Head-only rotational testing: influence of volition and vision.

Head-only rotational testing has been suggested as a method of assessing the vestibuloocular reflex in patients with reduced vestibular function as a result of ototoxicity. The purpose of this study was to investigate the influence of vision and volition on horizontal vestibuloocular reflex responses during head-only rotation in normal subjects to better define the test parameters for future clinical application. Ten asymptomatic, healthy subjects were tested using various combinations of volitional and visual conditions during head-only rotation. Results indicated that visual fixation enhanced responses slightly and that response dynamics were altered somewhat by volition. These findings provide motivation for future studies to further define head-only rotation test parameters for patients with suspected vestibular abnormalities.