Search Results
Results 201 - 250 of 1325
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Nelson Eliza L - - 2009
Previous studies in human and chimpanzee infants have identified a predictive relationship between early rightward head orientation and later right hand use. Data from lemurs suggest a leftward bias in hand preference, but there are no data on head positioning. The purpose of this study was to examine the relationship ...
Zhong Dingyong - - 2009
A strategy for designing and activating surface-mounted molecular rotors with variable rotation radii and functional groups is proposed and demonstrated. The key point of the strategy is to separate the anchor and the rotating functional group from each other by using a connector of adjustable length. The three independent parts ...
Pfister Bryan J BJ Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ 07103, USA. - - 2009
The risk of traumatic brain injury (TBI) while riding roller coasters has received substantial attention. Case reports of TBI around the time of riding roller coasters have led many medical professionals to assert that the high gravitational forces (G-forces) induced by roller coasters pose a significant TBI risk. Head injury ...
Cox Philip G - - 2010
The semicircular canals of the inner ear sense angular accelerations and decelerations of the head and enable co-ordination of posture and body movement, as well as visual stability. Differences of agility and spatial sensitivity among species have been linked to interspecific differences in the relative size of the canals, particularly ...
Aoki Sachiko - - 2009
CONCLUSIONS: The caloric test with head-tilt can be used as a tool for assessing vertical canal function as an office procedure. OBJECTIVE: Evaluation of vertical canal function. PATIENTS AND METHODS: We provoked caloric response by cold water in the vertiginous patients in supine position. During the culmination of the response ...
Falvo Michael J MJ Washington University School of Medicine, Saint Louis, Missouri 63108, - - 2009
Active countercircling on a rotating platform for 15 min causes individuals to involuntarily circle in the same direction when they step in place on firm ground. This is referred to as podokinetic after-rotation (PKAR). It is unclear how interjecting brief periods of visual or haptic inputs for a stable orientation ...
Clément Gilles - - 2010
Four patients following unilateral vestibular loss and four patients complaining of otolith-dependent vertigo were tested during eccentric yaw rotation generating 1 x g centripetal acceleration directed along the interaural axis. Perception of body tilt in roll and in pitch was recorded in darkness using a somatosensory plate that the subjects ...
Neely Kristina A KA School of Kinesiology, The University of Western Ontario, 3M Centre, Room 2230, 1151 Richmond Street North, London, ON, N6A 3K7, Canada. - - 2010
In the visuomotor mental rotation (VMR) paradigm, participants execute a center-out reaching movement to a location that deviates from a visual cue by a predetermined instruction angle. Previous work has demonstrated a linear increase in reaction time (RT) as a function of the amplitude of the instruction angle (Georgopoulos and ...
Altmann Christian F - - 2009
Under natural conditions, our sound localization capabilities enable us to move constantly while keeping a stable representation of our auditory environment. However, since most auditory studies focus on head-restrained conditions, it is still unclear whether neurophysiological markers of auditory spatial processing reflect representation in a head-centered or an allocentric coordinate ...
Woodhouse Astrid A Department of Public Health and General Practice, Norwegian University of Science and Technology, Trondheim, Norway. - - 2010
Patients with whiplash associated disorders (WAD) have shown less accuracy in trajectory head motion compared to asymptomatic controls, which comply with clinical observations. The aim of this study was to investigate whether a trajectory head movement task can differ between WAD patients, chronic non-traumatic neck pain (CNP) patients and asymptomatic ...
Ji Jennifer T T - - 2009
OBJECTIVE: This study investigates isolated effects of vection and optokinetic nystagmus (OKN) on visually induced motion sickness (VIMS) provoked by rotating optokinetic drum patterns. BACKGROUND: VIMS was the subject of recent standardization activities, but the effects of OKN have not been studied in the absence ofvection. METHOD: Experiment 1 suppressed ...
Bruggeman Hugo - - 2009
When turning without vision or audition, people tend to perceive their locomotion as a change in heading relative to objects in the remembered surroundings. Such perception of self-rotation depends on sensitivity to information for movement from biomechanical activity of the locomotor system or from inertial activation of the vestibular and ...
