversive SVV deviation. We found 2 distinct systems of graviceptive processing within the thalamus. Contraversive tilt of SVV was associated with lesions to the nuclei dorsomedialis, intralamellaris, centrales thalami, posterior thalami, ventrooralis internus, ventrointermedii, ventrocaudales and superior parts of the nuclei parafascicularis thalami. The regions associated with ipsiversive tilt of SVV were located in more inferior regions, involving structures such as the nuclei endymalis thalami, inferior parts of the nuclei parafascicularis thalami, and also small parts of the junction zone of the nuclei ruber tegmenti and brachium conjunctivum. Our data indicate that there are 2 anatomically distinct graviceptive signal processing mechanisms within the vestibular network in humans that lead, when damaged, to a vestibular tone imbalance either to the contraversive or to the ipsiversive side. © 2015 American Academy of Neurology.

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.

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.

Counteracting Muscle Atrophy using Galvanic Stimulation of the Vestibular System

NASA Technical Reports Server (NTRS)

Fox, Robert A.; Polyakov, Igor

1999-01-01

The unloading of weight bearing from antigravity muscles during space flight produces significant muscle atrophy and is one of the most serious health problems facing the space program. Various exercise regimens have been developed and used either alone or in combination with pharmacological techniques to ameliorate this atrophy, but no effective countermeasure exists for this problem. The research in this project was conducted to evaluate the potential use of vestibular galvanic stimulation (VGS) to prevent muscle atrophy resulting from unloading of weight bearing from antigravity muscles. This approach was developed based on two concepts related to the process of maintaining the status of the anti-gravity neuromuscular system. These two premises are: (1) The "tone," or bias on spinal motorneurons is affected by vestibular projections that contribute importantly to maintaining muscle health and status. (2) VGS can be used to modify the excitability, or 'tone' of motorneuron of antigravity muscles. Thus, the strategy is to use VGS to modify the gain of vestibular projections to antigravity muscles and thereby change the general status of these muscles.

Verticality perception during and after galvanic vestibular stimulation.

PubMed

Volkening, Katharina; Bergmann, Jeannine; Keller, Ingo; Wuehr, Max; Müller, Friedemann; Jahn, Klaus

2014-10-03

The human brain constructs verticality perception by integrating vestibular, somatosensory, and visual information. Here we investigated whether galvanic vestibular stimulation (GVS) has an effect on verticality perception both during and after application, by assessing the subjective verticals (visual, haptic and postural) in healthy subjects at those times. During stimulation the subjective visual vertical and the subjective haptic vertical shifted towards the anode, whereas this shift was reversed towards the cathode in all modalities once stimulation was turned off. Overall, the effects were strongest for the haptic modality. Additional investigation of the time course of GVS-induced changes in the haptic vertical revealed that anodal shifts persisted for the entire 20-min stimulation interval in the majority of subjects. Aftereffects exhibited different types of decay, with a preponderance for an exponential decay. The existence of such reverse effects after stimulation could have implications for GVS-based therapy. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

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.

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.

Combined ocular and cervical vestibular evoked myogenic potential in individuals with vestibular hyporeflexia and in patients with Ménière's disease.

PubMed

Silva, Tatiana Rocha; de Resende, Luciana Macedo; Santos, Marco Aurélio Rocha

The vestibular evoked myogenic potential is a potential of mean latency that measures the muscle response to auditory stimulation. This potential can be generated from the contraction of the sternocleidomastoid muscle and also from the contraction of extraocular muscles in response to high-intensity sounds. This study presents a combined or simultaneous technique of cervical and ocular vestibular evoked myogenic potential in individuals with changes in the vestibular system, for use in otoneurologic diagnosis. To characterize the records and analyze the results of combined cervical and ocular VEMP in individuals with vestibular hyporeflexia and in those with Ménière's disease. The study included 120 subjects: 30 subjects with vestibular hyporeflexia, 30 with Ménière's disease, and 60 individuals with normal hearing. Data collection was performed by simultaneously recording the cervical and ocular vestibular evoked myogenic potential. There were differences between the study groups (individuals with vestibular hyporeflexia and individuals with Ménière's disease) and the control group for most of wave parameters in combined cervical and ocular vestibular evoked myogenic potential. For cervical vestibular evoked myogenic potential, it was observed that the prolongation of latency of the P13 and N23 waves was the most frequent finding in the group with vestibular hyporeflexia and in the group with Ménière's disease. For ocular vestibular evoked myogenic potential, prolonged latency of N10 and P15 waves was the most frequent finding in the study groups. Combined cervical and ocular vestibular evoked myogenic potential presented relevant results for individuals with vestibular hyporeflexia and for those with Ménière's disease. There were differences between the study groups and the control group for most of the wave parameters in combined cervical and ocular vestibular evoked myogenic potential. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

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.

Generalization of vestibular learning to earth-fixed targets is possible but limited when the polarity of afferent vestibular information is changed.

PubMed

Mackrous, I; Simoneau, M

2014-02-28

To maintain perception of the world around us during body motion, the brain must update the spatial presentation of visual stimuli, known as space updating. Previous studies have demonstrated that vestibular signals contribute to space updating. Nonetheless, when being passively rotated in the dark, the ability to keep track of a memorized earth-fixed target (EFT) involves learning mechanism(s). We tested whether such learning generalizes across different EFT eccentricities. Furthermore, we ascertained whether learning transfers to similar target eccentricities but in the opposite direction. Participants were trained to predict the position of an EFT (located at 45° to their left) while being rotated counterclockwise (i.e., they press a push button when they perceived that their body midline have cross the position of the target). Overall, the results indicated that learning transferred to other target eccentricity (30° and 60°) for identical body rotation direction. In contrast, vestibular learning partly transferred to target location's matching body rotation but in the opposite rotation direction. Generalization of learning implies that participants do not adopt cognitive strategies to improve their performance during training. We argue that the brain learned to use vestibular signals for space updating. Generalization of learning while being rotated in the opposite direction implies that some parts of the neural networks involved in space updating is shared between trained and untrained direction. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Matters of simulation of the semicircular canal system

NASA Technical Reports Server (NTRS)

Gurfinkel, V. S.; Petukhov, S. V.

1977-01-01

A scale model of the human semicircular canal system was developed based on the theory of dynamic similitude. This enlarged model makes it convenient to conduct tests on the vestibular processes and dynamics in the semicircular canals. Tests revealed hydromechanical interaction between canals, with asymmetry of the conditions of movement of the endolymph in the canals in opposite directions. A type of vestibular reactions, occurring with angular oscillations of the head, was predicted and demonstrated using this model and human test subjects.

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.

Association Between Vestibular Vertigo and Motor Vehicle Accidents: Data From the 2016 National Health Interview Survey.

PubMed

Wei, Eric X; Agrawal, Yuri

2018-05-18

Recent evidence has shown that individuals with vestibular impairment have higher rates of self-reported driving difficulty compared with individuals without vestibular impairment. However, it is unknown whether individuals with vestibular impairment are more likely to be involved in motor vehicle accidents. We used data from the 2016 National Health Interview Survey of U.S. adults to evaluate whether individuals with vestibular vertigo are more likely to experience motor vehicle accidents relative to individuals without vestibular vertigo. In multivariate analysis, vestibular vertigo was associated with an over threefold increased odds of motor vehicle accidents (odds ratio, 3.5; 95% confidence interval, 1.7-7.3). This study supports an assciation between vestibular dysfunction and driving impairment, and provides a relative risk of motor vehicle accidents associated with vestibular vertigo that clinicians may utilize in counseling patients on the potential safety hazards of driving.

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

International survey of vestibular rehabilitation therapists by the Barany Society Ad Hoc Committee on Vestibular Rehabilitation Therapy.

PubMed

Cohen, Helen S; Gottshall, Kim R; Graziano, Mariella; Malmstrom, Eva-Maj; Sharpe, Margaret H

2009-01-01

The goal of this study was to determine how occupational and physical therapists learn about vestibular rehabilitation therapy, their educational backgrounds, referral patterns, and their ideas about entry-level and advanced continuing education in vestibular rehabilitation therapy. The Barany Society Ad Hoc Committee for Vestibular Rehabilitation Therapy invited therapists around the world to complete an E-mail survey. Participants were either known to committee members or other Barany Society members, known to other participants, identified from their self-listings on the Internet, or volunteered after reading notices published in publications read by therapists. Responses were received from 133 therapists in 19 countries. They had a range of educational backgrounds, practice settings, and referral patterns. Few respondents had had any training about vestibular rehabilitation during their professional entry-level education. Most respondents learned about vestibular rehabilitation from continuing education courses, interactions with their colleagues, and reading. All of them endorsed the concept of developing standards and educating therapists about vestibular anatomy and physiology, vestibular diagnostic testing, vestibular disorders and current intervention strategies. Therefore, the Committee recommends the development of international standards for education and practice in vestibular rehabilitation therapy.

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.

Optomotor behaviour in Xenopus laevis tadpoles as a measure of the effect of gravity on visual and vestibular neural integration

NASA Technical Reports Server (NTRS)

Pronych, S. P.; Souza, K. A.; Neff, A. W.; Wassersug, R. J.

1996-01-01

The ability of aquatic vertebrates to maintain their position requires integration of visual and vestibular sensory information. To understand better how aquatic animals integrate such information, we measured the optomotor behaviour of Xenopus laevis tadpoles raised in growth chambers in microgravity (< 10(-3)g), normal gravity (1 g), hypergravity (3 g) and on a slowly rotating clinostat (simulated microgravity). The goal of this research was to determine how development in an altered gravitational force field affects the visual- and vestibular-dependent behaviour of tadpoles. This research represents the first time that the optomotor behaviour of an organism raised from fertilization in microgravity has been tested. Significant differences were observed in the optomotor behaviour among the four gravity treatments. When first exposed to normal gravity, the microgravity-raised tadpoles exhibited the strongest (or most positive) optomotor behaviour, while the 3 g centrifuge tadpoles showed no optomotor response. Some abnormal behaviours (such as erratic swimming, lying motionless and abnormal swimming posture) were observed in the tadpoles raised in altered gravity on the initial day of testing. One day later, the tadpoles raised in hypergravity did not differ significantly in their optomotor behaviour from control tadpoles raised in normal gravity. However, tadpoles raised in microgravity still displayed an exaggerated optomotor response. One week after the tadpoles had been introduced to normal gravity, there was no longer a significant difference in optomotor behaviour among the different gravity treatments. This convergence of optomotor behaviour by tadpoles from the different treatment reflects the acclimation of their vestibular systems to normal gravity.

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.

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

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.

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

PubMed Central

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

2013-01-01

Background In previous imaging studies the insular cortex (IC) has been identified as an essential part of the processing of a wide spectrum of perception and sensorimotor integration. Yet, there are no systematic lesion studies in a sufficient number of patients examining whether processing of vestibular and the interaction of somatosensory and vestibular signals take place in the IC. Methods We investigated acute stroke patients with lesions affecting the IC in order to fill this gap. In detail, we explored signs of a vestibular tone imbalance such as the deviation of the subjective visual vertical (SVV). We applied voxel-lesion behaviour mapping analysis in 27 patients with acute unilateral stroke. Results Our data demonstrate that patients with lesions of the posterior IC have an abnormal tilt of SVV. Furthermore, re-analysing data of 20 patients from a previous study, we found a positive correlation between thermal perception contralateral to the stroke and the severity of the SVV tilt. Conclusions We conclude that the IC is a sensory brain region where different modalities might interact. PMID:24392273

Electric Current Transmission Through Tissues of the Vestibular Labyrinth of a Patient: Perfection of the Vestibular Implant

NASA Astrophysics Data System (ADS)

Demkin, V. P.; Shchetinin, P. P.; Melnichuk, S. V.; Kingma, H.; Van de Berg, R.; Pleshkov, M. O.; Starkov, D. N.

2018-03-01

An electric model of current transmission through tissues of the vestibular labyrinth of a patient is suggested. To stimulate directly the vestibular nerve in surgical operation, terminations of the electrodes are implanted through the bone tissue of the labyrinth into the perilymph in the vicinity of the vestibular nerve. The biological tissue of the vestibular labyrinth surrounding the electrodes and having heterogeneous composition possesses conductive and dielectric properties. Thus, when a current pulse from the vestibular implant is applied to one of the electrodes, conductive disturbance currents may arise between the electrodes and the vestibular nerves that can significantly deteriorate the direct signal quality. To study such signals and to compensate for the conductive disturbance currents, an equivalent electric circuit with actual electric impedance properties of tissues of the vestibular system is suggested, and the time parameters of the conductive disturbance current transmission are calculated. It is demonstrated that these parameters can reach large values. The suggested electric model and the results of calculations can be used for perfection of the vestibular implant.

Evidence of a sensory processing unit in the mammalian macula

NASA Technical Reports Server (NTRS)

Chimento, T. C.; Ross, M. D.

1996-01-01

We cut serial sections through the medial part of the rat vestibular macula for transmission electron microscopic (TEM) examination, computer-assisted 3-D reconstruction, and compartmental modeling. The ultrastructural research showed that many primary vestibular neurons have an unmyelinated segment, often branched, that extends between the heminode (putative site of the spike initiation zone) and the expanded terminal(s) (calyx, calyces). These segments, termed the neuron branches, and the calyces frequently have spine-like processes of various dimensions with bouton endings that morphologically are afferent, efferent, or reciprocal to other macular neural elements. The major questions posed by this study were whether small details of morphology, such as the size and location of neuronal processes or synapses, could influence the output of a vestibular afferent, and whether a knowledge of morphological details could guide the selection of values for simulation parameters. The conclusions from our simulations are (1) values of 5.0 k omega cm2 for membrane resistivity and 1.0 nS for synaptic conductance yield simulations that best match published physiological results; (2) process morphology has little effect on orthodromic spread of depolarization from the head (bouton) to the spike initiation zone (SIZ); (3) process morphology has no effect on antidromic spread of depolarization to the process head; (4) synapses do not sum linearly; (5) synapses are electrically close to the SIZ; and (6) all whole-cell simulations should be run with an active SIZ.

Bio-Inspired Micro-Fluidic Angular-Rate Sensor for Vestibular Prostheses

PubMed Central

Andreou, Charalambos M.; Pahitas, Yiannis; Georgiou, Julius

2014-01-01

This paper presents an alternative approach for angular-rate sensing based on the way that the natural vestibular semicircular canals operate, whereby the inertial mass of a fluid is used to deform a sensing structure upon rotation. The presented gyro has been fabricated in a commercially available MEMS process, which allows for microfluidic channels to be implemented in etched glass layers, which sandwich a bulk-micromachined silicon substrate, containing the sensing structures. Measured results obtained from a proof-of-concept device indicate an angular rate sensitivity of less than 1 °/s, which is similar to that of the natural vestibular system. By avoiding the use of a continually-excited vibrating mass, as is practiced in today's state-of-the-art gyroscopes, an ultra-low power consumption of 300 μW is obtained, thus making it suitable for implantation. PMID:25054631

Bio-inspired micro-fluidic angular-rate sensor for vestibular prostheses.

PubMed

Andreou, Charalambos M; Pahitas, Yiannis; Georgiou, Julius

2014-07-22

This paper presents an alternative approach for angular-rate sensing based on the way that the natural vestibular semicircular canals operate, whereby the inertial mass of a fluid is used to deform a sensing structure upon rotation. The presented gyro has been fabricated in a commercially available MEMS process, which allows for microfluidic channels to be implemented in etched glass layers, which sandwich a bulk-micromachined silicon substrate, containing the sensing structures. Measured results obtained from a proof-of-concept device indicate an angular rate sensitivity of less than 1 °/s, which is similar to that of the natural vestibular system. By avoiding the use of a continually-excited vibrating mass, as is practiced in today's state-of-the-art gyroscopes, an ultra-low power consumption of 300 μW is obtained, thus making it suitable for implantation.

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.

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

[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.

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.

Hearing outcome after concurrent endolymphatic shunt and vestibular nerve section.

PubMed

Moody-Antonio, Stephanie; House, John W

2003-05-01

To determine if endolymphatic shunt surgery concurrent with vestibular nerve section improves hearing outcome compared with vestibular nerve section alone. Retrospective observational study with cross-sectional survey. Tertiary otologic private practice. Thirty-five patients who underwent vestibular nerve section and endolymphatic shunt surgery and 17 patients who had vestibular nerve section alone between 1985 and 2000. Chart review and correspondence for audiogram results and survey. Hearing at last follow-up. Hearing Handicap Inventory, Dizziness Handicap Inventory, Tinnitus Handicap Inventory, and SF-36. Eight patients in the vestibular nerve section and 15 in the vestibular nerve section and endolymphatic shunt surgery group had an audiogram at more than 16 months after surgery available for review. In the vestibular nerve section group, three patients had same hearing whereas five were worse. In the vestibular nerve section and endolymphatic shunt surgery group, 2 patients showed improvement, 2 were the same, and 11 were worse. There was no significant difference in the change from preoperative pure tone average or Word Discrimination Score to postoperative levels between the surgical groups. Eighteen patients had serviceable hearing preoperatively. Five of 8 in the vestibular nerve section and 4 of 10 in the vestibular nerve section and endolymphatic shunt surgery groups maintained serviceable hearing postoperatively. Of the 52 patients, 33 responded to the survey (63%). There were no significant differences between the groups for Dizziness Handicap Inventory, Hearing Handicap Inventory, Tinnitus Handicap Inventory, or SF-36, suggesting that patient-oriented outcomes are the same in both groups. Concurrent endolymphatic shunt surgery and vestibular nerve section does not improve hearing or tinnitus outcome over vestibular nerve section alone.

Vestibular migraine: who is the patient?

PubMed

Colombo, Bruno; Teggi, Roberto

2017-05-01

Vestibular migraine has been classified as a specific entity in which vestibular symptomatology is defined as part of the migrainous disorder. New and appropriate diagnostic criteria have been proposed by the Barany and International Headache Societies. The diagnosis of vestibular migraine mainly depends on the patient history. The NIVE project is a prospectic multicentric study on vestibular migraine. The aim of this project is to evaluate demographics, epidemiology, clinical manifestations of migraine and vertigo in a large cohort of Caucasian patients affected by vestibular migraine.

An optimal state estimation model of sensory integration in human postural balance

NASA Astrophysics Data System (ADS)

Kuo, Arthur D.

2005-09-01

We propose a model for human postural balance, combining state feedback control with optimal state estimation. State estimation uses an internal model of body and sensor dynamics to process sensor information and determine body orientation. Three sensory modalities are modeled: joint proprioception, vestibular organs in the inner ear, and vision. These are mated with a two degree-of-freedom model of body dynamics in the sagittal plane. Linear quadratic optimal control is used to design state feedback and estimation gains. Nine free parameters define the control objective and the signal-to-noise ratios of the sensors. The model predicts statistical properties of human sway in terms of covariance of ankle and hip motion. These predictions are compared with normal human responses to alterations in sensory conditions. With a single parameter set, the model successfully reproduces the general nature of postural motion as a function of sensory environment. Parameter variations reveal that the model is highly robust under normal sensory conditions, but not when two or more sensors are inaccurate. This behavior is similar to that of normal human subjects. We propose that age-related sensory changes may be modeled with decreased signal-to-noise ratios, and compare the model's behavior with degraded sensors against experimental measurements from older adults. We also examine removal of the model's vestibular sense, which leads to instability similar to that observed in bilateral vestibular loss subjects. The model may be useful for predicting which sensors are most critical for balance, and how much they can deteriorate before posture becomes unstable.

Lock-and-key mechanisms of cerebellar memory recall based on rebound currents.

PubMed

Wetmore, Daniel Z; Mukamel, Eran A; Schnitzer, Mark J

2008-10-01

A basic question for theories of learning and memory is whether neuronal plasticity suffices to guide proper memory recall. Alternatively, information processing that is additional to readout of stored memories might occur during recall. We formulate a "lock-and-key" hypothesis regarding cerebellum-dependent motor memory in which successful learning shapes neural activity to match a temporal filter that prevents expression of stored but inappropriate motor responses. Thus, neuronal plasticity by itself is necessary but not sufficient to modify motor behavior. We explored this idea through computational studies of two cerebellar behaviors and examined whether deep cerebellar and vestibular nuclei neurons can filter signals from Purkinje cells that would otherwise drive inappropriate motor responses. In eyeblink conditioning, reflex acquisition requires the conditioned stimulus (CS) to precede the unconditioned stimulus (US) by >100 ms. In our biophysical models of cerebellar nuclei neurons this requirement arises through the phenomenon of postinhibitory rebound depolarization and matches longstanding behavioral data on conditioned reflex timing and reliability. Although CS-US intervals<100 ms may induce Purkinje cell plasticity, cerebellar nuclei neurons drive conditioned responses only if the CS-US training interval was >100 ms. This bound reflects the minimum time for deinactivation of rebound currents such as T-type Ca2+. In vestibulo-ocular reflex adaptation, hyperpolarization-activated currents in vestibular nuclei neurons may underlie analogous dependence of adaptation magnitude on the timing of visual and vestibular stimuli. Thus, the proposed lock-and-key mechanisms link channel kinetics to recall performance and yield specific predictions of how perturbations to rebound depolarization affect motor expression.

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.

The Association Between Vestibular Physical Examination, Vertigo Questionnaires, and the Electronystagmography in Patients With Vestibular Symptoms.

PubMed

Gofrit, Shany G; Mayler, Yulia; Eliashar, Ron; Bdolah-Abram, Tali; Ilan, Ophir; Gross, Menachem

2017-04-01

Dizziness makes up a diagnostic and treatment challenge. The diagnostic accuracy of the medical history and vestibular physical examination in cases of vestibular symptoms is not clear. The aim of this study is to determine the association between vestibular physical examination, vestibular questionnaires, and electronystagmography (ENG) test in patients with vestibular symptoms. This is a prospective study of 135 adults with vestibular symptoms. The subjects underwent targeted physical examination and filled vestibular questionnaires, including the Dizziness Handicap Inventory (DHI), before ENG testing. The results of the physical examination and questionnaires were compared with the final ENG findings. Of patients who had normal ENG results, 32.1% (17/52) showed abnormal physical examination, and 48.8% (40/82) of the patient who had normal physical examination showed abnormal ENG results ( P = .46). Among patients with severe disability by DHI, 46.4% (13/28) had an abnormal ENG, and 42.9% (12/28) had a normal ENG ( P = .39). This study did not demonstrate association between vestibular physical examination, vestibular questionnaires, and ENG results. Although history (augmented by questionnaires) and physical examination are the initial steps in the evaluation of vertigo, the current study suggests that they should be complemented by objective testing for evaluation of inner ear origin of vertigo.

