Dynamic visual acuity testing for screening patients with vestibular impairments¹

Issue title: 8th Symposium on the Role of the Vestibular Organs in Space Exploration April 8–10, 2011, Houston, TX, USA

Guest editors: Charles M. Oman

Article type: Research Article

Authors: Peters, Brian T.^a | Mulavara, Ajitkumar P.^b | Cohen, Helen S.^{c; *} | Sangi-Haghpeykar, Haleh^c | Bloomberg, Jacob J.^d

Affiliations: [a] Wyle Integrated Science and Engineering Group, Houston, TX, USA | [b] Universities Space Research Association, Houston, TX, USA | [c] Baylor College of Medicine, Houston, TX, USA | [d] NASA/Johnson Space Center, Houston, TX, USA | Man Vehicle Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA

Correspondence: [*] Corresponding author: Helen S. Cohen, Department of Otolaryngology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA. Tel.: +1 713 798 6336; Fax: +1 713 798 8658; E-mail: hcohen@bcm.edu

Note: [1] This paper was presented at the Session: Gaze, Posture and Locomotion at the 8th Symposium on the Role of the Vestibular Organs in Space Exploration, April 8–10, 2011, Houston, TX, USA

Abstract: Dynamic visual acuity (DVA) may be a useful indicator of the function of the vestibulo-ocular reflex (VOR) but most DVA tests involve active head motion in the yaw plane. During gait the passive, vertical VOR may be more relevant and passive testing would be less likely to elicit compensatory strategies. The goal of this study was to determine if testing dynamic visual acuity during passive vertical motion of the subject would differentiate normal subjects from patients with known vestibular disorders. Subjects, normals and patients who had been diagnosed with either unilateral vestibular weaknesses or were post-acoustic neuroma resections, sat in a chair that could oscillate vertically with the head either free or constrained with a cervical orthosis. They viewed a computer screen 2 m away that showed Landholt C optotypes in one of 8 spatial configurations and which ranged in size from 0.4 to 1.0 logMAR. They were tested while the chair was stationary and while it was moving. Scores were worse for both groups during the dynamic condition compared to the static condition. In the dynamic condition patients' scores were significantly worse than normals' scores. Younger and older age groups differed slightly but significantly; the sample size was too small to examine age differences by decade. The data suggest that many well-compensated patients have dynamic visual acuity that is as good as age-matched normals. Results of ROC analyses were only moderate, indicating that the differences between patients and normals were not strong enough, under the conditions tested, for this test to be useful for screening people to determine if they have vestibular disorders. Modifications of the test paradigm may make it more useful for screening potential patients.

Keywords: Gaze stabilization, vestibulo-ocular reflex, epidemiologic screening, vestibular disorders, vestibular hypofunction

DOI: 10.3233/VES-2012-0440

Journal: Journal of Vestibular Research, vol. 22, no. 2-3, pp. 145-151, 2012