Search results for "Nystagmu"

2018

Objectives: To evaluate the function of the oculomotor and vestibular systems and to correlate these findings with the clinical status of patients with Gaucher disease type 3 (GD3). The goal of this cross-sectional and longitudinal study was to find oculomotor biomarkers for future clinical trials. Methods: Twenty-six patients with GD3 were assessed for eligibility and 21 were able to perform at least one task. Horizontal and vertical reflexive saccades, smooth pursuit, gaze-holding, optokinetic nystagmus, and horizontal vestibulo-ocular reflex (VOR) were examined by video-oculography/video-head impulse test and compared concurrently with 33 healthy controls. The Scale for the Assessment an…

Visual-motion suppression in congenital pendular nystagmus.

2009

Patients with a congenital pendular nystagmus are known not to experience oscillopsia in a normal visual environment. The data of a 31-year-old female patient suffering from a congenital pendular nystagmus are presented. The aim of the fluorodeoxyglucose positron emission tomography (FDG-PET) experiment was to analyze the regional cerebral glucose metabolism (rCGM) during minimal as well as maximal nystagmus. Video-oculography showed a maximum in frequency of the horizontal pendular nystagmus during gaze to the left, whereas the zone of minimal nystagmus was 10 degrees to the right. Two sessions with an 18F-fluorodeoxyglucose tracer were performed to analyze cerebral blood-glucose utilizati…

Motion sickness induced by otolith stimulation is correlated with otolith-induced eye movements

2008

International audience; This article addresses the relationships between motion sickness (MS) and three-dimensional (3D) ocular responses during otolith stimulation. A group of 19 healthy subjects was tested for motion sickness during a 16 min otolith stimulation induced by off-vertical axis rotation (OVAR) (constant velocity 60 degrees /s, frequency 0.16 Hz). For each subject, the MS induced during the session was quantified, and based on this quantification, the subjects were divided into two groups of less susceptible (MS-), and more susceptible (MS+) subjects. The angular eye velocity induced by the otolith stimulation was analyzed in order to identify a possible correlation between sus…

Direction‐dependent visual cortex activation during horizontal optokinetic stimulation (fMRI study)

2005

Looking at a moving pattern induces optokinetic nystagmus (OKN) and activates an assembly of cortical areas in the visual cortex, including lateral occipitotemporal (motion‐sensitive area MT/V5) and adjacent occipitoparietal areas as well as ocular motor areas such as the prefrontal cortex, frontal, supplementary, and parietal eye fields. The aim of this functional MRI (fMRI) study was to investigate (1) whether stimulus direction‐dependent effects can be found, especially in the cortical eye fields, and (2) whether there is a hemispheric dominance of ocular motor areas. In a group of 15 healthy subjects, OKN in rightward and leftward directions was visually elicited and statistically compa…

fMRI signal increases and decreases in cortical areas during small-field optokinetic stimulation and central fixation

2001

Small-field optokinetic nystagmus (OKN) was performed in seven healthy volunteers in order to analyze the activation and deactivation patterns of visual motion, ocular motor, and multisensory vestibular cortex areas by means of fMRI during coherent visual motion stimulation. BOLD signal decreases (deactivations) were found in the first and second long insular gyri and retroinsular areas (the human homologue of the parietoinsular vestibular cortex and the visual posterior sylvian area in the monkey) of both hemispheres, extending into the transverse temporal gyrus and inferior-anterior parts of the superior temporal gyrus (BA 22), and the precentral gyri at two separate sites (BA 4 and 6). F…

Evidence for cortical visual substitution of chronic bilateral vestibular failure (an fMRI study).

2007

Bilateral vestibular failure (BVF) is a rare disorder of the labyrinth or the eighth cranial nerve which has various aetiologies. BVF patients suffer from unsteadiness of gait combined with blurred vision due to oscillopsia. Functional MRI (fMRI) in healthy subjects has shown that stimulation of the visual system induces an activation of the visual cortex and ocular motor areas bilaterally as well as simultaneous deactivations of multisensory vestibular cortex areas. Our question was whether the chronic absence of bilateral vestibular input (BVF) causes a plastic cortical reorganization of the above-described visual-vestibular interaction. We used fMRI to measure the differential effects of…

Torsional eye movement responses to monaural and binaural galvanic vestibular stimulation: side-to-side asymmetries.

2003

Vestibular stimulation by head accelerations always involves multisensory activation of the vestibular, somatosensory, and visual systems. Over the past few years, galvanic vestibular stimulation (GVS) has become increasingly popular for testing vestibular function for clinical and research purposes. Although GVS provides a nonphysiological stimulation, it is more selective than natural head accelerations and is thus an attractive tool for such tests. Eye movement responses elicited by GVS mainly consist of torsional and horizontal components, as first described by Hitzig in 1871. Animal experiments have shown that GVS increases the vestibular afferent spike frequency at the cathodal site a…

Static posturography with dynamic tests. Usefulness of biomechanical parameters in assessing vestibular patients.

2012

Abstract Introduction and objective Posturography allows us in evaluating postural control. This study showed the posturographic parameters that were useful for assessing the functional ability to maintain balance in our sample of vestibular patients. Material and methods Of a total of 89 patients, 59 were healthy subjects and 30 had a peripheral vestibular disorder. The subjects were studied using the posturographic NedSVE/IBV system, combining static (Romberg) and dynamic (stability limits and rhythmic weight shifts) tests. We then compared the measurements found in the groups. Results Normal subjects showed significantly lower oscillations than our patients in all of the posturographic p…

Benign paroxysmal positional vertigo following whiplash injury: a myth or a reality?

2011

Abstract Objective The aim of the study was to evaluate the true incidence, diagnosis, and treatment of benign paroxysmal positional vertigo (BPPV) arising after whiplash injury and to distinguish this type of posttraumatic vertigo from other types of dizziness complained after trauma. Methods This was a retrospective study comprising patients referred to our center after whiplash injury. The patients were evaluated with neurotologic examination including bedside and instrumental tests. A Dizziness Handicap Inventory evaluating the symptoms of patients was submitted before and after treatment and was evaluated. The BPPV patients were separately evaluated from those with cervicogenic vertigo…

Comparison of repositioning maneuvers for benign paroxysmal positional vertigo of posterior semicircular canal: advantages of hybrid maneuver.

2012

Objective: The prevalence of benign paroxysmal positional vertigo (BPPV) is becoming more frequent in elderly population. The presence of comorbid factors has to be considered before assessment as well as before commencing any repositioning treatment. Our aims were evaluation of the maneuvers efficacy and evaluation of the applicability of hybrid maneuver (HM) in patients with physical limitation. Study design and setting: This is a randomized study in 2 tertiary referral centers. Intervention: This is a therapeutic intervention. Patients: All consecutive patients with diagnosis of BPPV of posterior canal matching the inclusion criteria were enrolled. Patients underwent treatment soon after…