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Sample records for vestibular stochastic resonance

  1. 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

  2. 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.

  3. 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

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    Astronauts experience disturbances in sensorimotor function after spaceflight during the initial introduction to a gravitational environment, especially after long-duration missions. Stochastic resonance (SR) is a mechanism by which noise can assist and enhance the response of neural systems to relevant, imperceptible sensory signals. We have previously shown that imperceptible electrical stimulation of the vestibular system enhances balance performance while standing on an unstable surface. The goal of our present study is to develop a countermeasure based on vestibular SR that could improve central interpretation of vestibular input and improve motor task responses to mitigate associated risks.

  5. Optimization of Stimulus Characteristics for Vestibular Stochastic Resonance to Improve Balance Function

    NASA Technical Reports Server (NTRS)

    Mulavara, Ajitkumar; Fiedler, Matthew; Kofman, Igor; Acock, Keena; DeDios, Yiri E.; Heap, Erin; Peters, Brian; Wood, Scott; Serrador, Jorge; Cohen, Helen; Reschke, Millard; Bloomberg, Jacob

    2010-01-01

    Stochastic resonance (SR) is a mechanism by which noise can assist and enhance the response of neural systems to relevant sensory signals. Recent studies have shown that applying imperceptible stochastic noise electrical stimulation to the vestibular system significantly improved balance and ocular motor responses. The goal of this study was to optimize the amplitude of the stochastic vestibular signals for balance performance during standing on an unstable surface. Subjects performed a standardized balance task of standing on a block of 10-cm-thick medium-density foam with their eyes closed. Balance performance was measured using a force plate under the foam block and using inertial motion sensors placed on the torso and head segments. Stochastic electrical stimulation was applied to the vestibular system through electrodes placed over the mastoid process. Subjects were tested at seven amplitudes in the 0.01-30Hz frequency range. The root mean square of the signal increased by 30 microamperes for each +/-100 microampere increment in the current range of 0 - +/-700 microampere. Six balance parameters were calculated to characterize the performance of subjects during the baseline and the stimulus periods for all seven amplitudes. Optimal stimulus amplitude was determined as the one at which the ratio of parameters from the stimulus period to the baseline period for any amplitude range was less than that for the no stimulus condition on a minimum of four of six parameters. Results from this study showed that balance performance at the optimal stimulus amplitude showed significant improvement with the application of the vestibular SR stimulation. The amplitude of optimal stimulus for improving balance performance in normal subjects was in the range of +/-100 - +/-300 microamps.

  6. Vestibular Stochastic Resonance as a Method to Improve Balance Function: Optimization of Stimulus Characteristics

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    Stochastic resonance (SR) is a mechanism by which noise can assist and enhance the response of neural systems to relevant sensory signals. Application of imperceptible SR noise coupled with sensory input through the proprioceptive, visual, or vestibular sensory systems has been shown to improve motor function. Specifically, studies have shown that that vestibular electrical stimulation by imperceptible stochastic noise, when applied to normal young and elderly subjects, significantly improved their ocular stabilization reflexes in response to whole-body tilt as well as balance performance during postural disturbances. The goal of this study was to optimize the characteristics of the stochastic vestibular signals for balance performance during standing on an unstable surface. Subjects performed a standardized balance task of standing on a block of 10 cm thick medium density foam with their eyes closed for a total of 40 seconds. Stochastic electrical stimulation was applied to the vestibular system through electrodes placed over the mastoid process behind the ears during the last 20 seconds of the test period. A custom built constant current stimulator with subject isolation delivered the stimulus. Stimulation signals were generated with frequencies in the bandwidth of 1-2 Hz and 0.01-30 Hz. Amplitude of the signals were varied in the range of 0- +/-700 micro amperes with the RMS of the signal increased by 30 micro amperes for each 100 micro amperes increase in the current range. Balance performance was measured using a force plate under the foam block and inertial motion sensors placed on the torso and head segments. Preliminary results indicate that balance performance is improved in the range of 10-25% compared to no stimulation conditions. Subjects improved their performance consistently across the blocks of stimulation. Further the signal amplitude at which the performance was maximized was different in the two frequency ranges. Optimization of the frequency and

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

    PubMed

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

    2016-05-13

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

  8. Functional stochastic resonance in human baroreflex induced by 1/f-type noisy galvanic vestibular stimulation

    NASA Astrophysics Data System (ADS)

    Soma, Rika; Kwak, Shin; Yamamoto, Yoshiharu

    2003-05-01

    We hypothesized that 1/f noise is more beneficial than the conventional white noise in optimizing the brain's response to a weak input signal, and showed that externally added 1/f noise outperforms white noise in sensitizing human baroreflex centers in the brain. We examined the compensatory heart rate response to weak periodic signal introduced at the venous blood pressure receptor, while adding either 1/f or white noise with the same variance to the brain stem by electrically stimulating the bilateral vestibular afferents cutaneously. This stochastic galvanic vestibular stimulation, activating the vestibulo-sympathetic pathway in the brain stem, optimized covariance between weak input signals and the heart rate responses both with 1/f and white noise. Further, the optimal noise level with 1/f noise was significantly lower than that with white noise, suggesting the functional benefit of 1/f noise for the neuronal information transfer in the brain.

  9. 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.; Wood, S.; Bloomberg, J. J.; Mulavara, A. P.

    2015-01-01

    Sensorimotor changes such as postural and gait instabilities can affect the functional performance of astronauts when they transition across different gravity environments. We are developing a method, based on stochastic resonance (SR), to enhance information transfer by applying non-zero levels of external noise on the vestibular system (vestibular stochastic resonance, VSR). The goal of this project was to determine optimal levels of stimulation for SR applications by using a defined vestibular threshold of motion detection.

  10. Improving Sensorimotor Function Using Stochastic Vestibular Stimulation

    NASA Technical Reports Server (NTRS)

    Galvan, R. C.; Clark, T. K.; Merfeld, D. M.; Bloomberg, J. J.; Mulavara, A. P.; Oman, C. M.

    2014-01-01

    Astronauts experience sensorimotor changes during spaceflight, particularly during G-transition phases. Post flight sensorimotor changes may include postural and gait instability, spatial disorientation, and visual performance decrements, all of which can degrade operational capabilities of the astronauts and endanger the crew. Crewmember safety would be improved if these detrimental effects of spaceflight could be mitigated by a sensorimotor countermeasure and even further if adaptation to baseline could be facilitated. 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 performance through stochastic resonance (SR). The SR phenomenon occurs when the response of a nonlinear system to a weak input signal is optimized by the application of a particular nonzero level of noise. Two studies have been initiated to investigate the beneficial effects and potential practical usage of SVS. In both studies, electrical vestibular stimulation is applied via electrodes on the mastoid processes using a constant current stimulator. The first study aims to determine the repeatability of the effect of vestibular stimulation on sensorimotor performance and perception in order to better understand the practical use of SVS. The beneficial effect of low levels of SVS on balance performance has been shown in the past. This research uses the same balance task repeated multiple times within a day and across days to study the repeatability of the stimulation effects. The balance test consists of 50 sec trials in which the subject stands with his or her feet together, arms crossed, and eyes closed on compliant foam. Varying levels of SVS, ranging from 0-700 micro A, are applied across different trials. The subject-specific optimal SVS level is that which results in the best balance performance as measured by inertial

  11. Efficacy of Stochastic Vestibular Stimulation to Improve Locomotor Performance in a Discordant Sensory Environment

    NASA Technical Reports Server (NTRS)

    Temple, D. R.; De Dios, Y. E.; Layne, C. S.; Bloomberg, J. J.; Mulavara, A. P.

    2016-01-01

    Astronauts exposed to microgravity face sensorimotor challenges incurred when readapting to a gravitational environment. Sensorimotor Adaptability (SA) training has been proposed as a countermeasure to improve locomotor performance during re-adaptation, and it is suggested that the benefits of SA training may be further enhanced by improving detection of weak sensory signals via mechanisms such as stochastic resonance when a non-zero level of stochastic white noise based electrical stimulation is applied to the vestibular system (stochastic vestibular stimulation, SVS). The purpose of this study was to test the efficacy of using SVS to improve short-term adaptation in a sensory discordant environment during performance of a locomotor task.

  12. Improving Sensorimotor Function and Adaptation using Stochastic Vestibular Stimulation

    NASA Technical Reports Server (NTRS)

    Galvan, R. C.; Bloomberg, J. J.; Mulavara, A. P.; Clark, T. K.; Merfeld, D. M.; Oman, C. M.

    2014-01-01

    Astronauts experience sensorimotor changes during adaption to G-transitions that occur when entering and exiting microgravity. Post space flight, these sensorimotor disturbances can include postural and gait instability, visual performance changes, manual control disruptions, spatial disorientation, and motion sickness, all of which can hinder the operational capabilities of the astronauts. Crewmember safety would be significantly increased if sensorimotor changes brought on by gravitational changes could be mitigated and adaptation could be facilitated. The goal of this research is to investigate and develop the use of electrical stochastic vestibular stimulation (SVS) as a countermeasure to augment sensorimotor function and facilitate adaptation. For this project, SVS will be applied via electrodes on the mastoid processes at imperceptible amplitude levels. We hypothesize that SVS will improve sensorimotor performance through the phenomena of stochastic resonance, which occurs when the response of a nonlinear system to a weak input signal is optimized by the application of a particular nonzero level of noise. In line with the theory of stochastic resonance, a specific optimal level of SVS will be found and tested for each subject [1]. Three experiments are planned to investigate the use of SVS in sensory-dependent tasks and performance. The first experiment will aim to demonstrate stochastic resonance in the vestibular system through perception based motion recognition thresholds obtained using a 6-degree of freedom Stewart platform in the Jenks Vestibular Laboratory at Massachusetts Eye and Ear Infirmary. A range of SVS amplitudes will be applied to each subject and the subjectspecific optimal SVS level will be identified as that which results in the lowest motion recognition threshold, through previously established, well developed methods [2,3,4]. The second experiment will investigate the use of optimal SVS in facilitating sensorimotor adaptation to system

  13. 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.; Mulavara, A.P.

    2015-01-01

    Sensorimotor changes such as postural and gait instabilities can affect the functional performance of astronauts when they transition across different gravity environments. We are developing a method, based on stochastic resonance (SR), to enhance information transfer by applying non-zero levels of external noise on the vestibular system (vestibular stochastic resonance, VSR). Our previous work has shown the advantageous effects of VSR in a balance task of standing on an unstable surface [1]. This technique to improve detection of vestibular signals uses a stimulus delivery system that provides imperceptibly low levels of white noise-based binaural bipolar electrical stimulation of the vestibular system. The goal of this project is to determine optimal levels of stimulation for SR applications by using a defined vestibular threshold of motion detection. A series of experiments were carried out to determine a robust paradigm to identify a vestibular threshold that can then be used to recommend optimal stimulation levels for sensorimotor adaptability (SA) training applications customized to each crewmember. The amplitude of stimulation to be used in the VSR application has varied across studies in the literature such as 60% of nociceptive stimulus thresholds [2]. We compared subjects' perceptual threshold with that obtained from two measures of body sway. Each test session was 463s long and consisted of several 15s long sinusoidal stimuli, at different current amplitudes (0-2 mA), interspersed with 20-20.5s periods of no stimulation. Subjects sat on a chair with their eyes closed and had to report their perception of motion through a joystick. A force plate underneath the chair recorded medio-lateral shear forces and roll moments. Comparison of threshold of motion detection obtained from joystick data versus body sway suggests that perceptual thresholds were significantly lower. In the balance task, subjects stood on an unstable surface and had to maintain balance

  14. 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.; Mulavara, A. P.

    2014-01-01

    Sensorimotor changes such as postural and gait instabilities can affect the functional performance of astronauts when they transition across different gravity environments. We are developing a method, based on stochastic resonance (SR), to enhance information transfer by applying non-zero levels of external noise on the vestibular system (vestibular stochastic resonance, VSR). Our previous work has shown the advantageous effects of VSR in a balance task of standing on an unstable surface. This technique to improve detection of vestibular signals uses a stimulus delivery system that is wearable or portable and provides imperceptibly low levels of white noise-based binaural bipolar electrical stimulation of the vestibular system. The goal of this project is to determine optimal levels of stimulation for SR applications by using a defined vestibular threshold of motion detection. A series of experiments were carried out to determine a robust paradigm to identify a vestibular threshold that can then be used to recommend optimal stimulation levels for SR training applications customized to each crewmember. Customizing stimulus intensity can maximize treatment effects. The amplitude of stimulation to be used in the VSR application has varied across studies in the literature such as 60% of nociceptive stimulus thresholds. We compared subjects' perceptual threshold with that obtained from two measures of body sway. Each test session was 463s long and consisted of several 15s sinusoidal stimuli, at different current amplitudes (0-2 mA), interspersed with 20-20.5s periods of no stimulation. Subjects sat on a chair with their eyes closed and had to report their perception of motion through a joystick. A force plate underneath the chair recorded medio-lateral shear forces and roll moments. First we determined the percent time during stimulation periods for which perception of motion (activity above a pre-defined threshold) was reported using the joystick, and body sway (two

  15. Using low levels of stochastic vestibular stimulation to improve locomotor stability

    PubMed Central

    Mulavara, Ajitkumar P.; Kofman, Igor S.; De Dios, Yiri E.; Miller, Chris; Peters, Brian T.; Goel, Rahul; Galvan-Garza, Raquel; Bloomberg, Jacob J.

    2015-01-01

    Low levels of bipolar binaural white noise based imperceptible stochastic electrical stimulation to the vestibular system (stochastic vestibular stimulation, SVS) have been shown to improve stability during balance tasks in normal, healthy subjects by facilitating enhanced information transfer using stochastic resonance (SR) principles. We hypothesize that detection of time-critical sub-threshold sensory signals using low levels of bipolar binaural SVS based on SR principles will help improve stability of walking during support surface perturbations. In the current study 13 healthy subjects were exposed to short continuous support surface perturbations for 60 s while walking on a treadmill and simultaneously viewing perceptually matched linear optic flow. Low levels of bipolar binaural white noise based SVS were applied to the vestibular organs. Multiple trials of the treadmill locomotion test were performed with stimulation current levels varying in the range of 0–1500 μA, randomized across trials. The results show that subjects significantly improved their walking stability during support surface perturbations at stimulation levels with peak amplitude predominantly in the range of 100–500 μA consistent with the SR phenomenon. Additionally, objective perceptual motion thresholds were measured separately as estimates of internal noise while subjects sat on a chair with their eyes closed and received 1 Hz bipolar binaural sinusoidal electrical stimuli. The optimal improvement in walking stability was achieved on average with peak stimulation amplitudes of approximately 35% of perceptual motion threshold. This study shows the effectiveness of using low imperceptible levels of SVS to improve dynamic stability during walking on a laterally oscillating treadmill via the SR phenomenon. PMID:26347619

  16. Stochastic resonance in nanomechanical systems

    NASA Astrophysics Data System (ADS)

    Badzey, Robert L.

    The phenomenon of stochastic resonance is a counter-intuitive one: adding noise to a noisy nonlinear system under the influence of a modulation results in coherent behavior. The signature of the effect is a resonance in the signal-to-noise ratio of the response over a certain range of noise power; this behavior is absent if either the modulation or the noise are absent. Stochastic resonance has attracted considerable interest over the past several decades, having been seen in a great number of physical and biological systems. Here, observation of stochastic resonance is reported for nanomechanical systems consisting of a doubly-clamped beam resonators fabricated from single-crystal silicon. Such oscillators have been found to display nonlinear and bistable behavior under the influence of large driving forces. This bistability is exploited to produce a controllable nanomechanical switch, a device that may be used as the basis for a new generation of computational memory elements. These oscillators possess large intrinsic resonance frequencies (MHz range or higher) due to their small size and relatively high stiffness; thus they have the potential to rival the current state-of-the-art of electronic and magnetic storage technologies. This small size also allows them to be packed in densities which meet or exceed the superparamagnetic limit for magnetic storage media of 100 GB/in2. Two different doubly-clamped beams were cooled to low temperatures (300 mK--4 K), and excited with a magnetomotive technique. They were driven into the nonlinear response regime, and then modulated to induce switching between their bistable states. When the modulation was reduced, the switching died out. Application of noise, either with an external broadband source or via an increase in temperature, resulted in a distinct resonance in the signal-to-noise ratio. Aside from establishing the phenomenon of stochastic resonance in yet another physical system, the observation of this effect has

  17. Stochastic resonance on a circle

    SciTech Connect

    Wiesenfeld, K. ); Pierson, D.; Pantazelou, E.; Dames, C.; Moss, F. )

    1994-04-04

    We describe a new realization of stochastic resonance, applicable to a broad class of systems, based on an underlying excitable dynamics with deterministic reinjection. A simple but general theory of such single-trigger'' systems is compared with analog simulations of the Fitzhugh-Nagumo model, as well as experimental data obtained from stimulated sensory neurons in the crayfish.

  18. Brownian motors and stochastic resonance.

    PubMed

    Mateos, José L; Alatriste, Fernando R

    2011-12-01

    We study the transport properties for a walker on a ratchet potential. The walker consists of two particles coupled by a bistable potential that allow the interchange of the order of the particles while moving through a one-dimensional asymmetric periodic ratchet potential. We consider the stochastic dynamics of the walker on a ratchet with an external periodic forcing, in the overdamped case. The coupling of the two particles corresponds to a single effective particle, describing the internal degree of freedom, in a bistable potential. This double-well potential is subjected to both a periodic forcing and noise and therefore is able to provide a realization of the phenomenon of stochastic resonance. The main result is that there is an optimal amount of noise where the amplitude of the periodic response of the system is maximum, a signal of stochastic resonance, and that precisely for this optimal noise, the average velocity of the walker is maximal, implying a strong link between stochastic resonance and the ratchet effect.

  19. Stochastic resonance across bifurcation cascades

    NASA Astrophysics Data System (ADS)

    Nicolis, C.; Nicolis, G.

    2017-03-01

    The classical setting of stochastic resonance is extended to account for parameter variations leading to transitions between a unique stable state, bistability, and multistability regimes, across singularities of various kinds. Analytic expressions for the amplitude and the phase of the response in terms of key parameters are obtained. The conditions for optimal responses are derived in terms of the bifurcation parameter, the driving frequency, and the noise strength.

  20. Stochastic and Coherence Resonance in Hippocampal Neurons

    DTIC Science & Technology

    2007-11-02

    decreases the signal to noise ratio of subthreshold synaptic inputs. Keywords - Hippocampus , neurons, stochastic resonance I. INTRODUCTION... subthreshold signals in the hippocampus ,” J. Neurophysiology , in press. [3] J. Collins C.C. Chow and T.T. Imboff, “Stochastic resonance without...nonlinear systems whereby the introduction of noise enhances the detection of subthreshold signals. Both computer simulations and experimental

  1. Stochastic resonance in attention control

    NASA Astrophysics Data System (ADS)

    Kitajo, K.; Yamanaka, K.; Ward, L. M.; Yamamoto, Y.

    2006-12-01

    We investigated the beneficial role of noise in a human higher brain function, namely visual attention control. We asked subjects to detect a weak gray-level target inside a marker box either in the left or the right visual field. Signal detection performance was optimized by presenting a low level of randomly flickering gray-level noise between and outside the two possible target locations. Further, we found that an increase in eye movement (saccade) rate helped to compensate for the usual deterioration in detection performance at higher noise levels. To our knowledge, this is the first experimental evidence that noise can optimize a higher brain function which involves distinct brain regions above the level of primary sensory systems -- switching behavior between multi-stable attention states -- via the mechanism of stochastic resonance.

  2. Using Low Levels of Stochastic Vestibular Stimulation to Improve Balance Function

    PubMed Central

    Goel, Rahul; Kofman, Igor; Jeevarajan, Jerome; De Dios, Yiri; Cohen, Helen S.; Bloomberg, Jacob J.; Mulavara, Ajitkumar P.

    2015-01-01

    Low-level stochastic vestibular stimulation (SVS) has been associated with improved postural responses in the medio-lateral (ML) direction, but its effect in improving balance function in both the ML and anterior-posterior (AP) directions has not been studied. In this series of studies, the efficacy of applying low amplitude SVS in 0–30 Hz range between the mastoids in the ML direction on improving cross-planar balance function was investigated. Forty-five (45) subjects stood on a compliant surface with their eyes closed and were instructed to maintain a stable upright stance. Measures of stability of the head, trunk, and whole body were quantified in ML, AP and combined APML directions. Results show that binaural bipolar SVS given in the ML direction significantly improved balance performance with the peak of optimal stimulus amplitude predominantly in the range of 100–500 μA for all the three directions, exhibiting stochastic resonance (SR) phenomenon. Objective perceptual and body motion thresholds as estimates of internal noise while subjects sat on a chair with their eyes closed and were given 1 Hz bipolar binaural sinusoidal electrical stimuli were also measured. In general, there was no significant difference between estimates of perceptual and body motion thresholds. The average optimal SVS amplitude that improved balance performance (peak SVS amplitude normalized to perceptual threshold) was estimated to be 46% in ML, 53% in AP, and 50% in APML directions. A miniature patch-type SVS device may be useful to improve balance function in people with disabilities due to aging, Parkinson’s disease or in astronauts returning from long-duration space flight. PMID:26295807

  3. Stochastic resonance during a polymer translocation process

    NASA Astrophysics Data System (ADS)

    Mondal, Debasish; Muthukumar, Murugappan

    We study the translocation of a flexible polymer in a confined geometry subjected to a time-periodic external drive to explore stochastic resonance. We describe the equilibrium translocation process in terms of a Fokker-Planck description and use a discrete two-state model to describe the effect of the external driving force on the translocation dynamics. We observe that no stochastic resonance is possible if the associated free-energy barrier is purely entropic in nature. The polymer chain experiences a stochastic resonance effect only in presence of an energy threshold in terms of polymer-pore interaction. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.

  4. Stochastic resonance during a polymer translocation process

    NASA Astrophysics Data System (ADS)

    Mondal, Debasish; Muthukumar, M.

    2016-04-01

    We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.

  5. Stochastic resonance during a polymer translocation process.

    PubMed

    Mondal, Debasish; Muthukumar, M

    2016-04-14

    We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.

  6. Stochastic resonance in geomagnetic polarity reversals.

    PubMed

    Consolini, Giuseppe; De Michelis, Paola

    2003-02-07

    Among noise-induced cooperative phenomena a peculiar relevance is played by stochastic resonance. In this paper we offer evidence that geomagnetic polarity reversals may be due to a stochastic resonance process. In detail, analyzing the distribution function P(tau) of polarity residence times (chrons), we found the evidence of a stochastic synchronization process, i.e., a series of peaks in the P(tau) at T(n) approximately (2n+1)T(Omega)/2 with n=0,1,...,j and T(omega) approximately 0.1 Myr. This result is discussed in connection with both the typical time scale of Earth's orbit eccentricity variation and the recent results on the typical time scale of climatic long-term variation.

  7. Stochastic Resonance in Protein Folding Dynamics.

    PubMed

    Davtyan, Aram; Platkov, Max; Gruebele, Martin; Papoian, Garegin A

    2016-05-04

    Although protein folding reactions are usually studied under static external conditions, it is likely that proteins fold in a locally fluctuating cellular environment in vivo. To mimic such behavior in in vitro experiments, the local temperature of the solvent can be modulated either harmonically or using correlated noise. In this study, coarse-grained molecular simulations are used to investigate these possibilities, and it is found that both periodic and correlated random fluctuations of the environment can indeed accelerate folding kinetics if the characteristic frequencies of the applied fluctuations are commensurate with the internal timescale of the folding reaction; this is consistent with the phenomenon of stochastic resonance observed in many other condensed-matter processes. To test this theoretical prediction, the folding dynamics of phosphoglycerate kinase under harmonic temperature fluctuations are experimentally probed using Förster resonance energy transfer fluorescence measurements. To analyze these experiments, a combination of theoretical approaches is developed, including stochastic simulations of folding kinetics and an analytical mean-field kinetic theory. The experimental observations are consistent with the theoretical predictions of stochastic resonance in phosphoglycerate kinase folding. When combined with an alternative experiment on the protein VlsE using a power spectrum analysis, elaborated in Dave et al., ChemPhysChem 2016, 10.1002/cphc.201501041, the overall data overwhelmingly point to the experimental confirmation of stochastic resonance in protein folding dynamics.

  8. Stochastic resonance in Gaussian quantum channels

    NASA Astrophysics Data System (ADS)

    Lupo, Cosmo; Mancini, Stefano; Wilde, Mark M.

    2013-02-01

    We determine conditions for the presence of stochastic resonance in a lossy bosonic channel with a nonlinear, threshold decoding. The stochastic resonance effect occurs if and only if the detection threshold is outside of a ‘forbidden interval’. We show that it takes place in different settings: when transmitting classical messages through a lossy bosonic channel, when transmitting over an entanglement-assisted lossy bosonic channel and when discriminating channels with different loss parameters. Moreover, we consider a setting in which stochastic resonance occurs in the transmission of a qubit over a lossy bosonic channel with a particular encoding and decoding. In all cases, we assume the addition of Gaussian noise to the signal and show that it does not matter who, between sender and receiver, introduces such a noise. Remarkably, different results are obtained when considering a setting for private communication. In this case, the symmetry between sender and receiver is broken and the ‘forbidden interval’ may vanish, leading to the occurrence of stochastic resonance effects for any value of the detection threshold.

  9. Double inverse stochastic resonance with dynamic synapses

    NASA Astrophysics Data System (ADS)

    Uzuntarla, Muhammet; Torres, Joaquin J.; So, Paul; Ozer, Mahmut; Barreto, Ernest

    2017-01-01

    We investigate the behavior of a model neuron that receives a biophysically realistic noisy postsynaptic current based on uncorrelated spiking activity from a large number of afferents. We show that, with static synapses, such noise can give rise to inverse stochastic resonance (ISR) as a function of the presynaptic firing rate. We compare this to the case with dynamic synapses that feature short-term synaptic plasticity and show that the interval of presynaptic firing rate over which ISR exists can be extended or diminished. We consider both short-term depression and facilitation. Interestingly, we find that a double inverse stochastic resonance (DISR), with two distinct wells centered at different presynaptic firing rates, can appear.

  10. Stochastic resonance in a tristable optomechanical system

    NASA Astrophysics Data System (ADS)

    Fan, Bixuan; Xie, Min

    2017-02-01

    In this work we theoretically investigate the stochastic resonance (SR) effect in an optomechanical membrane system subject to two weak signals (one optical field and one mechanical force). The quadratic optomechanical coupling allows us to find a region with tristability where the noise-activated stochastic switching among three stable states occurs and SR phenomena are observed at the cooperation of input signals and noise. We show that the mechanical force and the optical field respectively serve as an additive signal and a multiplicative signal to the membrane position, and they induce completely different SR behaviors. Moreover, when two signals coexist the SR effect can be enhanced, and the beating effect appears in the SR synchronization process with unsynchronized signals.

  11. Noise-free logical stochastic resonance.

    PubMed

    Gupta, Animesh; Sohane, Aman; Kohar, Vivek; Murali, K; Sinha, Sudeshna

    2011-11-01

    The phenomena of logical stochastic resonance (LSR) was demonstrated recently [Phys. Rev. Lett. 102, 104101 (2009)]: namely, when a bistable system is driven by two inputs it consistently yields a response mirroring a logic function of the two inputs in an optimal window of moderate noise. Here we examine the intriguing possibility of obtaining dynamical behavior equivalent to LSR in a noise-free bistable system, subjected only to periodic forcing, such as sinusoidal driving or rectangular pulse trains. We find that such a system, despite having no stochastic influence, also yields phenomena analogous to LSR, in an appropriate window of frequency and amplitude of the periodic forcing. The results are corroborated by circuit experiments.

  12. Spatiotemporal Stochastic Resonance:Theory and Experiment

    NASA Astrophysics Data System (ADS)

    Peter, Jung

    1996-03-01

    The amplification of weak periodic signals in bistable or excitable systems via stochastic resonance has been studied intensively over the last years. We are going one step further and ask: Can noise enhance spatiotemporal patterns in excitable media and can this effect be observed in nature? To this end, we are looking at large, two dimensional arrays of coupled excitable elements. Due to the coupling, excitation can propagate through the array in form of nonlinear waves. We observe target waves, rotating spiral waves and other wave forms. If the coupling between the elements is below a critical threshold, any excitational pattern will die out in the absence of noise. Below this threshold, large scale rotating spiral waves - as they are observed above threshold - can be maintained by a proper level of the noise[1]. Furthermore, their geometric features, such as the curvature can be controlled by the homogeneous noise level[2]. If the noise level is too large, break up of spiral waves and collisions with spontaneously nucleated waves yields spiral turbulence. Driving our array with a spatiotemporal pattern, e.g. a rotating spiral wave, we show that for weak coupling the excitational response of the array shows stochastic resonance - an effect we have termed spatiotemporal stochastic resonance. In the last part of the talk I'll make contact with calcium waves, observed in astrocyte cultures and hippocampus slices[3]. A. Cornell-Bell and collaborators[3] have pointed out the role of calcium waves for long-range glial signaling. We demonstrate the similarity of calcium waves with nonlinear waves in noisy excitable media. The noise level in the tissue is characterized by spontaneous activity and can be controlled by applying neuro-transmitter substances[3]. Noise effects in our model are compared with the effect of neuro-transmitters on calcium waves. [1]P. Jung and G. Mayer-Kress, CHAOS 5, 458 (1995). [2]P. Jung and G. Mayer-Kress, Phys. Rev. Lett.62, 2682 (1995). [3

  13. Stochastic resonance in bistable atomic switches.

    PubMed

    Yoshida, Kenji; Hirakawa, Kazuhiko

    2017-03-24

    We have investigated the conductance of bistable gold atomic switches as a function of periodic input voltages mixed with a random noise. With increasing noise amplitude, the atomic switches biased below the threshold voltage for conductance switching start exhibiting switching in conductance between two stable states. Clear synchronization between the input and output signals is observed when an optimized noise amplitude is mixed with the periodic input voltage, even when the atomic switches are driven by an input voltage as low as approximately 10% of the threshold voltage. The observed behavior can be explained in terms of the stochastic resonance. The results presented here indicate that utilization of noise can dramatically reduce the operation voltage of metal atomic switches.

  14. Stochastic resonance in bistable atomic switches

    NASA Astrophysics Data System (ADS)

    Yoshida, Kenji; Hirakawa, Kazuhiko

    2017-03-01

    We have investigated the conductance of bistable gold atomic switches as a function of periodic input voltages mixed with a random noise. With increasing noise amplitude, the atomic switches biased below the threshold voltage for conductance switching start exhibiting switching in conductance between two stable states. Clear synchronization between the input and output signals is observed when an optimized noise amplitude is mixed with the periodic input voltage, even when the atomic switches are driven by an input voltage as low as approximately 10% of the threshold voltage. The observed behavior can be explained in terms of the stochastic resonance. The results presented here indicate that utilization of noise can dramatically reduce the operation voltage of metal atomic switches.

  15. Stochastic and coherence resonance in an in silico neural model.

    PubMed

    Chiu, Alan W L; Bardakjian, Berj L

    2004-05-01

    We show that it is possible for chaotic systems to display the main features of stochastic and coherence resonance. In particular, a model of coupled nonlinear oscillators which emulates the transmembrane voltage activities in CA3 neurons, operating in a chaotic regime and in the presence of noise, can exhibit coherence resonance and stochastic resonance. Certain firing frequencies become more "rhythmic" for some optimal values of noise intensity. The effect of noise in different coupling pathways is investigated. We found that the effect of coherence resonance and stochastic resonance are more prominent if noise is presented in either electric field or gap junction coupling pathways. Frequency sensitivity of the model is investigated as a preliminary step in illustrating the principles of possible epileptic seizure control strategies using "chaos control" concepts. Significant effects of stochastic resonance are observed in the 4-8 Hz range. Weaker effects can be found in the 1-4 Hz and 8-10 Hz ranges whereas 0.5 Hz does not exhibit any resonance phenomenon. Our results suggest that: (a) Stochastic resonance could enhance the intrinsic 4-8 Hz rhythms in CA3 neurons more prominently via field coupling pathways. It could also help explain why some reported seizure control strategies using pulse-trains would only be effective at 0.5 Hz. (b) Stochastic resonance-like behavior can occur in the gamma range only if noise is presented via chemical synaptic pathways.

  16. City traffic jam relief by stochastic resonance

    NASA Astrophysics Data System (ADS)

    Castillo, F.; Toledo, B. A.; Muñoz, V.; Rogan, J.; Zarama, R.; Kiwi, M.; Valdivia, J. A.

    2014-06-01

    We simulate traffic in a city by means of the evolution of a row of interacting cars, using a cellular automaton model, in a sequence of traffic lights synchronized by a "green wave". When our initial condition is a small density jammed state, its evolution shows the expected scaling laws close to the synchronization resonance, with a uniform car density along the street. However, for an initial large density jammed state, we observe density variations along the streets, which results in the breakdown of the scaling laws. This spatial disorder corresponds to a different attractor of the system. As we include velocity perturbations in the dynamics of the cars, all these attractors converge to a statistically equivalent system for all initial jammed densities. However, this emergent state shows a stochastic resonance-like behavior in which the average traffic velocity increases with respect to that of the system without noise, for several initial jammed densities. This result may help in the understanding of dynamics of traffic jams in cities.

  17. Random-order fractional bistable system and its stochastic resonance

    NASA Astrophysics Data System (ADS)

    Gao, Shilong; Zhang, Li; Liu, Hui; Kan, Bixia

    2017-01-01

    In this paper, the diffusion motion of Brownian particles in a viscous liquid suffering from stochastic fluctuations of the external environment is modeled as a random-order fractional bistable equation, and as a typical nonlinear dynamic behavior, the stochastic resonance phenomena in this system are investigated. At first, the derivation process of the random-order fractional bistable system is given. In particular, the random-power-law memory is deeply discussed to obtain the physical interpretation of the random-order fractional derivative. Secondly, the stochastic resonance evoked by random-order and external periodic force is mainly studied by numerical simulation. In particular, the frequency shifting phenomena of the periodical output are observed in SR induced by the excitation of the random order. Finally, the stochastic resonance of the system under the double stochastic excitations of the random order and the internal color noise is also investigated.

  18. Inverse Stochastic Resonance in Cerebellar Purkinje Cells

    PubMed Central

    Häusser, Michael; Gutkin, Boris S.; Roth, Arnd

    2016-01-01

    Purkinje neurons play an important role in cerebellar computation since their axons are the only projection from the cerebellar cortex to deeper cerebellar structures. They have complex internal dynamics, which allow them to fire spontaneously, display bistability, and also to be involved in network phenomena such as high frequency oscillations and travelling waves. Purkinje cells exhibit type II excitability, which can be revealed by a discontinuity in their f-I curves. We show that this excitability mechanism allows Purkinje cells to be efficiently inhibited by noise of a particular variance, a phenomenon known as inverse stochastic resonance (ISR). While ISR has been described in theoretical models of single neurons, here we provide the first experimental evidence for this effect. We find that an adaptive exponential integrate-and-fire model fitted to the basic Purkinje cell characteristics using a modified dynamic IV method displays ISR and bistability between the resting state and a repetitive activity limit cycle. ISR allows the Purkinje cell to operate in different functional regimes: the all-or-none toggle or the linear filter mode, depending on the variance of the synaptic input. We propose that synaptic noise allows Purkinje cells to quickly switch between these functional regimes. Using mutual information analysis, we demonstrate that ISR can lead to a locally optimal information transfer between the input and output spike train of the Purkinje cell. These results provide the first experimental evidence for ISR and suggest a functional role for ISR in cerebellar information processing. PMID:27541958

  19. Stochastic resonance in neuron models: Endogenous stimulation revisited

    NASA Astrophysics Data System (ADS)

    Plesser, Hans E.; Geisel, Theo

    2001-03-01

    The paradigm of stochastic resonance (SR)-the idea that signal detection and transmission may benefit from noise-has met with great interest in both physics and the neurosciences. We investigate here the consequences of reducing the dynamics of a periodically driven neuron to a renewal process (stimulation with reset or endogenous stimulation). This greatly simplifies the mathematical analysis, but we show that stochastic resonance as reported earlier occurs in this model only as a consequence of the reduced dynamics.

  20. A microprocessor-based multichannel subsensory stochastic resonance electrical stimulator.

    PubMed

    Chang, Gwo-Ching

    2013-01-01

    Stochastic resonance electrical stimulation is a novel intervention which provides potential benefits for improving postural control ability in the elderly, those with diabetic neuropathy, and stroke patients. In this paper, a microprocessor-based subsensory white noise electrical stimulator for the applications of stochastic resonance stimulation is developed. The proposed stimulator provides four independent programmable stimulation channels with constant-current output, possesses linear voltage-to-current relationship, and has two types of stimulation modes, pulse amplitude and width modulation.

  1. Stochastic P-bifurcation and stochastic resonance in a noisy bistable fractional-order system

    NASA Astrophysics Data System (ADS)

    Yang, J. H.; Sanjuán, Miguel A. F.; Liu, H. G.; Litak, G.; Li, X.

    2016-12-01

    We investigate the stochastic response of a noisy bistable fractional-order system when the fractional-order lies in the interval (0, 2]. We focus mainly on the stochastic P-bifurcation and the phenomenon of the stochastic resonance. We compare the generalized Euler algorithm and the predictor-corrector approach which are commonly used for numerical calculations of fractional-order nonlinear equations. Based on the predictor-corrector approach, the stochastic P-bifurcation and the stochastic resonance are investigated. Both the fractional-order value and the noise intensity can induce an stochastic P-bifurcation. The fractional-order may lead the stationary probability density function to turn from a single-peak mode to a double-peak mode. However, the noise intensity may transform the stationary probability density function from a double-peak mode to a single-peak mode. The stochastic resonance is investigated thoroughly, according to the linear and the nonlinear response theory. In the linear response theory, the optimal stochastic resonance may occur when the value of the fractional-order is larger than one. In previous works, the fractional-order is usually limited to the interval (0, 1]. Moreover, the stochastic resonance at the subharmonic frequency and the superharmonic frequency are investigated respectively, by using the nonlinear response theory. When it occurs at the subharmonic frequency, the resonance may be strong and cannot be ignored. When it occurs at the superharmonic frequency, the resonance is weak. We believe that the results in this paper might be useful for the signal processing of nonlinear systems.

  2. Constructive role of Brownian motion: Brownian motors and Stochastic Resonance

    NASA Astrophysics Data System (ADS)

    Hänggi, Peter

    2005-03-01

    Noise is usually thought of as the enemy of order rather as a constructive influence. For the phenomena of Stochastic Resonance [1] and Brownian motors [2], however, stochastic noise can play a beneficial role in enhancing detection and/or facilitating directed transmission of information in absence of biasing forces. Brownian motion assisted Stochastic Resonance finds useful applications in physical, technological, biological and biomedical contexts [1,3]. The basic principles that underpin Stochastic Resonance are elucidated and novel applications for nonlinear classical and quantum systems will be addressed. The presence of non-equilibrium disturbances enables to rectify Brownian motion so that quantum and classical objects can be directed around on a priori designed routes in biological and physical systems (Brownian motors). In doing so, the energy from the haphazard motion of (quantum) Brownian particles is extracted to perform useful work against an external load. This very concept together with first experimental realizations are discussed [2,4,5]. [1] L. Gammaitoni, P. Hä'nggi, P. Jung and F. Marchesoni, Stochastic Resonance, Rev. Mod. Phys. 70, 223 (1998).[2] R. D. Astumian and P. Hä'nggi, Brownian motors, Physics Today 55 (11), 33 (2002).[3] P. Hä'nggi, Stochastic Resonace in Physics and Biology, ChemPhysChem 3, 285 (2002).[4] H. Linke, editor, Special Issue on Brownian Motors, Applied Physics A 75, No. 2 (2002).[5] P. Hä'nggi, F. Marchesoni, F. Nori, Brownian motors, Ann. Physik (Leipzig) 14, xxx (2004); cond-mat/0410033.

  3. Coherent signal amplification in bistable nanomechanical oscillators by stochastic resonance

    NASA Astrophysics Data System (ADS)

    Badzey, Robert L.; Mohanty, Pritiraj

    2005-10-01

    Stochastic resonance is a counterintuitive concept: the addition of noise to a noisy system induces coherent amplification of its response. First suggested as a mechanism for the cyclic recurrence of ice ages, stochastic resonance has been seen in a wide variety of macroscopic physical systems: bistable ring lasers, superconducting quantum interference devices (SQUIDs), magnetoelastic ribbons and neurophysiological systems such as the receptors in crickets and crayfish. Although fundamentally important as a mechanism of coherent signal amplification, stochastic resonance has yet to be observed in nanoscale systems. Here we report the observation of stochastic resonance in bistable nanomechanical silicon oscillators. Our nanomechanical systems consist of beams that are clamped at each end and driven into transverse oscillation with the use of a radiofrequency source. Modulation of the source induces controllable switching of the beams between two stable, distinct states. We observe that the addition of white noise causes a marked amplification of the signal strength. Stochastic resonance in nanomechanical systems could have a function in the realization of controllable high-speed nanomechanical memory cells, and paves the way for exploring macroscopic quantum coherence and tunnelling.

  4. Tracking stochastic resonance curves using an assisted reference model

    SciTech Connect

    Calderón Ramírez, Mario; Rico Martínez, Ramiro; Parmananda, P.

    2015-06-15

    The optimal noise amplitude for Stochastic Resonance (SR) is located employing an Artificial Neural Network (ANN) reference model with a nonlinear predictive capability. A modified Kalman Filter (KF) was coupled to this reference model in order to compensate for semi-quantitative forecast errors. Three manifestations of stochastic resonance, namely, Periodic Stochastic Resonance (PSR), Aperiodic Stochastic Resonance (ASR), and finally Coherence Resonance (CR) were considered. Using noise amplitude as the control parameter, for the case of PSR and ASR, the cross-correlation curve between the sub-threshold input signal and the system response is tracked. However, using the same parameter the Normalized Variance curve is tracked for the case of CR. The goal of the present work is to track these curves and converge to their respective extremal points. The ANN reference model strategy captures and subsequently predicts the nonlinear features of the model system while the KF compensates for the perturbations inherent to the superimposed noise. This technique, implemented in the FitzHugh-Nagumo model, enabled us to track the resonance curves and eventually locate their optimal (extremal) values. This would yield the optimal value of noise for the three manifestations of the SR phenomena.

  5. Tracking stochastic resonance curves using an assisted reference model

    NASA Astrophysics Data System (ADS)

    Calderón Ramírez, Mario; Rico Martínez, Ramiro; Ramírez Álvarez, Elizeth; Parmananda, P.

    2015-06-01

    The optimal noise amplitude for Stochastic Resonance (SR) is located employing an Artificial Neural Network (ANN) reference model with a nonlinear predictive capability. A modified Kalman Filter (KF) was coupled to this reference model in order to compensate for semi-quantitative forecast errors. Three manifestations of stochastic resonance, namely, Periodic Stochastic Resonance (PSR), Aperiodic Stochastic Resonance (ASR), and finally Coherence Resonance (CR) were considered. Using noise amplitude as the control parameter, for the case of PSR and ASR, the cross-correlation curve between the sub-threshold input signal and the system response is tracked. However, using the same parameter the Normalized Variance curve is tracked for the case of CR. The goal of the present work is to track these curves and converge to their respective extremal points. The ANN reference model strategy captures and subsequently predicts the nonlinear features of the model system while the KF compensates for the perturbations inherent to the superimposed noise. This technique, implemented in the FitzHugh-Nagumo model, enabled us to track the resonance curves and eventually locate their optimal (extremal) values. This would yield the optimal value of noise for the three manifestations of the SR phenomena.

  6. Controlling of explicit internal signal stochastic resonance by external signal

    NASA Astrophysics Data System (ADS)

    Li, Ya Ping; Wang, Pin; Li, Qian Shu

    2004-09-01

    Explicit internal signal stochastic resonance (EISSR) is investigated in a model of energy transduction of molecular machinery when noise is added to the region of oscillation in the presence of external signal (ES). It is found that EISSR could be controlled, i.e., enhanced or suppressed by adjusting frequency (ωe) and amplitude (A) of ES, and that there exits an optimal frequency for ES, which makes EISSR strength reach the maximum. Meanwhile, a critical amplitude (Ac) is found, which is a threshold of occurrence of EISSR. Finally, the difference and similarity between EISSR and IISSR (implicit internal signal stochastic resonance) are discussed.

  7. Delayed-feedback chimera states: Forced multiclusters and stochastic resonance

    NASA Astrophysics Data System (ADS)

    Semenov, V.; Zakharova, A.; Maistrenko, Y.; Schöll, E.

    2016-07-01

    A nonlinear oscillator model with negative time-delayed feedback is studied numerically under external deterministic and stochastic forcing. It is found that in the unforced system complex partial synchronization patterns like chimera states as well as salt-and-pepper-like solitary states arise on the route from regular dynamics to spatio-temporal chaos. The control of the dynamics by external periodic forcing is demonstrated by numerical simulations. It is shown that one-cluster and multi-cluster chimeras can be achieved by adjusting the external forcing frequency to appropriate resonance conditions. If a stochastic component is superimposed to the deterministic external forcing, chimera states can be induced in a way similar to stochastic resonance, they appear, therefore, in regimes where they do not exist without noise.

  8. Stochastic resonance in feedforward acupuncture networks

    NASA Astrophysics Data System (ADS)

    Qin, Ying-Mei; Wang, Jiang; Men, Cong; Deng, Bin; Wei, Xi-Le; Yu, Hai-Tao; Chan, Wai-Lok

    2014-10-01

    Effects of noises and some other network properties on the weak signal propagation are studied systematically in feedforward acupuncture networks (FFN) based on FitzHugh-Nagumo neuron model. It is found that noises with medium intensity can enhance signal propagation and this effect can be further increased by the feedforward network structure. Resonant properties in the noisy network can also be altered by several network parameters, such as heterogeneity, synapse features, and feedback connections. These results may also provide a novel potential explanation for the propagation of acupuncture signal.

  9. Reconstruction of pulse noisy images via stochastic resonance

    PubMed Central

    Han, Jing; Liu, Hongjun; Sun, Qibing; Huang, Nan

    2015-01-01

    We investigate a practical technology for reconstructing nanosecond pulse noisy images via stochastic resonance, which is based on the modulation instability. A theoretical model of this method for optical pulse signal is built to effectively recover the pulse image. The nanosecond noise-hidden images grow at the expense of noise during the stochastic resonance process in a photorefractive medium. The properties of output images are mainly determined by the input signal-to-noise intensity ratio, the applied voltage across the medium, and the correlation length of noise background. A high cross-correlation gain is obtained by optimizing these parameters. This provides a potential method for detecting low-level or hidden pulse images in various imaging applications. PMID:26067911

  10. Stochastic resonance in tristable system induced by dichotomous noise

    NASA Astrophysics Data System (ADS)

    Shi, Peiming; Su, Xiao; Han, Dongying

    2016-11-01

    Stochastic resonance (SR) of a tristable system driven by dichotomous noise (DN) is investigated firstly by the mean signal-to-noise ratio gain (SNR-GM). Utilizing an efficiently numerical algorithm, we acquire the asymmetric DN accurately. Then the system responses and the SNR-GM as the signatures of the stochastic resonance are calculated by the fourth-order Runge-Kutta algorithm. It is founded that the change of system parameters a and c in a certain range can induce SR phenomenon. Moreover, with the increase of parameter c, the amplitude of SNR-GM increases and shows the trend of moving to the left. For the different state values of the symmetric DN, the SNR-GM will increase with the increase of state value a1 and b1 but only a highest peak and the interval of SR shift to the left. However, with the increase of forcing frequency, the SNR-GM decreases and the interval of SR moves to right. In addition to, the highest peak of SNR-GM will decrease with the increase of periodic signal amplitude. These results provide a reliable basis for how to realize the parameter selection of stochastic resonance in tristable system driven by DN.

  11. Stochastic resonance-a nonlinear control theory interpretation

    NASA Astrophysics Data System (ADS)

    Repperger, D. W.; Farris, K. A.

    2010-07-01

    Stochastic resonance (SR) is an effect that has been known (Benzi, R., Sutera, A., and Vulpiani, A. (1981), 'The Mechanism of Stochastic Resonance', Journal of Physics, A14, L453-L457) for almost three decades and has been extensively studied in biology, statistics, signal processing and in numerous other eclectic areas (Wiesenfeld, K., and Moss, F. (1995), 'Stochastic Resonance and the Benefits of Noise: From Ice Ages to Crayfish and Squids', Nature, 373, 33-36). Herein, a nonlinear control theory analysis is conducted on how to better understand the class of systems that may exhibit the SR effect. Using nonlinear control theory methods, equilibrium points are manipulated to create the SR response (similar to shaping dynamical response in a phase plane). From this approach, a means of synthesising and designing the appropriate class of nonlinear systems is introduced. New types of nonlinear dynamics that demonstrate the SR effects are discovered, which may have utility in control theory as well as in many diverse applications. A numerical simulation illustrates some powerful attributes of these systems.

  12. Effect of the heterogeneous neuron and information transmission delay on stochastic resonance of neuronal networks

    NASA Astrophysics Data System (ADS)

    Wang, Qingyun; Zhang, Honghui; Chen, Guanrong

    2012-12-01

    We study the effect of heterogeneous neuron and information transmission delay on stochastic resonance of scale-free neuronal networks. For this purpose, we introduce the heterogeneity to the specified neuron with the highest degree. It is shown that in the absence of delay, an intermediate noise level can optimally assist spike firings of collective neurons so as to achieve stochastic resonance on scale-free neuronal networks for small and intermediate αh, which plays a heterogeneous role. Maxima of stochastic resonance measure are enhanced as αh increases, which implies that the heterogeneity can improve stochastic resonance. However, as αh is beyond a certain large value, no obvious stochastic resonance can be observed. If the information transmission delay is introduced to neuronal networks, stochastic resonance is dramatically affected. In particular, the tuned information transmission delay can induce multiple stochastic resonance, which can be manifested as well-expressed maximum in the measure for stochastic resonance, appearing every multiple of one half of the subthreshold stimulus period. Furthermore, we can observe that stochastic resonance at odd multiple of one half of the subthreshold stimulus period is subharmonic, as opposed to the case of even multiple of one half of the subthreshold stimulus period. More interestingly, multiple stochastic resonance can also be improved by the suitable heterogeneous neuron. Presented results can provide good insights into the understanding of the heterogeneous neuron and information transmission delay on realistic neuronal networks.

  13. Effect of the heterogeneous neuron and information transmission delay on stochastic resonance of neuronal networks.

    PubMed

    Wang, Qingyun; Zhang, Honghui; Chen, Guanrong

    2012-12-01

    We study the effect of heterogeneous neuron and information transmission delay on stochastic resonance of scale-free neuronal networks. For this purpose, we introduce the heterogeneity to the specified neuron with the highest degree. It is shown that in the absence of delay, an intermediate noise level can optimally assist spike firings of collective neurons so as to achieve stochastic resonance on scale-free neuronal networks for small and intermediate α(h), which plays a heterogeneous role. Maxima of stochastic resonance measure are enhanced as α(h) increases, which implies that the heterogeneity can improve stochastic resonance. However, as α(h) is beyond a certain large value, no obvious stochastic resonance can be observed. If the information transmission delay is introduced to neuronal networks, stochastic resonance is dramatically affected. In particular, the tuned information transmission delay can induce multiple stochastic resonance, which can be manifested as well-expressed maximum in the measure for stochastic resonance, appearing every multiple of one half of the subthreshold stimulus period. Furthermore, we can observe that stochastic resonance at odd multiple of one half of the subthreshold stimulus period is subharmonic, as opposed to the case of even multiple of one half of the subthreshold stimulus period. More interestingly, multiple stochastic resonance can also be improved by the suitable heterogeneous neuron. Presented results can provide good insights into the understanding of the heterogeneous neuron and information transmission delay on realistic neuronal networks.

  14. Intrinsic periodic and aperiodic stochastic resonance in an electrochemical cell

    NASA Astrophysics Data System (ADS)

    Tiwari, Ishant; Phogat, Richa; Parmananda, P.; Ocampo-Espindola, J. L.; Rivera, M.

    2016-08-01

    In this paper we show the interaction of a composite of a periodic or aperiodic signal and intrinsic electrochemical noise with the nonlinear dynamics of an electrochemical cell configured to study the corrosion of iron in an acidic media. The anodic voltage setpoint (V0) in the cell is chosen such that the anodic current (I ) exhibits excitable fixed point behavior in the absence of noise. The subthreshold periodic (aperiodic) signal consists of a train of rectangular pulses with a fixed amplitude and width, separated by regular (irregular) time intervals. The irregular time intervals chosen are of deterministic and stochastic origins. The amplitude of the intrinsic internal noise, regulated by the concentration of chloride ions, is then monotonically increased, and the provoked dynamics are analyzed. The signal to noise ratio and the cross-correlation coefficient versus the chloride ions' concentration curves have a unimodal shape indicating the emergence of an intrinsic periodic or aperiodic stochastic resonance. The abscissa for the maxima of these unimodal curves correspond to the optimum value of intrinsic noise where maximum regularity of the invoked dynamics is observed. In the particular case of the intrinsic periodic stochastic resonance, the scanning electron microscope images for the electrode metal surfaces are shown for certain values of chloride ions' concentrations. These images, qualitatively, corroborate the emergence of order as a result of the interaction between the nonlinear dynamics and the composite signal.

  15. Cyclotron resonance effects on stochastic acceleration of light ionospheric ions

    NASA Technical Reports Server (NTRS)

    Singh, N.; Schunk, R. W.; Sojka, J. J.

    1982-01-01

    The production of energetic ions with conical pitch angle distributions along the auroral field lines is a subject of considerable current interest. There are several theoretical treatments showing the acceleration (heating) of the ions by ion cyclotron waves. The quasi-linear theory predicts no acceleration when the ions are nonresonant. In the present investigation, it is demonstrated that the cyclotron resonances are not crucial for the transverse acceleration of ions by ion cyclotron waves. It is found that transverse energization of ionospheric ions, such as He(+), He(++), O(++), and O(+), is possible by an Electrostatic Hydrogen Cyclotron (EHC) wave even in the absence of cyclotron resonance. The mechanism of acceleration is the nonresonant stochastic heating. However, when there are resonant ions both the total energy gain and the number of accelerated ions increase with increasing parallel wave number.

  16. Optomechanically induced stochastic resonance and chaos transfer between optical fields

    NASA Astrophysics Data System (ADS)

    Monifi, Faraz; Zhang, Jing; Özdemir, Şahin Kaya; Peng, Bo; Liu, Yu-Xi; Bo, Fang; Nori, Franco; Yang, Lan

    2016-06-01

    Chaotic dynamics has been reported in many physical systems and has affected almost every field of science. Chaos involves hypersensitivity to the initial conditions of a system and introduces unpredictability into its output. Thus, it is often unwanted. Interestingly, the very same features make chaos a powerful tool to suppress decoherence, achieve secure communication and replace background noise in stochastic resonance—a counterintuitive concept that a system's ability to transfer information can be coherently amplified by adding noise. Here, we report the first demonstration of chaos-induced stochastic resonance in an optomechanical system, as well as the optomechanically mediated chaos transfer between two optical fields such that they follow the same route to chaos. These results will contribute to the understanding of nonlinear phenomena and chaos in optomechanical systems, and may find applications in the chaotic transfer of information and for improving the detection of otherwise undetectable signals in optomechanical systems.

  17. Stochastic resonance in a generalized Von Foerster population growth model

    SciTech Connect

    Lumi, N.; Mankin, R.

    2014-11-12

    The stochastic dynamics of a population growth model, similar to the Von Foerster model for human population, is studied. The influence of fluctuating environment on the carrying capacity is modeled as a multiplicative dichotomous noise. It is established that an interplay between nonlinearity and environmental fluctuations can cause single unidirectional discontinuous transitions of the mean population size versus the noise amplitude, i.e., an increase of noise amplitude can induce a jump from a state with a moderate number of individuals to that with a very large number, while by decreasing the noise amplitude an opposite transition cannot be effected. An analytical expression of the mean escape time for such transitions is found. Particularly, it is shown that the mean transition time exhibits a strong minimum at intermediate values of noise correlation time, i.e., the phenomenon of stochastic resonance occurs. Applications of the results in ecology are also discussed.

  18. Stochastic dipolar recoupling in nuclear magnetic resonance of solids

    PubMed Central

    Tycko, Robert

    2008-01-01

    I describe a nuclear magnetic resonance (NMR) technique, called stochastic dipolar recoupling (SDR), that permits continuous experimental control of the character of spin dynamics between coherent and incoherent limits in a system of magnetic dipole-coupled nuclei. In the fully incoherent limit of SDR, spin polarization transfers occur at distance-dependent rates without the quantum mechanical interferences among pairwise dipole-dipole couplings that often limit the feasibility or precision of structural studies of solids by NMR. In addition to facilitating structural studies, SDR represents a possible route to experimental studies of effects of decoherence on the dynamics of quantum many-body systems. PMID:17995438

  19. Inverse stochastic resonance in electroconvection by multiplicative colored noise

    NASA Astrophysics Data System (ADS)

    Huh, Jong-Hoon

    2016-11-01

    A kind of inverse stochastic resonance (ISR) observed in ac-driven electroconvection (EC) in a nematic liquid crystal is presented. In successive pattern evolutions by increasing noise intensity VN, a typical EC (with a normalized amplitude A0=1 at VN=0 ) disappears (A0→0 ) , and then the rest state (A0=0 ) reenters into the EC (A0=1 ); eventually, it develops into complicated EC (A0>1 ) . The reversed bell-shaped behavior of A0(VN) is evidence of ISR. The present ISR may be explained by taking into account colored noise characterized by its intensity and correlation time.

  20. Stochastic dipolar recoupling in nuclear magnetic resonance of solids.

    PubMed

    Tycko, Robert

    2007-11-02

    I describe a nuclear magnetic resonance (NMR) technique, called stochastic dipolar recoupling (SDR), that permits continuous experimental control of the character of spin dynamics between coherent and incoherent limits in a system of magnetic dipole-coupled nuclei. In the fully incoherent limit of SDR, spin polarization transfers occur at distance-dependent rates without the quantum mechanical interferences among pairwise dipole-dipole couplings that often limit the feasibility or precision of structural studies of solids by NMR. In addition to facilitating structural studies, SDR represents a possible route to experimental studies of effects of decoherence on the dynamics of quantum many-body systems.

