ABSTRACT
The aim of this study was to establish the effect of vestibular lesion on vestibular imagery. Subjects were required to estimate verbally their passively travelled rotation angles in complete darkness, i.e., to activate vestibular imagery. During motion, the vestibulo-ocular reflex (VOR) was measured. Thus, we examined the coherence between the vestibulo-ocular reflex and self-rotation imagery, with vestibular-lesioned patients and healthy participants. Unilateral acute and chronic patients, bilateral patients, and healthy subjects were compared. The stimulus was a sequence of eight successive passive rotations, with four amplitudes (from 90° to 360°) in two directions. The VOR gain was lower in patients with unilateral lesions, for ipsilateral rotations. The healthy subjects had the highest gain and the bilateral group the lowest, on both rotation sides. Thanks to vestibular compensation after acute unilateral neuritis, the VOR gain increased in lesion side and decreased in healthy side, resulting in a similar gain in both sides. A deficit of vestibular imagery was found exclusively in patients with bilateral hyporeflexia, on both sides. The performance in vestibular imagery was good in the control group and correct in the unilateral patients. Finally, we found a significant correlation between the efficiency of the VOR and that of vestibular imagery, exclusively in the bilateral patients. The present study shows the complex relationship between vestibular imagery and the VOR. This imagery test contributes to another assessment of the spatial handicap of vestibular patients. It seems particularly interesting for patients with bilateral canal paresis and could be used to confirm this diagnosis.
Subject(s)
Imagination/physiology , Reflex, Vestibulo-Ocular/physiology , Vestibular Diseases/physiopathology , Vestibule, Labyrinth/physiopathology , Adaptation, Physiological/physiology , Adult , Aged , Analysis of Variance , Female , Functional Laterality , Humans , Male , Middle Aged , RotationABSTRACT
Twenty preterm neonates in an intensive care unit (mean gestational age, 30 weeks; mean birthweight, 1375 g) were randomly assigned to an experimental or a control group. The experimental infants were placed twice a day (for 3-h sessions) in a nonrigid reclining seat for a 6- to 7-week period. Before discharge from intensive care, the behavioral states and motor activity of the neonates were monitored during sleep-wake behavior observations (2 h). The experimental group subjects slept more, were quieter, and made fewer movements such as cloni, contraction and startles. The discussion centers on the distinct advantages of using nonrigid infant seats in a reclining position in intensive care units.
