Read by QxMD icon Read


Hina Garg, Leland E Dibble, Michael C Schubert, Jim Sibthorp, K Bo Foreman, Eduard Gappmaier
Despite the common complaints of dizziness and demyelination of afferent or efferent pathways to and from the vestibular nuclei which may adversely affect the angular Vestibulo-Ocular Reflex (aVOR) and vestibulo-spinal function in persons with Multiple Sclerosis (PwMS), few studies have examined gaze and dynamic balance function in PwMS. OBJECTIVES: 1) Determine the differences in gaze stability, dynamic balance and participation measures between PwMS and controls, 2) Examine the relationships between gaze stability, dynamic balance and participation...
May 5, 2018: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
Julia Dlugaiczyk, Michael Thiemer, Christian Neubert, Bianca Anna Schorn, Bernhard Schick
HYPOTHESIS: Implementation of the "aVOR app" into teaching courses at medical school enhances students' satisfaction with the course and increases their competence in treating benign paroxysmal positional vertigo (BPPV). BACKGROUND: BPPV is often underdiagnosed and left untreated. One problem in teaching the management of BPPV to health care professionals is the lack of simulation-based training tools. The aVOR app (aVOR = angular vestibulo-ocular reflex) works as a bionic labyrinth that simulates the activation of the semicircular canals by rotational acceleration and the resulting vestibular evoked eye movements...
June 2018: Otology & Neurotology
Nils Guinand, Raymond Van de Berg, Samuel Cavuscens, Maurizio Ranieri, Erich Schneider, Floor Lucieer, Herman Kingma, Jean-Philippe Guyot, Angélica Pérez Fornos
The purpose of this study was to evaluate whether it is possible to restore the high-frequency angular vestibulo-ocular reflex (aVOR) in patients suffering from a severe bilateral vestibulopathy (BV) and implanted with a vestibular implant prototype. Three patients (S1-3) participated in the study. They received a prototype vestibular implant with one to three electrode branches implanted in the proximity of the ampullary branches of the vestibular nerve. Five electrodes were available for electrical stimulation: one implanted in proximity of the left posterior ampullary nerve in S1, one in the left lateral and another one in the superior ampullary nerves in S2, and one in the right lateral and another one in the superior ampullary nerves in S3...
2017: Frontiers in Neurology
Jorge Rey-Martinez
To explore the applicability of discrete wavelet transforms in the analysis of vHIT responses. Discrete wavelet transform was applied to vHIT responses and a new method for calculating aVOR gain was developed. A prospective study was performed with two groups of normal (N = 10) and altered (N = 19) gain values; HIMP and SHIMP vHIT protocols were performed on both groups. To evaluate the gain values obtained, Intraclass Correlation Index, Pearson's correlation, linear regression, and t test were performed...
December 2017: European Archives of Oto-rhino-laryngology
Takao Imai, Yasumitsu Takimoto, Noriaki Takeda, Tomoko Okumura, Hidenori Inohara
When participants undergo eccentric rotation (ER), i.e., they are rotated while displaced from the axis of rotation, they undergo both rotational stimulation and linear acceleration, which induces both the angular vestibulo-ocular reflex (aVOR) and linear VOR (lVOR). During ER, the lVOR induced by tangential linear acceleration enhances the eye movement induced by aVOR. In this study, we attempted to measure aVOR and lVOR separately, while participants underwent ER while facing the ground in a dark room. We analyzed three-dimensional eye movements using a video-oculography system...
August 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Michael C Schubert, Americo A Migliaccio
OBJECTIVE: The angular vestibulo-ocular reflex (aVOR) is known to be influenced by factors such as arousal and cognition during traditional vestibular function testing. However, the inherent variability of the aVOR to head impulse testing has not been explicitly examined. The purpose of this study was to determine the variability of the aVOR to active and passive head impulses using the gold standard scleral search coil method to record head and eye rotation. STUDY DESIGN: Descriptive...