Vestibular Findings in Military Band Musicians

PubMed Central

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

2014-01-01

Introduction Exposure to music is the subject of many studies because it is related to an individual's professional and social activities. Objectives Evaluate the vestibular behavior in military band musicians. Methods A retrospective cross-sectional study was performed. Nineteen musicians with ages ranging from 21 to 46 years were evaluated (average = 33.7 years and standard deviation = 7.2 years). They underwent anamnesis and vestibular and otolaryngologic evaluation through vectoelectronystagmography. Results The most evident otoneurologic symptoms in the anamnesis were tinnitus (84.2%), hearing difficulties (47.3%), dizziness (36.8%), headache (26.3%), intolerance to intense sounds (21.0%), and earache (15.7%). Seven musicians (37.0%) showed vestibular abnormality, which occurred in the caloric test. The abnormality was more prevalent in the peripheral vestibular system, and there was a predominance of irritative peripheral vestibular disorders. Conclusion The alteration in vestibular exam occurred in the caloric test (37.0%). There were changes in the prevalence of peripheral vestibular system with a predominance of irritative vestibular dysfunction. Dizziness was the most significant symptom for the vestibular test in correlation with neurotologic symptoms. The present study made it possible to verify the importance of the labyrinthine test, which demonstrates that this population should be better studied because the systematic exposure to high sound pressure levels may cause major vestibular alterations. PMID:25992076

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.

Interaction of somatoform and vestibular disorders

PubMed Central

Best, C; Eckhardt‐Henn, A; Diener, G; Bense, S; Breuer, P; Dieterich, M

2006-01-01

Background The high coincidence of organic vestibular and somatoform vertigo syndromes has appeared to support pathogenic models showing a strong linkage between them. It was hypothesised that a persisting vestibular dysfunction causes the development of anxiety disorders. Objective To determine the relation between vestibular deficits and somatoform vertigo disorders in an interdisciplinary prospective study. Methods Participants were divided into eight diagnostic groups: healthy volunteers (n = 26) and patients with benign paroxysmal positioning vertigo (BPPV, n = 11), vestibular neuritis (n = 11), Menière's disease (n = 7), vestibular migraine (n = 15), anxiety (n = 23), depression (n = 12), or somatoform disorders (n = 22). Neuro‐otological diagnostic procedures included electro‐oculography with rotatory and caloric testing, orthoptic examination with measurements of subjective visual vertical (SVV) and ocular torsion, and a neurological examination. Psychosomatic diagnostic procedures comprised interviews and psychometric instruments. Results Patients with BPPV (35.3%) and with vestibular neuritis (52.2%) had pathological test values on caloric irrigation (p<0.001). Otolith dysfunction with pathological tilts of SVV and ocular torsion was found only in patients with vestibular neuritis (p<0.001). Patients with Menière's disease, vestibular migraine, and psychiatric disorders showed normal parameters for vestibular testing but pathological values for psychometric measures. There was no correlation between pathological neurological and pathological psychometric parameters. Conclusions High anxiety scores are not a result of vestibular deficits or dysfunction. Patients with Menière's disease and vestibular migraine but not vestibular deficits showed the highest psychiatric comorbidity. Thus the course of vertigo syndromes and the possibility of a pre‐existing psychopathological personality should be considered pathogenic factors in any linkage between organic and psychometric vertigo syndromes. PMID:16614028

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.

Manually controlled human balancing using visual, vestibular and proprioceptive senses involves a common, low frequency neural process

PubMed Central

Lakie, Martin; Loram, Ian D

2006-01-01

Ten subjects balanced their own body or a mechanically equivalent unstable inverted pendulum by hand, through a compliant spring linkage. Their balancing process was always characterized by repeated small reciprocating hand movements. These bias adjustments were an observable sign of intermittent alterations in neural output. On average, the adjustments occurred at intervals of ∼400 ms. To generate appropriate stabilizing bias adjustments, sensory information about body or load movement is needed. Subjects used visual, vestibular or proprioceptive sensation alone and in combination to perform the tasks. We first ask, is the time between adjustments (bias duration) sensory specific? Vision is associated with slow responses. Other senses involved with balance are known to be faster. Our second question is; does bias duration depend on sensory abundance? An appropriate bias adjustment cannot occur until unplanned motion is unambiguously perceived (a sensory threshold). The addition of more sensory data should therefore expedite action, decreasing the mean bias adjustment duration. Statistical analysis showed that (1) the mean bias adjustment duration was remarkably independent of the sensory modality and (2) the addition of one or two sensory modalities made a small, but significant, decrease in the mean bias adjustment duration. Thus, a threshold effect can alter only a very minor part of the bias duration. The bias adjustment duration in manual balancing must reflect something more than visual sensation and perceptual thresholds; our suggestion is that it is a common central motor planning process. We predict that similar processes may be identified in the control of standing. PMID:16959857

[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.

Epidemiology of balance symptoms and disorders in the community: a systematic review.

PubMed

Murdin, Louisa; Schilder, Anne G M

2015-03-01

Balance disorders presenting with symptoms of dizziness or vertigo may have significant impact on quality of life and are a recognized risk factor for falls. The objective of this review was to systematically synthesize the published literature on the epidemiology of balance symptoms and disorders in the adult community population. A search was carried out across PubMed, Medline, and Cochrane databases to identify suitable studies. Studies were eligible for inclusion if they contained data on the epidemiology of symptoms of balance disorders (dizziness and vertigo) or balance disorders sampled from community-based adult populations. Data were collected on prevalence and incidence of balance symptoms and on specific balance disorders. A validated risk-of-bias assessment was carried out. Twenty eligible studies were identified. The lifetime prevalence estimates of significant dizziness ranged between 17 and 30%, and for vertigo between 3 and 10%. Published point prevalence data exist for Ménière's disease (0.12-0.5%) and for vestibular migraine (0.98%). For benign paroxysmal positional vertigo, 1-year incidence estimates range from 0.06 to 0.6%. There are no community-based studies on the prevalence or incidence of chronic uncompensated peripheral vestibular disorders or vestibular neuritis. Symptoms of dizziness and vertigo are common in the adult population, and data give a coherent picture of community epidemiology. These data can inform rational service planning and much-needed clinical trials in this field. There are insufficient data on specific balance disorders, especially peripheral vestibular disorders such as vestibular neuritis and its long-term sequelae.

Visual-vestibular cue integration for heading perception: applications of optimal cue integration theory.

PubMed

Fetsch, Christopher R; Deangelis, Gregory C; Angelaki, Dora E

2010-05-01

The perception of self-motion is crucial for navigation, spatial orientation and motor control. In particular, estimation of one's direction of translation, or heading, relies heavily on multisensory integration in most natural situations. Visual and nonvisual (e.g., vestibular) information can be used to judge heading, but each modality alone is often insufficient for accurate performance. It is not surprising, then, that visual and vestibular signals converge frequently in the nervous system, and that these signals interact in powerful ways at the level of behavior and perception. Early behavioral studies of visual-vestibular interactions consisted mainly of descriptive accounts of perceptual illusions and qualitative estimation tasks, often with conflicting results. In contrast, cue integration research in other modalities has benefited from the application of rigorous psychophysical techniques, guided by normative models that rest on the foundation of ideal-observer analysis and Bayesian decision theory. Here we review recent experiments that have attempted to harness these so-called optimal cue integration models for the study of self-motion perception. Some of these studies used nonhuman primate subjects, enabling direct comparisons between behavioral performance and simultaneously recorded neuronal activity. The results indicate that humans and monkeys can integrate visual and vestibular heading cues in a manner consistent with optimal integration theory, and that single neurons in the dorsal medial superior temporal area show striking correlates of the behavioral effects. This line of research and other applications of normative cue combination models should continue to shed light on mechanisms of self-motion perception and the neuronal basis of multisensory integration.

Therapeutic profile of single-fraction radiosurgery of vestibular schwannoma: unrelated malignancy predicts tumor control

PubMed Central

Wowra, Berndt; Muacevic, Alexander; Fürweger, Christoph; Schichor, Christian; Tonn, Jörg-Christian

2012-01-01

Radiosurgery has become an accepted treatment option for vestibular schwannomas. Nevertheless, predictors of tumor control and treatment toxicity in current radiosurgery of vestibular schwannomas are not well understood. To generate new information on predictors of tumor control and cranial nerve toxicity of single-fraction radiosurgery of vestibular schwannomas, we conducted a single-institution long-term observational study of radiosurgery for sporadic vestibular schwannomas. Minimum follow-up was 3 years. Investigated as potential predictors of tumor control and cranial nerve toxicity were treatment technology; tumor resection preceding radiosurgery; tumor size; gender; patient age; history of cancer, vascular disease, or metabolic disease; tumor volume; radiosurgical prescription dose; and isodose line. Three hundred eighty-six patients met inclusion criteria. Treatment failure was observed in 27 patients. History of unrelated cancer (strongest predictor) and prescription dose significantly predicted tumor control. The cumulative incidence of treatment failure was 30% after 6.5 years in patients with unrelated malignancy and 10% after ≥15 years in patients without such cancer (P < .02). Tumor volume was the only predictor of trigeminal neuropathy (observed in 6 patients). No predictor of facial nerve toxicity was found. On the House and Brackmann scale, 1 patient had a permanent one-level drop and 7 a transient drop of 1 to 3 levels. Serviceable hearing was preserved in 75.1%. Tumor hearing before radiosurgery, recurrence, and prescription isodose predicted ototoxicity. Unrelated malignancy is a strong predictor of tumor control. Tumor recurrence predominantly predicts ototoxicity. These findings potentially will aid future clinical decision making in ambiguous cases. PMID:22561798

Isolation of sphere-forming stem cells from the mouse inner ear.

PubMed

Oshima, Kazuo; Senn, Pascal; Heller, Stefan

2009-01-01

The mammalian inner ear has very limited ability to regenerate lost sensory hair cells. This deficiency becomes apparent when hair cell loss leads to hearing loss as a result of either ototoxic insult or the aging process. Coincidently, with this inability to regenerate lost hair cells, the adult cochlea does not appear to harbor cells with a proliferative capacity that could serve as progenitor cells for lost cells. In contrast, adult mammalian vestibular sensory epithelia display a limited ability for hair cell regeneration, and sphere-forming cells with stem cell features can be isolated from the adult murine vestibular system. The neonatal inner ear, however, does harbor sphere-forming stem cells residing in cochlear and vestibular tissues. Here, we provide protocols to isolate sphere-forming stem cells from neonatal vestibular and cochlear sensory epithelia as well as from the spiral ganglion. We further describe procedures for sphere propagation, cell differentiation, and characterization of inner ear cell types derived from spheres. Sphere-forming stem cells from the mouse inner ear are an important tool for the development of cellular replacement strategies of damaged inner ears and are a bona fide progenitor cell source for transplantation studies.

Comparison of Postural Responses to Galvanic Vestibular Stimulation between Pilots and the General Populace

PubMed Central

Yang, Yang; Pu, Fang; Lv, Xiaoning; Li, Shuyu; Li, Jing; Li, Deyu; Li, Minggao

2015-01-01

Galvanic vestibular stimulation (GVS) can be used to study the body's response to vestibular stimuli. This study aimed to investigate whether postural responses to GVS were different between pilots and the general populace. Bilateral bipolar GVS was applied with a constant-current profile to 12 pilots and 12 control subjects via two electrodes placed over the mastoid processes. Both GVS threshold and the center of pressure's trajectory (COP's trajectory) were measured. Position variability of COP during spontaneous body sway and peak displacement of COP during GVS-induced body sway were calculated in the medial-lateral direction. Spontaneous body sway was slight for all subjects, and there was no significant difference in the value of COP position variability between the pilots and controls. Both the GVS threshold and magnitude of GVS-induced body deviation were similar for different GVS polarities. GVS thresholds were similar between the two groups, but the magnitude of GVS-induced body deviation in the controls was significantly larger than that in the pilots. The pilots showed less GVS-induced body deviation, meaning that pilots may have a stronger ability to suppress vestibular illusions. PMID:25632395

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.

Adaptation to vestibular disorientation. XII, Habituation of vestibular responses : an overview.

DOT National Transportation Integrated Search

1974-03-01

Vestibular and visual mechanisms are critical sensing systems in spatial orientation and in spatial disorientation. In aviation or space environments in particular, the role of the vestibular system is central to the problems of spatial disorientatio...

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.

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.

Vestibular morphology in the German Waltzing guinea pig.

PubMed

Kawaguchi, Sachie; Hultcrantz, Malou; Jin, Zhe; Ulfendahl, Mats; Suzuki, Mamoru

2010-04-01

The German waltzing guinea pig is a special strain of animal with a recessively inherited inner ear defect, resulting in deafness and a severe vestibular dysfunction. The hearing loss in the cochlea of the German strain is a result of a collapse of the Reissner membrane and the absence of scala media. The vestibular organ has not yet been described. German waltzing guinea pigs (homozygote and heterozygote) of different ages ranging from embryologic age 25 days to adulthood were investigated. The living animals were tested with four different vestibular tests, and the fetuses were controlled according to breeding. The morphology of the vestibular parts (ampulla, saccule, and utricle) was observed by using the light and transmission electron microscopy. Collapse of the membranous labyrinth was found already at embryologic age 50 days and progressed over time. Vestibular dysfunction was noted already from birth. Vestibular atelectasis has been shown to have the same morphology as the reported vestibular dysfunction in the German waltzing guinea pig. Owing to this similarity, this animal can be a good model for vestibular research.

Effect of transcranial direct current stimulation on vestibular-ocular and vestibulo-perceptual thresholds.

PubMed

Kyriakareli, Artemis; Cousins, Sian; Pettorossi, Vito E; Bronstein, Adolfo M

2013-10-02

Transcranial direct current stimulation (tDCS) was used in 17 normal individuals to modulate vestibulo-ocular reflex (VOR) and self-motion perception rotational thresholds. The electrodes were applied over the temporoparietal junction bilaterally. Both vestibular nystagmic and perceptual thresholds were increased during as well as after tDCS stimulation. Body rotation was labeled as ipsilateral or contralateral to the anode side, but no difference was observed depending on the direction of rotation or hemisphere polarity. Threshold increase during tDCS was greater for VOR than for motion perception. 'Sham' stimulation had no effect on thresholds. We conclude that tDCS produces an immediate and sustained depression of cortical regions controlling VOR and movement perception. Temporoparietal areas appear to be involved in vestibular threshold modulation but the differential effects observed between VOR and perception suggest a partial dissociation between cortical processing of reflexive and perceptual responses.

Vestibular and Visual Contribution to Fish Behavior Under Microgravity

NASA Astrophysics Data System (ADS)

Ijiri, K.

Vestibular and visual information are two major factors fish use for controlling their posture under 1 G conditions. Parabolic flight experiments were carried out to observe the fish behavior under microgravity for several different strains of Medaka fish (Oryzias latipes). There existed a clear strain-difference in the behavioral response of the fish under microgravity: Some strains looped, while other strains did not loop at all. However, even the latter strains looped under microgravity conditions when kept in complete darkness, suggesting the contribution of visual information to the posture control under microgravity. In the laboratory, eyesight (visual acuity) was checked for each strain, using a rotating striped-drum apparatus. The results also showed a strain-difference, which gave a clue to the different degree of adaptability to microgravity among different strains. Beside loopings, some fish exhibited rolling movement around their body axis. Tracing each fish during and between parabolas, it was shown that to which side each fish rolls was determined specifically to each individual fish, and not to each strain. Thus, rolling direction is not genetically determined. This may support the otolith asymmetry hypothesis. Fish of a mutant strain (ha strain, having homozygous recessive of one gene ha) have some malfunction in otolith-vestibular system, and their behavior showed they are not dependent on gravity. Morphological abnormalities of their ear vesicles during the embryonic and baby stages were noted. Their eyesight and dorsal light responses were also studied. Progress in the project of establishing a new strain which has good eyesight and, at the same time, being deficient in otolith-vestibular system was reported. Crosses between the strain of good eyesight and ha strain were made, and to some extent, F2 fish have already shown such characteristics suited for living under microgravity conditions

The internal representation of head orientation differs for conscious perception and balance control.

PubMed

Dalton, Brian H; Rasman, Brandon G; Inglis, J Timothy; Blouin, Jean-Sébastien

2017-04-15

We tested perceived head-on-feet orientation and the direction of vestibular-evoked balance responses in passively and actively held head-turned postures. The direction of vestibular-evoked balance responses was not aligned with perceived head-on-feet orientation while maintaining prolonged passively held head-turned postures. Furthermore, static visual cues of head-on-feet orientation did not update the estimate of head posture for the balance controller. A prolonged actively held head-turned posture did not elicit a rotation in the direction of the vestibular-evoked balance response despite a significant rotation in perceived angular head posture. It is proposed that conscious perception of head posture and the transformation of vestibular signals for standing balance relying on this head posture are not dependent on the same internal representation. Rather, the balance system may operate under its own sensorimotor principles, which are partly independent from perception. Vestibular signals used for balance control must be integrated with other sensorimotor cues to allow transformation of descending signals according to an internal representation of body configuration. We explored two alternative models of sensorimotor integration that propose (1) a single internal representation of head-on-feet orientation is responsible for perceived postural orientation and standing balance or (2) conscious perception and balance control are driven by separate internal representations. During three experiments, participants stood quietly while passively or actively maintaining a prolonged head-turned posture (>10 min). Throughout the trials, participants intermittently reported their perceived head angular position, and subsequently electrical vestibular stimuli were delivered to elicit whole-body balance responses. Visual recalibration of head-on-feet posture was used to determine whether static visual cues are used to update the internal representation of body configuration for perceived orientation and standing balance. All three experiments involved situations in which the vestibular-evoked balance response was not orthogonal to perceived head-on-feet orientation, regardless of the visual information provided. For prolonged head-turned postures, balance responses consistent with actual head-on-feet posture occurred only during the active condition. Our results indicate that conscious perception of head-on-feet posture and vestibular control of balance do not rely on the same internal representation, but instead treat sensorimotor cues in parallel and may arrive at different conclusions regarding head-on-feet posture. The balance system appears to bypass static visual cues of postural orientation and mainly use other sensorimotor signals of head-on-feet position to transform vestibular signals of head motion, a mechanism appropriate for most daily activities. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

The intrinsic organization of the vestibular complex: evidence for internuclear connectivity.

PubMed

Rubertone, J A; Mehler, W R; Cox, G E

1983-03-14

The HRP anterograde and retrograde labeling techniques provide evidence for extensive internuclear connectivity within the vestibular complex. Specifically: (1) the superior vestibular nucleus is topographically and reciprocally related to the spinal (spr) and medial vestibular nuclei (mv); (2) the lateral vestibular nucleus (lv) is reciprocally related to the mv, and (3) the lv receives afferent fibers from the spv but does not reciprocate this input.

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.

78 FR 53700 - Revised Medical Criteria for Evaluating Hearing Loss and Disturbances of Labyrinthine-Vestibular...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-30

... SOCIAL SECURITY ADMINISTRATION 20 CFR Part 404 [Docket No. SSA-2012-0075] RIN 0960-AH54 Revised...: Social Security Administration. ACTION: Advance notice of proposed rulemaking (ANPRM). SUMMARY: We are... your comments any personal information, such as Social Security numbers or medical information. 1...

Neuro-vestibular and Sensory-motor Challenges Associated with NASA Mission Architectures for Moon and Mars

NASA Technical Reports Server (NTRS)

Paloski, William H.

2004-01-01

Data from six-month low Earth orbit space flight missions suggest that that substantial neuro-vestibular/sensory-motor adaptation will take place during six-month transit missions to and from Mars. Could intermittent or continuous artificial gravity be used to offset these effects? To what degree would the effects of adaptation to this rotational cure affect its potential benefits? Also, little information exists regarding the gravity thresholds for maintaining functional performance of complex sensory-motor tasks such as balance control and locomotion. Will sensory-motor coordination systems adapt to 30- 90 days of 1/6 g on the lunar surface or 18 months of 3/8 g on the Martian surface? Would some form of gravity replacement therapy be required on the surface? And, will transitions between 0 g and 1/6 g or 1/3 g present as great a challenge to the vestibular system as transitions between 0 g and 1 g? Concerted research and development efforts will be required to obtain the answers.

Multisensory Integration and Internal Models for Sensing Gravity Effects in Primates

PubMed Central

Lacquaniti, Francesco; La Scaleia, Barbara; Maffei, Vincenzo

2014-01-01

Gravity is crucial for spatial perception, postural equilibrium, and movement generation. The vestibular apparatus is the main sensory system involved in monitoring gravity. Hair cells in the vestibular maculae respond to gravitoinertial forces, but they cannot distinguish between linear accelerations and changes of head orientation relative to gravity. The brain deals with this sensory ambiguity (which can cause some lethal airplane accidents) by combining several cues with the otolith signals: angular velocity signals provided by the semicircular canals, proprioceptive signals from muscles and tendons, visceral signals related to gravity, and visual signals. In particular, vision provides both static and dynamic signals about body orientation relative to the vertical, but it poorly discriminates arbitrary accelerations of moving objects. However, we are able to visually detect the specific acceleration of gravity since early infancy. This ability depends on the fact that gravity effects are stored in brain regions which integrate visual, vestibular, and neck proprioceptive signals and combine this information with an internal model of gravity effects. PMID:25061610

Multisensory integration and internal models for sensing gravity effects in primates.

PubMed

Lacquaniti, Francesco; Bosco, Gianfranco; Gravano, Silvio; Indovina, Iole; La Scaleia, Barbara; Maffei, Vincenzo; Zago, Myrka

2014-01-01

Gravity is crucial for spatial perception, postural equilibrium, and movement generation. The vestibular apparatus is the main sensory system involved in monitoring gravity. Hair cells in the vestibular maculae respond to gravitoinertial forces, but they cannot distinguish between linear accelerations and changes of head orientation relative to gravity. The brain deals with this sensory ambiguity (which can cause some lethal airplane accidents) by combining several cues with the otolith signals: angular velocity signals provided by the semicircular canals, proprioceptive signals from muscles and tendons, visceral signals related to gravity, and visual signals. In particular, vision provides both static and dynamic signals about body orientation relative to the vertical, but it poorly discriminates arbitrary accelerations of moving objects. However, we are able to visually detect the specific acceleration of gravity since early infancy. This ability depends on the fact that gravity effects are stored in brain regions which integrate visual, vestibular, and neck proprioceptive signals and combine this information with an internal model of gravity effects.

Vestibular Evoked Myogenic Potentials in Normal Mice and Phex Mice With Spontaneous Endolymphatic Hydrops

PubMed Central

Sheykholeslami, Kianoush; Megerian, Cliff A.; Zheng, Qing Y.