Nam E-C EC Department of Otolaryngology, School of Medicine, Kangwon National University, Chunchon, South - - 2010
Superior semicircular canal dehiscence affects the auditory and vestibular systems due to a partial defect in the canal's bony wall. In most cases, sound- and pressure-induced vertigo are present, and are sometimes accompanied by pulse-synchronous tinnitus. We describe a 50-year-old man with superior semicircular canal dehiscence whose only complaints were ...
Hammerberg Eric Mark - - 2010
Femoral head sizes greater than 32 mm are more prevalent with current total hip arthroplasty. We hypothesized that linear wear rates of Durasul highly cross-linked polyethylene would not differ with different head sizes. We also compared the range of motion of the hip. Ninety-four consecutive arthroplasties in 84 patients were ...
Sadeghi Soroush G - - 2009
Mechanical occlusion (plugging) of the slender ducts of semicircular canals has been used in the clinic as well as in basic vestibular research. Here, we investigated the effect of canal plugging in two macaque monkeys on the horizontal vestibuloocular reflex (VOR) and the responses of vestibular-nerve afferents during passive head ...
Campobasso Carlo P - - 2009
A mummified body of an 86-year-old white man with a history of coronary atherosclerosis was found in the reception-room of his apartment located in a condominium of the city-center of Bari (Southern Italy) approximately 7 years after disappearance. Unpaid electricity bills caused the power stations to turn off electricity while ...
Cheng Po-Wen - - 2009
OBJECTIVE: This study compared the characteristic parameters of ocular vestibular-evoked myogenic potentials (oVEMPs) elicited by the air-conducted sound (ACS) and bone-conducted vibration (BCV) stimulation modes as well as the galvanic vestibular stimulation (GVS) mode. DESIGN: Fifteen healthy subjects underwent oVEMP tests using ACS (127 dBSPL), BCV (142dB force level), and ...
Vidal Manuel M Max Planck Institute for Biological Cybernetics, Tübingen, Germany. - - 2010
Many previous studies have focused on how humans combine inputs provided by different modalities for the same physical property. However, it is not yet very clear how different senses providing information about our own movements combine in order to provide a motion percept. We designed an experiment to investigate how ...
Yakushin Sergei B - - 2009
Little is known about the dependence of the roll angular vestibuloocular reflex (aVOR) on gravity or its gravity-dependent adaptive properties. To study gravity-dependent characteristics of the roll aVOR, monkeys were oscillated about a naso-occipital axis in darkness while upright or tilted. Roll aVOR gains were largest in the upright position ...
Ivancic Paul C - - 2009
BACKGROUND: Previous epidemiological studies have observed that an initial head restraint backset greater than 10 cm is associated with a higher risk of neck injury and persistent symptoms. The objective of this study was to investigate the relation between the active head restraint position and peak neck motion using a ...
Sugita-Kitajima Akemi - - 2009
To evaluate the influence of somatosensory input on the vestibulo-ocular reflex (VOR), we used sinusoidal rotation tests in 19 young, healthy volunteers. For the control condition, subjects were sinusoidally rotated in complete darkness and with eyes opened at a frequency of 0.2 Hz with a maximum angular velocity of 30 ...
Rader A A AA Department of Aeronautics and Astronautics, Man Vehicle Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts, - - 2009
Using a variable-radius roll swing motion paradigm, we examined the influence of interaural (y-axis) and dorsoventral (z-axis) force modulation on perceived tilt and translation by measuring perception of horizontal translation, roll tilt, and distance from center of rotation (radius) at 0.45 and 0.8 Hz using standard magnitude estimation techniques (primarily ...
Hudson Matthew - - 2009
Using a representational momentum paradigm, this study investigated the hypothesis that judgments of how far another agent's head has rotated are influenced by the perceived gaze direction of the head. Participants observed a video-clip of a face rotating 60 degrees towards them starting from the left or right profile view. ...
Fourre Beno??t - - 2009
We examined to which extent proprioceptive information involved in the perception of subjective vertical corresponded to mechanical mass-based axes of the body. Blindfolded subjects (n=14) estimated their subjective vertical in conditions of deviation of the centre of mass (CM) of (1) the head-trunk unit or (2) the head segment alone. ...
Bode Hans R - - 2009
Morphogen gradients play an important role in pattern formation during early stages of embryonic development in many bilaterians. In an adult hydra, axial patterning processes are constantly active because of the tissue dynamics in the adult. These processes include an organizer region in the head, which continuously produces and transmits ...
