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The increased postural sway of patients with disorders of the vestibular system improves with vision. The suppression of pathologic nystagmus also reduces sway. Because the latter effect cannot be attributed to retinal slip as a relevant feedback for postural control, the authors investigated how eye movements rather than retinal slip affect balance. They(More)
Little is known about the vestibulo-perceptual (VP) system, particularly after a unilateral vestibular lesion. We investigated vestibulo-ocular (VO) and VP function in 25 patients with vestibular neuritis (VN) acutely (2 days after onset) and after compensation (recovery phase, 10 weeks). Since the effect of VN on reflex and perceptual function may differ(More)
We consider approximations of a smooth convex body by inscribed and circumscribed convex polytopes as the number of vertices, resp. facets tends to innnity. The measure of deviation used is the diierence of the mean width of the convex body and the approximating polytopes. The following results are obtained. (i) An asymptotic formula for best approximation.(More)
Galvanic vestibular stimulation (GVS) is reported to induce interindividually variable tonic ocular torsion (OT) and superimposed torsional nystagmus. It has been proposed that the tonic component results from the activation of otolith afferents. We tested our hypothesis that both the tonic and the phasic OT are mainly due to semicircular canal (SCC)(More)
Systematic errors in human path integration were previously associated with processing deficits in the integration of space and time. In the present work, we hypothesized that these errors are de facto the result of a system that aims to optimize its performance by incorporating knowledge about prior experience into the current estimate of displacement. We(More)
In the present study, we compared the effects of two processing modes on the updating of the location and orientation of a previously viewed object in space during a guided walk without vision. In Experiment 1, in order to measure the error for initial perception of object's orientation, 12 subjects rotated a miniature model until it matched the memorized(More)
To determine the contribution of the otoliths as well as the horizontal and vertical semicircular canals to the response of "vestibular only" neurons in the rostral fastigial nucleus of the alert monkey, we applied natural sinusoidal vestibular stimuli (0.6 Hz; +/-15 deg) around different axes. During the experiment the monkey sat erect in a primate chair(More)
BACKGROUND Downbeat nystagmus (DBN), a frequent ocular motor sign often caused by cerebellar lesions, is a fixational nystagmus with fast phases directed downward. Its precise etiology is not known. One hypothesis is that it is caused by a central imbalance of pathways of the vertical vestibulo-ocular reflex (VOR). Such an imbalance would cause not only(More)
When a subject is walking blindfolded straight ahead towards a previously seen target, the brain must update an internal representation with respect to the environment. This study examines whether the information given by the vestibular system is necessary for this simple path integration task and gives a quantitative description of locomotor behaviour(More)