Behavior of the human translational vestibulo-ocular reflex during simultaneous head translation and rotation

Issue title: The Vestibular System: A Clinical and Scientific Update in Siena. In honor of Professor Daniele Nuti, Siena, Italy, April 5–6, 2013

Guest editors: Marco Mandalàx, Stefano Ramaty and David S. Zee

Article type: Research Article

Authors: Schneider, Rosalyn^a | Liao, Ke^a | Walker, Mark F.^a | Bronstein, Adolfo^b | Leigh, R. John^{a; *}

Affiliations: [a] Department of Veterans Affairs Medical Center, Case Western Reserve University, Cleveland, OH, USA | [b] Neuro-Otology Unit, Division of Experimental Medicine, Imperial College London, Charing Cross Hospital, London, UK | [x] Otological and Skull Base Surgery Department, S.M. delle Scotte Hospital, Siena, Italy | [y] Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy

Correspondence: [*] Corresponding author: R. John Leigh, Department of Neurology, Case Medical Center, 11100 Euclid Avenue, Cleveland 44106-5040, OH, USA. Tel.: +1 216 844 3190; Fax: +1 216 231 3461; E-mail: [email protected]

Abstract: Background:During head translations, vestibular eye movements are ∼ 60% of those required to hold the line of sight on target but, during translation of the orbits due to head rotation about an eccentric axis, the eyes are held %eye on target. Objective:To resolve this paradoxical behavior of vestibulo-ocular reflexes. Methods:Subjects sat on a moving platform viewing a near target and were: (1) rotated en bloc in yaw about a vertical axis centered on the head at 1 Hz; (2) rotated with their head displaced ∼ 10 cm anterior (eccentric rotation) at 1 Hz; (3) translated along the inter-aural axis at 1.9 Hz; (4) rotated with the head centered at 1 Hz while they were translated along the inter-aural axis at 1.9 Hz. We calculated compensation ratio (CR): Eye velocity/eye velocity geometrically required to hold the eye on target. Results:During yaw, mean CR was 0.88 and during eccentric rotation CR was 0.93. During translation at 1.9 Hz, CR was 0.65. During combined rotation at 1.0 Hz and translation at 1.9 Hz, CR was 0.81 for head rotations and 0.74 for head translations. Conclusions:Translations of the orbits due to head rotation are better compensated for than translations of the orbits due to head translation. These different behaviors may be determined by context, the important difference being whether the subject is moving through the environment.

Keywords: Vestibulo-ocular reflex, head rotation, head translation, motion parallax

DOI: 10.3233/VES-140522

Journal: Journal of Vestibular Research, vol. 24, no. 5-6, pp. 329-333, 2014