2010-01-01

Objective and Background Vestibular evoked myogenic potentials (VEMPs) have been recorded from the neck musculature and the cervical spinal cord in humans and a limited number of laboratory animals in response to loud sound. However, the mouse VEMP has yet to be described. Evaluation of the sacculocollic pathway via VEMPs in mice can set the stage for future evaluations of mutant mice that now play an important role in research regarding human auditory and vestibular dysfunction. Materials and Methods Sound-evoked potentials were recorded from the neck extensor muscles and the cervical spinal cord in normal adult mice and in circling PhexHyp-Duk/y mice with known vestibular abnormalities, including endolymphatic hydrops (ELH). Results Biphasic potentials were recorded from all normal animals. The mean threshold of the VEMP response in normal adult mice was 60 dB normal hearing level with a mean peak latency of 6.25 ± 0.46 and 7.95 ± 0.42 milliseconds for p1 and n1 peaks, respectively. At the maximum sound intensity used (100 dB normal hearing level), 4 of 5 Phex mice did not exhibit VEMP responses, and 1 showed an elevated threshold, but normal response, with regard to peak latency and amplitude. The histologic findings in all of these Phex mice were consistent with distended membranous labyrinth, displaced Reissner membrane, ganglion cell loss, and ELH. Conclusion This is the first report of VEMP recordings in mice and the first report of abnormal VEMPs in a mouse model with ELH. The characteristics of these potentials such as higher response threshold in comparison to auditory brainstem response, myogenic nature of the response, and latency correlation with the cervical recording (accessory nerve nucleus) were similar to those of VEMPs in humans, guinea pigs, cats, and rats, suggesting that the mouse may be used as an animal model in the study of VEMPs. The simplicity and reliability of these recordings make the VEMP a uniquely informative test for assessing vestibular function, and these results suggest that they may be informative in mice with various mutations. However, further investigation is necessary. PMID:19300299

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.

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.

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

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.

Vestibular Schwannoma (Acoustic Neuroma) and Neurofibromatosis

MedlinePlus

... other brain tumors. In addition, scientists are developing robotic technology to assist physicians with acoustic neuroma surgery. ... Privacy Accessibility Freedom of Information Act Site Map Website Policies Free Publications Content Syndication U.S. Department of ...

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 and Spatial Orientation Driven by Virtual Reality

PubMed Central

Keshner, Emily A.; Kenyon, Robert V.

2009-01-01

Orientation in space is a perceptual variable intimately related to postural orientation that relies on visual and vestibular signals to correctly identify our position relative to vertical. We have combined a virtual environment with motion of a posture platform to produce visual-vestibular conditions that allow us to explore how motion of the visual environment may affect perception of vertical and, consequently, affect postural stabilizing responses. In order to involve a higher level perceptual process, we needed to create a visual environment that was immersive. We did this by developing visual scenes that possess contextual information using color, texture, and 3-dimensional structures. Update latency of the visual scene was close to physiological latencies of the vestibulo-ocular reflex. Using this system we found that even when healthy young adults stand and walk on a stable support surface, they are unable to ignore wide field of view visual motion and they adapt their postural orientation to the parameters of the visual motion. Balance training within our environment elicited measurable rehabilitation outcomes. Thus we believe that virtual environments can serve as a clinical tool for evaluation and training of movement in situations that closely reflect conditions found in the physical world. PMID:19592796

Motion sickness and development of synergy within the spatial orientation system. A hypothetical unifying concept

NASA Technical Reports Server (NTRS)

Guedry, F. E.; Rupert, A. R.; Reschke, M. F.

1998-01-01

Adaptation to research paradigms such as rotating rooms and optical alteration of visual feedback during movement results in development of perceptual-motor programs that provide the reflexive assistance that is necessary to skilled control of movement and balance. The discomfort and stomach awareness that occur during the adaptation process has been attributed to conflicting sensory information about the state of motion. Vestibular signals depend on the kinematics of head movements irrespective of the presence or absence of signals from other senses. We propose that sensory conflict when vestibular signals are at least one component of the conflict are innately disturbing and unpleasant. This innate reaction is part of a continuum that operates early in life to prevent development of inefficient perceptual-motor programs. This reaction operates irrespective of and in addition to reward and punishment from parental guidance or goal attainment to yield efficient control of whole body movement in the operating environment of the individual. The same mechanism is involved in adapting the spatial orientation system to strange environments. This conceptual model "explains" why motion sickness is associated with adaptation to novel environments and is in general consistent with motion sickness literature.

Acute adaptation of the vestibuloocular reflex: signal processing by floccular and ventral parafloccular Purkinje cells.

PubMed

Hirata, Y; Highstein, S M

2001-05-01

The gain of the vertical vestibuloocular reflex (VVOR), defined as eye velocity/head velocity was adapted in squirrel monkeys by employing visual-vestibular mismatch stimuli. VVOR gain, measured in the dark, could be trained to values between 0.4 and 1.5. Single-unit activity of vertical zone Purkinje cells was recorded from the flocculus and ventral paraflocculus in alert squirrel monkeys before and during the gain change training. Our goal was to evaluate the site(s) of learning of the gain change. To aid in the evaluation, a model of the vertical optokinetic reflex (VOKR) and VVOR was constructed consisting of floccular and nonfloccular systems divided into subsystems based on the known anatomy and input and output parameters. Three kinds of input to floccular Purkinje cells via mossy fibers were explicitly described, namely vestibular, visual (retinal slip), and efference copy of eye movement. The characteristics of each subsystem (gain and phase) were identified at different VOR gains by reconstructing single-unit activity of Purkinje cells during VOKR and VVOR with multiple linear regression models consisting of sensory input and motor output signals. Model adequacy was checked by evaluating the residual following the regressions and by predicting Purkinje cells' activity during visual-vestibular mismatch paradigms. As a result, parallel changes in identified characteristics with VVOR adaptation were found in the prefloccular/floccular subsystem that conveys vestibular signals and in the nonfloccular subsystem that conveys vestibular signals, while no change was found in other subsystems, namely prefloccular/floccular subsystems conveying efference copy or visual signals, nonfloccular subsystem conveying visual signals, and postfloccular subsystem transforming Purkinje cell activity to eye movements. The result suggests multiple sites for VVOR motor learning including both flocculus and nonflocculus pathways. The gain change in the nonfloccular vestibular subsystem was in the correct direction to cause VOR gain adaptation while the change in the prefloccular/floccular vestibular subsystem was incorrect (anti-compensatory). This apparent incorrect directional change might serve to prevent instability of the VOR caused by positive feedback via the efference copy pathway.

Vestibular factors influencing the biomedical support of humans in space

NASA Astrophysics Data System (ADS)

Lichtenberg, Byron K.

This paper will describe the biomedical support aspects of humans in space with respect to the vestibular system. The vestibular system is thought to be the primary sensory system involved in the short-term effects of space motion sickness although there is increasing evidence that many factors play a role in this complex set of symptoms. There is the possibility that an individual's inner sense of orientation may be strongly coupled with the susceptibility to space motion sickness. A variety of suggested countermeasures for space motion sickness will be described. Although there are no known ground-based tests that can predict space motion sickness, the search should go on. The long term effects of the vestibular system in weightlessness are still relatively unknown. Some preliminary data has shown that the otoconia are irregular in size and distribution following extended periods of weightlessness. The ramifications of this data are not yet known and because the data was obtained on lower order animals, definitive studies and results must wait until the space station era when higher primates can be studied for long durations. This leads us to artificial gravity, the last topic of this paper. The vestibular system is intimately tied to this question since it has been shown on Earth that exposure to a slow rotating room causes motion sickness for some period of time before adaptation occurs. If the artificial gravity is intermittent, will this mean that people will get sick every time they experience it? The data from many astronauts returning to Earth indicates that a variety of sensory illusions are present, especially immediately upon return to a 1- g environment. Oscillopsia or apparent motion of the visual surround upon head motion along with inappropriate eye motions for a given head motion, all indicate that there is much to be studied yet about the vestibular and CNS systems reaction to a sudden application of a steady state acceleration field like 1- g. From the above information it is obvious that the vestibular system does have unique requirements when it comes to the biomedical support of space flight. This is not to say that other areas such as cardiovascular, musculo-skeletal, immunological and hematological systems do not have their own unique requirements but that possible solutions to one system can provide continuing problems to another system. For example, artificial gravity might be helpful for long term stabilization of bone demineralization or cardiovascular deconditioning but might introduce a new set of problems in orientation, vestibular conflict and just plain body motion in a rotating space vehicle.

Vestibular factors influencing the biomedical support of humans in space

NASA Technical Reports Server (NTRS)

Lichtenberg, B. K.

1988-01-01

This paper will describe the biomedical support aspects of humans in space with respect to the vestibular system. The vestibular system is thought to be the primary sensory system involved in the short-term effects of space motion sickness although there is increasing evidence that many factors play a role in this complex set of symptoms. There is the possibility that an individual's inner sense of orientation may be strongly coupled with the susceptibility to space motion sickness. A variety of suggested countermeasures for space motion sickness will be described. Although there are no known ground-based tests that can predict space motion sickness, the search should go on. The long term effects of the vestibular system in weightlessness are still relatively unknown. Some preliminary data has shown that the otoconia are irregular in size and distribution following extended periods of weightlessness. The ramifications of this data are not yet known and because the data was obtained on lower order animals, definitive studies and results must wait until the space station era when higher primates can be studied for long durations. This leads us to artificial gravity, the last topic of this paper. The vestibular system is intimately tied to this question since it has been shown on Earth that exposure to a slow rotating room causes motion sickness for some period of time before adaptation occurs. If the artificial gravity is intermittent, will this mean that people will get sick every time they experience it? The data from many astronauts returning to Earth indicates that a variety of sensory illusions are present, especially immediately upon return to a 1-g environment. Oscillopsia or apparent motion of the visual surround upon head motion along with inappropriate eye motions for a given head motion, all indicate that there is much to be studied yet about the vestibular and CNS systems reaction to a sudden application of a steady state acceleration field like 1-g. From the above information it is obvious that the vestibular system does have unique requirements when it comes to the biomedical support of space flight. This is not to say that other areas such as cardiovascular, musculo-skeletal, immunological and hematological systems do not have their own unique requirements but that possible solutions to one system can provide continuing problems to another system. For example, artificial gravity might be helpful for long term stabilization of bone demineralization or cardiovascular deconditioning but might introduce a new set of problems in orientation, vestibular conflict and just plain body motion in a rotating space vehicle.

Vestibular factors influencing the biomedical support of humans in space.

PubMed

Lichtenberg, B K

1988-01-01

This paper will describe the biomedical support aspects of humans in space with respect to the vestibular system. The vestibular system is thought to be the primary sensory system involved in the short-term effects of space motion sickness although there is increasing evidence that many factors play a role in this complex set of symptoms. There is the possibility that an individual's inner sense of orientation may be strongly coupled with the susceptibility to space motion sickness. A variety of suggested countermeasures for space motion sickness will be described. Although there are no known ground-based tests that can predict space motion sickness, the search should go on. The long term effects of the vestibular system in weightlessness are still relatively unknown. Some preliminary data has shown that the otoconia are irregular in size and distribution following extended periods of weightlessness. The ramifications of this data are not yet known and because the data was obtained on lower order animals, definitive studies and results must wait until the space station era when higher primates can be studied for long durations. This leads us to artificial gravity, the last topic of this paper. The vestibular system is intimately tied to this question since it has been shown on Earth that exposure to a slow rotating room causes motion sickness for some period of time before adaptation occurs. If the artificial gravity is intermittent, will this mean that people will get sick every time they experience it? The data from many astronauts returning to Earth indicates that a variety of sensory illusions are present, especially immediately upon return to a 1-g environment. Oscillopsia or apparent motion of the visual surround upon head motion along with inappropriate eye motions for a given head motion, all indicate that there is much to be studied yet about the vestibular and CNS systems reaction to a sudden application of a steady state acceleration field like 1-g. From the above information it is obvious that the vestibular system does have unique requirements when it comes to the biomedical support of space flight. This is not to say that other areas such as cardiovascular, musculo-skeletal, immunological and hematological systems do not have their own unique requirements but that possible solutions to one system can provide continuing problems to another system. For example, artificial gravity might be helpful for long term stabilization of bone demineralization or cardiovascular deconditioning but might introduce a new set of problems in orientation, vestibular conflict and just plain body motion in a rotating space vehicle.

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.

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.

The prevalence of vestibular symptoms in migraine or tension-type headache.

PubMed

Akdal, Gülden; Ozge, Aynur; Ergör, Gül

2013-01-01

We assessed frequency of vestibular symptoms in Headache Clinic patients over 10 years. A descriptive study of 5111 consecutive patients with tension-type headache or migraine, analyzed for dizziness/ vertigo accompanying headache and for a lifetime history of motion-sickness, cyclic vomiting, recurrent abdominal pain or atopy. Migraine patients were re-grouped as those with vestibular symptoms (dizziness/vertigo or motion sickness) and those without and their data then re-analyzed. There were 1880 migraine patients and 3231 tension-type headache patients. Significantly more migraine patients than tension-type headache patients experienced vestibular symptoms (p< 0.0001). The migraine with vestibular symptoms group was significantly younger (p< 0.05) had more aura, more phonophobia with migraine attacks (p< 0.0001). Menstruation and reported sleep problems impacted on headaches. While past history of cyclical vomiting, recurrent abdominal pain or atopy was about twice as common in migraine with aura and it was also more common in migraine with vestibular symptoms than migraine without vestibular symptoms. Vestibular symptoms are common in migraine patients. Migraine with vestibular symptoms might constitute a special group, one more likely to have had cyclic vomiting, recurrent abdominal pain or atopy.

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

Effects of microgravity on vestibular ontogeny: direct physiological and anatomical measurements following space flight (STS-29)

NASA Technical Reports Server (NTRS)

Jones, T. A.; Fermin, C.; Hester, P. Y.; Vellinger, J.

1993-01-01

Does space flight change gravity receptor development? The present study measured vestibular form and function in birds flown as embryos for 5 days in earth orbit (STS-29). No major changes in vestibular gross morphology were found. Vestibular response mean amplitudes and latencies were unaffected by space flight. However, the results of measuring vestibular thresholds were mixed and abnormal responses in 3 of the 8 flight animals raise important questions.

[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).

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.

Refractory episodic vertigo: role of intratympanic gentamicin and vestibular evoked myogenic potentials.

PubMed

Celis-Aguilar, Erika; Hinojosa-González, Ramon; Vales-Hidalgo, Olivia; Coutinho-Toledo, Heloisa

Even today, the treatment of intractable vertigo remains a challenge. Vestibular ablation with intratympanic gentamicin stands as a good alternative in the management of refractory vertigo patients. To control intractable vertigo through complete saccular and horizontal canal vestibular ablation with intratympanic gentamicin treatment. Patients with refractory episodic vertigo were included. The inclusion criteria were: unilateral ear disease, moderate to profound sensorineural hearing loss, and failure to other treatments. Included patients underwent 0.5-0.8mL of gentamicin intratympanic application at a 30mg/mL concentration. Vestibular ablation was confirmed by the absence of response on cervical vestibular evoked myogenic potentials and no response on caloric tests. Audiometry, electronystagmography with iced water, and vestibular evoked myogenic potentials were performed in all patients. Ten patients were included; nine patients with Meniere's disease and one patient with (late onset) delayed hydrops. Nine patients showed an absent response on vestibular evoked myogenic potentials and no response on caloric tests. The only patient with low amplitude on cervical vestibular evoked myogenic potentials had vertigo recurrence. Vertigo control was achieved in 90% of the patients. One patient developed hearing loss >30dB. Cervical vestibular evoked myogenic potentials confirmed vestibular ablation in patients treated with intratympanic gentamicin. High-grade vertigo control was due to complete saccular and horizontal canal ablation (no response to iced water in electronystagmography and no response on cervical vestibular evoked myogenic potentials). Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Cerebellopontine angle epidermoid tumour presenting with bilateral gaze nystagmus.

PubMed

Han, I B; Huh, R; Chung, S S; Kim, O J

2008-06-01

Vestibular symptoms have been rarely described in cerebellopontine angle epidermoid tumours. We report a case of CPA epidermoid tumour presenting with subacute onset of vestibular symptoms such as vertigo, gait ataxia, and nystagmus masquerading as acute vestibular neuritis or central vertigo. The vestibular symptoms disappeared after excision of the tumour.

Vestibular schwannomas: Accuracy of tumor volume estimated by ice cream cone formula using thin-sliced MR images.

PubMed

Ho, Hsing-Hao; Li, Ya-Hui; Lee, Jih-Chin; Wang, Chih-Wei; Yu, Yi-Lin; Hueng, Dueng-Yuan; Ma, Hsin-I; Hsu, Hsian-He; Juan, Chun-Jung

2018-01-01

We estimated the volume of vestibular schwannomas by an ice cream cone formula using thin-sliced magnetic resonance images (MRI) and compared the estimation accuracy among different estimating formulas and between different models. The study was approved by a local institutional review board. A total of 100 patients with vestibular schwannomas examined by MRI between January 2011 and November 2015 were enrolled retrospectively. Informed consent was waived. Volumes of vestibular schwannomas were estimated by cuboidal, ellipsoidal, and spherical formulas based on a one-component model, and cuboidal, ellipsoidal, Linskey's, and ice cream cone formulas based on a two-component model. The estimated volumes were compared to the volumes measured by planimetry. Intraobserver reproducibility and interobserver agreement was tested. Estimation error, including absolute percentage error (APE) and percentage error (PE), was calculated. Statistical analysis included intraclass correlation coefficient (ICC), linear regression analysis, one-way analysis of variance, and paired t-tests with P < 0.05 considered statistically significant. Overall tumor size was 4.80 ± 6.8 mL (mean ±standard deviation). All ICCs were no less than 0.992, suggestive of high intraobserver reproducibility and high interobserver agreement. Cuboidal formulas significantly overestimated the tumor volume by a factor of 1.9 to 2.4 (P ≤ 0.001). The one-component ellipsoidal and spherical formulas overestimated the tumor volume with an APE of 20.3% and 29.2%, respectively. The two-component ice cream cone method, and ellipsoidal and Linskey's formulas significantly reduced the APE to 11.0%, 10.1%, and 12.5%, respectively (all P < 0.001). The ice cream cone method and other two-component formulas including the ellipsoidal and Linskey's formulas allow for estimation of vestibular schwannoma volume more accurately than all one-component formulas.

A Conceptual Framework for the Progression of Balance Exercises in Persons with Balance and Vestibular Disorders

PubMed Central

Klatt, BN; Carender, WJ; Lin, CC; Alsubaie, SF; Kinnaird, CR; Sienko, KH; Whitney, SL

2016-01-01

There is little information in peer-reviewed literature to specifically guide the choice of exercise for persons with balance and vestibular disorders. The purpose of this study is to provide a rationale for the establishment of a progression framework and propose a logical sequence in progressing balance exercises for persons with vestibular disorders. Our preliminary conceptual framework was developed by a multidisciplinary team of physical therapists and engineers with extensive experience with people with vestibular disorders. Balance exercises are grouped into six different categories: static standing, compliant surface, weight shifting, modified center of gravity, gait, and vestibulo-ocular reflex (VOR). Through a systematized literature review, interviews and focus group discussions with physical therapists and postural control experts, and pilot studies involving repeated trials of each exercise, exercise progressions for each category were developed and ranked in order of degree of difficulty. Clinical expertise and experience guided decision making for the exercise progressions. Hundreds of exercise combinations were discussed and research is ongoing to validate the hypothesized rankings. The six exercise categories can be incorporated into a balance training program and the framework for exercise progression can be used to guide less experienced practitioners in the development of a balance program. It may also assist clinicians and researchers to design, develop, and progress interventions within a treatment plan of care, or within clinical trials. A structured exercise framework has the potential to maximize postural control, decrease symptoms of dizziness/visual vertigo, and provide “rules” for exercise progression for persons with vestibular disorders. The conceptual framework may also be applicable to persons with other balance-related issues. PMID:27489886

Basic Gravitational Reflexes in the Larval Frog

NASA Technical Reports Server (NTRS)

Cochran, Stephen L.

1996-01-01

This investigation was designed to determine how a primitive vertebrate, the bullfrog tadpole, is able to sense and process gravitational stimuli. Because of the phylogenetic similarities of the vestibular systems in all vertebrates, the understanding of the gravitational reflexes in this relatively simple vertebrate should elucidate a skeletal framework on a elementary level, upon which the more elaborate reflexes of higher vertebrates may be constructed. The purpose of this study was to understand how the nervous system of the larval amphibian processes gravitational information. This study involved predominantly electrophysiological investigations of the isolated, alert (forebrain removed) bullfrog tadpole head. The focus of these experiments is threefold: (1) to understand from whole extraocular nerve recordings the signals sent to the eye following static gravitational tilt of the head; (2) to localize neuronal centers responsible for generating these signals through reversible pharmacological ablation of these centers; and (3) to record intracellularly from neurons within these centers in order to determine the single neuron's role in the overall processing of the center. This study has provided information on the mechanisms by which a primitive vertebrate processes gravitational reflexes.

Biomechanical versus Inertial Information: Stable Individual Differences in Perception of Self-Rotation

ERIC Educational Resources Information Center

Bruggeman, Hugo; Piuneu, Vadzim S.; Rieser, John J.; Pick, Herbert L., Jr.

2009-01-01

When turning without vision or audition, people tend to perceive their locomotion as a change in heading relative to objects in the remembered surroundings. Such perception of self-rotation depends on sensitivity to information for movement from biomechanical activity of the locomotor system or from inertial activation of the vestibular and…

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 control of standing balance is enhanced with increased cognitive load.

PubMed

McGeehan, Michael A; Woollacott, Marjorie H; Dalton, Brian H

2017-04-01

When cognitive load is elevated during a motor task, cortical inhibition and reaction time are increased; yet, standing balance control is often unchanged. This disconnect is likely explained by compensatory mechanisms within the balance system such as increased sensitivity of the vestibulomotor pathway. This study aimed to determine the effects of increased cognitive load on the vestibular control of standing balance. Participants stood blindfolded on a force plate with their head facing left and arms relaxed at their sides for two trials while exposed to continuous electrical vestibular stimulation (EVS). Participants either stood quietly or executed a cognitive task (double-digit arithmetic). Surface electromyography (EMG) and anterior-posterior ground-body forces (APF) were measured in order to evaluate vestibular-evoked balance responses in the frequency (coherence and gain) and time (cumulant density) domains. Total distance traveled for anterior-posterior center of pressure (COP) was assessed as a metric of balance variability. Despite similar distances traveled for COP, EVS-medial gastrocnemius (MG) EMG and EVS-APF coherence and EVS-TA EMG and EVS-MG EMG gain were elevated for multiple frequencies when standing with increased cognitive load. For the time domain, medium-latency peak amplitudes increased by 13-54% for EVS-APF and EVS-EMG relationships with the cognitive task compared to without. Peak short-latency amplitudes were unchanged. These results indicate that reliance on vestibular control of balance is enhanced when cognitive load is elevated. This augmented neural strategy may act to supplement divided cortical processing resources within the balance system and compensate for the acute neuromuscular modifications associated with increased cognitive demand.

