Search results for "vestibular system"
showing 10 items of 120 documents
Benign paroxysmal positional vertigo as a complication of osteotome expansion of the maxillary alveolar ridge.
2001
Benign paroxysmal positional vertigo (BPPV) is a common vestibular end organ disorder characterized by short, often recurrent episodes of vertigo that are triggered by certain head movements in the plane of the posterior semicircular canals. BPPV may be idiopathic or secondary to a number of underlying conditions such as head injury, viral labyrinthitis, stapes surgery, and chronic suppurative otitis media. 1,2 The most commonly accepted theory postulates the development of BPPV as a result of canalolithiasis, 3 heavy, inorganic particles detached from the otoconial layer by degeneration or head trauma gravitate into the posterior semicircular canal and act as a plunger on the endolymph and…
Functional brain imaging: a window into the visuo-vestibular systems
2007
Advances have been made in identifying how areas involved in processing vestibular, ocular motor, and visual information are represented in the human cortex as well as the cortical interaction between these systems in healthy subjects.While we know how some vestibular and ocular motor disorders modify visuo-vestibular interaction by changing the 'normal' cortical activation-deactivation patterns, it is still early days in functional magnetic resonance imaging studies of patients with specific disorders. Findings from current brain imaging studies of several vestibular, ocular motor, and cerebellar disorders are presented.The promise of more insights into the complex neuronal networks of the…
European vestibular experiments on the Spacelab-1 mission: 7. Ocular counterrolling measurements pre- and post-flight.
1986
The static ocular counterrolling (OCR) of the four scientific crew members in the first Spacelab mission was measured during baseline-data-collection before and after the flight of SL-1. It was presumed that the modification of otolithic responses during spaceflight will be reflected in specific changes of the OCR-gain on the first days after recovery. The magnitude of OCR was determined analysing colour-transparencies of subjects right eyes that were produced in different positions of lateral body tilt. In general, one subject did not show any changes at all; three subjects exhibited a significant decrease of OCR-gain after exposure to weightlessness, whereby differences could be found bet…
Vestibular Function after Acoustic Neuroma Removal with Preservation of One Branch of the Vestibular Nerve
2002
Background Vestibular compensation after acoustic neuroma surgery is affected by many parameters. Apart from surgical approach, age of the patient, and comorbidity, the use of rehabilitative vestibular training and the degree of preoperative vestibular compensation play their respective roles. Objective To examine whether and how surgical preservation of one branch of the vestibular nerve affects the compensation process in patients after acoustic neuroma removal. Study design Prospective study involving 29 patients with acoustic neuromas. In 15 patients operated on by the middle fossa or retrosigmoid approach, one branch of the vestibular nerve could be preserved intraoperatively, and the …
Vestibular compensation of otolith graviceptive dysfunction in stroke patients
2022
BACKGROUND AND PURPOSE A sensitive and frequent clinical sign of a vestibular tone imbalance is the tilt of the perceived subjective visual vertical (SVV). There are no data yet focusing on lesion location at the cortical level as a factor for predicting compensation from the tilt of the SVV. METHODS With modern voxelwise lesion behavior mapping analysis, the present study determines whether lesion location in 23 right-hemispheric cortical stroke patients with an otolith dysfunction could predict the compensation of a vestibular tone imbalance in the chronic stage. RESULTS Our statistical anatomical lesion analysis revealed that lesions of the posterior insular cortex are involved in vestib…
Why Do Subjective Vertigo and Dizziness Persist over One Year after a Vestibular Vertigo Syndrome?
2009
The overlap and interlinkage of dizzy symptoms in patients with psychiatric and vestibular vertigo/dizziness disorders is the subject of an ongoing debate. In a one-year follow up in 68 patients with vestibular vertigo syndromes, the persistency of vertigo and dizziness symptoms was examined and correlated with vestibular parameters and results from a psychiatric evaluation. Patients with vestibular migraine showed poorest improvement of vertigo and dizziness symptoms over time. In addition, patients who developed anxiety or depressive disorder after the onset of the vestibular disorder showed poor improvement and high persistency of symptoms.
Effects of rectilinear acceleration and optokinetic and caloric stimulations in space.
1984
During the flight of Spacelab 1 the crew performed a number of experiments to explore changes in vestibular function and visual-vestibular interactions on exposure to microgravity. Measurements were made on the threshold for detection of linear oscillation, vestibulo-ocular reflexes elicited by angular and linear movements, oculomotor and posture responses to optokinetic stimulations, and responses to caloric stimulation. Tests were also conducted on the ground, during the 4 months before and on days 1 to 6 after flight. The most significant result was that caloric mystagmus of the same direction as on the earth could also be evoked in the weightless environment.
European vestibular experiments on the Spacelab-1 mission: 1. Overview.
1986
During the flight of Spacelab-1 a series of vestibular experiments was performed on the crew by a group of European investigators. Control experiments were carried out on the same subjects pre- and postflight. The tests included caloric stimulation of the ears, threshold measurements of response to linear acceleration, motion sickness provocative stimuli, vestibulo-ocular reflexes during linear and angular stimulation, estimation of the subjective vertical (luminous line measurements) and static ocular counterrotation at various tilt angles. The caloric experiment proved the existence of a nonthermoconvective mechanism of caloric nystagmus in space. Most of the other test results point to a…
Electronystagmography in the diagnosis of central vertigo.
2011
Objective: Determine the efficacy and applicability of electronystagmography (ENG) testing in the differential diagnosis between peripheral and central vertigo, through the visual-vestibular interaction test, in patients with vertigo.Method: Patients were submitted to ENG recording. Patients sat on a rotatory chair, which was placed in the middle of a rotary rotatory cylindrical chamber. The rotatory chamber was driven by a direct current engine, which turned it clockwise and counterclockwise, and its internal area was covered with 32 black vertical contrast.Results: All patients underwent rotatory vestibular stimulation by Stop test (VOR), optokinetic stimulation (OKN), and contemporary ro…
Predictors of visually induced motion sickness in women
2019
Abstract Background Visually induced motion sickness (VIMS) is commonly experienced when visual motion information is in conflict with motion information provided by the vestibular system and/or tactile and kinesthetic senses. According to some studies, women experience higher levels of VIMS than men, whereas other studies do not find this to be the case. Hypothesis This study investigated whether gender differences can be attributed to changes in VIMS-susceptibility due to the menstrual cycle and perceived menstrual pain. We hypothesized that higher perceived menstrual pain correlates positively with VIMS susceptibility. Methods We measured the influence of estimated concentrations of four…