Effectiveness of oculomotor function test using iPad application and its potential clinical application

Abstract

Purpose: Optokinetic nystagmus (OKN) testing is an important oculomotor function test for differentiating between central vertigo and peripheral vertigo. Bárány's hand-rolled OKN drum has been used for qualitative screening. An optokinetic stimulator that projects a visual pattern on a large screen and an installation space equivalent to it is necessary for quantitative laboratory testing. The recent advances in programming technologies have enabled the development of a mobile application (app) that allows optokinetic stimulation with controllable stimulus speed and visual pattern. We investigated the effectiveness of a locally-designed OKN app for screening oculomotor function and compared its efficacy with that of Bárány's hand-rolled OKN drum. A questionnaire survey was conducted to evaluate the test burden on the examinee. Methods: The iPad was placed in front of the subject's eyes, so that the black-and-white striped pattern of the locally-designed OKN app was at 30° with the visual angle in the horizontal direction. OKN was induced with the OKN app on the iPad or by rotating Bárány's blackand-white striped drum in either the horizontal or vertical direction. Qualitative evaluation of the ability to induce OKN was performed using ENG recordings. Results: The eye tracking of a small visual target that moved horizontally on the iPad was smooth in 11 of the 13 healthy subjects. The OKN evoked by the OKN app was sufficient for evaluation in both stimulus directions. No subject reported any autonomic symptoms such as nausea or cold sweats. Only one subject developed mild dizziness during the optokinetic stimulation. The OKN evoked by Bárány's OKN drum was also sufficient for evaluation; however, the stimulus speed was occasionally difficult to control. Conclusions: The OKN app can have a variety of uses, including in diagnosis, medical education, and vestibular rehabilitation.