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.

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.

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.

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

Neural correlates of sensory prediction errors in monkeys: evidence for internal models of voluntary self-motion in the cerebellum.

PubMed

Cullen, Kathleen E; Brooks, Jessica X

2015-02-01

During self-motion, the vestibular system makes essential contributions to postural stability and self-motion perception. To ensure accurate perception and motor control, it is critical to distinguish between vestibular sensory inputs that are the result of externally applied motion (exafference) and that are the result of our own actions (reafference). Indeed, although the vestibular sensors encode vestibular afference and reafference with equal fidelity, neurons at the first central stage of sensory processing selectively encode vestibular exafference. The mechanism underlying this reafferent suppression compares the brain's motor-based expectation of sensory feedback with the actual sensory consequences of voluntary self-motion, effectively computing the sensory prediction error (i.e., exafference). It is generally thought that sensory prediction errors are computed in the cerebellum, yet it has been challenging to explicitly demonstrate this. We have recently addressed this question and found that deep cerebellar nuclei neurons explicitly encode sensory prediction errors during self-motion. Importantly, in everyday life, sensory prediction errors occur in response to changes in the effector or world (muscle strength, load, etc.), as well as in response to externally applied sensory stimulation. Accordingly, we hypothesize that altering the relationship between motor commands and the actual movement parameters will result in the updating in the cerebellum-based computation of exafference. If our hypothesis is correct, under these conditions, neuronal responses should initially be increased--consistent with a sudden increase in the sensory prediction error. Then, over time, as the internal model is updated, response modulation should decrease in parallel with a reduction in sensory prediction error, until vestibular reafference is again suppressed. The finding that the internal model predicting the sensory consequences of motor commands adapts for new relationships would have important implications for understanding how responses to passive stimulation endure despite the cerebellum's ability to learn new relationships between motor commands and sensory feedback.

Evaluating Inhibition of Motoneuron Firing From Electromyogram Data to Assess Vestibular Output Using Vestibular Evoked Myogenic Potentials.

PubMed

Prakash, S R; Herrmann, Barbara S; Milojcic, Rupprecht; Rauch, Steven D; Guinan, John J

2015-01-01

Vestibular evoked myogenic potentials (VEMPs) are due to vestibular responses producing brief inhibitions of muscle contractions that are detectable in electromyographic (EMG) responses. VEMP amplitudes are traditionally measured by the peak to peak amplitude of the averaged EMG response (VEMPpp) or by a normalized VEMPpp (nVEMPpp). However, a brief EMG inhibition does not satisfy the statistical assumptions for the average to be the optimal processing strategy. Here, it is postulated that the inhibition depth of motoneuron firing is the desired metric for showing the influence of the vestibular system on the muscle system. The authors present a metric called "VEMPid" that estimates this inhibition depth from the EMG data obtained in a usual VEMP data acquisition. The goal of this article was to compare how well VEMPid, VEMPpp, and nVEMPpp track inhibition depth. To find a robust method to compare VEMPid, VEMPpp, and nVEMPpp, realistic physiological models for the inhibition of VEMP EMG signals were made using VEMP data from four measurement sessions on each of the five normal subjects. Each of the resulting 20 EMG-production models was adjusted to match the EMG autocorrelation of an individual subject and session. Simulated VEMP traces produced by these models were used to compare how well VEMPid, VEMPpp, and nVEMPpp tracked model inhibition depth. Applied to simulated and real VEMP data, VEMPid showed good test-retest consistency and greater sensitivity at low stimulus levels than VEMPpp or nVEMPpp. For large-amplitude responses, nVEMPpp and VEMPid were equivalent in their consistency across subjects and sessions, but for low-amplitude responses, VEMPid was superior. Unnormalized VEMPpp was always worse than nVEMPpp or VEMPid. VEMPid provides a more reliable measurement of vestibular function at low sound levels than the traditional nVEMPpp, without requiring a change in how VEMP tests are performed. The calculation method for VEMPid should be applicable whenever an ongoing muscle contraction is briefly inhibited by an external stimulus.

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.

Posturography of ataxia induced by Coriolis- and Purkinje-effects.

PubMed

Fitger, C; Brandt, T

1982-02-01

Vestibular Coriolis- and Purkinje-effect, which are known to induce vertigo, were investigated with respect to body posture. One aim of this investigation was to provide information concerning clinical vertigo symptoms. Standing on a rotatable stabilometer, 25 healthy subjects had to execute lateral head tilts during (Coriolis), or after (Purkinje), rotation varied with different constant velocities. The conditions were varied with respect to eyes open vs. eyes closed, head upright vs. head tilt to the right and left, direction of rotation clockwise vs. counterclockwise, active vs. passive head tilt, and active vs. passive body rotation. The results supported the expectation that destabilization was less severe with open than with closed eyes and that sway amplitudes were increased after head tilt as well as with a higher velocity of rotation. The direction of the induced body shift was, as expected, opposite to the initial vestibular stimulus. A forward shift after stop without head tilt was frequently found, being independent of the previous direction of rotation. Reported perceptions coincided mostly not with the initial vestibular signal but rather with the actual movement of compensation. Active instead of passive movements did not produce clearly different effects. The Purkinje experiment appeared to be equivalent to the situation when a patient with an acute lesion of a horizontal vestibular canal bends his head. The stabilogram under this condition may allow a prediction of the side of the lesion.

Radiotherapy for Vestibular Schwannomas: A Critical Review

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

Murphy, Erin S., E-mail: murphye3@ccf.or; Suh, John H.

2011-03-15

Vestibular schwannomas are slow-growing tumors of the myelin-forming cells that cover cranial nerve VIII. The treatment options for patients with vestibular schwannoma include active observation, surgical management, and radiotherapy. However, the optimal treatment choice remains controversial. We have reviewed the available data and summarized the radiotherapeutic options, including single-session stereotactic radiosurgery, fractionated conventional radiotherapy, fractionated stereotactic radiotherapy, and proton beam therapy. The comparisons of the various radiotherapy modalities have been based on single-institution experiences, which have shown excellent tumor control rates of 91-100%. Both stereotactic radiosurgery and fractionated stereotactic radiotherapy have successfully improved cranial nerve V and VII preservation tomore » >95%. The mixed data regarding the ideal hearing preservation therapy, inherent biases in patient selection, and differences in outcome analysis have made the comparison across radiotherapeutic modalities difficult. Early experience using proton therapy for vestibular schwannoma treatment demonstrated local control rates of 84-100% but disappointing hearing preservation rates of 33-42%. Efforts to improve radiotherapy delivery will focus on refined dosimetry with the goal of reducing the dose to the critical structures. As future randomized trials are unlikely, we suggest regimented pre- and post-treatment assessments, including validated evaluations of cranial nerves V, VII, and VIII, and quality of life assessments with long-term prospective follow-up. The results from such trials will enhance the understanding of therapy outcomes and improve our ability to inform patients.« less

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.

Long-term mobile phone use and the risk of vestibular schwannoma: a Danish nationwide cohort study.

PubMed

Schüz, Joachim; Steding-Jessen, Marianne; Hansen, Søren; Stangerup, Sven-Eric; Cayé-Thomasen, Per; Poulsen, Aslak Harbo; Olsen, Jørgen H; Johansen, Christoffer

2011-08-15

Vestibular schwannomas grow in the region within the brain where most of the energy by radiofrequency electromagnetic fields from using mobile phones is absorbed. The authors used 2 Danish nationwide cohort studies, one a study of all adult Danes subscribing for a mobile phone in 1995 or earlier and one on sociodemographic factors and cancer risk, and followed subjects included in both cohorts for occurrence of vestibular schwannoma up to 2006 inclusively. In this study including 2.9 million subjects, a long-term mobile phone subscription of ≥11 years was not related to an increased vestibular schwannoma risk in men (relative risk estimate = 0.87, 95% confidence interval: 0.52, 1.46), and no vestibular schwannoma cases among long-term subscribers occurred in women versus 1.6 expected. Vestibular schwannomas did not occur more often on the right side of the head, although the majority of Danes reported holding their mobile phone to the right ear. Vestibular schwannomas in long-term male subscribers were not of larger size than expected. Overall, no evidence was found that mobile phone use is related to the risk of vestibular schwannoma. Because of the usually slow growth of vestibular schwannoma and possible diagnostic delay, further surveillance is indicated.

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.

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.

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.

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.

Central and peripheral components of short latency vestibular responses in the chicken

NASA Technical Reports Server (NTRS)

Nazareth, A. M.; Jones, T. A.

1998-01-01

Far-field recordings of short latency vestibular responses to pulsed cranial translation are composed of a series of positive and negative peaks occurring within 10 ms following stimulus onset. In the bird, these vestibular evoked potentials (VsEPs) can be recorded noninvasively and have been shown in the chicken and quail to depend strictly upon the activation of the vestibular component of the eighth nerve. The utility of the VsEP in the study of vestibular systems is dependent upon a clear understanding of the neural sources of response components. The primary aim of the current research in the chicken was to critically test the hypotheses that 1) responses are generated by both peripheral and central neurons and 2) peaks P1 and N1 originate from first order vestibular neurons, whereas later waves primarily depend on activity in higher order neurons. The principal strategy used here was to surgically isolate the eighth nerve as it enters the brainstem. Interruption of primary afferents of the eighth nerve in the brainstem substantially reduced or eliminated peaks beyond P2, whereas P1 and N1 were generally spared. Surgical sections that spared vestibular pathways had little effect on responses. The degree of change in response components beyond N1 was correlated with the extent of damage to central vestibular relays. These findings support the conclusion that responses are produced by both peripheral and central elements of the vestibular system. Further, response peaks later than N1 appear to be dependent upon central relays, whereas P1 and N1 reflect activity of the peripheral nerve. These findings clarify the roles of peripheral and central neurons in the generation of vestibular evoked potentials and provide the basis for a more useful and detailed interpretation of data from vestibular response testing.

Sequential [(18)F]FDG µPET whole-brain imaging of central vestibular compensation: a model of deafferentation-induced brain plasticity.

PubMed

Zwergal, Andreas; Schlichtiger, Julia; Xiong, Guoming; Beck, Roswitha; Günther, Lisa; Schniepp, Roman; Schöberl, Florian; Jahn, Klaus; Brandt, Thomas; Strupp, Michael; Bartenstein, Peter; Dieterich, Marianne; Dutia, Mayank B; la Fougère, Christian

2016-01-01

Unilateral inner ear damage is followed by a rapid behavioural recovery due to central vestibular compensation. In this study, we utilized serial [(18)F]Fluoro-deoxyglucose ([(18)F]FDG)-µPET imaging in the rat to visualize changes in brain glucose metabolism during behavioural recovery after surgical and chemical unilateral labyrinthectomy, to determine the extent and time-course of the involvement of different brain regions in vestibular compensation and test previously described hypotheses of underlying mechanisms. Systematic patterns of relative changes of glucose metabolism (rCGM) were observed during vestibular compensation. A significant asymmetry of rCGM appeared in the vestibular nuclei, vestibulocerebellum, thalamus, multisensory vestibular cortex, hippocampus and amygdala in the acute phase of vestibular imbalance (4 h). This was followed by early vestibular compensation over 1-2 days where rCGM re-balanced between the vestibular nuclei, thalami and temporoparietal cortices and bilateral rCGM increase appeared in the hippocampus and amygdala. Subsequently over 2-7 days, rCGM increased in the ipsilesional spinal trigeminal nucleus and later (7-9 days) rCGM increased in the vestibulocerebellum bilaterally and the hypothalamus and persisted in the hippocampus. These systematic dynamic rCGM patterns during vestibular compensation, were confirmed in a second rat model of chemical unilateral labyrinthectomy by serial [(18)F]FDG-µPET. These findings show that deafferentation-induced plasticity after unilateral labyrinthectomy involves early mechanisms of re-balancing predominantly in the brainstem vestibular nuclei but also in thalamo-cortical and limbic areas, and indicate the contribution of spinocerebellar sensory inputs and vestibulocerebellar adaptation at the later stages of behavioural recovery.

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

NASA Astrophysics Data System (ADS)

Bruce, L.

Long-term space flight creates unique environmental conditions to which the vestibular system must adapt for optimal survival. We are studying two aspects of this vestibular adaptation: (1) How does long-term exposure to microgravity and hypergravity affect the development of vestibular afferents? (2) How does short- term exposure to extremely rapid changes in gravity, such as those that occur during launch and landing, affect the vestibular system. During space flight the gravistatic receptors in the otolith organs are effectively unloaded. In hypergravity conditions they are overloaded. However, the angular acceleration receptors of the semicircular canals receive relatively normal stimulation in both micro- and hypergravity.Rat embryos exposed to microgravity from gestation day 10 (prior to vestibular function) until gestation day 20 (vestibular system is somewhat functional) showed that afferents from the posterior vertical canal projecting to the medial vestibular nucleus developed similarly in microgravity, hypergravity, and in controls . However, afferents from the saccule showed delayed development in microgravity as compared to development in hypergravity and in controls. Cerebellar plasticity is crucial for modification of sensory-motor control and learning. Thus we explored the possibility that strong vestibular stimuli would modify cerebellar motor control (i.e., eye movement, postural control, gut motility) by altering the morphology of cerebellar Purkinje cells. To study the effects of short-term exposures to strong vestibular stimuli we focused on structural changes in the vestibulo-cerebellum that are caused by strong vestibular stimuli. Adult mice were exposed to various combinations of constant and/or rapidly changing angular and linear accelerations for 8.5 min (the time length of shuttle launch). Our data shows that these stimuli cause intense excitation of cerebellar Purkinje cells, inducing up-regulation of clathrin-mediated endocytosis. Different types of stimulation affect Purkinje cells in particular locations of the vestibulo-cerebellum. This system allows us to study how the vestibular environment can modify cerebellar function, allowing animals to adapt to new environments. Supported by NASA grant NAG2-1353.

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

Spatial Reorientation of Sensorimotor Balance Control in Altered Gravity

NASA Technical Reports Server (NTRS)

Paloski, W. H.; Black, F. L.; Kaufman, G. D.; Reschke, M. F.; Wood, S. J.

2007-01-01

Sensorimotor coordination of body segments following space flight are more pronounced after landing when the head is actively tilted with respect to the trunk. This suggests that central vestibular processing shifts from a gravitational frame of reference to a head frame of reference in microgravity. A major effect of such changes is a significant postural instability documented by standard head-erect Sensory Organization Tests. Decrements in functional performance may still be underestimated when head and gravity reference frames remained aligned. The purpose of this study was to examine adaptive changes in spatial processing for balance control following space flight by incorporating static and dynamic tilts that dissociate head and gravity reference frames. A second aim of this study was to examine the feasibility of altering the re-adaptation process following space flight by providing discordant visual-vestibular-somatosensory stimuli using short-radius pitch centrifugation.

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

Anatomy, Physiology and Function of the Auditory System

NASA Astrophysics Data System (ADS)

Kollmeier, Birger

The human ear consists of the outer ear (pinna or concha, outer ear canal, tympanic membrane), the middle ear (middle ear cavity with the three ossicles malleus, incus and stapes) and the inner ear (cochlea which is connected to the three semicircular canals by the vestibule, which provides the sense of balance). The cochlea is connected to the brain stem via the eighth brain nerve, i.e. the vestibular cochlear nerve or nervus statoacusticus. Subsequently, the acoustical information is processed by the brain at various levels of the auditory system. An overview about the anatomy of the auditory system is provided by Figure 1.

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).

The use of a tactile interface to convey position and motion perceptions

NASA Technical Reports Server (NTRS)

Rupert, A. H.; Guedry, F. E.; Reschke, M. F.

1994-01-01

Under normal terrestrial conditions, perception of position and motion is determined by central nervous system integration of concordant and redundant information from multiple sensory channels (somatosensory, vestibular, visual), which collectively yield vertical perceptions. In the acceleration environment experienced by the pilots, the somatosensory and vestibular sensors frequently present false information concerning the direction of gravity. When presented with conflicting sensory information, it is normal for pilots to experience episodes of disorientation. We have developed a tactile interface that obtains vertical roll and pitch information from a gyro-stabilized attitude indicator and maps this information in a one-to-one correspondence onto the torso of the body using a matrix of vibrotactors. This enables the pilot to continuously maintain an awareness of aircraft attitude without reference to visual cues, utilizing a sensory channel that normally operates at the subconscious level. Although initially developed to improve pilot spatial awareness, this device has obvious applications to 1) simulation and training, 2) nonvisual tracking of targets, which can reduce the need for pilots to make head movements in the high-G environment of aerial combat, and 3) orientation in environments with minimal somatosensory cues (e.g., underwater) or gravitational cues (e.g., space).

[Squirrel monkey--an ideal primate (correction of prmate) model of space physiology].

PubMed

Matsunami, K

1997-06-01

Investigation of the vestibulo-ocular system of the squirrel monkey was reviewed in consideration of space motion sickness (SMS), or which is recently more often termed as space adaptation syndrome (SAS). Since the first launching of the space satellite, Sputnik [correction of Sputonik] in October 1957, many experiments were carried out in biological and medical fields. A various kind of creatures were used as experimental models from protozoa to human beings. Rats and monkeys are most favorite animals, particularly the non-human primate seems to be the one, because of its phylogenetic relatives akin to the human beings. Chimpanzees, rhesus monkeys, pig tailed-monkeys, red-faced monkeys and squirrel monkeys have been used mostly in American space experiments. Russian used rhesus monkeys. Among these, however, the squirrel monkey has an advantage of the small size of the body, ranging from 600- l000g in adult. This small size as a primate is very advantageous in experiments conducted in a narrow room of the space satellite or shuttle because of its space-saving. The squirrel monkey has another advantage to rear easily as is demonstrated to keep it as a pet. Accordingly, this petit animal provides us a good animal model in biological and medical experiments in space craft. The size of the brain of the squirrel monkey is extraordinary large relative to the body size, which is even superior to that of the human beings. This is partly owed to enlargement of the occipito-temporal cortices, which are forced to well develop for processing a huge amount of audio-visual information indispensable to the arboreal habitant to survive in tropical forest. The vestibular system of the squirrel monkey seems to be the most superior as well, when judged from it relative size of the vestibular nuclear complex. Balancing on swinging twigs or jumping from tree to tree developed the capability of this equilibrium system. Fernandez, Goldberg and his collaborators used the squirrel monkey to elucidate functions of the peripheral vestibular system. A transfer function was proposed to explain the behaviors of regular and irregular unit activity of vestibular nerve fibers. The physiologic characteristics of the second order vestibular neuron was investigated in combination of electrophysiological and micro-morphological way, with using WGA-HRP methods, in relation to somato-motor and eye movements. Interconnections between vestibular neurons and cerebellum, interstitial nucleus of Cajal, oculomotor nuclear complex, superior colliculus and cervical spinal cord were elucidated. In physiological field of the vestibular system, the vestibulo-ocular reflex is well studied and results obtained from the squirrel monkey experiments were reviewed. The squirrel monkey, particularly the Bolivian, is a unique animal in that it is vulnerable to motion sickness induced by visual-motion stimulation with phase mismatch of the two stimuli. Experimental results of labyrinthectomy or bilateral ablation of the maculae staticae led to the conclusion that both semicircular and otolith organs are involved in the genesis of space motion sickness. On the other hand, destruction of the area postrema, acknowledged as the vomiting center to chemical stimulants, produced controversial results. However, it must be pointed out that the a human subject underwent to resection of the area postrema, became insensitive to administration of apomorphine, a well known chemical stimulant of vomiting. Finally the experiments in space revealed the presence of at least two origins of caloric nystagmus, that is, attributable to convection and non-convection current of the endolymphatic fluid.

Galvanic vestibular stimulation speeds visual memory recall.

PubMed

Wilkinson, David; Nicholls, Sophie; Pattenden, Charlotte; Kilduff, Patrick; Milberg, William

2008-08-01

The experiments of Alessandro Volta were amongst the first to indicate that visuo-spatial function can be altered by stimulating the vestibular nerves with galvanic current. Until recently, the beneficial effects of the procedure were masked by the high levels of electrical current applied, which induced nystagmus-related gaze deviation and spatial disorientation. However, several neuropsychological studies have shown that much weaker, imperceptible currents that do not elicit unpleasant side-effects can help overcome visual loss after stroke. Here, we show that visual processing in neurologically healthy individuals can also benefit from galvanic vestibular stimulation. Participants first learnt the names of eight unfamiliar faces and then after a short delay, answered questions from memory about how pairs of these faces differed. Mean correct reaction times were significantly shorter when sub-sensory, noise-enhanced anodal stimulation was administered to the left mastoid, compared to when no stimulation was administered at all. This advantage occurred with no loss in response accuracy, and raises the possibility that the procedure may constitute a more general form of cognitive enhancement.

[Pigment and ion transport in the vestibular organ].

PubMed

Meyer zum Gottesberge-Orsulakova, A

1985-07-01

Pigments are found in various parts of the inner ear, especially in the neighbourhood of epithelia, which are supposed to be involved in the secretion and/or absorbtion of the endolymphatic fluid. Microprobe analysis (laser absorption mass micro analyzer "LAMMA" and X-ray) combined with morphological observations were performed in shock frozen, freeze-dried and plastic embedded inner ear tissue from the vestibular organ of pigmented guinea pig. Disturbance of the endolymphatic ionic composition (increased Na+) due to treatment with metabolic inhibitors (ethacrynic acid, ouabain) stimulated the migration of pigment granules and displacement of the dentritic processes of the melanocytes in a close vicinity to the presumably transporting vestibular epithelia (the dark and light cells and capillaries). The melanosomes obtained full range of metal ions that changed characteristically after treatment with metabolic inhibitors. It could be supposed that melanin presents some kind of reservoir for essential trace elements or compounds and may regulate numerous enzymatic and membrane functions by binding and releasing the metal ions.

Left caloric vestibular stimulation as a tool to reveal implicit and explicit parameters of body representation.