  1. Stochastic Dipolar Recoupling in Nuclear Magnetic Resonance of Solids

    SciTech Connect

    Tycko, Robert

    2007-11-02

    I describe a nuclear magnetic resonance (NMR) technique, called stochastic dipolar recoupling (SDR), that permits continuous experimental control of the character of spin dynamics between coherent and incoherent limits in a system of magnetic dipole-coupled nuclei. In the fully incoherent limit of SDR, spin polarization transfers occur at distance-dependent rates without the quantum mechanical interferences among pairwise dipole-dipole couplings that often limit the feasibility or precision of structural studies of solids by NMR. In addition to facilitating structural studies, SDR represents a possible route to experimental studies of effects of decoherence on the dynamics of quantum many-body system000.

  2. Stochastic resonance with colored noise for neural signal detection.

    PubMed

    Duan, Fabing; Chapeau-Blondeau, François; Abbott, Derek

    2014-01-01

    We analyze signal detection with nonlinear test statistics in the presence of colored noise. In the limits of small signal and weak noise correlation, the optimal test statistic and its performance are derived under general conditions, especially concerning the type of noise. We also analyze, for a threshold nonlinearity-a key component of a neural model, the conditions for noise-enhanced performance, establishing that colored noise is superior to white noise for detection. For a parallel array of nonlinear elements, approximating neurons, we demonstrate even broader conditions allowing noise-enhanced detection, via a form of suprathreshold stochastic resonance.

  3. Effects of stochastic vestibular galvanic stimulation and LDOPA on balance and motor symptoms in patients with Parkinson’s disease

    PubMed Central

    Samoudi, Ghazaleh; Jivegård, Maria; Mulavara, Ajitkumar P.; Bergquist, Filip

    2017-01-01

    Background Balance problems contribute to reduced quality of life in Parkinson’s disease (PD) and available treatments are often insufficient for treating axial and postural motor symptoms. Objective To investigate the safety of use and possible effects of stochastic vestibular stimulation (SVS) alone and combined with LDOPA in patients with PD. Methods SVS or sham stimulation was administered to 10 PD patients in a double-blind placebo controlled cross-over pilot study. Motor symptoms and balance were evaluated in a defined off-medication state and after a 200 mg test dose of LDOPA, using UPDRS-III, Posturo- Locomotor-Manual (PLM) movement times (MT), static posturography and force plate measurements of the correcting response to a balance perturbation. Results Patients did not detect when SVS was active, but SVS increased nausea after LDOPA in two patients. Mixed model analysis demonstrated that SVS improved balance corrections after a backward perturbation and shortened the postural response time. In static posturography there was significant interaction between effects of SVS, medication and proprioceptive input (standing on foam vs. on hard support) and SVS decreased the total sway-path with eyes closed and off medication. As expected, LDOPA improved the UPDRS-III scores and MT. There was an interaction between the effect of SVS and LDOPA on UPDRS-III partly because of reduced UPDRS-III scores with SVS in the off-medication state. Conclusions Short term use of SVS is safe, improves corrective postural responses and may have a small positive effect on motor symptoms in PD patients off treatment. PMID:25573070

  4. Planetary gearbox fault diagnosis using an adaptive stochastic resonance method

    NASA Astrophysics Data System (ADS)

    Lei, Yaguo; Han, Dong; Lin, Jing; He, Zhengjia

    2013-07-01

    Planetary gearboxes are widely used in aerospace, automotive and heavy industry applications due to their large transmission ratio, strong load-bearing capacity and high transmission efficiency. The tough operation conditions of heavy duty and intensive impact load may cause gear tooth damage such as fatigue crack and teeth missed etc. The challenging issues in fault diagnosis of planetary gearboxes include selection of sensitive measurement locations, investigation of vibration transmission paths and weak feature extraction. One of them is how to effectively discover the weak characteristics from noisy signals of faulty components in planetary gearboxes. To address the issue in fault diagnosis of planetary gearboxes, an adaptive stochastic resonance (ASR) method is proposed in this paper. The ASR method utilizes the optimization ability of ant colony algorithms and adaptively realizes the optimal stochastic resonance system matching input signals. Using the ASR method, the noise may be weakened and weak characteristics highlighted, and therefore the faults can be diagnosed accurately. A planetary gearbox test rig is established and experiments with sun gear faults including a chipped tooth and a missing tooth are conducted. And the vibration signals are collected under the loaded condition and various motor speeds. The proposed method is used to process the collected signals and the results of feature extraction and fault diagnosis demonstrate its effectiveness.

  5. PULSAR STATE SWITCHING FROM MARKOV TRANSITIONS AND STOCHASTIC RESONANCE

    SciTech Connect

    Cordes, J. M.

    2013-09-20

    Markov processes are shown to be consistent with metastable states seen in pulsar phenomena, including intensity nulling, pulse-shape mode changes, subpulse drift rates, spin-down rates, and X-ray emission, based on the typically broad and monotonic distributions of state lifetimes. Markovianity implies a nonlinear magnetospheric system in which state changes occur stochastically, corresponding to transitions between local minima in an effective potential. State durations (though not transition times) are thus largely decoupled from the characteristic timescales of various magnetospheric processes. Dyadic states are common but some objects show at least four states with some transitions forbidden. Another case is the long-term intermittent pulsar B1931+24 that has binary radio-emission and torque states with wide, but non-monotonic duration distributions. It also shows a quasi-period of 38 ± 5 days in a 13 yr time sequence, suggesting stochastic resonance in a Markov system with a forcing function that could be strictly periodic or quasi-periodic. Nonlinear phenomena are associated with time-dependent activity in the acceleration region near each magnetic polar cap. The polar-cap diode is altered by feedback from the outer magnetosphere and by return currents from the equatorial region outside the light cylinder that may also cause the neutron star to episodically charge and discharge. Orbital perturbations of a disk or current sheet provide a natural periodicity for the forcing function in the stochastic-resonance interpretation of B1931+24. Disk dynamics may introduce additional timescales in observed phenomena. Future work can test the Markov interpretation, identify which pulsar types have a propensity for state changes, and clarify the role of selection effects.

  6. Delay-induced multiple stochastic resonances on scale-free neuronal networks.

    PubMed

    Wang, Qingyun; Perc, Matjaz; Duan, Zhisheng; Chen, Guanrong

    2009-06-01

    We study the effects of periodic subthreshold pacemaker activity and time-delayed coupling on stochastic resonance over scale-free neuronal networks. As the two extreme options, we introduce the pacemaker, respectively, to the neuron with the highest degree and to one of the neurons with the lowest degree within the network, but we also consider the case when all neurons are exposed to the periodic forcing. In the absence of delay, we show that an intermediate intensity of noise is able to optimally assist the pacemaker in imposing its rhythm on the whole ensemble, irrespective to its placing, thus providing evidences for stochastic resonance on the scale-free neuronal networks. Interestingly thereby, if the forcing in form of a periodic pulse train is introduced to all neurons forming the network, the stochastic resonance decreases as compared to the case when only a single neuron is paced. Moreover, we show that finite delays in coupling can significantly affect the stochastic resonance on scale-free neuronal networks. In particular, appropriately tuned delays can induce multiple stochastic resonances independently of the placing of the pacemaker, but they can also altogether destroy stochastic resonance. Delay-induced multiple stochastic resonances manifest as well-expressed maxima of the correlation measure, appearing at every multiple of the pacemaker period. We argue that fine-tuned delays and locally active pacemakers are vital for assuring optimal conditions for stochastic resonance on complex neuronal networks.

  7. Noise-hidden signal recovery via stochastic resonance in the SOI waveguide resonator

    NASA Astrophysics Data System (ADS)

    Sun, Heng; Liu, Hongjun; Sun, Qibing; Huang, Nan; Wang, Zhaolu; Han, Jing; Li, Shaopeng

    2016-02-01

    We propose a method to recover weak pulse signals buried in noise via stochastic resonance (SR) based on optical bistability induced by the free-carrier dispersion effect in the silicon-on-insulator (SOI) waveguide resonator. The bistable system threshold is determined by the resonator parameters including the waveguide length, mirror reflectivity, and the free-carrier lifetime. A signal with different power levels can be detected by changing the free-carrier lifetime using a reverse-biased p-i-n junction embedded in the SOI waveguide. The influence of the system parameters on the SR is quantitatively analyzed by calculating the cross-correlation coefficient between the input and output signals. A cross-correlation gain of 5.6 is obtained by optimizing the system parameters of the SOI waveguide resonator. The results show the potential of using this structure to reconstruct and extract weak signals in all-optical integrated systems.

  8. A neuron model of stochastic resonance using rectangular pulse trains.

    PubMed

    Danziger, Zachary; Grill, Warren M

    2015-02-01

    Stochastic resonance (SR) is the enhanced representation of a weak input signal by the addition of an optimal level of broadband noise to a nonlinear (threshold) system. Since its discovery in the 1980s the domain of input signals shown to be applicable to SR has greatly expanded, from strictly periodic inputs to now nearly any aperiodic forcing function. The perturbations (noise) used to generate SR have also expanded, from white noise to now colored noise or vibrational forcing. This study demonstrates that a new class of perturbations can achieve SR, namely, series of stochastically generated biphasic pulse trains. Using these pulse trains as 'noise' we show that a Hodgkin Huxley model neuron exhibits SR behavior when detecting weak input signals. This result is of particular interest to neuroscience because nearly all artificial neural stimulation is implemented with square current or voltage pulses rather than broadband noise, and this new method may facilitate the translation of the performance gains achievable through SR to neural prosthetics.

  9. Pulse noise-hidden image reconstruction and visualization via stochastic resonance

    PubMed Central

    Sun, Qibing; Liu, Hongjun; Huang, Nan; Wang, Zhaolu; Han, Jing

    2016-01-01

    We investigate the nanosecond pulse noise-hidden image reconstruction and visualization using stochastic resonance implemented by modulation instability. In particular, this dynamical stochastic resonance holds with coupling between the pulse incoherent noise and pulse coherent signal, and provides a substantial enhancement of the signal-to-noise ratio and cross-correlation. This means that the pulse noise-hidden image can be effectively reconstructed with high visibility and fidelity via stochastic resonance at appropriate system parameters. Such a simple and convenient method has potential applications in image processing under noisy environment. PMID:27824152

  10. Vestibular Hyperacusis

    MedlinePlus

    ... Vestibular Disorders Diagnosis & Treatment Types of Vestibular Disorders Acoustic Neuroma/Vestibular Schwannoma Age-related dizziness and imbalance ... significant information. Cochlear hyperacusis can be treated with acoustic therapies such as tinnitus retraining therapy (TRT). The ...

  11. On square-wave-driven stochastic resonance for energy harvesting in a bistable system

    SciTech Connect

    Su, Dongxu; Zheng, Rencheng; Nakano, Kimihiko; Cartmell, Matthew P

    2014-11-15

    Stochastic resonance is a physical phenomenon through which the throughput of energy within an oscillator excited by a stochastic source can be boosted by adding a small modulating excitation. This study investigates the feasibility of implementing square-wave-driven stochastic resonance to enhance energy harvesting. The motivating hypothesis was that such stochastic resonance can be efficiently realized in a bistable mechanism. However, the condition for the occurrence of stochastic resonance is conventionally defined by the Kramers rate. This definition is inadequate because of the necessity and difficulty in estimating white noise density. A bistable mechanism has been designed using an explicit analytical model which implies a new approach for achieving stochastic resonance in the paper. Experimental tests confirm that the addition of a small-scale force to the bistable system excited by a random signal apparently leads to a corresponding amplification of the response that we now term square-wave-driven stochastic resonance. The study therefore indicates that this approach may be a promising way to improve the performance of an energy harvester under certain forms of random excitation.

  12. A stochastic resonator is able to greatly improve signal-to-noise ratio

    NASA Astrophysics Data System (ADS)

    Loerincz, K.; Gingl, Z.; Kiss, L. B.

    1996-02-01

    After a decade of doubts, for the first time in the history of stochastic resonance (SR), we demonstrate that a simple stochastic resonator does greatly improve the signal-to-noise ratio (SNR) of a periodic signal with additive Gaussian noise. The particular stochastic resonator is a level-crossing detector (LCD) driven by the sum of a periodic spike train signal and a band-limited Gaussian white noise. To reach the improvement of the SNR, the stochastic resonator has to work in the strongly nonlinear response limit and the noise has to have a high cut-off frequency compared to the reciprocal duration of the spikes. We demonstrate by analog and computer simulations that the SNR gain goes beyond four orders of magnitude at practical conditions. These findings get a particular importance due the fact that simplest neurone models behave very similarly to our arrangement, so the results might have direct applications in neural systems.

  13. Temporal encoding in auditory evoked neuromagnetic fields: stochastic resonance.

    PubMed

    Stufflebeam, S M; Poeppel, D; Roberts, T P

    2000-12-18

    Recent investigations have demonstrated that temporal patterns of sensory neural activity detected by magnetoencephalography (MEG) reflect features of the stimulus. In this study, neuromagnetic activity was investigated using an event detection algorithm based on the correlation coefficient. The results of the technique are compared with widely used methods of analysis in two experimental conditions and are shown to identify features in the single-trial MEG response that are not apparent in the response obtained by averaging across repeated trials. As an example of the technique, the physiologic jitter in latency associated with the M100 of auditory evoked fields was reproducibly measured. Specifically, higher intensity sounds were associated with an increased reliability. The technique was also applied to the noise-enhanced evoked auditory response, producing an objective demonstration of a cortical manifestation of the phenomenon of stochastic resonance-the paradoxical enhancement in the measurement of the signal-to-noise ratio (SNR) induced by optimal addition of noise to system input.

  14. COMMUNICATION: Stochastic resonance and the evolution of Daphnia foraging strategy

    NASA Astrophysics Data System (ADS)

    Dees, Nathan D.; Bahar, Sonya; Moss, Frank

    2008-12-01

    Search strategies are currently of great interest, with reports on foraging ranging from albatrosses and spider monkeys to microzooplankton. Here, we investigate the role of noise in optimizing search strategies. We focus on the zooplankton Daphnia, which move in successive sequences consisting of a hop, a pause and a turn through an angle. Recent experiments have shown that their turning angle distributions (TADs) and underlying noise intensities are similar across species and age groups, suggesting an evolutionary origin of this internal noise. We explore this hypothesis further with a digital simulation (EVO) based solely on the three central Darwinian themes: inheritability, variability and survivability. Separate simulations utilizing stochastic resonance (SR) indicate that foraging success, and hence fitness, is maximized at an optimum TAD noise intensity, which is represented by the distribution's characteristic width, σ. In both the EVO and SR simulations, foraging success is the criterion, and the results are the predicted characteristic widths of the TADs that maximize success. Our results are twofold: (1) the evolving characteristic widths achieve stasis after many generations; (2) as a hop length parameter is changed, variations in the evolved widths generated by EVO parallel those predicted by SR. These findings provide support for the hypotheses that (1) σ is an evolved quantity and that (2) SR plays a role in evolution.

  15. Stochastic resonance-enhanced laser-based particle detector.

    PubMed

    Dutta, A; Werner, C

    2009-01-01

    This paper presents a Laser-based particle detector whose response was enhanced by modulating the Laser diode with a white-noise generator. A Laser sheet was generated to cast a shadow of the object on a 200 dots per inch, 512 x 1 pixels linear sensor array. The Laser diode was modulated with a white-noise generator to achieve stochastic resonance. The white-noise generator essentially amplified the wide-bandwidth (several hundred MHz) noise produced by a reverse-biased zener diode operating in junction-breakdown mode. The gain in the amplifier in the white-noise generator was set such that the Receiver Operating Characteristics plot provided the best discriminability. A monofiber 40 AWG (approximately 80 microm) wire was detected with approximately 88% True Positive rate and approximately 19% False Positive rate in presence of white-noise modulation and with approximately 71% True Positive rate and approximately 15% False Positive rate in absence of white-noise modulation.

  16. Stochastic Resonance in Time-to-Contact Judgments

    NASA Astrophysics Data System (ADS)

    Ranjit, Manish; Gazula, Harshvardhan; Hsiang, Simon M.; Delucia, Patricia R.

    2015-04-01

    Stochastic resonance (SR) is a counterintuitive phenomenon in which additive noise enhances performance of a nonlinear system. Previous studies demonstrated SR effect on human tactile sensitivity by adding noise of same modality and cross modality. Similarly, enhancement of human hearing through additive noise has been studied. In this study, we investigate the effect of noise in visual perception, specifically time-to-contact (TTC) judgments. This study explores four research questions: (1) Does noise help in TTC judgments? (2) How does noise affect speed and accuracy of TTC judgments? (3) Does cross modal noise help in TTC judgments? (4) How does cross modal noise affect speed and accuracy of TTC judgments? Through simulation, we show that noise in optical cue can enhance weak signals. We also demonstrate that noise can improve speed of TTC judgments at the expense of accuracy. Similarly, we demonstrate SR by adding noise of cross modality. These findings provide plausible hypotheses regarding how much noise should be added to enhance TTC judgments.

  17. Stochastic Resonance in crayfish hydrodynamic receptors stimulated with external noise

    NASA Astrophysics Data System (ADS)

    Douglass, J. K.; Wilkens, L. A.; Pantazelou, E.; Moss, F.

    1993-08-01

    Stochastic Resonance (SR) is a statistical process occurring only in nonlinear dynamical systems whereby a subthreshold coherent stimulus or signal can be enhanced by noise. The signal alone is too weak to cause a state change of the system. State changes are the carriers of information through the system. In the presence of random noise, however, the system can change state, more-or-less randomly, but with some degree of coherence with the signal. A measure of this coherence at the output shows a maximum at an optimal value of the noise intensity as the signature of SR. SR is the object of recent and continued experimental and theoretical research in statistical physics. While SR has been demonstrated in a variety of physical systems, it has not yet been discovered in any naturally occurring system. This paper was stimulated by the idea that the sensory nervous system might be an appropriate setting for a search for naturally occurring SR. The detection of weak stimuli, often in the presence of noise, is, after all, the first business of the sensory system. Moreover, the system is evolved, which admits the possibility that the process of natural selection might have resulted in an optimization with respect to the (inevitable) noise. This paper describes an experiment designed to observe SR in the mechanoreceptor cells of the crayfish Procambarus clarkii, shown on the left in Fig. 1, using external noise plus a weak coherent signal as the stimulus.

  18. 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.

  19. Effects of time delay on the stochastic resonance in small-world neuronal networks.

    PubMed

    Yu, Haitao; Wang, Jiang; Du, Jiwei; Deng, Bin; Wei, Xile; Liu, Chen

    2013-03-01

    The effects of time delay on stochastic resonance in small-world neuronal networks are investigated. Without delay, an intermediate intensity of additive noise is able to optimize the temporal response of the neural system to the subthreshold periodic signal imposed on all neurons constituting the network. The time delay in the coupling process can either enhance or destroy stochastic resonance of neuronal activity in the small-world network. In particular, appropriately tuned delays can induce multiple stochastic resonances, which appear intermittently at integer multiples of the oscillation period of weak external forcing. It is found that the delay-induced multiple stochastic resonances are most efficient when the forcing frequency is close to the global-resonance frequency of each individual neuron. Furthermore, the impact of time delay on stochastic resonance is largely independent of the small-world topology, except for resonance peaks. Considering that information transmission delays are inevitable in intra- and inter-neuronal communication, the presented results could have important implications for the weak signal detection and information propagation in neural systems.

  20. Stochastic resonance on a global atmospheric circulation model

    NASA Astrophysics Data System (ADS)

    Perez-Munuzuri, V.; Deza, R.; Fraedrich, K.; Kirk, E.; Lunkeit, F.

    2003-04-01

    Seeking for alternative sources of the observed climatic variability, and in the spirit of both classic (Nicolis, 1982; Benzi et al., 1982) and recent work (Ganopolski and Rahmstorg, 2002; Vélez-Belch&{acute;i} et al., 2001), we have added a space-independent, Gaussian and uncorrelated stochastic perturbation with amplitude eta, to the temperature equation of a simplified atmospheric global circulation model, the so-called PUMA (Portable University Model of the Atmosphere) (Frisius et al., 1998; Pérez-Muñuzuri et al., 2003). In the latter model, diabatic processes are parameterized by a Newtonian cooling term with typical timescale τ_c, whose reference temperature profile T_R(λ,μ,σ;t) (representing the ``equilibrium'' profile induced by solar heating) is given by T_R=overline{T}_R(λ,μ,σ)+ hat{T}_R \\cos[(2pi/Tac)t+Pac]. We show that the time averages of several forecasting magnitudes (like temperature and horizontal vorticity) at a point on the 300 hPa surface, undergo a non-monotonic behavior with regard to eta. Moreover, the normalized variance R=sqrt{-^2}/ of the interval t_p between the passage at the point of cyclonic and anticyclonic circulation regions exhibits an ``anticoherence resonance'' effect, thus maximizing climatic variability for some intermediate value of eta. A theoretical explanation is advanced in terms of activated processes with competing time scales. begin{itemize} C. Nicolis, Tellus 34, 1 (1982); Benzi et al., Tellus 34, 10 (1982). A. Ganopolski and S. Rahmstorg, Phys. Rev. Lett. 88, 038501 (2002); P. Vélez-Belch&{acute;i} et al., Geophys. Res. Lett. 28, 2053 (2001). T. Frisius, F. Lunkeit, K. Fraedrich and I.N. James. Q.J.R. Meteorol. Soc. 124, 1019 (1998); V. Pérez-Muñuzuri et al. Nonlin. Proc. Geophys. (submitted) (2003).

  1. Vestibular neuritis.

    PubMed

    Jeong, Seong-Hae; Kim, Hyo-Jung; Kim, Ji-Soo

    2013-07-01

    Vestibular neuritis is the most common cause of acute spontaneous vertigo. Vestibular neuritis is ascribed to acute unilateral loss of vestibular function, probably due to reactivation of herpes simplex virus in the vestibular ganglia. The diagnostic hallmarks of vestibular neuritis are spontaneous horizontal-torsional nystagmus beating away from the lesion side, abnormal head impulse test for the involved semicircular canals, ipsilesional caloric paresis, decreased responses of vestibular-evoked myogenic potentials during stimulation of the affected ear, and unsteadiness with a falling tendency toward the lesion side. Vestibular neuritis preferentially involves the superior vestibular labyrinth and its afferents. Accordingly, the function of the posterior semicircular canal and saccule, which constitute the inferior vestibular labyrinth, is mostly spared in vestibular neuritis. However, because the rare subtype of inferior vestibular neuritis lacks the typical features of vestibular neuritis, it may be misdiagnosed as a central vestibular disorder. Even in the patient with the typical pattern of spontaneous nystagmus observed in vestibular neuritis, brain imaging is indicated when the patient has unprecedented headache, negative head impulse test, severe unsteadiness, or no recovery within 1 to 2 days. Symptomatic medication is indicated only during the acute phase to relieve the vertigo and nausea/vomiting. Vestibular rehabilitation hastens the recovery. The efficacy of topical and systemic steroids requires further validation.

  2. Two Stochastic Resonances Induced by Two Different Multiplicative Telegraphic Noises for an Electric System

    NASA Astrophysics Data System (ADS)

    Li, Jing-Hui

    2008-11-01

    In this paper, an electric system with two dichotomous resistors is investigated. It is shown that this system can display two stochastic resonances, which are the amplitude of the periodic response as the functions of the two dichotomous resistors strengthes respectively. In the limits of Gaussian white noise and shot white noise (i.e., the two noises are both Gaussian white noise or shot white noise), no phenomena of resonance appear. By further study, we find that when the system is with three or more multiplicative telegraphic noises, there are three or more stochastic resonances.

  3. Stochastic Resonance Modulates Neural Synchronization within and between Cortical Sources

    PubMed Central

    Ward, Lawrence M.; MacLean, Shannon E.; Kirschner, Aaron

    2010-01-01

    Neural synchronization is a mechanism whereby functionally specific brain regions establish transient networks for perception, cognition, and action. Direct addition of weak noise (fast random fluctuations) to various neural systems enhances synchronization through the mechanism of stochastic resonance (SR). Moreover, SR also occurs in human perception, cognition, and action. Perception, cognition, and action are closely correlated with, and may depend upon, synchronized oscillations within specialized brain networks. We tested the hypothesis that SR-mediated neural synchronization occurs within and between functionally relevant brain areas and thus could be responsible for behavioral SR. We measured the 40-Hz transient response of the human auditory cortex to brief pure tones. This response arises when the ongoing, random-phase, 40-Hz activity of a group of tuned neurons in the auditory cortex becomes synchronized in response to the onset of an above-threshold sound at its “preferred” frequency. We presented a stream of near-threshold standard sounds in various levels of added broadband noise and measured subjects' 40-Hz response to the standards in a deviant-detection paradigm using high-density EEG. We used independent component analysis and dipole fitting to locate neural sources of the 40-Hz response in bilateral auditory cortex, left posterior cingulate cortex and left superior frontal gyrus. We found that added noise enhanced the 40-Hz response in all these areas. Moreover, added noise also increased the synchronization between these regions in alpha and gamma frequency bands both during and after the 40-Hz response. Our results demonstrate neural SR in several functionally specific brain regions, including areas not traditionally thought to contribute to the auditory 40-Hz transient response. In addition, we demonstrated SR in the synchronization between these brain regions. Thus, both intra- and inter-regional synchronization of neural activity are

  4. Acute effects of stochastic resonance whole body vibration

    PubMed Central

    Elfering, Achim; Zahno, Jasmine; Taeymans, Jan; Blasimann, Angela; Radlinger, Lorenz

    2013-01-01

    AIM: To investigate the acute effects of stochastic resonance whole body vibration (SR-WBV) training to identify possible explanations for preventive effects against musculoskeletal disorders. METHODS: Twenty-three healthy, female students participated in this quasi-experimental pilot study. Acute physiological and psychological effects of SR-WBV training were examined using electromyography of descending trapezius (TD) muscle, heart rate variability (HRV), different skin parameters (temperature, redness and blood flow) and self-report questionnaires. All subjects conducted a sham SR-WBV training at a low intensity (2 Hz with noise level 0) and a verum SR-WBV training at a higher intensity (6 Hz with noise level 4). They were tested before, during and after the training. Conclusions were drawn on the basis of analysis of variance. RESULTS: Twenty-three healthy, female students participated in this study (age = 22.4 ± 2.1 years; body mass index = 21.6 ± 2.2 kg/m2). Muscular activity of the TD and energy expenditure rose during verum SR-WBV compared to baseline and sham SR-WBV (all P < 0.05). Muscular relaxation after verum SR-WBV was higher than at baseline and after sham SR-WBV (all P < 0.05). During verum SR-WBV the levels of HRV were similar to those observed during sham SR-WBV. The same applies for most of the skin characteristics, while microcirculation of the skin of the middle back was higher during verum compared to sham SR-WBV (P < 0.001). Skin redness showed significant changes over the three measurement points only in the middle back area (P = 0.022). There was a significant rise from baseline to verum SR-WBV (0.86 ± 0.25 perfusion units; P = 0.008). The self-reported chronic pain grade indicators of pain, stiffness, well-being, and muscle relaxation showed a mixed pattern across conditions. Muscle and joint stiffness (P = 0.018) and muscular relaxation did significantly change from baseline to different conditions of SR-WBV (P < 0.001). Moreover

  5. Stochastic Resonance Improves Broadband Encoding in the Cricket Cercal System.

    NASA Astrophysics Data System (ADS)

    Levin, Jacob

    1996-03-01

    In any physical or biological system a certain amount of environmental noise is unavoidable, and the information therein irrelevant to the organism. Traditionally in signal analysis noise is considered detrimental to the process of signal encoding, and merely a necessary evil to be avoided. It has been observed recently, however, that in some nonlinear systems power from random input noise actually improves the output signal-to-noise ratio (SNR) over a limited operating range, particularly near threshold. This effect is known as stochastic resonance (SR). By taking advantage of SR during the neural encoding process, a cell can optimize its information flow properties. Previous experimental work in SR has investigated only the coding of sinusoidal signals embedded in a broadband white noise background. In this work we demonstrate SR for not only the sine wave case, but also for extended bandwidth stimuli in the presence of white noise, and for cases in which the signal and white noise background frequency spectra are completely non-overlapping. We have investigated the effects of noise on information transfer in the cricket cercal system, a mechanosensory system sensitive to small near-field air particle disturbances, by presenting known wind stimuli to the cricket through audio speakers in a controlled environment along with varying levels of uncorrelated white noise background air current. Spike trains from the second layer of neuronal processing, the primary sensory interneurons, were recorded with intracellular electrodes with the signal and noise presented along the cell's preferred direction. Through the statistical techniques of Shannon's information theory we quantified the amount of information contained in the elicited spike trains about the signal in the various noise environments, as well as the SNR and other measures of the encoding process. An enhancement of output SNR was observed over the entire frequency operating range of the neurons, for almost an

  6. What is stochastic resonance? Definitions, misconceptions, debates, and its relevance to biology.

    PubMed

    McDonnell, Mark D; Abbott, Derek

    2009-05-01

    Stochastic resonance is said to be observed when increases in levels of unpredictable fluctuations--e.g., random noise--cause an increase in a metric of the quality of signal transmission or detection performance, rather than a decrease. This counterintuitive effect relies on system nonlinearities and on some parameter ranges being "suboptimal". Stochastic resonance has been observed, quantified, and described in a plethora of physical and biological systems, including neurons. Being a topic of widespread multidisciplinary interest, the definition of stochastic resonance has evolved significantly over the last decade or so, leading to a number of debates, misunderstandings, and controversies. Perhaps the most important debate is whether the brain has evolved to utilize random noise in vivo, as part of the "neural code". Surprisingly, this debate has been for the most part ignored by neuroscientists, despite much indirect evidence of a positive role for noise in the brain. We explore some of the reasons for this and argue why it would be more surprising if the brain did not exploit randomness provided by noise--via stochastic resonance or otherwise--than if it did. We also challenge neuroscientists and biologists, both computational and experimental, to embrace a very broad definition of stochastic resonance in terms of signal-processing "noise benefits", and to devise experiments aimed at verifying that random variability can play a functional role in the brain, nervous system, or other areas of biology.

  7. What Is Stochastic Resonance? Definitions, Misconceptions, Debates, and Its Relevance to Biology

    PubMed Central

    McDonnell, Mark D.; Abbott, Derek

    2009-01-01

    Stochastic resonance is said to be observed when increases in levels of unpredictable fluctuations—e.g., random noise—cause an increase in a metric of the quality of signal transmission or detection performance, rather than a decrease. This counterintuitive effect relies on system nonlinearities and on some parameter ranges being “suboptimal”. Stochastic resonance has been observed, quantified, and described in a plethora of physical and biological systems, including neurons. Being a topic of widespread multidisciplinary interest, the definition of stochastic resonance has evolved significantly over the last decade or so, leading to a number of debates, misunderstandings, and controversies. Perhaps the most important debate is whether the brain has evolved to utilize random noise in vivo, as part of the “neural code”. Surprisingly, this debate has been for the most part ignored by neuroscientists, despite much indirect evidence of a positive role for noise in the brain. We explore some of the reasons for this and argue why it would be more surprising if the brain did not exploit randomness provided by noise—via stochastic resonance or otherwise—than if it did. We also challenge neuroscientists and biologists, both computational and experimental, to embrace a very broad definition of stochastic resonance in terms of signal-processing “noise benefits”, and to devise experiments aimed at verifying that random variability can play a functional role in the brain, nervous system, or other areas of biology. PMID:19562010

  8. A review of methods for identifying stochastic resonance in simulations of single neuron models.

    PubMed

    McDonnell, Mark D; Iannella, Nicolangelo; To, Minh-Son; Tuckwell, Henry C; Jost, Jürgen; Gutkin, Boris S; Ward, Lawrence M

    2015-01-01

    Stochastic resonance (SR) is said to be observed when the presence of noise in a nonlinear system enables an output signal from the system to better represent some feature of an input signal than it does in the absence of noise. The effect has been observed in models of individual neurons, and in experiments performed on real neural systems. Despite the ubiquity of biophysical sources of stochastic noise in the nervous system, however, it has not yet been established whether neuronal computation mechanisms involved in performance of specific functions such as perception or learning might exploit such noise as an integral component, such that removal of the noise would diminish performance of these functions. In this paper we revisit the methods used to demonstrate stochastic resonance in models of single neurons. This includes a previously unreported observation in a multicompartmental model of a CA1-pyramidal cell. We also discuss, as a contrast to these classical studies, a form of 'stochastic facilitation', known as inverse stochastic resonance. We draw on the reviewed examples to argue why new approaches to studying 'stochastic facilitation' in neural systems need to be developed.

  9. Stochastic charging of dust grains in planetary rings: Diffusion rates and their effects on Lorentz resonances

    NASA Technical Reports Server (NTRS)

    Schaffer, L.; Burns, J. A.

    1995-01-01

    Dust grains in planetary rings acquire stochastically fluctuating electric charges as they orbit through any corotating magnetospheric plasma. Here we investigate the nature of this stochastic charging and calculate its effect on the Lorentz resonance (LR). First we model grain charging as a Markov process, where the transition probabilities are identified as the ensemble-averaged charging fluxes due to plasma pickup and photoemission. We determine the distribution function P(t;N), giving the probability that a grain has N excess charges at time t. The autocorrelation function tau(sub q) for the strochastic charge process can be approximated by a Fokker-Planck treatment of the evolution equations for P(t; N). We calculate the mean square response to the stochastic fluctuations in the Lorentz force. We find that transport in phase space is very small compared to the resonant increase in amplitudes due to the mean charge, over the timescale that the oscillator is resonantly pumped up. Therefore the stochastic charge variations cannot break the resonant interaction; locally, the Lorentz resonance is a robust mechanism for the shaping of etheral dust ring systems. Slightly stronger bounds on plasma parameters are required when we consider the longer transit times between Lorentz resonances.

  10. Stochastic Resonance in a Simple Threshold Sensor System with Alpha Stable Noise

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi-Rui; Kang, Yan-Mei; Xie, Yong

    2014-05-01

    We investigate the effect of alpha stable noise on stochastic resonance in a single-threshold sensor system by analytic deduction and stochastic simulation. It is shown that stochastic resonance occurs in the threshold system in alpha stable noise environment, but the resonant effect becomes weakened as the alpha stable index decreases or the skewness parameter of alpha stable distribution increases. In particular, for Cauchy noise a nonlinear relation among the optimal noise deviation parameter, the signal amplitude and the threshold is analytically obtained and illustrated by using the extreme value condition for the output signal-to-noise ratio. The results presented in this communication should have application in signal detection and image restoration in the non-Gaussian noisy environment.

  11. Effect of mechanical tactile noise on amplitude of visual evoked potentials: multisensory stochastic resonance

    PubMed Central

    Huidobro, Nayeli; Silva, Mayte; Flores, Amira; Trenado, Carlos; Quintanar, Luis; Arias-Carrión, Oscar; Kristeva, Rumyana

    2015-01-01

    The present investigation documents the electrophysiological occurrence of multisensory stochastic resonance in the human visual pathway elicited by tactile noise. We define multisensory stochastic resonance of brain evoked potentials as the phenomenon in which an intermediate level of input noise of one sensory modality enhances the brain evoked response of another sensory modality. Here we examined this phenomenon in visual evoked potentials (VEPs) modulated by the addition of tactile noise. Specifically, we examined whether a particular level of mechanical Gaussian noise applied to the index finger can improve the amplitude of the VEP. We compared the amplitude of the positive P100 VEP component between zero noise (ZN), optimal noise (ON), and high mechanical noise (HN). The data disclosed an inverted U-like graph for all the subjects, thus demonstrating the occurrence of a multisensory stochastic resonance in the P100 VEP. PMID:26156387

  12. Effect of mechanical tactile noise on amplitude of visual evoked potentials: multisensory stochastic resonance.

    PubMed

    Méndez-Balbuena, Ignacio; Huidobro, Nayeli; Silva, Mayte; Flores, Amira; Trenado, Carlos; Quintanar, Luis; Arias-Carrión, Oscar; Kristeva, Rumyana; Manjarrez, Elias

    2015-10-01

    The present investigation documents the electrophysiological occurrence of multisensory stochastic resonance in the human visual pathway elicited by tactile noise. We define multisensory stochastic resonance of brain evoked potentials as the phenomenon in which an intermediate level of input noise of one sensory modality enhances the brain evoked response of another sensory modality. Here we examined this phenomenon in visual evoked potentials (VEPs) modulated by the addition of tactile noise. Specifically, we examined whether a particular level of mechanical Gaussian noise applied to the index finger can improve the amplitude of the VEP. We compared the amplitude of the positive P100 VEP component between zero noise (ZN), optimal noise (ON), and high mechanical noise (HN). The data disclosed an inverted U-like graph for all the subjects, thus demonstrating the occurrence of a multisensory stochastic resonance in the P100 VEP.

  13. Possible breakthrough: Significant improvement of signal to noise ratio by stochastic resonance

    NASA Astrophysics Data System (ADS)

    Kiss, L. B.

    1996-06-01

    The simplest stochastic resonator is used, a level crossing detector (LCD), to investigate key properties of stochastic resonance (SR). It is pointed out that successful signal processing and biological applications of SR require to work in the large signal limit (nonlinear transfer limit) which requires a completely new approach: wide band input signal and a new, generalised definition of output noise. The new way of approach is illustrated by a new arrangement. The arrangement employs a special LCD, white input noise and a special, large, subthreshold wide band signal. First time in the history of SR (for a wide band input noise), the signal to noise ratio becomes much higher at the output of a stochastic resonator than at its input. In that way, SR is proven to have a potential to improve signal transfer. Note, that the new arrangement seems to have resemblance to neurone models, therefore, it has a potential also for biological applications.

  14. Stochastic Parameter Resonance of Road-Vehicle Systems and Related Bifurcation Problems

    NASA Astrophysics Data System (ADS)

    Wedig, Walter V.

    The paper investigates stochastic dynamics of road-vehicle systems and related bifurcation problems. The ride on rough roads generates vertical car vibrations whose root-mean-squares are resonant for critical car speeds and vanish when the car velocity is increasing, infinitely. These investigations are extended to wheel suspensions with progressive spring characteristics. For weak but still positive damping, the car vibrations become unstable when the velocity reaches the parameter resonance near twice the critical speed bifurcating into stochastic chaos of larger non-stationary car vibrations.

  15. Harvesting wind energy to detect weak signals using mechanical stochastic resonance

    NASA Astrophysics Data System (ADS)

    Breen, Barbara J.; Rix, Jillian G.; Ross, Samuel J.; Yu, Yue; Lindner, John F.; Mathewson, Nathan; Wainwright, Elliot R.; Wilson, Ian

    2016-12-01

    Wind is free and ubiquitous and can be harnessed in multiple ways. We demonstrate mechanical stochastic resonance in a tabletop experiment in which wind energy is harvested to amplify weak periodic signals detected via the movement of an inverted pendulum. Unlike earlier mechanical stochastic resonance experiments, where noise was added via electrically driven vibrations, our broad-spectrum noise source is a single flapping flag. The regime of the experiment is readily accessible, with wind speeds ˜20 m/s and signal frequencies ˜1 Hz. We readily obtain signal-to-noise ratios on the order of 10 dB.

  16. Harvesting wind energy to detect weak signals using mechanical stochastic resonance.

    PubMed

    Breen, Barbara J; Rix, Jillian G; Ross, Samuel J; Yu, Yue; Lindner, John F; Mathewson, Nathan; Wainwright, Elliot R; Wilson, Ian

    2016-12-01

    Wind is free and ubiquitous and can be harnessed in multiple ways. We demonstrate mechanical stochastic resonance in a tabletop experiment in which wind energy is harvested to amplify weak periodic signals detected via the movement of an inverted pendulum. Unlike earlier mechanical stochastic resonance experiments, where noise was added via electrically driven vibrations, our broad-spectrum noise source is a single flapping flag. The regime of the experiment is readily accessible, with wind speeds ∼20 m/s and signal frequencies ∼1 Hz. We readily obtain signal-to-noise ratios on the order of 10 dB.

  17. MODELING OF COUPLED EDGE STOCHASTIC AND CORE RESONANT MAGNETIC FIELD EFFECTS IN DIVERTED TOKAMAKS

    SciTech Connect

    EVANS, T.E.; MOYER, R.A.

    2002-06-01

    Attaining the highest performance in poloidally diverted tokamaks requires resonant magnetic perturbation coils to avoid core instabilities (locked, resistive wall and neoclassical tearing modes). These coils also perturb the pedestal and edge region, causing varying degrees of stochasticity with remnant islands. The effects of the DIII-D locked mode control coil on the edge and core of Ohmic plasmas are modeled with the field line integration code TRIP3D and compared with experimental measurements. Without detailed profile analysis and field line integration, it is difficult to establish whether a given response is due to a ''core mode'' or an ''edge stochastic boundary.'' In diverted Ohmic plasmas, the boundary stochastic layer displays many characteristics associated with such layers in non-diverted tokamaks. Comparison with stochastic boundary results from non-diverted tokamaks indicates that a significant difference in diverted tokamaks is a ''focusing'' of the magnetic field line loss into the vicinity of the divertor.

  18. Fluctuations induced extinction and stochastic resonance effect in a model of tumor growth with periodic treatment

    NASA Astrophysics Data System (ADS)

    Li, Dongxi; Xu, Wei; Guo, Yongfeng; Xu, Yong

    2011-01-01

    We investigate a stochastic model of tumor growth derived from the catalytic Michaelis-Menten reaction with positional and environmental fluctuations under subthreshold periodic treatment. Firstly, the influences of environmental fluctuations on the treatable stage are analyzed numerically. Applying the standard theory of stochastic resonance derived from the two-state approach, we derive the signal-to-noise ratio (SNR) analytically, which is used to measure the stochastic resonance phenomenon. It is found that the weak environmental fluctuations could induce the extinction of tumor cells in the subthreshold periodic treatment. The positional stability is better in favor of the treatment of the tumor cells. Besides, the appropriate and feasible treatment intensity and the treatment cycle should be highlighted considered in the treatment of tumor cells.

  19. Stochastic resonance in a fractional oscillator driven by multiplicative quadratic noise

    NASA Astrophysics Data System (ADS)

    Ren, Ruibin; Luo, Maokang; Deng, Ke

    2017-02-01

    Stochastic resonance of a fractional oscillator subject to an external periodic field as well as to multiplicative and additive noise is investigated. The fluctuations of the eigenfrequency are modeled as the quadratic function of the trichotomous noise. Applying the moment equation method and Shapiro–Loginov formula, we obtain the exact expression of the complex susceptibility and related stability criteria. Theoretical analysis and numerical simulations indicate that the spectral amplification (SPA) depends non-monotonicly both on the external driving frequency and the parameters of the quadratic noise. In addition, the investigations into fractional stochastic systems have suggested that both the noise parameters and the memory effect can induce the phenomenon of stochastic multi-resonance (SMR), which is previously reported and believed to be absent in the case of the multiplicative noise with only a linear term.

  20. Transition paths to stochastic oscillations of a self-excited oscillator with a ferrite resonator

    SciTech Connect

    Aranson, I.S.; Pavlov, D.A.

    1986-01-01

    It is demonstrated experimentally that the transition to stochastic oscillations in a self-excited oscillator with ferrite resonator occurs through the complexification of the structure of self-modulation. All basic types of bifurcations are recorded: doubling, intermittency, hard onset of chaos, and critical behavior of strange attractors. Tripling of the self-modulation period was observed for special values of the parameters.

  1. Broadband neural encoding in the cricket cereal sensory system enhanced by stochastic resonance

    NASA Astrophysics Data System (ADS)

    Levin, Jacob E.; Miller, John P.

    1996-03-01

    SENSORY systems are often required to detect a small amplitude signal embedded in broadband background noise. Traditionally, ambient noise is regarded as detrimental to encoding accuracy. Recently, however, a phenomenon known as stochastic resonance has been described in which, for systems with a nonlinear threshold, increasing the input noise level can actually improve the output signal-to-noise ratio over a limited range of signal and noise strengths. Previous theoretical and experimental studies of stochastic resonance in physical1-7and biological6-10 systems have dealt exclusively with single-frequency sine stimuli embedded in a broadband noise background. In the past year it has been shown in a theoretical and modelling study that stochastic resonance can be observed with broadband signals11,12. Here we demonstrate that broadband stochastic resonance is manifest in the peripheral layers of neural processing in a simple sensory system, and that it plays a role over a wide range of biologically relevant stimulus parameters. Further, we quantify the functional significance of the phenomenon within the context of signal processing, using information theory.

  2. Investigations of stochastic resonance in two-terminal device with vanadium dioxide film

    SciTech Connect

    Aliev, V. Sh. Bortnikov, S. G.; Badmaeva, I. A.

    2014-05-28

    The results of stochastic resonance investigation in a nonlinear system, consisting of a microstructure with a polycrystalline vanadium dioxide (VO{sub 2}) film grown on sapphire and resistor in series are reported. Nonlinearity of the system was provided due to insulator-metal phase transition in VO{sub 2}. In the stochastic resonance regime at 100 Hz signal frequency, the transition coefficient of signal-to-noise ratio reached 87 in contrast to 250 for microstructures with VO{sub 2} films grown on silica in our previous investigations. The measured characteristics of microstructures with VO{sub 2} films grown on silica and sapphire substrates were found to be qualitatively similar. For both substrates, a stochastic resonance was observed at threshold switching voltage from insulating to metallic state of VO{sub 2}. For sapphire substrate the output signal-to-noise ratio rose at higher signal frequencies. The stochastic resonance phenomenon in VO{sub 2} films is explained in terms of the monostable damped oscillator model.

  3. Stochastic resonance is a method to improve the biosynthetic response of chondrocytes to mechanical stimulation.

    PubMed

    Weber, Joanna F; Waldman, Stephen D

    2016-02-01

    Cellular mechanosensitivity is an important factor during the mechanical stimulation of tissue engineered cartilage. While the application of mechanical stimuli improves tissue growth and properties, chondrocytes also rapidly desensitize under prolonged loading thereby limiting its effectiveness. One potential method to mitigate load-induced desensitization is by superimposing noise on the loading waveforms ("stochastic resonance"). Thus, the purpose of this study was to investigate the effects of stochastic resonance on chondrocyte matrix metabolism. Chondrocyte-seeded agarose gels were subjected to dynamic compressive loading, with or without, superimposed vibrations of different amplitudes and frequency bandwidths. Changes in matrix biosynthesis were determined by radioisotope incorporation and subsequent effects on intracellular calcium signaling were evaluated by confocal microscopy. Although dependent on the duration of loading, superimposed vibrations improved cellular sensitivity to mechanical loading by further increasing matrix synthesis between 20-60%. Stochastic resonance also appeared to limit load-induced desensitization by maintaining sensitivity under desensitized loading conditions. While superimposed vibrations had little effect on the magnitude of intracellular calcium signaling, recovery of mechanosensitivity after stimulation was achieved at a faster rate suggesting that less time may be required between successive loading applications. Thus, stochastic resonance appears to be a valuable tool during the mechanical stimulation of cartilage constructs, even when suboptimal stimulation conditions are used.

  4. Effectiveness Testing of a Piezoelectric Energy Harvester for an Automobile Wheel Using Stochastic Resonance

    PubMed Central

    Zhang, Yunshun; Zheng, Rencheng; Shimono, Keisuke; Kaizuka, Tsutomu; Nakano, Kimihiko

    2016-01-01

    The collection of clean power from ambient vibrations is considered a promising method for energy harvesting. For the case of wheel rotation, the present study investigates the effectiveness of a piezoelectric energy harvester, with the application of stochastic resonance to optimize the efficiency of energy harvesting. It is hypothesized that when the wheel rotates at variable speeds, the energy harvester is subjected to on-road noise as ambient excitations and a tangentially acting gravity force as a periodic modulation force, which can stimulate stochastic resonance. The energy harvester was miniaturized with a bistable cantilever structure, and the on-road noise was measured for the implementation of a vibrator in an experimental setting. A validation experiment revealed that the harvesting system was optimized to capture power that was approximately 12 times that captured under only on-road noise excitation and 50 times that captured under only the periodic gravity force. Moreover, the investigation of up-sweep excitations with increasing rotational frequency confirmed that stochastic resonance is effective in optimizing the performance of the energy harvester, with a certain bandwidth of vehicle speeds. An actual-vehicle experiment validates that the prototype harvester using stochastic resonance is capable of improving power generation performance for practical tire application. PMID:27763522

  5. Effectiveness Testing of a Piezoelectric Energy Harvester for an Automobile Wheel Using Stochastic Resonance.

    PubMed

    Zhang, Yunshun; Zheng, Rencheng; Shimono, Keisuke; Kaizuka, Tsutomu; Nakano, Kimihiko

    2016-10-17

    The collection of clean power from ambient vibrations is considered a promising method for energy harvesting. For the case of wheel rotation, the present study investigates the effectiveness of a piezoelectric energy harvester, with the application of stochastic resonance to optimize the efficiency of energy harvesting. It is hypothesized that when the wheel rotates at variable speeds, the energy harvester is subjected to on-road noise as ambient excitations and a tangentially acting gravity force as a periodic modulation force, which can stimulate stochastic resonance. The energy harvester was miniaturized with a bistable cantilever structure, and the on-road noise was measured for the implementation of a vibrator in an experimental setting. A validation experiment revealed that the harvesting system was optimized to capture power that was approximately 12 times that captured under only on-road noise excitation and 50 times that captured under only the periodic gravity force. Moreover, the investigation of up-sweep excitations with increasing rotational frequency confirmed that stochastic resonance is effective in optimizing the performance of the energy harvester, with a certain bandwidth of vehicle speeds. An actual-vehicle experiment validates that the prototype harvester using stochastic resonance is capable of improving power generation performance for practical tire application.

  6. Magnetic resonance imaging characteristics and the prediction of outcome of vestibular schwannomas following Gamma Knife radiosurgery.

    PubMed

    Wu, Chih-Chun; Guo, Wan-Yuo; Chung, Wen-Yuh; Wu, Hisu-Mei; Lin, Chung-Jung; Lee, Cheng-Chia; Liu, Kang-Du; Yang, Huai-Che

    2017-02-10

    OBJECTIVE Gamma Knife surgery (GKS) is a promising treatment modality for patients with vestibular schwannomas (VSs), but a small percentage of patients have persistent postradiosurgical tumor growth. The aim of this study was to determine the clinical and quantitative MRI features of VS as predictors of long-term tumor control after GKS. METHODS The authors performed a retrospective study of all patients with VS treated with GKS using the Leksell Gamma Knife Unit between 2005 and 2013 at their institution. A total of 187 patients who had a minimum of 24 months of clinical and radiological assessment after radiosurgery were included in this study. Those who underwent a craniotomy with tumor removal before and after GKS were excluded. Study patients comprised 85 (45.5%) males and 102 (54.5%) females, with a median age of 52.2 years (range 20.4-82.3 years). Tumor volumes, enhancing patterns, and apparent diffusion coefficient (ADC) values were measured by region of interest (ROI) analysis of the whole tumor by serial MRI before and after GKS. RESULTS The median follow-up period was 60.8 months (range 24-128.9 months), and the median treated tumor volume was 3.54 cm(3) (0.1-16.2 cm(3)). At last follow-up, imaging studies indicated that 150 tumors (80.2%) showed decreased tumor volume, 20 (10.7%) had stabilized, and 17 (9.1%) continued to grow following radiosurgery. The postradiosurgical outcome was not significantly correlated with pretreatment volumes or postradiosurgical enhancing patterns. Tumors that showed regression within the initial 12 months following radiosurgery were more likely to have a larger volume reduction ratio at last follow-up than those that did not (volume reduction ratio 55% vs 23.6%, respectively; p < 0.001). Compared with solid VSs, cystic VSs were more likely to regress or stabilize in the initial postradiosurgical 6-12-month period and during extended follow-up. Cystic VSs exhibited a greater volume reduction ratio at last follow-up (cystic

  7. Vestibular migraine.

    PubMed

    Furman, Joseph M; Balaban, Carey D

    2015-04-01

    Vestibular migraine is now considered a distinct diagnostic entity by both the Barany Society and the International Headache Society. The recognition of vestibular migraine as a diagnostic entity required decades and was presaged by several reports indicating that a large proportion of patients with migraine headaches have vestibular symptoms and that a large proportion of patients with undiagnosed episodic vestibular symptoms have migraine headache. Despite the availability of diagnostic criteria for vestibular migraine, challenges to diagnosis include variability in terms of the character of dizziness, the presence or absence of clearly defined attacks, the duration of attacks, and the temporal association between headache or other migrainous features and vestibular symptoms. Also, symptoms of vestibular migraine often overlap with symptoms of other causes of dizziness, especially Ménière's disease and benign paroxysmal positional vertigo (BPPV). This article will discuss the demographics, epidemiology, clinical manifestations, physical examination findings, laboratory testing, comorbidities, treatment options, and pathophysiology of vestibular migraine. Future research in the field of vestibular migraine should include both clinical and basic science efforts to better understand the pathophysiology of this condition. Controlled treatment trials for vestibular migraine are desperately needed.

  8. Synchronization and stochastic resonance of the small-world neural network based on the CPG.

    PubMed

    Lu, Qiang; Tian, Juan

    2014-06-01

    According to biological knowledge, the central nervous system controls the central pattern generator (CPG) to drive the locomotion. The brain is a complex system consisting of different functions and different interconnections. The topological properties of the brain display features of small-world network. The synchronization and stochastic resonance have important roles in neural information transmission and processing. In order to study the synchronization and stochastic resonance of the brain based on the CPG, we establish the model which shows the relationship between the small-world neural network (SWNN) and the CPG. We analyze the synchronization of the SWNN when the amplitude and frequency of the CPG are changed and the effects on the CPG when the SWNN's parameters are changed. And we also study the stochastic resonance on the SWNN. The main findings include: (1) When the CPG is added into the SWNN, there exists parameters space of the CPG and the SWNN, which can make the synchronization of the SWNN optimum. (2) There exists an optimal noise level at which the resonance factor Q gets its peak value. And the correlation between the pacemaker frequency and the dynamical response of the network is resonantly dependent on the noise intensity. The results could have important implications for biological processes which are about interaction between the neural network and the CPG.

  9. Stochastic resonance enhancement of small-world neural networks by hybrid synapses and time delay

    NASA Astrophysics Data System (ADS)

    Yu, Haitao; Guo, Xinmeng; Wang, Jiang

    2017-01-01

    The synergistic effect of hybrid electrical-chemical synapses and information transmission delay on the stochastic response behavior in small-world neuronal networks is investigated. Numerical results show that, the stochastic response behavior can be regulated by moderate noise intensity to track the rhythm of subthreshold pacemaker, indicating the occurrence of stochastic resonance (SR) in the considered neural system. Inheriting the characteristics of two types of synapses-electrical and chemical ones, neural networks with hybrid electrical-chemical synapses are of great improvement in neuron communication. Particularly, chemical synapses are conducive to increase the network detectability by lowering the resonance noise intensity, while the information is better transmitted through the networks via electrical coupling. Moreover, time delay is able to enhance or destroy the periodic stochastic response behavior intermittently. In the time-delayed small-world neuronal networks, the introduction of electrical synapses can significantly improve the signal detection capability by widening the range of optimal noise intensity for the subthreshold signal, and the efficiency of SR is largely amplified in the case of pure chemical couplings. In addition, the stochastic response behavior is also profoundly influenced by the network topology. Increasing the rewiring probability in pure chemically coupled networks can always enhance the effect of SR, which is slightly influenced by information transmission delay. On the other hand, the capacity of information communication is robust to the network topology within the time-delayed neuronal systems including electrical couplings.

  10. The effects of nonlinear series resonance on Ohmic and stochastic heating in capacitive discharges

    SciTech Connect

    Lieberman, M. A.; Lichtenberg, A. J.; Kawamura, E.; Mussenbrock, Thomas; Brinkmann, Ralf Peter

    2008-06-15

    The flow of electron and ion conduction currents across a nonlinear capacitive sheath to the electrode surface self-consistently sets the dc bias voltage across the sheath. We incorporate these currents into a model of a homogeneous capacitive sheath in order to determine the enhancement of the Ohmic and stochastic heating due to self-excitation of the nonlinear series resonance in an asymmetric capacitive discharge. At lower pressures, the series resonance can enhance both the Ohmic and stochastic heating by factors of 2-4, with the Ohmic heating tending to zero as the pressure decreases. The model was checked, for a particular set of parameters, by a particle-in-cell (PIC) simulation using the homogeneous sheath approximation, giving good agreement. With a self-consistent Child-law sheath, the PIC simulation showed increased heating, as expected, whether the series resonance is important or not.

  11. Vestibular Migraine

    PubMed Central

    AKDAL, Gülden

    2013-01-01

    The co-occurrence between migraine and vertigo has been noticed for a long time ago. In recent years, however, growing numbers of epidemiological and clinical studies have definitely shown the significant relation between these two diseases. Recently, the term “vestibular migraine” is used commonly in studies. Vestibular migraine has taken place in appendix in the latest International Headache Society Classification. In this review, epidemiology, clinical features, diagnostic criteria and treatment of vesti-bular migraine will be discussed.

  12. Vestibular neuritis.

    PubMed

    Strupp, Michael; Brandt, Thomas

    2009-11-01

    The key signs and symptoms of vestibular neuritis are rotatory vertigo with an acute onset lasting several days, horizontal spontaneous nystagmus (with a rotational component) toward the unaffected ear, a pathologic head-impulse test toward the affected ear, a deviation of the subjective visual vertical toward the affected ear, postural imbalance with falls toward the affected ear, and nausea. The head-impulse test and caloric irrigation show an ipsilateral deficit of the vestibuloocular reflex. Vestibular neuritis is the third most common cause of peripheral vestibular vertigo. It has an annual incidence of 3.5 per 100,000 population and accounts for 7% of the patients at outpatient clinics specializing in the treatment of vertigo. The reactivation of a latent herpes simplex virus type 1 (HSV-1) infection is the most likely cause, as HSV-1 DNA and RNA have been detected in human vestibular ganglia. Vestibular neuritis is a diagnosis of exclusion. Relevant differential diagnoses are vestibular pseudoneuritis due to acute pontomedullary brainstem lesions or cerebellar nodular infarctions, vestibular migraine, and monosymptomatically beginning Ménière's disease. Recovery from vestibular neuritis is due to a combination of (a) peripheral restoration of labyrinthine function, usually incomplete but can be improved by early treatment with corticosteroids, which cause a recovery rate of 62% within 12 months; (b) mainly somatosensory and visual substitution; and (c) central compensation, which can be improved by vestibular exercise.