July 2016: Otology & Neurotology
Lynda Marie Ross, Janet Odry Helminski
OBJECTIVE: Determine reliability of horizontal and vertical video head impulse test (vHIT) and effect of maturation on angular vestibular ocular reflex (AVOR) gain estimations and peak head velocities of individual canals in typically developing children and adolescents. DESIGN: Reliability study. SETTING: University research laboratory SUBJECTS: : Two normal adults mean age 51.5 ± 0.5 years and 28 typically developing children and adolescents mean age 10 ± 3...
June 2016: Otology & Neurotology
Mina Ranjbaran, Henrietta L Galiana
The vestibulo-ocular reflex (VOR) is an involuntary eye movement evoked by head movements. It is also influenced by viewing distance. This paper presents a hybrid nonlinear bilateral model for the horizontal angular vestibulo-ocular reflex (AVOR) in the dark. The model is based on known interconnections between saccadic burst circuits in the brainstem and ocular premotor areas in the vestibular nuclei during fast and slow phase intervals of nystagmus. We implemented a viable switching strategy for the timing of nystagmus events to allow emulation of real nystagmus data...
2015: Frontiers in Computational Neuroscience
Michael C Schubert, Georgios Mantokoudis, Li Xie, Yuri Agrawal
BACKGROUND: Vestibular rehabilitation is a sub-specialization within the practice of physical therapy that includes treatments designed to reduce gaze instability. Gaze stability exercises are commonly given for head rotations to the left and right, even in subjects with one healthy vestibular system (as in unilateral loss). Few studies have investigated the difference in the angular vestibular ocular reflex gain (aVOR) measured in the acute phase after deafferentation for ipsilesional head rotations that move the head away from center or towards center...
2014: Journal of Vestibular Research: Equilibrium & Orientation
Luke Chen, Michael Todd, Gabor M Halmagyi, Swee Aw
OBJECTIVE: We sought to quantify and compare angular vestibulo-ocular reflex (aVOR) gain and compensatory saccade properties elicited by the head impulse test (HIT) in pontine-cerebellar stroke (PCS) and vestibular neuritis (VN). METHODS: Horizontal HIT was recorded ≤7 days from vertigo onset with dual-search coils in 33 PCS involving the anterior inferior, posterior inferior, and superior cerebellar arteries (13 AICA, 17 PICA, 3 SCA) confirmed by MRI and 20 VN...
October 21, 2014: Neurology
Michael Baxter, Yuri Agrawal
OBJECTIVE: Turner syndrome is a well-known cause of sensorineural hearing loss, and the lack of estrogen has been implicated in cochlear dysfunction. It has never been associated with vestibular dysfunction. We report a case of a patient with Turner syndrome who was found to have bilateral vestibular dysfunction based on video-oculography (VOG) testing. PATIENT: A single patient with a history of Turner syndrome who was found to have significant bilateral vestibular dysfunction...
February 2014: Otology & Neurotology
Paolo Colagiorgio, Silvia Colnaghi, Maurizio Versino, Stefano Ramat
Peripheral vestibular function may be tested quantitatively, by measuring the gain of the angular vestibulo-ocular reflex (aVOR), or functionally, by assessing how well the aVOR performs with respect to its goal of stabilizing gaze in space and thus allow to acquire visual information during the head movement. In recent years, several groups have developed clinical and quantitative approaches to functional testing of the vestibular system based on the ability to identify an optotype briefly displayed on screen during head rotations...
2013: Frontiers in Neurology
Chien-Cheng Chen, Christopher J Bockisch, Giovanni Bertolini, Itsaso Olasagasti, Stephan C F Neuhauss, Konrad P Weber, Dominik Straumann, Melody Ying-Yu Huang
The optokinetic reflex (OKR) and the angular vestibulo-ocular reflex (aVOR) complement each other to stabilize images on the retina despite self- or world motion, a joint mechanism that is critical for effective vision. It is currently hypothesized that signals from both systems integrate, in a mathematical sense, in a network of neurons operating as a velocity storage mechanism (VSM). When exposed to a rotating visual surround, subjects display the OKR, slow following eye movements frequently interrupted by fast resetting eye movements...