PubMed

Sedda, A; Tonin, D; Salvato, G; Gandola, M; Bottini, G

2016-04-01

Homeostatic parameters, such as temperature, are related to body representation. In this study, we measured whether caloric vestibular stimulation (CVS) alters body temperature and tactile processing, and if in the direction predicted by a holistic body matrix representation. Skin temperature and tactile two-point discrimination (TPD) acuity were measured for both arms before, immediately after and with a delay from CVS. Participants were also administered a personality questionnaire and an anxiety inventory to rule out confounding factors. Two control experiments were planned to exclude casual variations. Our results show that temperature drops significantly in both arms after CVS. CVS also induces a bilateral improvement in tactile acuity (even though not immediately after but in the delayed condition). Finally, these effects are not due to learning, as demonstrated by the control experiment. In summary, our results suggest that vestibular stimulation updates body representation, supporting the evidence in favor of a body matrix. Copyright © 2016 Elsevier Inc. All rights reserved.

Normal findings in vulvar examination and vulvoscopy.

PubMed

van Beurden, M; van der Vange, N; de Craen, A J; Tjong-A-Hung, S P; ten Kate, F J; ter Schegget, J; Lammes, F B

1997-03-01

To determine the normal vulvar findings by naked eye examination and by vulvoscopy in healthy women without vulvar complaints. Observational study. Forty healthy volunteers without vulvar complaints recruited via a newspaper advertisement. Vulvar examination, human papillomavirus (HPV) polymerase chain reaction of vulvar and cervical swabs, saline and KOH smears and vulvoscopy before and after the application of 5% acetic acid. Prevalence of vestibular erythema, vestibular papillomatosis, HPV infection on the vulva and in the cervix and vulvoscopic findings. The mean age of the women was 37.8 years (median 38.0, range 21-56). Nine women were current smokers and 21 had previously smoked. Naked eye vulvar examination showed vestibular papillomatosis in 13 women (33%) and vestibular erythema in 17 women (43%). The touch test was positive in 9 of the 17 women (53%) with vestibular erythema. Vulvoscopy after the application of acetic acid 5% showed an acetowhite vestibule in all women. Twelve women (30%) had acetowhite lesions outside the vestibule. Six women (15%) were positive for HPV DNA. The presence of HPV DNA did not correlate with vestibular erythema or vestibular papillomatosis. There was a weak association between HPV DNA and acetowhite lesions outside the vestibule (P = 0.055, Fisher's exact test). In this group the younger women significantly more often had vestibular papillomatosis (t-statistic = 3.07; P = 0.003) and women who smoke more often had a genital HPV infection (P = 0.016, Fisher's exact test). Vestibular erythema, vestibular papillomatosis, and acetowhite lesions are common in this group of healthy women without vulvar complaints.

The relationship between the Activities-specific Balance Confidence Scale and the Dynamic Gait Index in peripheral vestibular dysfunction.

PubMed

Legters, Kristine; Whitney, Susan L; Porter, Rebecca; Buczek, Frank

2005-01-01

People with vestibular dysfunction experience dizziness, vertigo and postural instability. The persistence of these symptoms may result in decreased balance confidence. The purpose of the present study was to examine the relationship between decreased balance confidence and gait dysfunction in patients with unilateral peripheral vestibular dysfunction. A retrospective review of 137 charts with the Activities-specific Balance Confidence (ABC) Scale and the Dynamic Gait Index (DGI) scores was completed. Spearman rank-order correlation analysis was performed of the total sample, by age group and by degree of vestibular weakness. A moderate correlation of r = 0.58 (p < 0.001) was found between the ABC Scale score and the DGI score in the total sample. Those with mild or moderate vestibular weakness had a correlation of r = 0.72 (p < 0.001) between the ABC Scale score and the DGI score, compared with a correlation of r = 0.48 in those with severe or total vestibular weakness. Decreased balance confidence and increased fall risk are critical issues for people with vestibular dysfunction. The effects of aging did not have a significant impact on the relationship. The correlation between balance confidence and gait dysfunction was stronger in those with mild or moderate vestibular weakness, although those with severe or total weakness were more disabled by their vestibular symptoms.

Vestibular receptors contribute to cortical auditory evoked potentials.

PubMed

Todd, Neil P M; Paillard, Aurore C; Kluk, Karolina; Whittle, Elizabeth; Colebatch, James G

2014-03-01

Acoustic sensitivity of the vestibular apparatus is well-established, but the contribution of vestibular receptors to the late auditory evoked potentials of cortical origin is unknown. Evoked potentials from 500 Hz tone pips were recorded using 70 channel EEG at several intensities below and above the vestibular acoustic threshold, as determined by vestibular evoked myogenic potentials (VEMPs). In healthy subjects both auditory mid- and long-latency auditory evoked potentials (AEPs), consisting of Na, Pa, N1 and P2 waves, were observed in the sub-threshold conditions. However, in passing through the vestibular threshold, systematic changes were observed in the morphology of the potentials and in the intensity dependence of their amplitude and latency. These changes were absent in a patient without functioning vestibular receptors. In particular, for the healthy subjects there was a fronto-central negativity, which appeared at about 42 ms, referred to as an N42, prior to the AEP N1. Source analysis of both the N42 and N1 indicated involvement of cingulate cortex, as well as bilateral superior temporal cortex. Our findings are best explained by vestibular receptors contributing to what were hitherto considered as purely auditory evoked potentials and in addition tentatively identify a new component that appears to be primarily of vestibular origin. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Immunohistochemical localization of calcium-binding proteins in the brainstem vestibular nuclei of the jaundiced Gunn rat.

PubMed

Shaia, Wayne T; Shapiro, Steven M; Heller, Andrew J; Galiani, David L; Sismanis, Aristides; Spencer, Robert F

2002-11-01

Vestibular gaze and postural abnormalities are major sequelae of neonatal hyperbilirubinemia. The sites and cellular effects of bilirubin toxicity in the brainstem vestibular pathway are not easily detected. Since altered intracellular calcium homeostasis may play a role in neuronal cell death, we hypothesized that altered expression of calcium-binding proteins may occur in brainstem vestibular nuclei of the classic animal model of bilirubin neurotoxicity. The expression of the calcium-binding proteins calbindin-D28k and parvalbumin in the brainstem vestibular pathways and cerebellum of homozygous recessive jaundiced (jj) Gunn rats was examined by light microscopy and immunohistochemistry at 18 days postnatally and compared to the findings obtained from age-matched non-jaundiced heterozygous (Nj) littermate controls. Jaundiced animals exhibited decreased parvalbumin immunoreactivity specifically in synaptic inputs to superior, medial, and inferior vestibular nuclei, and to oculomotor and trochlear nuclei, whereas the neurons retained their normal immunoreactivity. Jaundiced animals also demonstrated a decrease in calbindin expression in the lateral vestibular nuclei and a paucity of calbindin-immunoreactive synaptic endings on the somata of Deiters' neurons. The involved regions are related to the control of the vestibulo-ocular and vestibulospinal reflexes. Decreased expression of calcium-binding proteins in brainstem vestibular neurons may relate to the vestibulo-ocular and vestibulospinal dysfunction seen with clinical kernicterus, and may provide a sensitive new way to assess bilirubin toxicity in the vestibular system.

Multisensory Origin of the Subjective First-Person Perspective: Visual, Tactile, and Vestibular Mechanisms

PubMed Central

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

2013-01-01

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

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

Responses evoked by a vestibular implant providing chronic stimulation.

PubMed

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

2012-01-01

Patients with bilateral vestibular loss experience dehabilitating visual, perceptual, and postural difficulties, and an implantable vestibular prosthesis that could improve these symptoms would be of great benefit to these patients. In previous work, we have shown that a one-dimensional, unilateral canal prosthesis can improve the vestibulooccular reflex (VOR) in canal-plugged squirrel monkeys. In addition to the VOR, the potential effects of a vestibular prosthesis on more complex, highly integrative behaviors, such as the perception of head orientation and posture have remained unclear. We tested a one-dimensional, unilateral prosthesis in a rhesus monkey with bilateral vestibular loss and found that chronic electrical stimulation partially restored the compensatory VOR and also that percepts of head orientation relative to gravity were improved. However, the one-dimensional prosthetic stimulation had no clear effect on postural stability during quiet stance, but sway evoked by head-turns was modestly reduced. These results suggest that not only can the implementation of a vestibular prosthesis provide partial restitution of VOR but may also improve perception and posture in the presence of bilateral vestibular hypofunction (BVH). In this review, we provide an overview of our previous and current work directed towards the eventual clinical implementation of an implantable vestibular prosthesis.

Immediate postoperative nystagmus and vestibular symptoms after stapes surgery.

PubMed

Hirvonen, Timo P; Aalto, Heikki

2013-08-01

Vestibular disturbance is frequent, but mild even immediately after stapes surgery. Vestibular symptoms improved or disappeared quickly, and they did not correlate with nystagmus. Outpatient stapes surgery performed under local anaesthesia is a feasible approach. Vestibular symptoms are common and may prevent outpatient surgery. The time course of vestibular disturbance is unclear, and we aimed to evaluate it immediately after the operation in the recovery room. Twenty patients with otosclerosis undergoing stapedotomy were prospectively included in the study. Postoperative symptoms were collected and nystagmus was recorded with video-oculography (VOG) on average 29 min after the surgery. None of the patients had spontaneous nystagmus with gaze fixation. Nine patients (45%) had slow spontaneous horizontal nystagmus (mean slow phase velocity of 1.1°/s) in the primary position without gaze fixation. In seven of these, the nystagmus obeyed Alexander's law. Nine patients (45%) had vestibular symptoms at the end of the surgery, and four patients at the time of VOG recording. Vertigo was experienced immediately after the operation in five, floating sensation in two, and unspecific dizziness in two patients. Vestibular symptoms were mild or moderate in most patients. The occurrence of nystagmus did not correlate with vestibular symptoms (p > 0.05).

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.

[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.

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.

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.

Executive function deficits in team sport athletes with a history of concussion revealed by a visual-auditory dual task paradigm.

PubMed

Tapper, Anthony; Gonzalez, Dave; Roy, Eric; Niechwiej-Szwedo, Ewa

2017-02-01

The purpose of this study was to examine executive functions in team sport athletes with and without a history of concussion. Executive functions comprise many cognitive processes including, working memory, attention and multi-tasking. Past research has shown that concussions cause difficulties in vestibular-visual and vestibular-auditory dual-tasking, however, visual-auditory tasks have been examined rarely. Twenty-nine intercollegiate varsity ice hockey athletes (age = 19.13, SD = 1.56; 15 females) performed an experimental dual-task paradigm that required simultaneously processing visual and auditory information. A brief interview, event description and self-report questionnaires were used to assign participants to each group (concussion, no-concussion). Eighteen athletes had a history of concussion and 11 had no concussion history. The two tests involved visuospatial working memory (i.e., Corsi block test) and auditory tone discrimination. Participants completed both tasks individually, then simultaneously. Two outcome variables were measured, Corsi block memory span and auditory tone discrimination accuracy. No differences were shown when each task was performed alone; however, athletes with a history of concussion had a significantly worse performance on the tone discrimination task in the dual-task condition. In conclusion, long-term deficits in executive functions were associated with a prior history of concussion when cognitive resources were stressed. Evaluations of executive functions and divided attention appear to be helpful in discriminating participants with and without a history concussion.

Head Stability and Head-Trunk Coordination in Horseback Riders: The Contribution of Visual Information According to Expertise

PubMed Central

Olivier, Agnès; Faugloire, Elise; Lejeune, Laure; Biau, Sophie; Isableu, Brice

2017-01-01

Maintaining equilibrium while riding a horse is a challenging task that involves complex sensorimotor processes. We evaluated the relative contribution of visual information (static or dynamic) to horseback riders' postural stability (measured from the variability of segment position in space) and the coordination modes they adopted to regulate balance according to their level of expertise. Riders' perceptual typologies and their possible relation to postural stability were also assessed. Our main assumption was that the contribution of visual information to postural control would be reduced among expert riders in favor of vestibular and somesthetic reliance. Twelve Professional riders and 13 Club riders rode an equestrian simulator at a gallop under four visual conditions: (1) with the projection of a simulated scene reproducing what a rider sees in the real context of a ride in an outdoor arena, (2) under stroboscopic illumination, preventing access to dynamic visual cues, (3) in normal lighting but without the projected scene (i.e., without the visual consequences of displacement) and (4) with no visual cues. The variability of the position of the head, upper trunk and lower trunk was measured along the anteroposterior (AP), mediolateral (ML), and vertical (V) axes. We computed discrete relative phase to assess the coordination between pairs of segments in the anteroposterior axis. Visual field dependence-independence was evaluated using the Rod and Frame Test (RFT). The results showed that the Professional riders exhibited greater overall postural stability than the Club riders, revealed mainly in the AP axis. In particular, head variability was lower in the Professional riders than in the Club riders in visually altered conditions, suggesting a greater ability to use vestibular and somesthetic information according to task constraints with expertise. In accordance with this result, RFT perceptual scores revealed that the Professional riders were less dependent on the visual field than were the Club riders. Finally, the Professional riders exhibited specific coordination modes that, unlike the Club riders, departed from pure in-phase and anti-phase patterns and depended on visual conditions. The present findings provide evidence of major differences in the sensorimotor processes contributing to postural control with expertise in horseback riding. PMID:28194100

Passive motion reduces vestibular balance and perceptual responses

PubMed Central

Fitzpatrick, Richard C; Watson, Shaun R D

2015-01-01

With the hypothesis that vestibular sensitivity is regulated to deal with a range of environmental motion conditions, we explored the effects of passive whole-body motion on vestibular perceptual and balance responses. In 10 subjects, vestibular responses were measured before and after a period of imposed passive motion. Vestibulospinal balance reflexes during standing evoked by galvanic vestibular stimulation (GVS) were measured as shear reaction forces. Perceptual tests measured thresholds for detecting angular motion, perceptions of suprathreshold rotation and perceptions of GVS-evoked illusory rotation. The imposed conditioning motion was 10 min of stochastic yaw rotation (0.5–2.5 Hz ≤ 300 deg s−2) with subjects seated. This conditioning markedly reduced reflexive and perceptual responses. The medium latency galvanic reflex (300–350 ms) was halved in amplitude (48%; P = 0.011) but the short latency response was unaffected. Thresholds for detecting imposed rotation more than doubled (248%; P < 0.001) and remained elevated after 30 min. Over-estimation of whole-body rotation (30–180 deg every 5 s) before conditioning was significantly reduced (41.1 to 21.5%; P = 0.033). Conditioning reduced illusory vestibular sensations of rotation evoked by GVS (mean 113 deg for 10 s at 1 mA) by 44% (P < 0.01) and the effect persisted for at least 1 h (24% reduction; P < 0.05). We conclude that a system of vestibular sensory autoregulation exists and that this probably involves central and peripheral mechanisms, possibly through vestibular efferent regulation. We propose that failure of these regulatory mechanisms at different levels could lead to disorders of movement perception and balance control during standing. Key points Human activity exposes the vestibular organs to a wide dynamic range of motion. We aimed to discover whether the CNS regulates sensitivity to vestibular afference during exposure to ambient motion. Balance and perceptual responses to vestibular stimulation were measured before and after a 10 min period of imposed, moderate intensity, stochastic whole-body rotation. After this conditioning, vestibular balance reflexes evoked by galvanic vestibular stimulation were halved in amplitude. Conditioning doubled the thresholds for perceiving small rotations, and reduced perceptions of the amplitude of real rotations, and illusory rotation evoked by galvanic stimulation. We conclude that the CNS auto-regulates sensitivity to vestibular sensory afference and that this probably involves central and peripheral mechanisms, as might arise from vestibular efferent regulation. Failure of these regulatory mechanisms at different levels could lead to disorders of movement perception and balance control during standing. PMID:25809702

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.

Use of Virtual Reality Tools for Vestibular Disorders Rehabilitation: A Comprehensive Analysis.

PubMed

Bergeron, Mathieu; Lortie, Catherine L; Guitton, Matthieu J

2015-01-01

Classical peripheral vestibular disorders rehabilitation is a long and costly process. While virtual reality settings have been repeatedly suggested to represent possible tools to help the rehabilitation process, no systematic study had been conducted so far. We systematically reviewed the current literature to analyze the published protocols documenting the use of virtual reality settings for peripheral vestibular disorders rehabilitation. There is an important diversity of settings and protocols involving virtual reality settings for the treatment of this pathology. Evaluation of the symptoms is often not standardized. However, our results unveil a clear effect of virtual reality settings-based rehabilitation of the patients' symptoms, assessed by objectives tools such as the DHI (mean decrease of 27 points), changing symptoms handicap perception from moderate to mild impact on life. Furthermore, we detected a relationship between the duration of the exposure to virtual reality environments and the magnitude of the therapeutic effects, suggesting that virtual reality treatments should last at least 150 minutes of cumulated exposure to ensure positive outcomes. Virtual reality offers a pleasant and safe environment for the patient. Future studies should standardize evaluation tools, document putative side effects further, compare virtual reality to conventional physical therapy, and evaluate economical costs/benefits of such strategies.

Use of Virtual Reality Tools for Vestibular Disorders Rehabilitation: A Comprehensive Analysis

PubMed Central

Bergeron, Mathieu; Lortie, Catherine L.; Guitton, Matthieu J.

2015-01-01

Classical peripheral vestibular disorders rehabilitation is a long and costly process. While virtual reality settings have been repeatedly suggested to represent possible tools to help the rehabilitation process, no systematic study had been conducted so far. We systematically reviewed the current literature to analyze the published protocols documenting the use of virtual reality settings for peripheral vestibular disorders rehabilitation. There is an important diversity of settings and protocols involving virtual reality settings for the treatment of this pathology. Evaluation of the symptoms is often not standardized. However, our results unveil a clear effect of virtual reality settings-based rehabilitation of the patients' symptoms, assessed by objectives tools such as the DHI (mean decrease of 27 points), changing symptoms handicap perception from moderate to mild impact on life. Furthermore, we detected a relationship between the duration of the exposure to virtual reality environments and the magnitude of the therapeutic effects, suggesting that virtual reality treatments should last at least 150 minutes of cumulated exposure to ensure positive outcomes. Virtual reality offers a pleasant and safe environment for the patient. Future studies should standardize evaluation tools, document putative side effects further, compare virtual reality to conventional physical therapy, and evaluate economical costs/benefits of such strategies. PMID:26556560

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

Cell proliferation during hair cell regeneration induced by Math1 in vestibular epithelia in vitro

PubMed Central

Huang, Yi-bo; Ma, Rui; Yang, Juan-mei; Han, Zhao; Cong, Ning; Gao, Zhen; Ren, Dongdong; Wang, Jing; Chi, Fang-lu

2018-01-01

Hair cell regeneration is the fundamental method of correcting hearing loss and balance disorders caused by hair cell damage or loss. How to promote hair cell regeneration is a hot focus in current research. In mammals, cochlear hair cells cannot be regenerated and few vestibular hair cells can be renewed through spontaneous regeneration. However, Math1 gene transfer allows a few inner ear cells to be transformed into hair cells in vitro or in vivo. Hair cells can be renewed through two possible means in birds: supporting cell differentiation and transdifferentiation with or without cell division. Hair cell regeneration is strongly associated with cell proliferation. Therefore, this study explored the relationship between Math1-induced vestibular hair cell regeneration and cell division in mammals. The mouse vestibule was isolated to harvest vestibular epithelial cells. Ad-Math1-enhanced green fluorescent protein (EGFP) was used to track cell division during hair cell transformation. 5-Bromo-2′-deoxyuridine (BrdU) was added to track cell proliferation at various time points. Immunocytochemistry was utilized to determine cell differentiation and proliferation. Results demonstrated that when epithelial cells were in a higher proliferative stage, more of these cells differentiated into hair cells by Math1 gene transfer. However, in the low proliferation stage, no BrdU-positive cells were seen after Math1 gene transfer. Cell division always occurred before Math1 transfection but not during or after Math1 transfection, when cells were labeled with BrdU before and after Ad-Math1-EGFP transfection. These results confirm that vestibular epithelial cells with high proliferative potential can differentiate into new hair cells by Math1 gene transfer, but this process is independent of cell proliferation. PMID:29623936

Culture media-based selection of endothelial cells, pericytes, and perivascular-resident macrophage-like melanocytes from the young mouse vestibular system.

PubMed

Zhang, Jinhui; Chen, Songlin; Cai, Jing; Hou, Zhiqiang; Wang, Xiaohan; Kachelmeier, Allan; Shi, Xiaorui

2017-03-01

The vestibular blood-labyrinth barrier (BLB) is comprised of perivascular-resident macrophage-like melanocytes (PVM/Ms) and pericytes (PCs), in addition to endothelial cells (ECs) and basement membrane (BM), and bears strong resemblance to the cochlear BLB in the stria vascularis. Over the past few decades, in vitro cell-based models have been widely used in blood-brain barrier (BBB) and blood-retina barrier (BRB) research, and have proved to be powerful tools for studying cell-cell interactions in their respective organs. Study of both the vestibular and strial BLB has been limited by the unavailability of primary culture cells from these barriers. To better understand how barrier component cells interact in the vestibular system to control BLB function, we developed a novel culture medium-based method for obtaining EC, PC, and PVM/M primary cells from tiny explants of the semicircular canal, sacculus, utriculus, and ampullae tissue of young mouse ears at post-natal age 8-12 d. Each phenotype is grown in a specific culture medium which selectively supports the phenotype in a mixed population of vestibular cell types. The unwanted phenotypes do not survive passaging. The protocol does not require additional equipment or special enzyme treatment. The harvesting process takes less than 2 h. Primary cell types are generated within 7-10 d. The primary culture ECs, PCs, and PVM/M shave consistent phenotypes more than 90% pure after two passages (∼ 3 weeks). The highly purified primary cell lines can be used for studying cell-cell interactions, barrier permeability, and angiogenesis. Copyright © 2017 Elsevier B.V. All rights reserved.

Response of vestibular-nerve afferents to active and passive rotations under normal conditions and after unilateral labyrinthectomy.

PubMed

Sadeghi, Soroush G; Minor, Lloyd B; Cullen, Kathleen E

2007-02-01

We investigated the possible contribution of signals carried by vestibular-nerve afferents to long-term processes of vestibular compensation after unilateral labyrinthectomy. Semicircular canal afferents were recorded from the contralesional nerve in three macaque monkeys before [horizontal (HC) = 67, anterior (AC) = 66, posterior (PC) = 50] and 1-12 mo after (HC = 192, AC = 86, PC = 57) lesion. Vestibular responses were evaluated using passive sinusoidal rotations with frequencies of 0.5-15 Hz (20-80 degrees /s) and fast whole-body rotations reaching velocities of 500 degrees /s. Sensitivities to nonvestibular inputs were tested by: 1) comparing responses during active and passive head movements, 2) rotating the body with the head held stationary to activate neck proprioceptors, and 3) encouraging head-restrained animals to attempt to make head movements that resulted in the production of neck torques of < or =2 Nm. Mean resting discharge rate before and after the lesion did not differ for the regular, D (dimorphic)-irregular, or C (calyx)-irregular afferents. In response to passive rotations, afferents showed no change in sensitivity and phase, inhibitory cutoff, and excitatory saturation after unilateral labyrinthectomy. Moreover, head sensitivities were similar during voluntary and passive head rotations and responses were not altered by neck proprioceptive or efference copy signals before or after the lesion. The only significant change was an increase in the proportion of C-irregular units postlesion, accompanied by a decrease in the proportion of regular afferents. Taken together, our findings show that changes in response properties of the vestibular afferent population are not likely to play a major role in the long-term changes associated with compensation after unilateral labyrinthectomy.