  13. Stochastic resonance, coherence resonance, and spike timing reliability of Hodgkin-Huxley neurons with ion-channel noise

    NASA Astrophysics Data System (ADS)

    Yu, Haitao; Galán, Roberto F.; Wang, Jiang; Cao, Yibin; Liu, Jing

    2017-04-01

    The random transitions of ion channels between open and closed states are a major source of noise in neurons. In this study, we investigate the stochastic dynamics of a single Hodgkin-Huxley (HH) neuron with realistic, physiological channel noise, which depends on the channel number and the voltage potential of the membrane. Without external input, the stochastic HH model can generate spontaneous spikes induced by ion-channel noise, and the variability of inter-spike intervals attains a minimum for an optimal membrane area, a phenomenon known as coherence resonance. When a subthreshold periodic input current is added, the neuron can optimally detect the input frequency for an intermediate membrane area, corresponding to the phenomenon of stochastic resonance. We also investigate spike timing reliability of neuronal responses to repeated presentations of the same stimulus with different realizations of channel noise. We show that, with increasing membrane area, the reliability of neuronal response decreases for subthreshold periodic inputs, and attains a minimum for suprathreshold inputs. Furthermore, Arnold tongues of high reliability arise in a two-dimensional plot of frequency and amplitude of the sinusoidal input current, resulting from the resonance effect of spike timing reliability.

  14. A digital accelerometer array utilizing suprathreshold stochastic resonance for detection of sub-Brownian noise floor accelerations.

    SciTech Connect

    Carr, Dustin Wade; Olsson, Roy H.

    2004-12-01

    The goal of this LDRD project was to evaluate the possibilities of utilizing Stochastic resonance in micromechanical sensor systems as a means for increasing signal to noise for physical sensors. A careful study of this field reveals that in the case of a single sensing element, stochastic resonance offers no real advantage. We have, however, identified a system that can utilize very similar concepts to stochastic resonance in order to achieve an arrayed sensor system that could be superior to existing technologies in the field of inertial sensors, and could offer a very low power technique for achieving navigation grade inertial measurement units.

  15. Optimizing the Adaptive Stochastic Resonance and Its Application in Fault Diagnosis

    NASA Astrophysics Data System (ADS)

    Liu, Xiaole; Yang, Jianhua; Liu, Houguang; Cheng, Gang; Chen, Xihui; Xu, Dan

    2015-10-01

    This paper presents an adaptive stochastic resonance method based on the improved artificial fish swarm algorithm. By this method, we can enhance the weak characteristic signal which is submerged in a heavy noise. We can also adaptively lead the stochastic resonance to be optimized to the greatest extent. The effectiveness of the proposed method is verified by both numerical simulation and lab experimental vibration signals including normal, a chipped tooth and a missing tooth of planetary gearboxes under the loaded condition. Both theoretical and experimental results show that this method can effectively extract weak characteristics in a heavy noise. In the experiment, each weak fault feature is extracted successfully from the fault planetary gear. When compared with the ensemble empirical mode decomposition (EEMD) method, the method proposed in this paper has been found to give remarkable performance.

  16. Broadband vibration energy harvesting by application of stochastic resonance from rotational environments

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Zheng, R.; Kaizuka, T.; Su, D.; Nakano, K.; Cartmell, M. P.

    2015-11-01

    A model for energy harvesting from a rotating automotive tyre is suggested in which the principle of stochastic resonance is advantageously exploited. A bistable response characteristic is obtained by recourse a small harvester comprising a magnetically repellant configuration in which an instrumented cantilever beam can flip between two physical response states when suitably excited by the rotation of a car wheel into which it is fitted. The rotation of the wheel creates a periodic modulation which enables stochastic resonance to take place and as a consequence of this for energy to be harvested from road noise transmitted through the tyre. An optimised mathematical model of the system is presented based on a series of experimental tests and it is shown that a ten-fold increase in harvested energy over a comparable monostable case is feasible. The suggested application for this harvester is to provide electrical power for a tyre pressure monitoring system.

  17. Role of spin-transfer torques on synchronization and resonance phenomena in stochastic magnetic oscillators

    NASA Astrophysics Data System (ADS)

    Accioly, Artur; Locatelli, Nicolas; Mizrahi, Alice; Querlioz, Damien; Pereira, Luis G.; Grollier, Julie; Kim, Joo-Von

    2016-09-01

    A theoretical study on how synchronization and resonance-like phenomena in superparamagnetic tunnel junctions can be driven by spin-transfer torques is presented. We examine the magnetization of a superparamagnetic free layer that reverses randomly between two well-defined orientations due to thermal fluctuations, acting as a stochastic oscillator. When subject to an external ac forcing, this system can present stochastic resonance and noise-enhanced synchronization. We focus on the roles of the mutually perpendicular damping-like and field-like torques, showing that the response of the system is very different at low and high frequencies. We also demonstrate that the field-like torque can increase the efficiency of the current-driven forcing, especially at sub-threshold electric currents. These results can be useful for possible low-power, more energy efficient applications.

  18. Parameter-induced stochastic resonance based on spectral entropy and its application to weak signal detection

    SciTech Connect

    Zhang, Jinjing; Zhang, Tao

    2015-02-15

    The parameter-induced stochastic resonance based on spectral entropy (PSRSE) method is introduced for the detection of a very weak signal in the presence of strong noise. The effect of stochastic resonance on the detection is optimized using parameters obtained in spectral entropy analysis. Upon processing employing the PSRSE method, the amplitude of the weak signal is enhanced and the noise power is reduced, so that the frequency of the signal can be estimated with greater precision through spectral analysis. While the improvement in the signal-to-noise ratio is similar to that obtained using the Duffing oscillator algorithm, the computational cost reduces from O(N{sup 2}) to O(N). The PSRSE approach is applied to the frequency measurement of a weak signal made by a vortex flow meter. The results are compared with those obtained applying the Duffing oscillator algorithm.

  19. Stochastic resonant damping in a noisy monostable system: theory and experiment.

    PubMed

    Volpe, Giovanni; Perrone, Sandro; Rubi, J Miguel; Petrov, Dmitri

    2008-05-01

    Usually in the presence of a background noise an increased effort put in controlling a system stabilizes its behavior. Rarely it is thought that an increased control of the system can lead to a looser response and, therefore, to a poorer performance. Strikingly there are many systems that show this weird behavior; examples can be drawn form physical, biological, and social systems. Until now no simple and general mechanism underlying such behaviors has been identified. Here we show that such a mechanism, named stochastic resonant damping, can be provided by the interplay between the background noise and the control exerted on the system. We experimentally verify our prediction on a physical model system based on a colloidal particle held in an oscillating optical potential. Our result adds a tool for the study of intrinsically noisy phenomena, joining the many constructive facets of noise identified in the past decades-for example, stochastic resonance, noise-induced activation, and Brownian ratchets.

  20. Algebraic Information Theory and Stochastic Resonance for Binary-Input Binary-Output Channels

    DTIC Science & Technology

    2012-03-01

    invertible channel matrices. In Proc. 44th Annual Conf. on Information Sciences and Systems, CISS 2010, Princeton, NJ, USA, March 2010. [4] J. Hopfield ...Neural networks and physical systems with emergent collective computational abilities. Proceedings of the National Academy of Sciences of the USA, 79...2554–2558, April 1982. [5] Bart Kosko and Sanya Mitiam. Stochastic resonance in noisy threshold neurons. Neural Networks , 16:755–761, 2003. [6] Bart

  1. Stochastic resonance in a pulse neural network with a propagational time delay.

    PubMed

    Kanamaru, T; Okabe, Y

    2000-01-01

    Stochastic resonance in a coupled FitzHugh-Nagumo equation with a propagational time delay is investigated. With an appropriate set of parameter values. i.e. the frequency of the periodic input, the propagational time delay, and the coupling strength, a deterministic firing induced by additive noise is observed, and its dependence on the number of neurons is examined. It is also found that a network composed of two assemblies shows a competitive behavior under control of the noise intensity.

  2. Functional Stochastic Resonance in the Human Brain: Noise Induced Sensitization of Baroreflex System

    NASA Astrophysics Data System (ADS)

    Hidaka, Ichiro; Nozaki, Daichi; Yamamoto, Yoshiharu

    2000-10-01

    We demonstrate experimentally that noise can enhance the homeostatic function in the human blood pressure regulatory system. The results show that the compensatory heart rate response to the weak periodic signal introduced at the venous blood pressure receptor is optimized by adding noise to the arterial blood pressure receptor. We conclude that this functional stochastic resonance most likely results from the interaction of noise with signal in the brain stem, where the neuronal inputs from these two different receptors first join together.

  3. Friction-induced Resonance of a Stochastic Oscillator

    SciTech Connect

    Laas, K.; Mankin, R.

    2009-10-29

    The influence of the friction coefficient on the long-time behavior of the output signal of a harmonic oscillator with fluctuating frequency subjected to an external periodic force and an additive thermal noise is considered. The colored fluctuations of the oscillator frequency are modeled as a three-level Markovian telegraph noise. The main purpose of this work is to demonstrate, based on exact expressions, that the resonance is manifested in the dependence of the response function and the complex susceptibility of the oscillator upon the friction coefficient. The advantage of the latter effect is that the control parameter is the damping coefficient, which can easily be varied in possible experiments as well as potential technological applications.

  4. Possible breakthrough: Significant improvement of signal to noise ratio by stochastic resonance

    SciTech Connect

    Kiss, L.B.

    1996-06-01

    The {ital simplest} {ital stochastic} {ital resonator} {ital is} {ital used}, {ital a} {ital level} {ital crossing} {ital detector} (LCD), to investigate key properties of stochastic resonance (SR). It is pointed out that successful signal processing and biological applications of SR require to work in the {ital large} {ital signal} {ital limit} (nonlinear transfer limit) which requires a completely new approach: {ital wide} {ital band} {ital input} {ital signal} and a {ital new}, {ital generalised} {ital definition} {ital of} {ital output} {ital noise}. The new way of approach is illustrated by a new arrangement. The arrangement employs a special LCD, white input noise and a special, large, subthreshold wide band signal. {ital First} {ital time} {ital in} {ital the} {ital history} {ital of} {ital SR} (for a wide band input noise), the {ital signal} {ital to} {ital noise} {ital ratio} {ital becomes} {ital much} {ital higher} {ital at} {ital the} {ital output} of a stochastic resonator than {ital at} {ital its} {ital input}. In that way, SR is proven to have a potential to improve signal transfer. Note, that the new arrangement seems to have resemblance to {ital neurone} {ital models}, therefore, it has a potential also for biological applications. {copyright} {ital 1996 American Institute of Physics.}

  5. Effects of time delay on stochastic resonance of the stock prices in financial system

    NASA Astrophysics Data System (ADS)

    Li, Jiang-Cheng; Li, Chun; Mei, Dong-Cheng

    2014-06-01

    The effect of time delay on stochastic resonance of the stock prices in finance system was investigated. The time delay is introduced into the Heston model driven by the extrinsic and intrinsic periodic information for stock price. The signal power amplification (SPA) was calculated by numerical simulation. The results indicate that an optimal critical value of delay time maximally enhances the reverse-resonance in the behaviors of SPA as a function of long-run variance of volatility or cross correlation coefficient between noises for both cases of intrinsic and extrinsic periodic information. Moreover, in both cases, being a critical value in the delay time, when the delay time takes value below the critical value, reverse-resonance increases with the delay time increasing, however, when the delay time takes value above the critical value, the reverse-resonance decrease with the delay time increasing.

  6. Far from Equilibrium Percolation, Stochastic and Shape Resonances in the Physics of Life

    PubMed Central

    Poccia, Nicola; Ansuini, Alessio; Bianconi, Antonio

    2011-01-01

    Key physical concepts, relevant for the cross-fertilization between condensed matter physics and the physics of life seen as a collective phenomenon in a system out-of-equilibrium, are discussed. The onset of life can be driven by: (a) the critical fluctuations at the protonic percolation threshold in membrane transport; (b) the stochastic resonance in biological systems, a mechanism that can exploit external and self-generated noise in order to gain efficiency in signal processing; and (c) the shape resonance (or Fano resonance or Feshbach resonance) in the association and dissociation processes of bio-molecules (a quantum mechanism that could play a key role to establish a macroscopic quantum coherence in the cell). PMID:22072921

  7. Far from equilibrium percolation, stochastic and shape resonances in the physics of life.

    PubMed

    Poccia, Nicola; Ansuini, Alessio; Bianconi, Antonio

    2011-01-01

    Key physical concepts, relevant for the cross-fertilization between condensed matter physics and the physics of life seen as a collective phenomenon in a system out-of-equilibrium, are discussed. The onset of life can be driven by: (a) the critical fluctuations at the protonic percolation threshold in membrane transport; (b) the stochastic resonance in biological systems, a mechanism that can exploit external and self-generated noise in order to gain efficiency in signal processing; and (c) the shape resonance (or Fano resonance or Feshbach resonance) in the association and dissociation processes of bio-molecules (a quantum mechanism that could play a key role to establish a macroscopic quantum coherence in the cell).

  8. Effects of time delay and random rewiring on the stochastic resonance in excitable small-world neuronal networks

    NASA Astrophysics Data System (ADS)

    Yu, Haitao; Wang, Jiang; Du, Jiwei; Deng, Bin; Wei, Xile; Liu, Chen

    2013-05-01

    The effects of time delay and rewiring probability on stochastic resonance and spatiotemporal order in small-world neuronal networks are studied in this paper. Numerical results show that, irrespective of the pacemaker introduced to one single neuron or all neurons of the network, the phenomenon of stochastic resonance occurs. The time delay in the coupling process can either enhance or destroy stochastic resonance on small-world neuronal networks. In particular, appropriately tuned delays can induce multiple stochastic resonances, which appear intermittently at integer multiples of the oscillation period of the pacemaker. More importantly, it is found that the small-world topology can significantly affect the stochastic resonance on excitable neuronal networks. For small time delays, increasing the rewiring probability can largely enhance the efficiency of pacemaker-driven stochastic resonance. We argue that the time delay and the rewiring probability both play a key role in determining the ability of the small-world neuronal network to improve the noise-induced outreach of the localized subthreshold pacemaker.

  9. Effects of time delay and random rewiring on the stochastic resonance in excitable small-world neuronal networks.

    PubMed

    Yu, Haitao; Wang, Jiang; Du, Jiwei; Deng, Bin; Wei, Xile; Liu, Chen

    2013-05-01

    The effects of time delay and rewiring probability on stochastic resonance and spatiotemporal order in small-world neuronal networks are studied in this paper. Numerical results show that, irrespective of the pacemaker introduced to one single neuron or all neurons of the network, the phenomenon of stochastic resonance occurs. The time delay in the coupling process can either enhance or destroy stochastic resonance on small-world neuronal networks. In particular, appropriately tuned delays can induce multiple stochastic resonances, which appear intermittently at integer multiples of the oscillation period of the pacemaker. More importantly, it is found that the small-world topology can significantly affect the stochastic resonance on excitable neuronal networks. For small time delays, increasing the rewiring probability can largely enhance the efficiency of pacemaker-driven stochastic resonance. We argue that the time delay and the rewiring probability both play a key role in determining the ability of the small-world neuronal network to improve the noise-induced outreach of the localized subthreshold pacemaker.

  10. Experimental evidence for multi-element stochastic resonance in the system of membrane ion channels

    NASA Astrophysics Data System (ADS)

    Vodyanoy, Igor

    1996-03-01

    The principles of biological amplification are far from understood; it is only clear that biological amplifiers are unique in their ability to detect small signals in a noisy environment. As was shown recently, many nonlinear systems can use noise to enhance their performance, and this phenomenon, called stochastic resonance, may underline the extraordinary ability of some biological systems to detect and amplify small signals. Previous work has demonstrated stochastic resonance in complex systems of biological transducers and neural signal pathways, but the possibility that it could occur at the sub-cellular level has remained open. Here we report the observation of noise-enhanced electrical signal transfer in a simple system of voltage-dependent ion channels formed by the peptide alamethicin in a lipid bilayer footnote S.M.Bezrukov and I.Vodyanoy, Nature (London), November 1995 (in press). Channels are expressed in a stochastic manner as "current bursts" rising from the background, and their formation is highly voltage-sensitive. An average alamethicin- induced conductance increases e-fold every 4 or 5 mV, depending on bilayer lipid composition. Alamethicin channel transitions between nonconducting and conducting aggregates can be described by a quasi-bistable energy diagram, where the probability distribution along the reaction coordinate is sensitive to the transmembrane voltage mostly at the level of the transition between two main energy wells. To study the interaction between external noise and signal transfer, we measure amplitude of output signal and the signal-to-noise ratio at the system output as a function of external noise intensity. We show that a hundred-fold increase in signal transduction induced by external noise is accompanied by a growth in the output signal-to-noise ratio. Recent theory and numerical simulation dealing with a parallel combination of noniteracting stochastic resonant elements may provide an explanation of the present results

  11. Channel noise enhances signal detectability in a model of acoustic neuron through the stochastic resonance paradigm.

    PubMed

    Liberti, M; Paffi, A; Maggio, F; De Angelis, A; Apollonio, F; d'Inzeo, G

    2009-01-01

    A number of experimental investigations have evidenced the extraordinary sensitivity of neuronal cells to weak input stimulations, including electromagnetic (EM) fields. Moreover, it has been shown that biological noise, due to random channels gating, acts as a tuning factor in neuronal processing, according to the stochastic resonant (SR) paradigm. In this work the attention is focused on noise arising from the stochastic gating of ionic channels in a model of Ranvier node of acoustic fibers. The small number of channels gives rise to a high noise level, which is able to cause a spike train generation even in the absence of stimulations. A SR behavior has been observed in the model for the detection of sinusoidal signals at frequencies typical of the speech.

  12. Effects of spike-time-dependent plasticity on the stochastic resonance of small-world neuronal networks

    SciTech Connect

    Yu, Haitao; Guo, Xinmeng; Wang, Jiang Deng, Bin; Wei, Xile

    2014-09-01

    The phenomenon of stochastic resonance in Newman-Watts small-world neuronal networks is investigated when the strength of synaptic connections between neurons is adaptively adjusted by spike-time-dependent plasticity (STDP). It is shown that irrespective of the synaptic connectivity is fixed or adaptive, the phenomenon of stochastic resonance occurs. The efficiency of network stochastic resonance can be largely enhanced by STDP in the coupling process. Particularly, the resonance for adaptive coupling can reach a much larger value than that for fixed one when the noise intensity is small or intermediate. STDP with dominant depression and small temporal window ratio is more efficient for the transmission of weak external signal in small-world neuronal networks. In addition, we demonstrate that the effect of stochastic resonance can be further improved via fine-tuning of the average coupling strength of the adaptive network. Furthermore, the small-world topology can significantly affect stochastic resonance of excitable neuronal networks. It is found that there exists an optimal probability of adding links by which the noise-induced transmission of weak periodic signal peaks.

  13. Effects of spike-time-dependent plasticity on the stochastic resonance of small-world neuronal networks.

    PubMed

    Yu, Haitao; Guo, Xinmeng; Wang, Jiang; Deng, Bin; Wei, Xile

    2014-09-01

    The phenomenon of stochastic resonance in Newman-Watts small-world neuronal networks is investigated when the strength of synaptic connections between neurons is adaptively adjusted by spike-time-dependent plasticity (STDP). It is shown that irrespective of the synaptic connectivity is fixed or adaptive, the phenomenon of stochastic resonance occurs. The efficiency of network stochastic resonance can be largely enhanced by STDP in the coupling process. Particularly, the resonance for adaptive coupling can reach a much larger value than that for fixed one when the noise intensity is small or intermediate. STDP with dominant depression and small temporal window ratio is more efficient for the transmission of weak external signal in small-world neuronal networks. In addition, we demonstrate that the effect of stochastic resonance can be further improved via fine-tuning of the average coupling strength of the adaptive network. Furthermore, the small-world topology can significantly affect stochastic resonance of excitable neuronal networks. It is found that there exists an optimal probability of adding links by which the noise-induced transmission of weak periodic signal peaks.

  14. Abnormal Magnetic Resonance Imaging Findings in Patients With Sudden Sensorineural Hearing Loss: Vestibular Schwannoma as the Most Common Cause of MRI Abnormality.

    PubMed

    Jeong, Kyung-Hwa; Choi, Jin Woo; Shin, Jung Eun; Kim, Chang-Hee

    2016-04-01

    The etiology of sudden sensorineural hearing loss (SSNHL) remains unclear in most cases. This study aimed to assess abnormal magnetic resonance imaging (MRI) findings in patients with SSNHL and evaluate the value of MRI in identifying the cause of SSNHL.A retrospective analysis of the charts and MRI findings of 291 patients with SSNHL was performed.In 291 patients, MRI abnormality, which was considered a cause of SSNHL, was detected in 13 patients. Vestibular schwannoma involving the internal auditory canal (IAC) and/or cerebellopontine angle was observed in 9 patients. All 9 patients had intrameatal tumors, and 6 of the 9 patients displayed extrameatal extension of their tumors. The tumor was small (<1 cm) or medium-sized (1.1-2.9 cm) in these 6 patients. Intralabyrinthine schwannoma, labyrinthine hemorrhage, IAC metastasis, and a ruptured dermoid cyst were each observed in 1 patient.The most commonly observed MRI abnormality in patients with SSNHL was vestibular schwannoma, and all of the lesions were small or medium-sized tumors involving the IAC.

  15. Three dimensional nuclear magnetic resonance spectroscopic imaging of sodium ions using stochastic excitation and oscillating gradients

    SciTech Connect

    Frederick, Blaise deBonneval

    1994-12-01

    Nuclear magnetic resonance (NMR) spectroscopic imaging of 23Na holds promise as a non-invasive method of mapping Na{sup +} distributions, and for differentiating pools of Na+ ions in biological tissues. However, due to NMR relaxation properties of 23Na in vivo, a large fraction of Na+ is not visible with conventional NMR imaging methods. An alternate imaging method, based on stochastic excitation and oscillating gradients, has been developed which is well adapted to measuring nuclei with short T2. Contemporary NMR imaging techniques have dead times of up to several hundred microseconds between excitation and sampling, comparable to the shortest in vivo 23Na T2 values, causing significant signal loss. An imaging strategy based on stochastic excitation has been developed which greatly reduces experiment dead time by reducing peak radiofrequency (RF) excitation power and using a novel RF circuit to speed probe recovery. Continuously oscillating gradients are used to eliminate transient eddy currents. Stochastic 1H and 23Na spectroscopic imaging experiments have been performed on a small animal system with dead times as low as 25μs, permitting spectroscopic imaging with 100% visibility in vivo. As an additional benefit, the encoding time for a 32x32x32 spectroscopic image is under 30 seconds. The development and analysis of stochastic NMR imaging has been hampered by limitations of the existing phase demodulation reconstruction technique. Three dimensional imaging was impractical due to reconstruction time, and design and analysis of proposed experiments was limited by the mathematical intractability of the reconstruction method. A new reconstruction method for stochastic NMR based on Fourier interpolation has been formulated combining the advantage of a several hundredfold reduction in reconstruction time with a straightforward mathematical form.

  16. Noninvasive control of stochastic resonance and an analysis of multistable oscillators

    NASA Astrophysics Data System (ADS)

    Mason, Jonathan Peter

    2001-08-01

    In this work, we look at two different types of dynamical systems. In the first type, we investigate a group of techniques with the goal of enhancing stochastic resonance in a bistable system. These methods involve adding external feedback into the system to make the transitions between the two wells in the bistable system more likely. In the second type, we also investigate adding pulsatile input into a dynamical system. This system is a second order linear differential equation, but the addition of the pulses to it makes behave in a nonlinear fashion. The combination of the natural ``ringing down'' of the system with the pulses act as a ``stretching and folding'' that leads to global stability and a number of coexisting multistable orbits. In studying the bistable system exhibiting stochastic resonance, we note that external feedback can enhance (or depress) the response of a noisy bistable system to monochromatic signals, significantly magnifying its natural stochastic resonance. We compare and contrast a variety of such feedback strategies, using both numerical simulations and analog electronic experiments. These noninvasive control techniques are especially valuable for noisy bistable systems that are difficult or impossible to modify internally, such as in neuronal systems. In our analysis of multistable oscillators, a model system is proposed which possesses numerous stable coexisting oscillatory solutions and does not require delayed feedback. This system is inspired by a study of multistable dynamics in biological models of electrical activity in bursting neurons. The model is a second-order underdamped linear system that receives periodic pulsatile input over a sub region of the circuit variables' state-space. Numerical methods are presented for determining the existence and stability of these oscillatory solutions and the scaling properties of the number of coexisting periodic solutions are investigated.

  17. Entropic stochastic resonance of a flexible polymer chain in a confined system

    NASA Astrophysics Data System (ADS)

    Zhang, Zhen; Chen, Hanshuang; Hou, Zhonghuai

    2012-07-01

    We have studied the dynamics of a flexible polymer chain in constrained dumb-bell-shape geometry subject to a periodic force and external noise along the longitudinal direction. It is found that the system exhibits a feature of entropic stochastic resonance (ESR), i.e., the temporal coherence of the polymer motion can reach a maximum level for an optimal noise intensity. We demonstrate that the occurrence of ESR is robust to the change of chain length, while the bottleneck width should be properly chosen. A gravity force in the vertical direction is not necessary for the ESR here, however, the elastic coupling between polymer beads is crucial.

  18. Note: On-line weak signal detection via adaptive stochastic resonance

    SciTech Connect

    Lu, Siliang; He, Qingbo Kong, Fanrang

    2014-06-15

    We design an instrument with a novel embedded adaptive stochastic resonance (SR) algorithm that consists of a SR module and a digital zero crossing detection module for on-line weak signal detection in digital signal processing applications. The two modules are responsible for noise filtering and adaptive parameter configuration, respectively. The on-line weak signal detection can be stably achieved in seconds. The prototype instrument exhibits an advance of 20 dB averaged signal-to-noise ratio and 5 times averaged adjust R-square as compared to the input noisy signal, in considering different driving frequencies and noise levels.

  19. Conductance with stochastic resonance in Mn{sub 12} redox network without tuning

    SciTech Connect

    Hirano, Yoshiaki; Segawa, Yuji; Kawai, Tomoji; Kuroda-Sowa, Takayoshi; Matsumoto, Takuya

    2014-06-09

    Artificial neuron-based information processing is one of the attractive approaches of molecular-scale electronics, which can exploit the ability of molecular system for self-assembling or self-organization. The self-organized Mn{sub 12}/DNA redox network shows nonlinear current-voltage characteristics that can be described by the Coulomb blockade network model. As a demonstration of the nonlinear network system, we have observed stochastic resonance without tuning for weak periodic input signals and thermal noise, which suggests a route to neural network composed of molecular materials.

  20. Stochastic resonance in a fractional harmonic oscillator subject to random mass and signal-modulated noise

    NASA Astrophysics Data System (ADS)

    Guo, Feng; Zhu, Cheng-Yin; Cheng, Xiao-Feng; Li, Heng

    2016-10-01

    Stochastic resonance in a fractional harmonic oscillator with random mass and signal-modulated noise is investigated. Applying linear system theory and the characteristics of the noises, the analysis expression of the mean output-amplitude-gain (OAG) is obtained. It is shown that the OAG varies non-monotonically with the increase of the intensity of the multiplicative dichotomous noise, with the increase of the frequency of the driving force, as well as with the increase of the system frequency. In addition, the OAG is a non-monotonic function of the system friction coefficient, as a function of the viscous damping coefficient, as a function of the fractional exponent.

  1. Dissipative Double-Well Potential for Cold Atoms: Kramers Rate and Stochastic Resonance

    NASA Astrophysics Data System (ADS)

    Stroescu, Ion; Hume, David B.; Oberthaler, Markus K.

    2016-12-01

    We experimentally study particle exchange in a dissipative double-well potential using laser-cooled atoms in a hybrid trap. We measure the particle hopping rate as a function of barrier height, temperature, and atom number. Single-particle resolution allows us to measure rates over more than 4 orders of magnitude and distinguish the effects of loss and hopping. Deviations from the Arrhenius-law scaling at high barrier heights occur due to cold collisions between atoms within a well. By driving the system periodically, we characterize the phenomenon of stochastic resonance in the system response.

  2. Dissipative Double-Well Potential for Cold Atoms: Kramers Rate and Stochastic Resonance.

    PubMed

    Stroescu, Ion; Hume, David B; Oberthaler, Markus K

    2016-12-09

    We experimentally study particle exchange in a dissipative double-well potential using laser-cooled atoms in a hybrid trap. We measure the particle hopping rate as a function of barrier height, temperature, and atom number. Single-particle resolution allows us to measure rates over more than 4 orders of magnitude and distinguish the effects of loss and hopping. Deviations from the Arrhenius-law scaling at high barrier heights occur due to cold collisions between atoms within a well. By driving the system periodically, we characterize the phenomenon of stochastic resonance in the system response.

  3. Non-linear resonant coupling of tsunami edge waves using stochastic earthquake source models

    NASA Astrophysics Data System (ADS)

    Geist, Eric L.

    2016-02-01

    Non-linear resonant coupling of edge waves can occur with tsunamis generated by large-magnitude subduction zone earthquakes. Earthquake rupture zones that straddle beneath the coastline of continental margins are particularly efficient at generating tsunami edge waves. Using a stochastic model for earthquake slip, it is shown that a wide range of edge-wave modes and wavenumbers can be excited, depending on the variability of slip. If two modes are present that satisfy resonance conditions, then a third mode can gradually increase in amplitude over time, even if the earthquake did not originally excite that edge-wave mode. These three edge waves form a resonant triad that can cause unexpected variations in tsunami amplitude long after the first arrival. An M ˜ 9, 1100 km-long continental subduction zone earthquake is considered as a test case. For the least-variable slip examined involving a Gaussian random variable, the dominant resonant triad includes a high-amplitude fundamental mode wave with wavenumber associated with the along-strike dimension of rupture. The two other waves that make up this triad include subharmonic waves, one of fundamental mode and the other of mode 2 or 3. For the most variable slip examined involving a Cauchy-distributed random variable, the dominant triads involve higher wavenumbers and modes because subevents, rather than the overall rupture dimension, control the excitation of edge waves. Calculation of the resonant period for energy transfer determines which cases resonant coupling may be instrumentally observed. For low-mode triads, the maximum transfer of energy occurs approximately 20-30 wave periods after the first arrival and thus may be observed prior to the tsunami coda being completely attenuated. Therefore, under certain circumstances the necessary ingredients for resonant coupling of tsunami edge waves exist, indicating that resonant triads may be observable and implicated in late, large-amplitude tsunami arrivals.

  4. Non-linear resonant coupling of tsunami edge waves using stochastic earthquake source models

    USGS Publications Warehouse

    Geist, Eric L.

    2016-01-01

    Non-linear resonant coupling of edge waves can occur with tsunamis generated by large-magnitude subduction zone earthquakes. Earthquake rupture zones that straddle beneath the coastline of continental margins are particularly efficient at generating tsunami edge waves. Using a stochastic model for earthquake slip, it is shown that a wide range of edge-wave modes and wavenumbers can be excited, depending on the variability of slip. If two modes are present that satisfy resonance conditions, then a third mode can gradually increase in amplitude over time, even if the earthquake did not originally excite that edge-wave mode. These three edge waves form a resonant triad that can cause unexpected variations in tsunami amplitude long after the first arrival. An M ∼ 9, 1100 km-long continental subduction zone earthquake is considered as a test case. For the least-variable slip examined involving a Gaussian random variable, the dominant resonant triad includes a high-amplitude fundamental mode wave with wavenumber associated with the along-strike dimension of rupture. The two other waves that make up this triad include subharmonic waves, one of fundamental mode and the other of mode 2 or 3. For the most variable slip examined involving a Cauchy-distributed random variable, the dominant triads involve higher wavenumbers and modes because subevents, rather than the overall rupture dimension, control the excitation of edge waves. Calculation of the resonant period for energy transfer determines which cases resonant coupling may be instrumentally observed. For low-mode triads, the maximum transfer of energy occurs approximately 20–30 wave periods after the first arrival and thus may be observed prior to the tsunami coda being completely attenuated. Therefore, under certain circumstances the necessary ingredients for resonant coupling of tsunami edge waves exist, indicating that resonant triads may be observable and implicated in late, large-amplitude tsunami arrivals.

  5. Lévy stable noise-induced transitions: stochastic resonance, resonant activation and dynamic hysteresis

    NASA Astrophysics Data System (ADS)

    Dybiec, Bartłomiej; Gudowska-Nowak, Ewa

    2009-05-01

    A standard approach to analysis of noise-induced effects in stochastic dynamics assumes a Gaussian character of the noise term describing interaction of the analyzed system with its complex surroundings. An additional assumption about the existence of timescale separation between the dynamics of the measured observable and the typical timescale of the noise allows external fluctuations to be modeled as temporally uncorrelated and therefore white. However, in many natural phenomena the assumptions concerning the above mentioned properties of 'Gaussianity' and 'whiteness' of the noise can be violated. In this context, in contrast to the spatiotemporal coupling characterizing general forms of non-Markovian or semi-Markovian Lévy walks, so called Lévy flights correspond to the class of Markov processes which can still be interpreted as white, but distributed according to a more general, infinitely divisible, stable and non-Gaussian law. Lévy noise-driven non-equilibrium systems are known to manifest interesting physical properties and have been addressed in various scenarios of physical transport exhibiting a superdiffusive behavior. Here we present a brief overview of our recent investigations aimed at understanding features of stochastic dynamics under the influence of Lévy white noise perturbations. We find that the archetypal phenomena of noise-induced ordering are robust and can be detected also in systems driven by memoryless, non-Gaussian, heavy-tailed fluctuations with infinite variance.

  6. The cavity resonator design: stochastic optimization of the transmission line method

    NASA Astrophysics Data System (ADS)

    Jurečka, Stanislav; Müllerová, Jarmila; Dado, Milan

    2012-02-01

    Stable cavity resonators provide an ideal solution for high quality applications in telecommunications, laser sources, sensors, oscillators and filters, instrumentation and other large area of applications. For the determination of the electromagnetic field (EMF) properties in a cavity resonator several numerical methods are widely used. In our approach we used the transmission line modeling method (TLM). It is a wide-band time-domain numerical method suitable for solution of the electromagnetic field in a studied region. TLM method is based on the isomorphism between the theory of passive electrical network and the wave equation describing the properties of the EMF. TLM method offers two important advantages over the time-domain techniques such as the finite-difference time domain methods. The electric and magnetic field are resolved synchronously in time and space and TLM in implicitly stable method due to the mapping to electrical circuits. The EMF in the rectangular cavity is in our approach determined by the TLM method and the frequency spectrum is computed by the Fourier transform of the time signal. The theoretical model of the cavity EMF power spectral density function contains information about the geometrical configuration of the resonator. In our work we use the genetic algorithm for the determination of optimal dimensions of the cavity resonator expected for the proposed output resonant frequency. The stochastic modification of the theoretical model parameters is controlled by the genetic operators of mutation, crossover and selection, leading to overall improvement of the theoretical model estimation during the optimization process.

  7. The cavity resonator design: stochastic optimization of the transmission line method

    NASA Astrophysics Data System (ADS)

    Jurečka, Stanislav; Müllerová, Jarmila; Dado, Milan

    2011-09-01

    Stable cavity resonators provide an ideal solution for high quality applications in telecommunications, laser sources, sensors, oscillators and filters, instrumentation and other large area of applications. For the determination of the electromagnetic field (EMF) properties in a cavity resonator several numerical methods are widely used. In our approach we used the transmission line modeling method (TLM). It is a wide-band time-domain numerical method suitable for solution of the electromagnetic field in a studied region. TLM method is based on the isomorphism between the theory of passive electrical network and the wave equation describing the properties of the EMF. TLM method offers two important advantages over the time-domain techniques such as the finite-difference time domain methods. The electric and magnetic field are resolved synchronously in time and space and TLM in implicitly stable method due to the mapping to electrical circuits. The EMF in the rectangular cavity is in our approach determined by the TLM method and the frequency spectrum is computed by the Fourier transform of the time signal. The theoretical model of the cavity EMF power spectral density function contains information about the geometrical configuration of the resonator. In our work we use the genetic algorithm for the determination of optimal dimensions of the cavity resonator expected for the proposed output resonant frequency. The stochastic modification of the theoretical model parameters is controlled by the genetic operators of mutation, crossover and selection, leading to overall improvement of the theoretical model estimation during the optimization process.

  8. The resonance overlap criterion and the onset of stochastic behavior in the restricted three-body problem

    NASA Technical Reports Server (NTRS)

    Wisdom, J.

    1980-01-01

    The resonance overlap criterion for the onset of stochastic behavior is applied to the planar circular-restricted three-body problem with small mass ratio (mu). Its predictions for mu = 0.001, 0.0001, and 0.00001 are compared to the transitions observed in the numerically determined Kolmogorov-Sinai entropy and found to be in remarkably good agreement. In addition, an approximate scaling law for the onset of stochastic behavior is derived.

  9. A novel diversiform stochastic resonance of a domain wall and its performance at different states

    NASA Astrophysics Data System (ADS)

    Zhang, Haibin; Ouyang, Kesai; He, Qingbo; Kong, Fanrang

    2016-03-01

    The response of an underdamped stochastic resonance (SR) with a new pining potential model of domain wall (DW) in ferromagnetic strips driven by additive Gaussian white noise to an additive weak harmonic forcing is investigated. We address that the new nonlinear system can be converted between bi-stable and mono-stable freely by tuning the system parameters. Analytical expressions of signal-to-noise ratio (SNR) of the bi-stable stage is obtained based on the linear response theory. In addition, another type of SR, which occurs when the system is mono-stable, is also reported with the intrinsic frequency derived analytically. The SR in mono-stable stage confirms to the typical physical resonance better with frequency-selection characteristic. Numerical simulation of both stages is carried out with outputs conforming to the theoretical derivation. Owing to the diversity of potential model, the new system possesses considerable merits for engineering applications.

  10. Self-organization of a neural network with heterogeneous neurons enhances coherence and stochastic resonance

    NASA Astrophysics Data System (ADS)

    Li, Xiumin; Zhang, Jie; Small, Michael

    2009-03-01

    Most network models for neural behavior assume a predefined network topology and consist of almost identical elements exhibiting little heterogeneity. In this paper, we propose a self-organized network consisting of heterogeneous neurons with different behaviors or degrees of excitability. The synaptic connections evolve according to the spike-timing dependent plasticity mechanism and finally a sparse and active-neuron-dominant structure is observed. That is, strong connections are mainly distributed to the synapses from active neurons to inactive ones. We argue that this self-emergent topology essentially reflects the competition of different neurons and encodes the heterogeneity. This structure is shown to significantly enhance the coherence resonance and stochastic resonance of the entire network, indicating its high efficiency in information processing.

  11. Stochastic resonance whole-body vibration improves postural control in health care professionals: a worksite randomized controlled trial.

    PubMed

    Elfering, Achim; Schade, Volker; Stoecklin, Lukas; Baur, Simone; Burger, Christian; Radlinger, Lorenz

    2014-05-01

    Slip, trip, and fall injuries are frequent among health care workers. Stochastic resonance whole-body vibration training was tested to improve postural control. Participants included 124 employees of a Swiss university hospital. The randomized controlled trial included an experimental group given 8 weeks of training and a control group with no intervention. In both groups, postural control was assessed as mediolateral sway on a force plate before and after the 8-week trial. Mediolateral sway was significantly decreased by stochastic resonance whole-body vibration training in the experimental group but not in the control group that received no training (p < .05). Stochastic resonance whole-body vibration training is an option in the primary prevention of balance-related injury at work.

  12. A framework to analyze the stochastic harmonics and resonance of wind energy grid interconnection

    DOE PAGES

    Cho, Youngho; Lee, Choongman; Hur, Kyeon; ...

    2016-08-31

    This study addresses a modeling and analysis methodology for investigating the stochastic harmonics and resonance concerns of wind power plants (WPPs). Wideband harmonics from modern wind turbines are observed to be stochastic, associated with real power production, and they may adversely interact with the grid impedance and cause unexpected harmonic resonance if not comprehensively addressed in the planning and commissioning of the WPPs. These issues should become more critical as wind penetration levels increase. We thus propose a planning study framework comprising the following functional steps: First, the best-fitted probability density functions (PDFs) of the harmonic components of interest inmore » the frequency domain are determined. In operations planning, maximum likelihood estimations followed by a chi-square test are used once field measurements or manufacturers' data are available. Second, harmonic currents from the WPP are represented by randomly-generating harmonic components based on their PDFs (frequency spectrum) and then synthesized for time-domain simulations via inverse Fourier transform. Finally, we conduct a comprehensive assessment by including the impacts of feeder configurations, harmonic filters, and the variability of parameters. We demonstrate the efficacy of the proposed study approach for a 100-MW offshore WPP consisting of 20 units of 5-MW full-converter turbines, a realistic benchmark system adapted from a WPP under development in Korea, and discuss lessons learned through this research.« less

  13. A framework to analyze the stochastic harmonics and resonance of wind energy grid interconnection

    SciTech Connect

    Cho, Youngho; Lee, Choongman; Hur, Kyeon; Kang, Yong Cheol; Muljadi, Eduard; Park, Sang -Ho; Choy, Young -Do; Yoon, Gi -Gab

    2016-08-31

    This study addresses a modeling and analysis methodology for investigating the stochastic harmonics and resonance concerns of wind power plants (WPPs). Wideband harmonics from modern wind turbines are observed to be stochastic, associated with real power production, and they may adversely interact with the grid impedance and cause unexpected harmonic resonance if not comprehensively addressed in the planning and commissioning of the WPPs. These issues should become more critical as wind penetration levels increase. We thus propose a planning study framework comprising the following functional steps: First, the best-fitted probability density functions (PDFs) of the harmonic components of interest in the frequency domain are determined. In operations planning, maximum likelihood estimations followed by a chi-square test are used once field measurements or manufacturers' data are available. Second, harmonic currents from the WPP are represented by randomly-generating harmonic components based on their PDFs (frequency spectrum) and then synthesized for time-domain simulations via inverse Fourier transform. Finally, we conduct a comprehensive assessment by including the impacts of feeder configurations, harmonic filters, and the variability of parameters. We demonstrate the efficacy of the proposed study approach for a 100-MW offshore WPP consisting of 20 units of 5-MW full-converter turbines, a realistic benchmark system adapted from a WPP under development in Korea, and discuss lessons learned through this research.

  14. Effects of auditory noise on the psychophysical detection of visual signals: cross-modal stochastic resonance.

    PubMed

    Manjarrez, Elias; Mendez, Ignacio; Martinez, Lourdes; Flores, Amira; Mirasso, Claudio R

    2007-03-30

    Harper [D.W. Harper, Signal detection analysis of effect of white noise intensity on sensitivity to visual flicker, Percept. Mot. Skills 48 (1979) 791-798] demonstrated that the visual flicker sensitivity was an inverted U-like function of the intensity of different levels of auditory noise from 50 to 90dB (SPL), without concomitant changes in the response bias. The aim of the present study was to extend these observations in the context of the stochastic resonance, a counterintuitive phenomenon in which a particular level of noise enhances the response of a nonlinear system to a weak input signal. We show psychophysical evidence in a yes-no paradigm for the existence of a stochastic resonance-like phenomenon in the auditory-visual interactions. We show that the detection of a weak visual signal was an inverted U-like function of the intensity of different levels of auditory noise. Nevertheless, for a strong visual signal the auditory noise acts in detriment of the ability of visual detection. Our results suggest that auditory noise could be employed in vision rehabilitation interventions in order to improve the detection of weak visual signals.

  15. Stochastic resonance at the periphery of auditory system: A simulation experiment

    NASA Astrophysics Data System (ADS)

    Rimskaya-Korsakova, L. K.

    2004-03-01

    An auditory nerve fiber model is studied. The model includes the formation of the response of the basilar membrane, formation of the receptor potential of the internal hair cell, formation of the synaptic potential of the auditory nerve fiber, and transformation of the synaptic potential into a sequence of spikes. The role of this transformation, as well as the role of changes in the excitability of the fiber after the spike generation in the coding of amplitude-modulated signals is revealed for the cases of signals of medium (i.e., corresponding to the sloping part of the curve representing the mean firing rate of an auditory nerve fiber as a function of the stimulus level) and subthreshold levels. Simulated experiments show that the coding of the envelope of a medium-level amplitude-modulated signal is a dynamic process, which includes fine tuning (adaptation) of the threshold of the auditory nerve fiber to the stimulus level. The coding of the signal envelope is little affected by the slope of the dependence of the mean firing rate on the stimulus level. However, fibers with steep input-output characteristics may exhibit stochastic resonance properties. Owing to these properties, such fibers are capable of reproducing the envelope of a subthreshold modulated signal when weak noise is added to it. Ways are considered for extending the range of subthreshold signal and noise levels within which the envelope of a modulated signal is reproduced (or the phenomenon of stochastic resonance is observed).

  16. Stochastic Resonance Reveals “Pilot Light” Expression in Mammalian Genes

    PubMed Central

    Ptitsyn, Andrey

    2008-01-01

    Background Microarrays are widely used for estimation of expression of thousands of genes in a biological sample. The resolution ability of this method is limited by the background noise. Low expressed genes are detected with insufficient reliability and expression of many genes is never detected at all. Methodology/Principal Findings We have applied the principles of stochastic resonance to detect expression of genes from microarray signals below the background noise level. We report the periodic pattern detected in genes called “Absent” by traditional analysis. The pattern is consistent with expression of the conventionally detected genes and specific to the tissue of origin. This effect is corroborated by the analysis of oscillating gene expression in mouse (M.musculus) and yeast (S. cerevisae). Conclusion/Significance Most genes usually considered silent are in fact expressed at a very low level. Stochastic resonance can be applied to detect changes in expression pattern of low-expressed genes as well as for the validation of the probe performance in microarrays. PMID:18365000

  17. Modeling electromagnetic fields detectability in a HH-like neuronal system: stochastic resonance and window behavior.

    PubMed

    Giannì, Matteo; Liberti, Micaela; Apollonio, Francesca; D'Inzeo, Guglielmo

    2006-02-01

    Noise has already been shown to play a constructive role in neuronal processing and reliability, according to stochastic resonance (SR). Here another issue is addressed, concerning noise role in the detectability of an exogenous signal, here representing an electromagnetic (EM) field. A Hodgkin-Huxley like neuronal model describing a myelinated nerve fiber is proposed and validated, excited with a suprathreshold stimulation. EM field is introduced as an additive voltage input and its detectability in neuronal response is evaluated in terms of the output signal-to-noise ratio. Noise intensities maximizing spiking activity coherence with the exogenous EM signal are clearly shown, indicating a stochastic resonant behavior, strictly connected to the model frequency sensitivity. In this study SR exhibits a window of occurrence in the values of field frequency and intensity, which is a kind of effect long reported in bioelectromagnetic experimental studies. The spatial distribution of the modeled structure also allows to investigate possible effects on action potentials saltatory propagation, which results to be reliable and robust over the presence of an exogenous EM field and biological noise. The proposed approach can be seen as assessing biophysical bases of medical applications funded on electric and magnetic stimulation where the role of noise as a cooperative factor has recently gained growing attention.

  18. Malignant Vestibular Schwannoma

    PubMed Central

    Gruber, B.; Petchenik, L.; Williams, M.; Thomas, C.; Luken, M.G.

    1994-01-01

    A 61-year-old woman underwent a translabyrinthine resection of a right intracanulicular acoustic neuroma, which had been detected in the work-up of sudden hearing loss. At the time of surgery, the tumor was roughly twice as large as indicated by the magnetic resonance scan taken only 2 months previously. The tumor eroded the vertical and transverse crests and extended well into the cerebellopontine angle. It was impossible to distinguish the facial nerve proximal to the geniculate ganglion. All visible tumor was resected, along with the facial nerve. Histological evaluation showed a highly cellular tumor, with many mitoses and areas of necrosis, meeting the criteria for malignant schwannoma. The patient has no stigmata of neurofibromatosis, and has no known relatives with that condition. This case is only the fourth reported of a malignant vestibular schwannoma. The relationships between vestibular schwannoma, neurofibromatosis, and malignancy are discussed. ImagesFigure 2Figure 3Figure 4Figure 5Figure 6 PMID:17171176

  19. Litchi freshness rapid non-destructive evaluating method using electronic nose and non-linear dynamics stochastic resonance model.

    PubMed

    Ying, Xiaoguo; Liu, Wei; Hui, Guohua

    2015-01-01

    In this paper, litchi freshness rapid non-destructive evaluating method using electronic nose (e-nose) and non-linear stochastic resonance (SR) was proposed. EN responses to litchi samples were continuously detected for 6 d Principal component analysis (PCA) and non-linear stochastic resonance (SR) methods were utilized to analyze EN detection data. PCA method could not totally discriminate litchi samples, while SR signal-to-noise ratio (SNR) eigen spectrum successfully discriminated all litchi samples. Litchi freshness predictive model developed using SNR eigen values shows high predictive accuracy with regression coefficients R(2) = 0 .99396.

  20. Multi-stable stochastic resonance and its application research on mechanical fault diagnosis

    NASA Astrophysics Data System (ADS)

    Li, Jimeng; Chen, Xuefeng; He, Zhengjia

    2013-10-01

    It is difficult to extract the fault features of a rotating machine via vibration analysis due to interference from background noise. Stochastic resonance (SR), used as a method of utilising noise to amplify weak signals in nonlinear dynamical systems, can detect weak signals overwhelmed in the noise. However, the detection effect of current SR methods is still unsatisfactory. To further increase the output signal-to-noise ratio (SNR) and improve the detection effect of SR, the present study proposes an improved SR method with a multi-stable model for identifying the defect-induced rotating machine faults by analysing the influence relationship between the resonance model and the resonance effect. Due to the structural characteristics of three potential wells and two barriers, the proposed resonance model can not only further amplify weak signals, but also convert into a monostable model, a bistable model or a tristable model. This result is achieved by adjusting system parameters and thus obtaining a better matching of the input signals and resonance models. Therefore, the multi-stable SR method, combined with the characteristics of the multi-stable model, can both increase the output SNR and improve the detection effect and also detect the low SNR signals and enhance the processing capability of SR for weak signals. Finally, the proposed method is applied to a gearbox fault diagnosis in a rolling mill in which two local faults located in the big gear and the pinion, respectively, are found successfully. It can be concluded that multi-stable SR method has practical value in engineering. The influence relationship between a resonance model and SR is analysed. An improved SR method with a multi-stable model is presented. The signal processing performance of multi-stable SR is analysed comparatively. Simulation and application show the validity and superiority of multi-stable SR.

  1. Pacemaker-driven stochastic resonance on diffusive and complex networks of bistable oscillators

    NASA Astrophysics Data System (ADS)

    Perc, Matjaž; Gosak, Marko

    2008-05-01

    We study the phenomenon of stochastic resonance on diffusive, small-world and scale-free networks consisting of bistable overdamped oscillators. Important thereby is the fact that the external subthreshold periodic forcing is introduced only to a single oscillator of the network. Hence, the forcing acts as a pacemaker trying to impose its rhythm on the whole network through the unit to which it is introduced. Without the addition of additive spatiotemporal noise, however, the whole network, including the unit that is directly exposed to the pacemaker, remains trapped forever in one of the two stable steady states of the local dynamics. We show that the correlation between the frequency of subthreshold pacemaker activity and the response of the network is resonantly dependent on the intensity of additive noise. The reported pacemaker-driven stochastic resonance depends most significantly on the coupling strength and the underlying network structure. Namely, the outreach of the pacemaker obeys the classic diffusion law in the case of nearest-neighbor interactions, thus being proportional to the square root of the coupling strength, whereas it becomes superdiffusive by an appropriate small-world or scale-free topology of the interaction network. In particular, the scale-free topology is identified as being optimal for the dissemination of localized rhythmic activity across the whole network. Also, we show that the ratio between the clustering coefficient and the characteristic path length is the crucial quantity defining the ability of a small-world network to facilitate the outreach of the pacemaker-emitted subthreshold rhythm. We additionally confirm these findings by using the FitzHugh-Nagumo excitable system as an alternative to the bistable overdamped oscillator.

  2. Resonant excitation of the magnetosphere by stochastic and unsteady hydromagnetic waves

    SciTech Connect

    Mazur, V. A.

    2011-05-15

    The effect of the magnetospheric MHD cavity on the excitation of the magnetosphere by stochastic and unsteady hydromagnetic waves incident from the solar wind is investigated theoretically by using a one-dimensional nonuniform model of the medium. It is shown that most of the energy of stochastic waves is reflected from the magnetopause and that the only waves that penetrate into the magnetosphere are those with frequencies in narrow spectral ranges near the eigenfrequencies of the cavity. These waves lead to steadystate excitation of the eigenmodes of the cavity, the energy of which is determined by the spectral density of the energy flux of the incident waves at the corresponding eigenfrequencies. The energy of the eigenmodes penetrates through the opacity barrier in the vicinity of the Alfven resonance points (each corresponding to a particular mode), where the perturbation amplitude is sharply amplified, so the total energy localized close to the Alfven resonance point is much higher than the total energy of the corresponding eigenmode. In the vicinities, the perturbation energy is dissipated by the finite conductivity of the ionosphere, the dissipation power being equal to the energy flux of the incident waves that penetrates into the magnetosphere. The case of unsteady waves is analyzed by considering a wave pulse as an example. It is shown that most of the energy of the wave pulse is reflected from the magnetopause. The portion of the incident perturbation that penetrates into the magnetosphere leads to unsteady excitation of the eigenmodes of the magnetospheric cavity, which are then slowly damped because part of the energy of the cavity is emitted through the magnetopause back to the solar wind while the other part penetrates into the vicinities of the Alfven resonance points. In the vicinities, the perturbation is an Alfven wave standing between magnetically conjugate ionospheres and its energy is dissipated by the finite conductivity of the ionosphere at

  3. Balance (or Vestibular) Rehabilitation

    MedlinePlus

    ... the Public / Hearing and Balance Balance (or Vestibular) Rehabilitation Audiologic (hearing), balance, and medical diagnostic tests help ... whether you are a candidate for vestibular (balance) rehabilitation. Vestibular rehabilitation is an individualized balance retraining exercise ...

  4. Compton harmonic resonances, stochastic instabilities, quasilinear diffusion, and collisionless damping with ultra-high intensity laser waves

    SciTech Connect

    Rax, J.M.

    1992-04-01

    The dynamics of electrons in two-dimensional, linearly or circularly polarized, ultra-high intensity (above 10{sup 18}W/cm{sup 2}) laser waves, is investigated. The Compton harmonic resonances are identified as the source of various stochastic instabilities. Both Arnold diffusion and resonance overlap are considered. The quasilinear kinetic equation, describing the evolution of the electron distribution function, is derived, and the associated collisionless damping coefficient is calculated. The implications of these new processes are considered and discussed.

  5. 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.; Wood, S.; Bergquist, F.; Seidler, R. D.; Bloomberg, J. J.

    2014-01-01

    Crewmember adapted to the microgravity state may need to egress the vehicle within a few minutes for safety and operational reasons after gravitational transitions. The transition from one sensorimotor state to another consists of two main mechanisms: strategic and plastic-adaptive and have been demonstrated in astronauts returning after long duration space flight. Strategic modifications represent "early adaptation" - immediate and transitory changes in control that are employed to deal with short-term changes in the environment. If these modifications are prolonged then plastic-adaptive changes are evoked that modify central nervous system function, automating new behavioral responses. More importantly, this longer term adaptive recovery mechanism was significantly associated with their strategic ability to recover on the first day after return to Earth G. We are developing a method based on stochastic resonance to enhance information transfer by improving the brain's ability to detect vestibular signals (Vestibular Stochastic Resonance, VSR) especially when combined with balance training exercises such as sensorimotor adaptability (SA) training for rapid improvement in functional skill, for standing and mobility. This countermeasure to improve detection of vestibular signals is a stimulus delivery system that is wearable/portable providing low imperceptible levels of white noise based binaural bipolar electrical stimulation of the vestibular system (stochastic vestibular stimulation). To determine efficacy of vestibular stimulation on physiological and perceptual responses during otolith-canal conflicts and dynamic perturbations we have conducted a series of studies: We have shown that imperceptible binaural bipolar electrical stimulation of the vestibular system across the mastoids enhances balance performance in the mediolateral (ML) plane while standing on an unstable surface. We have followed up on the previous study showing VSR stimulation improved balance

  6. Stochastic resonance in a tumor-immune system subject to bounded noises and time delay

    NASA Astrophysics Data System (ADS)

    Guo, Wei; Mei, Dong-Cheng

    2014-12-01

    Immunotherapy is one of the most recent approaches in cancer therapy. A mathematical model of tumor-immune interaction, subject to a periodic immunotherapy treatment (imitated by a periodic signal), correlative and bounded stochastic fluctuations and time delays, is investigated by numerical simulations for its signal power amplification (SPA). Within the tailored parameter regime, the synchronous response of tumor growth to the immunotherapy, stochastic resonance (SR), versus both the noises and delays is obtained. The details are as follows (i) the peak values of SPA versus the noise intensity (A) in the proliferation term of tumor cells decrease as the frequency of periodic signal increases, i.e. an increase of the frequency restrains the SR; (ii) an increase of the amplitude of periodic signal restrains the SR versus A, but boosts up the SR versus the noise intensity B in the immune term; (iii) there is an optimum cross-correlated degree between the two bounded noises, at which the system exhibits the strongest SR versus the delay time τα(the reaction time of tumor cell population to their surrounding environment constraints); (iv) upon increasing the delay time τα, double SR versus the delay time τβ (the time taken by both the tumor antigen identification and tumor-stimulated proliferation of effectors) emerges. These results may be helpful for an immunotherapy treatment for the sufferer.

  7. Improvement of Information Transmission of Suprathreshold Input Signal with Stochastic Resonance in Hippocampal CA1 Neuron Network

    NASA Astrophysics Data System (ADS)

    Kawaguchi, Minato; Mino, Hiroyuki; Momose, Keiko; Durand, Dominique M.

    We investigate if and how SR (stochastic resonance) can be shown in the presence of supra-threshold signals (SSR) in physiologically realistic neural networks. The mutual information was maximized at a specific amplitude of noise in larger neural networks, implying SSR.

  8. Improved Detection of Magnetic Signals by a MEMS Sensor Using Stochastic Resonance

    PubMed Central

    Herrera-May, Agustín L.; Tapia, Jesus A.; Domínguez-Nicolás, Saúl M.; Juarez-Aguirre, Raul; Gutierrez-D, Edmundo A.; Flores, Amira; Figueras, Eduard; Manjarrez, Elias

    2014-01-01

    We introduce the behavior of the electrical output response of a magnetic field sensor based on microelectromechanical systems (MEMS) technology under different levels of controlled magnetic noise. We explored whether a particular level of magnetic noise applied on the vicinity of the MEMS sensor can improve the detection of subthreshold magnetic fields. We examined the increase in the signal-to-noise ratio (SNR) of such detected magnetic fields as a function of the magnetic noise intensity. The data disclosed an inverted U-like graph between the SNR and the applied magnetic noise. This finding shows that the application of an intermediate level of noise in the environment of a MEMS magnetic field sensor improves its detection capability of subthreshold signals via the stochastic resonance phenomenon. PMID:25329563

  9. The mean first passage time and stochastic resonance in gene transcriptional system with time delay

    NASA Astrophysics Data System (ADS)

    Feng, Y. L.; Zhu, J.; Zhang, M.; Gao, L. L.; Liu, Y. F.; Dong, J. M.

