Search results for "VESTIBULAR"

Ocular counterrolling. Some practical considerations of a new evaluation method for diagnostic purposes.

1986

Ocular counterrolling (OCR) data taken from the literature (12 publications) were used to test the best fit (least-square fit) of these measurements with respect to three mathematical models: a sine relation between OCR and the lateral tilt stimulus, a complex cosine-square relation, and a logarithmic relation between OCR gain and tilt. The latter proved to be the best fitting function. On the basis of this model, we attempted to define a physiological transfer function between OCR gain and tilt, which could serve as a reference of normal population, assuming healthy subjects for the investigations applied. Comparison of this physiological range with pathological data demonstrated marked di…

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…

Distribution of bradykinin B2 receptors in sheep brain and spinal cord visualized by in vitro autoradiography

1997

Bradykinin B2 receptors were localized in the sheep brain and spinal cord by quantitative in vitro autoradiography using a radiolabelled and specific bradykinin B2 receptor antagonist analogue, 3-4-hydroxyphenyl-propionyl-D-Arg0-[Hyp3,Thi5,D-Tic 7,Oic8]bradykinin, (HPP-HOE 140). This radioligand displays high affinity and specificity for bradykinin B2 receptors. The respective K(i) values of 0.32, 1.37 and 156 nM were obtained for bradykinin, HOE140 and D-Arg[Hyp3,D-Phe7,Leu8]bradykinin competing for radioligand binding to lamina II of sheep spinal cord sections. Using this radioligand, we have demonstrated the distribution of bradykinin B2 receptors in many brain regions which have not bee…

P13. Compensation processes for central vestibular dysfunction in patients with acute medullary infarctions (FDG-PET study)

2007

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…

Evolution of migraine vertigo in overlapping syndrome with ménière’s disease: Prognostic role of instrumental examination

2021

Migraine vertigo (MV) and Ménière's disease (MD) share several signs and symptoms such as tinnitus, fullness, photophobia, phonophobia, headache and vertigo spells lasting hours.The aim of the present study was to prospectively observe patients with MV with a sporadic audiological symptom evaluated with clinical examination, Vestibular Evoked Myogenic Potentials (VEMPs), ECochG and v-HIT.The finding of VEMP asymmetry, according to our cut-off of 33% of difference between sides, resulted in 20 cases, of which 6 had asymmetry of both c-VEMPs and o-VEMPS, all with development of fluctuating hearing during follow-up. ECochG was positive for endolymphatic hydrops in 12 patients.The evolution of …

Vertigo and multiple sclerosis: aspects of differential diagnosis.

2002

Equilibrium disorders caused by involvement of brainstem and cerebellar structures are common in patients with multiple sclerosis (MS), but peripheral conditions such as benign paroxysmal positional vertigo (BPPV) can be sometimes confused with those of a central origin. Therefore, an accurate otoneurologic investigation paying attention to differential diagnosis aspects should be performed in these subjects. Among available diagnostic tools, electro-oculography, posturography and vestibular evoked myogenic potentials (VEMPs) are especially suited to assess vestibulo-oculomotor and vestibulospinal systems. This paper briefly describes the most recent otoneurologic diagnostic strategies for …

Vestibular dysfunction in major depression

2007

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…