Sugita-Kitajima Akemi - - 2009
The vestibulo-ocular reflex (VOR) was studied to examine the utility of off-vertical axis rotation (OVAR) in the diagnosis of acoustic neurinoma. Subjects were sinusoidally rotated with eyes open in complete darkness at frequencies of 0.4 and 0.8 Hz with a maximum angular velocity of 60 degrees /s at either earth-vertical ...
Ceyte Hadrien - - 2009
The majority of previous studies which have explored the mechanisms underlying perception of the direction of gravity in static roll tilt have proposed that the tendency to estimate the subjective visual vertical (SVV) as tilted towards body tilt ('Aubert effect') arises from an underestimation of perceived body tilt. The present ...
Rabbitt Richard D RD Department of Bioengineering, University of Utah, 72 South Central Campus Dr., Rm. 2646, Salt Lake City, UT, 84112, USA. - - 2009
The dynamic displacement of the semicircular canal cupula and modulation of afferent nerve discharge were measured simultaneously in response to physiological stimuli in vivo. The adaptation time constant(s) of normal cupulae in response to step stimuli averaged 36 s, corresponding to a mechanical lower corner frequency for sinusoidal stimuli of ...
Golding John F JF Department of Psychology, University of Westminster, 309 Regent Street, London W1B 2UW, UK. - - 2009
Off-vertical axis rotation (OVAR) causes motion sickness which increases with angle of tilt and is most provocative around 0.2 Hz. The aim was to determine the tilt angle and frequency characteristics for visual OVAR, which is also known to be nauseogenic. A computerized scene, as seen by a pilot at ...
Quarck Gaelle G INSERM ERI 27, Univ Caen, Caen, France. - - 2009
In order to explore the effect of gaze orientation on whole-body rotation perception, ten healthy participants were rotated in the dark while fixating on a visual target located either straight ahead or 15 degrees to the right. A vestibular-memory contingent saccade paradigm was used to estimate the rotation perception. The ...
Dai Mingjia M Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029, USA. - - 2009
Head movements in a rotating frame of reference are commonly encountered, but their long term effects on the angular vestibulo-ocular reflex (aVOR) are not well understood. To study this, monkeys were oscillated about a naso-occipital (roll) axis for several hours while rotating about a spatial vertical axis (roll-while-rotating, RWR). This ...
Minnebusch Denise A - - 2009
The present study aimed to further explore the mechanisms underlying the perception of human body shapes. Behavioral and electrophysiological inversion effects were studied for human bodies with and without heads and for animal bodies (cats, dogs, and birds). Recognition of human bodies (with heads) was adversely affected by stimulus inversion, ...
Seidman Scott H - - 2009
In response to translations of the head, the linear vestibulo-ocular reflex (LVOR) produces compensatory eye movements that are high-pass in nature, with a declining response magnitude and an increasing phase lead with declining stimulus frequency. Perception of head translation, however, is reported to be robust at much lower frequency than ...
Straka Hans - - 2009
Self-generated locomotor activity is accompanied by head movements that cause retinal image displacements with a resultant degradation of visual information processing. To maintain visual acuity, retinal image drift must be counteracted by dynamic compensatory gaze adjustments that derive to a large extent from vestibulo-ocular reflexes (VOR). During head motion, vestibular ...
Wood S J - - 2009
CONCLUSION: The pitch plane vestibulo-ocular reflex (VOR) gain and symmetry at low frequencies (< or =0.3 Hz) are enhanced by otoliths and/or somatosensory sensory cues during combined angular and linear stimuli. We conclude that neural processing of these linear motion cues is used to improve the VOR when stimulus frequencies ...
Cohen Bernard - - 2009
The vestibular system plays an important role in controling gait, but where in the labyrinths relevant activity arises is largely unknown. After the semicircular canals are plugged, low frequency (0.01-2 Hz) components of the angular vestibulo-ocular reflex (aVOR) and angular vestibulo-collic reflex (aVCR) are lost, but high frequency (3-20 Hz) ...
Schneider Erich - - 2009
Human head rotation in roll around an earth-horizontal axis constitutes a vestibular stimulus that, by its rotational component, acts on the semicircular canals (SCC) and that, by its tilt of the gravity vector, also acts on the otoliths. Galvanic vestibular stimulation (GVS) is thought to resemble mainly a rotation in ...