    2016-04-01

    In this paper, the gene transcriptional dynamics driven by correlated noises are investigated, where the time delay for the synthesis of transcriptional factor is introduced. The effects of the noise correlation strength and time delay on the stationary probability distribution (SPD), the mean first passage time and the stochastic resonance (SR) are analyzed in detail based on the delay Fokker-Planck equation. It is found that both the time delay and noise correlation strength play important roles in the bistable transcriptional system. The effect of the correlation strength reduces but the time delay enhances the mean first passage time (MFPT). Finally, the SR for this gene transcriptional system is found to be enhanced by the time delay.

  10. Improved detection of magnetic signals by a MEMS sensor using stochastic resonance.

    PubMed

    Herrera-May, Agustín L; Tapia, Jesus A; Domínguez-Nicolás, Saúl M; Juarez-Aguirre, Raul; Gutierrez-D, Edmundo A; Flores, Amira; Figueras, Eduard; Manjarrez, Elias

    2014-01-01

    We introduce the behavior of the electrical output response of a magnetic field sensor based on microelectromechanical systems (MEMS) technology under different levels of controlled magnetic noise. We explored whether a particular level of magnetic noise applied on the vicinity of the MEMS sensor can improve the detection of subthreshold magnetic fields. We examined the increase in the signal-to-noise ratio (SNR) of such detected magnetic fields as a function of the magnetic noise intensity. The data disclosed an inverted U-like graph between the SNR and the applied magnetic noise. This finding shows that the application of an intermediate level of noise in the environment of a MEMS magnetic field sensor improves its detection capability of subthreshold signals via the stochastic resonance phenomenon.

  11. Stochastic resonance in a time-delayed bistable system driven by trichotomous noise

    NASA Astrophysics Data System (ADS)

    Zhou, Bingchang; Lin, Dandan

    2017-03-01

    This paper studies the phenomenon of stochastic resonance (SR) in a bistable system with time delay driven by trichotomous noise. Firstly, a method of numerical simulation for trichotomous noise is presented and its accuracy is checked using normalized autocorrelation function. Then the effects of feedback strength and time delay on the system responses and signal-to-noise ratio (SNR) are studied. The results show that negative feedback strength is more beneficial than positive to promote SR. The effect of time delay on SR is related to the value of feedback strength. The influence of the signal amplitude and frequency on SR is also investigated. It is found that large amplitude and small frequency of the signal can promote the occurrence of SR. Finally, the influence of the amplitude and stationary probability of trichotomous noise on SNR are discussed.

  12. Noise-Induced Sensitization of Human Brain: Toward the Neurological Application of Stochastic Resonance

    NASA Astrophysics Data System (ADS)

    Yamamoto, Yoshiharu; Soma, Rika; Hidaka, Ichiro; Nozaki, Daichi; Iso-o, Noriko; Kwak, Shin

    2003-05-01

    In the past decade, it has been recognized that noise can enhance the response of nonlinear systems to weak signals, via a mechanism known as stochastic resonance (SR). Particularly, the concept of SR has generated considerable interest in sensory biology, because it has been shown in several experimental studies that noise can assist neural systems in detecting weak signals which could not be detected in its absence. Recently, we have shown a similar type of noise-induced sensitization of human brain; externally added noise to the brain stem baroreflex centers sensitized their responses in maintaining adequate blood perfusion to the brain itself. Furthermore, the addition of noise has also shown to be useful in compensating for dysfunctions of the baroreflex centers in certain neurological diseases. It is concluded that the statistical physics concept of SR could be useful in sensitizing human brain in health and disease.

  13. Improvement of tactile sensitivity by stochastic resonance effect--applications to surgical grasping forceps.

    PubMed

    Sueda, Yamato; Hattori, Minoru; Sawada, Hiroyuki; Egi, Hiroyuki; Ohdan, Hideki; Ueda, Jun; Tsuji, Toshio; Kurita, Yuichi

    2013-01-01

    This paper reports experimental results on a surgical grasping forceps with a vibration actuator that enhances a tactile perception ability. A short-time exposure of tactile receptors to sub-sensory white-noise vibration is known to improve perception ability. This phenomenon, called stochastic resonance (SR) in the somatosensory system, is expected to enhance the sense of touch when the weak vibration is applied to a fingertip, and thereby improve associated motor skills. A lead zirconate titanate (PZT) actuator was attached on the grip of surgical grasping forceps. A passive sensory test has been conducted for healthy subjects to confirm the efficacy of the device. Statistical significance has been observed when appropriate noise is applied. To investigate the effect of the noise intensity, a summing network of FitzHugh-Nagumo model neurons was built. The simulation results showed that a network with relatively large units can improve the detection capability of the input signal.

  14. Logical stochastic resonance with correlated internal and external noises in a synthetic biological logic block

    NASA Astrophysics Data System (ADS)

    Dari, Anna; Kia, Behnam; Bulsara, Adi R.; Ditto, William L.

    2011-12-01

    Following the advent of synthetic biology, several gene networks have been engineered to emulate digital devices, with the ability to program cells for different applications. In this work, we adapt the concept of logical stochastic resonance to a synthetic gene network derived from a bacteriophage λ. The intriguing results of this study show that it is possible to build a biological logic block that can emulate or switch from the AND to the OR gate functionalities through externally tuning the system parameters. Moreover, this behavior and the robustness of the logic gate are underpinned by the presence of an optimal amount of random fluctuations. We extend our earlier work in this field, by taking into account the effects of correlated external (additive) and internal (multiplicative or state-dependent) noise. Results obtained through analytical calculations as well as numerical simulations are presented.

  15. Controlling of stochastic resonance and noise enhanced stability induced by harmonic noises in a bistable system

    NASA Astrophysics Data System (ADS)

    Wang, Chao-Jie; Long, Fei; Zhang, Pei; Nie, Lin-Ru

    2017-04-01

    Stochastic resonance (SR) and noise enhanced stability (NES) in a bistable system driven by an additive harmonic noise and a multiplicative harmonic noise is investigated. Through numerical simulation, we obtained the power spectrum by the Fourier transformation on time series. The results indicate that (i) for certain values of the parameters of additive harmonic noise Γ, Ω and the noise intensity D, the SR phenomenon occurs. It means we can control the SR phenomenon by modulating the parameters of harmonic noise; (ii) the NES phenomenon occurs at certain values of the parameters of multiplicative harmonic noise Γ, Ω and the multiplicative noise intensity Q. Most important, the NES phenomenon can also be controlled by modulating the parameters of harmonic noise.

  16. The Recovery of Weak Impulsive Signals Based on Stochastic Resonance and Moving Least Squares Fitting

    PubMed Central

    Jiang, Kuosheng.; Xu, Guanghua.; Liang, Lin.; Tao, Tangfei.; Gu, Fengshou.

    2014-01-01

    In this paper a stochastic resonance (SR)-based method for recovering weak impulsive signals is developed for quantitative diagnosis of faults in rotating machinery. It was shown in theory that weak impulsive signals follow the mechanism of SR, but the SR produces a nonlinear distortion of the shape of the impulsive signal. To eliminate the distortion a moving least squares fitting method is introduced to reconstruct the signal from the output of the SR process. This proposed method is verified by comparing its detection results with that of a morphological filter based on both simulated and experimental signals. The experimental results show that the background noise is suppressed effectively and the key features of impulsive signals are reconstructed with a good degree of accuracy, which leads to an accurate diagnosis of faults in roller bearings in a run-to failure test. PMID:25076220

  17. Model for biological communication in a nanofabricated cell-mimic driven by stochastic resonance

    SciTech Connect

    Karig, David K; Siuti, Piro; Dar, Roy D.; Retterer, Scott T; Doktycz, Mitchel John; Simpson, Michael L

    2011-01-01

    Cells offer natural examples of highly efficient networks of nanomachines. Accordingly, both intracellular and intercellular communication mechanisms in nature are looked to as a source of inspiration and instruction for engineered nanocommunication. Harnessing biological functionality in this manner requires an interdisciplinary approach that integrates systems biology, synthetic biology, and nanofabrication. Recent years have seen the amassing of a tremendous wealth of data from the sequencing of new organisms and from high throughput expression experiments. At the same time, a deeper fundamental understanding of individual cell function has been developed, as exemplified by the growth of fields such as noise biology, which seeks to characterize the role of noise in gene expression. The availability of well characterized biological components coupled with a deeper understanding of cell function has led to efforts to engineer both living cells and to create bio-like functionality in non-living substrates in the field of synthetic biology. Here, we present a model system that exemplifies the synergism between these realms of research. We propose a synthetic gene network for operation in a nanofabricated cell mimic array that propagates a biomolecular signal over long distances using the phenomenon of stochastic resonance. Our system consists of a bacterial quorum sensing signal molecule, a bistable genetic switch triggered by this signal, and an array of nanofabricated cell mimic wells that contain the genetic system. An optimal level of noise in the system helps to propagate a time-varying AHL signal over long distances through the array of mimics. This noise level is determined both by the system volume and by the parameters of the genetic network. Our proposed genetically driven stochastic resonance system serves as a testbed for exploring the potential harnessing of gene expression noise to aid in the transmission of a time-varying molecular signal.

  18. Vestibular stimulation by magnetic fields

    PubMed Central

    Ward, Bryan K.; Roberts, Dale C.; Della Santina, Charles C.; Carey, John P.; Zee, David S.

    2015-01-01

    Individuals working next to strong static magnetic fields occasionally report disorientation and vertigo. With the increasing strength of magnetic fields used for magnetic resonance imaging (MRI) studies, these reports have become more common. It was recently learned that humans, mice and zebrafish all demonstrate behaviors consistent with constant peripheral vestibular stimulation while inside a strong, static magnetic field. The proposed mechanism for this effect involves a Lorentz force resulting from the interaction of a strong static magnetic field with naturally occurring ionic currents flowing through the inner ear endolymph into vestibular hair cells. The resulting force within the endolymph is strong enough to displace the lateral semicircular canal cupula, inducing vertigo and the horizontal nystagmus seen in normal mice and in humans. This review explores the evidence for interactions of magnetic fields with the vestibular system. PMID:25735662

  19. Quantitative evaluation on the performance and feature enhancement of stochastic resonance for bearing fault diagnosis

    NASA Astrophysics Data System (ADS)

    Li, Guoying; Li, Jimeng; Wang, Shibin; Chen, Xuefeng

    2016-12-01

    Stochastic resonance (SR) has been widely applied in the field of weak signal detection by virtue of its characteristic of utilizing noise to amplify useful signal instead of eliminating noise in nonlinear dynamical systems. How to quantitatively evaluate the performance of SR, including the enhancement effect and the degree of waveform distortion, and how to accurately extract signal amplitude have become two important issues in the research on SR. In this paper, the signal-to-noise ratio (SNR) of the main component to the residual in the SR output is constructed to quantitatively measure the enhancement effect of the SR method. And two indices are constructed to quantitatively measure the degree of waveform distortion of the SR output, including the correlation coefficient between the main component in the SR output and the original signal, and the zero-crossing ratio. These quantitative indices are combined to provide a comprehensive quantitative index for adaptive parameter selection of the SR method, and eventually the adaptive SR method can be effective in enhancing the weak component hidden in the original signal. Fast Fourier Transform and Fourier Transform (FFT+FT) spectrum correction technology can extract the signal amplitude from the original signal and effectively reduce the difficulty of extracting signal amplitude from the distorted resonance output. The application in vibration analysis for bearing fault diagnosis verifies that the proposed quantitative evaluation method for adaptive SR can effectively detect weak fault feature of the vibration signal during the incipient stage of bearing fault.

  20. Effect of coupling on stochastic resonance and stochastic antiresonance processes in a unidirectionally N-coupled systems in periodic sinusoidal potential

    NASA Astrophysics Data System (ADS)

    Wadop Ngouongo, Y. J.; Djuidjé Kenmoé, G.; Kofané, T. C.

    2017-04-01

    This work presents the characterization of stochastic resonance (SR) and stochastic antiresonance (SAR) in terms of hysteresis loop area (HLA). In connection with SR and SAR phenomena, we study the dynamics of a chain of particles coupled by nonlinear springs in a periodic sinusoidal potential. The dependence of the coupling parameter as well as the system size on SR and SAR is analysed. We consider the role played by the nonlinear coupling on the SR. We show that there is a range of coupling parameter where only SAR is observed, after this range the SR can occur, however, there also exists a range where neither SAR nor SR appear. It is noted that the maximum and the minimum of the average input energy increases with the coupling parameter. Also demonstrate that there exists an optimal value of the number of particles N for which the average input energy of the first particle reaches the saturation.

  1. The vestibular system

    NASA Technical Reports Server (NTRS)

    Graybiel, A.

    1973-01-01

    The end organs, central nervous system connections, and static and dynamic characteristics of the vestibular system are presented. Vestibular servation in man and vestibular side effect prevention from space missions involving artificial gravity generation are also considered. Vestibular models and design criteria for rotating space vehicles are appended.

  2. Components of vestibular cortical function.

    PubMed

    Klingner, Carsten M; Volk, Gerd F; Flatz, Claudia; Brodoehl, Stefan; Dieterich, Marianne; Witte, Otto W; Guntinas-Lichius, Orlando

    2013-01-01

    It is known that the functional response (e.g., nystagmus) to caloric vestibular stimulation is delayed and prolonged compared with the stimulus-response timing of other sensory systems. Imaging studies have used different models to predict cortical responses and to determine the areas of the brain that are involved. These studies have revealed a widespread network of vestibular brain regions. However, there is some disagreement regarding the brain areas involved, which may partly be caused by differences in the models used. This disagreement indicates the possible existence of multiple cortical components with different temporal characteristics that underlie cortical vestibular processing. However, data-driven methods have yet to be used to analyze the underlying hemodynamic components during and after vestibular stimulation. We performed functional magnetic resonance imaging (fMRI) on 12 healthy subjects during caloric stimulation and analyzed these data using a model-free analysis method (ICA). We found seven independent stimulus-induced components that outline a robust pattern of cortical activation and deactivation. These independent components demonstrated significant differences in their time courses. No single-modeled response function was able to cover the entire range of these independent components. The response functions determined in the present study should improve model-based studies investigating vestibular cortical processing.

  3. Weak-signal detection based on the stochastic resonance of bistable Duffing oscillator and its application in incipient fault diagnosis

    NASA Astrophysics Data System (ADS)

    Lai, Zhi-hui; Leng, Yong-gang

    2016-12-01

    Stochastic resonance (SR) is an important approach to detect weak vibration signals from heavy background noise and further realize mechanical incipient fault diagnosis. The stochastic resonance of a bistable Duffing oscillator is limited by strict small-parameter conditions, i.e., SR can only take place under small values of signal parameters (signal amplitude, frequency, and noise intensity). We propose a method to treat the large-parameter SR for this oscillator. The linear amplitude-transformed, time/frequency scale-transformed, and parameter-adjusted methods are presented and used to produce SR for signals with large-amplitude, large-frequency and/or large-intensity noise. Furthermore, we propose the weak-signal detection approach based on large-parameter SR in the oscillator. Finally, we employ two practical examples to demonstrate the feasibility of the proposed approach in incipient fault diagnosis.

  4. Stochastic resonance in the presence or absence of external signal in the continuous stirred tank reactor system

    NASA Astrophysics Data System (ADS)

    Hou, Zhonghuai; Xin, Houwen

    1999-07-01

    A two variable model, which has been proposed to describe a first-order, exothermic, irreversible reaction A→B carried out in a continuous stirred tank reactor (CSTR), is investigated when the control parameter is modulated by random and/or periodic forces. Within the bistable region where a limit cycle and a stable node coexist, stochastic resonance (SR) is observed when both random and periodic modulations are present. In the absence of periodic external signal noise induced coherent oscillations (NICO) appear when the control parameter is randomly modulated near the supercritical Hopf bifurcation point. In addition, the NICO-strength goes through a maximum with the increment of the noise intensity, characteristic for the occurrence of internal signal stochastic resonance (ISSR).

  5. Stochastic resonance in biology. How noise can enhance detection of weak signals and help improve biological information processing.

    PubMed

    Hänggi, Peter

    2002-03-12

    Noise is usually thought of as the enemy of order rather than as a constructive influence. In nonlinear systems that possess some sort of threshold, random noise plays a beneficial role in enhancing the detection of weak information-carrying signals. This phenomenon, termed stochastic resonance, does find useful applications in physical, biological, and biomedical contexts. Certain biological systems may even use this effect for optimizing function and behavior.

  6. Electrical noise modulates perception of electrical pulses in humans: sensation enhancement via stochastic resonance.

    PubMed

    Iliopoulos, Fivos; Nierhaus, Till; Villringer, Arno

    2014-03-01

    Although noise is usually considered to be harmful for signal detection and information transmission, stochastic resonance (SR) describes the counterintuitive phenomenon of noise enhancing the detection and transmission of weak input signals. In mammalian sensory systems, SR-related phenomena may arise both in the peripheral and the central nervous system. Here, we investigate behavioral SR effects of subliminal electrical noise stimulation on the perception of somatosensory stimuli in humans. We compare the likelihood to detect near-threshold pulses of different intensities applied on the left index finger during presence vs. absence of subliminal noise on the same or an adjacent finger. We show that (low-pass) noise can enhance signal detection when applied on the same finger. This enhancement is strong for near-threshold pulses below the 50% detection threshold and becomes stronger when near-threshold pulses are applied as brief trains. The effect reverses at pulse intensities above threshold, especially when noise is replaced by subliminal sinusoidal stimulation, arguing for a peripheral direct current addition. Unfiltered noise applied on longer pulses enhances detection of all pulse intensities. Noise applied to an adjacent finger has two opposing effects: an inhibiting effect (presumably due to lateral inhibition) and an enhancing effect (most likely due to SR in the central nervous system). In summary, we demonstrate that subliminal noise can significantly modulate detection performance of near-threshold stimuli. Our results indicate SR effects in the peripheral and central nervous system.

  7. Stochastic resonance in the spinal cord and somatosensory cortex of the cat

    NASA Astrophysics Data System (ADS)

    Manjarrez, Elias; Rojas-Piloni, Gerardo; Perez, Hugo; Mendez, Ignacio; Hernandez-Paxtian, Zulma; Flores, Amira

    2003-05-01

    The aim of this study was to demonstrate the occurrence of stochastic resonance (SR) in spinal and cortical potentials elicited by periodic tactile stimuli in the anaesthetised cat. The periodic tactile stimuli were applied on the central pad of the hindpaw and the noisy tactile stimuli on the glabrous skin of the third hindpaw digit. This protocol allowed that the signal and noise were mixed not in the skin but in the somatosensory regions of the central nervous system. The results show that a particular level of tactile noise can increase the amplitude of the spinal and cortical potentials elicited by periodic tactile stimuli. The topographical distribution of evoked potentials indicates that the effects of noise were spatially restricted. All cats showed distinct SR behavior at the spinal and cortical stages of the sensory encoding. Such SR was abolished in the cortical but not in the spinal recording after the sectioning of the ascending pathways. This suggests that the spinal neurones may also contribute to the SR observed at the cortical level. The present study documents the first evidence that the SR phenomenon occurs in the spinal and cortical somatosensory system itself and not only in the peripheral sensory receptors.

  8. Stochastic Resonance in an Underdamped System with Pinning Potential for Weak Signal Detection

    PubMed Central

    Zhang, Haibin; He, Qingbo; Kong, Fanrang

    2015-01-01

    Stochastic resonance (SR) has been proved to be an effective approach for weak sensor signal detection. This study presents a new weak signal detection method based on a SR in an underdamped system, which consists of a pinning potential model. The model was firstly discovered from magnetic domain wall (DW) in ferromagnetic strips. We analyze the principle of the proposed underdamped pinning SR (UPSR) system, the detailed numerical simulation and system performance. We also propose the strategy of selecting the proper damping factor and other system parameters to match a weak signal, input noise and to generate the highest output signal-to-noise ratio (SNR). Finally, we have verified its effectiveness with both simulated and experimental input signals. Results indicate that the UPSR performs better in weak signal detection than the conventional SR (CSR) with merits of higher output SNR, better anti-noise and frequency response capability. Besides, the system can be designed accurately and efficiently owing to the sensibility of parameters and potential diversity. The features also weaken the limitation of small parameters on SR system. PMID:26343662

  9. Theory of Stochastic Dipolar Recoupling in Solid State Nuclear Magnetic Resonance

    PubMed Central

    Tycko, Robert

    2008-01-01

    Dipolar recoupling techniques in solid state nuclear magnetic resonance (NMR) consist of radio-frequency (rf) pulse sequences applied in synchrony with magic-angle spinning (MAS) that create non-zero average magnetic dipole-dipole couplings under MAS. Stochastic dipolar recoupling (SDR) is a variant in which randomly chosen rf carrier frequency offsets are introduced to cause random phase modulations of individual pairwise couplings in the dipolar spin Hamiltonian. Several aspects of SDR are investigated through analytical theory and numerical simulations: (1) An analytical expression for the evolution of nuclear spin polarization under SDR in a two-spin system is derived and verified through simulations, which show a continuous evolution from coherent, oscillatory polarization exchange to incoherent, exponential approach to equilibrium as the range of random carrier offsets (controlled by a parameter fmax) increases; (2) In a many-spin system, polarization transfers under SDR are shown to be described accurately by a rate matrix in the limit of large fmax, with pairwise transfer rates that are proportional to the inverse sixth power of pairwise internuclear distances; (3) Quantum mechanical interferences among non-commuting pairwise dipole-dipole couplings, which are a complicating factor in solid state NMR studies of molecular structures by traditional dipolar recoupling methods, are shown to be absent from SDR data in the limit of large fmax, provided that coupled nuclei have distinct NMR chemical shifts. PMID:18085769

  10. Parameter allocation of parallel array bistable stochastic resonance and its application in communication systems

    NASA Astrophysics Data System (ADS)

    Liu, Jian; Wang, You-Guo; Zhai, Qi-Qing; Liu, Jin

    2016-10-01

    In this paper, we propose a parameter allocation scheme in a parallel array bistable stochastic resonance-based communication system (P-BSR-CS) to improve the performance of weak binary pulse amplitude modulated (BPAM) signal transmissions. The optimal parameter allocation policy of the P-BSR-CS is provided to minimize the bit error rate (BER) and maximize the channel capacity (CC) under the adiabatic approximation condition. On this basis, we further derive the best parameter selection theorem in realistic communication scenarios via variable transformation. Specifically, the P-BSR structure design not only brings the robustness of parameter selection optimization, where the optimal parameter pair is not fixed but variable in quite a wide range, but also produces outstanding system performance. Theoretical analysis and simulation results indicate that in the P-BSR-CS the proposed parameter allocation scheme yields considerable performance improvement, particularly in very low signal-to-noise ratio (SNR) environments. Project supported by the National Natural Science Foundation of China (Grant No. 61179027), the Qinglan Project of Jiangsu Province of China (Grant No. QL06212006), and the University Postgraduate Research and Innovation Project of Jiangsu Province (Grant Nos. KYLX15_0829, KYLX15_0831).

  11. Stochastic resonance subject to multiplicative and additive noise: The influence of potential asymmetries

    NASA Astrophysics Data System (ADS)

    Qiao, Zijian; Lei, Yaguo; Lin, Jing; Niu, Shantao

    2016-11-01

    The influence of potential asymmetries on stochastic resonance (SR) subject to both multiplicative and additive noise is studied by using two-state theory, where three types of asymmetries are introduced in double-well potential by varying the depth, the width, and both the depth and the width of the left well alone. The characteristics of SR in the asymmetric cases are different from symmetric ones, where asymmetry has a strong influence on output signal-to-noise ratio (SNR) and optimal noise intensity. Even optimal noise intensity is also associated with the steepness of the potential-barrier wall, which is generally ignored. Moreover, the largest SNR in asymmetric SR is found to be relatively larger than the symmetric one, which also closely depends on noise intensity ratio. In addition, a moderate cross-correlation intensity between two noises is good for improving the output SNR. More interestingly, a double SR phenomenon is observed in certain cases for two correlated noises, whereas it disappears for two independent noises. The above clues are helpful in achieving weak signal detection under heavy background noise.

  12. Noise Improves Visual Motion Discrimination via a Stochastic Resonance-Like Phenomenon

    PubMed Central

    Treviño, Mario; De la Torre-Valdovinos, Braniff; Manjarrez, Elias

    2016-01-01

    The stochastic resonance (SR) is a phenomenon in which adding a moderate amount of noise can improve the signal-to-noise ratio and performance of non-linear systems. SR occurs in all sensory modalities including the visual system in which noise can enhance contrast detection sensitivity and the perception of ambiguous figures embedded in static scenes. Here, we explored how adding background white pixel-noise to a random dot motion (RDM) stimulus produced changes in visual motion discrimination in healthy human adults. We found that, although the average reaction times (RTs) remained constant, an intermediate level of noise improved the subjects’ ability to discriminate motion direction in the RDM task. The psychophysical responses followed an inverted U-like function of the input noise, whereas the incorrect responses with short RTs did not exhibit such modulation by external noise. Moreover, by applying stimulus and noisy signals to different eyes, we found that the SR phenomenon occurred presumably in the primary visual cortex, where these two signals first converge. Our results suggest that a SR-like phenomenon mediates the improvement of visual motion perception in the RDM task. PMID:27932960

  13. Logic signals driven stochastic resonance in bistable dynamics subjected to 1/f noise floor

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Song, A. G.; He, J.

    2011-03-01

    In the presence of 1/ f β noise, we investigate the logical stochastic resonance (LSR) in an asymmetric bistable model driven by various cycling combinations of two logic inputs. The probability of correct logic outputs is calculated according to true table of logic relationships. Two major results are presented. Firstly, it is shown that the LSR effect can be obtained by changing noise strength. Over entire range of noise variance, white noise can be considered to be better than 1/ f noise or 1/ f 2 noise to obtain clean logic operation. At a smaller noise level, 1/ f noise can realize higher output probability than white noise or 1/ f 2 noise. In the sense, 1/ f noise can be considered to be better than white noise or 1/ f 2. On the other hand, the correct probability can evolves nonmonotonically as noise exponent β increases, and a kind of SR-like effect can be obtained as a result of β. At certain intermediate noise variance, the output probability is able to attain its minimum at β = 1. It is also shown that actually some finite β sometime can be better than β = 0 at small range of noise variance. The study might provide some potential complement to LSR effect in the presence of 1/ f β noise.

  14. Sucrose quantitative and qualitative analysis from tastant mixtures based on Cu foam electrode and stochastic resonance.

    PubMed

    Hui, Guohua; Zhang, Jianfeng; Li, Jian; Zheng, Le

    2016-04-15

    Quantitative and qualitative determination of sucrose from complex tastant mixtures using Cu foam electrode was investigated in this study. Cu foam was prepared and its three-dimensional (3-D) mesh structure was characterized by scanning electron microscopy (SEM). Cu foam was utilized as working electrode in three-electrode electrochemical system. Cyclic voltammetry (CV) scanning results exhibited the oxidation procedure of sucrose on Cu foam electrode. Amperometric i-t scanning results indicated that Cu foam electrode selectively responded to sucrose from four tastant mixtures with low limit of detection (LOD) of 35.34 μM, 49.85 μM, 45.89 μM, and 26.81 μM, respectively. The existence of quinine, NaCl, citric acid (CA) and their mixtures had no effect on sucrose detection. Furthermore, mixtures containing different tastants could be discriminated by non-linear double-layered cascaded series stochastic resonance (DCSSR) output signal-to-noise ratio (SNR) eigen peak parameters of CV measurement data. The proposed method provides a promising way for sweetener analysis of commercial food.

  15. Rotating machine fault diagnosis through enhanced stochastic resonance by full-wave signal construction

    NASA Astrophysics Data System (ADS)

    Lu, Siliang; He, Qingbo; Zhang, Haibin; Kong, Fanrang

    2017-02-01

    This study proposes a full-wave signal construction (FSC) strategy for enhancing rotating machine fault diagnosis by exploiting stochastic resonance (SR). The FSC strategy is utilized to transform a half-wave signal (e.g., an envelope signal) into a full-wave one by conducting a Mirror-Cycle-Add (MCA) operation. The constructed full-wave signal evenly modulates the bistable potential and makes the potential tilt back and forth smoothly. This effect provides the equivalent transition probabilities of particle bounce between the two potential wells. A stable SR output signal with better periodicity, which is beneficial to periodic signal detection, can be obtained. In addition, the MCA operation can improve the input signal-to-noise ratio by enhancing the periodic component while attenuating the noise components. These two advantages make the proposed FSCSR method surpass the traditional SR method in fault signal processing. Performance evaluation is conducted by numerical analysis and experimental verification. The proposed MCA-based FSC strategy has the potential to be a universal signal pre-processing technique. Moreover, the proposed FSCSR method can be used in rotating machine fault diagnosis and other areas related to weak signal detection.

  16. An adaptive unsaturated bistable stochastic resonance method and its application in mechanical fault diagnosis

    NASA Astrophysics Data System (ADS)

    Qiao, Zijian; Lei, Yaguo; Lin, Jing; Jia, Feng

    2017-02-01

    In mechanical fault diagnosis, most traditional methods for signal processing attempt to suppress or cancel noise imbedded in vibration signals for extracting weak fault characteristics, whereas stochastic resonance (SR), as a potential tool for signal processing, is able to utilize the noise to enhance fault characteristics. The classical bistable SR (CBSR), as one of the most widely used SR methods, however, has the disadvantage of inherent output saturation. The output saturation not only reduces the output signal-to-noise ratio (SNR) but also limits the enhancement capability for fault characteristics. To overcome this shortcoming, a novel method is proposed to extract the fault characteristics, where a piecewise bistable potential model is established. Simulated signals are used to illustrate the effectiveness of the proposed method, and the results show that the method is able to extract weak fault characteristics and has good enhancement performance and anti-noise capability. Finally, the method is applied to fault diagnosis of bearings and planetary gearboxes, respectively. The diagnosis results demonstrate that the proposed method can obtain larger output SNR, higher spectrum peaks at fault characteristic frequencies and therefore larger recognizable degree than the CBSR method.

  17. Novel synthetic index-based adaptive stochastic resonance method and its application in bearing fault diagnosis

    NASA Astrophysics Data System (ADS)

    Zhou, Peng; Lu, Siliang; Liu, Fang; Liu, Yongbin; Li, Guihua; Zhao, Jiwen

    2017-03-01

    Stochastic resonance (SR), which is characterized by the fact that proper noise can be utilized to enhance weak periodic signals, has been widely applied in weak signal detection. SR is a nonlinear parameterized filter, and the output signal relies on the system parameters for the deterministic input signal. The most commonly used index for parameter tuning in the SR procedure is the signal-to-noise ratio (SNR). However, using the SNR index to evaluate the denoising effect of SR quantitatively is insufficient when the target signal frequency cannot be estimated accurately. To address this issue, six different indexes, namely, power spectral kurtosis of the SR output signal, correlation coefficient between the SR output and the original signal, peak SNR, structural similarity, root mean square error, and smoothness, are constructed in this study to measure the SR output quantitatively. These six quantitative indexes are fused into a new synthetic quantitative index (SQI) via a back propagation neural network to guide the adaptive parameter selection of the SR procedure. The index fusion procedure reduces the instability of each index and thus improves the robustness of parameter tuning. In addition, genetic algorithm is utilized to quickly select the optimal SR parameters. The efficiency of bearing fault diagnosis is thus further improved. The effectiveness and efficiency of the proposed SQI-based adaptive SR method for bearing fault diagnosis are verified through numerical and experiment analyses.

  18. Adaptive stochastic resonance method for impact signal detection based on sliding window

    NASA Astrophysics Data System (ADS)

    Li, Jimeng; Chen, Xuefeng; He, Zhengjia

    2013-04-01

    Aiming at solving the existing sharp problems in impact signal detection by using stochastic resonance (SR) in the fault diagnosis of rotating machinery, such as the measurement index selection of SR and the detection of impact signal with different impact amplitudes, the present study proposes an adaptive SR method for impact signal detection based on sliding window by analyzing the SR characteristics of impact signal. This method can not only achieve the optimal selection of system parameters by means of weighted kurtosis index constructed through using kurtosis index and correlation coefficient, but also achieve the detection of weak impact signal through the algorithm of data segmentation based on sliding window, even though the differences between different impact amplitudes are great. The algorithm flow of adaptive SR method is given and effectiveness of the method has been verified by the contrastive results between the proposed method and the traditional SR method of simulation experiments. Finally, the proposed method has been applied to a gearbox fault diagnosis in a hot strip finishing mill in which two local faults located on the pinion are obtained successfully. Therefore, it can be concluded that the proposed method is of great practical value in engineering.

  19. Multiscale noise tuning of stochastic resonance for enhanced fault diagnosis in rotating machines

    NASA Astrophysics Data System (ADS)

    He, Qingbo; Wang, Jun; Liu, Yongbin; Dai, Daoyi; Kong, Fanrang

    2012-04-01

    The interference from background noise makes it difficult to identify incipient faults of a rotating machine via vibration analysis. By the aid of stochastic resonance (SR), the unavoidable noise can, however, be applied to enhance the signal-to-noise ratio (SNR) of a system output. The classical SR phenomenon requires small parameters, which is not suited for rotating machine fault diagnosis as the defect-induced fault characteristic frequency is usually much higher than 1 Hz. This paper investigates an improved SR approach with parameter tuning for identifying the defect-induced rotating machine faults. A new method of multiscale noise tuning is developed to realize the SR at a fixed noise level by transforming the noise at multiple scales to be distributed in an approximate 1/f form. The proposed SR approach overcomes the limitation of small parameter requirement of the classical SR, and takes advantage of the multiscale noise for an improved SR performance. Thus the method is well-suited for enhancement of rotating machine fault identification when the noise is present at different scales. A new scheme of rotating machine fault diagnosis is hence proposed based on the SR with multiscale noise tuning and has been verified by means of practical vibration signals carrying fault information from bearings and a gearbox. An enhanced performance of the proposed fault diagnosis method is confirmed as compared to several traditional methods.

  20. A new multiscale noise tuning stochastic resonance for enhanced fault diagnosis in wind turbine drivetrains

    NASA Astrophysics Data System (ADS)

    Hu, Bingbing; Li, Bing

    2016-02-01

    It is very difficult to detect weak fault signatures due to the large amount of noise in a wind turbine system. Multiscale noise tuning stochastic resonance (MSTSR) has proved to be an effective way to extract weak signals buried in strong noise. However, the MSTSR method originally based on discrete wavelet transform (DWT) has disadvantages such as shift variance and the aliasing effects in engineering application. In this paper, the dual-tree complex wavelet transform (DTCWT) is introduced into the MSTSR method, which makes it possible to further improve the system output signal-to-noise ratio and the accuracy of fault diagnosis by the merits of DTCWT (nearly shift invariant and reduced aliasing effects). Moreover, this method utilizes the relationship between the two dual-tree wavelet basis functions, instead of matching the single wavelet basis function to the signal being analyzed, which may speed up the signal processing and be employed in on-line engineering monitoring. The proposed method is applied to the analysis of bearing outer ring and shaft coupling vibration signals carrying fault information. The results confirm that the method performs better in extracting the fault features than the original DWT-based MSTSR, the wavelet transform with post spectral analysis, and EMD-based spectral analysis methods.

  1. Gain in stochastic resonance: precise numerics versus linear response theory beyond the two-mode approximation.

    PubMed

    Casado-Pascual, Jesús; Denk, Claus; Gómez-Ordóñez, José; Morillo, Manuel; Hänggi, Peter

    2003-03-01

    In the context of the phenomenon of stochastic resonance (SR), we study the correlation function, the signal-to-noise ratio (SNR), and the ratio of output over input SNR, i.e., the gain, which is associated to the nonlinear response of a bistable system driven by time-periodic forces and white Gaussian noise. These quantifiers for SR are evaluated using the techniques of linear response theory (LRT) beyond the usually employed two-mode approximation scheme. We analytically demonstrate within such an extended LRT description that the gain can indeed not exceed unity. We implement an efficient algorithm, based on work by Greenside and Helfand (detailed in the Appendix), to integrate the driven Langevin equation over a wide range of parameter values. The predictions of LRT are carefully tested against the results obtained from numerical solutions of the corresponding Langevin equation over a wide range of parameter values. We further present an accurate procedure to evaluate the distinct contributions of the coherent and incoherent parts of the correlation function to the SNR and the gain. As a main result we show for subthreshold driving that both the correlation function and the SNR can deviate substantially from the predictions of LRT and yet the gain can be either larger or smaller than unity. In particular, we find that the gain can exceed unity in the strongly nonlinear regime which is characterized by weak noise and very slow multifrequency subthreshold input signals with a small duty cycle. This latter result is in agreement with recent analog simulation results by Gingl et al. [ICNF 2001, edited by G. Bosman (World Scientific, Singapore, 2002), pp. 545-548; Fluct. Noise Lett. 1, L181 (2001)].

  2. Remote vibrotactile noise improves light touch sensation in stroke survivors’ fingertips via stochastic resonance

    PubMed Central

    2013-01-01

    Background and purpose Stroke rehabilitation does not often integrate both sensory and motor recovery. While subthreshold noise was shown to enhance sensory signal detection at the site of noise application, having a noise-generating device at the fingertip to enhance fingertip sensation and potentially enhance dexterity for stroke survivors is impractical, since the device would interfere with object manipulation. This study determined if remote application of subthreshold vibrotactile noise (away from the fingertips) improves fingertip tactile sensation with potential to enhance dexterity for stroke survivors. Methods Index finger and thumb pad sensation was measured for ten stroke survivors with fingertip sensory deficit using the Semmes-Weinstein Monofilament and Two-Point Discrimination Tests. Sensation scores were measured with noise applied at one of three intensities (40%, 60%, 80% of the sensory threshold) to one of four locations of the paretic upper extremity (dorsal hand proximal to the index finger knuckle, dorsal hand proximal to the thumb knuckle, dorsal wrist, volar wrist) in a random order, as well as without noise at beginning (Pre) and end (Post) of the testing session. Results Vibrotactile noise of all intensities and locations instantaneously and significantly improved Monofilament scores of the index fingertip and thumb tip (p < .01). No significant effect of the noise was seen for the Two-Point Discrimination Test scores. Conclusions Remote application of subthreshold (imperceptible) vibrotactile noise at the wrist and dorsal hand instantaneously improved stroke survivors’ light touch sensation, independent of noise location and intensity. Vibrotactile noise at the wrist and dorsal hand may have enhanced the fingertips’ light touch sensation via stochastic resonance and interneuronal connections. While long-term benefits of noise in stroke patients warrants further investigation, this result demonstrates potential that a wearable

  3. Enhanced coding in a cochlear-implant model using additive noise: Aperiodic stochastic resonance with tuning

    NASA Astrophysics Data System (ADS)

    Morse, Robert P.; Roper, Peter

    2000-05-01

    Analog electrical stimulation of the cochlear nerve (the nerve of hearing) by a cochlear implant is an effective method of providing functional hearing to profoundly deaf people. Recent physiological and computational experiments have shown that analog cochlear implants are unlikely to convey certain speech cues by the temporal pattern of evoked nerve discharges. However, these experiments have also shown that the optimal addition of noise to cochlear implant signals can enhance the temporal representation of speech cues [R. P. Morse and E. F. Evans, Nature Medicine 2, 928 (1996)]. We present a simple model to explain this enhancement of temporal representation. Our model derives from a rate equation for the mean threshold-crossing rate of an infinite set of parallel discriminators (level-crossing detectors); a system that well describes the time coding of information by a set of nerve fibers. Our results show that the optimal transfer of information occurs when the threshold level of each discriminator is equal to the root-mean-square noise level. The optimal transfer of information by a cochlear implant is therefore expected to occur when the internal root-mean-square noise level of each stimulated fiber is approximately equal to the nerve threshold. When interpreted within the framework of aperiodic stochastic resonance, our results indicate therefore that for an infinite array of discriminators, a tuning of the noise is still necessary for optimal performance. This is in contrast to previous results [Collins, Chow, and Imhoff, Nature 376, 236 (1995); Chialvo, Longtin, and Müller-Gerking, Phys. Rev. E 55, 1798 (1997)] on arrays of FitzHugh-Nagumo neurons.

  4. Enhanced detection of rolling element bearing fault based on stochastic resonance

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaofei; Hu, Niaoqing; Cheng, Zhe; Hu, Lei

    2012-11-01

    Early bearing faults can generate a series of weak impacts. All the influence factors in measurement may degrade the vibration signal. Currently, bearing fault enhanced detection method based on stochastic resonance(SR) is implemented by expensive computation and demands high sampling rate, which requires high quality software and hardware for fault diagnosis. In order to extract bearing characteristic frequencies component, SR normalized scale transform procedures are presented and a circuit module is designed based on parameter-tuning bistable SR. In the simulation test, discrete and analog sinusoidal signals under heavy noise are enhanced by SR normalized scale transform and circuit module respectively. Two bearing fault enhanced detection strategies are proposed. One is realized by pure computation with normalized scale transform for sampled vibration signal, and the other is carried out by designed SR hardware with circuit module for analog vibration signal directly. The first strategy is flexible for discrete signal processing, and the second strategy demands much lower sampling frequency and less computational cost. The application results of the two strategies on bearing inner race fault detection of a test rig show that the local signal to noise ratio of the characteristic components obtained by the proposed methods are enhanced by about 50% compared with the band pass envelope analysis for the bearing with weaker fault. In addition, helicopter transmission bearing fault detection validates the effectiveness of the enhanced detection strategy with hardware. The combination of SR normalized scale transform and circuit module can meet the need of different application fields or conditions, thus providing a practical scheme for enhanced detection of bearing fault.

  5. [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.

  6. 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.

  7. Stochastic resonance in a piecewise nonlinear model driven by multiplicative non-Gaussian noise and additive white noise

    NASA Astrophysics Data System (ADS)

    Guo, Yongfeng; Shen, Yajun; Tan, Jianguo

    2016-09-01

    The phenomenon of stochastic resonance (SR) in a piecewise nonlinear model driven by a periodic signal and correlated noises for the cases of a multiplicative non-Gaussian noise and an additive Gaussian white noise is investigated. Applying the path integral approach, the unified colored noise approximation and the two-state model theory, the analytical expression of the signal-to-noise ratio (SNR) is derived. It is found that conventional stochastic resonance exists in this system. From numerical computations we obtain that: (i) As a function of the non-Gaussian noise intensity, the SNR is increased when the non-Gaussian noise deviation parameter q is increased. (ii) As a function of the Gaussian noise intensity, the SNR is decreased when q is increased. This demonstrates that the effect of the non-Gaussian noise on SNR is different from that of the Gaussian noise in this system. Moreover, we further discuss the effect of the correlation time of the non-Gaussian noise, cross-correlation strength, the amplitude and frequency of the periodic signal on SR.

  8. Stochastic resonance without an external periodic drive in a simple prey-predator model

    PubMed

    Rai; Singh

    2000-12-01

    We have investigated the effect of noise on a simple prey-predator model where the oscillations are triggered by the internal dynamics of the system without the aid of any external periodic drive. We report the occurrence of stochastic resonancelike behavior in this system, which does not have a threshold or a potential barrier, in the absence of an external drive.

  9. Vestibular Perception following Acute Unilateral Vestibular Lesions

    PubMed Central

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

    2013-01-01

    Little is known about the vestibulo-perceptual (VP) system, particularly after a unilateral vestibular lesion. We investigated vestibulo-ocular (VO) and VP function in 25 patients with vestibular neuritis (VN) acutely (2 days after onset) and after compensation (recovery phase, 10 weeks). Since the effect of VN on reflex and perceptual function may differ at threshold and supra-threshold acceleration levels, we used two stimulus intensities, acceleration steps of 0.5°/s2 and velocity steps of 90°/s (acceleration 180°/s2). We hypothesised that the vestibular lesion or the compensatory processes could dissociate VO and VP function, particularly if the acute vertiginous sensation interferes with the perceptual tasks. Both in acute and recovery phases, VO and VP thresholds increased, particularly during ipsilesional rotations. In signal detection theory this indicates that signals from the healthy and affected side are still fused, but result in asymmetric thresholds due to a lesion-induced bias. The normal pattern whereby VP thresholds are higher than VO thresholds was preserved, indicating that any ‘perceptual noise’ added by the vertigo does not disrupt the cognitive decision-making processes inherent to the perceptual task. Overall, the parallel findings in VO and VP thresholds imply little or no additional cortical processing and suggest that vestibular thresholds essentially reflect the sensitivity of the fused peripheral receptors. In contrast, a significant VO-VP dissociation for supra-threshold stimuli was found. Acutely, time constants and duration of the VO and VP responses were reduced – asymmetrically for VO, as expected, but surprisingly symmetrical for perception. At recovery, VP responses normalised but VO responses remained shortened and asymmetric. Thus, unlike threshold data, supra-threshold responses show considerable VO-VP dissociation indicative of additional, higher-order processing of vestibular signals. We provide evidence of

  10. Combined action of time-delay and colored cross-associated multiplicative and additive noises on stability and stochastic resonance for a stochastic metapopulation system

    NASA Astrophysics Data System (ADS)

    Wang, Kang-Kang; Zong, De-Cai; Wang, Ya-Jun; Li, Sheng-Hong

    2016-05-01

    In this paper, the transition between the stable state of a big density and the extinction state and stochastic resonance (SR) for a time-delayed metapopulation system disturbed by colored cross-correlated noises are investigated. By applying the fast descent method, the small time-delay approximation and McNamara and Wiesenfeld's SR theory, we investigate the impacts of time-delay, the multiplicative, additive noises and colored cross-correlated noise on the SNR and the shift between the two states of the system. Numerical results show that the multiplicative, additive noises and time-delay can all speed up the transition from the stable state to the extinction state, while the correlation noise and its correlation time can slow down the extinction process of the population system. With respect to SNR, the multiplicative noise always weakens the SR effect, while noise correlation time plays a dual role in motivating the SR phenomenon. Meanwhile, time-delay mainly plays a negative role in stimulating the SR phenomenon. Conversely, it could motivate the SR effect to increase the strength of the cross-correlation noise in the SNR-β plot, while the increase of additive noise intensity will firstly excite SR, and then suppress the SR effect.

  11. Stochastic mass-reconstruction: a new technique to reconstruct resonance masses of heavy particles decaying into tau lepton pairs

    SciTech Connect

    Maruyama, Sho

    2015-12-15

    The invariant mass of tau lepton pairs turns out to be smaller than the resonant mass of their mother particle and the invariant mass distribution is stretched wider than the width of the resonant mass as significant fraction of tau lepton momenta are carried away by neutrinos escaping undetected at collider experiments. This paper describes a new approach to reconstruct resonant masses of heavy particles decaying to tau leptons at such experiments. A typical example is a Z or Higgs boson decaying to a tau pair. Although the new technique can be used for each tau lepton separately, I combine two tau leptons to improve mass resolution by requiring the two tau leptons are lined up in a transverse plane. The method is simple to implement and complementary to the collinear approximation technique that works well when tau leptons are not lined up in a transverse plane. The reconstructed mass can be used as another variable in analyses that already use a visible tau pair mass and missing transverse momentum as these variables are not explicitly used in the stochastic mass-reconstruction to select signal-like events.

  12. Förster resonance energy transfer, absorption and emission spectra in multichromophoric systems. III. Exact stochastic path integral evaluation

    SciTech Connect

    Moix, Jeremy M.; Ma, Jian; Cao, Jianshu

    2015-03-07

    A numerically exact path integral treatment of the absorption and emission spectra of open quantum systems is presented that requires only the straightforward solution of a stochastic differential equation. The approach converges rapidly enabling the calculation of spectra of large excitonic systems across the complete range of system parameters and for arbitrary bath spectral densities. With the numerically exact absorption and emission operators, one can also immediately compute energy transfer rates using the multi-chromophoric Förster resonant energy transfer formalism. Benchmark calculations on the emission spectra of two level systems are presented demonstrating the efficacy of the stochastic approach. This is followed by calculations of the energy transfer rates between two weakly coupled dimer systems as a function of temperature and system-bath coupling strength. It is shown that the recently developed hybrid cumulant expansion (see Paper II) is the only perturbative method capable of generating uniformly reliable energy transfer rates and emission spectra across a broad range of system parameters.

  13. Förster resonance energy transfer, absorption and emission spectra in multichromophoric systems. III. Exact stochastic path integral evaluation.

    PubMed

    Moix, Jeremy M; Ma, Jian; Cao, Jianshu

    2015-03-07

    A numerically exact path integral treatment of the absorption and emission spectra of open quantum systems is presented that requires only the straightforward solution of a stochastic differential equation. The approach converges rapidly enabling the calculation of spectra of large excitonic systems across the complete range of system parameters and for arbitrary bath spectral densities. With the numerically exact absorption and emission operators, one can also immediately compute energy transfer rates using the multi-chromophoric Förster resonant energy transfer formalism. Benchmark calculations on the emission spectra of two level systems are presented demonstrating the efficacy of the stochastic approach. This is followed by calculations of the energy transfer rates between two weakly coupled dimer systems as a function of temperature and system-bath coupling strength. It is shown that the recently developed hybrid cumulant expansion (see Paper II) is the only perturbative method capable of generating uniformly reliable energy transfer rates and emission spectra across a broad range of system parameters.

  14. A kinetic and kinematic analysis of the effect of stochastic resonance electrical stimulation and knee sleeve during gait in osteoarthritis of the knee.

    PubMed

    Collins, Amber; Blackburn, Troy; Olcott, Chris; Jordan, Joanne M; Yu, Bing; Weinhold, Paul

    2014-02-01

    Extended use of knee sleeves in populations at risk for knee osteoarthritis progression has shown functional and quality of life benefits; however, additional comprehensive kinematic and kinetic analyses are needed to determine possible physical mechanisms of these benefits which may be due to the sleeve's ability to enhance knee proprioception. A novel means of extending these enhancements may be through stochastic resonance stimulation. Our goal was to determine whether the use of a knee sleeve alone or combined with stochastic resonance electrical stimulation improves knee mechanics in knee osteoarthritis. Gait kinetics and kinematics were assessed in subjects with medial knee osteoarthritis when presented with four conditions: control1, no electrical stimulation/sleeve, 75% threshold stimulation/sleeve, and control2. An increase in knee flexion angle throughout stance and a decrease in flexion moment occurring immediately after initial contact were seen in the stimulation/sleeve and sleeve alone conditions; however, these treatment conditions did not affect the knee adduction angle and internal knee abduction moment during weight acceptance. No differences were found between the sleeve alone and the stochastic resonance with sleeve conditions. A knee sleeve can improve sagittal-plane knee kinematics and kinetics, although adding the current configuration of stochastic resonance did not enhance these effects.

  15. Central vestibular dysfunction in an otorhinolaryngological vestibular unit: incidence and diagnostic strategy.

    PubMed

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

    2014-07-01

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

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

    PubMed Central

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

    2014-01-01

    Introduction Vertigo can be due to a variety of central and peripheral causes. The relative incidence of central causes is underestimated. This may have an important impact of the patients' management and prognosis. Objective The objective of this work is to determine the incidence of central vestibular disorders in patients presenting to a vestibular unit in a tertiary referral academic center. It also aims at determining the best strategy to increase the diagnostic yield of the patients' visit. Methods This is a prospective observational study on 100 consecutive patients with symptoms suggestive of vestibular dysfunction. All patients completed a structured questionnaire and received bedside and vestibular examination and neuroimaging as required. Results There were 69 women and 31 men. Their ages ranged between 28 and 73 (mean 42.48 years). Provisional videonystagmography (VNG) results were: 40% benign paroxysmal positional vertigo (BPPV), 23% suspicious of central causes, 18% undiagnosed, 15% Meniere disease, and 4% vestibular neuronitis. Patients with an unclear diagnosis or central features (41) had magnetic resonance imaging (MRI) and Doppler studies. Combining data from history, VNG, and imaging studies, 23 patients (23%) were diagnosed as having a central vestibular lesion (10 with generalized ischemia/vertebra basilar insufficiency, 4 with multiple sclerosis, 4 with migraine vestibulopathy, 4 with phobic postural vertigo, and 1 with hyperventilation-induced nystagmus). Conclusions Combining a careful history with clinical examination, VNG, MRI, and Doppler studies decreases the number of undiagnosed cases and increases the detection of possible central lesions. PMID:25992098

  17. Trace determination of carbendazim and thiabendazole in drinking water by liquid chromatography and using linear modulated stochastic resonance algorithm.

    PubMed

    Deng, Haishan; Xiang, Bingren; Xie, Shaofei; Zhou, Xiaohua

    2007-01-01

    The following paper addresses an attempt to determine the trace levels of two benzimidazole fungicides (carbendazim, CAS 10605-21-7 and thiabendazole, CAS 148-79-8) in drinking water samples using the newly proposed linear modulated stochastic resonance algorithm. In order to implement an adaptive and intelligent algorithm, a two-step optimization procedure was developed for the parameter selection to give attention to both the signal-to-noise ratio and the peak shape of output signal. How to limit the ranges of the parameters to be searched was discussed in detail. The limits of detection for carbendazim and thiabendazole were improved to 0.012 microg x L(-1) and 0.015 microg x L(-1), respectively. The successful application demonstrated the ability of the algorithm for detecting two or more weak chromatographic peaks simultaneously.

  18. Mean First Passage Time and Stochastic Resonance in a Transcriptional Regulatory System with Non-Gaussian Noise

    NASA Astrophysics Data System (ADS)

    Kang, Yan-Mei; Chen, Xi; Lin, Xu-Dong; Tan, Ning

    The mean first passage time (MFPT) in a phenomenological gene transcriptional regulatory model with non-Gaussian noise is analytically investigated based on the singular perturbation technique. The effect of the non-Gaussian noise on the phenomenon of stochastic resonance (SR) is then disclosed based on a new combination of adiabatic elimination and linear response approximation. Compared with the results in the Gaussian noise case, it is found that bounded non-Gaussian noise inhibits the transition between different concentrations of protein, while heavy-tailed non-Gaussian noise accelerates the transition. It is also found that the optimal noise intensity for SR in the heavy-tailed noise case is smaller, while the optimal noise intensity in the bounded noise case is larger. These observations can be explained by the heavy-tailed noise easing random transitions.

  19. Robust myoelectric signal detection based on stochastic resonance using multiple-surface-electrode array made of carbon nanotube composite paper

    NASA Astrophysics Data System (ADS)

    Shirata, Kento; Inden, Yuki; Kasai, Seiya; Oya, Takahide; Hagiwara, Yosuke; Kaeriyama, Shunichi; Nakamura, Hideyuki

    2016-04-01

    We investigated the robust detection of surface electromyogram (EMG) signals based on the stochastic resonance (SR) phenomenon, in which the response to weak signals is optimized by adding noise, combined with multiple surface electrodes. Flexible carbon nanotube composite paper (CNT-cp) was applied to the surface electrode, which showed good performance that is comparable to that of conventional Ag/AgCl electrodes. The SR-based EMG signal system integrating an 8-Schmitt-trigger network and the multiple-CNT-cp-electrode array successfully detected weak EMG signals even when the subject’s body is in the motion, which was difficult to achieve using the conventional technique. The feasibility of the SR-based EMG detection technique was confirmed by demonstrating its applicability to robot hand control.

  20. Generalized Parameter-Adjusted Stochastic Resonance of Duffing Oscillator and Its Application to Weak-Signal Detection.

    PubMed

    Lai, Zhi-Hui; Leng, Yong-Gang

    2015-08-28

    A two-dimensional Duffing oscillator which can produce stochastic resonance (SR) is studied in this paper. We introduce its SR mechanism and present a generalized parameter-adjusted SR (GPASR) model of this oscillator for the necessity of parameter adjustments. The Kramers rate is chosen as the theoretical basis to establish a judgmental function for judging the occurrence of SR in this model; and to analyze and summarize the parameter-adjusted rules under unmatched signal amplitude, frequency, and/or noise-intensity. Furthermore, we propose the weak-signal detection approach based on this GPASR model. Finally, we employ two practical examples to demonstrate the feasibility of the proposed approach in practical engineering application.

  1. Study of detecting mechanism of carbon nanotubes gas sensor based on multi-stable stochastic resonance model.

    PubMed

    Jingyi, Zhu

    2015-01-01

    The detecting mechanism of carbon nanotubes gas sensor based on multi-stable stochastic resonance (MSR) model was studied in this paper. A numerically stimulating model based on MSR was established. And gas-ionizing experiment by adding electronic white noise to induce 1.65 MHz periodic component in the carbon nanotubes gas sensor was performed. It was found that the signal-to-noise ratio (SNR) spectrum displayed 2 maximal values, which accorded to the change of the broken-line potential function. The experimental results of gas-ionizing experiment demonstrated that periodic component of 1.65 MHz had multiple MSR phenomena, which was in accordance with the numerical stimulation results. In this way, the numerical stimulation method provides an innovative method for the detecting mechanism research of carbon nanotubes gas sensor.

  2. Generalized Parameter-Adjusted Stochastic Resonance of Duffing Oscillator and Its Application to Weak-Signal Detection

    PubMed Central

    Lai, Zhi-Hui; Leng, Yong-Gang

    2015-01-01

    A two-dimensional Duffing oscillator which can produce stochastic resonance (SR) is studied in this paper. We introduce its SR mechanism and present a generalized parameter-adjusted SR (GPASR) model of this oscillator for the necessity of parameter adjustments. The Kramers rate is chosen as the theoretical basis to establish a judgmental function for judging the occurrence of SR in this model; and to analyze and summarize the parameter-adjusted rules under unmatched signal amplitude, frequency, and/or noise-intensity. Furthermore, we propose the weak-signal detection approach based on this GPASR model. Finally, we employ two practical examples to demonstrate the feasibility of the proposed approach in practical engineering application. PMID:26343671

  3. Making Sense of the Body: the Role of Vestibular Signals.

    PubMed

    Lopez, Christophe

    2015-01-01

    The role of the vestibular system in posture and eye movement control has been extensively described. By contrast, how vestibular signals contribute to bodily perceptions is a more recent research area in the field of cognitive neuroscience. In the present review article, I will summarize recent findings showing that vestibular signals play a crucial role in making sense of the body. First, data will be presented showing that vestibular signals contribute to bodily perceptions ranging from low-level bodily perceptions, such as touch, pain, and the processing of the body's metric properties, to higher level bodily perceptions, such as the sense of owning a body, the sense of being located within this body (embodiment), and the anchoring of the visuo-spatial perspective to this body. In the second part of the review article, I will show that vestibular information seems to be crucially involved in the visual perception of biological motion and in the visual perception of human body structure. Reciprocally, observing human bodies in motion influences vestibular self-motion perception, presumably due to sensorimotor resonance between the self and others. I will argue that recent advances in the mapping of the human vestibular cortex afford neuroscientific models of the vestibular contributions to human bodily self-consciousness.