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/

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.

Differential effects of labyrinthine dysfunction on distance and direction during blindfolded walking of a triangular path.

PubMed

Glasauer, S; Amorim, M-A; Viaud-Delmon, I; Berthoz, A

2002-08-01

While we walk through the environment, we constantly receive inputs from different sensory systems. For us to accomplish a given task, for example to reach a target location, the sensory information has to be integrated to update our knowledge of self-position and self-orientation with respect to the target so that we can correctly plan and perform the remaining trajectory. As has been shown previously, vestibular information plays a minor role in the performance of linear goal-directed locomotion when walking blindfolded toward a previously seen target within a few meters. The present study extends the question of whether vestibular information is a requirement for goal-directed locomotion by studying a more complex task that also involves rotation: walking a triangular path. Furthermore, studying this task provides information about how we walk a given trajectory, how we move around corners, and whether we are able to return to the starting point. Seven young male, five labyrinthine-defective (LD) and five age- and gender-matched control subjects were asked to walk a previously seen triangular path, which was marked on the ground, first without vision (EC) and then with vision (EO). Each subject performed three clockwise (CW) and three counterclockwise (CCW) walks under the EC condition and one CW and CCW walk under the EO condition. The movement of the subjects was recorded by means of a 3D motion analysis system. Analysis of the data showed that LD subjects had, in the EC condition, a significantly larger final arrival error, which was due to increased directional errors during the turns. However, there was no difference between the groups as regards the overall path length walked. This shows that LD subjects were able to plan and execute the given trajectory without vision, but failed to turn correctly around the corners. Hence, the results demonstrate that vestibular information enhances the ability to perform a planned trajectory incorporating whole body rotations when no visual feedback is available.

Increased independence and decreased vertigo after vestibular rehabilitation.

PubMed

Cohen, Helen S; Kimball, Kay T

2003-01-01

We sought to determine the effectiveness in decreasing some symptoms, such as vertigo, and increasing performance of daily life skills after vestibular rehabilitation. Patients who had chronic vertigo due to peripheral vestibular impairments were seen at a tertiary care center. They were referred for vestibular rehabilitation and were assessed on vertigo intensity and frequency with the use of the Vertigo Symptom Scale, the Vertigo Handicap Questionnaire, the Vestibular Disorders Activities of Daily Living Scale, and the Dizziness Handicap Inventory. They were then randomly assigned to 1 of 3 home program treatment groups. Vertigo decreased and independence in activities of daily living improved significantly. Improvement was not affected by age, gender, or history of vertigo. For many patients a simple home program of vestibular habituation head movement exercises is related to reduction in symptoms and increasing independence in activities of daily living.

Development and regeneration of vestibular hair cells in mammals.

PubMed

Burns, Joseph C; Stone, Jennifer S

2017-05-01

Vestibular sensation is essential for gaze stabilization, balance, and perception of gravity. The vestibular receptors in mammals, Type I and Type II hair cells, are located in five small organs in the inner ear. Damage to hair cells and their innervating neurons can cause crippling symptoms such as vertigo, visual field oscillation, and imbalance. In adult rodents, some Type II hair cells are regenerated and become re-innervated after damage, presenting opportunities for restoring vestibular function after hair cell damage. This article reviews features of vestibular sensory cells in mammals, including their basic properties, how they develop, and how they are replaced after damage. We discuss molecules that control vestibular hair cell regeneration and highlight areas in which our understanding of development and regeneration needs to be deepened. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Regenerative therapy for vestibular disorders using human induced pluripotent stem cells (iPSCs): neural differentiation of human iPSC-derived neural stem cells after in vitro transplantation into mouse vestibular epithelia.

PubMed

Taura, Akiko; Nakashima, Noriyuki; Ohnishi, Hiroe; Nakagawa, Takayuki; Funabiki, Kazuo; Ito, Juichi; Omori, Koichi

2016-10-01

Vestibular ganglion cells, which convey sense of motion from vestibular hair cells to the brainstem, are known to degenerate with aging and after vestibular neuritis. Thus, regeneration of vestibular ganglion cells is important to aid in the recovery of balance for associated disorders. The present study derived hNSCs from induced pluripotent stem cells (iPSCs) and transplanted these cells into mouse utricle tissues. After a 7-day co-culture period, histological and electrophysiological examinations of transplanted hNSCs were performed. Injected hNSC-derived cells produced elongated axon-like structures within the utricle tissue that made contact with vestibular hair cells. A proportion of hNSC-derived cells showed spontaneous firing activities, similar to those observed in cultured mouse vestibular ganglion cells. However, hNSC-derived cells around the mouse utricle persisted as immature neurons or occasionally differentiated into putative astrocytes. Moreover, electrophysiological examination showed hNSC-derived cells around utricles did not exhibit any obvious spontaneous firing activities. Injected human neural stem cells (hNSCs) showed signs of morphological maturation including reconnection to denervated hair cells and partial physiological maturation, suggesting hNSC-derived cells possibly differentiated into neurons.

Examining the Effect of Age on Visual-Vestibular Self-Motion Perception Using a Driving Paradigm.

PubMed

Ramkhalawansingh, Robert; Keshavarz, Behrang; Haycock, Bruce; Shahab, Saba; Campos, Jennifer L

2017-05-01

Previous psychophysical research has examined how younger adults and non-human primates integrate visual and vestibular cues to perceive self-motion. However, there is much to be learned about how multisensory self-motion perception changes with age, and how these changes affect performance on everyday tasks involving self-motion. Evidence suggests that older adults display heightened multisensory integration compared with younger adults; however, few previous studies have examined this for visual-vestibular integration. To explore age differences in the way that visual and vestibular cues contribute to self-motion perception, we had younger and older participants complete a basic driving task containing visual and vestibular cues. We compared their performance against a previously established control group that experienced visual cues alone. Performance measures included speed, speed variability, and lateral position. Vestibular inputs resulted in more precise speed control among older adults, but not younger adults, when traversing curves. Older adults demonstrated more variability in lateral position when vestibular inputs were available versus when they were absent. These observations align with previous evidence of age-related differences in multisensory integration and demonstrate that they may extend to visual-vestibular integration. These findings may have implications for vehicle and simulator design when considering older users.

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

PubMed

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

2011-12-01

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

Vestibular Rehabilitation Therapy: Review of Indications, Mechanisms, and Key Exercises

PubMed Central

Song, Hyun Seok; Kim, Ji Soo

2011-01-01

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

Clinical application of vestibular evoked myogenic potential (VEMP).

PubMed

Murofushi, Toshihisa

2016-08-01

The author reviewed clinical aspects of vestibular evoked myogenic potentials (VEMPs). Now two types of VEMPs are available. The first one is cervical VEMP, which is recorded in the sternocleidomastoid muscle and predominantly reflects sacculo-collic reflex. The other is ocular VEMP, which is usually recorded below the lower eye lid and predominantly reflects utriculo-ocular reflex. VEMPs play important roles not only for assessment of common vestibular diseases but also for establishment of new clinical entities. Clinical application in Meniere's disease, vestibular neuritis, benign paroxysmal positional vertigo, vestibular migraine, idiopathic otolithic vertigo, and central vertigo/dizziness was reviewed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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.

Calcitonin gene-related Peptide and choline acetyltransferase colocalization in the human vestibular periphery.

PubMed

Popper, Paul; Ishiyama, Akira; Lopez, Ivan; Wackym, Phillip A

2002-01-01

Within the vestibular system, calcitonin gene-related peptide (CGRP) has been localized in the efferent terminals and their brainstem neuronal cell bodies in several animal models. Presently, very few studies have verified these findings in the vestibular system in adult primates or humans. CGRP immunoreactivity (CGRPi) and its colocalization with choline acetyltransferase immunoreactivity (ChATi) in human vestibular end organs and Scarpa's ganglion were studied using polyclonal antibodies against CGRP and ChAT, at the light-microscopic level. The CGRPi axons ramified to produce numerous CGRPi terminals throughout the neurosensory epithelium of the maculae and cristae, primarily in the basal and midbasal areas. Numerous CGRPi efferent terminals made contact with both type II vestibular hair cells and the afferent chalices surrounding type I vestibular hair cells. All CGRP immunoreactive fibers also exhibited ChATi. As in the animal models, no CGRPi was found within Scarpa's ganglion. This study provides evidence for CGRPi in the human vestibular periphery and validates the biomedical relevance of the current animal models. Copyright 2002 S. Karger AG, Basel

Chronic inflammatory demyelinating polyneuropathy: evaluation of the vestibular system with cervical and ocular vestibular evoked myogenic potentials.

PubMed

Magliulo, Giuseppe; Iannella, Giannicola; Manno, Alessandra; Libonati, Laura; Onesti, Emanuela; Vestri, Annarita; Fegatelli, Danilo Alunni; Angeletti, Diletta; Pace, Annalisa; Gulotta, Giampiero; Gagliardi, Silvia; Inghilleri, Maurizio

2018-06-01

To investigate the possibility of vestibular damage in a group of patients suffering from chronic inflammatory demyelinating polyneuropathy (CIDP) using a diagnostic protocol including the caloric test, C-VEMPs and O-VEMPs. Twenty patients suffering from CIDP (mean age 58.5 years, range 33-80 years; 4 women and 16 men) were investigated. To assess any eventual audio-vestibular involvement, all patients of the study underwent pure tone audiometry, Fitzgerald-Hallpike caloric vestibular test, C-VEMPs and O-VEMPs. In 11 patients with CIDP values of both O-VEMPs and C-VEMPs were either absent or abnormal. An absent trace at O-VEMPs testing occurred in 36% of these pathological patients, whereas an increase of n10 latency and amplitude was present in the other 64% . A specific diagnostic protocol including the caloric test, C-VEMPS, O-VEMPS, could be useful when employed for identifying vestibular damage in CIDP patients.

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.

ELECTROMYOGRAPHIC ACTIVITY OF STERNOCLEIDOMASTOID AND MASTICATORY MUSCLES IN PATIENTS WITH VESTIBULAR LESIONS

PubMed Central

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

2008-01-01

This study evaluated the electromyographic characteristics of masticatory and neck muscles in subjects with vestibular lesions. Surface electromyography of the masseter, temporalis and sternocleidomastoid muscles was performed in 19 patients with Ménière's disease, 12 patients with an acute peripheral vestibular lesion, and 19 control subjects matched for sex and age. During maximum voluntary clenching, patients with peripheral vestibular lesions had the highest co-contraction of the sternocleidomastoid muscle (analysis of covariance, p=0.02), the control subjects had the smallest values, and the patients with Ménière's disease had intermediate values. The control subjects had larger standardized muscle activities than the other patient groups (p=0.001). In conclusion, during maximum voluntary tooth clenching, patients with vestibular alterations have both more active neck muscles, and less active masticatory muscles than normal controls. Results underline the importance of a more inclusive craniocervical assessment of patients with vestibular lesions. PMID:19082397

Hyperventilation-induced nystagmus in a large series of vestibular patients.

PubMed

Califano, L; Melillo, M G; Vassallo, A; Mazzone, S

2011-02-01

The Hyperventilation Test is widely used in the "bed-side examination" of vestibular patients. It can either activate a latent nystagmus in central or peripheral vestibular diseases or it can interact with a spontaneous nystagmus, by reducing it or increasing it. Aims of this study were to determine the incidence, patterns and temporal characteristics of Hyperventilation-induced nystagmus in patients suffering from vestibular diseases, as well as its contribution to the differential diagnosis between vestibular neuritis and neuroma of the 8(th) cranial nerve, and its behaviour in some central vestibular diseases. The present study includes 1202 patients featuring, at vestibular examination, at least one sign of vestibular system disorders or patients diagnosed with a "Migraine-related vertigo" or "Chronic subjective dizziness". The overall incidence of Hyperventilation-induced nystagmus was 21.9%. It was detected more frequently in retrocochlear vestibular diseases rather than in end-organ vestibular diseases: 5.3% in Paroxysmal Positional Vertigo, 37.1% in Menière's disease, 37.6% in compensated vestibular neuritis, 77.2% in acute vestibular neuritis and 91.7% in neuroma of the 8(th) cranial nerve. In acute vestibular neuritis, three HVIN patterns were observed: Paretic pattern: temporary enhancement of the spontaneous nystagmus; Excitatory pattern: temporary inhibition of the spontaneous nystagmus; Strong excitatory pattern: temporary inversion of the spontaneous nystagmus. Excitatory patterns proved to be time-dependent in that they disappeared and were replaced by the paretic pattern over a period of maximum 18 days since the beginning of the disorder. In acoustic neuroma, Hyperventilation-induced nystagmus was frequently observed (91.7%), either in the form of an excitatory pattern (fast phases towards the affected site) or in the form of a paretic pattern (fast phases towards the healthy side). The direction of the nystagmus is only partially related to tumour size, whereas other mechanisms, such as demyelination or a break in nerve fibres, might have an important role in triggering the situation. Hyperventilation-induced nystagmus has frequently been detected in cases of demyelinating diseases and in cerebellar diseases: in multiple sclerosis, hyperventilation inhibits a central type of spontaneous nystagmus or evokes nystagmus in 75% of patients; in cerebellar diseases, hyperventilation evokes or enhances a central spontaneous nystagmus in 72.7% of patients. In conclusion the Hyperventilation Test can provide patterns of oculomotor responses that indicate a diagnostic investigation through cerebral magnetic resonance imaging enhanced by gadolinium, upon suspicion of neuroma of the 8(th) cranial nerve or of a central disease. In our opinion, however, Hyperventilation-induced nystagmus always needs to be viewed within the more general context of a complete examination of the vestibular and acoustic system.

Three-dimensional head-mounted gaming task procedure maximizes effects of vestibular rehabilitation in unilateral vestibular hypofunction: a randomized controlled pilot trial.

PubMed

Micarelli, Alessandro; Viziano, Andrea; Augimeri, Ivan; Micarelli, Domenico; Alessandrini, Marco

2017-12-01

Considering the emerging advantages related to virtual reality implementation in clinical rehabilitation, the aim of the present study was to discover possible (i) improvements achievable in unilateral vestibular hypofunction patients using a self-assessed head-mounted device (HMD)-based gaming procedure when combined with a classical vestibular rehabilitation protocol (HMD group) as compared with a group undergoing only vestibular rehabilitation and (ii) HMD procedure-related side effects. Therefore, 24 vestibular rehabilitation and 23-matched HMD unilateral vestibular hypofunction individuals simultaneously underwent a 4-week rehabilitation protocol. Both otoneurological measures (vestibulo-ocular reflex gain and postural arrangement by studying both posturography parameters and spectral values of body oscillation) and performance and self-report measures (Italian Dizziness Handicap Inventory; Activities-specific Balance Confidence scale; Zung Instrument for Anxiety Disorders, Dynamic Gait Index; and Simulator Sickness Questionnaire) were analyzed by means of a between-group/within-subject analysis of variance model. A significant post-treatment between-effect was found, and the HMD group demonstrated an overall improvement in vestibulo-ocular reflex gain on the lesional side, in posturography parameters, in low-frequency spectral domain, as well as in Italian Dizziness Handicap Inventory and Activities-specific Balance Confidence scale scores. Meanwhile, Simulator Sickness Questionnaire scores demonstrated a significant reduction in symptoms related to experimental home-based gaming tasks during the HMD procedure. Our findings revealed the possible advantages of HMD implementation in vestibular rehabilitation, suggesting it as an innovative, self-assessed, low-cost, and compliant tool useful in maximizing vestibular rehabilitation outcomes.

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

Vestibular-somatosensory convergence in head movement control during locomotion after long-duration space flight.

PubMed

Mulavara, A P; Ruttley, T; Cohen, H S; Peters, B T; Miller, C; Brady, R; Merkle, L; Bloomberg, J J

2012-01-01

Space flight causes astronauts to be exposed to adaptation in both the vestibular and body load-sensing somatosensory systems. The goal of these studies was to examine the contributions of vestibular and body load-sensing somatosensory influences on vestibular mediated head movement control during locomotion after long-duration space flight. Subjects walked on a motor driven treadmill while performing a gaze stabilization task. Data were collected from three independent subject groups that included bilateral labyrinthine deficient (LD) patients, normal subjects before and after 30 minutes of 40% bodyweight unloaded treadmill walking, and astronauts before and after long-duration space flight. Motion data from the head and trunk segments were used to calculate the amplitude of angular head pitch and trunk vertical translation movement while subjects performed a gaze stabilization task, to estimate the contributions of vestibular reflexive mechanisms in head pitch movements. Exposure to unloaded locomotion caused a significant increase in head pitch movements in normal subjects, whereas the head pitch movements of LD patients were significantly decreased. This is the first evidence of adaptation of vestibular mediated head movement responses to unloaded treadmill walking. Astronaut subjects showed a heterogeneous response of both increases and decreases in the amplitude of head pitch movement. We infer that body load-sensing somatosensory input centrally modulates vestibular input and can adaptively modify vestibularly mediated head-movement control during locomotion. Thus, space flight may cause central adaptation of the converging vestibular and body load-sensing somatosensory systems leading to alterations in head movement control.

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.

MICROLESIONS OF THE INFERIOR OLIVE REDUCE VESTIBULAR MODULATION OF PURKINJE CELL COMPLEX AND SIMPLE SPIKES IN MOUSE CEREBELLUM

PubMed Central

Barmack, N.H.; Yakhnitsa, V.

2011-01-01

Cerebellar Purkinje cells have two distinct action potentials: Complex spikes (CSs) are evoked by single climbing fibers that originate from the contralateral inferior olive. Simple spikes (SSs) are often ascribed to mossy fiber---granule cell---parallel fiber inputs to Purkinje cells. Although generally accepted, this view lacks experimental support. Vestibular stimulation independently activates primary afferent mossy fibers and tertiary afferent climbing fibers that project to theuvula-nodulus (folia 8-10). CSs and SSs normally discharge antiphasically during sinusoidal roll-tilt. When CSs increase, SSs decrease. We tested the relative independence of these pathways in mice by making electrolytic microlesions of the two inferior olivary nuclei from which vestibular climbing fibers originate; the β-nucleus and dorsomedial cell column (DMCC). This reduced vestibular climbing fiber signaling to the contralateral folia 8-10, while leaving intact vestibular primary and secondary afferent mossy fibers. We recorded from Purkinje cells and interneurons in folia 8-10, identified by juxtacellular labeling with neurobiotin. Microlesions of the inferior olive increased the spontaneous discharge of SSs in contralateral folia 8-10, but blocked their modulation during vestibular stimulation. The vestibularly-evoked discharge of excitatory cerebellar interneurons (granule cells and unipolar brush cells) was not modified by olivary microlesions. The modulated discharge of stellate cells, but not Golgi cells was reduced by olivary microlesions. We conclude that vestibular modulation of CSs and SSs depends on intact climbing fibers. The absence of vestibularly-modulated SSs following olivary microlesions reflects the loss of climbing fiber-evoked stellate cell discharge. PMID:21734274

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.

What can posturography tell us about vestibular function?

NASA Technical Reports Server (NTRS)

Black, F. O.

2001-01-01

Patients with balance disorders want answers to the following basic questions: (1) What is causing my problem? and (2) What can be done about my problem? Information to fully answer these questions must include status of both sensory and motor components of the balance control systems. Computerized dynamic posturography (CDP) provides quantitative assessment of both sensory and motor components of postural control along with how the sensory inputs to the brain interact. This paper reviews the scientific basis and clinical applications of CDP. Specifically, studies describing the integration of vestibular inputs with other sensory systems for postural control are briefly summarized. Clinical applications, including assessment, rehabilitation, and management are presented. Effects of aging on postural control along with prevention and management strategies are discussed.

Comparative assessment of prognosis of the stop stimulus and trapezoidal rotation programs

NASA Technical Reports Server (NTRS)

Grigorova, V. K.; Popov, V. K.; Todorova, V. S.

1980-01-01

For prognosis of the diagnostic possibilities of the stop stimulus and trapezoidal rotation programs with respect to the nystagmus response, 24 healthy young persons with normal auditory and vestibular analysers were studied experimentally. The trapezoidal program more accurately reflects the function and tone balance of the vestibular system than the stop stimulus program and causes the subject no unpleasant sensations during the study. Some optimum couples, acceleration and armchair rotation rate, necessary for effective deviation of the cupuloendolymphatic system were determined. The maximum angular velocity of the slow nystagmus component was more informative than nystagmus duration. The trapezoidal program is recommended for otoneurological practice and the maximum angular velocity of the slow nystagmus component as the basic index.

Fifth Symposium on the Role of the Vestibular Organs in Space Exploration

NASA Technical Reports Server (NTRS)

1973-01-01

Vestibular problems of manned space flight are investigated for weightlessness and reduced gravity conditions with emphasis on space station development. Intensive morphological studies on the vestibular system and its central nervous system connections are included.

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.

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 History and Evolution of Surgery on the Vestibular Labyrinth.

PubMed

Naples, James G; Eisen, Marc D

2016-11-01

The history of surgery on the vestibular labyrinth is rich but sparsely documented in the literature. The story begins over a century ago with the labyrinthectomy in an era that consisted exclusively of ablative surgery for infection or vertigo. Improved understanding of vestibular physiology and pathology produced an era of selective ablation and hearing preservation that includes semicircular canal occlusion for benign paroxysmal positional vertigo. An era of restoration began with a discovery of superior semicircular canal dehiscence and its repair. The final era of vestibular replacement is upon us as the possibility of successful prosthetic vestibular implantation becomes reality. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

[Vestibular paroxismia].

PubMed

Likhachev, S A; Mar'enko, I P; Antonenko, A I

2013-01-01

The objective of the present publication was to demonstrate a clinical case of peripheral vestibular paroxismia verified in a woman with the help of the MRI technique. Vestibular paroxismia is a relatively rare disease manifested in such characteristic signs and symptoms as sudden and short-lived episodes of dizziness, unstable gait, and the concomitant vegetative disorders accompanied as a rule by tympanophonia, impairment of hearing, and falls. In typical cases, the duration of such episodes varies from several minutes to a few days. A case of vestibular paroxismia associated with the lesion in the peripheral section of the vestibular system is described; it was caused by compression of the nerve by a blood vessel as shown by means of magnetic resonance imaging of cranial nerves.