January 1, 2014: Journal of Physiology
Mina Ranjbaran, Henrietta L Galiana
A hybrid nonlinear bilateral model for the horizontal angular vestibulo-ocular reflex (AVOR) is presented in this paper. The model relies on known interconnections between saccadic burst circuits in the brainstem and ocular premotor areas in the vestibular nuclei during slow and fast phase intervals. A viable switching strategy for the timing of nystagmus events is proposed. Simulations show that this hybrid model replicates AVOR nystagmus patterns that are observed in experimentally recorded data.
2013: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Yuri Agrawal, Michael C Schubert, Americo A Migliaccio, David S Zee, Erich Schneider, Nadine Lehnen, John P Carey
OBJECTIVE: To evaluate the validity of 2D video-oculography (VOG) compared with scleral search coils for horizontal AVOR gain estimation in older individuals. STUDY DESIGN: Cross-sectional validation study. SETTING: Tertiary care academic medical center. PATIENTS: Six individuals age 70 and older. INTERVENTIONS: Simultaneous eye movement recording with scleral search coil (over right eye) and EyeSeeCam VOG camera (over left eye) during horizontal head impulses...
February 2014: Otology & Neurotology
A A Tarnutzer, A G Lasker, D S Zee
Sensory input from the semicircular canals (SCC) and otolith organs is centrally combined with signals from other sensory modalities to continuously update the internal estimate of self-motion. Constant velocity vertical on-axis rotation leads to decay of the nystagmus response from the horizontal SCC and of perceived angular velocity (PAV), and when the rotation stops, a similar oppositely directed post-rotatory response occurs. Case reports and electrical stimulation studies suggest an involvement of the temporo-peri-Sylvian vestibular cortex in generating the PAV...
October 2013: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Mina Ranjbaran, Henrietta L Galiana
A bilateral model for the horizontal angular vestibulo-ocular reflex (AVOR) is presented in this paper. It is shown that by assigning proper non-linear neural computations at the premotor level, the model is capable of replicating target-distance dependent VOR responses. Moreover, the model behavior in case of sensory plugging is also consistent with reported experimental observations.
2012: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Matthew R Scherer, Pedro J Claro, Kristin J Heaton
BACKGROUND: The risk of traumatic brain injury (TBI) and comorbid posttraumatic dizziness is elevated in military operational environments. Sleep deprivation is known to affect a service member's performance while deployed, although little is known about its effects on vestibular function. Recent findings suggest that moderate acceleration step rotational stimuli may elicit a heightened angular vestibulo-ocular reflex (aVOR) response relative to low-frequency sinusoidal stimuli after 26 hours of sleep deprivation...
September 2013: Physical Therapy
Americo A Migliaccio, Charles C Della Santina, John P Carey
Vergence is one of several viewing contexts that require an increase in the angular vestibular-ocular reflex (aVOR) response. A previous monkey study found that the vergence-mediated gain (eye/head velocity) increase of the aVOR was attenuated by 64 % when anodic currents, which preferentially lower the activity of irregularly firing vestibular afferents, were delivered to both labyrinths. We sought to determine whether there was similar evidence implicating a role for irregular afferents in the vergence-mediated gain increase of the human aVOR...
February 2013: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Yongqing Xiang, Sergei B Yakushin, Theodore Raphan
Gain adaptation of the yaw angular vestibular ocular reflex (aVOR) induced in side-down positions has gravity-independent (global) and -dependent (localized) components. When the head oscillation angles are small during adaptation, localized gain changes are maximal in the approximate position of adaptation. Concurrently, polarization vectors of canal-otolith vestibular neurons adapt their orientations during these small-angle adaptation paradigms. Whether there is orientation adaptation with large amplitude head oscillations, when the head is not localized to a specific position, is unknown...
July 2012: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"