  4. Vestibular rehabilitation outcomes in patients with and without vestibular migraine.

    PubMed

    Vitkovic, Jessica; Winoto, Arimbi; Rance, Gary; Dowell, Richard; Paine, Mark

    2013-12-01

    Vestibular rehabilitation programs do appear to play a beneficial role in the treatment of dizziness in patients with vestibular migraine. Anecdotally, however, patients with vestibular migraine may report persistent significant symptoms at the end of a standard treatment period where other non-migrainous patients are accomplishing their treatment goals. Therefore, the objective of this study was to assess the efficacy of vestibular rehabilitation in patients with vestibular migraine compared to patients with vestibular symptoms without migraine. Thirty-six patients (vestibular migraine = 20, vestibular impairment = 16) with significant daily vestibular symptoms received a nine week customized vestibular rehabilitation program. Each subject attended five therapy appointments occurring at initial, two, five, nine and six months. A range of subjective and physical performance outcome measures were taken at baseline, nine weeks and six months. The vestibular migraine group showed poorer subjective performance at the onset of therapy, which was not reflected in the difference in physical performance between the groups. Both groups benefitted equally from rehabilitation. The same degree of improvement was observed in the migraine group regardless of medication regime. This study has validated vestibular rehabilitation as an effective treatment in dizzy patients both with and without vestibular migraine where the use of medication did not preclude benefit from therapy. However, further research is required to clarify the role of specific vestibular suppressant medications and the scheduling of their use in relation to physical therapy.

  5. A non-perturbative analytic expression of signal amplification factor in stochastic resonance

    NASA Astrophysics Data System (ADS)

    Dhara, Asish Kumar

    2017-04-01

    We put forward a non-perturbative scheme to calculate the response of an overdamped bistable system driven by a Gaussian white noise and perturbed by a weak monochromatic force (signal) analytically. The formalism takes into account infinite number of perturbation terms of a perturbation series with amplitude of the signal as an expansion parameter. The contributions of infinite number of relaxation modes of the stochastic dynamics to the response are also taken into account in this formalism. A closed form analytic expression of the response is obtained. Only the knowledge of the first non-trivial eigenvalue and the lowest eigenfunction of the un-perturbed Fokker-Planck operator are needed to evaluate the response. The response calculated from the derived analytic expression matches fairly well with the numerical results.

  6. Types of Vestibular Disorders

    MedlinePlus

    ... include complications from aging, autoimmune disorders, and allergies. Acoustic Neuroma Acoustic neuroma (also called a vestibular schwannoma) is a ... This nerve is also referred to as the acoustic nerve, hence the name.) As an acoustic neuroma ...

  7. Stochastic approach to diffusion inside the chaotic layer of a resonance.

    PubMed

    Mestre, Martín F; Bazzani, Armando; Cincotta, Pablo M; Giordano, Claudia M

    2014-01-01

    We model chaotic diffusion in a symplectic four-dimensional (4D) map by using the result of a theorem that was developed for stochastically perturbed integrable Hamiltonian systems. We explicitly consider a map defined by a free rotator (FR) coupled to a standard map (SM). We focus on the diffusion process in the action I of the FR, obtaining a seminumerical method to compute the diffusion coefficient. We study two cases corresponding to a thick and a thin chaotic layer in the SM phase space and we discuss a related conjecture stated in the past. In the first case, the numerically computed probability density function for the action I is well interpolated by the solution of a Fokker-Planck (FP) equation, whereas it presents a nonconstant time shift with respect to the concomitant FP solution in the second case suggesting the presence of an anomalous diffusion time scale. The explicit calculation of a diffusion coefficient for a 4D symplectic map can be useful to understand the slow diffusion observed in celestial mechanics and accelerator physics.

  8. Vestibular projections in the human cortex.

    PubMed

    de Waele, C; Baudonnière, P M; Lepecq, J C; Tran Ba Huy, P; Vidal, P P

    2001-12-01

    There is considerable evidence from studies on cats and monkeys that several cortical areas such as area 2v at the tip of the intraparietal sulcus, area 3av in the sulcus centralis, the parietoinsular vestibular cortex adjacent to the posterior insula (PIVC) and area 7 in the inferior parietal lobule are involved in the processing of vestibular information. Microelectrode recordings from these areas have shown that: (1) most of these cortical neurons are connected trisynaptically to the labyrinthine endorgans and (2) they receive converging vestibular, visual and somatosensory inputs. These data suggest that a multimodal cortical system is involved in postural and gaze control. In humans, recent positron emission tomography (PET) scans and functional magnetic resonance imaging (fMRI) studies have largely confirmed these data. However, because of the limited temporal resolution of these two methods, the minimum time of arrival of labyrinthine inputs from the vestibular hair cells to these cortical areas has not yet been determined. In this study, we used the evoked potential method to attempt to answer this question. Due to its excellent temporal resolution, this method is ideal for the investigation of the tri- or polysynaptic nature of the vestibulocortical pathways. Eleven volunteer patients, who underwent a vestibular neurectomy due to intractable Meniere's disease (MD) or acoustic neurinoma resection, were included in this experiment. Patients were anesthetized and the vestibular nerve was electrically stimulated. The evoked potentials were recorded by 30 subcutaneous active electrodes located on the scalp. The brain electrical source imaging (BESA) program (version 2.0, 1995) was used to calculate dipole sources. The latency period for the activation of five distinct cortical zones, including the prefrontal and/or the frontal lobe, the ipsilateral temporoparietal cortex, the anterior portion of the supplementary motor area (SMA) and the contralateral parietal

  9. Neurotransmitters in the vestibular system.

    PubMed

    Balaban, C D

    2016-01-01

    Neuronal networks that are linked to the peripheral vestibular system contribute to gravitoinertial sensation, balance control, eye movement control, and autonomic function. Ascending connections to the limbic system and cerebral cortex are also important for motion perception and threat recognition, and play a role in comorbid balance and anxiety disorders. The vestibular system also shows remarkable plasticity, termed vestibular compensation. Activity in these networks is regulated by an interaction between: (1) intrinsic neurotransmitters of the inner ear, vestibular nerve, and vestibular nuclei; (2) neurotransmitters associated with thalamocortical and limbic pathways that receive projections originating in the vestibular nuclei; and (3) locus coeruleus and raphe (serotonergic and nonserotonergic) projections that influence the latter components. Because the ascending vestibular interoceptive and thalamocortical pathways include networks that influence a broad range of stress responses (endocrine and autonomic), memory consolidation, and cognitive functions, common transmitter substrates provide a basis for understanding features of acute and chronic vestibular disorders.

  10. Inferior vestibular neuritis.

    PubMed

    Kim, Ji-Soo; Kim, Hyo Jung

    2012-08-01

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

  11. Can Electrical Vestibular Noise Be Used for the Treatment of Brain Diseases?

    NASA Astrophysics Data System (ADS)

    Yamamoto, Yoshiharu; Soma, Rika; Struzik, Zbigniew R.; Kwak, Shin

    2005-11-01

    The therapy currently available for the treatment of degenerative neurological diseases is far from satisfactory, and a novel therapeutic strategy, especially for pharmacologically unresponsive patients, would be welcomed. The vestibular nerves are known to influence neuronal circuits in the medullary cardiovascular areas and, through the cerebellar vermis, the basal ganglia and the limbic system. By means of noisy galvanic vestibular stimulation (GVS), it may now be possible to ameliorate blunted responsiveness of degenerated neuronal circuits in the brains of multiple system atrophy (MSA) and/or Parkinson's disease (PD) patients, through a mechanism known as stochastic resonance. We evaluate the effect of 24-hour noisy GVS on long-term heart rate dynamics in seven MSA patients, and on daytime locomotor activity dynamics in twelve patients with either PD or levodopa unresponsive parkinsonism. Short-range heart rate variability and long-range anti-correlation of trunk activity are significantly increased by the noisy GVS compared with sham stimulation, suggestive of improved autonomic and motor responsiveness. The noisy GVS is effective in boosting the neuro-degenerative brains of MSA and/or PD patients, including those unresponsive to standard levodopa therapy.

  12. Vestibular rehabilitation after mild traumatic brain injury with vestibular pathology.

    PubMed

    Gottshall, Kim

    2011-01-01

    Vestibular complaints are the most frequent sequelae of mTBI. Vestibular physical therapy has been established as the most important treatment modality for this group of patients. Nevertheless there is little work objectively documenting the impact of vestibular physical therapy on this group of patients. Studies have been completed in the past examining clinical measures like the GCS on overall recovery pattern after TBI. But outcomes measures specifically aimed at examining the adequacy of vestibular tests to track vestibular recoveryhave remained lacking. Scherer and Schubert reinforced the need for best practice vestibular assessment for formulation of appropriate vestibular physical therapy treatment strategies. Now the application of vestibular testing and rehabilitation in this patient population is needed to provide information on objective outcome measures. Vestibular physical therapy is most effective when applied in a customized fashion. While we and others have developed vestibular physical therapy procedures that are applied in best practices for mTBI vestibular patients, these therapies must be customized for the patient entry level of function and expectation level of recovery. Knowledge of the patient's disability and diagnosis is critical to build the foundation for return to activity, work, or sport.

  13. 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.

  14. Recovery from vestibular ototoxicity

    NASA Technical Reports Server (NTRS)

    Black, F. O.; Gianna-Poulin, C.; Pesznecker, S. C.

    2001-01-01

    OBJECTIVE: Determine whether subjects with documented vestibular ototoxicity recover vestibular function and, if so, investigate the recovery dynamics. STUDY DESIGN: Prospective and retrospective reviews and repeated measures. SETTING: Clinical research and technology center. SUBJECTS: Twenty-eight subjects who received vestibulotoxic medications were followed for at least 12 months after initial treatment. CONTROLS: Our subject sample was compared with a published database of normal individuals. INTERVENTIONS: All 28 subjects received systemically administered medications known to be ototoxic. The subjects' treating physicians controlled medication, dosage, and administration schedules. MAIN OUTCOME MEASURES: Tests of horizontal canal vestibulo-ocular function were performed. Subjects' auditory and vestibular symptoms were recorded. RESULTS: Eleven subjects (39%) showed changes in horizontal canal vestibulo-ocular gain constant (GC) and/or time constant (TC) consistent with vestibular ototoxicity. When tested 1 year after ototoxic drug administration, eight of the nine subjects who experienced ototoxic decrease in GC showed a recovery of GC to normal limits. Only one of the eight subjects who experienced ototoxic decrease in TC showed recovery of TC to within normal limits. Ototoxicity onset and recovery were independent of baseline vestibular function, and ototoxicity onset did not correlate with cumulative dose of ototoxic medication. There was no relationship between subjective symptoms and ototoxicity onset. CONCLUSIONS: Recovery of GC after vestibular ototoxicity is more commonly observed than recovery of TC. Because ototoxic changes developed and continued in an unpredictable time and manner in relation to ototoxic drug administration, we propose that once ototoxic changes in vestibulo-ocular reflex are detected, ototoxic medications should be discontinued as soon as possible.

  15. Stochastic resonance whole body vibration increases perceived muscle relaxation but not cardiovascular activation: A randomized controlled trial

    PubMed Central

    Elfering, Achim; Burger, Christian; Schade, Volker; Radlinger, Lorenz

    2016-01-01

    AIM To investigate the acute effects of stochastic resonance whole body vibration (SR-WBV), including muscle relaxation and cardiovascular activation. METHODS Sixty-four healthy students participated. The participants were randomly assigned to sham SR-WBV training at a low intensity (1.5 Hz) or a verum SR-WBV training at a higher intensity (5 Hz). Systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR) and self-reported muscle relaxation were assessed before and immediately after SR-WBV. RESULTS Two factorial analyses of variance (ANOVA) showed a significant interaction between pre- vs post-SR-WBV measurements and SR-WBV conditions for muscle relaxation in the neck and back [F(1,55) = 3.35, P = 0.048, η2 = 0.07]. Muscle relaxation in the neck and back increased in verum SR-WBV, but not in sham SR-WBV. No significant changes between pre- and post-training levels of SBD, DBD and HR were observed either in sham or verum SR-WBV conditions. With verum SR-WBV, improved muscle relaxation was the most significant in participants who reported the experience of back, neck or shoulder pain more than once a month (P < 0.05). CONCLUSION A single session of SR-WBV increased muscle relaxation in young healthy individuals, while cardiovascular load was low. An increase in musculoskeletal relaxation in the neck and back is a potential mediator of pain reduction in preventive worksite SR-WBV trials. PMID:27900274

  16. Stochastic Resonance Controlled Upregulation of Internal Noise after Hearing Loss as a Putative Cause of Tinnitus-Related Neuronal Hyperactivity

    PubMed Central

    Krauss, Patrick; Tziridis, Konstantin; Metzner, Claus; Schilling, Achim; Hoppe, Ulrich; Schulze, Holger

    2016-01-01

    Subjective tinnitus is generally assumed to be a consequence of hearing loss. In animal studies it has been demonstrated that acoustic trauma induced cochlear damage can lead to behavioral signs of tinnitus. In addition it was shown that noise trauma may lead to deafferentation of cochlear inner hair cells (IHC) even in the absence of elevated hearing thresholds, and it seems conceivable that such hidden hearing loss may be sufficient to cause tinnitus. Numerous studies have indicated that tinnitus is correlated with pathologically increased spontaneous firing rates and hyperactivity of neurons along the auditory pathway. It has been proposed that this hyperactivity is the consequence of a mechanism aiming to compensate for reduced input to the auditory system by increasing central neuronal gain, a mechanism referred to as homeostatic plasticity (HP), thereby maintaining mean firing rates over longer timescales for stabilization of neuronal processing. Here we propose an alternative, new interpretation of tinnitus-related development of neuronal hyperactivity in terms of information theory. In particular, we suggest that stochastic resonance (SR) plays a key role in both short- and long-term plasticity within the auditory system and that SR is the primary cause of neuronal hyperactivity and tinnitus. We argue that following hearing loss, SR serves to lift signals above the increased neuronal thresholds, thereby partly compensating for the hearing loss. In our model, the increased amount of internal noise—which is crucial for SR to work—corresponds to neuronal hyperactivity which subsequently causes neuronal plasticity along the auditory pathway and finally may lead to the development of a phantom percept, i.e., subjective tinnitus. We demonstrate the plausibility of our hypothesis using a computational model and provide exemplary findings in human patients that are consistent with that model. Finally we discuss the observed asymmetry in human tinnitus pitch

  17. An underdamped stochastic resonance method with stable-state matching for incipient fault diagnosis of rolling element bearings

    NASA Astrophysics Data System (ADS)

    Lei, Yaguo; Qiao, Zijian; Xu, Xuefang; Lin, Jing; Niu, Shantao

    2017-09-01

    Most traditional overdamped monostable, bistable and even tristable stochastic resonance (SR) methods have three shortcomings in weak characteristic extraction: (1) their potential structures characterized by single stable-state type are insufficient to match with the complicated and diverse mechanical vibration signals; (2) they vulnerably suffer the interference from multiscale noise and largely depend on the help of highpass filters whose parameters are selected subjectively, probably resulting in false detection; and (3) their rescaling factors are fixed as constants generally, thereby ignoring the synergistic effect among vibration signals, potential structures and rescaling factors. These three shortcomings have limited the enhancement ability of SR. To explore the SR potential, this paper initially investigates the SR in a multistable system by calculating its output spectral amplification, further analyzes its output frequency response numerically, then examines the effect of both damping and rescaling factors on output responses and finally presents a promising underdamped SR method with stable-state matching for incipient bearing fault diagnosis. This method has three advantages: (1) the diversity of stable-state types in a multistable potential makes it easy to match with various vibration signals; (2) the underdamped multistable SR, equivalent to a moving nonlinear bandpass filter that is dependent on the rescaling factors, is able to suppress the multiscale noise; and (3) the synergistic effect among vibration signals, potential structures and rescaling and damping factors is achieved using quantum genetic algorithms whose fitness functions are new weighted signal-to-noise ratio (WSNR) instead of SNR. Therefore, the proposed method is expected to possess good enhancement ability. Simulated and experimental data of rolling element bearings demonstrate its effectiveness. The comparison results show that the proposed method is able to obtain higher

  18. Strong perturbations in nonlinear systems. The case of stochastic-like resonance and its biological relevance from a complex system's perspective

    NASA Astrophysics Data System (ADS)

    Basios, Vasileios

    2016-09-01

    A novel case of probabilistic coupling for hybrid stochastic systems with chaotic components via Markovian switching is presented. We study its stability in the norm, in the sense of Lyapunov and present a quantitative scheme for detection of stochastic stability in the mean. In particular we examine the stability of chaotic dynamical systems in which a representative parameter undergoes a Markovian switching between two values corresponding to two qualitatively different attractors. To this end we employ, as case studies, the behaviour of two representative chaotic systems (the classic Rössler and the Thomas-Rössler models) under the influence of a probabilistic switch which modifies stochastically their parameters. A quantitative measure, based on a Lyapunov function, is proposed which detects regular or irregular motion and regimes of stability. In connection to biologically inspired models (Thomas-Rössler models), where strong fluctuations represent qualitative structural changes, we observe the appearance of stochastic resonance-like phenomena i.e. transitions that lead to orderly behavior when the noise increases. These are attributed to the nonlinear response of the system.

  19. Vestibular Disorders Association

    MedlinePlus

    ... get started on your journey to diagnosis and recovery. VEDA Resource Library Visit VEDA's Resource Library to get more information about your vestibular disorder and download one of VEDA's many short ... the first step toward recovery! Use VEDA's free provider directory to search for ...

  20. 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; Bloomberg, Jacob

    2014-01-01

    Crewmember adapted to the microgravity state may need to egress the vehicle within a few minutes for safety and operational reasons after g-transitions. The transition from one sensorimotor state to another consists of two main mechanisms: strategic and plastic-adaptive and have been demonstrated in astronauts returning after long duration space flight. Strategic modifications represent "early adaptation" -immediate and transitory changes in control that are employed to deal with short-term changes in the environment. If these modifications are prolonged then plastic-adaptive changes are evoked that modify central nervous system function, automating new behavioral responses. More importantly, this longer term adaptive recovery mechanism was significantly associated with their strategic ability to recover on the first day after return to Earth G. We are developing a method based on stochastic resonance (SR) to enhance information transfer by improving the brain's ability to detect vestibular signals especially when combined with balance training exercises for rapid improvement in functional skill, for standing and mobility. The countermeasure to improve post-flight balance and locomotor disturbances is a stimulus delivery system that is wearable/portable providing low imperceptible levels of white noise based binaural bipolar electrical stimulation of the vestibular system (stochastic vestibular stimulation, SVS). The techniques for improving signal detection using SVS may thus provide additional information to improve such strategic abilities and thus help in significantly reducing the number of days required to recover functional performance to preflight levels after long duration space flight. We have conducted a series of studies to document the efficacy of SVS stimulation on balance/locomotion tasks on unstable surfaces and motion tracking tasks during intra-vestibular system conflicts. In an initial study, we showed that SVS improved overall balance

  1. Functional and psychiatric vestibular disorders.

    PubMed

    Staab, J P

    2016-01-01

    Behavioral factors have long been recognized as affecting spatial orientation and balance function. Neuroanatomic and neurophysiologic studies conducted worldwide over the last 30 years have substantially advanced our knowledge about the inherently strong connectivity among threat/anxiety, vestibular, visual, and somatosensory systems in the brain. Clinical investigations have shed greater light on the nature of functional and psychiatric disorders that manifest or magnify vestibular morbidity. Concepts of these syndromes have changed over 150 years. Even their nomenclature has had different meanings in different eras. This chapter will review functional and psychiatric vestibular disorders. Terminology will follow the International Classification of Diseases, 11th edition, beta draft and the International Classification of Vestibular Disorders. Anxiety plays a central role in behavioral vestibular morbidity. Anxiety, traumatic stress, obsessive, and depressive disorders may be primary causes of episodic and chronic vestibular symptoms or secondary complications of other vestibular disorders. These psychiatric illnesses affect 30-50% of patients who consult neurologists or otologists for vestibular symptoms. Coexisting psychiatric disorders adversely affect treatment for patients with structural vestibular diseases, especially when unrecognized. Persistent postural-perceptual dizziness is the leading cause of long-term vestibular disability. Fortunately, pharmacologic, psychotherapeutic, and rehabilitative treatments of these illnesses have improved in recent years.

  2. Is Vestibular Neuritis an Immune Related Vestibular Neuropathy Inducing Vertigo?

    PubMed Central

    Greco, A.; Macri, G. F.; Gallo, A.; Fusconi, M.; De Virgilio, A.; Pagliuca, G.; Marinelli, C.; de Vincentiis, M.

    2014-01-01

    Objectives. To review the current knowledge of the aetiology of vestibular neuritis including viral infections, vascular occlusion, and immunomediated mechanisms and to discuss the pathogenesis with relevance to pharmacotherapy. Systematic Review Methodology. Relevant publications on the aetiology and treatment of vestibular neuritis from 1909 to 2013 were analysed. Results and Conclusions. Vestibular neuritis is the second most common cause of peripheral vestibular vertigo and is due to a sudden unilateral loss of vestibular function. Vestibular neuronitis is a disorder thought to represent the vestibular-nerve equivalent of sudden sensorineural hearing loss. Histopathological studies of patients who died from unrelated clinical problems have demonstrated degeneration of the superior vestibular nerve. The characteristic signs and symptoms include sudden and prolonged vertigo, the absence of auditory symptoms, and the absence of other neurological symptoms. The aetiology and pathogenesis of the condition remain unknown. Proposed theories of causation include viral infections, vascular occlusion, and immunomediated mechanisms. The management of vestibular neuritis involves symptomatic treatment with antivertiginous drugs, causal treatment with corticosteroids, and physical therapy. Antiviral agents did not improve the outcomes. PMID:24741601

  3. Vestibular rehabilitation: rationale and indications.

    PubMed

    Cabrera Kang, Christian M; Tusa, Ronald J

    2013-07-01

    Treatment options of the patient with dizziness include medication, rehabilitation with physical therapy, surgery, counseling, and reassurance. Here the authors discuss vestibular rehabilitation for patients with benign paroxysmal positional vertigo (BPPV), unilateral vestibular loss or hypofunction, and bilateral vestibular loss/hypofunction. They describe the different mechanisms for recovery with vestibular rehabilitation, the exercises that are used, and which ones are best. An exhaustive literature review on clinical outcomes with the best research publications for BPPV, unilateral vestibular loss/hypofunction, and bilateral vestibular loss/hypofunction is presented. For BPPV, the authors also summarize the evidence-based review practice parameters published in Neurology by Fife et al. (2008) and review all relevant articles published since then.

  4. [Vestibular neuritis: treatment and prognosis].

    PubMed

    Reinhard, A; Maire, R

    2013-10-02

    Vestibular neuritis is a sudden unilateral peripheral vestibular deficit of unknown origin without associated hearing loss. It is the second cause of peripheral vertigo after Benign Paroxysmal Positional Vertigo (BPPV). The etiology remains unclear and some treatments are still controversial. The prognosis is good. The differential diagnosis of the disease mainly includes an acute vertigo of central origin. This article summarizes the management and prognosis of vestibular neuritis.

  5. An overview of vestibular rehabilitation.

    PubMed

    Whitney, S L; Alghwiri, A A; Alghadir, A

    2016-01-01

    Data related to the efficacy of vestibular rehabilitation and its evolution as an intervention are provided. Concepts and various treatment strategies are described, with explanations of why people with uncompensated peripheral and central vestibular disorders might improve with rehabilitation. Various tests and measures are described that are commonly used to examine patients and determine their level of ability to participate in their environment. Factors that affect recovery, both positively and negatively, are described in order to better prognosticate recovery. A case utilizing many of the principles discussed is included to provide insight into how to utilize vestibular rehabilitation with a person with an uncompensated peripheral vestibular loss.

  6. Vestibular Function Measurement Devices

    PubMed Central

    Miles, Richard D.; Zapala, David A.

    2015-01-01

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

  7. Vestibular compensation and vestibular rehabilitation. Current concepts and new trends.

    PubMed

    Deveze, A; Bernard-Demanze, L; Xavier, F; Lavieille, J-P; Elziere, M

    2014-01-01

    The aim of this review is to present the current knowledge of the mechanisms underlying the vestibular compensation and demonstrating how the vestibular rehabilitation is conducted to help the recovery of balance function. Vestibular rehabilitation is based on improving the natural phenomenon called vestibular compensation that occurs after acute vestibular disturbance or chronic and gradual misbalance. Central compensation implies three main mechanisms namely adaptation, substitution and habituation. The compensation, aided by the rehabilitation aimed to compensate and/or to correct the underused or misused of the visual, proprioceptive and vestibular inputs involved in the postural control. As the strategy of equilibration is not corrected, the patient is incompletely cured and remains with inappropriate balance control with its significance on the risk of fall and impact on quality of life. The vestibular rehabilitation helps to correct inappropriate strategy of equilibrium or to accelerate a good but slow compensation phenomenon. Nowadays, new tools are more and more employed for the diagnosis of vestibular deficit (that may include various sources of impairment), the assessment of postural deficit, the control of the appropriate strategy as well to facilitate the efficiency of the rehabilitation especially in elderly people.

  8. 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.; Reschke, M. F.; Bloomberg, J. J.; Mulavara, A. P.

    2017-01-01

    ) similar to what astronauts experience during transitions to new gravitational environments. Stochastic electrical stimulation can be applied to the vestibular system through electrodes placed over the mastoid process behind the ears in the binaural configuration resulting in stimulation in the mediolateral (side-to-side) plane. An additional electrode can be placed over the bony landmark of the tip of the c7 spinous process for the double monaural configuration, which will cause stimulation in the anteroposterior (forward-backward) plane. A portable constant current bipolar stimulator with subject isolation was designed and built to deliver the stimulus. The unit is powered using a 3.7 V battery pack and designed to produce currents up to 5 mA. The stimulator, controlled by a Raspberry Pi 3 computer, offers several stimulus signal generation options including a standalone mode, which uses onboard signal files stored on the flash memory card. Stochastic stimulation signals will be generated in 0-30 Hz frequency bandwidth. Stimulation amplitude can be increased incrementally to a maximum amplitude of 5.0 mA (e.g., 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 mA). In control trials, subjects will be experiencing vestibular stimulation with 0-mA current applied through the electrodes. The system will be evaluated at various levels of stimulation and in both the binaural and double monaural electrode configurations. One of the objectives is to identify stimulation levels producing effects most comparable to the post-flight disturbances. This is a pilot study that will set the stage for a larger, more comprehensive study that will investigate wider aspects of post-flight sensorimotor dysfunction and set sensorimotor standards for crew health.

  9. Modulation of human vestibular reflexes with increased postural threat

    PubMed Central

    Horslen, Brian C; Dakin, Christopher J; Inglis, J Timothy; Blouin, Jean-Sébastien; Carpenter, Mark G

    2014-01-01

    Anxiety and arousal have been shown to facilitate human vestibulo-ocular reflexes, presumably through direct neural connections between the vestibular nuclei and emotional processing areas of the brain. However, the effects of anxiety, fear and arousal on balance-relevant vestibular reflexes are currently unknown. The purpose of this study was to manipulate standing height to determine whether anxiety and fear can modulate the direct relationship between vestibular signals and balance reflexes during stance. Stochastic vestibular stimulation (SVS; 2–25 Hz) was used to evoke ground reaction forces (GRF) while subjects stood in both LOW and HIGH surface height conditions. Two separate experiments were conducted to investigate the SVS–GRF relationship, in terms of coupling (coherence and cumulant density) and gain, in the medio-lateral (ML) and antero-posterior (AP) directions. The short- and medium-latency cumulant density peaks were both significantly increased in the ML and AP directions when standing in HIGH, compared to LOW, conditions. Likewise, coherence was statistically greater between 4.3 Hz and 6.7 Hz in the ML, and between 5.5 and 17.7 Hz in the AP direction. When standing in the HIGH condition, the gain of the SVS–GRF relationship was increased 81% in the ML direction, and 231% in the AP direction. The significant increases in coupling and gain observed in both experiments demonstrate that vestibular-evoked balance responses are augmented in states of height-induced postural threat. These data support the possibility that fear or anxiety-mediated changes to balance control are affected by altered central processing of vestibular information. PMID:24973412

  10. Multi-frequency weak signal detection based on wavelet transform and parameter compensation band-pass multi-stable stochastic resonance

    NASA Astrophysics Data System (ADS)

    Han, Dongying; li, Pei; An, Shujun; Shi, Peiming

    2016-03-01

    In actual fault diagnosis, useful information is often submerged in heavy noise, and the feature information is difficult to extract. A novel weak signal detection method aimed at the problem of detecting multi-frequency signals buried under heavy background noise is proposed based on wavelet transform and parameter compensation band-pass multi-stable stochastic resonance (SR). First, the noisy signal is processed by parameter compensation, with the noise and system parameters expanded 10 times to counteract the effect of the damping term. The processed signal is decomposed into multiple signals of different scale frequencies by wavelet transform. Following this, we adjust the size of the scaled signals' amplitudes and reconstruct the signals; the weak signal frequency components are then enhanced by multi-stable stochastic resonance. The enhanced components of the signal are processed through a band-pass filter, leaving the enhanced sections of the signal. The processed signal is analyzed by FFT to achieve detection of the multi-frequency weak signals. The simulation and experimental results show that the proposed method can enhance the signal amplitude, can effectively detect multi-frequency weak signals buried under heavy noise and is valuable and usable for bearing fault signal analysis.

  11. Behavioral aspects of vestibular rehabilitation.

    PubMed

    Staab, Jeffrey P

    2011-01-01

    Behavioral factors are an integral part of the overall morbidity of patients with vertigo, dizziness, and balance disorders. Anxiety, depression, and more importantly, loss of balance confidence and sense of debility and handicap beleaguer patients with acute and chronic vestibular symptoms. Vestibular rehabilitation originated as a physical therapy, but a careful look at its research development and clinical applications show it to be as much, or perhaps more, a behavioral intervention. More patients referred for vestibular rehabilitation require habituation to chronic vestibular symptoms and motion sensitivity than compensation for active peripheral or central vestibular deficits. Vestibular rehabilitation may exert a positive effect on behavioral morbidity, but the benefits are somewhat uneven and do not always correlate with physical improvements. Health anxiety (i.e., excessive worry about the cause and consequences of physical symptoms) is an emerging concept in clinical psychiatry and psychology. It may offer an important key to understanding the debility and handicap experienced by many patients with vestibular symptoms and enhance the ability of vestibular rehabilitation to ameliorate their suffering.

  12. Childhood Vestibular Disorders: A Tutorial

    ERIC Educational Resources Information Center

    Mehta, Zarin; Stakiw, Daria B.

    2004-01-01

    There is a growing body of evidence that childhood disorders affecting the vestibular system, although rare, do exist. Describing symptoms associated with the vestibular mechanism for children may be difficult, resulting in misdiagnosing or under-diagnosing these conditions. The pathophysiology, symptoms, and management options of the more common…

  13. Vestibular blueprint in early vertebrates

    PubMed Central

    Straka, Hans; Baker, Robert

    2013-01-01

    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. PMID:24312016

  14. Role of the Insula and Vestibular System in Patients with Chronic Subjective Dizziness: An fMRI Study Using Sound-Evoked Vestibular Stimulation

    PubMed Central

    Indovina, Iole; Riccelli, Roberta; Chiarella, Giuseppe; Petrolo, Claudio; Augimeri, Antonio; Giofrè, Laura; Lacquaniti, Francesco; Staab, Jeffrey P.; Passamonti, Luca

    2015-01-01

    Chronic subjective dizziness (CSD) is a common vestibular disorder characterized by persistent non-vertiginous dizziness, unsteadiness, and heightened sensitivity to motion stimuli that may last for months to years after events that cause acute vestibular symptoms or disrupt balance. CSD is not associated with abnormalities of basic vestibular or oculomotor reflexes. Rather, it is thought to arise from persistent use of high-threat postural control strategies and greater reliance on visual cues for spatial orientation (i.e., visual dependence), long after triggering events resolve. Anxiety-related personality traits confer vulnerability to CSD. Anomalous interactions between the central vestibular system and neural structures related to anxiety may sustain it. Vestibular- and anxiety-related processes overlap in the brain, particularly in the insula and hippocampus. Alterations in activity and connectivity in these brain regions in response to vestibular stimuli may be the neural basis of CSD. We examined this hypothesis by comparing brain activity from 18 patients with CSD and 18 healthy controls measured by functional magnetic resonance imaging during loud short tone bursts, which are auditory stimuli that evoke robust vestibular responses. Relative to controls, patients with CSD showed reduced activations to sound-evoked vestibular stimulation in the parieto-insular vestibular cortex (PIVC) including the posterior insula, and in the anterior insula, inferior frontal gyrus, hippocampus, and anterior cingulate cortex. Patients with CSD also showed altered connectivity between the anterior insula and PIVC, anterior insula and middle occipital cortex, hippocampus and PIVC, and anterior cingulate cortex and PIVC. We conclude that reduced activation in PIVC, hippocampus, anterior insula, inferior frontal gyrus, and anterior cingulate cortex, as well as connectivity changes among these regions, may be linked to long-term vestibular symptoms in patients with CSD

  15. [Some characteristics of vertigo in vestibular neuronitis].

    PubMed

    Skliut, I A; Likhachev, S A; Rybina, O V

    2004-01-01

    The authors present a detailed clinical analysis of objective neurological symptoms and vertigo in patients with vestibular neuronitis. Diagnostic criteria are specified allowing differentiation between vertigo and dizziness, pathognomonic signs of vestibular neuronitis are outlined. Peripheral location of the pathological process in vestibular neuronitis is suggested. How rotating vertigo is forming in patients with vestibular neuronitis is hypothesized.

  16. Visuo-Vestibular Interactions

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Session TA3 includes short reports covering: (1) Vestibulo-Oculomotor Interaction in Long-Term Microgravity; (2) Effects of Weightlessness on the Spatial Orientation of Visually Induced Eye Movements; (3) Adaptive Modification of the Three-Dimensional Vestibulo-Ocular Reflex during Prolonged Microgravity; (4) The Dynamic Change of Brain Potential Related to Selective Attention to Visual Signals from Left and Right Visual Fields; (5) Locomotor Errors Caused by Vestibular Suppression; and (6) A Novel, Image-Based Technique for Three-Dimensional Eye Measurement.

  17. Vestibular Rehabilitation Outcomes in the Elderly with Chronic Vestibular Dysfunction

    PubMed Central

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

    2012-01-01

    Background 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. Objectives The purpose of this study was to assess the effect of vestibular rehabilitation on dizziness in elderly patients with chronic vestibular dysfunction. Materials and Methods 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. Results 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. Conclusions Our study demonstrated that VRT is an effective therapeutic method for elderly patients with chronic vestibular dysfunction. PMID:23396380

  18. An update on vestibular physical therapy.

    PubMed

    Alghadir, Ahmad H; Iqbal, Zaheen A; Whitney, Susan L

    2013-01-01

    Vestibular physical therapy is a specialized exercise based intervention for management of symptoms associated with vestibular dysfunction that manifests itself as dizziness and imbalance related to position or movement of the body. The aim of this review is to evaluate and summarize the efficacy of vestibular physical therapy for the treatment of vestibular disorders. A literature review was conducted to identify references related to vestibular disorders plus rehabilitation. Articles ranged from descriptions of vestibular dysfunction, its diagnosis, treatment, and rehabilitation in various populations. Case studies, case series with no controls, and controlled studies support the use of vestibular rehabilitation physical therapy for persons with peripheral vestibular disorders. There are emerging data that support vestibular rehabilitation physical therapy for persons with central vestibular disorders.

  19. Disrupted functional connectivity of the default mode network due to acute vestibular deficit.

    PubMed

    Klingner, Carsten M; Volk, Gerd F; Brodoehl, Stefan; Witte, Otto W; Guntinas-Lichius, Orlando

    2014-01-01

    Vestibular neuritis is defined as a sudden unilateral partial failure of the vestibular nerve that impairs the forwarding of vestibular information from the labyrinth. The patient suffers from vertigo, horizontal nystagmus and postural instability with a tendency toward ipsilesional falls. Although vestibular neuritis is a common disease, the central mechanisms to compensate for the loss of precise vestibular information remain poorly understood. It was hypothesized that symptoms following acute vestibular neuritis originate from difficulties in the processing of diverging sensory information between the responsible brain networks. Accordingly an altered resting activity was shown in multiple brain areas of the task-positive network. Because of the known balance between the task-positive and task-negative networks (default mode network; DMN) we hypothesize that also the DMN is involved. Here, we employ functional magnetic resonance imaging (fMRI) in the resting state to investigate changes in the functional connectivity between the DMN and task-positive networks, in a longitudinal design combined with measurements of caloric function. We demonstrate an initially disturbed connectedness of the DMN after vestibular neuritis. We hypothesize that the disturbed connectivity between the default mode network and particular parts of the task-positive network might be related to a sustained utilization of processing capacity by diverging sensory information. The current results provide some insights into mechanisms of central compensation following an acute vestibular deficit and the importance of the DMN in this disease.

  20. Disrupted functional connectivity of the default mode network due to acute vestibular deficit

    PubMed Central

    Klingner, Carsten M.; Volk, Gerd F.; Brodoehl, Stefan; Witte, Otto W.; Guntinas-Lichius, Orlando

    2014-01-01

    Vestibular neuritis is defined as a sudden unilateral partial failure of the vestibular nerve that impairs the forwarding of vestibular information from the labyrinth. The patient suffers from vertigo, horizontal nystagmus and postural instability with a tendency toward ipsilesional falls. Although vestibular neuritis is a common disease, the central mechanisms to compensate for the loss of precise vestibular information remain poorly understood. It was hypothesized that symptoms following acute vestibular neuritis originate from difficulties in the processing of diverging sensory information between the responsible brain networks. Accordingly an altered resting activity was shown in multiple brain areas of the task-positive network. Because of the known balance between the task-positive and task-negative networks (default mode network; DMN) we hypothesize that also the DMN is involved. Here, we employ functional magnetic resonance imaging (fMRI) in the resting state to investigate changes in the functional connectivity between the DMN and task-positive networks, in a longitudinal design combined with measurements of caloric function. We demonstrate an initially disturbed connectedness of the DMN after vestibular neuritis. We hypothesize that the disturbed connectivity between the default mode network and particular parts of the task-positive network might be related to a sustained utilization of processing capacity by diverging sensory information. The current results provide some insights into mechanisms of central compensation following an acute vestibular deficit and the importance of the DMN in this disease. PMID:25379422

  1. Vestibular reflexes of otolith origin

    NASA Technical Reports Server (NTRS)

    Wilson, Victor J.

    1988-01-01

    The vestibular system and its role in the maintenance of posture and in motion sickness is investigated using cats as experimental subjects. The assumption is that better understanding of the physiology of vestibular pathways is not only of intrinsic value, but will help to explain and eventually alleviate the disturbances caused by vestibular malfunction, or by exposure to an unusual environment such as space. The first project deals with the influence on the spinal cord of stimulation of the vestibular labyrinth, particularly the otoliths. A second was concerned with the properties and neural basis of the tonic neck reflex. These two projects are related, because vestibulospinal and tonic neck reflexes interact in the maintenance of normal posture. The third project began with an interest in mechanisms of motion sickness, and eventually shifted to a study of central control of respiratory muscles involved in vomiting.

  2. 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

  3. Perspectives on Aging Vestibular Function

    PubMed Central

    Anson, Eric; Jeka, John

    2016-01-01

    Much is known about age-related anatomical changes in the vestibular system. Knowledge regarding how vestibular anatomical changes impact behavior for older adults continues to grow, in line with advancements in diagnostic testing. However, despite advancements in clinical diagnostics, much remains unknown about the functional impact that an aging vestibular system has on daily life activities such as standing and walking. Modern diagnostic tests are very good at characterizing neural activity of the isolated vestibular system, but the tests themselves are artificial and do not reflect the multisensory aspects of natural human behavior. Also, the majority of clinical diagnostic tests are passively applied because active behavior can enhance performance. In this perspective paper, we review anatomical and behavioral changes associated with an aging vestibular system and highlight several areas where a more functionally relevant perspective can be taken. For postural control, a multisensory perturbation approach could be used to bring balance rehabilitation into the arena of precision medicine. For walking and complex gaze stability, this may result in less physiologically specific impairments, but the trade-off would be a greater understanding of how the aging vestibular system truly impacts the daily life of older adults. PMID:26779116

  4. Vestibular abnormalities in congenital disorders.

    PubMed

    Sando, I; Orita, Y; Miura, M; Balaban, C D

    2001-10-01

    This paper reviews the histopathologic features of vestibular abnormalities in congenital disorders affecting the inner ear, based upon a comprehensive literature survey and a review of cases in our temporal bone collection. The review proceeds in three systematic steps. First, we surveyed associated diseases with the major phenotypic features of congenital abnormalities of the inner ear (including the internal auditory canal and otic capsule). Second, the vestibular anomalies are examined specifically. Finally, the anomalies are discussed from a developmental perspective. Among vestibular anomalies, a hypoplastic endolymphatic duct and sac are observed most frequently. Anomalies of the semicircular canals are also often observed. From embryological and clinical viewpoints, many of these resemble the structural features from fetal stages and appear to be associated with vestibular dysfunction. It is expected that progress in genetic analysis and accumulation of temporal bone specimens with vestibular abnormalities in congenital diseases will provide crucial information not only for pathology of those diseases, but also for genetic factors that are responsible for the specific vestibular abnormalities.

  5. Neuropharmacology of Vestibular System Disorders

    PubMed Central

    Soto, Enrique; Vega, Rosario

    2010-01-01

    This work reviews the neuropharmacology of the vestibular system, with an emphasis on the mechanism of action of drugs used in the treatment of vestibular disorders. Otolaryngologists are confronted with a rapidly changing field in which advances in the knowledge of ionic channel function and synaptic transmission mechanisms have led to the development of new scientific models for the understanding of vestibular dysfunction and its management. In particular, there have been recent advances in our knowledge of the fundamental mechanisms of vestibular system function and drug mechanisms of action. In this work, drugs acting on vestibular system have been grouped into two main categories according to their primary mechanisms of action: those with effects on neurotransmitters and neuromodulator receptors and those that act on voltage-gated ion channels. Particular attention is given in this review to drugs that may provide additional insight into the pathophysiology of vestibular diseases. A critical review of the pharmacology and highlights of the major advances are discussed in each case. PMID:20808544

  6. 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.

  7. Spatio-temporal pattern of vestibular information processing after brief caloric stimulation.

    PubMed

    Marcelli, Vincenzo; Esposito, Fabrizio; Aragri, Adriana; Furia, Teresa; Riccardi, Pasquale; Tosetti, Michela; Biagi, Laura; Marciano, Elio; Di Salle, Francesco

    2009-05-01

    Processing of vestibular information at the cortical and subcortical level is essential for head and body orientation in space and self-motion perception, but little is known about the neural dynamics of the brain regions of the vestibular system involved in this task. Neuroimaging studies using both galvanic and caloric stimulation have shown that several distinct cortical and subcortical structures can be activated during vestibular information processing. The insular cortex has been often targeted and presented as the central hub of the vestibular cortical system. Since very short pulses of cold water ear irrigation can generate a strong and prolonged vestibular response and a nystagmus, we explored the effects of this type of caloric stimulation for assessing the blood-oxygen-level-dependent (BOLD) dynamics of neural vestibular processing in a whole-brain event-related functional magnetic resonance imaging (fMRI) experiment. We evaluated the spatial layout and the temporal dynamics of the activated cortical and subcortical regions in time-locking with the instant of injection and were able to extract a robust pattern of neural activity involving the contra-lateral insular cortex, the thalamus, the brainstem and the cerebellum. No significant correlation with the temporal envelope of the nystagmus was found. The temporal analysis of the activation profiles highlighted a significantly longer duration of the evoked BOLD activity in the brainstem compared to the insular cortex suggesting a functional de-coupling between cortical and subcortical activity during the vestibular response.

  8. Parameter-adjusted stochastic resonance system for the aperiodic echo chirp signal in optimal FrFT domain

    NASA Astrophysics Data System (ADS)

    Lin, Li-feng; Yu, Lei; Wang, Huiqi; Zhong, Suchuan

    2017-02-01

    In order to improve the system performance for moving target detection and localization, this paper presents a new aperiodic chirp signal and additive noise driving stochastic dynamical system, in which the internal frequency has the linear variation matching with the driving frequency. By using the fractional Fourier transform (FrFT) operator with the optimal order, the proposed time-domain dynamical system is transformed into the equivalent FrFT-domain system driven by the periodic signal and noise. Therefore, system performance is conveniently analyzed from the view of output signal-to-noise ratio (SNR) in optimal FrFT domain. Simulation results demonstrate that the output SNR, as a function of system parameter, shows the different generalized SR behaviors in the case of various internal parameters of driving chirp signal and external parameters of the moving target.

  9. [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).

  10. Principles of vestibular physical therapy rehabilitation.

    PubMed

    Whitney, Susan L; Sparto, Patrick J

    2011-01-01

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

  11. Procedures for restoring vestibular disorders

    PubMed Central

    Walther, Leif Erik

    2005-01-01

    This paper will discuss therapeutic possibilities for disorders of the vestibular organs and the neurons involved, which confront ENT clinicians in everyday practice. Treatment of such disorders can be tackled either symptomatically or causally. The possible strategies for restoring the body's vestibular sense, visual function and co-ordination include medication, as well as physical and surgical procedures. Prophylactic or preventive measures are possible in some disorders which involve vertigo (bilateral vestibulopathy, kinetosis, height vertigo, vestibular disorders when diving (Tables 1 (Tab. 1) and 2 (Tab. 2)). Glucocorticoid and training therapy encourage the compensation of unilateral vestibular loss. In the case of a bilateral vestibular loss, it is important to treat the underlying disease (e.g. Cogan's disease). Although balance training does improve the patient's sense of balance, it will not restore it completely. In the case of Meniere's disease, there are a number of medications available to either treat bouts or to act as a prophylactic (e.g. dimenhydrinate or betahistine). In addition, there are non-ablative (sacculotomy) as well as ablative surgical procedures (e.g. labyrinthectomy, neurectomy of the vestibular nerve). In everyday practice, it has become common to proceed with low risk therapies initially. The physical treatment of mild postural vertigo can be carried out quickly and easily in outpatients (repositioning or liberatory maneuvers). In very rare cases it may be necessary to carry out a semicircular canal occlusion. Isolated disturbances of the otolith function or an involvement of the otolith can be found in roughly 50% of labyrinth disturbances. A specific surgical procedure to selectively block the otolith organs is currently being studied. When an external perilymph fistula involving loss of perilymph is suspected, an exploratory tympanotomy involving also the round and oval window niches must be carried out. A traumatic rupture of

  12. Negative emotional stimuli enhance vestibular processing.

    PubMed

    Preuss, Nora; Ellis, Andrew W; Mast, Fred W

    2015-08-01

    Recent studies have shown that vestibular stimulation can influence affective processes. In the present study, we examined whether emotional information can also modulate vestibular perception. Participants performed a vestibular discrimination task on a motion platform while viewing emotional pictures. Six different picture categories were taken from the International Affective Picture System: mutilation, threat, snakes, neutral objects, sports, and erotic pictures. Using a Bayesian hierarchical approach, we were able to show that vestibular discrimination improved when participants viewed emotionally negative pictures (mutilation, threat, snake) when compared to neutral/positive objects. We conclude that some of the mechanisms involved in the processing of vestibular information are also sensitive to emotional content. Emotional information signals importance and mobilizes the body for action. In case of danger, a successful motor response requires precise vestibular processing. Therefore, negative emotional information improves processing of vestibular information.

  13. Vestibular assessment in patients with vestibular schwannomas: what really matters?

    PubMed

    Teggi, R; Franzin, A; Spatola, G; Boari, N; Picozzi, P; Bailo, M; Piccioni, L O; Gagliardi, F; Mortini, P; Bussi, M

    2014-04-01

    Vestibular function is often underdiagnosed in vestibular schwannomas (VS). To evaluate it in a selected group of patients harbouring vestibular schwannomas, 64 patients were included in this study, recruited between March 2008 and June 2011 at our institution. All patients underwent Gd-enhanced MRI and complete neurotological evaluation before gamma knife surgery. Morphological measurements included Koos Classification and quantification of internal acoustic canal filling in length and diameter. Cochlear and vestibular functions were assessed considering pure tone and speech audiometry, bedside examination and caloric test by videonystagmography. A statistical analysis was performed to find possible correlations between morphological and cochleovestibular data. Patients with a higher intracanalicular length (ICL, mean value 8.59 and median 8.8 mm) of the tumour presented a higher value of UW than the subgroup with a lower length (51.9 ± 24.3% and 38.8 ± 18.1% respectively, p = 0.04), while no difference was detected for pure tone audiometry (PTA) values (50.9 ± 22.3 db and 51.1 ± 28.9 db respectively). Patients with a higher ICL also presented a higher rate of positive HIT (88% and 60% respectively, p = 0.006). Patients with a higher value of intracanalicular diameter (ICD, mean value 5.22 and median 5.15 mm) demonstrated higher values of UW (50.2 ± 29.1% and 39.3 ± 21% respectively, p = 0.03), but not different PTA (50.2 ± 29.1 db and 51.9 ± 29.9 db respectively). Finally, patients with a positive head impulse test (HIT) demonstrated significantly higher values of unilateral weakness (UW) (p = 0.001). Vestibular disorders are probably underdiagnosed in patients with VS. ICL and ICD seem to be the main parameters that correlate with vestibular function. Also, in case of small intracanalar T1 VS a slight increase of these variables can result in significant vestibular impairment. The data reported in the present study are not inconsistent with the

  14. Effect of Spike-Timing-Dependent Plasticity on Intrinsic Coherence Resonance in Newman-Watts Stochastic Hodgkin-Huxley Neuronal Networks

    NASA Astrophysics Data System (ADS)

    Xie, Huijuan; Gong, Yubing; Wang, Qi

    2016-07-01

    In this paper, we numerically study the effect of spike-timing-dependent plasticity (STDP) on coherence resonance (CR) induced by channel noise in adaptive Newman-Watts stochastic Hodgkin-Huxley neuron networks. It is found that STDP can either enhance or suppress the intrinsic CR when the adjusting rate of STDP decreases or increases. STDP can alter the effects of network randomness and network size on the intrinsic CR. Under STDP, for electrical coupling there are optimal network randomness and network size by which the intrinsic CR becomes strongest, however, for chemical coupling the intrinsic CR is always enhanced as network randomness or network size increases, which are different from the results for fixed coupling. These results show that the intrinsic CR of the neuronal networks can be either enhanced or suppressed by STDP, and there are optimal network randomness and network size by which the intrinsic CR becomes strongest. These findings could provide a new insight into the role of STDP for the information processing and transmission in neural systems.

  15. 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

  16. Vestibular Stimulation for Stress Management in Students

    PubMed Central

    Kumar, Sai Sailesh; Rajagopalan, Archana

    2016-01-01

    Introduction Although several methods are developed to alleviate stress among college students, logistic limitations in adopting them have limited their utility. Aim Hence, we aimed to test a very practical approach to alleviate stress among college students by achieving vestibular stimulation using swings. Materials and Methods In this study 60 male and female participants were randomly assigned into vestibular stimulation or control groups. Depression, anxiety, stress scores, sleep quality, heart rate, blood pressure, Autonomic functions, respiratory, haematological, cognitive function, Quality of life were recorded before and after 1st, 7th, 14th, 21st, 28th days of vestibular stimulation. Results STAI S and STAI T scores were significantly improved on day 28th following vestibular stimulation. Diastolic and mean arterial blood pressure were significantly decreased and remained within normal limits in vestibular group on day 28th following vestibular stimulation. Postural fall in blood pressure was significantly improved on day 14 onwards, following vestibular stimulation. Respiratory rate was significantly improved on day 7 onwards, following vestibular stimulation. PSQI sleep disturbance, PSQI sleep latency, PSQI total score and bleeding time was significantly improved following vestibular stimulation. Conclusion Our study supports the adoption of vestibular stimulation for stress management. Hence, placement of swings in college campuses must be considered, which may be a simple approach to alleviate stress among college students. PMID:27042457

  17. Current Treatment Options in Vestibular Migraine

    PubMed Central

    Obermann, Mark; Strupp, Michael

    2014-01-01

    Approximately 1% of the general population in western industrialized countries suffers from vestibular migraine. However, it remains widely unknown and often under diagnosed despite the recently published diagnostic criteria for vestibular migraine. Treatment trials that specialize on vestibular migraine are scarce and systematic randomized controlled clinical trials are now only emerging. This review summarizes the knowledge on the currently available treatment options that were tested specifically for vestibular migraine and gives an evidence-based, informed treatment recommendation with all its limitations. To date only two randomized controlled treatment trials provide limited evidence for the use of rizatriptan and zolmitriptan for the treatment of vestibular migraine attacks because of methodological shortcomings. There is an ongoing multicenter randomized placebo-controlled trial testing metoprolol 95 mg vs. placebo (PROVEMIG-trial). Therefore, the therapeutic recommendations for the prophylactic treatment of vestibular migraine are currently widely based on the guidelines of migraine with and without aura as well as expert opinion. PMID:25538676

  18. Dysconnectivity within the default mode in first-episode schizophrenia: a stochastic dynamic causal modeling study with functional magnetic resonance imaging.

    PubMed

    Bastos-Leite, António J; Ridgway, Gerard R; Silveira, Celeste; Norton, Andreia; Reis, Salomé; Friston, Karl J

    2015-01-01

    We report the first stochastic dynamic causal modeling (sDCM) study of effective connectivity within the default mode network (DMN) in schizophrenia. Thirty-three patients (9 women, mean age = 25.0 years, SD = 5) with a first episode of psychosis and diagnosis of schizophrenia--according to the Diagnostic and Statistic Manual of Mental Disorders, 4th edition, revised criteria--were studied. Fifteen healthy control subjects (4 women, mean age = 24.6 years, SD = 4) were included for comparison. All subjects underwent resting state functional magnetic resonance imaging (fMRI) interspersed with 2 periods of continuous picture viewing. The anterior frontal (AF), posterior cingulate (PC), and the left and right parietal nodes of the DMN were localized in an unbiased fashion using data from 16 independent healthy volunteers (using an identical fMRI protocol). We used sDCM to estimate directed connections between and within nodes of the DMN, which were subsequently compared with t tests at the between subject level. The excitatory effect of the PC node on the AF node and the inhibitory self-connection of the AF node were significantly weaker in patients (mean values = 0.013 and -0.048 Hz, SD = 0.09 and 0.05, respectively) relative to healthy subjects (mean values = 0.084 and -0.088 Hz, SD = 0.15 and 0.77, respectively; P < .05). In summary, sDCM revealed reduced effective connectivity to the AF node of the DMN--reflecting a reduced postsynaptic efficacy of prefrontal afferents--in patients with first-episode schizophrenia.

  19. Vestibular rehabilitation therapy for the dizzy patient.

    PubMed

    Tee, L H; Chee, N W C

    2005-05-01

    A customised vestibular rehabilitation therapy (VRT) programme is an important treatment modality in patients with vestibular dysfunction resulting in motion-provoked vertigo, oscillopsia (gaze instability), disequilibrium and gait disturbances. We discuss in this paper the patient selection criteria for VRT, rehabilitation strategies for unilateral and bilateral vestibular deficits, and some of the compelling evidence to support the use of VRT in treating such patients.

  20. 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

  1. Vestibular Function Research aboard Spacelab

    NASA Technical Reports Server (NTRS)

    Mah, R. W.; Daunton, N. G.

    1978-01-01

    NASA is planning to perform a series of Vestibular Function Research (VFR) investigations on the early STS missions to investigate those neurosensory and related physiological processes believed to be associated with the space flight nausea syndrome. The first flight is scheduled for the 1981 Spacelab III Mission in which four frog specimens, mounted on a frog tilting/centrifuge device, will be subjected to periodic acceleration stimuli and periods of artificial gravity. The vestibular nerve firing responses of each frog specimen will be monitored through implanted neutral bouyancy microelectrodes and transmitted to the ground for quick analysis during the flight. The experimentation will be directed at investigating: (1) adaptation to weightlessness; (2) response to acceleration stimuli; (3) response to artificial gravity (in a weightlessness environment) and (4) readaptation to earth's gravity upon return.

  2. Personality changes in patients with vestibular dysfunction

    PubMed Central

    Smith, Paul F.; Darlington, Cynthia L.

    2013-01-01

    The vestibular system is a sensory system that has evolved to detect linear and angular acceleration of the head in all planes so that the brain is not predominantly reliant on visual information to determine self-motion. Since the vestibular system first evolved in invertebrate species in order to detect gravitational vertical, it is likely that the central nervous system has developed a special dependence upon vestibular input. In addition to the deficits in eye movement and postural reflexes that occur following vestibular dysfunction, there is convincing evidence that vestibular loss also causes cognitive and emotional disorders, some of which may be due to the reflexive deficits and some of which are related to the role that ascending vestibular pathways to the limbic system and neocortex play in the sense of spatial orientation. Beyond this, however, patients with vestibular disorders have been reported to experience other personality changes that suggest that vestibular sensation is implicated in the sense of self. These are depersonalization and derealization symptoms such as feeling “spaced out”, “body feeling strange” and “not feeling in control of self”. We propose in this review that these symptoms suggest that the vestibular system may make a unique contribution to the concept of self through information regarding self-motion and self-location that it transmits, albeit indirectly, to areas of the brain such as the temporo-parietal junction (TPJ). PMID:24194706

  3. 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.