Vestibular schwannomas: Accuracy of tumor volume estimated by ice cream cone formula using thin-sliced MR images

PubMed Central

Ho, Hsing-Hao; Li, Ya-Hui; Lee, Jih-Chin; Wang, Chih-Wei; Yu, Yi-Lin; Hueng, Dueng-Yuan; Hsu, Hsian-He

2018-01-01

Purpose We estimated the volume of vestibular schwannomas by an ice cream cone formula using thin-sliced magnetic resonance images (MRI) and compared the estimation accuracy among different estimating formulas and between different models. Methods The study was approved by a local institutional review board. A total of 100 patients with vestibular schwannomas examined by MRI between January 2011 and November 2015 were enrolled retrospectively. Informed consent was waived. Volumes of vestibular schwannomas were estimated by cuboidal, ellipsoidal, and spherical formulas based on a one-component model, and cuboidal, ellipsoidal, Linskey’s, and ice cream cone formulas based on a two-component model. The estimated volumes were compared to the volumes measured by planimetry. Intraobserver reproducibility and interobserver agreement was tested. Estimation error, including absolute percentage error (APE) and percentage error (PE), was calculated. Statistical analysis included intraclass correlation coefficient (ICC), linear regression analysis, one-way analysis of variance, and paired t-tests with P < 0.05 considered statistically significant. Results Overall tumor size was 4.80 ± 6.8 mL (mean ±standard deviation). All ICCs were no less than 0.992, suggestive of high intraobserver reproducibility and high interobserver agreement. Cuboidal formulas significantly overestimated the tumor volume by a factor of 1.9 to 2.4 (P ≤ 0.001). The one-component ellipsoidal and spherical formulas overestimated the tumor volume with an APE of 20.3% and 29.2%, respectively. The two-component ice cream cone method, and ellipsoidal and Linskey’s formulas significantly reduced the APE to 11.0%, 10.1%, and 12.5%, respectively (all P < 0.001). Conclusion The ice cream cone method and other two-component formulas including the ellipsoidal and Linskey’s formulas allow for estimation of vestibular schwannoma volume more accurately than all one-component formulas. PMID:29438424

Directional asymmetries and age effects in human self-motion perception.

PubMed

Roditi, Rachel E; Crane, Benjamin T

2012-06-01

Directional asymmetries in vestibular reflexes have aided the diagnosis of vestibular lesions; however, potential asymmetries in vestibular perception have not been well defined. This investigation sought to measure potential asymmetries in human vestibular perception. Vestibular perception thresholds were measured in 24 healthy human subjects between the ages of 21 and 68 years. Stimuli consisted of a single cycle of sinusoidal acceleration in a single direction lasting 1 or 2 s (1 or 0.5 Hz), delivered in sway (left-right), surge (forward-backward), heave (up-down), or yaw rotation. Subject identified self-motion directions were analyzed using a forced choice technique, which permitted thresholds to be independently determined for each direction. Non-motion stimuli were presented to measure possible response bias. A significant directional asymmetry in the dynamic response occurred in 27% of conditions tested within subjects, and in at least one type of motion in 92% of subjects. Directional asymmetries were usually consistent when retested in the same subject but did not occur consistently in one direction across the population with the exception of heave at 0.5 Hz. Responses during null stimuli presentation suggested that asymmetries were not due to biased guessing. Multiple models were applied and compared to determine if sensitivities were direction specific. Using Akaike information criterion, it was found that the model with direction specific sensitivities better described the data in 86% of runs when compared with a model that used the same sensitivity for both directions. Mean thresholds for yaw were 1.3±0.9°/s at 0.5 Hz and 0.9±0.7°/s at 1 Hz and were independent of age. Thresholds for surge and sway were 1.7±0.8 cm/s at 0.5 Hz and 0.7±0.3 cm/s at 1.0 Hz for subjects <50 and were significantly higher in subjects >50 years old. Heave thresholds were higher and were independent of age.

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.

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

Unilateral vestibular schwannoma in a patient with schwannomatosis in the absence of LZTR1 mutation

PubMed Central

Mehta, Gautam U.; Feldman, Michael J.; Wang, Herui; Ding, Dale; Chittiboina, Prashant

2016-01-01

The presence of vestibular schwannomas has long been considered an exclusion criterion for the diagnosis of schwannomatosis. Recently, 2 cases of vestibular schwannoma were reported in patients with schwannomatosis, leading to a revision of the diagnostic criteria for this genetic disorder. Overall, the relative infrequency of vestibular schwannomas in schwannomatosis is unexplained, and the genetics of this uncommon phenomenon have not been described. The authors report on a family with clinical manifestations consistent with schwannomatosis, including 4 affected members, that was identified as having an affected member harboring a unilateral cerebellopontine angle mass with extension into the internal auditory canal. Radiologically, this mass was consistent with a vestibular schwannoma and resulted in a symptomatic change in ipsilateral hearing (word recognition 86% at 52 dB) and increased latency of the wave I–V interval on auditory brainstem response testing. The patient was found to be negative for a germline mutation of NF2 and LZTR1, and her affected mother was found to harbor neither NF2 nor SMARCB1 mutations on genetic testing. Although vestibular schwannomas have been classically considered to not occur in the setting of schwannomatosis, this patient with schwannomatosis and a vestibular schwannoma further confirms that schwannomas can occur on the vestibular nerve in this syndrome. Further, this is the first such case found to be negative for a mutation on the LZTR1 gene. PMID:26848914

Unilateral vestibular schwannoma in a patient with schwannomatosis in the absence of LZTR1 mutation.

PubMed

Mehta, Gautam U; Feldman, Michael J; Wang, Herui; Ding, Dale; Chittiboina, Prashant

2016-12-01

The presence of vestibular schwannomas has long been considered an exclusion criterion for the diagnosis of schwannomatosis. Recently, 2 cases of vestibular schwannoma were reported in patients with schwannomatosis, leading to a revision of the diagnostic criteria for this genetic disorder. Overall, the relative infrequency of vestibular schwannomas in schwannomatosis is unexplained, and the genetics of this uncommon phenomenon have not been described. The authors report on a family with clinical manifestations consistent with schwannomatosis, including 4 affected members, that was identified as having an affected member harboring a unilateral cerebellopontine angle mass with extension into the internal auditory canal. Radiologically, this mass was consistent with a vestibular schwannoma and resulted in a symptomatic change in ipsilateral hearing (word recognition 86% at 52 dB) and increased latency of the wave I-V interval on auditory brainstem response testing. The patient was found to be negative for a germline mutation of NF2 and LZTR1, and her affected mother was found to harbor neither NF2 nor SMARCB1 mutations on genetic testing. Although vestibular schwannomas have been classically considered to not occur in the setting of schwannomatosis, this patient with schwannomatosis and a vestibular schwannoma further confirms that schwannomas can occur on the vestibular nerve in this syndrome. Further, this is the first such case found to be negative for a mutation on the LZTR1 gene.

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.

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 Response to Electrical Stimulation of the Otolith Organs. Implications in the Development of A Vestibular Implant for the Improvement of the Sensation of Gravitoinertial Accelerations.

PubMed

Ramos de Miguel, Angel; Falcon Gonzalez, Juan Carlos; Ramos Macias, Angel

2017-08-01

Electrical stimulation of the utricular and saccular portions of the vestibular nerve improves stability in patients suffering from vestibular dysfunction. The main objective of this study was to evaluate a new technique, vestibular response telemetry (VRT), for measuring the electrically evoked vestibular compound action potential (saccular and utricular) after stimulating the otolith organ (saccular and utricular) in adults. This study used evidence that the otolith organ can be electrically stimulated in order to develop a new vestibular implant design to improve the sensation of gravitoinertial acceleration. Four adult patients were evaluated by using a variety of measurement procedures with novel VRT software. VRT values were obtained by stimulating with three full-band Nucleus CI24RE (ST) electrodes. Specific stimuli were used. Simultaneously, electrical ocular vestibular evoked myogenic potentials (eoVEMPs) were recorded in the contralateral side. Electrically evoked compound action potentials were obtained in 10 of the 12 electrodes tested, and eoVEMPs were recorded when VRT was present. In addition to the validation of this technique, a set of default clinical test parameters was established. The VRT response morphology consisted of a biphasic waveform with an initial negative peak (N1) followed by a positive peak (P1), and latencies were typically 400 μs for N1 and 800 μs for P1. The consequences for the development of a vestibular implant for the improvement of gravitoinertial acceleration sensation are also presented. The VRT measurement technique has been shown to be a useful tool to record neural response on the otolith organ, and thus it is a convenient tool to evaluate whether the implanted electrodes provide a neural response or not. This can be used for the early development of vestibular implants to improve gravitoinertial acceleration sensation.

Role of cerebellar nodulus and uvula on the vestibular quick phase spatial constancy.

PubMed

Pettorossi, V E; Grassi, S; Errico, P; Barmack, N H

2001-01-01

We investigated the orientation of quick phases (QPs) of vestibularly-induced eye movements in rabbits in response to "off-vertical" sinusoidal vestibular stimulation. We also examined the possible role of the cerebellar nodulus and ventral uvula in controlling QP spatial orientation and modification. During "off-vertical" vestibular stimulation QPs remained aligned with the earth's horizontal plane, while the slow phases (SPs) were aligned with the plane of vestibular stimulation. This suggests that QPs are coded in gravito-inertial coordinates and SPs in head coordinates. When rabbits were oscillated in the light (20 degrees peak-to-peak; 0.2 Hz) about an "off-vertical" axis for 2 h, the QPs changed their trajectory, abandoning the earth's horizontal plane to approach the plane of the stimulus. By contrast, in the absence of conjunctive optokinetic stimulation, QPs remained fixed in the earth's horizontal plane even after 2 h of "off-vertical" stimulation. The conjunctive combination of optokinetic and vestibular stimulation caused QPs to change their plane of rotation. After lesion of the nodulus-uvula the ability of rabbits to reorient QPs during conjoint vestibular-optokinetic stimulation was maintained. We conclude that the space orientation and adaptation of QPs do not require cerebellar control.

Isolation and culture of adult mouse vestibular nucleus neurons

PubMed

Him, Aydın; Altuntaş, Serap; Öztürk, Gürkan; Erdoğan, Ender; Cengiz, Nureddin

2017-12-19

Background/aim: Isolated cell cultures are widely used to study neuronal properties due to their advantages. Although embryonic animals are preferred for culturing, their morphological or electrophysiological properties may not reflect adult neurons, which may be important in neurodegenerative diseases. This paper aims to develop a method for preparing isolated cell cultures of medial vestibular nucleus (MVN) from adult mice and describe its morphological and electrophysiological properties.Materials and methods: Vestibular nucleus neurons were mechanically and enzymatically isolated and cultured using a defined medium with known growth factors. Cell survival was measured with propidium iodide, and electrophysiological properties were investigated with current-clamp recording.Results: Vestibular neurons grew neurites in cultures, gaining adult-like morphological properties, and stayed viable for 3 days in culture. Adding bovine calf serum, nerve growth factor, or insulin-like growth factor into the culture medium enhanced neuronal viability. Current-clamp recording of the cultured neurons revealed tonic and phasic-type neurons with similar input resistance, resting membrane potential, action potential amplitude, and duration. Conclusion: Vestibular neurons from adult mice can be cultured, and regenerate axons in a medium containing appropriate growth factors. Culturing adult vestibular neurons provides a new method to study age-related pathologies of the vestibular system.

Patterning of sympathetic nerve activity in response to vestibular stimulation

NASA Technical Reports Server (NTRS)

Kerman, I. A.; McAllen, R. M.; Yates, B. J.

2000-01-01

Growing evidence suggests a role for the vestibular system in regulation of autonomic outflow during postural adjustments. In the present paper we review evidence for the patterning of sympathetic nerve activity elicited by vestibular stimulation. In response to electrical activation of vestibular afferents, firing of sympathetic nerves located throughout the body is altered. However, activity of the renal nerve is most sensitive to vestibular inputs. In contrast, high-intensity simultaneous activation of cutaneous and muscle inputs elicits equivalent changes in firing of the renal, superior mesenteric and lumbar colonic nerves. Responses of muscle vasoconstrictor (MVC) efferents to vestibular stimulation are either inhibitory (Type I) or are comprised of a combination of excitation and inhibition (Type II). Interestingly, single MVC units located in the hindlimb exhibited predominantly Type I responses while those located in the forelimb and face exhibited Type II responses. Furthermore, brachial and femoral arterial blood flows were dissociated in response to vestibular stimulation, such that brachial vascular resistance increased while femoral resistance decreased. These studies demonstrate that vestibulosympathetic reflexes are patterned according to both the anatomical location and innervation target of a particular sympathetic nerve, and can lead to distinct changes in local blood flow.

Utility of the hyperventilation test in the evaluation of the dizzy patient.

PubMed

Califano, Luigi; Mazzone, Salvatore; Salafia, Francesca

2013-10-01

The aim of the review is to value the incidence, patterns and temporal characteristics of hyperventilation-induced nystagmus (HVIN) in patients suffering from vestibular diseases, as well as its contribution to the differential diagnosis between vestibular neuritis and schwannoma of the eighth cranial nerve and its behavior in some central vestibular diseases. The hyperventilation test seems to be more useful than other bedside tests in detecting schwannoma of the eighth cranial nerve in the case of sudden monolateral hypacusia. The presence of an excitatory pattern of HVIN in vestibular schwannoma that has undergone to stereotactic surgery reveals that this therapy produces demyelinization in neural fibers. The hyperventilation test is easy to perform, well tolerated and able to reveal latent vestibular asymmetries; it acts both at peripheral and central vestibular levels through metabolic mechanisms or, more rarely, through changes in cerebrospinal fluid pressure. It can provide patterns of oculomotor responses suggesting the execution of gadolinium-enhanced MRI, upon the suspicion of schwannoma of the eighth cranial nerve or of a central disease. In our opinion, the presence of HVIN always needs to be viewed within the more general context of a complete examination of auditory and vestibular systems.

How imagery changes self-motion perception

PubMed Central

Nigmatullina, Y.; Arshad, Q.; Wu, K.; Seemungal, B.M.; Bronstein, A.M.; Soto, D.

2015-01-01

Imagery and perception are thought to be tightly linked, however, little is known about the interaction between imagery and the vestibular sense, in particular, self-motion perception. In this study, the observers were seated in the dark on a motorized chair that could rotate either to the right or to the left. Prior to the physical rotation, observers were asked to imagine themselves rotating leftward or rightward. We found that if the direction of imagined rotation was different to the physical rotation of the chair (incongruent trials), the velocity of the chair needed to be higher for observers to experience themselves rotating relative to when the imagined and the physical rotation matched (on congruent trials). Accordingly, the vividness of imagined rotations was reduced on incongruent relative to congruent trials. Notably, we found that similar effects of imagery were found at the earliest stages of vestibular processing, namely, the onset of the vestibular–ocular reflex was modulated by the congruency between physical and imagined rotations. Together, the results demonstrate that mental imagery influences self-motion perception by exerting top-down influences over the earliest vestibular response and subsequent perceptual decision-making. PMID:25637805

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

Human myosin VIIA responsible for the Usher 1B syndrome: a predicted membrane-associated motor protein expressed in developing sensory epithelia.

PubMed

Weil, D; Levy, G; Sahly, I; Levi-Acobas, F; Blanchard, S; El-Amraoui, A; Crozet, F; Philippe, H; Abitbol, M; Petit, C

1996-04-16

The gene encoding human myosin VIIA is responsible for Usher syndrome type III (USH1B), a disease which associates profound congenital sensorineural deafness, vestibular dysfunction, and retinitis pigmentosa. The reconstituted cDNA sequence presented here predicts a 2215 amino acid protein with a typical unconventional myosin structure. This protein is expected to dimerize into a two-headed molecule. The C terminus of its tail shares homology with the membrane-binding domain of the band 4.1 protein superfamily. The gene consists of 48 coding exons. It encodes several alternatively spliced forms. In situ hybridization analysis in human embryos demonstrates that the myosin VIIA gene is expressed in the pigment epithelium and the photoreceptor cells of the retina, thus indicating that both cell types may be involved in the USH1B retinal degenerative process. In addition, the gene is expressed in the human embryonic cochlear and vestibular neuroepithelia. We suggest that deafness and vestibular dysfunction in USH1B patients result from a defect in the morphogenesis of the inner ear sensory cell stereocilia.

Effects of sleep loss on vestibular response during simple and complex vestibular stimulation.

DOT National Transportation Integrated Search

1986-07-01

Few data are available concerning the effects of sleep loss on vestibular responses although those responses are significant products of motion in aviation environments. This study assessed periodically throughout approx. 55 hrs. of sleep loss the oc...

Adaptation to vestibular disorientation. VIII, "Coriolis" vestibular stimulation and the influence of different visual surrounds.

DOT National Transportation Integrated Search

1967-08-01

Disorientation caused by 'Coriolis' vestibular reactions has been cited frequently as a significant factor in flying safety. In addition, personnel who maintain rotating radar towers may also be adversely affected by 'Coriolis' problems. In the study...

Vestibular-induced vomiting after vestibulocerebellar lesions

NASA Technical Reports Server (NTRS)

Miller, A. D.; Wilson, V. J.

1983-01-01

Vestibular stimulation, by sinusoidal electrical polarization of the labyrinths of decerebrate cats which can produce vomiting and related activity which resembles motion sickness was examined. The symptoms include panting, salivation, swallowing, and retching as well as vomiting. These symptoms can be produced in cats with lesions of the posterior cerebellar vermis. It is suggested that a transcerebellar pathway from the vestibular apparatus through the nodulus and uvula to the vomiting center is not essential for vestibular induced vomiting and the occurrence of many symptoms of motion.

Vestibular-induced vomiting after vestibulocerebellar lesions

NASA Technical Reports Server (NTRS)

Miller, A. D.; Wilson, V. J.

1982-01-01

Vestibular stimulation, by sinusoidal electrical polarization of the labyrinths of decerebrate cats which can produce vomiting and related activity which resembles motion sickness was examined. The symptoms include panting, salivation, swallowing, and retching as well as vomiting. These symptoms can be produced in cats with lesions of the posterior cerebellar vermis. It is suggested that a transcerebellar pathway from the vestibular apparatus through the nodulus and uvula to the vomiting center is not essential for vestibular induced vomiting and the occurrence of many symptoms of motion.

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.

Muscarinic acetylcholine receptor subtype expression in avian vestibular hair cells, nerve terminals and ganglion cells.

PubMed

Li, G Q; Kevetter, G A; Leonard, R B; Prusak, D J; Wood, T G; Correia, M J

2007-04-25

Muscarinic acetylcholine receptors (mAChRs) are widely expressed in the CNS and peripheral nervous system and play an important role in modulating the cell activity and function. We have shown that the cholinergic agonist carbachol reduces the pigeon's inwardly rectifying potassium channel (pKir2.1) ionic currents in native vestibular hair cells. We have cloned and sequenced pigeon mAChR subtypes M2-M5 and we have studied the expression of all five mAChR subtypes (M1-M5) in the pigeon vestibular end organs (semicircular canal ampullary cristae and utricular maculae), vestibular nerve fibers and the vestibular (Scarpa's) ganglion using tissue immunohistochemistry (IH), dissociated single cell immunocytochemistry (IC) and Western blotting (WB). We found that vestibular hair cells, nerve fibers and ganglion cells each expressed all five (M1-M5) mAChR subtypes. Two of the three odd-numbered mAChRs (M1, M5) were present on the hair cell cilia, supporting cells and nerve terminals. And all three odd numbered mAChRs (M1, M3 and M5) were expressed on cuticular plates, myelin sheaths and Schwann cells. Even-numbered mAChRs were seen on the nerve terminals. M2 was also shown on the cuticular plates and supporting cells. Vestibular efferent fibers and terminals were not identified in our studies. Results from WB of the dissociated vestibular epithelia, nerve fibers and vestibular ganglia were consistent with the results from IH and IC. Our findings suggest that there is considerable co-expression of the subtypes on the neural elements of the labyrinth. Further electrophysiological and pharmacological studies should delineate the mechanisms of action of muscarinic acetylcholine receptors on structures in the labyrinth.

Analysis of vestibular testing in patients with vestibular schwannoma based on the nerve of origin, the localization, and the size of the tumor.

PubMed

Suzuki, Mitsuya; Yamada, Chikako; Inoue, Rika; Kashio, Akinori; Saito, Yuki; Nakanishi, Wakako

2008-10-01

We aimed to analyze the factors influencing caloric response and vestibular evoked myogenic potential (VEMP) in vestibular schwannoma. The subjects comprised 130 patients with unilateral vestibular schwannoma pathologically diagnosed by surgery. Caloric response and the amplitude and latency of VEMP were measured and analyzed based on the nerve of origin, localization, and size of the tumor. The tumors were classified into 3 types based on localization: intracanalicular, intermediate, and medial; and into 4 grades based on size: 9 mm or less, 10 to 19 mm, 20 to 29 mm, and 30 mm or greater. : Abnormal rates of caloric response and VEMP in patients with tumors arising from the superior vestibular nerve were not significantly different from those in patients with tumors of the inferior vestibular nerve. In the intermediate and medial type-but not in the intracanalicular type-a significant difference in tumor size was observed between patients with normal caloric response and those with canal paresis as also between patients with normal VEMP and those with abnormal VEMP. In patients with tumors that maximally measured 10 to 19 mm or of the intermediate type, the p- and n-wave latencies of VEMP were significantly prolonged compared with those in the normal opposite ear. 1) The nerve of origin of tumors cannot be predicted based on caloric response and VEMP. 2) In the intermediate and medial types, caloric response and the VEMP amplitude are significantly diminished in association with an increase in tumor size. 3) Prolonged VEMP latencies seem to be not only caused by tumor compression to the brainstem or vestibular spinal tract but also by tumor compression isolated to the inferior vestibular nerve.

Interactions of cervico-ocular and vestibulo-ocular fast-phase signals in the control of eye position in rabbits.

