Journal of Vestibular Research - Volume 1, issue 2

Authors: Curthoys, I.S. | Dai, M.J. | Halmagyi, G.M.

Article Type: Research Article

Abstract: One index of otolith function is the so-called oculogravic “illusion” that during centrifugal stimulation a small luminous bar, fixed with respect to the observer, appears to be roll-tilted by the same amount that the observer feels to be roll-tilted. Many patients undergoing therapeutic unilateral vestibular nerve section show the illusion symmetrically for left and right roll-tilts prior to the operation, but at testing one week after vestibular nerve section show a large asymmetry: they perceive the illusion when the resultant force is directed toward their intact ear, but they perceive a much reduced illusion when the force is directed toward …their operated ear. This roll-tilt perceptual response asymmetry appears similar to the asymmetrical horizontal semicircular canal vestibulo-ocular responses for symmetrical but opposite head accelerations that these same patients exhibit for values of head angular accelerations in the natural range (Ewald’s second law), and the present paper suggests that a version of Ewald’s second law may apply to the otolithic system: specifically, that there is a response asymmetry for linear accelerations. Anatomical and physiological evidence concerning such an otolithic asymmetry is reviewed. Show more

Keywords: otolith, torsion, oculomotor, vestibular, vestibular compensation, oculogravic illusion, ocular counterrolling, Ewald’s second law, labyrinthectomy

DOI: 10.3233/VES-1991-1211

Citation: Journal of Vestibular Research, vol. 1, no. 2, pp. 199-209, 1991

Authors: Brandt, Th. | Igarashi, M.

Article Type: Research Article

DOI: 10.3233/VES-1991-1212

Citation: Journal of Vestibular Research, vol. 1, no. 2, pp. 211-213, 1991