  4. Movement Symmetries and the Mammalian Vestibular System

    NASA Astrophysics Data System (ADS)

    McCollum, Gin; Boyle, Richard

    2000-03-01

    Unity of movement requires vertebrates to have an ability to symmetrize along the midline. For example, human erect stance involves symmetry with respect to gravity. The mammalian vestibular system provides a mechanism for maintaining symmetries, which is also open to influence and adaptation by the rest of the organism. The vestibular system includes the inner ear endorgans and central nuclei, along with projections to oculomotor, cerebellar, thalamic, and spinal motor centers. The vestibular endorgans - the semicircular canals and the otoliths - use sensory hairs to register inertia. The vestibular endorgans are right-left symmetric and the semicircular canals form an approximately orthogonal coordinate system for angular motion. Primary afferent axons project from the endorgans to the vestibular nuclei (and a few other places). The vestibular nuclei integrate vestibular, visual, and somatosensory signals, along with a proposed copy of the voluntary motor command and signals from other central structures. The relationship between the canals and the otoliths gives rise to symmetries among neurons, in the organization among the several vestibular nuclei, and in the projections from the vestibular nuclei. These symmetries organize the space of body movements so that functional relationships are maintained in spite of the many free variables of body movement. They also provide a foundation for adaptive reinterpretation of the relationship between canal and otolith signals, for example in freefall.

  5. Vestibular insights into cognition and psychiatry.

    PubMed

    Gurvich, Caroline; Maller, Jerome J; Lithgow, Brian; Haghgooie, Saman; Kulkarni, Jayashri

    2013-11-06

    The vestibular system has traditionally been thought of as a balance apparatus; however, accumulating research suggests an association between vestibular function and psychiatric and cognitive symptoms, even when balance is measurably unaffected. There are several brain regions that are implicated in both vestibular pathways and psychiatric disorders. The present review examines the anatomical associations between the vestibular system and various psychiatric disorders. Despite the lack of direct evidence for vestibular pathology in the key psychiatric disorders selected for this review, there is a substantial body of literature implicating the vestibular system in each of the selected psychiatric disorders. The second part of this review provides complimentary evidence showing the link between vestibular dysfunction and vestibular stimulation upon cognitive and psychiatric symptoms. In summary, emerging research suggests the vestibular system can be considered a potential window for exploring brain function beyond that of maintenance of balance, and into areas of cognitive, affective and psychiatric symptomology. Given the paucity of biological and diagnostic markers in psychiatry, novel avenues to explore brain function in psychiatric disorders are of particular interest and warrant further exploration.

  6. Changing perspective: The role of vestibular signals.

    PubMed

    Deroualle, Diane; Borel, Liliane; Devèze, Arnaud; Lopez, Christophe

    2015-12-01

    Social interactions depend on mechanisms such as the ability to take another person's viewpoint, i.e. visuo-spatial perspective taking. However, little is known about the sensorimotor mechanisms underpinning perspective taking. Because vestibular signals play roles in mental rotation and spatial cognition tasks and because damage to the vestibular cortex can disturb egocentric perspective, vestibular signals stand as important candidates for the sensorimotor foundations of perspective taking. Yet, no study merged natural full-body vestibular stimulations and explicit visuo-spatial perspective taking tasks in virtual environments. In Experiment 1, we combined natural vestibular stimulation on a rotatory chair with virtual reality to test how vestibular signals are processed to simulate the viewpoint of a distant avatar. While they were rotated, participants tossed a ball to a virtual character from the viewpoint of a distant avatar. Our results showed that vestibular signals influence perspective taking in a direction-specific way: participants were faster when their physical body rotated in the same direction as the mental rotation needed to take the avatar's viewpoint. In Experiment 2, participants realized 3D object mental rotations, which did not involve perspective taking, during the same whole-body vestibular stimulation. Our results demonstrated that vestibular stimulation did not affect 3D object mental rotations. Altogether, these data indicate that vestibular signals have a direction-specific influence on visuo-spatial perspective taking (self-centered mental imagery), but not a general effect on mental imagery. Findings from this study suggest that vestibular signals contribute to one of the most crucial mechanisms of social cognition: understanding others' actions.

  7. Compensation of Vestibular Function and Plasticity of Vestibular Nucleus after Unilateral Cochleostomy

    PubMed Central

    Suh, Myung-Whan; Hyun, Jaihwan; Lyu, Ah-Ra; Kim, Dong Woon; Park, Sung Jae; Choi, Jin Woong; Hur, Gang Min

    2016-01-01

    Dizziness and vertigo frequently occur after cochlear implantation (CI) surgery, particularly during the early stages. It could recover over time but some of the patients suffered from delayed or sustained vestibular symptoms after CI. This study used rat animal models to investigate the effect of unilateral cochleostomy on the vestibular organs over time. Twenty-seven Sprague Dawley rats underwent cochleostomy to evaluate the postoperative changes in hearing threshold, gain and symmetry of the vestibular ocular response, overall balance function, number of hair cells in the crista, and the c-Fos activity in the brainstem vestibular nucleus. Loss of vestibular function was observed during the early stages, but function recovered partially over time. Histopathological findings demonstrated a mild decrease in vestibular hair cells numbers. Increased c-Fos immunoreactivity in the vestibular nucleus, observed in the early stages after cochleostomy, decreased over time. Cochleostomy is a risk factor for peripheral vestibular organ damage that can cause functional impairment in the peripheral vestibular organs. Altered vestibular nucleus activity may be associated with vestibular compensation and plasticity after unilateral cochleostomy. PMID:26881130

  8. Incomplete segregation of endorgan-specific vestibular ganglion cells in mice and rats

    NASA Technical Reports Server (NTRS)

    Maklad, A.; Fritzsch, B.

    1999-01-01

    The endorgan-specific distribution of vestibular ganglion cells was studied in neonatal and postnatal rats and mice using indocarbocyanine dye (DiI) and dextran amines for retrograde and anterograde labeling. Retrograde DiI tracing from the anterior vertical canal labeled neurons scattered throughout the whole superior vestibular ganglion, with denser labeling at the dorsal and central regions. Horizontal canal neurons were scattered along the dorsoventral axis with more clustering toward the dorsal and ventral poles of this axis. Utricular ganglion cells occupied predominantly the central region of the superior vestibular ganglion. This utricular population overlapped with both the anterior vertical and horizontal canals' ganglion cells. Posterior vertical canal neurons were clustered in the posterior part of the inferior vestibular ganglion. The saccular neurons were distributed in the two parts of the vestibular ganglion, the superior and inferior ganglia. Within the inferior ganglion, the saccular neurons were clustered in the anterior part. In the superior ganglion, the saccular neurons were widely scattered throughout the whole ganglion with more numerous neurons at the posterior half. Small and large neurons were labeled from all endorgans. Examination of the fiber trajectory within the superior division of the vestibular nerve showed no clear lamination of the fibers innervating the different endorgans. These results demonstrate an overlapping pattern between the different populations within the superior ganglion, while in the inferior ganglion, the posterior canal and saccular neurons show tighter clustering but incomplete segregation. This distribution implies that the ganglion cells are assigned for their target during development in a stochastic rather than topographical fashion.

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

    PubMed

    Adamec, Ivan; Skorić, Magdalena Krbot; Handžić, Jadranka; Barušić, Anabella Karla; Bach, Ivo; Gabelić, Tereza; Habek, Mario

    2014-04-01

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

  10. Vestibular Function and Activities of Daily Living

    PubMed Central

    Harun, Aisha; Semenov, Yevgeniy R.; Agrawal, Yuri

    2015-01-01

    Objective: Vestibular dysfunction increases with age and is associated with mobility difficulties and fall risk in older individuals. We evaluated whether vestibular function influences the ability to perform activities of daily living (ADLs). Method: We analyzed the 1999 to 2004 National Health and Nutrition Examination Survey of adults aged older than 40 years (N = 5,017). Vestibular function was assessed with the Modified Romberg test. We evaluated the association between vestibular function and difficulty level in performing specific basic and instrumental ADLs, and total number of ADL impairments. Results: Vestibular dysfunction was associated with significantly higher odds of difficulty with nine ADLs, most strongly with difficulty managing finances (odds ratio [OR] = 2.64, 95% confidence interval [CI] = [1.18, 5.90]). In addition, vestibular dysfunction was associated with a significantly greater number of ADL impairments (β = .21, 95% CI = [0.09, 0.33]). This effect size was comparable with the influence of heavy smoking (β = .21, 95% CI = [0.06, 0.36]) and hypertension (β = .10, 95% CI = [0.02, 0.18]) on the number of ADL impairments. Conclusion: Vestibular dysfunction significantly influences ADL difficulty, most strongly with a cognitive rather than mobility-based task. These findings underscore the importance of vestibular inputs for both cognitive and physical daily activities. PMID:26753170

  11. Vestibular rehabilitation of older adults with dizziness.

    PubMed

    Alrwaily, Muhammad; Whitney, Susan L

    2011-04-01

    The role of rehabilitation for treatment of older adults with dizziness and balance disorders is reviewed. Theories related to functional recovery from peripheral and central vestibular disorders are presented. Suggestions on which older adults might benefit from vestibular rehabilitation therapy are presented. Promising innovative rehabilitation strategies and technologies that might enhance recovery of the older adult with balance dysfunction are discussed.

  12. 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.

  13. Vestibular tests in the selection of cosmonauts

    NASA Astrophysics Data System (ADS)

    Kubiczkowa, Janusza

    Vestibulo-vegetative disorders in cosmonauts and astronauts occurring during space flight compel otolaryngologists to search for vestibular tests enabling a precise evaluation of the activity of the vestibular apparatus and showing disposition to motion sickness. Otoneurological investigation of Polish candidates for cosmonaut status consisted of the following vestibular tests: caloric, rotatory, optokinetic, swinging torsion, statokinesimetric and vestibulo-vegetative. The value of various vestibular tests for aviation and space medicine is presented in this paper, taking into account the results of investigations of the equilibrium system with the group of pilots selected for space flight as well as extensive experience with candidates for the air service and also trained pilots and patients. The relatively frequent lack of correlation between the results of the applied tests, which renders difficult the proper evaluation of the equilibrium system, is emphasized in the paper. Finally, the results of investigations of acute habituation of the vestibular apparatus are discussed.

  14. Vestibular Function and Depersonalization/Derealization Symptoms.

    PubMed

    Jáuregui Renaud, Kathrine

    2015-01-01

    Patients with an acquired sensory dysfunction may experience symptoms of detachment from self or from the environment, which are related primarily to nonspecific symptoms of common mental disorders and secondarily, to the specific sensory dysfunction. This is consistent with the proposal that sensory dysfunction could provoke distress and a discrepancy between the multi-sensory frame given by experience and the actual perception. Both vestibular stimuli and vestibular dysfunction can underlie unreal experiences. Vestibular afferents provide a frame of reference (linear and angular head acceleration) within which spatial information from other senses is interpreted. This paper reviews evidence that symptoms of depersonalization/derealization associated with vestibular dysfunction are a consequence of a sensory mismatch between disordered vestibular input and other sensory signals of orientation.

  15. 7-Tesla MRI demonstrates absence of structural lesions in patients with vestibular paroxysmia

    PubMed Central

    Rommer, Paulus S.; Wiest, Gerald; Kronnerwetter, Claudia; Zach, Heidemarie; Loader, Benjamin; Elwischger, Kirsten; Trattnig, Siegfried

    2015-01-01

    Vestibular parxoysmia (VP) is a rare vestibular disorder. A neurovascular cross-compression (NVCC) between the vestibulochochlear nerve and an artery seems to be responsible for short attacks of vertigo in this entity. An NVCC can be seen in up to every fourth subject. The significance of these findings is not clear, as not all subjects suffer from symptoms. The aim of the present study was to assess possible structural lesions of the vestibulocochlear nerve by means of high field magnetic resonance imaging (MRI), and whether high field MRI may help to differentiate symptomatic from asymptomatic subjects. 7 Tesla MRI was performed in six patients with VP and confirmed NVCC seen on 1.5 and 3.0 MRI. No structural abnormalities were detected in any of the patients in 7 Tesla MRI. These findings imply that high field MRI does not help to differentiate between symptomatic and asymptomatic NVCC and that the symptoms of VP are not caused by structural nerve lesions. This supports the hypothesis that the nystagmus associated with VP has to be conceived pathophysiologically as an excitatory vestibular phenomenon, being not related to vestibular hypofunction. 7 Tesla MRI outperforms conventional MRI in image resolution and may be useful in vestibular disorders. PMID:26106306

  16. 7-Tesla MRI demonstrates absence of structural lesions in patients with vestibular paroxysmia.

    PubMed

    Rommer, Paulus S; Wiest, Gerald; Kronnerwetter, Claudia; Zach, Heidemarie; Loader, Benjamin; Elwischger, Kirsten; Trattnig, Siegfried

    2015-01-01

    Vestibular parxoysmia (VP) is a rare vestibular disorder. A neurovascular cross-compression (NVCC) between the vestibulochochlear nerve and an artery seems to be responsible for short attacks of vertigo in this entity. An NVCC can be seen in up to every fourth subject. The significance of these findings is not clear, as not all subjects suffer from symptoms. The aim of the present study was to assess possible structural lesions of the vestibulocochlear nerve by means of high field magnetic resonance imaging (MRI), and whether high field MRI may help to differentiate symptomatic from asymptomatic subjects. 7 Tesla MRI was performed in six patients with VP and confirmed NVCC seen on 1.5 and 3.0 MRI. No structural abnormalities were detected in any of the patients in 7 Tesla MRI. These findings imply that high field MRI does not help to differentiate between symptomatic and asymptomatic NVCC and that the symptoms of VP are not caused by structural nerve lesions. This supports the hypothesis that the nystagmus associated with VP has to be conceived pathophysiologically as an excitatory vestibular phenomenon, being not related to vestibular hypofunction. 7 Tesla MRI outperforms conventional MRI in image resolution and may be useful in vestibular disorders.

  17. Prevalence of vestibular dysfunction in patients with vestibular schwannoma using video head-impulses and vestibular-evoked potentials.

    PubMed

    Taylor, Rachael L; Kong, Jonathan; Flanagan, Sean; Pogson, Jacob; Croxson, Glen; Pohl, David; Welgampola, Miriam S

    2015-05-01

    We sought to investigate the utility of new non-invasive tests of semicircular-canal and otolith function that are usable in the neuro-otology office practice in patients with vestibular schwannoma. Fifty patients with vestibular schwannoma were assessed using a 5-item battery consisting of air-conducted cervical- and bone conducted ocular-vestibular-evoked myogenic potentials (AC cVEMPs and BC oVEMPs) and video head impulse testing (vHIT) in all three canal planes. VEMP asymmetry ratios, latencies, and vHIT gains were used to determine the test sensitivity, relationship with tumour size and the pattern of vestibular nerve involvement. The percentage of abnormalities for each of the five tests for the entire sample ranged between 36.2-61.7%. In 58.3 % of patients, test abnormalities were referable to both superior and inferior vestibular nerve divisions. Selective inferior nerve dysfunction was identified in 10.4% and superior nerve dysfunction in 12.5%. The remaining 18.8% of patients demonstrated a normal test profile. The sensitivity of the 5-item battery increased with tumour size and all patients with medium to large (>14 mm) schwannoma had at least two abnormal vestibular test result. Our results indicate that dysfunction of the superior and inferior vestibular nerve evolves in parallel for most patients with schwannoma. Unexplained vHIT and VEMP asymmetry should alert otologists and neurologists to undertake imaging in patients presenting with non-specific disequilibrium or vertigo.

  18. Stochastic games

    PubMed Central

    Solan, Eilon; Vieille, Nicolas

    2015-01-01

    In 1953, Lloyd Shapley contributed his paper “Stochastic games” to PNAS. In this paper, he defined the model of stochastic games, which were the first general dynamic model of a game to be defined, and proved that it admits a stationary equilibrium. In this Perspective, we summarize the historical context and the impact of Shapley’s contribution. PMID:26556883

  19. Genetic disorders of the vestibular system

    PubMed Central

    Eppsteiner, Robert W.; Smith, Richard J.H.

    2012-01-01

    Purpose of review This review highlights the current body of literature related to the genetics of inherited vestibular disorders and provides a framework for the characterization of these disorders. We emphasize peripheral causes of vestibular dysfunction and highlight recent advances in the field, point out gaps in understanding, and focus on key areas for future investigation. Recent findings The discovery of a modifier gene that leads to a more severe Usher syndrome phenotype calls into question the assumption that Usher syndrome is universally a monogenic disorder. Despite the use of several investigational approaches, the genetic basis of Menière’s disease remains poorly understood. Evidence for a vestibular phenotype associated with DFNB1 suggests that mutations in other genes causally related to nonsyndromic hearing loss also may have an unrecognized vestibular phenotype. Summary Our understanding of the genetic basis for vestibular disorders is superficial. Significant challenges include defining the genetics of inherited isolated vestibular dysfunction and understanding the pathological basis of Menière’s disease. However, improved characterization of inherited vestibular dysfunction, coupled with advanced genetic techniques such as targeted genome capture and massively parallel sequencing, provides an opportunity to investigate these diseases at the genetic level. PMID:21825995

  20. The anatomy of the vestibular nuclei.

    PubMed

    Highstein, Stephen M; Holstein, Gay R

    2006-01-01

    The vestibular portion of the eighth cranial nerve informs the brain about the linear and angular movements of the head in space and the position of the head with respect to gravity. The termination sites of these eighth nerve afferents define the territory of the vestibular nuclei in the brainstem. (There is also a subset of afferents that project directly to the cerebellum.) This chapter reviews the anatomical organization of the vestibular nuclei, and the anatomy of the pathways from the nuclei to various target areas in the brain. The cytoarchitectonics of the vestibular brainstem are discussed, since these features have been used to distinguish the individual nuclei. The neurochemical phenotype of vestibular neurons and pathways are also summarized because the chemical anatomy of the system contributes to its signal-processing capabilities. Similarly, the morphologic features of short-axon local circuit neurons and long-axon cells with extrinsic projections are described in detail, since these structural attributes of the neurons are critical to their functional potential. Finally, the composition and hodology of the afferent and efferent pathways of the vestibular nuclei are discussed. In sum, this chapter reviews the morphology, chemoanatomy, connectivity, and synaptology of the vestibular nuclei.

  1. Aging of the Human Vestibular System

    PubMed Central

    Zalewski, Christopher K.

    2015-01-01

    Aging affects every sensory system in the body, including the vestibular system. Although its impact is often difficult to quantify, the deleterious impact of aging on the vestibular system is serious both medically and economically. The deterioration of the vestibular sensory end organs has been known since the 1970s; however, the measurable impact from these anatomical changes remains elusive. Tests of vestibular function either fall short in their ability to quantify such anatomical deterioration, or they are insensitive to the associated physiologic decline and/or central compensatory mechanisms that accompany the vestibular aging process. When compared with healthy younger individuals, a paucity of subtle differences in test results has been reported in the healthy older population, and those differences are often observed only in response to nontraditional and/or more robust stimuli. In addition, the reported differences are often clinically insignificant insomuch that the recorded physiologic responses from the elderly often fall within the wide normative response ranges identified for normal healthy adults. The damaging economic impact of such vestibular sensory decline manifests itself in an exponential increase in geriatric dizziness and a subsequent higher prevalence of injurious falls. An estimated $10 to $20 billion dollar annual cost has been reported to be associated with falls-related injuries and is the sixth leading cause of death in the elderly population, with a 20% mortality rate. With an estimated 115% increase in the geriatric population over 65 years of age by the year 2050, the number of balanced-disordered patients with a declining vestibular system is certain to reach near epidemic proportions. An understanding of the effects of age on the vestibular system is imperative if clinicians are to better manage elderly patients with balance disorders, dizziness, and vestibular disease. PMID:27516717

  2. 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

  3. 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.

  4. Stochastic Modeling of Laminar-Turbulent Transition

    NASA Technical Reports Server (NTRS)

    Rubinstein, Robert; Choudhari, Meelan

    2002-01-01

    Stochastic versions of stability equations are developed in order to develop integrated models of transition and turbulence and to understand the effects of uncertain initial conditions on disturbance growth. Stochastic forms of the resonant triad equations, a high Reynolds number asymptotic theory, and the parabolized stability equations are developed.

  5. Vestibular development in marsupials and monotremes.

    PubMed

    Ashwell, Ken W S; Shulruf, Boaz

    2014-04-01

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

  6. 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

  7. Vestibular-visual interactions in flight simulators

    NASA Technical Reports Server (NTRS)

    Clark, B.

    1977-01-01

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

  8. Vestibular development in marsupials and monotremes

    PubMed Central

    Ashwell, Ken W S; Shulruf, Boaz

    2014-01-01

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

  9. Vestibular Impairment in Frontotemporal Dementia Syndrome

    PubMed Central

    Nakamagoe, Kiyotaka; Kadono, Kotarou; Koganezawa, Tadachika; Takiguchi, Mao; Terada, Makoto; Yamamoto, Fumiko; Moriyama, Tetsuya; Yanagiha, Kumi; Nohara, Seitaro; Tozaka, Naoki; Miyake, Zenshi; Aizawa, Satoshi; Furusho, Kentaro; Tamaoka, Akira

    2016-01-01

    Background No studies to date have attempted to evaluate frontotemporal lobar degeneration from the perspective of the vestibular system. Objective The present study examined vestibular function in patients with frontotemporal dementia (FTD) clinical syndrome and evaluated whether vestibular disorders are involved in the clinical symptoms due to FTD. Methods Fourteen patients with FTD syndrome, as well as healthy elderly controls without dementia, were included in the present study. All subjects underwent vestibular function tests using electronystagmography, such as caloric tests and visual suppression (VS) tests, in which the induced caloric nystagmus was suppressed by visual stimuli. The association between clinical symptoms and vestibular function in the FTD syndrome group was further examined. Results In the FTD syndrome group, caloric nystagmus was not necessarily suppressed during VS tests. Furthermore, VS was observed to be significantly impaired in FTD syndrome patients with gait disturbance as compared to those without such disturbance. Conclusion The present study revealed that impairment of VS in patients with FTD results in an inability to regulate vestibular function by means of visual perception, regardless of multiple presumed neuropathological backgrounds. This could also be associated with gait disturbance in patients with FTD syndrome. PMID:27350780

  10. Vestibular function assessment using the NIH Toolbox

    PubMed Central

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

    2013-01-01

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

  11. [Vestibular neuronitis: pathophysiology, diagnosis and treatment].

    PubMed

    Zaper, Dinka; Adamec, Ivan; Gabelić, Tereza; Krbot, Magdalena; Isgum, Velimir; Hajnsek, Sanja; Habek, Mario

    2012-01-01

    Vestibular neuritis (VN) is one of the most common causes of peripheral vertigo. Caloric testing has been the traditional gold standard for detecting a peripheral vestibular deficit, but some recently developed bedside tests (head thrust, head heave, head shake and vibration test) were evaluated as a good alternative with similar sensitivity and specificity. These tests have shown both diagnostic value in the short term and prognostic value in the long term, and have availability and ease of use as an advantage. As an addition to clinical examination, vestibular evoked myogenic potentials can differentiate between involvement of superior and inferior branch of the vestibular nerve, but also between peripheral and central lesions. Although glucocorticoids are currently widely used in the treatment of VN, there is a lack of evidence for the validity of their administration. There are a number of high quality clinical trials that suggest vestibular rehabilitation exercises, which are based on the mechanisms of vestibular compensation, in the managment of VN. This review will focus on the latest developments in the pathophysiology, diagnosis and treatment of patients with VN.

  12. Idiopathic Scoliosis and the Vestibular System

    PubMed Central

    Hawasli, Ammar H.; Hullar, Timothy E.; Dorward, Ian G.

    2014-01-01

    Purpose Despite its high prevalence, the etiology underlying idiopathic scoliosis remains unclear. Although initial scrutiny has focused on genetic, biochemical, biomechanical, nutritional and congenital causes, there is growing evidence that aberrations in the vestibular system may play a role in the etiology of scoliosis. In this article, we discuss putative mechanisms for adolescent idiopathic scoliosis and review the current evidence supporting a role for the vestibular system in adolescent idiopathic scoliosis. Methods A comprehensive search of the English literature was performed using PubMed (http://www.ncbi.nlm.nih.gov/pubmed). Research articles studying interactions between adolescent idiopathic scoliosis and the vestibular system were selected and evaluated for inclusion in a literature review. Results Eighteen manuscripts of level 3-4 clinical evidence to support an association between AIS and dysfunction of the vestibular system. These studies include data from physiologic and morphologic studies in humans. Clinical data are supported by animal model studies to suggest a causative link between the vestibular system and AIS. Conclusions Clinical data and a limited number of animal model studies suggest a causative role of the vestibular system in AIS, although this association has not been reproduced in all studies. PMID:25430569

  13. 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.

  14. Presentation of large vestibular aqueduct syndrome to a dizziness unit.

    PubMed

    Schessel, D A; Nedzelski, J M

    1992-08-01

    An abnormally enlarged vestibular aqueduct has been associated with sensorineural hearing loss in children. Vestibular complaints, in this patient population, have not been characterized. Several patients have presented to the dizziness unit at Sunnybrook with vestibular related complaints. These patients all had sensorineural hearing loss noted in childhood. All provided recollections of periods of imbalance and vertigo. High resolution CT scan documented the presence of bilateral enlarged vestibular aqueducts. The Large Vestibular Aqueduct Syndrome (LVAS) will be discussed with reference to the pathophysiology of the vestibular complaints.

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

    PubMed

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

    2012-10-30

    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.

  16. Depersonalisation/derealisation symptoms in vestibular disease

    PubMed Central

    Sang, F Yen Pik; Jáuregui‐Renaud, K; Green, D A; Bronstein, A M; Gresty, M A

    2006-01-01

    Background Depersonalisation is a subjective experience of unreality and detachment from the self often accompanied by derealisation; the experience of the external world appearing to be strange or unreal. Feelings of unreality can be evoked by disorienting vestibular stimulation. Objective To identify the prevalence of depersonalisation/derealisation symptoms in patients with peripheral vestibular disease and experimentally to induce these symptoms by vestibular stimulation. Methods 121 healthy subjects and 50 patients with peripheral vestibular disease participated in the study. For comparison with the patients a subgroup of 50 age matched healthy subjects was delineated. All completed (1) an in‐house health screening questionnaire; (2) the General Health Questionnaire (GHQ‐12); (3) the 28‐item depersonalisation/derealisation inventory of Cox and Swinson (2002). Experimental verification of “vestibular induced” depersonalisation/derealisation was assessed in 20 patients and 20 controls during caloric irrigation of the labyrinths. Results The frequency and severity of symptoms in vestibular patients was significantly higher than in controls. In controls the most common experiences were of “déjà vu” and “difficulty in concentrating/attending”. In contrast, apart from dizziness, patients most frequently reported derealisation symptoms of “feel as if walking on shifting ground”, “body feels strange/not being in control of self”, and “feel ‘spacey' or ‘spaced out'”. Items permitted discrimination between healthy subjects and vestibular patients in 92% of the cases. Apart from dizziness, caloric stimulation induced depersonalisation/derealisation symptoms which healthy subjects denied ever experiencing before, while patients reported that the symptoms were similar to those encountered during their disease. Conclusions Depersonalisation/derealisation symptoms are both different in quality and more frequent under conditions of non

  17. Multiple Unilateral Vestibular Schwannomas: Segmental NF2 or Sporadic Occurrence?

    PubMed Central

    Carlson, Matthew L.; Gompel, Jamie J. Van

    2016-01-01

    Objective To report a case of a patient presenting with two separate unilateral vestibular schwannomas (VSs) without other stigmata of neurofibromatosis type 2 (NF2). Study Design This article discusses a case report and review of the literature. Setting Tertiary academic referral center. Participants A 41-year-old female was referred for evaluation of a left-sided 1.8-cm cerebellopontine angle tumor centered on the porus acusticus and a separate ipsilateral 3-mm intracanalicular tumor appearing to arise from the superior vestibular nerve. The patient denied a family history of NF2. Neurotologic examination was unremarkable and close review of magnetic resonance imaging did not find any other stigmata of NF2. Results The patient underwent left-sided retrosigmoid craniotomy with gross total resection of both tumors. Final pathology confirmed benign schwannoma. The INI1/SMARCB1 staining pattern did not suggest NF2 or schwannomatosis. Conclusions This is only the third report of a case with multiple unilateral VSs occurring in a patient without other features of NF2. Herein, the authors review the two other reports and discuss potential mechanisms for this rare phenomenon. PMID:27354931

  18. Large Vestibular Schwannomas Presenting during Pregnancy: Management Strategies

    PubMed Central

    Shah, Kushal J.; Chamoun, Roukoz B.

    2014-01-01

    Objective Large vestibular schwannomas rarely present in pregnant women. Diagnosis and management of these tumors during pregnancy present a therapeutic challenge. Methods A 20-year-old primigravida woman at 26 weeks' gestation was transferred to our facility with gait imbalance, left facial weakness, left ear hearing loss, and recent nausea and vomiting. Magnetic resonance imaging revealed a large left cerebellopontine angle mass with extension into the left internal auditory canal and compression of the fourth ventricle resulting in mild hydrocephalus. The patient was admitted with a plan for early delivery at 32 weeks followed by tumor resection. One week later, the patient's headache and neurologic symptoms worsened due to increased hydrocephalus; a ventriculoperitoneal shunt was placed. The next day, an emergent cesarean delivery was performed due to worsening respiratory status. Four days later, a tracheostomy and percutaneous endoscopic gastrostomy tube were placed due to dysphagia. Eight days after the delivery, the mass was resected with a left retrosigmoid approach without complications. Immunohistochemistry confirmed vestibular cellular schwannoma on cranial nerve VIII showing unusually high mitotic activity. Results The patient was discharged to inpatient rehabilitation on postoperative day 12 without new neurologic deficit. At 1 month, the patient was swallowing without aspiration. Her facial sensation had returned, her facial weakness remained stable, and her gait was significantly improved. Conclusion If the patient is neurologically stable, the best option is to delay resection until after delivery. If resection is necessary during pregnancy, the optimal time is during the second trimester. PMID:25072015

  19. Stochastic model of the residual acceleration environment in microgravity

    NASA Technical Reports Server (NTRS)

    Vinals, Jorge

    1994-01-01

    We describe a theoretical investigation of the effects that stochastic residual accelerations (g-jitter) onboard spacecraft can have on experiments conducted in a microgravity environment. We first introduce a stochastic model of the residual acceleration field, and develop a numerical algorithm to solve the equations governing fluid flow that allow for a stochastic body force. We next summarize our studies of two generic situations: stochastic parametric resonance and the onset of convective flow induced by a fluctuating acceleration field.

  20. Neurotology symptoms at referral to vestibular evaluation

    PubMed Central

    2013-01-01

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

  1. Computational Approaches to Vestibular Research

    NASA Technical Reports Server (NTRS)

    Ross, Muriel D.; Wade, Charles E. (Technical Monitor)

    1994-01-01

    The Biocomputation Center at NASA Ames Research Center is dedicated to a union between computational, experimental and theoretical approaches to the study of neuroscience and of life sciences in general. The current emphasis is on computer reconstruction and visualization of vestibular macular architecture in three-dimensions (3-D), and on mathematical modeling and computer simulation of neural activity in the functioning system. Our methods are being used to interpret the influence of spaceflight on mammalian vestibular maculas in a model system, that of the adult Sprague-Dawley rat. More than twenty 3-D reconstructions of type I and type II hair cells and their afferents have been completed by digitization of contours traced from serial sections photographed in a transmission electron microscope. This labor-intensive method has now been replace d by a semiautomated method developed in the Biocomputation Center in which conventional photography is eliminated. All viewing, storage and manipulation of original data is done using Silicon Graphics workstations. Recent improvements to the software include a new mesh generation method for connecting contours. This method will permit the investigator to describe any surface, regardless of complexity, including highly branched structures such as are routinely found in neurons. This same mesh can be used for 3-D, finite volume simulation of synapse activation and voltage spread on neuronal surfaces visualized via the reconstruction process. These simulations help the investigator interpret the relationship between neuroarchitecture and physiology, and are of assistance in determining which experiments will best test theoretical interpretations. Data are also used to develop abstract, 3-D models that dynamically display neuronal activity ongoing in the system. Finally, the same data can be used to visualize the neural tissue in a virtual environment. Our exhibit will depict capabilities of our computational approaches and

  2. 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

  3. 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.

  4. Visual dependency and dizziness after vestibular neuritis.

    PubMed

    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.

  5. 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

  6. Sensorial countermeasures for vestibular spatial disorientation.

    PubMed

    Paillard, Aurore C; Quarck, Gaëlle; Denise, Pierre

    2014-05-01

    Spatial disorientation is defined as an erroneous body orientation perceived by pilots during flights. Limits of the vestibular system provoke frequent spatial disorientation mishaps. Although vestibular spatial disorientation is experienced frequently in aviation, there is no intuitive countermeasure against spatial disorientation mishaps to date. The aim of this review is to describe the current sensorial countermeasures and to examine future leads in sensorial ergonomics for vestibular spatial disorientation. This work reviews: 1) the visual ergonomics, 2) the vestibular countermeasures, 3) the auditory displays, 4) the somatosensory countermeasures, and, finally, 5) the multisensory displays. This review emphasizes the positive aspects of auditory and somatosensory countermeasures as well as multisensory devices. Even if some aspects such as sensory conflict and motion sickness need to be assessed, these countermeasures should be taken into consideration for ergonomics work in the future. However, a recent development in aviation might offer new and better perspectives: unmanned aerial vehicles. Unmanned aerial vehicles aim to go beyond the physiological boundaries of human sensorial systems and would allow for coping with spatial disorientation and motion sickness. Even if research is necessary to improve the interaction between machines and humans, this recent development might be incredibly useful for decreasing or even stopping vestibular spatial disorientation.

  7. Vestibular stimulation for management of premenstrual syndrome

    PubMed Central

    Johny, Minu; Kumar, Sai Sailesh; Rajagopalan, Archana; Mukkadan, Joseph Kurien

    2017-01-01

    Objectives: The present study was undertaken to observe the effectiveness of vestibular stimulation in the management of premenstrual syndrome (PMS). Materials and Methods: The present study was an experimental study; twenty female participants of age group 18–30 years were recruited in the present study. Conventional swing was used to administer vestibular stimulation. Variables were recorded before and after vestibular stimulation and compared. Results: Depression and stress scores are significantly decreased after 2 months of intervention. Anxiety scores decreased followed by vestibular stimulation. However, it is no statistically significant. Serum cortisol levels significantly decreased after 2 months of intervention. WHOQOL-BREF-transformed scores were not significantly changed followed by the intervention. However, psychological domain score (T2) and social relationships domain score (T3) were increased followed by intervention. Systolic blood pressure was significantly decreased after 2 months of intervention. No significant change was observed in diastolic pressure and pulse rate. Pain score was significantly decreased after 2 months of intervention. Mini mental status examination scores and spatial and verbal memory score were significantly improved followed by intervention. Conclusion: The present study provides preliminary evidence for implementing vestibular stimulation for management of PMS as a nonpharmacological therapy. Hence, we recommend further well-controlled, detailed studies in this area with higher sample size. PMID:28250680

  8. Longitudinal performance of an implantable vestibular prosthesis.

    PubMed

    Phillips, Christopher; Ling, Leo; Oxford, Trey; Nowack, Amy; Nie, Kaibao; Rubinstein, Jay T; Phillips, James O

    2015-04-01

    Loss of vestibular function may be treatable with an implantable vestibular prosthesis that stimulates semicircular canal afferents with biphasic pulse trains. Several studies have demonstrated short-term activation of the vestibulo-ocular reflex (VOR) with electrical stimulation. Fewer long-term studies have been restricted to small numbers of animals and stimulation designed to produce adaptive changes in the electrically elicited response. This study is the first large consecutive series of implanted rhesus macaque to be studied longitudinally using brief stimuli designed to limit adaptive changes in response, so that the efficacy of electrical activation can be studied over time, across surgeries, canals and animals. The implantation of a vestibular prosthesis in animals with intact vestibular end organs produces variable responses to electrical stimulation across canals and animals, which change in threshold for electrical activation of eye movements and in elicited slow phase velocities over time. These thresholds are consistently lower, and the slow phase velocities higher, than those obtained in human subjects. The changes do not appear to be correlated with changes in electrode impedance. The variability in response suggests that empirically derived transfer functions may be required to optimize the response of individual canals to a vestibular prosthesis, and that this function may need to be remapped over time. This article is part of a Special Issue entitled .

  9. Complications of Microsurgery of Vestibular Schwannoma

    PubMed Central

    Zvěřina, Eduard; Balogová, Zuzana; Skřivan, Jiří; Kraus, Josef; Syka, Josef; Chovanec, Martin

    2014-01-01

    Background. The aim of this study was to analyze complications of vestibular schwannoma (VS) microsurgery. Material and Methods. A retrospective study was performed in 333 patients with unilateral vestibular schwannoma indicated for surgical treatment between January 1997 and December 2012. Postoperative complications were assessed immediately after VS surgery as well as during outpatient followup. Results. In all 333 patients microsurgical vestibular schwannoma (Koos grade 1: 12, grade 2: 34, grade 3: 62, and grade 4: 225) removal was performed. The main neurological complication was facial nerve dysfunction. The intermediate and poor function (HB III–VI) was observed in 124 cases (45%) immediately after surgery and in 104 cases (33%) on the last followup. We encountered disordered vestibular compensation in 13%, permanent trigeminal nerve dysfunction in 1%, and transient lower cranial nerves (IX–XI) deficit in 6%. Nonneurological complications included CSF leakage in 63% (lateral/medial variant: 99/1%), headache in 9%, and intracerebral hemorrhage in 5%. We did not encounter any case of meningitis. Conclusions. Our study demonstrates that despite the benefits of advanced high-tech equipment, refined microsurgical instruments, and highly developed neuroimaging technologies, there are still various and significant complications associated with vestibular schwannomas microsurgery. PMID:24987677

  10. Stochastic thermodynamics

    NASA Astrophysics Data System (ADS)

    Eichhorn, Ralf; Aurell, Erik

    2014-04-01

    'Stochastic thermodynamics as a conceptual framework combines the stochastic energetics approach introduced a decade ago by Sekimoto [1] with the idea that entropy can consistently be assigned to a single fluctuating trajectory [2]'. This quote, taken from Udo Seifert's [3] 2008 review, nicely summarizes the basic ideas behind stochastic thermodynamics: for small systems, driven by external forces and in contact with a heat bath at a well-defined temperature, stochastic energetics [4] defines the exchanged work and heat along a single fluctuating trajectory and connects them to changes in the internal (system) energy by an energy balance analogous to the first law of thermodynamics. Additionally, providing a consistent definition of trajectory-wise entropy production gives rise to second-law-like relations and forms the basis for a 'stochastic thermodynamics' along individual fluctuating trajectories. In order to construct meaningful concepts of work, heat and entropy production for single trajectories, their definitions are based on the stochastic equations of motion modeling the physical system of interest. Because of this, they are valid even for systems that are prevented from equilibrating with the thermal environment by external driving forces (or other sources of non-equilibrium). In that way, the central notions of equilibrium thermodynamics, such as heat, work and entropy, are consistently extended to the non-equilibrium realm. In the (non-equilibrium) ensemble, the trajectory-wise quantities acquire distributions. General statements derived within stochastic thermodynamics typically refer to properties of these distributions, and are valid in the non-equilibrium regime even beyond the linear response. The extension of statistical mechanics and of exact thermodynamic statements to the non-equilibrium realm has been discussed from the early days of statistical mechanics more than 100 years ago. This debate culminated in the development of linear response

  11. VESTIBULAR SCHWANNOMA (ACOUSTIC NEUROMA) MIMICKING TEMPOROMANDIBULAR DISORDERS: A CASE REPORT

    PubMed Central

    Bisi, Maurício A.; Selaimen, Caio M. P.; Chaves, Karen D.; Bisi, Melissa C.; Grossi, Márcio L.

    2006-01-01

    Approximately 6 to 16% of patients with trigeminal neuralgia symptoms present intracranial tumors, the most common being the vestibular schwannoma (acoustic neuroma). Some symptoms reported by patients include hearing loss, tinnitus, headaches, vertigo and trigeminal disturbances. An increased muscle response in the surrounding head and neck musculature may also be observed, which mimics signs and symptoms of temporomandibular disorders. In these cases, magnetic resonance imaging (MRI) has proved to be a useful tool in tumor diagnosis. The differential diagnosis between myofascial and neuralgic pain is important, as both may present similar characteristics, while being of different origin, and demanding special treatment approaches. The purpose of this paper is to demonstrate the relationship among trigeminal neuralgia symptoms, intracranial tumors and temporomandibular dysfunction by presenting a clinical case. PMID:19089251

  12. Recovery of cochlear and vestibular function after labyrinthine haemorrhage.

    PubMed

    Araújo-Martins, José; Melo, Patrícia; Ribeiro, Cristóvão; Barros, Ezequiel

    2014-01-01

    Inner ear haemorrhage is a rare disorder with disabling symptoms. Prognosis is generally considered to be poor with essentially no chance of functional recovery. The most common aetiologies are related to blood dyscrasias, anticoagulant therapy or local trauma. The association with autoimmune diseases is exceptional. The authors report a case of sudden deafness with vertigo in a patient with rheumatoid arthritis, caused by labyrinthine haemorrhage. Clinical picture and progress of audiovestibular function are described along with imagiological features from magnetic resonance imaging. Inner ear haemorrhage is a rare disorder with disabling symptoms and poor prognosis. To the best of the authors' knowledge, this is the first case described with documented vestibular function recovery following labyrinthine haemorrhage.

  13. Optical nerve stimulation for a vestibular prosthesis

    NASA Astrophysics Data System (ADS)

    Harris, David M.; Bierer, Steven M.; Wells, Jonathon D.; Phillips, James O.

    2009-02-01

    Infrared Nerve Stimulation (INS) offers several advantages over electrical stimulation, including more precise spatial selectivity and improved surgical access. In this study, INS and electrical stimulation were compared in their ability to activate the vestibular branch of the VIIIth nerve, as a potential way to treat balance disorders. The superior and lateral canals of the vestibular system of Guinea pigs were identified and approached with the aid of precise 3-D reconstructions. A monopolar platinum stimulating electrode was positioned near the ampullae of the canals, and biphasic current pulses were used to stimulate vestibular evoked potentials and eye movements. Thresholds and input/output functions were measured for various stimulus conditions. A short pulsed diode laser (Capella, Lockheed Martin-Aculight, Inc., Bothell WA) was placed in the same anatomical position and various stimulus conditions were evaluated in their ability to evoke similar potentials and eye movements.

  14. QB1 - Stochastic Gene Regulation

    SciTech Connect

    Munsky, Brian

    2012-07-23

    Summaries of this presentation are: (1) Stochastic fluctuations or 'noise' is present in the cell - Random motion and competition between reactants, Low copy, quantization of reactants, Upstream processes; (2) Fluctuations may be very important - Cell-to-cell variability, Cell fate decisions (switches), Signal amplification or damping, stochastic resonances; and (3) Some tools are available to mode these - Kinetic Monte Carlo simulations (SSA and variants), Moment approximation methods, Finite State Projection. We will see how modeling these reactions can tell us more about the underlying processes of gene regulation.

  15. 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.

  16. Estimation of Optimum Stimulus Amplitude for Balance Training using Electrical Stimulation of the Vestibular System

    NASA Technical Reports Server (NTRS)

    Goel, R.; Rosenberg, M. J.; De Dios, Y. E.; Cohen, H. S.; Bloomberg, J. J.; Mulavara, A. P.

    2016-01-01

    Sensorimotor changes such as posture and gait instabilities can affect the functional performance of astronauts after gravitational transitions. Sensorimotor Adaptability (SA) training can help alleviate decrements on exposure to novel sensorimotor environments based on the concept of 'learning to learn' by exposure to varying sensory challenges during posture and locomotion tasks (Bloomberg 2015). Supra-threshold Stochastic Vestibular Stimulation (SVS) can be used to provide one of many challenges by disrupting vestibular inputs. In this scenario, the central nervous system can be trained to utilize veridical information from other sensory inputs, such as vision and somatosensory inputs, for posture and locomotion control. The minimum amplitude of SVS to simulate the effect of deterioration in vestibular inputs for preflight training or for evaluating vestibular contribution in functional tests in general, however, has not yet been identified. Few studies (MacDougall 2006; Dilda 2014) have used arbitrary but fixed maximum current amplitudes from 3 to 5 mA in the medio-lateral (ML) direction to disrupt balance function in healthy adults. Giving this high level of current amplitude to all the individuals has a risk of invoking side effects such as nausea and discomfort. The goal of this study was to determine the minimum SVS level that yields an equivalently degraded balance performance. Thirteen subjects stood on a compliant foam surface with their eyes closed and were instructed to maintain a stable upright stance. Measures of stability of the head, trunk, and whole body were quantified in the ML direction. Duration of time they could stand on the foam surface was also measured. The minimum SVS dosage was defined to be that level which significantly degraded balance performance such that any further increase in stimulation level did not lead to further balance degradation. The minimum SVS level was determined by performing linear fits on the performance variable

  17. Electrical vestibular stimuli to enhance vestibulo-motor output and improve subject comfort.

    PubMed

    Forbes, Patrick A; Dakin, Christopher J; Geers, Anoek M; Vlaar, Martijn P; Happee, Riender; Siegmund, Gunter P; Schouten, Alfred C; Blouin, Jean-Sébastien

    2014-01-01

    Electrical vestibular stimulation is often used to assess vestibulo-motor and postural responses in both clinical and research settings. Stochastic vestibular stimulation (SVS) is a recently established technique with many advantages over its square-wave counterpart; however, the evoked muscle responses remain relatively small. Although the vestibular-evoked responses can be enhanced by increasing the stimulus amplitude, subjects often perceive these higher intensity electrical stimuli as noxious or painful. Here, we developed multisine vestibular stimulation (MVS) signals that include precise frequency contributions to increase signal-to-noise ratios (SNR) of stimulus-evoked muscle and motor responses. Subjects were exposed to three different MVS stimuli to establish that: 1) MVS signals evoke equivalent vestibulo-motor responses compared to SVS while improving subject comfort and reducing experimentation time, 2) stimulus-evoked vestibulo-motor responses are reliably estimated as a linear system and 3) specific components of the cumulant density time domain vestibulo-motor responses can be targeted by controlling the frequency content of the input stimulus. Our results revealed that in comparison to SVS, MVS signals increased the SNR 3-6 times, reduced the minimum experimentation time by 85% and improved subjective measures of comfort by 20-80%. Vestibulo-motor responses measured using both EMG and force were not substantially affected by nonlinear distortions. In addition, by limiting the contribution of high frequencies within the MVS input stimulus, the magnitude of the medium latency time domain motor output response was increased by 58%. These results demonstrate that MVS stimuli can be designed to target and enhance vestibulo-motor output responses while simultaneously improving subject comfort, which should prove beneficial for both research and clinical applications.

  18. Physiological principles of vestibular function on earth and in space

    NASA Technical Reports Server (NTRS)

    Minor, L. B.

    1998-01-01

    Physiological mechanisms underlying vestibular function have important implications for our ability to understand, predict, and modify balance processes during and after spaceflight. The microgravity environment of space provides many unique opportunities for studying the effects of changes in gravitoinertial force on structure and function of the vestibular system. Investigations of basic vestibular physiology and of changes in reflexes occurring as a consequence of exposure to microgravity have important implications for diagnosis and treatment of vestibular disorders in human beings. This report reviews physiological principles underlying control of vestibular processes on earth and in space. Information is presented from a functional perspective with emphasis on signals arising from labyrinthine receptors. Changes induced by microgravity in linear acceleration detected by the vestibulo-ocular reflexes. Alterations of the functional requirements for postural control in space are described. Areas of direct correlation between studies of vestibular reflexes in microgravity and vestibular disorders in human beings are discussed.

  19. From ear to uncertainty: vestibular contributions to cognitive function

    PubMed Central

    Smith, Paul F.; Zheng, Yiwen

    2013-01-01

    In addition to the deficits in the vestibulo-ocular and vestibulo-spinal reflexes that occur following vestibular dysfunction, there is substantial evidence that vestibular loss also causes cognitive disorders, some of which may be due to the reflexive deficits and some of which are related to the role that ascending vestibular pathways to the limbic system and neocortex play in spatial orientation. In this review we summarize the evidence that vestibular loss causes cognitive disorders, especially spatial memory deficits, in animals and humans and critically evaluate the evidence that these deficits are not due to hearing loss, problems with motor control, oscillopsia or anxiety and depression. We review the evidence that vestibular lesions affect head direction and place cells as well as the emerging evidence that artificial activation of the vestibular system, using galvanic vestibular stimulation (GVS), can modulate cognitive function. PMID:24324413

  20. Interactions between Stress and Vestibular Compensation – A Review

    PubMed Central

    Saman, Yougan; Bamiou, D. E.; Gleeson, Michael; Dutia, Mayank B.

    2012-01-01

    Elevated levels of stress and anxiety often accompany vestibular dysfunction, while conversely complaints of dizziness and loss of balance are common in patients with panic and other anxiety disorders. The interactions between stress and vestibular function have been investigated both in animal models and in clinical studies. Evidence from animal studies indicates that vestibular symptoms are effective in activating the stress axis, and that the acute stress response is important in promoting compensatory synaptic and neuronal plasticity in the vestibular system and cerebellum. The role of stress in human vestibular disorders is complex, and definitive evidence is lacking. This article reviews the evidence from animal and clinical studies with a focus on the effects of stress on the central vestibular pathways and their role in the pathogenesis and management of human vestibular disorders. PMID:22866048

  1. Vestibular convergence patterns in vestibular nuclei neurons of alert primates.

    PubMed

    Dickman, J David; Angelaki, Dora E

    2002-12-01

    Sensory signal convergence is a fundamental and important aspect of brain function. Such convergence may often involve complex multidimensional interactions as those proposed for the processing of otolith and semicircular canal (SCC) information for the detection of translational head movements and the effective discrimination from physically congruent gravity signals. In the present study, we have examined the responses of primate rostral vestibular nuclei (VN) neurons that do not exhibit any eye movement-related activity using 0.5-Hz translational and three-dimensional (3D) rotational motion. Three distinct neural populations were identified. Approximately one-fourth of the cells exclusively encoded rotational movements (canal-only neurons) and were unresponsive to translation. The canal-only central neurons encoded head rotation in SCC coordinates, exhibited little orthogonal canal convergence, and were characterized with significantly higher sensitivities to rotation as compared to primary SCC afferents. Another fourth of the neurons modulated their firing rates during translation (otolith-only cells). During rotations, these neurons only responded when the axis of rotation was earth-horizontal and the head was changing orientation relative to gravity. The remaining one-half of VN neurons were sensitive to both rotations and translations (otolith + canal neurons). Unlike primary otolith afferents, however, central neurons often exhibited significant spatiotemporal (noncosine) tuning properties and a wide variety of response dynamics to translation. To characterize the pattern of SCC inputs to otolith + canal neurons, their rotational maximum sensitivity vectors were computed using exclusively responses during earth-vertical axis rotations (EVA). Maximum sensitivity vectors were distributed throughout the 3D space, suggesting strong convergence from multiple SCCs. These neurons were also tested with earth-horizontal axis rotations (EHA), which would activate

  2. Vestibular convergence patterns in vestibular nuclei neurons of alert primates

    NASA Technical Reports Server (NTRS)

    Dickman, J. David; Angelaki, Dora E.

    2002-01-01

    Sensory signal convergence is a fundamental and important aspect of brain function. Such convergence may often involve complex multidimensional interactions as those proposed for the processing of otolith and semicircular canal (SCC) information for the detection of translational head movements and the effective discrimination from physically congruent gravity signals. In the present study, we have examined the responses of primate rostral vestibular nuclei (VN) neurons that do not exhibit any eye movement-related activity using 0.5-Hz translational and three-dimensional (3D) rotational motion. Three distinct neural populations were identified. Approximately one-fourth of the cells exclusively encoded rotational movements (canal-only neurons) and were unresponsive to translation. The canal-only central neurons encoded head rotation in SCC coordinates, exhibited little orthogonal canal convergence, and were characterized with significantly higher sensitivities to rotation as compared to primary SCC afferents. Another fourth of the neurons modulated their firing rates during translation (otolith-only cells). During rotations, these neurons only responded when the axis of rotation was earth-horizontal and the head was changing orientation relative to gravity. The remaining one-half of VN neurons were sensitive to both rotations and translations (otolith + canal neurons). Unlike primary otolith afferents, however, central neurons often exhibited significant spatiotemporal (noncosine) tuning properties and a wide variety of response dynamics to translation. To characterize the pattern of SCC inputs to otolith + canal neurons, their rotational maximum sensitivity vectors were computed using exclusively responses during earth-vertical axis rotations (EVA). Maximum sensitivity vectors were distributed throughout the 3D space, suggesting strong convergence from multiple SCCs. These neurons were also tested with earth-horizontal axis rotations (EHA), which would activate

  3. Vestibular rehabilitation in elderly patients with central vestibular dysfunction: a prospective, randomized pilot study.

    PubMed

    Marioni, Gino; Fermo, Salvatore; Lionello, Marco; Fasanaro, Elena; Giacomelli, Luciano; Zanon, Stefania; Staffieri, Claudia; Dall'Igna, Franco; Manzato, Enzo; Staffieri, Alberto

    2013-12-01

    For the vestibular system, aging is associated with degenerated otoconia and loss of hair cells, vestibular afferents, and cells in the vestibular nuclei. Further neurodegenerative processes involve cortical, extrapyramidal motor, and cerebellar structures. Dizziness is quite common in the elderly, limiting their mobility and activities. The role of vestibular rehabilitation in these patients is controversial. The present prospective, randomized, preliminary investigation aimed to compare the effect of a 6-week posturography-assisted vestibular rehabilitation protocol (30 min a week) combined with a home-based exercise program (group A, 14 randomly assigned elderly patients) with the same home-based exercise program alone (group B, 14 randomly assigned elderly patients) for treating dizziness due to central vestibular dysfunction in elderly patients. The outcomes were analyzed using the 25-item Dizziness Handicap Inventory (DHI) and computerized posturography. After rehabilitation, group A scored significantly better in the DHI for the functional (p = 0.0016) and emotional (p = 0.01) domains and total score (p = 0.001); only the emotional domain improved significantly in group B (p = 0.038). Group A improved significantly in some posturographic parameters in the motor tests (reaction time, movement velocity, and endpoint excursion), while group B experienced more limited improvements. Our preliminary results with a program of posturography-assisted vestibular rehabilitation, and home-based exercises are more promising than with home-based exercises alone. A new study on a larger series of elderly patients with central vestibular dysfunctions is currently underway at Padova University, considering the effect of a protocol involving rehabilitation with computerized posturography alone and the relationship between outcomes and the duration of rehabilitation programs.

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

    PubMed

    Lacour, Michel; Bernard-Demanze, Laurence

    2014-01-01

    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.

  5. 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

  6. Vesibulotoxicity and Management of Vestibular Disorders

    ERIC Educational Resources Information Center

    Carey, John P.

    2005-01-01

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

  7. Genetics of Recurrent Vertigo and Vestibular Disorders

    PubMed Central

    Gazquez, Irene; Lopez-Escamez, Jose A

    2011-01-01

    We present recent advances in the genetics of recurrent vertigo, including familial episodic ataxias, migraneous vertigo, bilateral vestibular hypofunction and Meniere’s disease. Although several vestibular disorders are more common within families, the genetics of vestibulopathies is largely not known. Genetic loci and clinical features of familial episodic ataxias have been defined in linkage disequilibrium studies with mutations in neuronal genes KCNA1 and CACNA1A. Migrainous vertigo is a clinical disorder with a high comorbidity within families much more common in females with overlapping features with episodic ataxia and migraine. Bilateral vestibular hypofunction is a heterogeneous clinical group defined by episodes of vertigo leading to progressive loss of vestibular function which also can include migraine. Meniere’s disease is a clinical syndrome characterized by spontaneous episodes of recurrent vertigo, sensorineural hearing loss, tinnitus and aural fullness and familial Meniere’s disease in around 10-20% of cases. An international collaborative effort to define the clinical phenotype and recruiting patients with migrainous vertigo and Meniere’s disease is ongoing for genome-wide association studies. PMID:22379397

  8. Immunological Influences on the Vestibular System

    NASA Technical Reports Server (NTRS)

    Warchol, Mark E.

    2003-01-01

    The goals of this project were to examine the influence of immune signaling molecules on the survival and replacement of sensory hair cells in the vestibular organs. We have made considerable progress toward that goal, particularly in the characterization of mechanisms that underlie hair cell death.

  9. Perspectives in vestibular diagnostics and therapy

    PubMed Central

    Ernst, Arneborg

    2012-01-01

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

  10. Perspectives in vestibular diagnostics and therapy.

    PubMed

    Ernst, Arneborg

    2011-01-01

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

  11. Vestibular Efferent Activity in Squirrel Monkeys

    DTIC Science & Technology

    1990-10-01

    animals. We will stimulate the VIIIth nerves bilaterally to antidromically identify these neurons. Subsequently, we will identify sources of synaptic...system. We will record extracellularly in alert animals from the somata of antidromically identified efferent vestibular neurons to define the level of

  12. Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome: a slowly progressive disorder with stereotypical presentation.

    PubMed

    Cazzato, Daniele; Dalla Bella, Eleonora; Dacci, Patrizia; Mariotti, Caterina; Lauria, Giuseppe

    2016-02-01

    Cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) is a newly described condition with onset in adulthood, characterized by progressive balance impairment and sensory disturbances in the lower limbs, which can severely affect patients' quality of life. Its pathogenesis remains obscure and the diagnosis challenging. We described four patients complaining of slowly progressive gait unbalance and sensory disturbances at the feet followed, after a period ranging 2-6 years, by cerebellar dysfunction. All patients showed gait and limb ataxia, positive Romberg sign, cerebellar dysarthria, gaze-evoked nystagmus, absent deep tendon reflexes, and impaired vibratory sensation. Nerve conduction studies revealed axonal sensory neuropathy, brain magnetic resonance imaging showed cerebellar atrophy, and otoneurological investigation demonstrated bilateral vestibular areflexia with impaired vestibulo-ocular reflexes. The diagnosis of CANVAS should be suspected on clinical ground based on homogeneous course of symptoms and signs, and addressed by video-oculography eye movement recording.

  13. New Insights into Pathophysiology of Vestibular Migraine

    PubMed Central

    Espinosa-Sanchez, Juan M.; Lopez-Escamez, Jose A.