PubMed Central

Barmack, N H; Errico, P; Ferraresi, A; Pettorossi, V E

1989-01-01

1. Eye movements in unanaesthetized rabbits were studied during horizontal neck-proprioceptive stimulation (movement of the body with respect to the fixed head), when this stimulation was given alone and when it was given simultaneously with vestibular stimulation (rotation of the head-body). The effect of neck-proprioceptive stimulation on modifying the anticompensatory fast-phase eye movements (AFPs) evoked by vestibular stimulation was studied with a 'conditioning-test' protocol; the 'conditioning' stimulus was a neck-proprioceptive signal evoked by a step-like change in body position with respect to the head and the 'test' stimulus was a vestibular signal evoked by a step rotation of the head-body. 2. The influence of eye position and direction of slow eye movements on the occurrence of compensatory fast-phase eye movements (CFPs) evoked by neck-proprioceptive stimulation was also examined. 3. The anticompensatory fast phase (AFP) evoked by vestibular stimulation was attenuated by a preceding neck-proprioceptive stimulus which when delivered alone evoked compensatory slow-phase eye movements (CSP) in the same direction as the CSP evoked by vestibular stimulation. Conversely, the vestibularly evoked AFP was potentiated by a neck-proprioceptive stimulus which evoked CSPs opposite to that of vestibularly evoked CSPs. 4. Eccentric initial eye positions increased the probability of occurrence of midline-directed compensatory fast-phase eye movements (CFPs) evoked by appropriate neck-proprioceptive stimulation. 5. The gain of the horizontal cervico-ocular reflex (GHCOR) was measured from the combined changes in eye position resulting from AFPs and CSPs. GHCOR was potentiated during simultaneous vestibular stimulation. This enhancement of GHCOR occurred at neck-proprioceptive stimulus frequencies which, in the absence of conjoint vestibular stimulation, do not evoke CSPs. PMID:2795479

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

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.

Convergence of linear acceleration and yaw rotation signals on non-eye movement neurons in the vestibular nucleus of macaques.

PubMed

Newlands, Shawn D; Abbatematteo, Ben; Wei, Min; Carney, Laurel H; Luan, Hongge

2018-01-01

Roughly half of all vestibular nucleus neurons without eye movement sensitivity respond to both angular rotation and linear acceleration. Linear acceleration signals arise from otolith organs, and rotation signals arise from semicircular canals. In the vestibular nerve, these signals are carried by different afferents. Vestibular nucleus neurons represent the first point of convergence for these distinct sensory signals. This study systematically evaluated how rotational and translational signals interact in single neurons in the vestibular nuclei: multisensory integration at the first opportunity for convergence between these two independent vestibular sensory signals. Single-unit recordings were made from the vestibular nuclei of awake macaques during yaw rotation, translation in the horizontal plane, and combinations of rotation and translation at different frequencies. The overall response magnitude of the combined translation and rotation was generally less than the sum of the magnitudes in responses to the stimuli applied independently. However, we found that under conditions in which the peaks of the rotational and translational responses were coincident these signals were approximately additive. With presentation of rotation and translation at different frequencies, rotation was attenuated more than translation, regardless of which was at a higher frequency. These data suggest a nonlinear interaction between these two sensory modalities in the vestibular nuclei, in which coincident peak responses are proportionally stronger than other, off-peak interactions. These results are similar to those reported for other forms of multisensory integration, such as audio-visual integration in the superior colliculus. NEW & NOTEWORTHY This is the first study to systematically explore the interaction of rotational and translational signals in the vestibular nuclei through independent manipulation. The results of this study demonstrate nonlinear integration leading to maximum response amplitude when the timing and direction of peak rotational and translational responses are coincident.

An optimal control approach to the design of moving flight simulators

NASA Technical Reports Server (NTRS)

Sivan, R.; Ish-Shalom, J.; Huang, J.-K.

1982-01-01

An abstract flight simulator design problem is formulated in the form of an optimal control problem, which is solved for the linear-quadratic-Gaussian special case using a mathematical model of the vestibular organs. The optimization criterion used is the mean-square difference between the physiological outputs of the vestibular organs of the pilot in the aircraft and the pilot in the simulator. The dynamical equations are linearized, and the output signal is modeled as a random process with rational power spectral density. The method described yields the optimal structure of the simulator's motion generator, or 'washout filter'. A two-degree-of-freedom flight simulator design, including single output simulations, is presented.

Diagnosis of latent forms of labyrinthine affections

NASA Technical Reports Server (NTRS)

Vaslilyeva, V. P.

1980-01-01

Features and significance of individual vestibular symptoms for the diagnosis of latent labyrinthitis and limited forms of labyrinthine affections offering considerable difficulties are discussed. Vestibular symptoms are indistinct. In case of the negative fistular symptom the greatest significance is acquired by the study of posture nystagmus according to the results of electronystagmograms, changes of tonic reactions and statics, as well as data of experimental vestibular tests. The necessity of evaluation of all the vestibular symptoms from the point of view of their vector characteristics and in a complex of evidence obtained by otoneurological examination of the patient is emphasized. Delicate topic and differential diagnosis of vestibular disturbances is of great importance and significance in the choice of the conservative or surgical method of treatment.

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

Adaptation of postural recovery responses to a vestibular sensory illusion in individuals with Parkinson disease and healthy controls.

PubMed

Lester, Mark E; Cavanaugh, James T; Foreman, K Bo; Shaffer, Scott W; Marcus, Robin; Dibble, Leland E

2017-10-01

The ability to adapt postural responses to sensory illusions diminishes with age and is further impaired by Parkinson disease. However, limited information exists regarding training-related adaptions of sensory reweighting in these populations. This study sought to determine whether Parkinson disease or age would differentially affect acute postural recovery or adaptive postural responses to novel or repeated exposure to sensory illusions using galvanic vestibular stimulation during quiet stance. Acutely, individuals with Parkinson disease demonstrated larger center of pressure coefficient of variation compared to controls. Unlike individuals with Parkinson disease and asymptomatic older adults, healthy young adults acutely demonstrated a reduction in Sample Entropy to the sensory illusion. Following a period of consolidation Sample Entropy increased in the healthy young group, which coincided with a decreased center of pressure coefficient of variation. Similar changes were not observed in the Parkinson disease or older adult groups. Taken together, these results suggest that young adults learn to adapt to vestibular illusion in a more robust manner than older adults or those with Parkinson disease. Further investigation into the nature of this adaptive difference is warranted. Published by Elsevier Ltd.

Effect of meprobamate on the vestibulosensory and vestibular somatic reaction

NASA Technical Reports Server (NTRS)

Khinchikashvili, N. V.

1980-01-01

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

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.

An experimental vestibular neural prosthesis: design and preliminary results with rhesus monkeys stimulated with modulated pulses.

PubMed

Nie, Kaibao; Ling, Leo; Bierer, Steven M; Kaneko, Chris R S; Fuchs, Albert F; Oxford, Trey; Rubinstein, Jay T; Phillips, James O

2013-06-01

A vestibular neural prosthesis was designed on the basis of a cochlear implant for treatment of Meniere's disease and other vestibular disorders. Computer control software was developed to generate patterned pulse stimuli for exploring optimal parameters to activate the vestibular nerve. Two rhesus monkeys were implanted with the prototype vestibular prosthesis and they were behaviorally evaluated post implantation surgery. Horizontal and vertical eye movement responses to patterned electrical pulse stimulations were collected on both monkeys. Pulse amplitude modulated (PAM) and pulse rate modulated (PRM) trains were applied to the lateral canal of each implanted animal. Robust slow-phase nystagmus responses following the PAM or PRM modulation pattern were observed in both implanted monkeys in the direction consistent with the activation of the implanted canal. Both PAM and PRM pulse trains can elicit a significant amount of in-phase modulated eye velocity changes and they could potentially be used for efficiently coding head rotational signals in future vestibular neural prostheses.

PubMed Central

CALIFANO, L.; MELILLO, M.G.; VASSALLO, A.; MAZZONE, S.

2011-01-01

SUMMARY The Hyperventilation Test is widely used in the "bed-side examination" of vestibular patients. It can either activate a latent nystagmus in central or peripheral vestibular diseases or it can interact with a spontaneous nystagmus, by reducing it or increasing it. Aims of this study were to determine the incidence, patterns and temporal characteristics of Hyperventilation-induced nystagmus in patients suffering from vestibular diseases, as well as its contribution to the differential diagnosis between vestibular neuritis and neuroma of the 8th cranial nerve, and its behaviour in some central vestibular diseases. The present study includes 1202 patients featuring, at vestibular examination, at least one sign of vestibular system disorders or patients diagnosed with a "Migraine-related vertigo" or "Chronic subjective dizziness". The overall incidence of Hyperventilation-induced nystagmus was 21.9%. It was detected more frequently in retrocochlear vestibular diseases rather than in end-organ vestibular diseases: 5.3% in Paroxysmal Positional Vertigo, 37.1% in Menière's disease, 37.6% in compensated vestibular neuritis, 77.2% in acute vestibular neuritis and 91.7% in neuroma of the 8th cranial nerve. In acute vestibular neuritis, three HVIN patterns were observed: Paretic pattern: temporary enhancement of the spontaneous nystagmus; Excitatory pattern: temporary inhibition of the spontaneous nystagmus; Strong excitatory pattern: temporary inversion of the spontaneous nystagmus. Excitatory patterns proved to be time-dependent in that they disappeared and were replaced by the paretic pattern over a period of maximum 18 days since the beginning of the disorder. In acoustic neuroma, Hyperventilation-induced nystagmus was frequently observed (91.7%), either in the form of an excitatory pattern (fast phases towards the affected site) or in the form of a paretic pattern (fast phases towards the healthy side). The direction of the nystagmus is only partially related to tumour size, whereas other mechanisms, such as demyelination or a break in nerve fibres, might have an important role in triggering the situation. Hyperventilation-induced nystagmus has frequently been detected in cases of demyelinating diseases and in cerebellar diseases: in multiple sclerosis, hyperventilation inhibits a central type of spontaneous nystagmus or evokes nystagmus in 75% of patients; in cerebellar diseases, hyperventilation evokes or enhances a central spontaneous nystagmus in 72.7% of patients. In conclusion the Hyperventilation Test can provide patterns of oculomotor responses that indicate a diagnostic investigation through cerebral magnetic resonance imaging enhanced by gadolinium, upon suspicion of neuroma of the 8th cranial nerve or of a central disease. In our opinion, however, Hyperventilation-induced nystagmus always needs to be viewed within the more general context of a complete examination of the vestibular and acoustic system. PMID:21808459

A quantitative analysis of gait patterns in vestibular neuritis patients using gyroscope sensor and a continuous walking protocol

PubMed Central

2014-01-01

Background Locomotion involves an integration of vision, proprioception, and vestibular information. The parieto-insular vestibular cortex is known to affect the supra-spinal rhythm generators, and the vestibular system regulates anti-gravity muscle tone of the lower leg in the same side to maintain an upright posture through the extra-pyramidal track. To demonstrate the relationship between locomotion and vestibular function, we evaluated the differences in gait patterns between vestibular neuritis (VN) patients and normal subjects using a gyroscope sensor and long-way walking protocol. Methods Gyroscope sensors were attached to both shanks of healthy controls (n=10) and age-matched VN patients (n = 10). We then asked the participants to walk 88.8 m along a corridor. Through the summation of gait cycle data, we measured gait frequency (Hz), normalized angular velocity (NAV) of each axis for legs, maximum and minimum NAV, up-slope and down-slope of NAV in swing phase, stride-swing-stance time (s), and stance to stride ratio (%). Results The most dominant walking frequency in the VN group was not different compared to normal control. The NAVs of z-axis (pitch motion) were significantly larger than the others (x-, y-axis) and the values in VN patients tended to decrease in both legs and the difference of NAV between both group was significant in the ipsi-lesion side in the VN group only (p=0.03). Additionally, the gait velocity of these individuals was decreased relatively to controls (1.11 ± 0.120 and 0.84 ± 0.061 m/s in control and VN group respectively, p<0.01), which seems to be related to the significantly increased stance and stride time of the ipsi-lesion side. Moreover, in the VN group, the maximum NAV of the lesion side was less, and the minimum one was higher than control group. Furthermore, the down-slope and up-slope of NAV decreased on the impaired side. Conclusion The walking pattern of VN patients was highly phase-dependent, and NAV of pitch motion was significantly decreased in the ipsi-lesion side. The change of gait rhythm, stance and stride time, and maximum/minimum NAV of the ipsi-lesion side were characteristics of individuals with VN. PMID:24725764

A quantitative analysis of gait patterns in vestibular neuritis patients using gyroscope sensor and a continuous walking protocol.

PubMed

Kim, Soo Chan; Kim, Joo Yeon; Lee, Hwan Nyeong; Lee, Hwan Ho; Kwon, Jae Hwan; Kim, Nam Beom; Kim, Mi Joo; Hwang, Jong Hyun; Han, Gyu Cheol

2014-04-11

Locomotion involves an integration of vision, proprioception, and vestibular information. The parieto-insular vestibular cortex is known to affect the supra-spinal rhythm generators, and the vestibular system regulates anti-gravity muscle tone of the lower leg in the same side to maintain an upright posture through the extra-pyramidal track. To demonstrate the relationship between locomotion and vestibular function, we evaluated the differences in gait patterns between vestibular neuritis (VN) patients and normal subjects using a gyroscope sensor and long-way walking protocol. Gyroscope sensors were attached to both shanks of healthy controls (n=10) and age-matched VN patients (n = 10). We then asked the participants to walk 88.8 m along a corridor. Through the summation of gait cycle data, we measured gait frequency (Hz), normalized angular velocity (NAV) of each axis for legs, maximum and minimum NAV, up-slope and down-slope of NAV in swing phase, stride-swing-stance time (s), and stance to stride ratio (%). The most dominant walking frequency in the VN group was not different compared to normal control. The NAVs of z-axis (pitch motion) were significantly larger than the others (x-, y-axis) and the values in VN patients tended to decrease in both legs and the difference of NAV between both group was significant in the ipsi-lesion side in the VN group only (p=0.03). Additionally, the gait velocity of these individuals was decreased relatively to controls (1.11 ± 0.120 and 0.84 ± 0.061 m/s in control and VN group respectively, p<0.01), which seems to be related to the significantly increased stance and stride time of the ipsi-lesion side. Moreover, in the VN group, the maximum NAV of the lesion side was less, and the minimum one was higher than control group. Furthermore, the down-slope and up-slope of NAV decreased on the impaired side. The walking pattern of VN patients was highly phase-dependent, and NAV of pitch motion was significantly decreased in the ipsi-lesion side. The change of gait rhythm, stance and stride time, and maximum/minimum NAV of the ipsi-lesion side were characteristics of individuals with VN.

Convergent properties of vestibular-related brain stem neurons in the gerbil

NASA Technical Reports Server (NTRS)

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

2000-01-01

Three classes of vestibular-related neurons were found in and near the prepositus and medial vestibular nuclei of alert or decerebrate gerbils, those responding to: horizontal translational motion, horizontal head rotation, or both. Their distribution ratios were 1:2:2, respectively. Many cells responsive to translational motion exhibited spatiotemporal characteristics with both response gain and phase varying as a function of the stimulus vector angle. Rotationally sensitive neurons were distributed as Type I, II, or III responses (sensitive to ipsilateral, contralateral, or both directions, respectively) in the ratios of 4:6:1. Four tested factors shaped the response dynamics of the sampled neurons: canal-otolith convergence, oculomotor-related activity, rotational Type (I or II), and the phase of the maximum response. Type I nonconvergent cells displayed increasing gains with increasing rotational stimulus frequency (0.1-2.0 Hz, 60 degrees /s), whereas Type II neurons with convergent inputs had response gains that markedly decreased with increasing translational stimulus frequency (0.25-2.0 Hz, +/-0.1 g). Type I convergent and Type II nonconvergent neurons exhibited essentially flat gains across the stimulus frequency range. Oculomotor-related activity was noted in 30% of the cells across all functional types, appearing as burst/pause discharge patterns related to the fast phase of nystagmus during head rotation. Oculomotor-related activity was correlated with enhanced dynamic range compared with the same category that had no oculomotor-related response. Finally, responses that were in-phase with head velocity during rotation exhibited greater gains with stimulus frequency increments than neurons with out-of-phase responses. In contrast, for translational motion, neurons out of phase with head acceleration exhibited low-pass characteristics, whereas in-phase neurons did not. Data from decerebrate preparations revealed that although similar response types could be detected, the sampled cells generally had lower background discharge rates, on average one-third lower response gains, and convergent properties that differed from those found in the alert animals. On the basis of the dynamic response of identified cell types, we propose a pair of models in which inhibitory input from vestibular-related neurons converges on oculomotor neurons with excitatory inputs from the vestibular nuclei. Simple signal convergence and combinations of different types of vestibular labyrinth information can enrich the dynamic characteristics of the rotational and translational vestibuloocular responses.

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.

Brain or strain? Symptoms alone do not distinguish physiologic concussion from cervical/vestibular injury.

PubMed

Leddy, John J; Baker, John G; Merchant, Asim; Picano, John; Gaile, Daniel; Matuszak, Jason; Willer, Barry

2015-05-01

To compare symptoms in patients with physiologic postconcussion disorder (PCD) versus cervicogenic/vestibular PCD. We hypothesized that most symptoms would not be equivalent. In particular, we hypothesized that cognitive symptoms would be more often associated with physiologic PCD. Retrospective review of symptom reports from patients who completed a 22-item symptom questionnaire. University-based concussion clinic. Convenience sample of 128 patients who had symptoms after head injury for more than 3 weeks and who had provocative treadmill exercise testing. Subjects were classified as either physiologic PCD (abnormal treadmill performance and a normal cervical/vestibular physical examination) or cervicogenic/vestibular PCD (CGV, normal treadmill performance, and an abnormal cervical/vestibular physical examination). Self-reported symptoms. Univariate and multivariate methods, including t tests, tests of equivalence, a logistic regression model, k-nearest neighbor analysis, multidimensional scaling, and principle components analysis were used to see whether symptoms could distinguish PCD from CGV. None of the statistical methods used to analyze self-reported symptoms was able to adequately distinguish patients with PCD from patients with CGV. Symptoms after head injury, including cognitive symptoms, have traditionally been ascribed to brain injury, but they do not reliably discriminate between physiologic PCD and cervicogenic/vestibular PCD. Clinicians should consider specific testing of exercise tolerance and perform a physical examination of the cervical spine and the vestibular/ocular systems to determine the etiology of postconcussion symptoms. Symptoms after head injury, including cognitive symptoms, do not discriminate between concussion and cervical/vestibular injury.

Adaptive plasticity in vestibular influences on cardiovascular control

NASA Technical Reports Server (NTRS)

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

2000-01-01

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

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.

Assessment of Vestibular Rehabilitation Therapy Training and Practice Patterns

PubMed Central

Bush, Matthew L.; Dougherty, William

2015-01-01

Objective Vestibular rehabilitation therapy (VRT) can benefit patients with a variety of balance and vestibular disorders. This expanding field requires knowledgeable and experienced therapists; however, the practice and experience of those providing this care may vary greatly. The purpose of this study was to analyze variations in training and practice patterns among practicing vestibular rehabilitation therapists. Study Design Case-controlled cohort study Setting Investigation of outpatient physical therapy and audiology practices that offer vestibular rehabilitation conducted by a tertiary academic referral center. Main Outcome Measure Questionnaire-based investigation of level of training in vestibular disorders and therapy, practice patterns of vestibular rehabilitation, and referral sources for VRT patients. Results We identified 27 subjects within the state of Kentucky who practice vestibular rehabilitation and the questionnaire response rate was 63%. Responses indicated that 53% of respondents had no training in VRT during their professional degree program. Attendance of a course requiring demonstration of competence and techniques was 24% of participants. The development of VRT certification was significantly more favored by those who attended such courses compared with those who did not (p=0.01). 50% of therapists have direct access to patients without physician referrals. Conclusions There is a wide range of educational background and training among those practicing VRT. This variability in experience may affect care provided within some communities. Certification is not necessary for the practice of VRT but the development of certification is favored among some therapists to improve standardization of practice of this important specialty. PMID:25700790

Assessment of Vestibular Rehabilitation Therapy Training and Practice Patterns.

PubMed

Bush, Matthew L; Dougherty, William

2015-08-01

Vestibular rehabilitation therapy (VRT) can benefit patients with a variety of balance and vestibular disorders. This expanding field requires knowledgeable and experienced therapists; however, the practice and experience of those providing this care may vary greatly. The purpose of this study was to analyze variations in training and practice patterns among practicing vestibular rehabilitation therapists. Case-controlled cohort study. Investigation of outpatient physical therapy and audiology practices that offer vestibular rehabilitation conducted by a tertiary academic referral center. Questionnaire-based investigation of level of training in vestibular disorders and therapy, practice patterns of vestibular rehabilitation, and referral sources for VRT patients. We identified 27 subjects within the state of Kentucky who practice vestibular rehabilitation and the questionnaire response rate was 63%. Responses indicated that 53% of respondents had no training in VRT during their professional degree program. Attendance of a course requiring demonstration of competence and techniques was 24% of participants. The development of VRT certification was significantly more favored by those who attended such courses compared with those who did not (p = 0.01). 50% of therapists have direct access to patients without physician referrals. There is a wide range of educational background and training among those practicing VRT. This variability in experience may affect care provided within some communities. Certification is not necessary for the practice of VRT but the development of certification is favored among some therapists to improve standardization of practice of this important specialty.

Symptoms and signs of neuro-otologic disorders.

PubMed

Newman-Toker, David E

2012-10-01

Symptoms and signs of neuro-otologic disorders are critical components in the diagnostic assessment of patients with vestibular symptoms such as vertigo, dizziness, unsteadiness, and oscillopsia. Most diagnoses can be accomplished at the bedside. An understanding of key diagnostic principles is essential for all practicing neurologists, who are often faced with determining whether such patients warrant urgent diagnostic testing or hospital admission. This article introduces readers to core concepts and recent advances in the understanding of directed history taking and physical examination in patients with vestibular symptoms or suspected neuro-otologic disorders. International consensus definitions for vestibular symptoms have recently been published. During the past 5 years, a growing body of scientific evidence has demonstrated that the traditional approach to bedside diagnosis of patients with vertigo and dizziness is inadequate. Former teaching that history taking should first rely on categorizing symptoms by type (eg, vertigo, presyncope, disequilibrium, nonspecific dizziness) has been replaced by an emphasis on categorizing timing and triggers for vestibular symptoms, which focuses the clinician's attention on four key syndromic patterns: (1) acute, spontaneous, prolonged vestibular symptoms; (2) episodic, positional vestibular symptoms; (3) episodic, spontaneous vestibular symptoms; and (4) chronic unsteadiness (with or without oscillopsia). Each of these categories delineates a relatively narrow differential diagnosis within which a focused examination distinguishes between benign common causes and dangerous uncommon ones. A focused approach to bedside assessment of patients with vestibular symptoms is essential for accurate and efficient diagnosis. All neurologists should be aware of major recent advances.