BACKGROUND: Although intact vestibular function is indispensable to maintaining spatial orientation, no good screening tests of vestibular function are implemented in the aviation community. High frequency voluntary head rotation was selected as a vestibular stimulus to isolate the vestibulo-ocular reflex (VOR) from visual influence. METHOD: A dynamic visual acuity test that incorporates voluntary head rotation was evaluated as a potential vestibular function screening tool: 27 normal subjects performed voluntary sinusoidal head rotation at frequencies from 0.7-4 Hz under 3 different visual conditions: visually-enhanced VOR, normal VOR, and visually suppressed VOR. Standardized Bailey-Lovie chart letters were presented on a computer monitor in front of the subject, who then was asked to read the letters while rotating his head horizontally. The electro-oculogram and dynamic visual acuity score were recorded and analyzed. RESULTS: There was no significant difference in gain or phase shift among 3 visual conditions in the frequency range 2.8-4 Hz. The dynamic visual acuity score shifted less than 0.3 log MAR at frequencies under 2.0 Hz. CONCLUSION: The dynamic visual acuity test at frequencies around 2 Hz can be recommended for evaluating vestibular function.
BACKGROUND: Although intact vestibular function is indispensable to maintaining spatial orientation, no good screening tests of vestibular function are implemented in the aviation community. High frequency voluntary head rotation was selected as a vestibular stimulus to isolate the vestibulo-ocular reflex (VOR) from visual influence. METHOD: A dynamic visual acuity test that incorporates voluntary head rotation was evaluated as a potential vestibular function screening tool: 27 normal subjects performed voluntary sinusoidal head rotation at frequencies from 0.7-4 Hz under 3 different visual conditions: visually-enhanced VOR, normal VOR, and visually suppressed VOR. Standardized Bailey-Lovie chart letters were presented on a computer monitor in front of the subject, who then was asked to read the letters while rotating his head horizontally. The electro-oculogram and dynamic visual acuity score were recorded and analyzed. RESULTS: There was no significant difference in gain or phase shift among 3 visual conditions in the frequency range 2.8-4 Hz. The dynamic visual acuity score shifted less than 0.3 log MAR at frequencies under 2.0 Hz. CONCLUSION: The dynamic visual acuity test at frequencies around 2 Hz can be recommended for evaluating vestibular function.
Authors: Rose Marie Rine; Dale Roberts; Bree A Corbin; Roberta McKean-Cowdin; Rohit Varma; Jennifer Beaumont; Jerry Slotkin; Michael C Schubert Journal: J Rehabil Res Dev Date: 2012
Authors: Richard H Roxburgh; Renate Marquis-Nicholson; Fern Ashton; Alice M George; Rod A Lea; David Eccles; Stuart Mossman; Thomas Bird; Koen L van Gassen; Erik-Jan Kamsteeg; Donald R Love Journal: J Neurol Date: 2012-12-27 Impact factor: 4.849