    2015-01-01

    Vestibular migraine (VM) is a common disorder in which genetic, epigenetic, and environmental factors probably contribute to its development. The pathophysiology of VM is unknown; nevertheless in the last few years, several studies are contributing to understand the neurophysiological pathways involved in VM. The current hypotheses are mostly based on the knowledge of migraine itself. The evidence of trigeminal innervation of the labyrinth vessels and the localization of vasoactive neuropeptides in the perivascular afferent terminals of these trigeminal fibers support the involvement of the trigemino-vascular system. The neurogenic inflammation triggered by activation of the trigeminal-vestibulocochlear reflex, with the subsequent inner ear plasma protein extravasation and the release of inflammatory mediators, can contribute to a sustained activation and sensitization of the trigeminal primary afferent neurons explaining VM symptoms. The reciprocal connections between brainstem vestibular nuclei and the structures that modulate trigeminal nociceptive inputs (rostral ventromedial medulla, ventrolateral periaqueductal gray, locus coeruleus, and nucleus raphe magnus) are critical to understand the pathophysiology of VM. Although cortical spreading depression can affect cortical areas involved in processing vestibular information, functional neuroimaging techniques suggest a dysmodulation in the multimodal sensory integration and processing of vestibular and nociceptive information, resulting from a vestibulo-thalamo-cortical dysfunction, as the pathogenic mechanism underlying VM. The elevated prevalence of VM suggests that multiple functional variants may confer a genetic susceptibility leading to a dysregulation of excitatory–inhibitory balance in brain structures involved in the processing of sensory information, vestibular inputs, and pain. The interactions among several functional and structural neural networks could explain the pathogenic mechanisms of VM

  14. 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

  15. Stochastic gravity

    NASA Astrophysics Data System (ADS)

    Ross, D. K.; Moreau, William

    1995-08-01

    We investigate stochastic gravity as a potentially fruitful avenue for studying quantum effects in gravity. Following the approach of stochastic electrodynamics ( sed), as a representation of the quantum gravity vacuum we construct a classical state of isotropic random gravitational radiation, expressed as a spin-2 field,h µυ (x), composed of plane waves of random phase on a flat spacetime manifold. Requiring Lorentz invariance leads to the result that the spectral composition function of the gravitational radiation,h(ω), must be proportional to 1/ω 2. The proportionality constant is determined by the Planck condition that the energy density consist ofħω/2 per normal mode, and this condition sets the amplitude scale of the random gravitational radiation at the order of the Planck length, giving a spectral composition functionh(ω) =√16πc 2Lp/ω2. As an application of stochastic gravity, we investigate the Davies-Unruh effect. We calculate the two-point correlation function (R iojo(Oτ-δτ/2)R kolo(O,τ+δτ/2)) of the measureable geodesic deviation tensor field,R iojo, for two situations: (i) at a point detector uniformly accelerating through the random gravitational radiation, and (ii) at an inertial detector in a heat bath of the random radiation at a finite temperature. We find that the two correlation functions agree to first order inaδτ/c provided that the temperature and acceleration satisfy the relationkT=ħa/2πc.

  16. Virtual Labyrinth model of vestibular afferent excitation via implanted electrodes – Validation and application to design of a multichannel vestibular prosthesis

    PubMed Central

    Hayden, Russell; Sawyer, Stacia; Frey, Eric; Mori, Susumu; Migliaccio, Americo A.; Della Santina, Charles C.

    2012-01-01

    To facilitate design of a multichannel vestibular prosthesis that can restore sensation to individuals with bilateral loss of vestibular hair cell function, we created a virtual labyrinth model. Model geometry was generated through 3-dimensional (3D) reconstruction of microMRI and microCT scans of normal chinchillas (Chinchilla lanigera) acquired with 30–48 μm and 12 μm voxels, respectively. Virtual electrodes were positioned based on anatomic landmarks, and the extracellular potential field during a current pulse was computed using finite element methods. Potential fields then served as inputs to stochastic, nonlinear dynamic models for each of 2415 vestibular afferent axons with spiking dynamics based on a modified Smith and Goldberg model incorporating parameters that varied with fiber location in the neuroepithelium. Action potential propagation was implemented by a well validated model of myelinated fibers. We tested the model by comparing predicted and actual 3D angular vestibulo-ocular reflex (aVOR) axes of eye rotation elicited by prosthetic stimuli. Actual responses were measured using 3D video-oculography. The model was individualized for each animal by placing virtual electrodes based on microCT localization of real electrodes. 3D eye rotation axes were predicted from the relative proportion of model axons excited within each of the three ampullary nerves. Multiple features observed empirically were observed as emergent properties of the model, including effects of active and return electrode position, stimulus amplitude and pulse waveform shape on target fiber recruitment and stimulation selectivity. The modeling procedure is partially automated and can be readily adapted to other species, including humans. PMID:21380738

  17. Corticosteroids and vestibular exercises in vestibular neuritis. Single-blind randomized clinical trial.

    PubMed

    Goudakos, John K; Markou, Konstantinos D; Psillas, George; Vital, Victor; Tsaligopoulos, Miltiadis

    2014-05-01

    IMPORTANCE The management of patients with unilateral acute vestibular neuritis (VN) has not been established to date. OBJECTIVE To compare the use of vestibular exercises vs corticosteroid therapy in the recovery of patients with acute VN. DESIGN, SETTING, AND PARTICIPANTS Prospective, single-blind, randomized clinical trial at a primary referral center. Among all patients with acute vertigo, those having VN were eligible for inclusion in the study. INTERVENTIONS Forty patients with acute VN were randomly assigned to perform vestibular exercises or to receive corticosteroid therapy. After a baseline examination, follow-up evaluations were performed at 1, 6, and 12 months. MAIN OUTCOMES AND MEASURES Efficacy outcomes included clinical, canal, and otolith recovery. Scores on the European Evaluation of Vertigo Scale and the Dizziness Handicap Inventory were used for the evaluation of clinical recovery. Findings of caloric irrigation and vestibular evoked myogenic potentials indicated canal and otolith improvement, respectively. RESULTS Comparing the 2 treatment groups, no statistically significant differences were found in clinical, canal, or otolith recovery. At the 6-month examination, the number of patients with complete disease resolution in the corticosteroids group was significantly higher than that in the vestibular exercises group. However, at the end of the follow-up period, 45%(9 of 20) of patients in the vestibular exercises group and 50% (10 of 20) of patients in the corticosteroids group had complete disease resolution (P > .05). CONCLUSIONS AND RELEVANCE Treating patients who have acute VN with vestibular exercises seems equivalently effective as treating them with corticosteroid therapy in clinical, caloric, and otolith recovery. Corticosteroid therapy seems to enhance earlier complete acute VN resolution, with no added benefit in the long-term prognosis.

  18. Early vestibular physical therapy rehabilitation for Meniere's disease.

    PubMed

    Gottshall, Kim R; Topp, Shelby G; Hoffer, Michael E

    2010-10-01

    Meniere disease includes symptoms of fluctuating hearing loss, tinnitus, and subjective ear fullness accompanied by episodic vertigo. Along with these symptoms, patients with chronic Meniere often develop symptoms of disequilibrium and unsteadiness that extend beyond the episodic attacks and contribute to the total disability and reduced quality of life attributed to the disease. Vestibular rehabilitation physical therapy has been used only after vestibular ablation has stabilized the vestibular loss, and for patients stably managed on medical therapy who exhibit no fluctuation in symptoms. This article reviews the data substantiating current applications of vestibular therapy, including improvements in subjective and objective balance outcome measures, and explores the possible extension of vestibular rehabilitation to treatment of patients exhibiting continued fluctuating vestibular loss.

  19. Diverse spatial reference frames of vestibular signals in parietal cortex

    PubMed Central

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

    2013-01-01

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

  20. Vestibular system: the many facets of a multimodal sense.

    PubMed

    Angelaki, Dora E; Cullen, Kathleen E

    2008-01-01

    Elegant sensory structures in the inner ear have evolved to measure head motion. These vestibular receptors consist of highly conserved semicircular canals and otolith organs. Unlike other senses, vestibular information in the central nervous system becomes immediately multisensory and multimodal. There is no overt, readily recognizable conscious sensation from these organs, yet vestibular signals contribute to a surprising range of brain functions, from the most automatic reflexes to spatial perception and motor coordination. Critical to these diverse, multimodal functions are multiple computationally intriguing levels of processing. For example, the need for multisensory integration necessitates vestibular representations in multiple reference frames. Proprioceptive-vestibular interactions, coupled with corollary discharge of a motor plan, allow the brain to distinguish actively generated from passive head movements. Finally, nonlinear interactions between otolith and canal signals allow the vestibular system to function as an inertial sensor and contribute critically to both navigation and spatial orientation.

  1. Pediatric vestibular evaluation: two children with sensorineural hearing loss.

    PubMed

    Valente, L Maureen; Goebel, Joel A; Sinks, Belinda

    2012-04-01

    These two cases illustrate several important areas of vestibular evaluation with children. The two case reports represent two children who display very different vestibular findings despite having significant sensorineural hearing loss. These case reports highlight that pediatric findings can differ significantly from adult findings, stressing the importance of comparing pediatric results with pediatric normative data. These two cases also highlight that vestibular techniques may successfully be adapted for use with hearing-impaired children. That is, rotary chair, computerized dynamic posturography, and vestibular evoked myogenic potentials can be adapted to use with children, including those who demonstrate significant sensorineural hearing loss. Although there is a paucity of research and clinical work in this area, some investigators (Eviatar and Eviatar, 1977; Buchman et al, 2004; Jacot et al, 2009) have reported very rapid recovery from pediatric vestibular deficits. However, it is important for audiologists to be aware that techniques may successfully be adapted for children and that many children should undergo thorough vestibular evaluation.

  2. 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.

  3. Understanding the links between vestibular and limbic systems regulating emotions

    PubMed Central

    Rajagopalan, Archana; Jinu, K. V.; Sailesh, Kumar Sai; Mishra, Soumya; Reddy, Udaya Kumar; Mukkadan, Joseph Kurien

    2017-01-01

    Vestibular system, which consists of structures in the inner ear and brainstem, plays a vital role is body balance and patient well-being. In recent years, modulating this system by vestibular stimulation techniques are reported to be effective in stress relief and possibly patient's emotional well-being. Emotions refer to an aroused state involving intense feeling, autonomic activation, and related change in behavior, which accompany many of our conscious experiences. The limbic system is primarily involved in the regulation of emotions. Considering the extensive networks between vestibular and limbic system, it is likely that vestibular stimulation techniques may be useful in influencing emotions. Hence, we review here, the possible mechanisms through which vestibular system can influence emotions and highlight the necessary knowledge gaps, which warrants further research to develop vestibular stimulation techniques as a means to treat health conditions associated with emotional disturbances. PMID:28250668

  4. The vestibular contribution to the head direction signal and navigation

    PubMed Central

    Yoder, Ryan M.; Taube, Jeffrey S.

    2014-01-01

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

  5. What is the most effective vestibular rehabilitation technique in patients with unilateral peripheral vestibular disorders?

    PubMed

    Rossi-Izquierdo, Marcos; Santos-Pérez, Sofia; Soto-Varela, Andrés

    2011-11-01

    Vestibular rehabilitation has been found to be effective and safe in patients with instability. There is insufficient evidence, however, for distinguishing between the efficacies of different rehabilitation techniques. The objective of this study is to verify whether there are differences between two instrumental vestibular rehabilitation techniques, computerised dynamic posturography (CDP) and optokinetic stimulation (OKN), in order to establish the optimal strategy for each patient. We conducted a prospective, comparative study of the two techniques (CDP and OKN) in patients with instability due to chronic unilateral peripheral vestibular disorder. We randomly included 12 patients in each group, performing the evaluation with the Dizziness Handicap Inventory and the CDP with the sensorial organisation test (SOT), rhythmic weight shift and limits of stability (LOS). We found a statistically significant improvement in both groups in average balance score according to the SOT. In the OKN group, however, improvement was greater in visual preference. The CDP group showed greater benefits in the visual and vestibular input and LOS. Patients with poor vestibular and visual input or with reduced LOS will benefit more from an exercise protocol with CDP. Patients with poor visual preference, however, are ideal candidates for rehabilitation with OKN.

  6. Ernst Mach on the vestibular organ 100 years ago

    NASA Technical Reports Server (NTRS)

    Henn, V.; Young, L. R.

    1975-01-01

    The paper reviews the contributions of Ernst Mach to vestibular research. His experiments, mainly psychophysical in nature, included measurements of threshold and investigation of the vestibular-visual interaction. Among his conclusions are that the adequate stimulus for the semicircular canals must be pressure, and that the sustained endolymph flow theory of Breuer (1874) and Crum Brown (1874) is erroneous. Excerpts are given of Mach's publications on vestibular functions.-

  7. Stochastic Cooling

    SciTech Connect

    Blaskiewicz, M.

    2011-01-01

    Stochastic Cooling was invented by Simon van der Meer and was demonstrated at the CERN ISR and ICE (Initial Cooling Experiment). Operational systems were developed at Fermilab and CERN. A complete theory of cooling of unbunched beams was developed, and was applied at CERN and Fermilab. Several new and existing rings employ coasting beam cooling. Bunched beam cooling was demonstrated in ICE and has been observed in several rings designed for coasting beam cooling. High energy bunched beams have proven more difficult. Signal suppression was achieved in the Tevatron, though operational cooling was not pursued at Fermilab. Longitudinal cooling was achieved in the RHIC collider. More recently a vertical cooling system in RHIC cooled both transverse dimensions via betatron coupling.

  8. Does impulse noise induce vestibular disturbances?

    PubMed

    Pyykkö, I; Aalto, H; Ylikoski, J

    1989-01-01

    The effect of impulse noise on postural stability was evaluated in 54 subjects from the Finnish army, who were suffering from acute hearing loss caused by exposure to firearms noise. For referents we used 20 non-exposed army recruits and 39 civilian volunteers. The effects of vision, pressoreceptor function and proprioception were stepwise excluded or altered, leaving mainly the vestibular guidance of postural control intact. Since the postural perturbation was fairly smooth during these instances we assume that the condition evaluates mainly the function of the otolith organs in guiding stance. We found no difference in any of the test conditions used, between normal controls, army controls and impulse noise exposed subjects. Furthermore, there was no dose response with body sway and severity of hearing loss. The results indicate that impulse noise may not be the cause of significant functional changes in the vestibular system that can account for noise-induced postural instability.

  9. Status of vestibular function after prolonged bedrest

    NASA Astrophysics Data System (ADS)

    Burgeat, M.; Toupet, M.; Loth, D.; Ingster, I.; Guell, A.; Coll, J.

    6 young, healthy, male volunteers were submitted to one week of head down (-4°) bedrest. This position simulates the cerebral hemodynamic conditions in weightlessness. Measurements of vestibular equilibrium and of oculomotor system function were made before and after the prolonged bedrest. Analysis of the results indicates that vestibular responses, as measured by the maximal speed of the slow phase of the provoked nystagmus (caloric and sinusoidal rotatory stimulations), are decreased after prolonged bedrest. This statistically significant diminution requires confirmation with a greater number of cases. The reflex conflicting or interacting with the cervico-ocular and optokinetic reflexes on the one hand and the foveal vision on the other, is one of several possible explanations for the observed changes.

  10. The vestibular system of the owl

    NASA Technical Reports Server (NTRS)

    Money, K. E.; Correia, M. J.

    1973-01-01

    Five owls were given vestibular examinations, and two of them were sacrificed to provide serial histological sections of the temporal bones. The owls exhibited a curious variability in the postrotatory head nystagmus following abrupt deceleration; sometimes a brisk nystagnus with direction opposite to that appropriate to the stimulus would occur promptly after deceleration. It was found also that owls can exhibit a remarkable head stability during angular movement of the body about any axis passing through the skull. The vestibular apparatus in the owl is larger than in man, and a prominent crista neglecta is present. The tectorial membrane, the cupula, and the otolithic membranes of the utricle, saccule, and lagena are all attached to surfaces in addition to the surfaces hearing hair cells. These attachments are very substantial in the utricular otolithic membrane and in the cupula.

  11. Vestibular activation of sympathetic nerve activity

    NASA Technical Reports Server (NTRS)

    Ray, C. A.; Carter, J. R.

    2003-01-01

    AIM: The vestibulosympathetic reflex refers to sympathetic nerve activation by the vestibular system. Animal studies indicate that the vestibular system assists in blood pressure regulation during orthostasis. Although human studies clearly demonstrate activation of muscle sympathetic nerve activity (MSNA) during engagement of the otolith organs, the role of the vestibulosympathetic reflex in maintaining blood pressure during orthostasis is not well-established. Examination of the vestibulosympathetic reflex with other cardiovascular reflexes indicates that it is a powerful and independent reflex. Ageing, which is associated with an increased risk for orthostatic hypotension, attenuates the vestibulosympathetic reflex. The attenuated reflex is associated with a reduction in arterial pressure. CONCLUSION: These findings suggest that the vestibulosympathetic reflex assists in blood pressure regulation in humans, but future studies examining this reflex in other orthostatically intolerant populations are necessary to address this hypothesis.

  12. Vestibular efferent neurons project to the flocculus

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    A bilateral projection from the vestibular efferent neurons, located dorsal to the genu of the facial nerve, to the cerebellar flocculus and ventral paraflocculus was demonstrated. Efferent neurons were double-labeled by the unilateral injections of separate retrograde tracers into the labyrinth and into the floccular and ventral parafloccular lobules. Efferent neurons were found with double retrograde tracer labeling both ipsilateral and contralateral to the sites of injection. No double labeling was found when using a fluorescent tracer with non-fluorescent tracers such as horseradish peroxidase (HRP) or biotinylated dextran amine (BDA), but large percentages of efferent neurons were found to be double labeled when using two fluorescent substances including: fluorogold, microruby dextran amine, or rhodamine labeled latex beads. These data suggest a potential role for vestibular efferent neurons in modulating the dynamics of the vestibulo-ocular reflex (VOR) during normal and adaptive conditions.

  13. [Unusual clinical presentations of vestibular schwannomas].

    PubMed

    Coca Pelaz, Andrés; Rodrigo, Juan P; Llorente, José L; Gómez, Justo R; Suárez, Carlos

    2008-04-01

    The aim of this study is evaluate the unusual ways of initial presentation of the vestibular schwannomas. We performed a retrospective study of the patients who underwent resection of acoustic neuromas on our service, including for analysis only the cases which initial symptom was not the hearing loss. Tumor size, localization, clinical presentation, and age of the patients were considered. Nine patients present with atypical symptoms. The most common complain in this group were facial paresthesias (22,2 %). None of them complained about other otological symptoms. A significant group of patients did not present with the otological symptoms classically associated with vestibular schwannoma. Clinical knowledge of these kinds of symptoms may lead to earlier detection of these lesions.

  14. Experiment M131. Human vestibular function

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  15. Vestibular Schwannoma Atypically Invading Temporal Bone

    PubMed Central

    Park, Soo Jeong; Yang, Na-Rae

    2015-01-01

    Vestibular schwannoma (VS) usually present the widening of internal auditory canal (IAC), and these bony changes are typically limited to IAC, not extend to temporal bone. Temporal bone invasion by VS is extremely rare. We report 51-year-old man who revealed temporal bone destruction beyond IAC by unilateral VS. The bony destruction extended anteriorly to the carotid canal and inferiorly to the jugular foramen. On histopathologic examination, the tumor showed typical benign schwannoma and did not show any unusual vascularity or malignant feature. Facial nerve was severely compressed and distorted by tumor, which unevenly eroded temporal bone in surgical field. Vestibular schwannoma with atypical invasion of temporal bone can be successfully treated with combined translabyrinthine and lateral suboccipiral approach without facial nerve dysfunction. Early detection and careful dissection of facial nerve with intraoperative monitoring should be considered during operation due to severe adhesion and distortion of facial nerve by tumor and eroded temporal bone. PMID:25932298

  16. Vestibular-ocular accommodation reflex in man

    NASA Technical Reports Server (NTRS)

    Clark, B.; Randle, R. J.; Stewart, J. D.

    1975-01-01

    Stimulation of the vestibular system by angular acceleration produces widespread sensory and motor effects. The present paper studies a motor effect which has not been reported in the literature, i.e., the influence of rotary acceleration of the body on ocular accommodation. The accommodation of 10 young men was recorded before and after a high-level deceleration to zero velocity following 30 sec of rotating. Accommodation was recorded continuously on an infrared optometer for 110 sec under two conditions: while the subjects observed a target set at the far point, and while they viewed the same target through a 0.3-mm pinhole. Stimulation by high-level rotary deceleration produced positive accommodation or a pseudomyopia under both conditions, but the positive accommodation was substantially greater and lasted much longer during fixation through the pinhole. It is hypothesized that this increase in accommodation is a result of a vestibular-ocular accommodation reflex.

  17. 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.

  18. What is the minimal vestibular function required for compensation?

    NASA Technical Reports Server (NTRS)

    Black, F. O.; Wade, S. W.; Nashner, L. M.

    1996-01-01

    Living with an uncompensated, abnormal vestibular system requires oppressive modification of life style and often prevents return to work and activities of daily living. Patients with vestibular abnormalities were studied to determine the minimal residual vestibular function required to achieve compensation. Three groups of patients with (a) complete unilateral loss of vestibular function with normal horizontal canal-vestibulo-ocular (HCVOR) function in the opposite ear, (b) complete unilateral loss with abnormal HCVOR function in the opposite ear, and (c) bilateral reduction of vestibular function from aminoglycoside toxicity underwent vestibuloocular (VOR), optokinetic (OKN), visual-VOR (VVOR), and computerized dynamic posturography (CDP) tests before and after therapeutic procedures. Results suggest that a minimal VOR response amplitude must be present for compensation of VVOR function to occur. The roles of VOR and OKN phase shifts in vestibular compensation are more complicated and require further study. Compensation of vestibulospinal function does not necessarily accompany VOR or VVOR compensation. Ascending and descending vestibular compensatory mechanisms may involve different spatial sensory inputs. Results of these studies have important implications for the diagnosis and treatment of patients with vestibular disorders, including selection and monitoring of patients for therapeutic regimens such as vestibular nerve section and streptomycin therapy.

  19. Task, muscle and frequency dependent vestibular control of posture

    PubMed Central

    Forbes, Patrick A.; Siegmund, Gunter P.; Schouten, Alfred C.; Blouin, Jean-Sébastien

    2015-01-01

    The vestibular system is crucial for postural control; however there are considerable differences in the task dependence and frequency response of vestibular reflexes in appendicular and axial muscles. For example, vestibular reflexes are only evoked in appendicular muscles when vestibular information is relevant to postural control, while in neck muscles they are maintained regardless of the requirement to maintain head on trunk balance. Recent investigations have also shown that the bandwidth of vestibular input on neck muscles is much broader than appendicular muscles (up to a factor of 3). This result challenges the notion that vestibular reflexes only contribute to postural control across the behavioral and physiological frequency range of the vestibular organ (i.e., 0–20 Hz). In this review, we explore and integrate these task-, muscle- and frequency-related differences in the vestibular system’s contribution to posture, and propose that the human nervous system has adapted vestibular signals to match the mechanical properties of the system that each group of muscles controls. PMID:25620919

  20. Acute peripheral vestibular deficit increases redundancy in random number generation.

    PubMed

    Moser, Ivan; Vibert, Dominique; Caversaccio, Marco D; Mast, Fred W

    2017-02-01

    Unilateral peripheral vestibular deficit leads to broad cognitive difficulties and biases in spatial orientation. More specifically, vestibular patients typically show a spatial bias toward their affected ear in the subjective visual vertical, head and trunk orientation, fall tendency, and walking trajectory. By means of a random number generation task, we set out to investigate how an acute peripheral vestibular deficit affects the mental representation of numbers in space. Furthermore, the random number generation task allowed us to test if patients with peripheral vestibular deficit show evidence of impaired executive functions while keeping the head straight and while performing active head turns. Previous research using galvanic vestibular stimulation in healthy people has shown no effects on number space, but revealed increased redundancy of the generated numbers. Other studies reported a spatial bias in number representation during active and passive head turns. In this experiment, we tested 43 patients with acute vestibular neuritis (18 patients with left-sided and 25 with right-sided vestibular deficit) and 28 age-matched healthy controls. We found no bias in number space in patients with peripheral vestibular deficit but showed increased redundancy in patients during active head turns. Patients showed worse performance in generating sequences of random numbers, which indicates a deficit in the updating component of executive functions. We argue that RNG is a promising candidate for a time- and cost-effective assessment of executive functions in patients suffering from a peripheral vestibular deficit.

  1. Inferior vestibular neuritis in a fighter pilot: a case report.

    PubMed

    Xie, Su Jiang; Jia, Hong Bo; Xu, Po; Zheng, Ying Juan

    2013-06-01

    Spatial disorientation in airplane pilots is a leading factor in many fatal flying accidents. Spatial orientation is the product of integrative inputs from the proprioceptive, vestibular, and visual systems. One condition that can lead to sudden pilot incapacitation in flight is vestibular neuritis. Vestibular neuritis is commonly diagnosed by a finding of unilateral vestibular failure, such as a loss of caloric response. However, because caloric response testing reflects the function of only the superior part of the vestibular nerve, it cannot detect cases of neuritis in only the inferior part of the nerve. We describe the case of a Chinese naval command fighter pilot who exhibited symptoms suggestive of vestibular neuritis but whose caloric response test results were normal. Further testing showed a unilateral loss of vestibular evoked myogenic potentials (VEMPs). We believe that this pilot had pure inferior nerve vestibular neuritis. VEMP testing plays a major role in the diagnosis of inferior nerve vestibular neuritis in pilots. We also discuss this issue in terms of aeromedical concerns.

  2. Periosteal Pedicle Flap Harvested during Vestibular Extension for Root Coverage

    PubMed Central

    Kumar, Shubham; Gupta, Krishna Kumar; Agrawal, Rahul; Srivastava, Pratima; Soni, Shalabh

    2015-01-01

    Root exposure along with inadequate vestibular depth is a common clinical finding. Treatment option includes many techniques to treat such defects for obtaining predictable root coverage. Normally, the vestibular depth is increased first followed by a second surgery for root coverage. The present case report describes a single-stage technique for vestibular extension and root coverage in a single tooth by using the Periosteal Pedicle Flap (PPF). This technique involves no donor site morbidity and allows for reflection of sufficient amount of periosteal flap tissue with its own blood supply at the surgical site, thus increasing the chances of success of root coverage with simultaneous increase in vestibular depth. PMID:26788377

  3. Stimulus Processing in Vestibular Hair Cells

    DTIC Science & Technology

    1990-01-03

    Preliminary results reveal that in some cells, the currents elicited by voltage steps are qualitatively similar to those previously described in frog ...rather than in the artificial perilymph used for the frog saccules. In some experiments individual hair cells were stimulated by moving their hair bundles...postsynaptic potentials alone. (2) Whole-cell current recording from isolated vestibular hair cells Hair cells were isolated from frog saccules and from rat

  4. Herpes encephalitis preceded by ipsilateral vestibular neuronitis.

    PubMed

    Philpot, Stephen J; Archer, John S

    2005-11-01

    A 74-year-old woman developed vertigo and jerk nystagmus to the left with normal cerebral imaging. Three days later she developed fever, altered mental state and left medial temporal lobe hypodensity, confirmed on lumbar puncture to be due to herpes simplex type 1 encephalitis. We propose that the patient had vestibular neuronitis caused by HSV-1 that progressed to ipsilateral temporal lobe encephalitis.

  5. Norman Thagard Explains the Microgravity Vestibular Investigation

    NASA Technical Reports Server (NTRS)

    1992-01-01

    In this video, astronaut Norman Thagard explains how he and his fellow STS-42 crew mates interacted with the rotator chair for the Microgravity Vestibular Investigations (MVI) onboard the International Microgravity Laboratory in July 1992. In the MVI, researchers from Canada, the United States, and other countries examined the effects of orbital flight on the human orientation system to obtain a better understanding of the mechanisms of adaptation to orbit.

  6. Cognitive requirements for vestibular and ocular motor processing in healthy adults and patients with unilateral vestibular lesions.

    PubMed

    Talkowski, M E; Redfern, M S; Jennings, J R; Furman, J M

    2005-09-01

    This study investigated the role of cognition in the vestibulo-ocular reflex (VOR) and ocular pursuit using a dual-task paradigm in patients with unilateral peripheral vestibular loss and healthy adults. We hypothesized that cognitive resources are involved in successful processing and integration of vestibular and ocular motor sensory information, and this requirement would be greater in patients with vestibular dysfunction. Sixteen well-compensated patients with surgically confirmed absent unilateral peripheral vestibular function and 16 healthy age- and sex-matched controls underwent seven combinations of vestibular-only, visual-only, and visual-vestibular stimuli while performing three different information processing tasks. Visual-vestibular stimuli included a semicircular canal and an otolith stimulus provided through seated chair rotations; fixation on a laser target and sinusoidal smooth pursuit while still; and fixation on a head-fixed laser target during chair rotations. The information processing tasks were three different auditory reaction time (RT) tasks: (1) simple RT, (2) disjunctive RT, and (3) choice RT. Our results showed increases in RTs in both patients and controls under all vestibular-only stimulation conditions and during ocular pursuit. Patients showed greater increases in RTs during vestibular stimulation and the more complex disjunctive and choice RT tasks. No differences between the groups were found during the visual-only or visual-vestibular interaction conditions. These results reveal interference between vestibulo-ocular processing and a concurrent RT task, suggesting that the VOR and the ocular motor system are dependent upon cognitive resources to some extent, and thus, are not fully automatic systems. We speculate that this interference with cognition occurs as a result of the sensory integration required for resolving inputs from multiple sensory streams. The particularly large decrement in information processing task performance

  7. Vestibular compensation and orientation during locomotion

    NASA Technical Reports Server (NTRS)

    Raphan, T.; Imai, T.; Moore, S. T.; Cohen, B.

    2001-01-01

    Body, head, and eye movements were studied in three dimensions while walking and turning to determine the role of the vestibular system in directing gaze and maintaining spatial orientation. The body, head, and eyes were represented as three-dimensional coordinate frames, and the movement of these frames was related to a trajectory frame that described the motion of the body on a terrestrial plane. The axis-angle of the body, head, and eye rotation were then compared to the axis-angle of the rotation of the gravitoinertial acceleration (GIA). We inferred the role of the vestibular system during locomotion and the contributions of the VCR and VOR by examining the interrelationship between these coordinate frames. Straight walking induced head and eye rotations in a compensatory manner to the linear accelerations, maintaining head pointing and gaze along the direction of forward motion. Turning generated a combination of compensation and orientation responses. The head leads and steers the turn while the eyes compensate to maintain stable horizontal gaze in space. Saccades shift horizontal gaze as the turn is executed. The head pitches, as during straight walking. It also rolls so that the head tends to align with the orientation of the GIA. Head orientation changes anticipate orientation changes of the GIA. Eye orientation follows the changes in GIA orientation so that the net orientation gaze is closer to the orientation of the GIA. The study indicates that the vestibular system utilizes compensatory and orienting mechanisms to stabilize spatial orientation and gaze during walking and turning.

  8. Allometry in vestibular responses of anurans

    NASA Astrophysics Data System (ADS)

    Yamashita, M.; Naitoh, T.; Kashiwagi, A.; Kondo, Y.; Wassersug, R. J.

    1999-01-01

    Frogs and toads turn either their heads or bodies opposite to angular accelerations applied around the yaw axis. Thresholds exist for the minimum angular acceleration that induces this vestibulomotor response in individual frogs. These thresholds were recorded for several anuran species that cover a broad range of sizes and life styles. Interspecific variation in the magnitude of the thresholds, which correlated with the ecology and behavior of the species, was documented. Also an allometric relationship was observed between this threshold and body size; the larger the frog, the lower the threshold. In many species, the threshold value for reflexive vestibulomotor responses to angular acceleration was proportional to the -0.4 (+/-0.2) power of body mass. Physical dimensions of the semicircular canals determine, in part, vestibular sensitivity to angular acceleration. Hence changes with growth in the semicircular canals are believed to contribute to the slope of -0.4. The biological significance of this allometry in vestibular responses is discussed and compared to trends in vestibular sensitivity and semicircular canal morphology of other vertebrate classes.

  9. Radiotherapy for Vestibular Schwannomas: A Critical Review

    SciTech Connect

    Murphy, Erin S.; 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 to >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.

  10. Audiovestibular Function Deficits in Vestibular Schwannoma

    PubMed Central

    2016-01-01

    Introduction. Vestibular schwannomas (VS) are benign tumours of the vestibular nerve and can lead to hearing loss, tinnitus, vertigo, facial palsy, and brainstem compression. Audiovestibular diagnostic tests are essential for detection and treatment planning. Methods. Medline was used to perform a systematic literature review with regard to how audiovestibular test parameters correlate with symptoms, tumour size, and tumour location. Results. The auditory brainstem response can be used to diagnose retrocochlear lesions caused by VS. Since hearing loss correlates poorly with tumour size, a retrocochlear lesion is probably not the only cause for hearing loss. Also cochlear mechanisms seem to play a role. This can be revealed by abnormal otoacoustic emissions, despite normal ABR and new MRI techniques which have demonstrated endolymphatic hydrops of the inner ear. Caloric and head impulse tests show frequency specific dynamics and vestibular evoked myogenic potentials may help to identify the location of the tumour regarding the involved nerve parts. Conclusion. In order to preserve audiovestibular function in VS, it is important to stop the growth of the tumour and to avoid degenerative changes in the inner ear. A detailed neurotological workup helps to diagnose VS of all sizes and can also provide useful prognostic information. PMID:27747231

  11. Assessment of vestibular function by videonystagmoscopy.

    PubMed

    Vitte, E; Sémont, A

    1995-01-01

    Videonystagmoscopy has been used to subjectively observe the responses of the vestibular system in a population of patients with vestibular deficits. These results were compared with those of a control group of healthy, age-matched volunteers. The videonystagmoscopy device is made of one or two CCD cameras mounted on lightproof goggles, allowing a subjective observation of ocular movements on a video monitor. The eye movements, as well as the position of the head in space, can be recorded on videotape. The eyes are illuminated by infrared light emitting diodes placed on each side of the camera lens. The subjects are seated on a manually driven Barany chair. Subjects went through a protocol of passive roll head tilt on each side, followed by a slow, whole body rotation of 180 degrees amplitude, clockwise and counterclockwise, and then a head shaking test (HST). The eyes were subjectively observed, and we focussed on: torsional eye movements during head tilt, nystagmus when the rotation had stopped, and nystagmus induced by HST. With this simple and noninvasive examining procedure, screening of vestibular function at the bedside or during E.N.T. clinical investigations is possible.

  12. Value of the video head impulse test in assessing vestibular deficits following vestibular neuritis.

    PubMed

    Bartolomeo, Mickael; Biboulet, Roselyne; Pierre, Guillemette; Mondain, Michel; Uziel, Alain; Venail, Frederic

    2014-04-01

    To evaluate the performance of the video head impulse test (VHIT) in assessing vestibular deficit in vestibular neuritis. Test validation study was conducted in Tertiary referral center. Twenty-nine patients, referred for vestibular neuritis between October 2009 and March 2012, were included. We recorded age, gender, values of caloric deficit (caloric testing), and deficits in semicircular function (VHIT) at initial presentation and at the follow-up visit (1-3 months). Multivariate linear regression analysis was performed to determine variables associated with values of caloric testing at the follow-up visit. Diagnostic values of VHIT were compared with caloric testing data using the receiver-operating characteristic (ROC) curve and subsequent statistical analysis. At the follow-up visit, complete recovery occurred in 31% of cases according to caloric evaluation, and VHIT normalized in 51.8%. Multivariate regression showed that a higher caloric deficit at the follow-up visit was associated with elevated age (p = 0.012) and high caloric deficit at initial presentation (p = 0.042). A lower caloric deficit was associated with normal VHIT results at the follow-up visit (p < 0.001). The ROC curve showed that specificity and sensitivity of VHIT were 100% when the caloric deficit was respectively lower than 40% or higher than 62.5%. At the caloric testing value of 30%, specificity was 100%, sensitivity 68.84%, positive predictive value 100% and negative predictive value 62.5%. VHIT is a fast, convenient and specific test to detect vestibular deficits in vestibular neuritis. However, VHIT lacks sensitivity by comparison with caloric testing, especially for moderate vestibular lesions.

  13. 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.

  14. 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

  15. Otolith-Canal Convergence in Vestibular Nuclei Neurons

    NASA Technical Reports Server (NTRS)

    Dickman, J. David

    1996-01-01

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

  16. 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

  17. Caloric Vestibular Stimulation Reduces Pain and Somatoparaphrenia in a Severe Chronic Central Post-Stroke Pain Patient: A Case Study

    PubMed Central

    2016-01-01

    Central post-stroke pain is a neuropathic syndrome characterized by intolerable contralesional pain and, in rare cases, somatic delusions. To date, there is limited evidence for the effective treatments of this disease. Here we used caloric vestibular stimulation to reduce pain and somatoparaphrenia in a 57-year-old woman suffering from central post-stroke pain. Resting-state functional magnetic resonance imaging was used to assess the neurological effects of this treatment. Following vestibular stimulation we observed impressive improvements in motor skills, pain, and somatic delusions. In the functional connectivity study before the vestibular stimulation, we observed differences in the patient’s left thalamus functional connectivity, with respect to the thalamus connectivity of a control group (N = 20), in the bilateral cingulate cortex and left insula. After the caloric stimulation, the left thalamus functional connectivity with these regions, which are known to be involved in the cortical response to pain, disappeared as in the control group. The beneficial use of vestibular stimulation in the reduction of pain and somatic delusion in a CPSP patient is now documented by behavioral and imaging data. This evidence can be applied to theoretical models of pain and body delusions. PMID:27028404

  18. Caloric Vestibular Stimulation Reduces Pain and Somatoparaphrenia in a Severe Chronic Central Post-Stroke Pain Patient: A Case Study.

    PubMed

    Spitoni, Grazia Fernanda; Pireddu, Giorgio; Galati, Gaspare; Sulpizio, Valentina; Paolucci, Stefano; Pizzamiglio, Luigi

    2016-01-01

    Central post-stroke pain is a neuropathic syndrome characterized by intolerable contralesional pain and, in rare cases, somatic delusions. To date, there is limited evidence for the effective treatments of this disease. Here we used caloric vestibular stimulation to reduce pain and somatoparaphrenia in a 57-year-old woman suffering from central post-stroke pain. Resting-state functional magnetic resonance imaging was used to assess the neurological effects of this treatment. Following vestibular stimulation we observed impressive improvements in motor skills, pain, and somatic delusions. In the functional connectivity study before the vestibular stimulation, we observed differences in the patient's left thalamus functional connectivity, with respect to the thalamus connectivity of a control group (N = 20), in the bilateral cingulate cortex and left insula. After the caloric stimulation, the left thalamus functional connectivity with these regions, which are known to be involved in the cortical response to pain, disappeared as in the control group. The beneficial use of vestibular stimulation in the reduction of pain and somatic delusion in a CPSP patient is now documented by behavioral and imaging data. This evidence can be applied to theoretical models of pain and body delusions.

  19. Stochastic Physicochemical Dynamics

    NASA Astrophysics Data System (ADS)

    Tsekov, R.

    2001-02-01

    fluctuations. The range of validity of the Boltzmann-Einstein principle is also discussed and a generalized alternative is proposed. Both expressions coincide in the small fluctuation limit, providing a normal distribution density. Fluctuation Stability of Thin Liquid Films: Memory effect of Brownian motion in an incompressible fluid is studied. The reasoning is based on the Mori-Zwanzig formalism and a new formulation of the Langevin force as a result of collisions between an effective and the Brownian particles. Thus, the stochastic force autocorrelation function with finite dispersion and the corresponding Brownian particle velocity autocorrelation function are obtained. It is demonstrated that the dynamic structure is very important for the rate of drainage of a thin liquid film and it can be effectively taken into account by a dynamic fractal dimension. It is shown that the latter is a powerful tool for description of the film drainage and classifies all the known results from the literature. The obtained general expression for the thinning rate is a heuristic one and predicts variety of drainage models, which are even difficult to simulate in practice. It is a typical example of a scaling law, which explains the origin of the complicate dependence of the thinning rate on the film radius. On the basis of the theory of stochastic processes the evolution of the spatial correlation function of the surface waves on a thin liquid film as well as the corresponding root mean square amplitude A(t) and number of uncorrelated subdomains N(t) are obtained. A formulation of the life time of unstable nonthinning films is proposed, based on the evolution of A and N. It is shown that the presence of uncorrelated subdomains shortens the life time of the film. Some numerical results for A(t) and N(t) at different film thicknesses h and areas S, are demonstrated, taking into account only van der Waals and capillary forces. Resonant Diffusion in Molecular Solid Structures: A new approach to

  20. Mechanical Autonomous Stochastic Heat Engine.

    PubMed

    Serra-Garcia, Marc; Foehr, André; Molerón, Miguel; Lydon, Joseph; Chong, Christopher; Daraio, Chiara

    2016-07-01

    Stochastic heat engines are devices that generate work from random thermal motion using a small number of highly fluctuating degrees of freedom. Proposals for such devices have existed for more than a century and include the Maxwell demon and the Feynman ratchet. Only recently have they been demonstrated experimentally, using, e.g., thermal cycles implemented in optical traps. However, recent experimental demonstrations of classical stochastic heat engines are nonautonomous, since they require an external control system that prescribes a heating and cooling cycle and consume more energy than they produce. We present a heat engine consisting of three coupled mechanical resonators (two ribbons and a cantilever) subject to a stochastic drive. The engine uses geometric nonlinearities in the resonating ribbons to autonomously convert a random excitation into a low-entropy, nonpassive oscillation of the cantilever. The engine presents the anomalous heat transport property of negative thermal conductivity, consisting in the ability to passively transfer energy from a cold reservoir to a hot reservoir.

  1. Mechanical Autonomous Stochastic Heat Engine

    NASA Astrophysics Data System (ADS)

    Serra-Garcia, Marc; Foehr, André; Molerón, Miguel; Lydon, Joseph; Chong, Christopher; Daraio, Chiara

    2016-07-01

    Stochastic heat engines are devices that generate work from random thermal motion using a small number of highly fluctuating degrees of freedom. Proposals for such devices have existed for more than a century and include the Maxwell demon and the Feynman ratchet. Only recently have they been demonstrated experimentally, using, e.g., thermal cycles implemented in optical traps. However, recent experimental demonstrations of classical stochastic heat engines are nonautonomous, since they require an external control system that prescribes a heating and cooling cycle and consume more energy than they produce. We present a heat engine consisting of three coupled mechanical resonators (two ribbons and a cantilever) subject to a stochastic drive. The engine uses geometric nonlinearities in the resonating ribbons to autonomously convert a random excitation into a low-entropy, nonpassive oscillation of the cantilever. The engine presents the anomalous heat transport property of negative thermal conductivity, consisting in the ability to passively transfer energy from a cold reservoir to a hot reservoir.

  2. Body ownership and embodiment: vestibular and multisensory mechanisms.

    PubMed

    Lopez, C; Halje, P; Blanke, O

    2008-06-01

    Body ownership and embodiment are two fundamental mechanisms of self-consciousness. The present article reviews neurological data about paroxysmal illusions during which body ownership and embodiment are affected differentially: autoscopic phenomena (out-of-body experience, heautoscopy, autoscopic hallucination, feeling-of-a-presence) and the room tilt illusion. We suggest that autoscopic phenomena and room tilt illusion are related to different types of failures to integrate body-related information (vestibular, proprioceptive and tactile cues) in addition to a mismatch between vestibular and visual references. In these patients, altered body ownership and embodiment has been shown to occur due to pathological activity at the temporoparietal junction and other vestibular-related areas arguing for a key importance of vestibular processing. We also review the possibilities of manipulating body ownership and embodiment in healthy subjects through exposition to weightlessness as well as caloric and galvanic stimulation of the peripheral vestibular apparatus. In healthy subjects, disturbed self-processing might be related to interference of vestibular stimulation with vestibular cortex leading to disintegration of bodily information and altered body ownership and embodiment. We finally propose a differential contribution of the vestibular cortical areas to the different forms of altered body ownership and embodiment.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Tinnitus, Oscillopsia, and Hyperventilation-Induced Nystagmus: Vestibular Paroxysmia

    PubMed Central

    Ward, Bryan K; Gold, Daniel R

    2016-01-01

    Vestibular paroxysmia is the name given to vascular compression of the vestibulocochlear nerve. Substantial evidence has been discovered in support of vascular compression of the trigeminal nerve as the etiology for trigeminal neuralgia, and effective therapies have been targeted to address this pathophysiology. Perhaps due to the common and often vaguely-described symptoms of dizziness and tinnitus, vascular compression of the vestibulocochlear nerve as a cause of symptoms has remained controversial. Recent clinical studies, however, have better defined diagnostic criteria for vestibular paroxysmia. In this report we discuss a case of vestibular paroxysmia, highlighting some findings of the condition that also uniquely separate it from other more common vestibular disorders. Finally, we discuss current clinical management of vestibular paroxysmia. PMID:27158666

  8. Development and regeneration of vestibular hair cells in mammals.

    PubMed

    Burns, Joseph C; Stone, Jennifer S

    2016-11-15

    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.

  9. A vestibular sensation: probabilistic approaches to spatial perception.

    PubMed

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

    2009-11-25

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

  10. An electronic prosthesis mimicking the dynamic vestibular function.

    PubMed

    Shkel, Andrei M; Zeng, Fan-Gang

    2006-01-01

    This paper presents a functional architecture, system level design, and electronic evaluation of a unilateral vestibular prosthesis. The sensing unit of the prosthesis is a custom-designed one-axis micro-electromechanical system (MEMS) gyroscope. Similar to the natural semicircular canal, the MEMS gyroscope senses angular motion of the head and generates voltages proportional to the corresponding angular acceleration. The voltage is then converted into electric current pulses according to the physiological data relating angular acceleration to the spike count in the vestibular nerve. The current pulses can be delivered to stimulate the corresponding vestibular nerve branch. Electronic properties of the vestibular prosthesis prototype have been systematically evaluated and found to meet the design specifications. A unique feature of the present vestibular implant prototype is the scalability: the sensing unit, pulse generator, and the current source can be potentially implemented on a single chip using integrated MEMS technology.

  11. How vestibular stimulation interacts with illusory hand ownership.

    PubMed

    Lopez, Christophe; Lenggenhager, Bigna; Blanke, Olaf

    2010-03-01

    Artificial stimulation of the peripheral vestibular system has been shown to improve ownership of body parts in neurological patients, suggesting vestibular contributions to bodily self-consciousness. Here, we investigated whether galvanic vestibular stimulation (GVS) interferes with the mechanisms underlying ownership, touch, and the localization of one's own hand in healthy participants by using the "rubber hand illusion" paradigm. Our results show that left anodal GVS increases illusory ownership of the fake hand and illusory location of touch. We propose that these changes are due to vestibular interference with spatial and/or temporal mechanisms of visual-tactile integration leading to an enhancement of visual capture. As only left anodal GVS lead to such changes, and based on neurological data on body part ownership, we suggest that this vestibular interference is mediated by the right temporo-parietal junction and the posterior insula.

  12. Vestibular disorders following different types of head and neck trauma

    PubMed Central

    Kolev, Ognyan I.; Sergeeva, Michaela

    2016-01-01

    Summary This review focuses on the published literature on vestibular disorders following different types of head and neck trauma. Current knowledge of the different causes and underlying mechanisms of vestibular disorders, as well as the sites of organic damage, is presented. Non-organic mechanisms are also surveyed. The frequency of occurrence of vestibular symptoms, and of other accompanying subjective complaints, associated with different types of trauma is presented and related to the specific causes. Hypotheses about the pathogenesis of traumatic vestibular disorders are presented, and the knowledge derived from animal experiments is also discussed. We believe this to be a very important topic, since vestibular complaints in traumatic patients often remain undiagnosed or underestimated in clinical practice. This review article aims to suggest directions for additional research and to provide guidance to both the scientific and clinical practice communities. PMID:27358219

  13. Neural Network Model of Vestibular Nuclei Reaction to Onset of Vestibular Prosthetic Stimulation

    PubMed Central

    DiGiovanna, Jack; Nguyen, T. A. K.; Guinand, Nils; Pérez-Fornos, Angelica; Micera, Silvestro

    2016-01-01

    The vestibular system incorporates multiple sensory pathways to provide crucial information about head and body motion. Damage to the semicircular canals, the peripheral vestibular organs that sense rotational velocities of the head, can severely degrade the ability to perform activities of daily life. Vestibular prosthetics address this problem by using stimulating electrodes that can trigger primary vestibular afferents to modulate their firing rates, thus encoding head movement. These prostheses have been demonstrated chronically in multiple animal models and acutely tested in short-duration trials within the clinic in humans. However, mainly, due to limited opportunities to fully characterize stimulation parameters, there is a lack of understanding of “optimal” stimulation configurations for humans. Here, we model possible adaptive plasticity in the vestibular pathway. Specifically, this model highlights the influence of adaptation of synaptic strengths and offsets in the vestibular nuclei to compensate for the initial activation of the prosthetic. By changing the synaptic strengths, the model is able to replicate the clinical observation that erroneous eye movements are attenuated within 30 minutes without any change to the prosthetic stimulation rate. Although our model was only built to match this time point, we further examined how it affected subsequent pulse rate modulation (PRM) and pulse amplitude modulation (PAM). PAM was more effective than PRM for nearly all stimulation configurations during these acute tests. Two non-intuitive relationships highlighted by our model explain this performance discrepancy. Specifically, the attenuation of synaptic strengths for afferents stimulated during baseline adaptation and the discontinuity between baseline and residual firing rates both disproportionally boost PAM. Comodulation of pulse rate and amplitude has been experimentally shown to induce both excitatory and inhibitory eye movements even at high

  14. Labyrinthectomy and Vestibular Neurectomy for Intractable Vertiginous Symptoms

    PubMed Central

    Alarcón, Alfredo Vega; Hidalgo, Lourdes Olivia Vales; Arévalo, Rodrigo Jácome; Diaz, Marite Palma

    2017-01-01

    Introduction Labyrinthectomy and vestibular neurectomy are considered the surgical procedures with the highest possibility of controlling medically untreatable incapacitating vertigo. Ironically, after 100 years of the introduction of both transmastoid labyrinthectomy and vestibular neurectomy, the choice of which procedure to use rests primarily on the evaluation of the hearing and of the surgical morbidity. Objective To review surgical labyrinthectomy and vestibular neurectomy for the treatment of incapacitating vestibular disorders. Data Sources PubMed, MD consult and Ovid-SP databases. Data Synthesis In this review we describe and compare surgical labyrinthectomy and vestibular neurectomy. A contrast between surgical and chemical labyrinthectomy is also examined. Proper candidate selection, success in vertigo control and complication rates are discussed on the basis of a literature review. Conclusions Vestibular nerve section and labyrinthectomy achieve high and comparable rates of vertigo control. Even though vestibular neurectomy is considered a hearing sparing surgery, since it is an intradural procedure, it carries a greater risk of complications than transmastoid labyrinthectomy. Furthermore, since many patients whose hearing is preserved with vestibular nerve section may ultimately lose that hearing, the long-term value of hearing preservation is not well established. Although the combination of both procedures, in the form of a translabyrinthine vestibular nerve section, is the most certain way to ablate vestibular function for patients with no useful hearing and disabling vertigo, some advocate for transmastoid labyrinthectomy alone, considering that avoiding opening the subarachnoid space minimizes the possible intracranial complications. Chemical labyrinthectomy may be considered a safer alternative, but the risks of hearing loss when hearing preservation is desired are also high. PMID:28382129

  15. The role of the vestibular system in manual target localization

    NASA Technical Reports Server (NTRS)

    Barry, Susan R.; Mueller, S. Alyssa

    1995-01-01

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

  16. Extracranial non-vestibular head and neck schwannomas

    PubMed Central

    Wang, Baoxin; Yuan, Junjie; Chen, Xinwei; Xu, Hongming; Zhou, Yuan; Dong, Pin

    2015-01-01

    Objectives: To retrospectively describe our 10-year experience with extracranial non-vestibular head and neck schwannomas by presenting their clinical features, diagnostic methods, surgical decisions, and treatment outcomes. Methods: This is a retrospective study conducted at the Department of Otolaryngology, Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Shanghai First People’s Hospital, Shanghai, China. The medical records of 46 patients diagnosed with schwannoma in the extracranial head and neck region as confirmed on paraffin-embedded sections from January 2003 to December 2012 were reviewed. Results: All tumors were benign, and 52% presented as asymptomatic palpable solitary masses. Compressive symptoms, which can represent meaningful indicators of the nerve of origin were commonly noted. The most common nerve of origin was the brachial plexus (n=13, 28.3%). Conclusion: While postoperative histopathologic examination is still the gold standard, fine needle aspiration cytology, CT scan, and magnetic resonance imaging may be useful in the diagnosis of schwannomas. As schwannomas are radioresistant, and as, despite their benign nature, can cause severe secondary symptoms, the best treatment of choice is complete excision with preservation of functions. PMID:26593174

  17. Vestibular function in the space environment

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

  18. Experiment M-131 - Human vestibular function.

    NASA Technical Reports Server (NTRS)

    Miller, E. F., II; Graybiel, A.

    1973-01-01

    The purpose of the M-131 experiment is to measure responses in astronauts throughout orbital flight that reflect vestibular function and compare them with measurements made before and after flight. Three subtasks require measurement of (1) susceptibility to motion sickness, (2) thresholds of response to stimulation of the semicircular canals, and (3) space perception, viz, visual and nonvisual localization, using external spacecraft and internal morphological frames of reference. Four astronauts will be available for all measurements in Skylab 2 and 3 and two additional astronauts for only the 'static' measurements during the flights.

  19. Human Vestibular Function - Skylab Experiment M131

    NASA Technical Reports Server (NTRS)

    1972-01-01

    This set of photographs details Skylab's Human Vestibular Function experiment (M131). This experiment was a set of medical studies designed to determine the effect of long-duration space missions on astronauts' coordination abilities. This experiment tested the astronauts susceptibility to motion sickness in the Skylab environment, acquired data fundamental to an understanding of the functions of human gravity reception under prolonged absence of gravity, and tested for changes in the sensitivity of the semicircular canals. Data from this experiment was collected before, during, and after flight. The Marshall Space Flight Center had program management responsibility for the development of Skylab hardware and experiments.

  20. In the presence of others: Self-location, balance control and vestibular processing.

    PubMed

    Lopez, C; Falconer, C J; Deroualle, D; Mast, F W

    2015-11-01

    The degree to which others in our environment influence sensorimotor processing has been a particular focus of cognitive neuroscience for the past two decades. This process of self-other resonance, or shared body representation, has only recently been extended to more global bodily processes such as self-location, self-motion perception, balance and perspective taking. In this review, we outline these previously overlooked areas of research to bridge the distinct field of social neuroscience with global self-perception, vestibular processing and postural control. Firstly, we outline research showing that the presence and movement of others can modulate two fundamental experiences of the self: self-location (the experience of where the self is located in space) and self-motion perception (the experience that oneself has moved or has been moved in space). Secondly, we outline recent research that has shown perturbations in balance control as a result of instability in others in our environment. Conversely to this, we also highlight studies in virtual reality demonstrating the potential benefits of the presence of others in our environment for those undergoing vestibular rehabilitation. Thirdly, we outline studies of first- and third-person perspective taking, which is the ability to have or take a visuo-spatial perspective within and out-with the confines of our own body. These studies demonstrate a contamination of perspective taking processes (i.e. automatic, implicit, third-person perspective taking) in the presence of others. This collection of research highlights the importance of social cues in the more global processing of the self and its accompanying sensory inputs, particularly vestibular signals. Future research will need to better determine the mechanisms of self-other resonance within these processes, including the role of individual differences in the susceptibility to the influence of another.

  1. 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.

  2. Neurogenic Potential of the Vestibular Nuclei and Behavioural Recovery Time Course in the Adult Cat Are Governed by the Nature of the Vestibular Damage

    PubMed Central

    Dutheil, Sophie; Lacour, Michel; Tighilet, Brahim

    2011-01-01

    Functional and reactive neurogenesis and astrogenesis are observed in deafferented vestibular nuclei after unilateral vestibular nerve section in adult cats. The newborn cells survive up to one month and contribute actively to the successful recovery of posturo-locomotor functions. This study investigates whether the nature of vestibular deafferentation has an incidence on the neurogenic potential of the vestibular nuclei, and on the time course of behavioural recovery. Three animal models that mimic different vestibular pathologies were used: unilateral and permanent suppression of vestibular input by unilateral vestibular neurectomy (UVN), or by unilateral labyrinthectomy (UL, the mechanical destruction of peripheral vestibular receptors), or unilateral and reversible blockade of vestibular nerve input using tetrodotoxin (TTX). Neurogenesis and astrogenesis were revealed in the vestibular nuclei using bromodeoxyuridine (BrdU) as a newborn cell marker, while glial fibrillary acidic protein (GFAP) and glutamate decarboxylase 67 (GAD67) were used to identify astrocytes and GABAergic neurons, respectively. Spontaneous nystagmus and posturo-locomotor tests (static and dynamic balance performance) were carried out to quantify the behavioural recovery process. Results showed that the nature of vestibular loss determined the cellular plastic events occurring in the vestibular nuclei and affected the time course of behavioural recovery. Interestingly, the deafferented vestibular nuclei express neurogenic potential after acute and total vestibular loss only (UVN), while non-structural plastic processes are involved when the vestibular deafferentation is less drastic (UL, TTX). This is the first experimental evidence that the vestibular complex in the brainstem can become neurogenic under specific injury. These new data are of interest for understanding the factors favouring the expression of functional neurogenesis in adult mammals in a brain repair perspective, and are of

  3. Stochastic cooling in RHIC

    SciTech Connect

    Brennan,J.M.; Blaskiewicz, M. M.; Severino, F.

    2009-05-04

    After the success of longitudinal stochastic cooling of bunched heavy ion beam in RHIC, transverse stochastic cooling in the vertical plane of Yellow ring was installed and is being commissioned with proton beam. This report presents the status of the effort and gives an estimate, based on simulation, of the RHIC luminosity with stochastic cooling in all planes.