Choi Kwang-Dong - - 2009
Mechanisms of head-shaking nystagmus (HSN) require further exploration in central vestibular disorders. To determine whether impaired uvulonodular inhibition over the velocity storage of the vestibulo-ocular reflex (VOR) is the mechanism of ipsilesional HSN in lateral medullary infarction (LMI), 17 patients with ipsilesional HSN and LMI underwent measurements of the VOR ...
De Cocq P - - 2009
REASON FOR PERFORMING STUDY: During trot, the rider can either rise from the saddle during every stride or remain seated. Rising trot is used frequently because it is widely assumed that it decreases the loading of the equine back. This has, however, not been demonstrated in an objective study. OBJECTIVE: ...
Bardins Stanislavs - - 2009
Locomotion control uses proprioceptive, visual, and vestibular signals. Previously, we analyzed the visual contribution with visual motion stimulation in roll while participants kept their heads in a normal upright orientation. In this study we applied the same visual disturbance in a head-upright and a nose-down condition. Random dot patterns were ...
Yakushin Sergei B SB Departments of Neurology, Mount Sinai School of Medicine, New York, New York 10029, USA. - - 2009
The cervico-ocular reflex (COR) has a low gain in normal animals. In this study, we determined whether COR gain increases were specific to the low/midband frequency range, which is the range over which the angular vestibulo-ocular reflex (aVOR) is compromised by plugging. The gain and phase of the yaw and ...
Guenther Anna L - - 2009
Humans can discriminate whether a change in the direction of gravito-inertial force (GIF) is caused by body tilt or by linear translation. This ability, attributed to vestibular sensory fusion, is often examined by asking subjects to adjust an indicator to match their subjective earth-fixed vertical (SV). We used two different ...
Lackner James R JR Ashton Graybiel Spatial Orientation Laboratory, Brandeis University, Waltham, MA 02454-9110, USA. - - 2009
We had recumbent subjects (n = 7) indicate the amplitude of imposed, passive yaw-axis body rotations in the 0, 1, and 1.8 g background force levels generated during parabolic flight maneuvers. The blindfolded subject, restrained in a cradle, aligned a gravity-neutral pointer with the subjective vertical while in an initial ...
Todd Neil P M - - 2009
We recently reported that a major contribution to the low-frequency tuning and sensitivity of the human vestibular system is the biomechanical properties of the vestibular end-organs. In the current paper, we investigate the contribution of additional mechanisms to low-frequency tuning. We compared the response properties of the vestibular system in ...
Macpherson Ewan A - - 2009
Correspondence between head rotation and resulting changes in interaural difference cues provides information about sound source location. We assessed whether source continuity or merely relative displacement is necessary for use of this dynamic localization cue. Low-frequency (0.5-1 kHz) noise-band targets, not correctly localizable in the absence of head motion or ...
Rosner R - - 2009
Behavioural responses of an animal are variable even when the animal experiences the same sensory input several times. This variability can arise from stochastic processes inherent to the nervous system. Also, the internal state of an animal may influence a particular behavioural response. In the present study, we analyse the ...
Mapelli Andrea - - 2009
To assess the relative contribution of rotation and translation of the temporomandibular condyle-disc assembly during opening and closing movements, free movements of maximum mouth opening and closing were recorded in healthy subjects (12 men, 14 women) using an optoelectronic three-dimensional motion analyzer. For each subject, the displacement of the lower ...
Dannenbaum Elizabeth - - 2009
OBJECTIVES: The objectives of this study are threefold: 1) to examine the effect of frequency of head motion on the clinical dynamic visual acuity (DVA) score in subjects with unilateral vestibular hypofunction (UVH); 2) to compare DVA scores between subjects with UVH and subjects with a complete unilateral vestibular deficit; ...
Farber Adam J - - 2009
BACKGROUND: Commonly performed arthroscopic rotator interval closure techniques that imbricate the rotator interval in a superior-inferior direction have been unable to reproduce the stabilizing effects of an open medial-lateral rotator interval imbrication. HYPOTHESIS: The medial-lateral rotator interval closure will allow less inferior and posterior glenohumeral translation than the superior-inferior rotator ...
Rhodin M - - 2009
REASONS FOR PERFORMING STUDY: Dressage involves training of the horse with the head and neck placed in a position defined by the rider. The best position for dressage training is currently under debate among riders and trainers, but there are few scientific data available to confirm or disprove the different ...
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