Search results for "VESTIBULAR"
showing 10 items of 183 documents
Functional Plasticity after Unilateral Vestibular Midbrain Infarction in Human Positron Emission Tomography.
2016
The aim of the study was to uncover mechanisms of central compensation of vestibular function at brainstem, cerebellar, and cortical levels in patients with acute unilateral midbrain infarctions presenting with an acute vestibular tone imbalance. Eight out of 17 patients with unilateral midbrain infarctions were selected on the basis of signs of a vestibular tone imbalance, e.g., graviceptive (tilts of perceived verticality) and oculomotor dysfunction (skew deviation, ocular torsion) in F18-fluordeoxyglucose (FDG)-PET at two time points: A) in the acute stage, and B) after recovery 6 months later. Lesion-behavior mapping analyses with MRI verified the exact structural lesion sites. Group su…
Sensory Reweighting During Bipedal Quiet Standing in Adolescents
2020
A cross-sectional, prospective, between-subjects design was used in this study to establish the differences in sensory reweighting of postural control among different ages during adolescence. A total of 153 adolescents (five age groups; 13–17 years old) performed bipedal standing in three sensory conditions (i.e., with visual restriction, vestibular disturbance, and proprioceptive disturbance). Center of pressure displacement signals were measured in mediolateral and anteroposterior directions to characterize reweighting in the sensory system in static postural control when sensory information is disturbed or restricted during adolescent growth. The results indicate a development of postura…
Action Representation in Patients with Bilateral Vestibular Impairments
2011
During mental actions subjects feel themselves performing a movement without any corresponding motor output. Although broad information is available regarding the influence of central lesions on action representation, little is known about how peripheral damages affect mental events. In the current study, we investigated whether lack of vestibular information influences action representation. Twelve healthy adults and twelve patients with bilateral vestibular damage actually performed and mentally simulated walking and drawing. The locomotor paths implied one (first walking task) and four (second walking task) changes in the walking direction. In the drawing task, participants drew on a she…
A Pathway in the Brainstem for Roll-Tilt of the Subjective Visual Vertical: Evidence from a Lesion–Behavior Mapping Study
2012
The perceived subjective visual vertical (SVV) is an important sign of a vestibular otolith tone imbalance in the roll plane. Previous studies suggested that unilateral pontomedullary brainstem lesions cause ipsiversive roll-tilt of SVV, whereas pontomesencephalic lesions cause contraversive roll-tilts of SVV. However, previous data were of limited quality and lacked a statistical approach. We therefore tested roll-tilt of the SVV in 79 human patients with acute unilateral brainstem lesions due to stroke by applying modern statistical lesion–behavior mapping analysis. Roll-tilt of the SVV was verified to be a brainstem sign, and for the first time it was confirmed statistically that lesions…
Vestibular compensation in cerebellar stroke patients.
2014
Background and purpose There is little evidence about the site where compensatory vestibular mechanisms in patients with cerebellar strokes take place. Methods To determine whether the location of a cerebellar lesion might be a crucial variable in vestibular compensation a sample of 22 patients with cerebellar stroke were tested for graviceptive function in the acute and chronic stage. Results Our statistical anatomical lesion analysis indicated that mainly lesions of the cerebellar hemispheres (lobule V, VI, VIIa) hinder vestibular compensation and might lead to an overcompensation. Conclusions Overcompensation-induced dysfunction can be explained by the absence of cerebellar inhibitory si…
Who is at risk for ongoing dizziness and psychological strain after a vestibular disorder?
2009
Patients with vestibular vertigo syndromes often suffer from anxiety and depression, whereas patients with psychiatric disorders often experience subjective unsteadiness, dizziness, or vertigo. Thus, it has been hypothesized that the vestibular system may be interlinked with the emotion processing systems. The aim of the current study was to evaluate this hypothesis by correlating vestibular and psychiatric symptoms with the course of the disease over 1 year. This interdisciplinary, prospective, longitudinal study included a total of 68 patients with acute vestibular vertigo syndromes. Four subgroups of patients with benign paroxysmal positioning vertigo (BPPV, n=19), acute vestibular neuri…
Clinical and molecular spectrum of renal malformations in Kabuki syndrome.
2013
International audience; OBJECTIVE: To determine the frequency and types of renal malformations, and to evaluate renal function in a cohort of patients with Kabuki syndrome (KS). STUDY DESIGN: Renal ultrasound scans and plasma creatinine measurements were collected from a French cohort of 94 patients with genotyped KS. Renal function was evaluated based on the estimated glomerular filtration rate. A genotype-phenotype study was conducted for renal and urinary tract malformations. RESULTS: Renal malformations were present in 22% of cases, and urinary tract anomalies were present in 15%. Renal malformations were observed in 28% of the MLL2 mutation-positive group and in 0% of the MLL2 mutation…
Postural control and balance in a cohort of healthy people living in Europe: An observational study
2018
Abstract In the past 20 years, posturography has been widely used in the medical field. This observational study aimed to report the values derived from posturography of a wide set of healthy subjects from various European countries using a plantar pressure platform and a standardized method of measurement. A random cluster sampling of 914 healthy subjects aged between 7.0 and 85.99 years, stratified by age, was carried out. To provide percentile values of our cohort, data were processed to obtain 3 curves corresponding to the following percentiles: 25th, 50th, 75th, and the interquartile range. Distance-weighted least squares method was used to represent the percentile on appropriate graph…
Fractal analyses reveal independent complexity and predictability of gait
2017
Locomotion is a natural task that has been assessed since decades and used as a proxy to highlight impairments of various origins. Most studies adopted classical linear analyses of spatio-temporal gait parameters. Here, we use more advanced, yet not less practical, non-linear techniques to analyse gait time series of healthy subjects. We aimed at finding more sensitive indexes related to spatio-temporal gait parameters than those previously used, with the hope to better identify abnormal locomotion. We analysed large-scale stride interval time series and mean step width in 34 participants while altering walking direction (forward vs. backward walking) and with or without galvanic vestibular…
Metabolic changes in vestibular and visual cortices in acute vestibular neuritis
2004
Five right-handed patients with a right-sided vestibular neuritis were examined twice with fluorodeoxyglucose positron emission tomography while lying supine with eyes closed: once during the acute stage (mean, 6.6 days) and then 3 months later when central vestibular compensation had occurred. Regional cerebral glucose metabolism (rCGM) was significantly increased (p <0.001 uncorrected) during the acute stage in multisensory vestibular cortical and subcortical areas (parietoinsular vestibular cortex in the posterior insula, posterolateral thalamus, anterior cingulate gyrus [Brodmann area 32/24], pontomesencephalic brainstem, hippocampus). Simultaneously, there was a significant rCGM decrea…