  4. Enlarged vestibular aqueduct in pediatric SNHL

    PubMed Central

    Dewan, Karuna; Wippold, Franz J.; Lieu, Judith E C

    2010-01-01

    Objective Comparison of the Cincinnati criteria (midpoint >0.9 mm or operculum >1.9 mm) to the Valvassori criterion (midpoint ≥ 1.5 mm) for enlarged vestibular aqueduct (EVA) in pediatric cochlear implant patients. Study Design Cohort study Subjects 130 Pediatric cochlear implant recipients. Methods We reviewed temporal bone CT scans to measure the vestibular aqueduct midpoint and opercular width. Results The Cincinnati criteria identified 44% of patients with EVA versus 16% with the Valvassori criterion (P<0.01). Of those with EVA, 45% were unilateral and 55% were bilateral using Cincinnati criteria; 64% were unilateral and 36% bilateral using Valvassori criterion (P<0.01). The Cincinnati criteria diagnosed 70 ears with EVA classified as normal using the Valvassori criterion (P<0.01);59 lacked another medical explanation for their hearing loss. Conclusion The Cincinnati criteria identified a large percentage of pediatric cochlear implant patients with EVA who might otherwise have no known etiology for their deafness. PMID:19328346

  5. Vestibular influence on auditory metrical interpretation.

    PubMed

    Phillips-Silver, Jessica; Trainor, Laurel J

    2008-06-01

    When we move to music we feel the beat, and this feeling can shape the sound we hear. Previous studies have shown that when people listen to a metrically ambiguous rhythm pattern, moving the body on a certain beat--adults, by actively bouncing themselves in synchrony with the experimenter, and babies, by being bounced passively in the experimenter's arms--can bias their auditory metrical representation so that they interpret the pattern in a corresponding metrical form [Phillips-Silver, J., & Trainor, L. J. (2005). Feeling the beat: Movement influences infant rhythm perception. Science, 308, 1430; Phillips-Silver, J., & Trainor, L. J. (2007). Hearing what the body feels: Auditory encoding of rhythmic movement. Cognition, 105, 533-546]. The present studies show that in adults, as well as in infants, metrical encoding of rhythm can be biased by passive motion. Furthermore, because movement of the head alone affected auditory encoding whereas movement of the legs alone did not, we propose that vestibular input may play a key role in the effect of movement on auditory rhythm processing. We discuss possible cortical and subcortical sites for the integration of auditory and vestibular inputs that may underlie the interaction between movement and auditory metrical rhythm perception.

  6. 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.

  7. Auditory perception in vestibular neurectomy subjects.

    PubMed

    Zeng, F G; Martino, K M; Linthicum, F H; Soli, S D

    2000-04-01

    The auditory efferent nerve is a feedback pathway that originates in the brainstem and projects to the inner ear. Although the anatomy and physiology of efferents have been rather thoroughly described, their functional roles in auditory perception are still not clear. Here, we report data in six human subjects who had undergone vestibular neurectomy, during which their efferent nerves were also presumably severed. The surgery had alleviated these subjects' vertigo but also resulted in mild to moderate hearing loss. We designed our experiments with a focus on the possible role of efferents in anti-masking. Consistent with previous studies, we found little effects of vestibular neurectomy on pure-tone detection and discrimination in quiet. However, we noted several new findings in all subjects tested. Efferent section increased loudness sensation (one subject), reduced overshoot effect (five subjects), accentuated 'the midlevel hump' in forward masking (two subjects), and worsened intensity discrimination in noise (four subjects). Poorer speech in noise recognition was also observed in the surgery ear than the non-surgery ear in three out of four subjects tested, but this finding was confounded by hearing loss. The present results suggest an active role of efferents in auditory perception in noise.

  8. Stochastic Gain in Population Dynamics

    NASA Astrophysics Data System (ADS)

    Traulsen, Arne; Röhl, Torsten; Schuster, Heinz Georg

    2004-07-01

    We introduce an extension of the usual replicator dynamics to adaptive learning rates. We show that a population with a dynamic learning rate can gain an increased average payoff in transient phases and can also exploit external noise, leading the system away from the Nash equilibrium, in a resonancelike fashion. The payoff versus noise curve resembles the signal to noise ratio curve in stochastic resonance. Seen in this broad context, we introduce another mechanism that exploits fluctuations in order to improve properties of the system. Such a mechanism could be of particular interest in economic systems.

  9. 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

  10. Nystagmus in Enlarged Vestibular Aqueduct: A Case Series

    PubMed Central

    White, Judith; Krakovitz, Paul

    2015-01-01

    Enlarged vestibular aqueduct (EVA) is one of the commonly identified congenital temporal bone abnormalities associated with sensorineural hearing loss. Hearing loss may be unilateral or bilateral, and typically presents at birth or in early childhood. Vestibular symptoms have been reported in up to 50% of affected individuals, and may be delayed in onset until adulthood. The details of nystagmus in patients with EVA have not been previously reported. The objectives were to describe the clinical history, vestibular test findings and nystagmus seen in a case series of patients with enlarged vestibular aqueduct anomaly. Chart review, included computed tomography temporal bones, infrared nystagmography with positional and positioning testing, caloric testing, rotary chair and vibration testing. Clinical history and nystagmus varied among the five patients in this series. All patients were initially presumed to have benign paroxysmal positional vertigo, but repositioning treatments were not effective, prompting referral, further testing and evaluation. In three patients with longstanding vestibular complaints, positional nystagmus was consistently present. One patient had distinct recurrent severe episodes of positional nystagmus. Nystagmus was unidirectional and horizontal. In one case horizontal nystagmus was consistently reproducible with seated head turn to the affected side, and reached 48 d/s. Nystagmus associated with enlarged vestibular aqueduct is often positional, and can be confused with benign paroxysmal positional vertigo. Unexplained vestibular symptoms in patients with unilateral or bilateral sensorineural hearing loss should prompt diagnostic consideration of EVA. PMID:26557362

  11. 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

  12. 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

  13. 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.

  14. Vestibular inputs to human motion-sensitive visual cortex.

    PubMed

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

    2012-05-01

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

  15. Vestibular compensation: the neuro-otologist's best friend.

    PubMed

    Lacour, Michel; Helmchen, Christoph; Vidal, Pierre-Paul

    2016-04-01

    Why vestibular compensation (VC) after an acute unilateral vestibular loss is the neuro-otologist's best friend is the question at the heart of this paper. The different plasticity mechanisms underlying VC are first reviewed, and the authors present thereafter the dual concept of vestibulo-centric versus distributed learning processes to explain the compensation of deficits resulting from the static versus dynamic vestibular imbalance. The main challenges for the plastic events occurring in the vestibular nuclei (VN) during a post-lesion critical period are neural protection, structural reorganization and rebalance of VN activity on both sides. Data from animal models show that modulation of the ipsilesional VN activity by the contralateral drive substitutes for the normal push-pull mechanism. On the other hand, sensory and behavioural substitutions are the main mechanisms implicated in the recovery of the dynamic functions. These newly elaborated sensorimotor reorganizations are vicarious idiosyncratic strategies implicating the VN and multisensory brain regions. Imaging studies in unilateral vestibular loss patients show the implication of a large neuronal network (VN, commissural pathways, vestibulo-cerebellum, thalamus, temporoparietal cortex, hippocampus, somatosensory and visual cortical areas). Changes in gray matter volume in these multisensory brain regions are structural changes supporting the sensory substitution mechanisms of VC. Finally, the authors summarize the two ways to improve VC in humans (neuropharmacology and vestibular rehabilitation therapy), and they conclude that VC would follow a "top-down" strategy in patients with acute vestibular lesions. Future challenges to understand VC are proposed.

  16. Biomimetic smart sensors for autonomous robotic behavior II: vestibular processing

    NASA Astrophysics Data System (ADS)

    Xue, Shuwan; Deligeorges, Socrates; Soloway, Aaron; Lichtenstein, Lee; Gore, Tyler; Hubbard, Allyn

    2009-05-01

    Limited autonomous behaviors are fast becoming a critical capability in the field of robotics as robotic applications are used in more complicated and interactive environments. As additional sensory capabilities are added to robotic platforms, sensor fusion to enhance and facilitate autonomous behavior becomes increasingly important. Using biology as a model, the equivalent of a vestibular system needs to be created in order to orient the system within its environment and allow multi-modal sensor fusion. In mammals, the vestibular system plays a central role in physiological homeostasis and sensory information integration (Fuller et al, Neuroscience 129 (2004) 461-471). At the level of the Superior Colliculus in the brain, there is multimodal sensory integration across visual, auditory, somatosensory, and vestibular inputs (Wallace et al, J Neurophysiol 80 (1998) 1006-1010), with the vestibular component contributing a strong reference frame gating input. Using a simple model for the deep layers of the Superior Colliculus, an off-the-shelf 3-axis solid state gyroscope and accelerometer was used as the equivalent representation of the vestibular system. The acceleration and rotational measurements are used to determine the relationship between a local reference frame of a robotic platform (an iRobot Packbot®) and the inertial reference frame (the outside world), with the simulated vestibular input tightly coupled with the acoustic and optical inputs. Field testing of the robotic platform using acoustics to cue optical sensors coupled through a biomimetic vestibular model for "slew to cue" gunfire detection have shown great promise.

  17. 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.

  18. Cultured Vestibular Ganglion Neurons Demonstrate Latent HSV1 Reactivation

    PubMed Central

    Roehm, Pamela C.; Camarena, Vladimir; Nayak, Shruti; Gardner, James B.; Wilson, Angus; Mohr, Ian; Chao, Moses V.

    2013-01-01

    Objectives/Hypothesis Vestibular neuritis is a common cause of both acute and chronic vestibular dysfunction. Multiple pathologies have been hypothesized to be the causative agent of vestibular neuritis; however, whether herpes simplex type I (HSV1) reactivation occurs within the vestibular ganglion has not been demonstrated previously by experimental evidence. We developed an in vitro system to study HSV1 infection of vestibular ganglion neurons (VGNs) using a cell culture model system. Study design basic science study. Results Lytic infection of cultured rat VGNs was observed following low viral multiplicity of infection (MOI). Inclusion of acyclovir suppressed lytic replication and allowed latency to be established. Upon removal of acyclovir, latent infection was confirmed with reverse-transcription polymerase chain reaction and by RNA fluorescent in situ hybridization for the latency-associated transcript (LAT). 29% cells in latently infected cultures were LAT positive. The lytic IPC27 transcript was not detected by reverse-transcription polymerase chain reaction (RT-PCR). Reactivation of HSV1 occurred at a high frequency in latently infected cultures following treatment with trichostatin A (TSA), a histone deactylase inhibitor. Conclusions VGNs can be both lytically and latently infected with HSV1. Furthermore, latently infected VGNs can be induced to reactivate using TSA. This demonstrates that reactivation of latent HSV1 infection in the vestibular ganglion can occur in a cell culture model, and suggests that reactivation of HSV1 infection a plausible etiologic mechanism of vestibular neuritis. PMID:21898423

  19. 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.

  20. 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.

  1. 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.

  2. Cross-Modal Calibration of Vestibular Afference for Human Balance

    PubMed Central

    Héroux, Martin E; Law, Tammy C. Y.; Fitzpatrick, Richard C.; Blouin, Jean-Sébastien

    2015-01-01

    To determine how the vestibular sense controls balance, we used instantaneous head angular velocity to drive a galvanic vestibular stimulus so that afference would signal that head movement was faster or slower than actual. In effect, this changed vestibular afferent gain. This increased sway 4-fold when subjects (N = 8) stood without vision. However, after a 240 s conditioning period with stable balance achieved through reliable visual or somatosensory cues, sway returned to normal. An equivalent galvanic stimulus unrelated to sway (not driven by head motion) was equally destabilising but in this situation the conditioning period of stable balance did not reduce sway. Reflex muscle responses evoked by an independent, higher bandwidth vestibular stimulus were initially reduced in amplitude by the galvanic stimulus but returned to normal levels after the conditioning period, contrary to predictions that they would decrease after adaptation to increased sensory gain and increase after adaptation to decreased sensory gain. We conclude that an erroneous vestibular signal of head motion during standing has profound effects on balance control. If it is unrelated to current head motion, the CNS has no immediate mechanism of ignoring the vestibular signal to reduce its influence on destabilising balance. This result is inconsistent with sensory reweighting based on disturbances. The increase in sway with increased sensory gain is also inconsistent with a simple feedback model of vestibular reflex action. Thus, we propose that recalibration of a forward sensory model best explains the reinterpretation of an altered reafferent signal of head motion during stable balance. PMID:25894558

  3. Betahistine treatment in managing vertigo and improving vestibular compensation: clarification.

    PubMed

    Lacour, Michel

    2013-01-01

    Betahistine dihydrochloride (betahistine) is currently used in the management of vertigo and vestibular pathologies with different aetiologies. The main goal of this review is to clarify the mechanisms of action of this drug, responsible for the symptomatic relief of vertigo and the improvement of vestibular compensation. The review starts with a brief summary recalling the role of histamine as a neuromodulator/neurotransmitter in the control of the vestibular functions, and the role of the histaminergic system in vestibular compensation. Then are presented data recorded in animal models demonstrating that betahistine efficacy can be explained by mechanisms targeting the histamine receptors (HRs) at three different levels: the vascular tree, with an increase of cochlear and vestibular blood flow involving the H1R; the central nervous system, with an increase of histamine turnover implicating the H3R, and the peripheral labyrinth, with a decrease of vestibular input implying the H3R/H4R. Clinical data from vestibular loss patients show the impact of betahistine treatment for the long-term control of vertigo, improvement of balance and quality of life that can be explained by these mechanisms of action. However, two conditions, at least, are required for reaching the betahistine therapeutic effect: the dose and the duration of treatment. Experimental and clinical data supporting these requirements are exposed in the last part of this review.

  4. Medical and Nonstroke Neurologic Causes of Acute, Continuous Vestibular Symptoms.

    PubMed

    Edlow, Jonathan A; Newman-Toker, David E

    2015-08-01

    Most patients with the acute vestibular syndrome (AVS) have vestibular neuritis or stroke or, in the setting of trauma, a posttraumatic vestibular cause. Some medical and nonstroke causes of the AVS must also be considered. Multiple sclerosis is the most common diagnosis in this group. Other less common causes include cerebellar masses, inflammation and infection, mal de debarquement, various toxins, Wernicke disease, celiac-related dizziness, and bilateral vestibulopathy. Finally, there may be unmasking of prior posterior circulation events by various physiologic alterations such as alterations of temperature, blood pressure, electrolytes, or various medications, especially sedating agents.

  5. The Development of the Vestibular Apparatus Under Conditions of Weightlessness

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  6. Overview of the International Classification of Vestibular Disorders.

    PubMed

    Bisdorff, Alexandre R; Staab, Jeffrey P; Newman-Toker, David E

    2015-08-01

    Classifications and definitions are essential to facilitate communication; promote accurate diagnostic criteria; develop, test, and use effective therapies; and specify knowledge gaps. This article describes the development of the International Classification of Vestibular Disorders (ICVD) initiative. It describes its history, scope, and goals. The Bárány Society has played a central role in organizing the ICVD by establishing internal development processes and outreach to other scientific societies. The ICVD is organized in four layers. The current focus is on disorders with a high epidemiologic importance, such as Menière disease, benign paroxysmal positional vertigo, vestibular migraine, and behavioral aspects of vestibular disorders.

  7. Stochastic differential equations

    SciTech Connect

    Sobczyk, K. )

    1990-01-01

    This book provides a unified treatment of both regular (or random) and Ito stochastic differential equations. It focuses on solution methods, including some developed only recently. Applications are discussed, in particular an insight is given into both the mathematical structure, and the most efficient solution methods (analytical as well as numerical). Starting from basic notions and results of the theory of stochastic processes and stochastic calculus (including Ito's stochastic integral), many principal mathematical problems and results related to stochastic differential equations are expounded here for the first time. Applications treated include those relating to road vehicles, earthquake excitations and offshore structures.

  8. Vestibular contributions to a right-hemisphere network for bodily awareness: combining galvanic vestibular stimulation and the "Rubber Hand Illusion".

    PubMed

    Ferrè, Elisa Raffaella; Berlot, Eva; Haggard, Patrick

    2015-03-01

    An altered sense of one's own body is a common consequence of vestibular damage, and also of damage to vestibular networks in the right hemisphere. However, few experimental studies have investigated whether vestibular signals contribute to bodily awareness. We addressed this issue by combining an established experimental model of bodily awareness (Rubber Hand Illusion -RHI) with galvanic vestibular stimulation (GVS) in healthy participants. Brief left anodal and right cathodal GVS (which predominantly activates vestibular networks in the right hemisphere), or right anodal and left cathodal GVS, or sham stimulation were delivered at random, while participants experienced either synchronous or asynchronous visuo-tactile stimulation of a rubber hand and their own hand. The drift in the perceived position of the participant's hand towards the rubber hand was used as a proxy measure of the resulting multisensory illusion of body ownership. GVS induced strong polarity-dependent effects on this measure of RHI: left anodal and right cathodal GVS produced significantly lower proprioceptive drift than right anodal and left cathodal GVS. We suggest that vestibular inputs influence the multisensory weighting functions that underlie bodily awareness: the right hemisphere vestibular projections activated by the left anodal and right cathodal GVS increased the weight of intrinsic proprioceptive signals about hand position, and decreased the weight of visual information responsible for visual capture during the RHI.

  9. Stochastic symmetries of Wick type stochastic ordinary differential equations

    NASA Astrophysics Data System (ADS)

    Ünal, Gazanfer

    2015-04-01

    We consider Wick type stochastic ordinary differential equations with Gaussian white noise. We define the stochastic symmetry transformations and Lie equations in Kondratiev space (S)-1N. We derive the determining system of Wick type stochastic partial differential equations with Gaussian white noise. Stochastic symmetries for stochastic Bernoulli, Riccati and general stochastic linear equation in (S)-1N are obtained. A stochastic version of canonical variables is also introduced.

  10. Stochastic Resonance in a Bistable Squid Loop

    DTIC Science & Technology

    1993-08-01

    as a possible explanation for the observed periodicities in the recurrences of the Earth’s Ice Ages. The first publication of a modern theory led to... fields . Using a modern, miniature, thin film SQUID, we hope this demonstration will stimulate further research and development of SR in applied

  11. Role of the flocculus in mediating vestibular nucleus neuron plasticity during vestibular compensation in the rat

    PubMed Central

    Johnston, Alex R; Seckl, Jonathan R; Dutia, Mayank B

    2002-01-01

    We investigated the role of the cerebellar flocculus in mediating the adaptive changes that occur in the intrinsic properties of brainstem medial vestibular nucleus (MVN) neurons during vestibular compensation. Ipsi-lesional, but not contra-lesional, flocculectomy prevented the compensatory increase in intrinsic excitability (CIE) that normally occurs in the de-afferented MVN neurons within 4 h after unilateral labyrinthectomy (UL). Flocculectomy did not, however, prevent the down-regulation of efficacy of GABA receptors that also occurs in these neurons after UL, indicating that these responses of the MVN neurons to deafferentation are discrete, parallel processes. CIE was also abolished by intra-floccular microinjection of the metabotropic glutamate receptor (mGluR) antagonist AIDA, and the protein kinase C inhibitor bisindolymaleimide I (BIS-I). The serene-threonine kinase inhibitor H-7 had no effect when microinjected at the time of de-afferentation, but abolished CIE if microinjected 2 h later. These cellular effects are in line with the recently reported retardatory effects of BIS-I and H-7 on behavioural recovery after UL. They demonstrate that the increase in intrinsic excitability in MVN neurons during vestibular compensation is cerebellum dependent, and requires mGluR activation and protein phosphorylation in cerebellar cortex. Furthermore, microinjection of the glucocorticoid receptor (GR) antagonist RU38486 into the ipsi-lesional flocculus also abolished CIE in MVN neurons. Thus an important site for glucocorticoids in facilitating vestibular compensation is within the cerebellar cortex. These observations ascribe functional significance to the high levels of GR and 11-β-HSD Type 1 expression in cerebellum. PMID:12482895

  12. Vestibular Function Tests for Vestibular Migraine: Clinical Implication of Video Head Impulse and Caloric Tests

    PubMed Central

    Kang, Woo Seok; Lee, Sang Hun; Yang, Chan Joo; Ahn, Joong Ho; Chung, Jong Woo; Park, Hong Ju

    2016-01-01

    Vestibular migraine (VM) is one of the most common causes of episodic vertigo. We reviewed the results of multiple vestibular function tests in a cohort of VM patients who were diagnosed with VM according to the diagnostic criteria of the Barany Society and the International Headache Society and assessed the efficacy of each for predicting the prognosis in VM patients. A retrospective chart analysis was performed on 81 VM patients at a tertiary care center from June 2014 to July 2015. Patients were assessed by the video head impulse test (vHIT), caloric test, vestibular-evoked myogenic potentials (VEMPs), and sensory organization test (SOT) at the initial visit and then evaluated for symptomatic improvement after 6 months. Complete response (CR) was defined as no need for continued medication, partial response (PR) as improved symptoms but need for continued medication, and no response (NR) as no symptomatic improvement and requiring increased dosage or change in medications. At the initial evaluation, 9 of 81 patients (11%) exhibited abnormal vHIT results, 14 of 73 (19%) exhibited abnormal caloric test results, 25 of 65 (38%) exhibited abnormal SOT results, 8 of 75 (11%) exhibited abnormal cervical VEMP results, and 20 of 75 (27%) exhibited abnormal ocular VEMP results. Six months later, 63 of 81 patients (78%) no longer required medication (CR), while 18 (22%) still required medication, including 7 PR and 11 NR patients. Abnormal vHIT gain and abnormal caloric results were significantly related to the necessity for continued medication at 6-month follow-up (OR = 5.67 and 4.36, respectively). Abnormal vHIT and caloric test results revealed semicircular canal dysfunction in VM patients and predicted prolonged preventive medication requirement. These results suggest that peripheral vestibular abnormalities are closely related to the development of vertigo in VM patients. PMID:27746761

  13. Vestibular Function Tests for Vestibular Migraine: Clinical Implication of Video Head Impulse and Caloric Tests.

    PubMed

    Kang, Woo Seok; Lee, Sang Hun; Yang, Chan Joo; Ahn, Joong Ho; Chung, Jong Woo; Park, Hong Ju

    2016-01-01

    Vestibular migraine (VM) is one of the most common causes of episodic vertigo. We reviewed the results of multiple vestibular function tests in a cohort of VM patients who were diagnosed with VM according to the diagnostic criteria of the Barany Society and the International Headache Society and assessed the efficacy of each for predicting the prognosis in VM patients. A retrospective chart analysis was performed on 81 VM patients at a tertiary care center from June 2014 to July 2015. Patients were assessed by the video head impulse test (vHIT), caloric test, vestibular-evoked myogenic potentials (VEMPs), and sensory organization test (SOT) at the initial visit and then evaluated for symptomatic improvement after 6 months. Complete response (CR) was defined as no need for continued medication, partial response (PR) as improved symptoms but need for continued medication, and no response (NR) as no symptomatic improvement and requiring increased dosage or change in medications. At the initial evaluation, 9 of 81 patients (11%) exhibited abnormal vHIT results, 14 of 73 (19%) exhibited abnormal caloric test results, 25 of 65 (38%) exhibited abnormal SOT results, 8 of 75 (11%) exhibited abnormal cervical VEMP results, and 20 of 75 (27%) exhibited abnormal ocular VEMP results. Six months later, 63 of 81 patients (78%) no longer required medication (CR), while 18 (22%) still required medication, including 7 PR and 11 NR patients. Abnormal vHIT gain and abnormal caloric results were significantly related to the necessity for continued medication at 6-month follow-up (OR = 5.67 and 4.36, respectively). Abnormal vHIT and caloric test results revealed semicircular canal dysfunction in VM patients and predicted prolonged preventive medication requirement. These results suggest that peripheral vestibular abnormalities are closely related to the development of vertigo in VM patients.

  14. Optokinetic and Vestibular Responsiveness in the Macaque Rostral Vestibular and Fastigial Nuclei

    PubMed Central

    Bryan, Ayanna S.; Angelaki, Dora E.

    2009-01-01

    We recorded from rostral vestibular (VN) and rostral fastigial nuclei (FN) neurons that did not respond to eye movements during three-dimensional (3D) vestibular and optokinetic stimulation (OKS). The majority of neurons in both areas (76 and 69% in VN and FN, respectively) responded during both rotational and translational motion. Preferred directions scattered throughout 3D space for translation but showed some preference for pitch/roll over yaw for rotation. VN/FN neurons were also tested during OKS while monkeys suppressed their optokinetic nystagmus by fixating a head-fixed target. Only a handful of cells (VN: 17%, FN: 6%) modulated during 0.5-Hz OKS suppression, but the number of responsive cells increased (VN: 40%, FN: 48%) during 0.02-Hz OKS. Preferred directions for rotation and OKS were not matched on individual neurons, and OKS gains were smaller than the respective gains during rotation. These results were generally similar for VN and FN neurons. We conclude that optokinetic-vestibular convergence might not be as prevalent as earlier studies have suggested. PMID:19073813

  15. Balancing awareness: Vestibular signals modulate visual consciousness in the absence of awareness.

    PubMed

    Salomon, Roy; Kaliuzhna, Mariia; Herbelin, Bruno; Blanke, Olaf

    2015-11-01

    The processing of visual and vestibular information is crucial for perceiving self-motion. Visual cues, such as optic flow, have been shown to induce and alter vestibular percepts, yet the role of vestibular information in shaping visual awareness remains unclear. Here we investigated if vestibular signals influence the access to awareness of invisible visual signals. Using natural vestibular stimulation (passive yaw rotations) on a vestibular self-motion platform, and optic flow masked through continuous flash suppression (CFS) we tested if congruent visual-vestibular information would break interocular suppression more rapidly than incongruent information. We found that when the unseen optic flow was congruent with the vestibular signals perceptual suppression as quantified with the CFS paradigm was broken more rapidly than when it was incongruent. We argue that vestibular signals impact the formation of visual awareness through enhanced access to awareness for congruent multisensory stimulation.

  16. Mutations of ESPN cause autosomal recessive deafness and vestibular dysfunction

    PubMed Central

    Naz, S; Griffith, A; Riazuddin, S; Hampton, L; Battey, J; Khan, S; Riazuddin, S; Wilcox, E; Friedman, T

    2004-01-01

    We mapped a human deafness locus DFNB36 to chromosome 1p36.3 in two consanguineous families segregating recessively inherited deafness and vestibular areflexia. This phenotype co-segregates with either of two frameshift mutations, 1988delAGAG and 2469delGTCA, in ESPN, which encodes a calcium-insensitive actin-bundling protein called espin. A recessive mutation of ESPN is known to cause hearing loss and vestibular dysfunction in the jerker mouse. Our results establish espin as an essential protein for hearing and vestibular function in humans. The abnormal vestibular phenotype associated with ESPN mutations will be a useful clinical marker for refining the differential diagnosis of non-syndromic deafness. PMID:15286153

  17. Certain aspects of the vestibular problem in space medicine

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Vestibulovegetative disorders on manned space flights are discussed. A study relating to the vestibular stimuli in respiration, diaphoresis cardiac rhythm and a broad complex of hemodynamic indices was conducted. Certain tests for astronaut candidates are discussed.

  18. International guidelines for education in vestibular rehabilitation therapy.

    PubMed

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

    2011-01-01

    The Barany Society Ad Hoc Committee on Vestibular Rehabilitation Therapy has developed guidelines for developing educational programs for continuing education. These guidelines may be useful to individual therapists who seek to learn about vestibular rehabilitation or who seek to improve their knowledge bases. These guidelines may also be useful to professional organizations or therapists who provide continuing education in vestibular rehabilitation. We recommend a thorough background in basic vestibular science as well as an understating of current objective diagnostic testing and diagnoses, understanding of common tests used by therapists to assess postural control, vertigo and ability to perform activities of daily living. We recommend that therapists be familiar with the evidence supporting efficacy of available treatments as well as with limitations in the current research.

  19. Surgical access to separate branches of the cat vestibular nerve

    NASA Technical Reports Server (NTRS)

    Radkevich, L. A.; Ayzikov, G. S.

    1981-01-01

    A posteroventral approach for access to separate branches of the cat vestibular nerve is presented which permits simultaneous surgical access to the ampullary and otolithic nerves. Surgical procedures are discussed.

  20. Vestibular feedback maintains reaching accuracy during body movement

    PubMed Central

    Reynolds, Raymond F.

    2016-01-01

    Key points Reaching movements can be perturbed by vestibular input, but the function of this response is unclear.Here, we applied galvanic vestibular stimulation concurrently with real body movement while subjects maintained arm position either fixed in space or fixed with respect to their body.During the fixed‐in‐space conditions, galvanic vestibular stimulation caused large changes in arm trajectory consistent with a compensatory response to maintain upper‐limb accuracy in the face of body movement.Galvanic vestibular stimulation responses were absent during the body‐fixed task, demonstrating task dependency in vestibular control of the upper limb.The results suggest that the function of vestibular‐evoked arm movements is to maintain the accuracy of the upper limb during unpredictable body movement, but only when reaching in an earth‐fixed reference frame. Abstract When using our arms to interact with the world, unintended body motion can introduce movement error. A mechanism that could detect and compensate for such motion would be beneficial. Observations of arm movements evoked by vestibular stimulation provide some support for this mechanism. However, the physiological function underlying these artificially evoked movements is unclear from previous research. For such a mechanism to be functional, it should operate only when the arm is being controlled in an earth‐fixed rather than a body‐fixed reference frame. In the latter case, compensation would be unnecessary and even deleterious. To test this hypothesis, subjects were gently rotated in a chair while being asked to maintain their outstretched arm pointing towards either earth‐fixed or body‐fixed memorized targets. Galvanic vestibular stimulation was applied concurrently during rotation to isolate the influence of vestibular input, uncontaminated by inertial factors. During the earth‐fixed task, galvanic vestibular stimulation produced large polarity‐dependent corrections in arm

  1. Caloric vestibular stimulation in aphasic syndrome

    PubMed Central

    Wilkinson, David; Morris, Rachael; Milberg, William; Sakel, Mohamed

    2013-01-01

    Caloric vestibular stimulation (CVS) is commonly used to diagnose brainstem disorder but its therapeutic application is much less established. Based on the finding that CVS increases blood flow to brain structures associated with language and communication, we assessed whether the procedure has potential to relieve symptoms of post-stroke aphasia. Three participants, each presenting with chronic, unilateral lesions to the left hemisphere, were administered daily CVS for four consecutive weeks. Relative to their pre-treatment baseline scores, two of the three participants showed significant improvement on both picture and responsive naming at immediate and 1-week follow-up. One of these participants also showed improved sentence repetition, and another showed improved auditory word discrimination. No adverse reactions were reported. These data provide the first, albeit tentative, evidence that CVS may relieve expressive and receptive symptoms of aphasia. A larger, sham-controlled study is now needed to further assess efficacy. PMID:24391559

  2. The European vestibular experiments in spacelab-1

    NASA Astrophysics Data System (ADS)

    Kass, J.; von Baumgarten, R.; Vogel, H.; Wetzig, J.; Benson, A.; Berthoz, A.; Vieville, Th.; Brandt, Th.; Probst, Th.; Brand, U.; Bruzek, W.; Dichgans, J.; Scherer, H.

    A series of experiments /1/ were performed in the Spacelab-1 mission on November/December, 1983, pre-, in-, and postflight. These experiments covered various aspects of the functions of the vestibular system, the inflight tests comprising threshold measurements for linear movements in three orthogonal axes, optokinetic stimulation, vestibulo-ocular reflexes under linear and angular accelerations, caloric stimulation with and without linear accelerations; pre- and postflight tests repeated the inflight protocol with the addition of subjective vertical and eye counter-rotation measurements using a tilt table. One of the most surprising and significant results was the caloric test: strong caloric nystagmus on the two subjects tested was recorded inflight; this was contrary to what was expected from Barany's convection hypothesis for caloric nystagmus.

  3. Vestibular ataxia and its measurement in man

    NASA Technical Reports Server (NTRS)

    Fregly, A. R.

    1974-01-01

    Methods involved in and results obtained with a new comprehensive ataxia test battery are described, and definitions of spontaneous and induced vestibular ataxia in man are given in terms of these findings. In addition, the topic of alcohol-induced ataxia in relation to labyrinth function is investigated. Items in the test battery comprise a sharpened Romberg test, in which the subject stands on the floor with eyes closed and arms folded against his chest, feet heel-to-toe, for 60 seconds; an eyes-open walking test; an eyes-open standing test; an eyes-closed standing test; an eyes-closed on-leg standing test; an eyes-closed walk a line test; an eyes-closed heel-to-toe walking test; and supplementary ataxia tests such as the classical Romberg test.

  4. Effect of gravity on vestibular neural development

    NASA Technical Reports Server (NTRS)

    Ross, M. D.; Tomko, D. L.

    1998-01-01

    The timing, molecular basis, and morphophysiological and behavioral consequences of the interaction between external environment and the internal genetic pool that shapes the nervous system over a lifetime remain important questions in basic neuroscientific research. Space station offers the opportunity to study this interaction over several life cycles in a variety of organisms. This short review considers past work in altered gravity, particularly on the vestibular system, as the basis for proposing future research on space station, and discusses the equipment necessary to achieve goals. It is stressed that, in keeping with the international investment being made in this research endeavor, both the questions asked and the technologies to be developed should be bold. Advantage must be taken of this unique research environment to expand the frontiers of neuroscience. Copyright 1998 Published by Elsevier Science B.V.

  5. Early and Phasic Cortical Metabolic Changes in Vestibular Neuritis Onset

    PubMed Central

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

    2013-01-01

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

  6. Early and phasic cortical metabolic changes in vestibular neuritis onset.

    PubMed

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

    2013-01-01

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

  7. Timing of neuron development in the rodent vestibular system

    NASA Technical Reports Server (NTRS)

    Keefe, J. R.

    1982-01-01

    The timing of cell generation (onset and duration) in the developing rat vestibular and proprioceptive systems is investigated. The results clearly indicate a defined time-span for generation of all neurons in the central nervous system nuclei studied. This cytogenetic period in both vestibular and proprioceptive sensory nuclei is determined to occur during and immediately after placentation, a potentially critical period for spaceflight exposure due to alterations in maternal physiology.

  8. Effects of Tactile and Audio Cues on Reducing Vestibular Illusions

    DTIC Science & Technology

    2006-09-01

    3-D audio, tactile belt) to overcome a vestibular illusion in a rotating Barany Chair was investigated. Seated subjects were rotated about their...Conclusions 14 6.0 Recommendations 15 7.0 References 17 List of Figures 1. Neuro Kinetics Inc Barany (Rotary) Chair System 5 2. Schematic of chair...vestibular illusion in a rotating Barany Chair was investigated. Seated subjects were rotated about their spinal axis (Z axis) from a standing stop to a

  9. Vestibular and oculomotor influences on visual dependency

    PubMed Central

    Da Silva Melo, Mariane; Siddiqui, Aazim A.; Arshad, Qadeer; Patel, Mitesh

    2016-01-01

    The degree to which a person relies on visual stimuli for spatial orientation is termed visual dependency (VD). VD is considered a perceptual trait or cognitive style influenced by psychological factors and mediated by central reweighting of the sensory inputs involved in spatial orientation. VD is often measured with the rod-and-disk test, in which participants align a central rod to the subjective visual vertical (SVV) in the presence of a background that is either stationary or rotating around the line of sight—dynamic SVV. Although this task has been employed to assess VD in health and vestibular disease, what effect torsional nystagmic eye movements may have on individual performance is unknown. Using caloric ear irrigation, 3D video-oculography, and the rod-and-disk test, we show that caloric torsional nystagmus modulates measures of VD and demonstrate that increases in tilt after irrigation are positively correlated with changes in ocular torsional eye movements. When the direction of the slow phase of the torsional eye movement induced by the caloric is congruent with that induced by the rotating visual stimulus, there is a significant increase in tilt. When these two torsional components are in opposition, there is a decrease. These findings show that measures of VD can be influenced by oculomotor responses induced by caloric stimulation. The findings are of significance for clinical studies, as they indicate that VD, which often increases in vestibular disorders, is modulated not only by changes in cognitive style but also by eye movements, in particular nystagmus. PMID:27358321

  10. [Vestibularly displaced flap with bone augmentation].

    PubMed

    Bakalian, V L

    2009-01-01

    The aim of this study is to achieve esthetic gingival contours with the help of less traumatic mucogingival surgeries. 9 Patients were operated with horizontal deficiencies in 9 edentulous sites, planned to be restored with fixed partial dentures. In all cases there was lack of keratinized tissues. Temporary bridges were fabricated to all patients. Before surgery the bridges were removed and the abutment teeth were additionally cleaned with ultrasonic device. A horizontal incision was made from lingual (palatal) side between the abutment teeth, which was connected with two vertical releasing incisions to the mucogingival junction from the vestibular side. The horizontal incision was made on a distance 6-10 mm from the crest of the alveolar ridge. A partial thickness flap in the beginning 3-5 mm, then a full thickness flap up to the mucogingival junction, then a partial thickness flap was made. The flap was mobilized and displaced vestibularly. In the apical part the cortical bone was perforated, graft material was put and the flap was sutured. In all 9 cases the horizontal defect was partially or fully eliminated. The width of the keratinized tissues was also augmented in all cases. The postoperative healing was without complications, discomfort and painless. The donor sites also healed without complications. The application of Solcoseryl Dental Adhesive Paste 3 times a day for 7-10 days helped for painless healing of the donor site. The offered method of soft tissue and bone augmentation is effective in the treatment of horizontal defects of edentulous alveolar ridges of not big sizes. It makes possible to achieve esthetic results without traumatizing an additional donor-site.

  11. Vestibular adaptation to space in monkeys

    NASA Technical Reports Server (NTRS)

    Dai, M.; Raphan, T.; Kozlovskaya, I.; Cohen, B.

    1998-01-01

    Otolith-induced eye movements of rhesus monkeys were studied before and after the 1989 COSMOS 2044 and the 1992 to 1993 COSMOS 2229 flights. Two animals flew in each mission for approximately 2 weeks. After flight, spatial orientation of the angular vestibulo-ocular reflex was altered. In one animal the time constant of postrotatory nystagmus, which had been shortened by head tilts with regard to gravity before flight, was unaffected by the same head tilts after flight. In another animal, eye velocity, which tended to align with a gravitational axis before flight, moved toward a body axis after flight. This shift of orientation disappeared by 7 days after landing. After flight, the magnitude of compensatory ocular counter-rolling was reduced by about 70% in both dynamic and static tilts. Modulation in vergence in response to naso-occipital linear acceleration during off-vertical axis rotation was reduced by more than 50%. These changes persisted for 11 days after recovery. An up and down asymmetry of vertical nystagmus was diminished for 7 days. Gains of the semicircular canal-induced horizontal and vertical angular vestibulo-ocular reflexes were unaffected in both flights, but the gain of the roll angular vestibulo-ocular reflex was decreased. These data indicate that there are short- and long-term changes in otolith-induced eye movements after adaptation to microgravity. These experiments also demonstrate the unique value of the monkey as a model for studying effects of vestibular adaptation in space. Eye movements can be measured in three dimensions in response to controlled vestibular and visual stimulation, and the results are directly applicable to human beings. Studies in monkeys to determine how otolith afferent input and central processing is altered by adaptation to microgravity should be an essential component of future space-related research.

  12. Vestibular contributions to high-level sensorimotor functions.

    PubMed

    Medendorp, W Pieter; Selen, Luc J P

    2017-02-02

    The vestibular system, which detects motion and orientation of the head in space, is known to be important in controlling gaze to stabilize vision, to ensure postural stability and to provide our sense of self-motion. While the brain's computations underlying these functions are extensively studied, the role of the vestibular system in higher level sensorimotor functions is less clear. This review covers new research on the vestibular influence on perceptual judgments, motor decisions, and the ability to learn multiple motor actions. Guided by concepts such as optimization, inference, estimation and control, we focus on how the brain determines causal relationships between memorized and visual representations in the updating of visual space, and how vestibular, visual and efferent motor information are integrated in the estimation of body motion. We also discuss evidence that these computations involve multiple coordinate representations, some of which can be probed in parietal cortex using neuronal oscillations derived from EEG. In addition, we describe work on decision making during self-motion, showing a clear modulation of bottom-up acceleration signals on decisions in the saccadic system. Finally, we consider the importance of vestibular signals as contextual cues in motor learning and recall. Taken together, these results emphasize the impact of vestibular information on high-level sensorimotor functions, and identify future directions for theoretical, behavioral, and neurophysiological investigations.

  13. 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.

  14. Vestibular activity and cognitive development in children: perspectives

    PubMed Central

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

    2013-01-01

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

  15. Neuroticism modulates brain visuo-vestibular and anxiety systems during a virtual rollercoaster task.

    PubMed

    Riccelli, Roberta; Indovina, Iole; Staab, Jeffrey P; Nigro, Salvatore; Augimeri, Antonio; Lacquaniti, Francesco; Passamonti, Luca

    2017-02-01

    Different lines of research suggest that anxiety-related personality traits may influence the visual and vestibular control of balance, although the brain mechanisms underlying this effect remain unclear. To our knowledge, this is the first functional magnetic resonance imaging (fMRI) study that investigates how individual differences in neuroticism and introversion, two key personality traits linked to anxiety, modulate brain regional responses and functional connectivity patterns during a fMRI task simulating self-motion. Twenty-four healthy individuals with variable levels of neuroticism and introversion underwent fMRI while performing a virtual reality rollercoaster task that included two main types of trials: (1) trials simulating downward or upward self-motion (vertical motion), and (2) trials simulating self-motion in horizontal planes (horizontal motion). Regional brain activity and functional connectivity patterns when comparing vertical versus horizontal motion trials were correlated with personality traits of the Five Factor Model (i.e., neuroticism, extraversion-introversion, openness, agreeableness, and conscientiousness). When comparing vertical to horizontal motion trials, we found a positive correlation between neuroticism scores and regional activity in the left parieto-insular vestibular cortex (PIVC). For the same contrast, increased functional connectivity between the left PIVC and right amygdala was also detected as a function of higher neuroticism scores. Together, these findings provide new evidence that individual differences in personality traits linked to anxiety are significantly associated with changes in the activity and functional connectivity patterns within visuo-vestibular and anxiety-related systems during simulated vertical self-motion. Hum Brain Mapp 38:715-726, 2017. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  16. Current treatment of nasal vestibular stenosis with CO2-laser surgery: prolonged vestibular stenting versus intraoperative mitomycin application. A case series of 3 patients.

    PubMed

    van Schijndel, Olaf; van Heerbeek, Niels; Ingels, Koen J A O

    2014-12-01

    These case studies describe three cases of unilateral nasal vestibular stenoses caused by chemical cauterization. Each case was treated with CO2-laser surgery together with intraoperative topic application of mitomycin or prolonged vestibular stenting for prevention of restenosis. Two patients received intraoperative mitomycin application and one patient received prolonged vestibular stenting. Results were documented using high-resolution photographs. The follow up period ranged from 1 year and 3 months to 4 years and 9 months. All patients improved after CO2-laser surgery. No complications were reported. We consider CO2-laser surgery for relief of nasal vestibular stenosis as a feasible surgical technique for relieve of nasal vestibular stenosis. Prolonged vestibular stenting seems to be an important factor for the prevention of restenosis in which the value of intraoperative mitomycin application without prolonged vestibular stenting remains uncertain.

  17. 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

  18. Role of vestibular information in initiation of rapid postural responses.

    PubMed

    Runge, C F; Shupert, C L; Horak, F B; Zajac, F E

    1998-10-01

    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

  19. Restoring Visual Acuity in Dynamic Conditions with a Vestibular Implant

    PubMed Central

    Guinand, Nils; Van de Berg, Raymond; Cavuscens, Samuel; Stokroos, Robert; Ranieri, Maurizio; Pelizzone, Marco; Kingma, Herman; Guyot, Jean-Philippe; Pérez Fornos, Angélica

    2016-01-01

    Vestibular implants are devices designed to rehabilitate patients with a bilateral vestibular loss (BVL). These patients lack a properly functioning vestibulo-ocular reflex (VOR), which impairs gaze stabilization abilities and results in an abnormal loss of visual acuity (VA) in dynamic situations (i.e., severely limiting the patient's ability to read signs or recognize faces while walking). We previously demonstrated that the VOR can be artificially restored in a group of BVL patients fitted with a prototype vestibular implant. This study was designed to investigate whether these promising results could be translated to a close-to-reality task, significantly improving VA abilities while walking. Six BVL patients previously implanted with a vestibular implant prototype participated in the experiments. VA was determined using Sloan letters displayed on a computer screen, in four conditions: (1) with the patient standing still without moving (static), (2) while the patient was walking on a treadmill at constant speed with the vestibular implant prototype turned off (systemOFF), (3) while the patient was walking on a treadmill at constant speed with the vestibular implant prototype turned on providing coherent motion information (systemONmotion), and (4) a “placebo” condition where the patient was walking on a treadmill at constant speed with the vestibular implant prototype turned on providing reversed motion information (systemONsham). The analysis (one-way repeated measures analysis of variance) revealed a statistically significant effect of the test condition [F(3, 12) = 30.5, p < 0.001]. Significant decreases in VA were observed with the systemOFF condition when compared to the static condition (Tukey post-hoc p < 0.001). When the vestibular implant was turned on, delivering pertinent motion information (systemONmotion) the VA improved to close to normal values. The improvement disappeared in the placebo condition (systemONsham) and VA-values also dropped

  20. Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) - a case report and review of literature.

    PubMed

    Figura, Monika; Gaweł, Małgorzata; Kolasa, Anna; Janik, Piotr

    2014-01-01

    CANVAS (cerebellar ataxia with neuropathy and vestibular areflexia syndrome) is a rare neurological syndrome of unknown etiology. The main clinical features include bilateral vestibulopathy, cerebellar ataxia and sensory neuropathy. An abnormal visually enhanced vestibulo-ocular reflex is the hallmark of the disease. We present a case of 58-year-old male patient who has demonstrated gait disturbance, imbalance and paresthesia of feet for 2 years. On examination ataxia of gait, diminished knee and ankle reflexes, absence of plantar reflexes, fasciculations of thigh muscles, gaze-evoked downbeat nystagmus and abnormal visually enhanced vestibulo-ocular reflex were found. Brain magnetic resonance imaging revealed cerebellar atrophy. Vestibular function testing showed severely reduced horizontal nystagmus in response to bithermal caloric stimulation. Nerve conduction study revealed loss of upper and lower limb sensory nerve action potentials. The course of illness was progressive with ataxic gait and unsteadiness as the most disabling symptoms. We report 4-year follow-up of the patient since the beginning of the disease.

  1. Ocular vestibular evoked myogenic potential frequency tuning in certain Menière's disease.

    PubMed

    Jerin, Claudia; Berman, Albert; Krause, Eike; Ertl-Wagner, Birgit; Gürkov, Robert

    2014-04-01

    Ocular vestibular evoked myogenic potentials (oVEMP) represent extraocular muscle activity in response to vestibular stimulation. To specify the value of oVEMP in the diagnostics of Menière's disease, the amplitude ratio between 500 and 1000 Hz stimuli was investigated. Thirty-nine patients with certain Menière's disease, i.e. definite Menière's disease with visualization of endolymphatic hydrops by magnetic resonance imaging and 19 age-matched healthy controls were enrolled in this study. oVEMP were recorded using 500 and 1000 Hz air-conducted tone bursts. For Menière's ears, the 500/1000 Hz amplitude ratio (mean ratio = 1.20) was significantly smaller when compared to unaffected ears of Menière's patients (mean ratio = 1.80; p = 0.008) or healthy controls (mean ratio = 1.81; p = 0.011). The amplitude ratio was neither correlated with the degree of endolymphatic hydrops nor with the duration of disease. While an older age was associated with a diminished amplitude ratio in healthy controls, there was no correlation between the amplitude ratio and age in Menière's ears. Hence, the calculation of the oVEMP 500/1000 Hz amplitude ratio may be a valuable diagnostic tool for Menière's disease.

  2. Introduction to Focus Issue: nonlinear and stochastic physics in biology.

    PubMed

    Bahar, Sonya; Neiman, Alexander B; Jung, Peter; Kurths, Jürgen; Schimansky-Geier, Lutz; Showalter, Kenneth

    2011-12-01

    Frank Moss was a leading figure in the study of nonlinear and stochastic processes in biological systems. His work, particularly in the area of stochastic resonance, has been highly influential to the interdisciplinary scientific community. This Focus Issue pays tribute to Moss with articles that describe the most recent advances in the field he helped to create. In this Introduction, we review Moss's seminal scientific contributions and introduce the articles that make up this Focus Issue.

  3. Stochastic longshore current dynamics

    NASA Astrophysics Data System (ADS)

    Restrepo, Juan M.; Venkataramani, Shankar

    2016-12-01

    We develop a stochastic parametrization, based on a 'simple' deterministic model for the dynamics of steady longshore currents, that produces ensembles that are statistically consistent with field observations of these currents. Unlike deterministic models, stochastic parameterization incorporates randomness and hence can only match the observations in a statistical sense. Unlike statistical emulators, in which the model is tuned to the statistical structure of the observation, stochastic parametrization are not directly tuned to match the statistics of the observations. Rather, stochastic parameterization combines deterministic, i.e physics based models with stochastic models for the "missing physics" to create hybrid models, that are stochastic, but yet can be used for making predictions, especially in the context of data assimilation. We introduce a novel measure of the utility of stochastic models of complex processes, that we call consistency of sensitivity. A model with poor consistency of sensitivity requires a great deal of tuning of parameters and has a very narrow range of realistic parameters leading to outcomes consistent with a reasonable spectrum of physical outcomes. We apply this metric to our stochastic parametrization and show that, the loss of certainty inherent in model due to its stochastic nature is offset by the model's resulting consistency of sensitivity. In particular, the stochastic model still retains the forward sensitivity of the deterministic model and hence respects important structural/physical constraints, yet has a broader range of parameters capable of producing outcomes consistent with the field data used in evaluating the model. This leads to an expanded range of model applicability. We show, in the context of data assimilation, the stochastic parametrization of longshore currents achieves good results in capturing the statistics of observation that were not used in tuning the model.

  4. Cognitive deficits in patients with a chronic vestibular failure.

    PubMed

    Popp, Pauline; Wulff, Melanie; Finke, Kathrin; Rühl, Maxine; Brandt, Thomas; Dieterich, Marianne

    2017-03-01

    Behavioral studies in rodents and humans have demonstrated deficits of spatial memory and orientation in bilateral vestibular failure (BVF). Our aim was to explore the functional consequences of chronic vestibular failure on different cognitive domains including spatial as well as non-spatial cognitive abilities. Sixteen patients with a unilateral vestibular failure (UVF), 18 patients with a BVF, and 17 healthy controls (HC) participated in the study. To assess the cognitive domains of short-term memory, executive function, processing speed and visuospatial abilities the following tests were used: Theory of Visual Attention (TVA), TAP Alertness and Visual Scanning, the Stroop Color-Word, and the Corsi Block Tapping Test. The cognitive scores were correlated with the degree of vestibular dysfunction and the duration of the disease, respectively. Groups did not differ significantly in age, sex, or handedness. BVF patients were significantly impaired in all of the examined cognitive domains but not in all tests of the particular domain, whereas UVF patients exhibited significant impairments in their visuospatial abilities and in one of the two processing speed tasks when compared independently with HC. The degree of vestibular dysfunction significantly correlated with some of the cognitive scores. Neither the side of the lesion nor the duration of disease influenced cognitive performance. The results demonstrate that vestibular failure can lead to cognitive impairments beyond the spatial navigation deficits described earlier. These cognitive impairments are more significant in BVF patients, suggesting that the input from one labyrinth which is distributed into bilateral vestibular circuits is sufficient to maintain most of the cognitive functions. These results raise the question whether BVF patients may profit from specific cognitive training in addition to physiotherapy.

  5. Genetics of Peripheral Vestibular Dysfunction: Lessons from Mutant Mouse Strains

    PubMed Central

    Jones, Sherri M.; Jones, Timothy A.

    2015-01-01

    Background A considerable amount of research has been published about genetic hearing impairment. Fifty to sixty percent of hearing loss is thought to have a genetic cause. Genes may also play a significant role in acquired hearing loss due to aging, noise exposure, or ototoxic medications. Between 1995 and 2012, over 100 causative genes have been identified for syndromic and nonsyndromic forms of hereditary hearing loss (see Hereditary Hearing Loss Homepage http://hereditaryhearingloss.org). Mouse models have been extremely valuable in facilitating the discovery of hearing loss genes, and in understanding inner ear pathology due to genetic mutations or elucidating fundamental mechanisms of inner ear development. Purpose Whereas much is being learned about hereditary hearing loss and the genetics of cochlear disorders, relatively little is known about the role genes may play in peripheral vestibular impairment. Here we review the literature with regard to genetics of vestibular dysfunction and discuss what we have learned from studies using mutant mouse models and direct measures of peripheral vestibular neural function. Results Several genes are considered that when mutated lead to varying degrees of inner ear vestibular dysfunction due to deficits in otoconia, stereocilia, hair cells, or neurons. Behavior often does not reveal the inner ear deficit. Many of the examples presented are also known to cause human disorders. Conclusions Knowledge regarding the roles of particular genes in the operation of the vestibular sensory apparatus is growing and it is clear that gene products co-expressed in the cochlea and vestibule may play different roles in the respective end organs. The discovery of new genes mediating critical inner ear vestibular function carries the promise of new strategies in diagnosing, treating and managing patients as well as predicting the course and level of morbidity in human vestibular disease. PMID:25032973

  6. Tonic Investigation Concept of Cervico-vestibular Muscle Afferents

    PubMed Central

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

    2016-01-01

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

  7. Prevalence of Vestibular Disorder in Older People Who Experience Dizziness

    PubMed Central

    Chau, Allan T.; Menant, Jasmine C.; Hübner, Patrick P.; Lord, Stephen R.; Migliaccio, Americo A.

    2015-01-01

    Dizziness and imbalance are clinically poorly defined terms, which affect ~30% of people over 65 years of age. In these people, it is often difficult to define the primary cause of dizziness, as it can stem from cardiovascular, vestibular, psychological, and neuromuscular causes. However, identification of the primary cause is vital in determining the most effective treatment strategy for a patient. Our aim is to accurately identify the prevalence of benign paroxysmal positional vertigo (BPPV), peripheral, and central vestibular hypofunction in people aged over 50 years who had experienced dizziness within the past year. Seventy-six participants aged 51–92 (mean ± SD = 69 ± 9.5 years) were tested using the head thrust dynamic visual acuity (htDVA) test, dizziness handicap inventory (DHI), as well as sinusoidal and unidirectional rotational chair testing, in order to obtain data for htDVA score, DHI score, sinusoidal (whole-body, 0.1–2 Hz with peak velocity at 30°/s) vestibulo-ocular reflex (VOR) gain and phase, transient (whole-body, acceleration at 150°/s2 to a constant velocity rotation of 50°/s) VOR gain and time constant (TC), optokinetic nystagmus (OKN) gain, and TC (whole-body, constant velocity rotation at 50°/s). We found that BPPV, peripheral and central vestibular hypofunction were present in 38 and 1% of participants, respectively, suggesting a likely vestibular cause of dizziness in these people. Of those with a likely vestibular cause, 63% had BPPV; a figure higher than previously reported in dizziness clinics of ~25%. Our results indicate that htDVA, sinusoidal (particularly 0.5–1 Hz), and transient VOR testing were the most effective at detecting people with BPPV or vestibular hypofunction, whereas DHI and OKN were effective at only detecting non-BPPV vestibular hypofunction. PMID:26733940

  8. Geographic Variation in Use of Vestibular Testing among Medicare Beneficiaries.

    PubMed

    Adams, Meredith E; Marmor, Schelomo; Yueh, Bevan; Kane, Robert L

    2017-02-01

    Objective There is a lack of consensus regarding the indications for vestibular testing in the evaluation of dizziness and balance disorders. Geographic variation in health services utilization is associated with lack of consensus. To understand the variation in current practice, we investigated the patterns of use of vestibular testing and diagnosis codes for dizziness and balance disorders among individuals ≥65 years of age across different regions of the United States. Study Design Cross-sectional study. Setting Medicare administrative claims data. Subjects and Methods Using the Summarized Denominator file, a sample of the US population linked to the Surveillance, Epidemiology, and End Results (SEER)-Medicare files (years 2000-2010), we identified persons who were ≥65 years of age. We used multivariable analyses to determine the factors associated with vestibular testing and diagnoses. Results Of the 231,984 eligible Medicare beneficiaries, 27% were diagnosed with dizziness and balance disorders. Patterns of use of vestibular tests (eye movement recording for spontaneous nystagmus, caloric testing, and rotary chair testing) varied significantly by geographic region. Rotary chair test utilization varied most. We found significant geographic variation in vestibular testing and diagnoses after controlling for age, sex, race, Medicaid participation, and rurality. Conclusions There may be opportunities to improve the consistency and efficiency of care for dizziness and balance disorders. It will be important to define appropriate levels of vestibular diagnostic testing and which tests add sufficient value to justify the costs. Further work is needed to better characterize the causes and consequences of variation in vestibular test utilization.

  9. 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.

  10. Prevalence of vestibular symptoms in individuals with auditory neuropathy spectrum disorder — A retrospective study

    PubMed Central

    Prabhu, Prashanth; Jamuar, Pratyasha

    2017-01-01

    Summary The objective of the study was to retrospectively determine the prevalence of vestibular symptoms in individuals with auditory neuropathy spectrum disorder (ANSD). It was also attempted to determine the prevalence of vestibular symptoms and factors (gender and age of reported hearing loss) that could affect the prevalence in individuals with ANSD. The vestibular symptoms reported in the case history were analyzed in individuals diagnosed with ANSD. The symptoms reported by a total of 316 individuals (185 females and 131 males) with ANSD were analyzed. The result of the study showed that one in five individuals with ANSD reported at least one of the vestibular symptom. The vestibular symptoms were in more females and in individuals with earlier onset of hearing loss. The result of the study supports that there is a vestibular damage in individuals with ANSD. However, it is essential to carry out prospective studies validating these vestibular symptoms with objective vestibular tests before generalizing the results. PMID:28357181

  11. Stochastic Convection Parameterizations

    NASA Technical Reports Server (NTRS)

    Teixeira, Joao; Reynolds, Carolyn; Suselj, Kay; Matheou, Georgios

    2012-01-01

    computational fluid dynamics, radiation, clouds, turbulence, convection, gravity waves, surface interaction, radiation interaction, cloud and aerosol microphysics, complexity (vegetation, biogeochemistry, radiation versus turbulence/convection stochastic approach, non-linearities, Monte Carlo, high resolutions, large-Eddy Simulations, cloud structure, plumes, saturation in tropics, forecasting, parameterizations, stochastic, radiation-clod interaction, hurricane forecasts

  12. A Stochastic Employment Problem

    ERIC Educational Resources Information Center

    Wu, Teng

    2013-01-01

    The Stochastic Employment Problem(SEP) is a variation of the Stochastic Assignment Problem which analyzes the scenario that one assigns balls into boxes. Balls arrive sequentially with each one having a binary vector X = (X[subscript 1], X[subscript 2],...,X[subscript n]) attached, with the interpretation being that if X[subscript i] = 1 the ball…

  13. 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.

  14. [Modern means of statokinetic improvement and vestibular rehabilitation].